Downloaded 471 times
![What is an Array?
A variable is a storage area holding a number or text. The problem is, a variable will hold only one value.
An array is a special variable, which can store multiple values in one single variable.
If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this:
$cars1="Saab";
$cars2="Volvo";
$cars3="BMW";
However, what if you want to loop through the cars and find a specific one? And what if you had not 3 cars, but 300?
The best solution here is to use an array!
An array can hold all your variable values under a single name. And you can access the values by referring to the array name.
Each element in the array has its own index so that it can be easily accessed.
In PHP, there are three kind of arrays:
• Numeric array An array with a numeric index
• Associative array An array where each ID key is associated with a value
• Multidimensional array An array containing one or more arrays
Numeric Arrays
A numeric array stores each array element with a numeric index.
There are two methods to create a numeric array.
1. In the following example the index are automatically assigned (the index starts at 0):
$cars=array("Saab","Volvo","BMW","Toyota");
2. In the following example we assign the index manually:
$cars[0]="Saab";
$cars[1]="Volvo";
$cars[2]="BMW";
$cars[3]="Toyota";
Example
In the following example you access the variable values by referring to the array name and index:
<?php
$cars[0]="Saab";
$cars[1]="Volvo";
$cars[2]="BMW";
$cars[3]="Toyota";
echo $cars[0] . " and " . $cars[1] . " are Swedish cars.";
?>
The code above will output:
Saab and Volvo are Swedish cars.
Associative Arrays
An associative array, each ID key is associated with a value.
When storing data about specific named values, a numerical array is not always the best way to do it.
With associative arrays we can use the values as keys and assign values to them.
Example 1
In this example we use an array to assign ages to the different persons:](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-8-2048.jpg)
![$ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34);
Example 2
This example is the same as example 1, but shows a different way of creating the array:
$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";
The ID keys can be used in a script:
<?php
$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";
echo "Peter is " . $ages['Peter'] . " years old.";
?>
The code above will output:
Peter is 32 years old.
Multidimensional Arrays
In a multidimensional array, each element in the main array can also be an array. And each element in the subarray can be an array,
and so on.
Example
In this example we create a multidimensional array, with automatically assigned ID keys:
$families = array
(
"Griffin"=>array
(
"Peter",
"Lois",
"Megan"
),
"Quagmire"=>array
(
"Glenn"
),
"Brown"=>array
(
"Cleveland",
"Loretta",
"Junior"
)
);
The array above would look like this if written to the output:
Array
(
[Griffin] => Array
(
[0] => Peter
[1] => Lois
[2] => Megan
)
[Quagmire] => Array
(
[0] => Glenn
)
[Brown] => Array
(](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-9-2048.jpg)
![[0] => Cleveland
[1] => Loretta
[2] => Junior
)
)
Example 2
Lets try displaying a single value from the array above:
echo "Is " . $families['Griffin'][2] .
" a part of the Griffin family?";
The code above will output:
Is Megan a part of the Griffin family?
Complete PHP Array Reference
For a complete reference of all array functions, go to our complete PHP Array Reference.
The reference contains a brief description, and examples of use, for each function!
PHP Array Functions
PHP Array Introduction
The array functions allow you to manipulate arrays.
PHP supports both simple and multidimensional arrays. There are also specific functions for populating arrays from database
queries.
Installation
The array functions are part of the PHP core. There is no installation needed to use these functions.
PHP Array Functions
PHP: indicates the earliest version of PHP that supports the function.
Function Description PHP
array() Creates an array 3
array_change_key_case() Returns an array with all keys in lowercase or uppercase 4
array_chunk() Splits an array into chunks of arrays 4
array_combine() Creates an array by using one array for keys and another for its values 5
array_count_values() Returns an array with the number of occurrences for each value 4
array_diff() Compares array values, and returns the differences 4
array_diff_assoc() Compares array keys and values, and returns the differences 4
array_diff_key() Compares array keys, and returns the differences 5
array_diff_uassoc() Compares array keys and values, with an additional usermade function 5
check, and returns the differences
array_diff_ukey() Compares array keys, with an additional usermade function check, and 5
returns the differences
array_fill() Fills an array with values 4
array_filter() Filters elements of an array using a usermade function 4
array_flip() Exchanges all keys with their associated values in an array 4
array_intersect() Compares array values, and returns the matches 4
array_intersect_assoc() Compares array keys and values, and returns the matches 4
array_intersect_key() Compares array keys, and returns the matches 5](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-10-2048.jpg)
![Example
<html>
<body>
<?php
function add($x,$y)
{
$total=$x+$y;
return $total;
}
echo "1 + 16 = " . add(1,16);
?>
</body>
</html>
Output:
1 + 16 = 17
PHP Forms and User Input
The PHP $_GET and $_POST variables are used to retrieve information from forms, like user input.
PHP Form Handling
The most important thing to notice when dealing with HTML forms and PHP is that any form element in an HTML page will
automatically be available to your PHP scripts.
Example
The example below contains an HTML form with two input fields and a submit button:
<html>
<body>
<form action="welcome.php" method="post">
Name: <input type="text" name="fname" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
</body>
</html>
When a user fills out the form above and click on the submit button, the form data is sent to a PHP file, called "welcome.php":
"welcome.php" looks like this:
<html>
<body>
Welcome <?php echo $_POST["fname"]; ?>!<br />
You are <?php echo $_POST["age"]; ?> years old.
</body>
</html>
Output could be something like this:
Welcome John!
You are 28 years old.
The PHP $_GET and $_POST functions will be explained in the next chapters.](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-18-2048.jpg)
![Form Validation
User input should be validated on the browser whenever possible (by client scripts). Browser validation is faster and reduces the
server load.
You should consider server validation if the user input will be inserted into a database. A good way to validate a form on the server is
to post the form to itself, instead of jumping to a different page. The user will then get the error messages on the same page as the
form. This makes it easier to discover the error.
PHP $_GET Function
The builtin $_GET function is used to collect values in a form with method="get".
The $_GET Function
The builtin $_GET function is used to collect values from a form sent with method="get".
Information sent from a form with the GET method is visible to everyone (it will be displayed in the browser's address bar) and has
limits on the amount of information to send (max. 100 characters).
Example
<form action="welcome.php" method="get">
Name: <input type="text" name="fname" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
When the user clicks the "Submit" button, the URL sent to the server could look something like this:
http://www.w3schools.com/welcome.php?fname=Peter&age=37
The "welcome.php" file can now use the $_GET function to collect form data (the names of the form fields will automatically be the
keys in the $_GET array):
Welcome <?php echo $_GET["fname"]; ?>.<br />
You are <?php echo $_GET["age"]; ?> years old!
When to use method="get"?
When using method="get" in HTML forms, all variable names and values are displayed in the URL.
Note: This method should not be used when sending passwords or other sensitive information!
However, because the variables are displayed in the URL, it is possible to bookmark the page. This can be useful in some cases.
Note: The get method is not suitable for large variable values; the value cannot exceed 100 characters.
PHP $_POST Function
The builtin $_POST function is used to collect values in a form with method="post".](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-19-2048.jpg)
![The $_POST Function
The builtin $_POST function is used to collect values from a form sent with method="post".
Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send.
Note: However, there is an 8 Mb max size for the POST method, by default (can be changed by setting the post_max_size in the
php.ini file).
Example
<form action="welcome.php" method="post">
Name: <input type="text" name="fname" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
When the user clicks the "Submit" button, the URL will look like this:
http://www.w3schools.com/welcome.php
The "welcome.php" file can now use the $_POST function to collect form data (the names of the form fields will automatically be the
keys in the $_POST array):
Welcome <?php echo $_POST["fname"]; ?>!<br />
You are <?php echo $_POST["age"]; ?> years old.
When to use method="post"?
Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send.
However, because the variables are not displayed in the URL, it is not possible to bookmark the page.
The PHP $_REQUEST Function
The PHP builtin $_REQUEST function contains the contents of both $_GET, $_POST, and $_COOKIE.
The $_REQUEST function can be used to collect form data sent with both the GET and POST methods.
Example
Welcome <?php echo $_REQUEST["fname"]; ?>!<br />
You are <?php echo $_REQUEST["age"]; ?> years old.
PHP Advanced
The PHP date() function is used to format a time and/or date.
The PHP Date() Function
The PHP date() function formats a timestamp to a more readable date and time.
A timestamp is a sequence of characters, denoting the date and/or time at which a certain event occurred.
Syntax
date(format,timestamp)
Parameter Description
format Required. Specifies the format of the timestamp](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-20-2048.jpg)
![</body>
</html>
Error message:
Warning: include(wrongFile.php) [function.include]:
failed to open stream:
No such file or directory in C:homewebsitetest.php on line 5
Warning: include() [function.include]:
Failed opening 'wrongFile.php' for inclusion
(include_path='.;C:php5pear')
in C:homewebsitetest.php on line 5
Hello World!
Notice that the echo statement is executed! This is because a Warning does not stop the script execution.
Error Example require() Function
Now, let's run the same example with the require() function.
<html>
<body>
<?php
require("wrongFile.php");
echo "Hello World!";
?>
</body>
</html>
Error message:
Warning: require(wrongFile.php) [function.require]:
failed to open stream:
No such file or directory in C:homewebsitetest.php on line 5
Fatal error: require() [function.require]:
Failed opening required 'wrongFile.php'
(include_path='.;C:php5pear')
in C:homewebsitetest.php on line 5
The echo statement is not executed, because the script execution stopped after the fatal error.
It is recommended to use the require() function instead of include(), because scripts should not continue after an error.
PHP File Handling
The fopen() function is used to open files in PHP.
Opening a File
The fopen() function is used to open files in PHP.
The first parameter of this function contains the name of the file to be opened and the second parameter specifies in which mode the
file should be opened:
<html>
<body>
<?php
$file=fopen("welcome.txt","r");
?>](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-25-2048.jpg)
![<?php
if ($_FILES["file"]["error"] > 0)
{
echo "Error: " . $_FILES["file"]["error"] . "<br />";
}
else
{
echo "Upload: " . $_FILES["file"]["name"] . "<br />";
echo "Type: " . $_FILES["file"]["type"] . "<br />";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
echo "Stored in: " . $_FILES["file"]["tmp_name"];
}
?>
By using the global PHP $_FILES array you can upload files from a client computer to the remote server.
The first parameter is the form's input name and the second index can be either "name", "type", "size", "tmp_name" or "error". Like
this:
• $_FILES["file"]["name"] the name of the uploaded file
• $_FILES["file"]["type"] the type of the uploaded file
• $_FILES["file"]["size"] the size in bytes of the uploaded file
• $_FILES["file"]["tmp_name"] the name of the temporary copy of the file stored on the server
• $_FILES["file"]["error"] the error code resulting from the file upload
This is a very simple way of uploading files. For security reasons, you should add restrictions on what the user is allowed to upload.
Restrictions on Upload
In this script we add some restrictions to the file upload. The user may only upload .gif or .jpeg files and the file size must be under
20 kb:
<?php
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/pjpeg"))
&& ($_FILES["file"]["size"] < 20000))
{
if ($_FILES["file"]["error"] > 0)
{
echo "Error: " . $_FILES["file"]["error"] . "<br />";
}
else
{
echo "Upload: " . $_FILES["file"]["name"] . "<br />";
echo "Type: " . $_FILES["file"]["type"] . "<br />";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
echo "Stored in: " . $_FILES["file"]["tmp_name"];
}
}
else
{
echo "Invalid file";
}
?>
Note: For IE to recognize jpg files the type must be pjpeg, for FireFox it must be jpeg.
Saving the Uploaded File
The examples above create a temporary copy of the uploaded files in the PHP temp folder on the server.
The temporary copied files disappears when the script ends. To store the uploaded file we need to copy it to a different location:](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-31-2048.jpg)
![<?php
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/pjpeg"))
&& ($_FILES["file"]["size"] < 20000))
{
if ($_FILES["file"]["error"] > 0)
{
echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
}
else
{
echo "Upload: " . $_FILES["file"]["name"] . "<br />";
echo "Type: " . $_FILES["file"]["type"] . "<br />";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";
if (file_exists("upload/" . $_FILES["file"]["name"]))
{
echo $_FILES["file"]["name"] . " already exists. ";
}
else
{
move_uploaded_file($_FILES["file"]["tmp_name"],
"upload/" . $_FILES["file"]["name"]);
echo "Stored in: " . "upload/" . $_FILES["file"]["name"];
}
}
}
else
{
echo "Invalid file";
}
?>
The script above checks if the file already exists, if it does not, it copies the file to the specified folder.
Note: This example saves the file to a new folder called "upload"
PHP Cookies
A cookie is often used to identify a user.
What is a Cookie?
A cookie is often used to identify a user. A cookie is a small file that the server embeds on the user's computer. Each time the same
computer requests a page with a browser, it will send the cookie too. With PHP, you can both create and retrieve cookie values.
How to Create a Cookie?
The setcookie() function is used to set a cookie.
Note: The setcookie() function must appear BEFORE the <html> tag.
Syntax
setcookie(name, value, expire, path, domain);](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-32-2048.jpg)
![Example 1
In the example below, we will create a cookie named "user" and assign the value "Alex Porter" to it. We also specify that the cookie
should expire after one hour:
<?php
setcookie("user", "Alex Porter", time()+3600);
?>
<html>
.....
Note: The value of the cookie is automatically URLencoded when sending the cookie, and automatically decoded when received (to
prevent URLencoding, use setrawcookie() instead).
Example 2
You can also set the expiration time of the cookie in another way. It may be easier than using seconds.
<?php
$expire=time()+60*60*24*30;
setcookie("user", "Alex Porter", $expire);
?>
<html>
.....
In the example above the expiration time is set to a month (60 sec * 60 min * 24 hours * 30 days).
How to Retrieve a Cookie Value?
The PHP $_COOKIE variable is used to retrieve a cookie value.
In the example below, we retrieve the value of the cookie named "user" and display it on a page:
<?php
// Print a cookie
echo $_COOKIE["user"];
// A way to view all cookies
print_r($_COOKIE);
?>
In the following example we use the isset() function to find out if a cookie has been set:
<html>
<body>
<?php
if (isset($_COOKIE["user"]))
echo "Welcome " . $_COOKIE["user"] . "!<br />";
else
echo "Welcome guest!<br />";
?>
</body>
</html>
How to Delete a Cookie?
When deleting a cookie you should assure that the expiration date is in the past.
Delete example:
<?php
// set the expiration date to one hour ago](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-33-2048.jpg)
![setcookie("user", "", time()3600);
?>
What if a Browser Does NOT Support Cookies?
If your application deals with browsers that do not support cookies, you will have to use other methods to pass information from one
page to another in your application. One method is to pass the data through forms (forms and user input are described earlier in this
tutorial).
The form below passes the user input to "welcome.php" when the user clicks on the "Submit" button:
<html>
<body>
<form action="welcome.php" method="post">
Name: <input type="text" name="name" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
</body>
</html>
Retrieve the values in the "welcome.php" file like this:
<html>
<body>
Welcome <?php echo $_POST["name"]; ?>.<br />
You are <?php echo $_POST["age"]; ?> years old.
</body>
</html>
PHP Sessions
A PHP session variable is used to store information about, or change settings for a user session. Session variables hold information
about one single user, and are available to all pages in one application.
PHP Session Variables
When you are working with an application, you open it, do some changes and then you close it. This is much like a Session. The
computer knows who you are. It knows when you start the application and when you end. But on the internet there is one problem:
the web server does not know who you are and what you do because the HTTP address doesn't maintain state.
A PHP session solves this problem by allowing you to store user information on the server for later use (i.e. username, shopping
items, etc). However, session information is temporary and will be deleted after the user has left the website. If you need a permanent
storage you may want to store the data in a database.
Sessions work by creating a unique id (UID) for each visitor and store variables based on this UID. The UID is either stored in a
cookie or is propagated in the URL.
Starting a PHP Session
Before you can store user information in your PHP session, you must first start up the session.
Note: The session_start() function must appear BEFORE the <html> tag:](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-34-2048.jpg)
![<?php session_start(); ?>
<html>
<body>
</body>
</html>
The code above will register the user's session with the server, allow you to start saving user information, and assign a UID for that
user's session.
Storing a Session Variable
The correct way to store and retrieve session variables is to use the PHP $_SESSION variable:
<?php
session_start();
// store session data
$_SESSION['views']=1;
?>
<html>
<body>
<?php
//retrieve session data
echo "Pageviews=". $_SESSION['views'];
?>
</body>
</html>
Output:
Pageviews=1
In the example below, we create a simple pageviews counter. The isset() function checks if the "views" variable has already been set.
If "views" has been set, we can increment our counter. If "views" doesn't exist, we create a "views" variable, and set it to 1:
<?php
session_start();
if(isset($_SESSION['views']))
$_SESSION['views']=$_SESSION['views']+1;
else
$_SESSION['views']=1;
echo "Views=". $_SESSION['views'];
?>
Destroying a Session
If you wish to delete some session data, you can use the unset() or the session_destroy() function.
The unset() function is used to free the specified session variable:
<?php
unset($_SESSION['views']);
?>
You can also completely destroy the session by calling the session_destroy() function:
<?php
session_destroy();
?>
Note: session_destroy() will reset your session and you will lose all your stored session data.](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-35-2048.jpg)
![PHP Sending Emails
PHP allows you to send emails directly from a script.
The PHP mail() Function
The PHP mail() function is used to send emails from inside a script.
Syntax
mail(to,subject,message,headers,parameters)
Parameter Description
to Required. Specifies the receiver / receivers of the email
subject Required. Specifies the subject of the email. Note: This parameter cannot contain any newline
characters
message Required. Defines the message to be sent. Each line should be separated with a LF (n). Lines
should not exceed 70 characters
headers Optional. Specifies additional headers, like From, Cc, and Bcc. The additional headers should
be separated with a CRLF (rn)
parameters Optional. Specifies an additional parameter to the sendmail program
Note: For the mail functions to be available, PHP requires an installed and working email system. The program to be
used is defined by the configuration settings in the php.ini file. Read more in our PHP Mail reference.
PHP Simple EMail
The simplest way to send an email with PHP is to send a text email.
In the example below we first declare the variables ($to, $subject, $message, $from, $headers), then we use the
variables in the mail() function to send an email:
<?php
$to = "someone@example.com";
$subject = "Test mail";
$message = "Hello! This is a simple email message.";
$from = "someonelse@example.com";
$headers = "From: $from";
mail($to,$subject,$message,$headers);
echo "Mail Sent.";
?>
PHP Mail Form
With PHP, you can create a feedbackform on your website. The example below sends a text message to a specified e
mail address:
<html>
<body>
<?php
if (isset($_REQUEST['email']))
//if "email" is filled out, send email
{
//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-36-2048.jpg)
![$message = $_REQUEST['message'] ;
mail( "someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
else
//if "email" is not filled out, display the form
{
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text' /><br />
Subject: <input name='subject' type='text' /><br />
Message:<br />
<textarea name='message' rows='15' cols='40'>
</textarea><br />
<input type='submit' />
</form>";
}
?>
</body>
</html>
This is how the example above works:
• First, check if the email input field is filled out
• If it is not set (like when the page is first visited); output the HTML form
• If it is set (after the form is filled out); send the email from the form
• When submit is pressed after the form is filled out, the page reloads, sees that the email input is set, and
sends the email
Note: This is the simplest way to send email, but it is not secure. In the next chapter of this tutorial you can read more
about vulnerabilities in email scripts, and how to validate user input to make it more secure.
PHP Mail Reference
For more information about the PHP mail() function, visit our PHP Mail Reference.
PHP Mail Functions
PHP Mail Introduction
The mail() function allows you to send emails directly from a script.
Requirements
For the mail functions to be available, PHP requires an installed and working email system. The program to be used is defined by the
configuration settings in the php.ini file.
Installation
The mail functions are part of the PHP core. There is no installation needed to use these functions.](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-37-2048.jpg)
![Runtime Configuration
The behavior of the mail functions is affected by settings in the php.ini file.
Mail configuration options:
Name Default Description Changeable
SMTP "localhost" Windows only: The DNS name or IP address of the PHP_INI_ALL
SMTP server
smtp_port "25" Windows only: The SMTP port number. Available PHP_INI_ALL
since PHP 4.3
sendmail_from NULL Windows only: Specifies the "from" address to be used PHP_INI_ALL
in email sent from PHP
sendmail_path NULL Unix systems only: Specifies where the sendmail PHP_INI_SYSTEM
program can be found (usually /usr/sbin/sendmail or
/usr/lib/sendmail)
PHP Mail Functions
PHP: indicates the earliest version of PHP that supports the function.
Function Description PHP
ezmlm_hash() Calculates the hash value needed by the EZMLM mailing list system 3
mail() Allows you to send emails directly from a script 3
PHP Mail Constants
none
PHP Secure Emails
« Previous Next Chapter »
There is a weakness in the PHP email script in the previous chapter.
PHP Email Injections
First, look at the PHP code from the previous chapter:
<html>
<body>
<?php
if (isset($_REQUEST['email']))
//if "email" is filled out, send email
{
//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-38-2048.jpg)
![echo "Thank you for using our mail form";
}
else
//if "email" is not filled out, display the form
{
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text' /><br />
Subject: <input name='subject' type='text' /><br />
Message:<br />
<textarea name='message' rows='15' cols='40'>
</textarea><br />
<input type='submit' />
</form>";
}
?>
</body>
</html>
The problem with the code above is that unauthorized users can insert data into the mail headers via the input form.
What happens if the user adds the following text to the email input field in the form?
someone@example.com%0ACc:person2@example.com
%0ABcc:person3@example.com,person3@example.com,
anotherperson4@example.com,person5@example.com
%0ABTo:person6@example.com
The mail() function puts the text above into the mail headers as usual, and now the header has an extra Cc:, Bcc:, and
To: field. When the user clicks the submit button, the email will be sent to all of the addresses above!
PHP Stopping Email Injections
The best way to stop email injections is to validate the input.
The code below is the same as in the previous chapter, but now we have added an input validator that checks the email
field in the form:
<html>
<body>
<?php
function spamcheck($field)
{
//filter_var() sanitizes the email
//address using FILTER_SANITIZE_EMAIL
$field=filter_var($field, FILTER_SANITIZE_EMAIL);
//filter_var() validates the email
//address using FILTER_VALIDATE_EMAIL
if(filter_var($field, FILTER_VALIDATE_EMAIL))
{
return TRUE;
}
else
{
return FALSE;
}
}
if (isset($_REQUEST['email']))
{//if "email" is filled out, proceed
//check if the email address is invalid
$mailcheck = spamcheck($_REQUEST['email']);](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-39-2048.jpg)
![if ($mailcheck==FALSE)
{
echo "Invalid input";
}
else
{//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
}
else
{//if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text' /><br />
Subject: <input name='subject' type='text' /><br />
Message:<br />
<textarea name='message' rows='15' cols='40'>
</textarea><br />
<input type='submit' />
</form>";
}
?>
</body>
</html>
In the code above we use PHP filters to validate input:
• The FILTER_SANITIZE_EMAIL filter removes all illegal email characters from a string
• The FILTER_VALIDATE_EMAIL filter validates value as an email address
You can read more about filters in our PHP Filter chapter.
PHP Error Handling
The default error handling in PHP is very simple. An error message with filename, line number and a message describing the error is
sent to the browser.
PHP Error Handling
When creating scripts and web applications, error handling is an important part. If your code lacks error checking code, your program
may look very unprofessional and you may be open to security risks.
This tutorial contains some of the most common error checking methods in PHP.
We will show different error handling methods:
• Simple "die()" statements
• Custom errors and error triggers
• Error reporting](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-40-2048.jpg)
![Basic Error Handling: Using the die() function
The first example shows a simple script that opens a text file:
<?php
$file=fopen("welcome.txt","r");
?>
If the file does not exist you might get an error like this:
Warning: fopen(welcome.txt) [function.fopen]: failed to open stream:
No such file or directory in C:webfoldertest.php on line 2
To avoid that the user gets an error message like the one above, we test if the file exist before we try to access it:
<?php
if(!file_exists("welcome.txt"))
{
die("File not found");
}
else
{
$file=fopen("welcome.txt","r");
}
?>
Now if the file does not exist you get an error like this:
File not found
The code above is more efficient than the earlier code, because it uses a simple error handling mechanism to stop the script after the
error.
However, simply stopping the script is not always the right way to go. Let's take a look at alternative PHP functions for handling
errors.
Creating a Custom Error Handler
Creating a custom error handler is quite simple. We simply create a special function that can be called when an error occurs in PHP.
This function must be able to handle a minimum of two parameters (error level and error message) but can accept up to five
parameters (optionally: file, linenumber, and the error context):
Syntax
error_function(error_level,error_message,
error_file,error_line,error_context)
Parameter Description
error_level Required. Specifies the error report level for the userdefined error. Must be a value number. See table
below for possible error report levels
error_message Required. Specifies the error message for the userdefined error
error_file Optional. Specifies the filename in which the error occurred
error_line Optional. Specifies the line number in which the error occurred
error_context Optional. Specifies an array containing every variable, and their values, in use when the error occurred
Error Report levels
These error report levels are the different types of error the userdefined error handler can be used for:
Value Constant Description
2 E_WARNING Nonfatal runtime errors. Execution of the script is not halted
8 E_NOTICE Runtime notices. The script found something that might be an error, but could
also happen when running a script normally
256 E_USER_ERROR Fatal usergenerated error. This is like an E_ERROR set by the programmer
using the PHP function trigger_error()
512 E_USER_WARNING Nonfatal usergenerated warning. This is like an E_WARNING set by the](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-41-2048.jpg)
![programmer using the PHP function trigger_error()
1024 E_USER_NOTICE Usergenerated notice. This is like an E_NOTICE set by the programmer using
the PHP function trigger_error()
4096 E_RECOVERABLE_ERROR Catchable fatal error. This is like an E_ERROR but can be caught by a user
defined handle (see also set_error_handler())
8191 E_ALL All errors and warnings, except level E_STRICT (E_STRICT will be part of
E_ALL as of PHP 6.0)
Now lets create a function to handle errors:
function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr<br />";
echo "Ending Script";
die();
}
The code above is a simple error handling function. When it is triggered, it gets the error level and an error message. It then outputs
the error level and message and terminates the script.
Now that we have created an error handling function we need to decide when it should be triggered.
Set Error Handler
The default error handler for PHP is the built in error handler. We are going to make the function above the default error handler for
the duration of the script.
It is possible to change the error handler to apply for only some errors, that way the script can handle different errors in different
ways. However, in this example we are going to use our custom error handler for all errors:
set_error_handler("customError");
Since we want our custom function to handle all errors, the set_error_handler() only needed one parameter, a second parameter could
be added to specify an error level.
Example
Testing the error handler by trying to output variable that does not exist:
<?php
//error handler function
function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr";
}
//set error handler
set_error_handler("customError");
//trigger error
echo($test);
?>
The output of the code above should be something like this:
Error: [8] Undefined variable: test
Trigger an Error
In a script where users can input data it is useful to trigger errors when an illegal input occurs. In PHP, this is done by the
trigger_error() function.
Example
In this example an error occurs if the "test" variable is bigger than "1":](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-42-2048.jpg)
![<?php
$test=2;
if ($test>1)
{
trigger_error("Value must be 1 or below");
}
?>
The output of the code above should be something like this:
Notice: Value must be 1 or below
in C:webfoldertest.php on line 6
An error can be triggered anywhere you wish in a script, and by adding a second parameter, you can specify what error level is
triggered.
Possible error types:
• E_USER_ERROR Fatal usergenerated runtime error. Errors that can not be recovered from. Execution of the script is
halted
• E_USER_WARNING Nonfatal usergenerated runtime warning. Execution of the script is not halted
• E_USER_NOTICE Default. Usergenerated runtime notice. The script found something that might be an error, but could
also happen when running a script normally
Example
In this example an E_USER_WARNING occurs if the "test" variable is bigger than "1". If an E_USER_WARNING occurs we will
use our custom error handler and end the script:
<?php
//error handler function
function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr<br />";
echo "Ending Script";
die();
}
//set error handler
set_error_handler("customError",E_USER_WARNING);
//trigger error
$test=2;
if ($test>1)
{
trigger_error("Value must be 1 or below",E_USER_WARNING);
}
?>
The output of the code above should be something like this:
Error: [512] Value must be 1 or below
Ending Script
Now that we have learned to create our own errors and how to trigger them, lets take a look at error logging.
Error Logging
By default, PHP sends an error log to the servers logging system or a file, depending on how the error_log configuration is set in the
php.ini file. By using the error_log() function you can send error logs to a specified file or a remote destination.
Sending errors messages to yourself by email can be a good way of getting notified of specific errors.
Send an Error Message by EMail
In the example below we will send an email with an error message and end the script, if a specific error occurs:
<?php
//error handler function](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-43-2048.jpg)
![function customError($errno, $errstr)
{
echo "<b>Error:</b> [$errno] $errstr<br />";
echo "Webmaster has been notified";
error_log("Error: [$errno] $errstr",1,
"someone@example.com","From: webmaster@example.com");
}
//set error handler
set_error_handler("customError",E_USER_WARNING);
//trigger error
$test=2;
if ($test>1)
{
trigger_error("Value must be 1 or below",E_USER_WARNING);
}
?>
The output of the code above should be something like this:
Error: [512] Value must be 1 or below
Webmaster has been notified
And the mail received from the code above looks like this:
Error: [512] Value must be 1 or below
This should not be used with all errors. Regular errors should be logged on the server using the default PHP logging system.
PHP Exception Handling
Exceptions are used to change the normal flow of a script if a specified error occurs
What is an Exception
With PHP 5 came a new object oriented way of dealing with errors.
Exception handling is used to change the normal flow of the code execution if a specified error (exceptional) condition occurs. This
condition is called an exception.
This is what normally happens when an exception is triggered:
• The current code state is saved
• The code execution will switch to a predefined (custom) exception handler function
• Depending on the situation, the handler may then resume the execution from the saved code state, terminate the script
execution or continue the script from a different location in the code
We will show different error handling methods:
• Basic use of Exceptions
• Creating a custom exception handler
• Multiple exceptions
• Rethrowing an exception
• Setting a top level exception handler
Note: Exceptions should only be used with error conditions, and should not be used to jump to another place in the code at a
specified point.](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-44-2048.jpg)
![if(!filter_has_var(INPUT_POST, "url"))
{
echo("Input type does not exist");
}
else
{
$url = filter_input(INPUT_POST,
"url", FILTER_SANITIZE_URL);
}
?>
Example Explained
The example above has an input (url) sent to it using the "POST" method:
1. Check if the "url" input of the "POST" type exists
2. If the input variable exists, sanitize (take away invalid characters) and store it in the $url variable
If the input variable is a string like this "http://www.W3ååSchøøools.com/", the $url variable after the sanitizing will look like this:
http://www.W3Schools.com/
Filter Multiple Inputs
A form almost always consist of more than one input field. To avoid calling the filter_var or filter_input functions over and over, we
can use the filter_var_array or the filter_input_array functions.
In this example we use the filter_input_array() function to filter three GET variables. The received GET variables is a name, an age
and an email address:
<?php
$filters = array
(
"name" => array
(
"filter"=>FILTER_SANITIZE_STRING
),
"age" => array
(
"filter"=>FILTER_VALIDATE_INT,
"options"=>array
(
"min_range"=>1,
"max_range"=>120
)
),
"email"=> FILTER_VALIDATE_EMAIL,
);
$result = filter_input_array(INPUT_GET, $filters);
if (!$result["age"])
{
echo("Age must be a number between 1 and 120.<br />");
}
elseif(!$result["email"])
{
echo("EMail is not valid.<br />");
}
else
{
echo("User input is valid");
}
?>](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-52-2048.jpg)
![$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
$sql="INSERT INTO Persons (FirstName, LastName, Age)
VALUES
('$_POST[firstname]','$_POST[lastname]','$_POST[age]')";
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
echo "1 record added";
mysql_close($con)
?>
PHP MySQL Select
The SELECT statement is used to select data from a database.
Select Data From a Database Table
The SELECT statement is used to select data from a database.
Syntax
SELECT column_name(s)
FROM table_name
To learn more about SQL, please visit our SQL tutorial.
To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or
command to a MySQL connection.
Example
The following example selects all the data stored in the "Persons" table (The * character selects all the data in the table):
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
$result = mysql_query("SELECT * FROM Persons");
while($row = mysql_fetch_array($result))
{
echo $row['FirstName'] . " " . $row['LastName'];
echo "<br />";
}
mysql_close($con);
?>](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-59-2048.jpg)
![The example above stores the data returned by the mysql_query() function in the $result variable.
Next, we use the mysql_fetch_array() function to return the first row from the recordset as an array. Each call to mysql_fetch_array()
returns the next row in the recordset. The while loop loops through all the records in the recordset. To print the value of each row, we
use the PHP $row variable ($row['FirstName'] and $row['LastName']).
The output of the code above will be:
Peter Griffin
Glenn Quagmire
Display the Result in an HTML Table
The following example selects the same data as the example above, but will display the data in an HTML table:
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
$result = mysql_query("SELECT * FROM Persons");
echo "<table border='1'>
<tr>
<th>Firstname</th>
<th>Lastname</th>
</tr>";
while($row = mysql_fetch_array($result))
{
echo "<tr>";
echo "<td>" . $row['FirstName'] . "</td>";
echo "<td>" . $row['LastName'] . "</td>";
echo "</tr>";
}
echo "</table>";
mysql_close($con);
?>
The output of the code above will be:
Firstname Lastname
Glenn Quagmire
Peter Griffin
PHP MySQL The Where Clause
The WHERE clause is used to filter records.
The WHERE clause
The WHERE clause is used to extract only those records that fulfill a specified criterion.](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-60-2048.jpg)
![Syntax
SELECT column_name(s)
FROM table_name
WHERE column_name operator value
To learn more about SQL, please visit our SQL tutorial.
To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or
command to a MySQL connection.
Example
The following example selects all rows from the "Persons" table where "FirstName='Peter':
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
$result = mysql_query("SELECT * FROM Persons
WHERE FirstName='Peter'");
while($row = mysql_fetch_array($result))
{
echo $row['FirstName'] . " " . $row['LastName'];
echo "<br />";
}
?>
The output of the code above will be:
Peter Griffin
PHP MySQL Order By Keyword
The ORDER BY keyword is used to sort the data in a recordset.
The ORDER BY Keyword
The ORDER BY keyword is used to sort the data in a recordset.
The ORDER BY keyword sort the records in ascending order by default.
If you want to sort the records in a descending order, you can use the DESC keyword.
Syntax
SELECT column_name(s)
FROM table_name
ORDER BY column_name(s) ASC|DESC
To learn more about SQL, please visit our SQL tutorial.
Example
The following example selects all the data stored in the "Persons" table, and sorts the result by the "Age" column:
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-61-2048.jpg)
![{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
$result = mysql_query("SELECT * FROM Persons ORDER BY age");
while($row = mysql_fetch_array($result))
{
echo $row['FirstName'];
echo " " . $row['LastName'];
echo " " . $row['Age'];
echo "<br />";
}
mysql_close($con);
?>
The output of the code above will be:
Glenn Quagmire 33
Peter Griffin 35
Order by Two Columns
It is also possible to order by more than one column. When ordering by more than one column, the second column is only used if the
values in the first column are equal:
SELECT column_name(s)
FROM table_name
ORDER BY column1, column2
PHP MySQL Update
The UPDATE statement is used to modify data in a table.
Update Data In a Database
The UPDATE statement is used to update existing records in a table.
Syntax
UPDATE table_name
SET column1=value, column2=value2,...
WHERE some_column=some_value
Note: Notice the WHERE clause in the UPDATE syntax. The WHERE clause specifies which record or records that should be
updated. If you omit the WHERE clause, all records will be updated!
To learn more about SQL, please visit our SQL tutorial.
To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or
command to a MySQL connection.
Example
Earlier in the tutorial we created a table named "Persons". Here is how it looks:](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-62-2048.jpg)
![</body>
</html>
Source code explanation:
If the input field is empty (str.length==0), the function clears the content of the txtHint placeholder and exits the function.
If the input field is not empty, the showHint() function executes the following:
• Define the filename (to request from the server) in a variable called url
• Add a parameter (q) to the url variable, with the content of the input field
• Add a random number to the url variable, to avoid getting a cached file
• Create an XMLHttpRequest object
• Create the function to be executed when the server response is ready
• Send the request off to the server
The PHP File
The page on the server called by the JavaScript above is a PHP file called "gethint.php".
The source code in "gethint.php" checks an array of names, and returns the corresponding name(s) to the browser:
<?php
// Fill up array with names
$a[]="Anna";
$a[]="Brittany";
$a[]="Cinderella";
$a[]="Diana";
$a[]="Eva";
$a[]="Fiona";
$a[]="Gunda";
$a[]="Hege";
$a[]="Inga";
$a[]="Johanna";
$a[]="Kitty";
$a[]="Linda";
$a[]="Nina";
$a[]="Ophelia";
$a[]="Petunia";
$a[]="Amanda";
$a[]="Raquel";
$a[]="Cindy";
$a[]="Doris";
$a[]="Eve";
$a[]="Evita";
$a[]="Sunniva";
$a[]="Tove";
$a[]="Unni";
$a[]="Violet";
$a[]="Liza";
$a[]="Elizabeth";
$a[]="Ellen";
$a[]="Wenche";
$a[]="Vicky";
//get the q parameter from URL
$q=$_GET["q"];
//lookup all hints from array if length of q>0
if (strlen($q) > 0)
{
$hint="";](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-75-2048.jpg)
![for($i=0; $i<count($a); $i++)
{
if (strtolower($q)==strtolower(substr($a[$i],0,strlen($q))))
{
if ($hint=="")
{
$hint=$a[$i];
}
else
{
$hint=$hint." , ".$a[$i];
}
}
}
}
// Set output to "no suggestion" if no hint were found
// or to the correct values
if ($hint == "")
{
$response="no suggestion";
}
else
{
$response=$hint;
}
//output the response
echo $response;
?>
Explanation: If there is any text sent from the JavaScript (strlen($q) > 0), the following happens:
1. Find a name matching the characters sent from the JavaScript
2. If no match were found, set the response string to "no suggestion"
3. If one or more matching names were found, set the response string to all these names
4. The response is sent to the "txtHint" placeholder
PHP AJAX and MySQL
AJAX is used for interactive communication with a database.
AJAX Database Example
The following example will demonstrate how a web page can fetch information from a database with AJAX:
Example
þÿPeter Griffin
Select a person:
Person info will be listed here...](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-76-2048.jpg)
![• Add a parameter (q) to the url variable, with the content of the dropdown list
• Add a random number to the url variable, to avoid getting a cached file
• Create an XMLHttpRequest object
• Create the function to be executed when the server response is ready
• Send the request off to the server
The PHP File
The page on the server called by the JavaScript above is a PHP file called "getuser.php".
The source code in "getuser.php" runs a query against a MySQL database, and returns the result in an HTML table:
<?php
$q=$_GET["q"];
$con = mysql_connect('localhost', 'peter', 'abc123');
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("ajax_demo", $con);
$sql="SELECT * FROM user WHERE id = '".$q."'";
$result = mysql_query($sql);
echo "<table border='1'>
<tr>
<th>Firstname</th>
<th>Lastname</th>
<th>Age</th>
<th>Hometown</th>
<th>Job</th>
</tr>";
while($row = mysql_fetch_array($result))
{
echo "<tr>";
echo "<td>" . $row['FirstName'] . "</td>";
echo "<td>" . $row['LastName'] . "</td>";
echo "<td>" . $row['Age'] . "</td>";
echo "<td>" . $row['Hometown'] . "</td>";
echo "<td>" . $row['Job'] . "</td>";
echo "</tr>";
}
echo "</table>";
mysql_close($con);
?>
Explanation: When the query is sent from the JavaScript to the PHP file, the following happens:
1. PHP opens a connection to a MySQL server
2. The correct person is found
3. An HTML table is created, filled with data, and sent back to the "txtHint" placeholder
PHP Example AJAX and XML
AJAX can be used for interactive communication with an XML file.](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-78-2048.jpg)
![</html>
The showCD() function does the following:
• Define the filename (to request from the server) in a variable called url
• Add a parameter (q) to the url variable, with the content of the dropdown list
• Add a random number to the url variable, to avoid getting a cached file
• Create an XMLHttpRequest object
• Create the function to be executed when the server response is ready
• Send the request off to the server
The PHP File
The page on the server called by the JavaScript above is a PHP file called "getcd.php".
The PHP script loads an XML document, "cd_catalog.xml", runs a query against the XML file, and returns the result as HTML:
<?php
$q=$_GET["q"];
$xmlDoc = new DOMDocument();
$xmlDoc>load("cd_catalog.xml");
$x=$xmlDoc>getElementsByTagName('ARTIST');
for ($i=0; $i<=$x>length1; $i++)
{
//Process only element nodes
if ($x>item($i)>nodeType==1)
{
if ($x>item($i)>childNodes>item(0)>nodeValue == $q)
{
$y=($x>item($i)>parentNode);
}
}
}
$cd=($y>childNodes);
for ($i=0;$i<$cd>length;$i++)
{
//Process only element nodes
if ($cd>item($i)>nodeType==1)
{
echo("<b>" . $cd>item($i)>nodeName . ":</b> ");
echo($cd>item($i)>childNodes>item(0)>nodeValue);
echo("<br />");
}
}
?>
When the CD query is sent from the JavaScript to the PHP page, the following happens:
1. PHP creates an XML DOM object
2. Find all <artist> elements that matches the name sent from the JavaScript
3. Output the album information (send to the "txtHint" placeholder)
PHP Example AJAX Live Search
AJAX can be used for a more userfriendly and interactive search.](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-80-2048.jpg)
![The code searches an XML file for titles matching the search string and returns the result as HTML:
<?php
$xmlDoc = new DOMDocument();
$xmlDoc>load("links.xml");
$x=$xmlDoc>getElementsByTagName('link');
//get the q parameter from URL
$q=$_GET["q"];
//lookup all links from the xml file if length of q>0
if (strlen($q) > 0)
{
$hint="";
for($i=0; $i<($x>length); $i++)
{
$y=$x>item($i)>getElementsByTagName('title');
$z=$x>item($i)>getElementsByTagName('url');
if ($y>item(0)>nodeType==1)
{
//find a link matching the search text
if (stristr($y>item(0)>childNodes>item(0)>nodeValue,$q))
{
if ($hint=="")
{
$hint="<a href='" .
$z>item(0)>childNodes>item(0)>nodeValue .
"' target='_blank'>" .
$y>item(0)>childNodes>item(0)>nodeValue . "</a>";
}
else
{
$hint=$hint . "<br /><a href='" .
$z>item(0)>childNodes>item(0)>nodeValue .
"' target='_blank'>" .
$y>item(0)>childNodes>item(0)>nodeValue . "</a>";
}
}
}
}
}
// Set output to "no suggestion" if no hint were found
// or to the correct values
if ($hint == "")
{
$response="no suggestion";
}
else
{
$response=$hint;
}
//output the response
echo $response;
?>
If there is any text sent from the JavaScript (strlen($q) > 0), the following happens:
1. PHP creates an XML DOM object of the "links.xml" file
2. Loops through all <title> elements to find titles that match the text sent from the JavaScript
3. Sets the correct link and title in the "$response" variable. If more than one match is found, all matches are added to the
variable
4. If no matches are found, the $response variable is set to "no suggestion"
5. Output the $respone variable to the "livesearch" placeholder](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-83-2048.jpg)
![xmlhttp.send(null);
}
function stateChanged()
{
if (xmlhttp.readyState==4)
{
document.getElementById("rssOutput").innerHTML=xmlhttp.responseText;
}
}
function GetXmlHttpObject()
{
if (window.XMLHttpRequest)
{
// code for IE7+, Firefox, Chrome, Opera, Safari
return new XMLHttpRequest();
}
if (window.ActiveXObject)
{
// code for IE6, IE5
return new ActiveXObject("Microsoft.XMLHTTP");
}
return null;
}
The stateChanged() and GetXmlHttpObject functions are the same as in the PHP AJAX Suggest chapter.
The showRSS() Function
Every time an option is selected in the input field, this function executes the following:
1. Calls the GetXmlHttpObject() function to create an XMLHTTP object
2. Defines the URL (filename) to send to the server
3. Adds a parameter (q) to the URL with the selected option from the dropdown list
4. Adds a random number to prevent the server from using a cached file
5. Each time the readyState property changes, the stateChanged() function will be executed
6. Opens the XMLHTTP object with the given URL
7. Sends an HTTP request to the server
Example Explained The PHP page
The PHP page called by the JavaScript code is called "getrss.php":
<?php
//get the q parameter from URL
$q=$_GET["q"];
//find out which feed was selected
if($q=="Google")
{
$xml=("http://news.google.com/news?ned=us&topic=h&output=rss");
}
elseif($q=="MSNBC")
{
$xml=("http://rss.msnbc.msn.com/id/3032091/device/rss/rss.xml");
}
$xmlDoc = new DOMDocument();
$xmlDoc>load($xml);
//get elements from "<channel>"
$channel=$xmlDoc>getElementsByTagName('channel')>item(0);
$channel_title = $channel>getElementsByTagName('title')
>item(0)>childNodes>item(0)>nodeValue;
$channel_link = $channel>getElementsByTagName('link')
>item(0)>childNodes>item(0)>nodeValue;](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-85-2048.jpg)
![The PHP Page
The server page called by the JavaScript code is a simple PHP file called "poll_vote.php".
<?php
$vote = $_REQUEST['vote'];
//get content of textfile
$filename = "poll_result.txt";
$content = file($filename);
//put content in array
$array = explode("||", $content[0]);
$yes = $array[0];
$no = $array[1];
if ($vote == 0)
{
$yes = $yes + 1;
}
if ($vote == 1)
{
$no = $no + 1;
}
//insert votes to txt file
$insertvote = $yes."||".$no;
$fp = fopen($filename,"w");
fputs($fp,$insertvote);
fclose($fp);
?>
<h2>Result:</h2>
<table>
<tr>
<td>Yes:</td>
<td>
<img src="poll.gif"
width='<?php echo(100*round($yes/($no+$yes),2)); ?>'
height='20'>
<?php echo(100*round($yes/($no+$yes),2)); ?>%
</td>
</tr>
<tr>
<td>No:</td>
<td>
<img src="poll.gif"
width='<?php echo(100*round($no/($no+$yes),2)); ?>'
height='20'>
<?php echo(100*round($no/($no+$yes),2)); ?>%
</td>
</tr>
</table>
The selected value is sent from the JavaScript and the following happens:
1. Get the content of the "poll_result.txt" file
2. Put the content of the file in variables and add one to the selected variable
3. Write the result to the "poll_result.txt" file
4. Output a graphical representation of the poll result](https://image.slidesharecdn.com/phptutorial-100423053259-phpapp02/75/Php-Tutorial-88-2048.jpg)
More Related Content
Php Tutorial
- 1. PHP Tutorial PHP Introduction PHP is a powerful tool for making dynamic and interactive Web pages. PHP is the widelyused, free, and efficient alternative to competitors such as Microsoft's ASP. PHP is a serverside scripting language. What You Should Already Know Before you continue you should have a basic understanding of the following: • HTML/XHTML • JavaScript What is PHP? • PHP stands for PHP: Hypertext Preprocessor • PHP is a serverside scripting language, like ASP • PHP scripts are executed on the server • PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.) • PHP is an open source software • PHP is free to download and use What is a PHP File? • PHP files can contain text, HTML tags and scripts • PHP files are returned to the browser as plain HTML • PHP files have a file extension of ".php", ".php3", or ".phtml" What is MySQL? • MySQL is a database server • MySQL is ideal for both small and large applications • MySQL supports standard SQL • MySQL compiles on a number of platforms • MySQL is free to download and use PHP + MySQL • PHP combined with MySQL are crossplatform (you can develop in Windows and serve on a Unix platform) Why PHP? • PHP runs on different platforms (Windows, Linux, Unix, etc.) • PHP is compatible with almost all servers used today (Apache, IIS, etc.) • PHP is FREE to download from the official PHP resource: www.php.net • PHP is easy to learn and runs efficiently on the server side Where to Start? To get access to a web server with PHP support, you can:
- 2. • Install Apache (or IIS) on your own server, install PHP, and MySQL • Or find a web hosting plan with PHP and MySQL support PHP Installation What do you Need? If your server supports PHP you don't need to do anything. Just create some .php files in your web directory, and the server will parse them for you. Because it is free, most web hosts offer PHP support. However, if your server does not support PHP, you must install PHP. Here is a link to a good tutorial from PHP.net on how to install PHP5: http://www.php.net/manual/en/install.php Download PHP Download PHP for free here: http://www.php.net/downloads.php Download MySQL Database Download MySQL for free here: http://www.mysql.com/downloads/index.html Download Apache Server Download Apache for free here: http://httpd.apache.org/download.cgi PHP Syntax PHP code is executed on the server, and the plain HTML result is sent to the browser. Basic PHP Syntax A PHP scripting block always starts with <?php and ends with ?>. A PHP scripting block can be placed anywhere in the document. On servers with shorthand support enabled you can start a scripting block with <? and end with ?>. For maximum compatibility, we recommend that you use the standard form (<?php) rather than the shorthand form. <?php ?> A PHP file normally contains HTML tags, just like an HTML file, and some PHP scripting code. Below, we have an example of a simple PHP script which sends the text "Hello World" to the browser: <html> <body> <?php echo "Hello World"; ?> </body> </html> Each code line in PHP must end with a semicolon. The semicolon is a separator and is used to distinguish one set of instructions from another. There are two basic statements to output text with PHP: echo and print. In the example above we have used the echo statement to output the text "Hello World".
- 3. Note: The file must have a .php extension. If the file has a .html extension, the PHP code will not be executed. Comments in PHP In PHP, we use // to make a singleline comment or /* and */ to make a large comment block. <html> <body> <?php //This is a comment /* This is a comment block */ ?> </body> </html> PHP Variables A variable is used to store information. Variables in PHP Variables are used for storing a values, like text strings, numbers or arrays. When a variable is declared, it can be used over and over again in your script. All variables in PHP start with a $ sign symbol. The correct way of declaring a variable in PHP: $var_name = value; New PHP programmers often forget the $ sign at the beginning of the variable. In that case it will not work. Let's try creating a variable containing a string, and a variable containing a number: <?php $txt="Hello World!"; $x=16; ?> PHP is a Loosely Typed Language In PHP, a variable does not need to be declared before adding a value to it. In the example above, you see that you do not have to tell PHP which data type the variable is. PHP automatically converts the variable to the correct data type, depending on its value. In a strongly typed programming language, you have to declare (define) the type and name of the variable before using it. In PHP, the variable is declared automatically when you use it. Naming Rules for Variables • A variable name must start with a letter or an underscore "_" • A variable name can only contain alphanumeric characters and underscores (az, AZ, 09, and _ ) • A variable name should not contain spaces. If a variable name is more than one word, it should be separated with an underscore ($my_string), or with capitalization ($myString)
- 4. PHP Operators This section lists the different operators used in PHP. Arithmetic Operators Operator Description Example Result + Addition x=2 4 x+2 Subtraction x=2 3 5x * Multiplication x=4 20 x*5 / Division 15/5 3 5/2 2.5 % Modulus (division remainder) 5%2 1 10%8 2 10%2 0 ++ Increment x=5 x=6 x++ Decrement x=5 x=4 x Assignment Operators Operator Example Is The Same As = x=y x=y += x+=y x=x+y = x=y x=xy *= x*=y x=x*y /= x/=y x=x/y .= x.=y x=x.y %= x%=y x=x%y Comparison Operators Operator Description Example == is equal to 5==8 returns false != is not equal 5!=8 returns true <> is not equal 5<>8 returns true > is greater than 5>8 returns false < is less than 5<8 returns true >= is greater than or equal to 5>=8 returns false <= is less than or equal to 5<=8 returns true Logical Operators Operator Description Example && and x=6 y=3 (x < 10 && y > 1) returns true || or x=6 y=3 (x==5 || y==5) returns false ! not x=6
- 5. y=3 !(x==y) returns true PHP If...Else Statements Conditional statements are used to perform different actions based on different conditions. Conditional Statements Very often when you write code, you want to perform different actions for different decisions. You can use conditional statements in your code to do this. In PHP we have the following conditional statements: • if statement use this statement to execute some code only if a specified condition is true • if...else statement use this statement to execute some code if a condition is true and another code if the condition is false • if...elseif....else statement use this statement to select one of several blocks of code to be executed • switch statement use this statement to select one of many blocks of code to be executed The if Statement Use the if statement to execute some code only if a specified condition is true. Syntax if (condition) code to be executed if condition is true; The following example will output "Have a nice weekend!" if the current day is Friday: <html> <body> <?php $d=date("D"); if ($d=="Fri") echo "Have a nice weekend!"; ?> </body> </html> Notice that there is no ..else.. in this syntax. The code is executed only if the specified condition is true. The if...else Statement Use the if....else statement to execute some code if a condition is true and another code if a condition is false. Syntax if (condition) code to be executed if condition is true; else code to be executed if condition is false;
- 6.
- 7.
- 8. What is an Array? A variable is a storage area holding a number or text. The problem is, a variable will hold only one value. An array is a special variable, which can store multiple values in one single variable. If you have a list of items (a list of car names, for example), storing the cars in single variables could look like this: $cars1="Saab"; $cars2="Volvo"; $cars3="BMW"; However, what if you want to loop through the cars and find a specific one? And what if you had not 3 cars, but 300? The best solution here is to use an array! An array can hold all your variable values under a single name. And you can access the values by referring to the array name. Each element in the array has its own index so that it can be easily accessed. In PHP, there are three kind of arrays: • Numeric array An array with a numeric index • Associative array An array where each ID key is associated with a value • Multidimensional array An array containing one or more arrays Numeric Arrays A numeric array stores each array element with a numeric index. There are two methods to create a numeric array. 1. In the following example the index are automatically assigned (the index starts at 0): $cars=array("Saab","Volvo","BMW","Toyota"); 2. In the following example we assign the index manually: $cars[0]="Saab"; $cars[1]="Volvo"; $cars[2]="BMW"; $cars[3]="Toyota"; Example In the following example you access the variable values by referring to the array name and index: <?php $cars[0]="Saab"; $cars[1]="Volvo"; $cars[2]="BMW"; $cars[3]="Toyota"; echo $cars[0] . " and " . $cars[1] . " are Swedish cars."; ?> The code above will output: Saab and Volvo are Swedish cars. Associative Arrays An associative array, each ID key is associated with a value. When storing data about specific named values, a numerical array is not always the best way to do it. With associative arrays we can use the values as keys and assign values to them. Example 1 In this example we use an array to assign ages to the different persons:
- 9.
- 10. [0] => Cleveland [1] => Loretta [2] => Junior ) ) Example 2 Lets try displaying a single value from the array above: echo "Is " . $families['Griffin'][2] . " a part of the Griffin family?"; The code above will output: Is Megan a part of the Griffin family? Complete PHP Array Reference For a complete reference of all array functions, go to our complete PHP Array Reference. The reference contains a brief description, and examples of use, for each function! PHP Array Functions PHP Array Introduction The array functions allow you to manipulate arrays. PHP supports both simple and multidimensional arrays. There are also specific functions for populating arrays from database queries. Installation The array functions are part of the PHP core. There is no installation needed to use these functions. PHP Array Functions PHP: indicates the earliest version of PHP that supports the function. Function Description PHP array() Creates an array 3 array_change_key_case() Returns an array with all keys in lowercase or uppercase 4 array_chunk() Splits an array into chunks of arrays 4 array_combine() Creates an array by using one array for keys and another for its values 5 array_count_values() Returns an array with the number of occurrences for each value 4 array_diff() Compares array values, and returns the differences 4 array_diff_assoc() Compares array keys and values, and returns the differences 4 array_diff_key() Compares array keys, and returns the differences 5 array_diff_uassoc() Compares array keys and values, with an additional usermade function 5 check, and returns the differences array_diff_ukey() Compares array keys, with an additional usermade function check, and 5 returns the differences array_fill() Fills an array with values 4 array_filter() Filters elements of an array using a usermade function 4 array_flip() Exchanges all keys with their associated values in an array 4 array_intersect() Compares array values, and returns the matches 4 array_intersect_assoc() Compares array keys and values, and returns the matches 4 array_intersect_key() Compares array keys, and returns the matches 5
- 11. array_intersect_uassoc() Compares array keys and values, with an additional usermade function 5 check, and returns the matches array_intersect_ukey() Compares array keys, with an additional usermade function check, and 5 returns the matches array_key_exists() Checks if the specified key exists in the array 4 array_keys() Returns all the keys of an array 4 array_map() Sends each value of an array to a usermade function, which returns new 4 values array_merge() Merges one or more arrays into one array 4 array_merge_recursive() Merges one or more arrays into one array 4 array_multisort() Sorts multiple or multidimensional arrays 4 array_pad() Inserts a specified number of items, with a specified value, to an array 4 array_pop() Deletes the last element of an array 4 array_product() Calculates the product of the values in an array 5 array_push() Inserts one or more elements to the end of an array 4 array_rand() Returns one or more random keys from an array 4 array_reduce() Returns an array as a string, using a userdefined function 4 array_reverse() Returns an array in the reverse order 4 array_search() Searches an array for a given value and returns the key 4 array_shift() Removes the first element from an array, and returns the value of the 4 removed element array_slice() Returns selected parts of an array 4 array_splice() Removes and replaces specified elements of an array 4 array_sum() Returns the sum of the values in an array 4 array_udiff() Compares array values in a usermade function and returns an array 5 array_udiff_assoc() Compares array keys, and compares array values in a usermade function, 5 and returns an array array_udiff_uassoc() Compares array keys and array values in usermade functions, and returns an 5 array array_uintersect() Compares array values in a usermade function and returns an array 5 array_uintersect_assoc() Compares array keys, and compares array values in a usermade function, 5 and returns an array array_uintersect_uassoc() Compares array keys and array values in usermade functions, and returns an 5 array array_unique() Removes duplicate values from an array 4 array_unshift() Adds one or more elements to the beginning of an array 4 array_values() Returns all the values of an array 4 array_walk() Applies a user function to every member of an array 3 array_walk_recursive() Applies a user function recursively to every member of an array 5 arsort() Sorts an array in reverse order and maintain index association 3 asort() Sorts an array and maintain index association 3 compact() Create array containing variables and their values 4 count() Counts elements in an array, or properties in an object 3 current() Returns the current element in an array 3 each() Returns the current key and value pair from an array 3 end() Sets the internal pointer of an array to its last element 3 extract() Imports variables into the current symbol table from an array 3 in_array() Checks if a specified value exists in an array 4 key() Fetches a key from an array 3 krsort() Sorts an array by key in reverse order 3 ksort() Sorts an array by key 3
- 12. list() Assigns variables as if they were an array 3 natcasesort() Sorts an array using a case insensitive "natural order" algorithm 4 natsort() Sorts an array using a "natural order" algorithm 4 next() Advance the internal array pointer of an array 3 pos() Alias of current() 3 prev() Rewinds the internal array pointer 3 range() Creates an array containing a range of elements 3 reset() Sets the internal pointer of an array to its first element 3 rsort() Sorts an array in reverse order 3 shuffle() Shuffles an array 3 sizeof() Alias of count() 3 sort() Sorts an array 3 uasort() Sorts an array with a userdefined function and maintain index association 3 uksort() Sorts an array by keys using a userdefined function 3 usort() Sorts an array by values using a userdefined function 3 PHP Array Constants PHP: indicates the earliest version of PHP that supports the constant. Constant Description PHP CASE_LOWER Used with array_change_key_case() to convert array keys to lower case CASE_UPPER Used with array_change_key_case() to convert array keys to upper case SORT_ASC Used with array_multisort() to sort in ascending order SORT_DESC Used with array_multisort() to sort in descending order SORT_REGULAR Used to compare items normally SORT_NUMERIC Used to compare items numerically SORT_STRING Used to compare items as strings SORT_LOCALE_STRING Used to compare items as strings, based on the current locale 4 COUNT_NORMAL COUNT_RECURSIVE EXTR_OVERWRITE EXTR_SKIP EXTR_PREFIX_SAME EXTR_PREFIX_ALL EXTR_PREFIX_INVALID EXTR_PREFIX_IF_EXISTS EXTR_IF_EXISTS EXTR_REFS PHP Looping While Loops Loops execute a block of code a specified number of times, or while a specified condition is true.
- 13. PHP Loops Often when you write code, you want the same block of code to run over and over again in a row. Instead of adding several almost equal lines in a script we can use loops to perform a task like this. In PHP, we have the following looping statements: • while loops through a block of code while a specified condition is true • do...while loops through a block of code once, and then repeats the loop as long as a specified condition is true • for loops through a block of code a specified number of times • foreach loops through a block of code for each element in an array The while Loop The while loop executes a block of code while a condition is true. Syntax while (condition) { code to be executed; } Example The example below defines a loop that starts with i=1. The loop will continue to run as long as i is less than, or equal to 5. i will increase by 1 each time the loop runs: <html> <body> <?php $i=1; while($i<=5) { echo "The number is " . $i . "<br />"; $i++; } ?> </body> </html> Output: The number is 1 The number is 2 The number is 3 The number is 4 The number is 5 The do...while Statement The do...while statement will always execute the block of code once, it will then check the condition, and repeat the loop while the condition is true. Syntax do { code to be executed;
- 14. } while (condition); Example The example below defines a loop that starts with i=1. It will then increment i with 1, and write some output. Then the condition is checked, and the loop will continue to run as long as i is less than, or equal to 5: <html> <body> <?php $i=1; do { $i++; echo "The number is " . $i . "<br />"; } while ($i<=5); ?> </body> </html> Output: The number is 2 The number is 3 The number is 4 The number is 5 The number is 6 The for loop and the foreach loop will be explained in the next chapter. PHP Looping For Loops Loops execute a block of code a specified number of times, or while a specified condition is true. The for Loop The for loop is used when you know in advance how many times the script should run. Syntax for (init; condition; increment) { code to be executed; } Parameters: • init: Mostly used to set a counter (but can be any code to be executed once at the beginning of the loop) • condition: Evaluated for each loop iteration. If it evaluates to TRUE, the loop continues. If it evaluates to FALSE, the loop ends. • increment: Mostly used to increment a counter (but can be any code to be executed at the end of the loop) Note: Each of the parameters above can be empty, or have multiple expressions (separated by commas). Example The example below defines a loop that starts with i=1. The loop will continue to run as long as i is less than, or equal to 5. i will increase by 1 each time the loop runs: <html>
- 15.
- 16. PHP Builtin Functions For a complete reference and examples of the builtin functions, please visit our PHP Reference. PHP Functions In this chapter we will show you how to create your own functions. To keep the script from being executed when the page loads, you can put it into a function. A function will be executed by a call to the function. You may call a function from anywhere within a page. Create a PHP Function A function will be executed by a call to the function. Syntax function functionName() { code to be executed; } PHP function guidelines: • Give the function a name that reflects what the function does • The function name can start with a letter or underscore (not a number) Example A simple function that writes my name when it is called: <html> <body> <?php function writeName() { echo "Kai Jim Refsnes"; } echo "My name is "; writeName(); ?> </body> </html> Output: My name is Kai Jim Refsnes PHP Functions Adding parameters To add more functionality to a function, we can add parameters. A parameter is just like a variable.
- 17.
- 18.
- 19.
- 20. The $_POST Function The builtin $_POST function is used to collect values from a form sent with method="post". Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send. Note: However, there is an 8 Mb max size for the POST method, by default (can be changed by setting the post_max_size in the php.ini file). Example <form action="welcome.php" method="post"> Name: <input type="text" name="fname" /> Age: <input type="text" name="age" /> <input type="submit" /> </form> When the user clicks the "Submit" button, the URL will look like this: http://www.w3schools.com/welcome.php The "welcome.php" file can now use the $_POST function to collect form data (the names of the form fields will automatically be the keys in the $_POST array): Welcome <?php echo $_POST["fname"]; ?>!<br /> You are <?php echo $_POST["age"]; ?> years old. When to use method="post"? Information sent from a form with the POST method is invisible to others and has no limits on the amount of information to send. However, because the variables are not displayed in the URL, it is not possible to bookmark the page. The PHP $_REQUEST Function The PHP builtin $_REQUEST function contains the contents of both $_GET, $_POST, and $_COOKIE. The $_REQUEST function can be used to collect form data sent with both the GET and POST methods. Example Welcome <?php echo $_REQUEST["fname"]; ?>!<br /> You are <?php echo $_REQUEST["age"]; ?> years old. PHP Advanced The PHP date() function is used to format a time and/or date. The PHP Date() Function The PHP date() function formats a timestamp to a more readable date and time. A timestamp is a sequence of characters, denoting the date and/or time at which a certain event occurred. Syntax date(format,timestamp) Parameter Description format Required. Specifies the format of the timestamp
- 21. timestamp Optional. Specifies a timestamp. Default is the current date and time PHP Date() Format the Date The required format parameter in the date() function specifies how to format the date/time. Here are some characters that can be used: • d Represents the day of the month (01 to 31) • m Represents a month (01 to 12) • Y Represents a year (in four digits) A list of all the characters that can be used in the format parameter, can be found in our PHP Date reference. Other characters, like"/", ".", or "" can also be inserted between the letters to add additional formatting: <?php echo date("Y/m/d") . "<br />"; echo date("Y.m.d") . "<br />"; echo date("Ymd") ?> The output of the code above could be something like this: 2009/05/11 2009.05.11 20090511 PHP Date() Adding a Timestamp The optional timestamp parameter in the date() function specifies a timestamp. If you do not specify a timestamp, the current date and time will be used. The mktime() function returns the Unix timestamp for a date. The Unix timestamp contains the number of seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time specified. Syntax for mktime() mktime(hour,minute,second,month,day,year,is_dst) To go one day in the future we simply add one to the day argument of mktime(): <?php $tomorrow = mktime(0,0,0,date("m"),date("d")+1,date("Y")); echo "Tomorrow is ".date("Y/m/d", $tomorrow); ?> The output of the code above could be something like this: Tomorrow is 2009/05/12 PHP Date / Time Functions PHP Date / Time Introduction The date/time functions allow you to extract and format the date and time on the server.
- 22. Note: These functions depend on the locale settings of the server! Installation The date/time functions are part of the PHP core. There is no installation needed to use these functions. Runtime Configuration The behavior of the date/time functions is affected by settings in php.ini. Date/Time configuration options: Name Default Description Changeable date.default_latitude "31.7667" Specifies the default latitude (available since PHP 5). PHP_INI_ALL This option is used by date_sunrise() and date_sunset() date.default_longitude "35.2333" Specifies the default longitude (available since PHP 5). PHP_INI_ALL This option is used by date_sunrise() and date_sunset() date.sunrise_zenith "90.83" Specifies the default sunrise zenith (available since PHP_INI_ALL PHP 5). This option is used by date_sunrise() and date_sunset() date.sunset_zenith "90.83" Specifies the default sunset zenith (available since PHP PHP_INI_ALL 5). This option is used by date_sunrise() and date_sunset() date.timezone "" Specifies the default timezone (available since PHP PHP_INI_ALL 5.1) PHP Date / Time Functions PHP: indicates the earliest version of PHP that supports the function. Function Description PHP checkdate() Validates a Gregorian date 3 date_default_timezone_get() Returns the default time zone 5 date_default_timezone_set() Sets the default time zone 5 date_sunrise() Returns the time of sunrise for a given day / location 5 date_sunset() Returns the time of sunset for a given day / location 5 date() Formats a local time/date 3 getdate() Returns an array that contains date and time information for a Unix 3 timestamp gettimeofday() Returns an array that contains current time information 3 gmdate() Formats a GMT/UTC date/time 3 gmmktime() Returns the Unix timestamp for a GMT date 3 gmstrftime() Formats a GMT/UTC time/date according to locale settings 3 idate() Formats a local time/date as integer 5 localtime() Returns an array that contains the time components of a Unix timestamp 4 microtime() Returns the microseconds for the current time 3 mktime() Returns the Unix timestamp for a date 3 strftime() Formats a local time/date according to locale settings 3 strptime() Parses a time/date generated with strftime() 5 strtotime() Parses an English textual date or time into a Unix timestamp 3
- 23. time() Returns the current time as a Unix timestamp 3 PHP Date / Time Constants PHP: indicates the earliest version of PHP that supports the constant. Constant Description PHP DATE_ATOM Atom (example: 20050815T16:13:03+0000) DATE_COOKIE HTTP Cookies (example: Sun, 14 Aug 2005 16:13:03 UTC) DATE_ISO8601 ISO8601 (example: 20050814T16:13:03+0000) DATE_RFC822 RFC 822 (example: Sun, 14 Aug 2005 16:13:03 UTC) DATE_RFC850 RFC 850 (example: Sunday, 14Aug05 16:13:03 UTC) DATE_RFC1036 RFC 1036 (example: Sunday, 14Aug05 16:13:03 UTC) DATE_RFC1123 RFC 1123 (example: Sun, 14 Aug 2005 16:13:03 UTC) DATE_RFC2822 RFC 2822 (Sun, 14 Aug 2005 16:13:03 +0000) DATE_RSS RSS (Sun, 14 Aug 2005 16:13:03 UTC) DATE_W3C World Wide Web Consortium (example: 20050814T16:13:03+0000) PHP Include File Server Side Includes (SSI) You can insert the content of one PHP file into another PHP file before the server executes it, with the include() or require() function. The two functions are identical in every way, except how they handle errors: • include() generates a warning, but the script will continue execution • require() generates a fatal error, and the script will stop These two functions are used to create functions, headers, footers, or elements that will be reused on multiple pages. Server side includes saves a lot of work. This means that you can create a standard header, footer, or menu file for all your web pages. When the header needs to be updated, you can only update the include file, or when you add a new page to your site, you can simply change the menu file (instead of updating the links on all your web pages). PHP include() Function The include() function takes all the content in a specified file and includes it in the current file. If an error occurs, the include() function generates a warning, but the script will continue execution. Example 1 Assume that you have a standard header file, called "header.php". To include the header file in a page, use the include() function: <html> <body> <?php include("header.php"); ?> <h1>Welcome to my home page!</h1> <p>Some text.</p>
- 24.
- 25.
- 26. </body> </html> The file may be opened in one of the following modes: Modes Description r Read only. Starts at the beginning of the file r+ Read/Write. Starts at the beginning of the file w Write only. Opens and clears the contents of file; or creates a new file if it doesn't exist w+ Read/Write. Opens and clears the contents of file; or creates a new file if it doesn't exist a Append. Opens and writes to the end of the file or creates a new file if it doesn't exist a+ Read/Append. Preserves file content by writing to the end of the file x Write only. Creates a new file. Returns FALSE and an error if file already exists x+ Read/Write. Creates a new file. Returns FALSE and an error if file already exists Note: If the fopen() function is unable to open the specified file, it returns 0 (false). Example The following example generates a message if the fopen() function is unable to open the specified file: <html> <body> <?php $file=fopen("welcome.txt","r") or exit("Unable to open file!"); ?> </body> </html> Closing a File The fclose() function is used to close an open file: <?php $file = fopen("test.txt","r"); //some code to be executed fclose($file); ?> Check Endoffile The feof() function checks if the "endoffile" (EOF) has been reached. The feof() function is useful for looping through data of unknown length. Note: You cannot read from files opened in w, a, and x mode! if (feof($file)) echo "End of file"; Reading a File Line by Line The fgets() function is used to read a single line from a file. Note: After a call to this function the file pointer has moved to the next line.
- 27. Example The example below reads a file line by line, until the end of file is reached: <?php $file = fopen("welcome.txt", "r") or exit("Unable to open file!"); //Output a line of the file until the end is reached while(!feof($file)) { echo fgets($file). "<br />"; } fclose($file); ?> Reading a File Character by Character The fgetc() function is used to read a single character from a file. Note: After a call to this function the file pointer moves to the next character. Example The example below reads a file character by character, until the end of file is reached: <?php $file=fopen("welcome.txt","r") or exit("Unable to open file!"); while (!feof($file)) { echo fgetc($file); } fclose($file); ?> PHP Filesystem Functions PHP Filesystem Introduction The filesystem functions allow you to access and manipulate the filesystem. Installation The filesystem functions are part of the PHP core. There is no installation needed to use these functions. Runtime Configuration The behavior of the filesystem functions is affected by settings in php.ini. Filesystem configuration options: Name Default Description Changeable allow_url_fopen "1" Allows fopen()type functions to work with URLs PHP_INI_SYSTEM (available since PHP 4.0.4)
- 28. user_agent NULL Defines the user agent for PHP to send (available since PHP_INI_ALL PHP 4.3) default_socket_timeout "60" Sets the default timeout, in seconds, for socket based PHP_INI_ALL streams (available since PHP 4.3) from "" Defines the anonymous FTP password (your email PHP_INI_ALL address) auto_detect_line_endings "0" When set to "1", PHP will examine the data read by PHP_INI_ALL fgets() and file() to see if it is using Unix, MSDos or Mac lineending characters (available since PHP 4.3) Unix / Windows Compatibility When specifying a path on Unix platforms, the forward slash (/) is used as directory separator. However, on Windows platforms, both forward slash (/) and backslash () can be used. PHP Filesystem Functions PHP: indicates the earliest version of PHP that supports the function. Function Description PHP basename() Returns the filename component of a path 3 chgrp() Changes the file group 3 chmod() Changes the file mode 3 chown() Changes the file owner 3 clearstatcache() Clears the file status cache 3 copy() Copies a file 3 delete() See unlink() or unset() dirname() Returns the directory name component of a path 3 disk_free_space() Returns the free space of a directory 4 disk_total_space() Returns the total size of a directory 4 diskfreespace() Alias of disk_free_space() 3 fclose() Closes an open file 3 feof() Tests for endoffile on an open file 3 fflush() Flushes buffered output to an open file 4 fgetc() Returns a character from an open file 3 fgetcsv() Parses a line from an open file, checking for CSV fields 3 fgets() Returns a line from an open file 3 fgetss() Returns a line, with HTML and PHP tags removed, from an open file 3 file() Reads a file into an array 3 file_exists() Checks whether or not a file or directory exists 3 file_get_contents() Reads a file into a string 4 file_put_contents Writes a string to a file 5 fileatime() Returns the last access time of a file 3 filectime() Returns the last change time of a file 3 filegroup() Returns the group ID of a file 3 fileinode() Returns the inode number of a file 3 filemtime() Returns the last modification time of a file 3 fileowner() Returns the user ID (owner) of a file 3 fileperms() Returns the permissions of a file 3
- 29. filesize() Returns the file size 3 filetype() Returns the file type 3 flock() Locks or releases a file 3 fnmatch() Matches a filename or string against a specified pattern 4 fopen() Opens a file or URL 3 fpassthru() Reads from an open file, until EOF, and writes the result to the output buffer 3 fputcsv() Formats a line as CSV and writes it to an open file 5 fputs() Alias of fwrite() 3 fread() Reads from an open file 3 fscanf() Parses input from an open file according to a specified format 4 fseek() Seeks in an open file 3 fstat() Returns information about an open file 4 ftell() Returns the current position in an open file 3 ftruncate() Truncates an open file to a specified length 4 fwrite() Writes to an open file 3 glob() Returns an array of filenames / directories matching a specified pattern 4 is_dir() Checks whether a file is a directory 3 is_executable() Checks whether a file is executable 3 is_file() Checks whether a file is a regular file 3 is_link() Checks whether a file is a link 3 is_readable() Checks whether a file is readable 3 is_uploaded_file() Checks whether a file was uploaded via HTTP POST 3 is_writable() Checks whether a file is writeable 4 is_writeable() Alias of is_writable() 3 link() Creates a hard link 3 linkinfo() Returns information about a hard link 3 lstat() Returns information about a file or symbolic link 3 mkdir() Creates a directory 3 move_uploaded_file() Moves an uploaded file to a new location 4 parse_ini_file() Parses a configuration file 4 pathinfo() Returns information about a file path 4 pclose() Closes a pipe opened by popen() 3 popen() Opens a pipe 3 readfile() Reads a file and writes it to the output buffer 3 readlink() Returns the target of a symbolic link 3 realpath() Returns the absolute pathname 4 rename() Renames a file or directory 3 rewind() Rewinds a file pointer 3 rmdir() Removes an empty directory 3 set_file_buffer() Sets the buffer size of an open file 3 stat() Returns information about a file 3 symlink() Creates a symbolic link 3 tempnam() Creates a unique temporary file 3 tmpfile() Creates a unique temporary file 3 touch() Sets access and modification time of a file 3 umask() Changes file permissions for files 3 unlink() Deletes a file 3
- 30. PHP Filesystem Constants PHP: indicates the earliest version of PHP that supports the constant. Constant Description PHP GLOB_BRACE GLOB_ONLYDIR GLOB_MARK GLOB_NOSORT GLOB_NOCHECK GLOB_NOESCAPE PATHINFO_DIRNAME PATHINFO_BASENAME PATHINFO_EXTENSION FILE_USE_INCLUDE_PATH FILE_APPEND FILE_IGNORE_NEW_LINES FILE_SKIP_EMPTY_LINES PHP File Upload With PHP, it is possible to upload files to the server. Create an UploadFile Form To allow users to upload files from a form can be very useful. Look at the following HTML form for uploading files: <html> <body> <form action="upload_file.php" method="post" enctype="multipart/formdata"> <label for="file">Filename:</label> <input type="file" name="file" id="file" /> <br /> <input type="submit" name="submit" value="Submit" /> </form> </body> </html> Notice the following about the HTML form above: • The enctype attribute of the <form> tag specifies which contenttype to use when submitting the form. "multipart/form data" is used when a form requires binary data, like the contents of a file, to be uploaded • The type="file" attribute of the <input> tag specifies that the input should be processed as a file. For example, when viewed in a browser, there will be a browsebutton next to the input field Note: Allowing users to upload files is a big security risk. Only permit trusted users to perform file uploads. Create The Upload Script The "upload_file.php" file contains the code for uploading a file:
- 31. <?php if ($_FILES["file"]["error"] > 0) { echo "Error: " . $_FILES["file"]["error"] . "<br />"; } else { echo "Upload: " . $_FILES["file"]["name"] . "<br />"; echo "Type: " . $_FILES["file"]["type"] . "<br />"; echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />"; echo "Stored in: " . $_FILES["file"]["tmp_name"]; } ?> By using the global PHP $_FILES array you can upload files from a client computer to the remote server. The first parameter is the form's input name and the second index can be either "name", "type", "size", "tmp_name" or "error". Like this: • $_FILES["file"]["name"] the name of the uploaded file • $_FILES["file"]["type"] the type of the uploaded file • $_FILES["file"]["size"] the size in bytes of the uploaded file • $_FILES["file"]["tmp_name"] the name of the temporary copy of the file stored on the server • $_FILES["file"]["error"] the error code resulting from the file upload This is a very simple way of uploading files. For security reasons, you should add restrictions on what the user is allowed to upload. Restrictions on Upload In this script we add some restrictions to the file upload. The user may only upload .gif or .jpeg files and the file size must be under 20 kb: <?php if ((($_FILES["file"]["type"] == "image/gif") || ($_FILES["file"]["type"] == "image/jpeg") || ($_FILES["file"]["type"] == "image/pjpeg")) && ($_FILES["file"]["size"] < 20000)) { if ($_FILES["file"]["error"] > 0) { echo "Error: " . $_FILES["file"]["error"] . "<br />"; } else { echo "Upload: " . $_FILES["file"]["name"] . "<br />"; echo "Type: " . $_FILES["file"]["type"] . "<br />"; echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />"; echo "Stored in: " . $_FILES["file"]["tmp_name"]; } } else { echo "Invalid file"; } ?> Note: For IE to recognize jpg files the type must be pjpeg, for FireFox it must be jpeg. Saving the Uploaded File The examples above create a temporary copy of the uploaded files in the PHP temp folder on the server. The temporary copied files disappears when the script ends. To store the uploaded file we need to copy it to a different location:
- 32.
- 33.
- 34.
- 35.
- 36. PHP Sending Emails PHP allows you to send emails directly from a script. The PHP mail() Function The PHP mail() function is used to send emails from inside a script. Syntax mail(to,subject,message,headers,parameters) Parameter Description to Required. Specifies the receiver / receivers of the email subject Required. Specifies the subject of the email. Note: This parameter cannot contain any newline characters message Required. Defines the message to be sent. Each line should be separated with a LF (n). Lines should not exceed 70 characters headers Optional. Specifies additional headers, like From, Cc, and Bcc. The additional headers should be separated with a CRLF (rn) parameters Optional. Specifies an additional parameter to the sendmail program Note: For the mail functions to be available, PHP requires an installed and working email system. The program to be used is defined by the configuration settings in the php.ini file. Read more in our PHP Mail reference. PHP Simple EMail The simplest way to send an email with PHP is to send a text email. In the example below we first declare the variables ($to, $subject, $message, $from, $headers), then we use the variables in the mail() function to send an email: <?php $to = "[email protected]"; $subject = "Test mail"; $message = "Hello! This is a simple email message."; $from = "[email protected]"; $headers = "From: $from"; mail($to,$subject,$message,$headers); echo "Mail Sent."; ?> PHP Mail Form With PHP, you can create a feedbackform on your website. The example below sends a text message to a specified e mail address: <html> <body> <?php if (isset($_REQUEST['email'])) //if "email" is filled out, send email { //send email $email = $_REQUEST['email'] ; $subject = $_REQUEST['subject'] ;
- 37. $message = $_REQUEST['message'] ; mail( "[email protected]", "Subject: $subject", $message, "From: $email" ); echo "Thank you for using our mail form"; } else //if "email" is not filled out, display the form { echo "<form method='post' action='mailform.php'> Email: <input name='email' type='text' /><br /> Subject: <input name='subject' type='text' /><br /> Message:<br /> <textarea name='message' rows='15' cols='40'> </textarea><br /> <input type='submit' /> </form>"; } ?> </body> </html> This is how the example above works: • First, check if the email input field is filled out • If it is not set (like when the page is first visited); output the HTML form • If it is set (after the form is filled out); send the email from the form • When submit is pressed after the form is filled out, the page reloads, sees that the email input is set, and sends the email Note: This is the simplest way to send email, but it is not secure. In the next chapter of this tutorial you can read more about vulnerabilities in email scripts, and how to validate user input to make it more secure. PHP Mail Reference For more information about the PHP mail() function, visit our PHP Mail Reference. PHP Mail Functions PHP Mail Introduction The mail() function allows you to send emails directly from a script. Requirements For the mail functions to be available, PHP requires an installed and working email system. The program to be used is defined by the configuration settings in the php.ini file. Installation The mail functions are part of the PHP core. There is no installation needed to use these functions.
- 38. Runtime Configuration The behavior of the mail functions is affected by settings in the php.ini file. Mail configuration options: Name Default Description Changeable SMTP "localhost" Windows only: The DNS name or IP address of the PHP_INI_ALL SMTP server smtp_port "25" Windows only: The SMTP port number. Available PHP_INI_ALL since PHP 4.3 sendmail_from NULL Windows only: Specifies the "from" address to be used PHP_INI_ALL in email sent from PHP sendmail_path NULL Unix systems only: Specifies where the sendmail PHP_INI_SYSTEM program can be found (usually /usr/sbin/sendmail or /usr/lib/sendmail) PHP Mail Functions PHP: indicates the earliest version of PHP that supports the function. Function Description PHP ezmlm_hash() Calculates the hash value needed by the EZMLM mailing list system 3 mail() Allows you to send emails directly from a script 3 PHP Mail Constants none PHP Secure Emails « Previous Next Chapter » There is a weakness in the PHP email script in the previous chapter. PHP Email Injections First, look at the PHP code from the previous chapter: <html> <body> <?php if (isset($_REQUEST['email'])) //if "email" is filled out, send email { //send email $email = $_REQUEST['email'] ; $subject = $_REQUEST['subject'] ; $message = $_REQUEST['message'] ; mail("[email protected]", "Subject: $subject", $message, "From: $email" );
- 39.
- 40. if ($mailcheck==FALSE) { echo "Invalid input"; } else {//send email $email = $_REQUEST['email'] ; $subject = $_REQUEST['subject'] ; $message = $_REQUEST['message'] ; mail("[email protected]", "Subject: $subject", $message, "From: $email" ); echo "Thank you for using our mail form"; } } else {//if "email" is not filled out, display the form echo "<form method='post' action='mailform.php'> Email: <input name='email' type='text' /><br /> Subject: <input name='subject' type='text' /><br /> Message:<br /> <textarea name='message' rows='15' cols='40'> </textarea><br /> <input type='submit' /> </form>"; } ?> </body> </html> In the code above we use PHP filters to validate input: • The FILTER_SANITIZE_EMAIL filter removes all illegal email characters from a string • The FILTER_VALIDATE_EMAIL filter validates value as an email address You can read more about filters in our PHP Filter chapter. PHP Error Handling The default error handling in PHP is very simple. An error message with filename, line number and a message describing the error is sent to the browser. PHP Error Handling When creating scripts and web applications, error handling is an important part. If your code lacks error checking code, your program may look very unprofessional and you may be open to security risks. This tutorial contains some of the most common error checking methods in PHP. We will show different error handling methods: • Simple "die()" statements • Custom errors and error triggers • Error reporting
- 41. Basic Error Handling: Using the die() function The first example shows a simple script that opens a text file: <?php $file=fopen("welcome.txt","r"); ?> If the file does not exist you might get an error like this: Warning: fopen(welcome.txt) [function.fopen]: failed to open stream: No such file or directory in C:webfoldertest.php on line 2 To avoid that the user gets an error message like the one above, we test if the file exist before we try to access it: <?php if(!file_exists("welcome.txt")) { die("File not found"); } else { $file=fopen("welcome.txt","r"); } ?> Now if the file does not exist you get an error like this: File not found The code above is more efficient than the earlier code, because it uses a simple error handling mechanism to stop the script after the error. However, simply stopping the script is not always the right way to go. Let's take a look at alternative PHP functions for handling errors. Creating a Custom Error Handler Creating a custom error handler is quite simple. We simply create a special function that can be called when an error occurs in PHP. This function must be able to handle a minimum of two parameters (error level and error message) but can accept up to five parameters (optionally: file, linenumber, and the error context): Syntax error_function(error_level,error_message, error_file,error_line,error_context) Parameter Description error_level Required. Specifies the error report level for the userdefined error. Must be a value number. See table below for possible error report levels error_message Required. Specifies the error message for the userdefined error error_file Optional. Specifies the filename in which the error occurred error_line Optional. Specifies the line number in which the error occurred error_context Optional. Specifies an array containing every variable, and their values, in use when the error occurred Error Report levels These error report levels are the different types of error the userdefined error handler can be used for: Value Constant Description 2 E_WARNING Nonfatal runtime errors. Execution of the script is not halted 8 E_NOTICE Runtime notices. The script found something that might be an error, but could also happen when running a script normally 256 E_USER_ERROR Fatal usergenerated error. This is like an E_ERROR set by the programmer using the PHP function trigger_error() 512 E_USER_WARNING Nonfatal usergenerated warning. This is like an E_WARNING set by the
- 42. programmer using the PHP function trigger_error() 1024 E_USER_NOTICE Usergenerated notice. This is like an E_NOTICE set by the programmer using the PHP function trigger_error() 4096 E_RECOVERABLE_ERROR Catchable fatal error. This is like an E_ERROR but can be caught by a user defined handle (see also set_error_handler()) 8191 E_ALL All errors and warnings, except level E_STRICT (E_STRICT will be part of E_ALL as of PHP 6.0) Now lets create a function to handle errors: function customError($errno, $errstr) { echo "<b>Error:</b> [$errno] $errstr<br />"; echo "Ending Script"; die(); } The code above is a simple error handling function. When it is triggered, it gets the error level and an error message. It then outputs the error level and message and terminates the script. Now that we have created an error handling function we need to decide when it should be triggered. Set Error Handler The default error handler for PHP is the built in error handler. We are going to make the function above the default error handler for the duration of the script. It is possible to change the error handler to apply for only some errors, that way the script can handle different errors in different ways. However, in this example we are going to use our custom error handler for all errors: set_error_handler("customError"); Since we want our custom function to handle all errors, the set_error_handler() only needed one parameter, a second parameter could be added to specify an error level. Example Testing the error handler by trying to output variable that does not exist: <?php //error handler function function customError($errno, $errstr) { echo "<b>Error:</b> [$errno] $errstr"; } //set error handler set_error_handler("customError"); //trigger error echo($test); ?> The output of the code above should be something like this: Error: [8] Undefined variable: test Trigger an Error In a script where users can input data it is useful to trigger errors when an illegal input occurs. In PHP, this is done by the trigger_error() function. Example In this example an error occurs if the "test" variable is bigger than "1":
- 43. <?php $test=2; if ($test>1) { trigger_error("Value must be 1 or below"); } ?> The output of the code above should be something like this: Notice: Value must be 1 or below in C:webfoldertest.php on line 6 An error can be triggered anywhere you wish in a script, and by adding a second parameter, you can specify what error level is triggered. Possible error types: • E_USER_ERROR Fatal usergenerated runtime error. Errors that can not be recovered from. Execution of the script is halted • E_USER_WARNING Nonfatal usergenerated runtime warning. Execution of the script is not halted • E_USER_NOTICE Default. Usergenerated runtime notice. The script found something that might be an error, but could also happen when running a script normally Example In this example an E_USER_WARNING occurs if the "test" variable is bigger than "1". If an E_USER_WARNING occurs we will use our custom error handler and end the script: <?php //error handler function function customError($errno, $errstr) { echo "<b>Error:</b> [$errno] $errstr<br />"; echo "Ending Script"; die(); } //set error handler set_error_handler("customError",E_USER_WARNING); //trigger error $test=2; if ($test>1) { trigger_error("Value must be 1 or below",E_USER_WARNING); } ?> The output of the code above should be something like this: Error: [512] Value must be 1 or below Ending Script Now that we have learned to create our own errors and how to trigger them, lets take a look at error logging. Error Logging By default, PHP sends an error log to the servers logging system or a file, depending on how the error_log configuration is set in the php.ini file. By using the error_log() function you can send error logs to a specified file or a remote destination. Sending errors messages to yourself by email can be a good way of getting notified of specific errors. Send an Error Message by EMail In the example below we will send an email with an error message and end the script, if a specific error occurs: <?php //error handler function
- 44. function customError($errno, $errstr) { echo "<b>Error:</b> [$errno] $errstr<br />"; echo "Webmaster has been notified"; error_log("Error: [$errno] $errstr",1, "[email protected]","From: [email protected]"); } //set error handler set_error_handler("customError",E_USER_WARNING); //trigger error $test=2; if ($test>1) { trigger_error("Value must be 1 or below",E_USER_WARNING); } ?> The output of the code above should be something like this: Error: [512] Value must be 1 or below Webmaster has been notified And the mail received from the code above looks like this: Error: [512] Value must be 1 or below This should not be used with all errors. Regular errors should be logged on the server using the default PHP logging system. PHP Exception Handling Exceptions are used to change the normal flow of a script if a specified error occurs What is an Exception With PHP 5 came a new object oriented way of dealing with errors. Exception handling is used to change the normal flow of the code execution if a specified error (exceptional) condition occurs. This condition is called an exception. This is what normally happens when an exception is triggered: • The current code state is saved • The code execution will switch to a predefined (custom) exception handler function • Depending on the situation, the handler may then resume the execution from the saved code state, terminate the script execution or continue the script from a different location in the code We will show different error handling methods: • Basic use of Exceptions • Creating a custom exception handler • Multiple exceptions • Rethrowing an exception • Setting a top level exception handler Note: Exceptions should only be used with error conditions, and should not be used to jump to another place in the code at a specified point.
- 45. Basic Use of Exceptions When an exception is thrown, the code following it will not be executed, and PHP will try to find the matching "catch" block. If an exception is not caught, a fatal error will be issued with an "Uncaught Exception" message. Lets try to throw an exception without catching it: <?php //create function with an exception function checkNum($number) { if($number>1) { throw new Exception("Value must be 1 or below"); } return true; } //trigger exception checkNum(2); ?> The code above will get an error like this: Fatal error: Uncaught exception 'Exception' with message 'Value must be 1 or below' in C:webfoldertest.php:6 Stack trace: #0 C:webfoldertest.php(12): checkNum(28) #1 {main} thrown in C:webfoldertest.php on line 6 Try, throw and catch To avoid the error from the example above, we need to create the proper code to handle an exception. Proper exception code should include: 1. Try A function using an exception should be in a "try" block. If the exception does not trigger, the code will continue as normal. However if the exception triggers, an exception is "thrown" 2. Throw This is how you trigger an exception. Each "throw" must have at least one "catch" 3. Catch A "catch" block retrieves an exception and creates an object containing the exception information Lets try to trigger an exception with valid code: <?php //create function with an exception function checkNum($number) { if($number>1) { throw new Exception("Value must be 1 or below"); } return true; } //trigger exception in a "try" block try { checkNum(2); //If the exception is thrown, this text will not be shown echo 'If you see this, the number is 1 or below'; } //catch exception catch(Exception $e) { echo 'Message: ' .$e>getMessage(); } ?> The code above will get an error like this: Message: Value must be 1 or below
- 46. Example explained: The code above throws an exception and catches it: 1. The checkNum() function is created. It checks if a number is greater than 1. If it is, an exception is thrown 2. The checkNum() function is called in a "try" block 3. The exception within the checkNum() function is thrown 4. The "catch" block retrives the exception and creates an object ($e) containing the exception information 5. The error message from the exception is echoed by calling $e>getMessage() from the exception object However, one way to get around the "every throw must have a catch" rule is to set a top level exception handler to handle errors that slip through. Creating a Custom Exception Class Creating a custom exception handler is quite simple. We simply create a special class with functions that can be called when an exception occurs in PHP. The class must be an extension of the exception class. The custom exception class inherits the properties from PHP's exception class and you can add custom functions to it. Lets create an exception class: <?php class customException extends Exception { public function errorMessage() { //error message $errorMsg = 'Error on line '.$this>getLine().' in '.$this>getFile() .': <b>'.$this>getMessage().'</b> is not a valid EMail address'; return $errorMsg; } } $email = "[email protected]"; try { //check if if(filter_var($email, FILTER_VALIDATE_EMAIL) === FALSE) { //throw exception if email is not valid throw new customException($email); } } catch (customException $e) { //display custom message echo $e>errorMessage(); } ?> The new class is a copy of the old exception class with an addition of the errorMessage() function. Since it is a copy of the old class, and it inherits the properties and methods from the old class, we can use the exception class methods like getLine() and getFile() and getMessage(). Example explained: The code above throws an exception and catches it with a custom exception class: 1. The customException() class is created as an extension of the old exception class. This way it inherits all methods and properties from the old exception class 2. The errorMessage() function is created. This function returns an error message if an email address is invalid 3. The $email variable is set to a string that is not a valid email address 4. The "try" block is executed and an exception is thrown since the email address is invalid 5. The "catch" block catches the exception and displays the error message
- 47. Multiple Exceptions It is possible for a script to use multiple exceptions to check for multiple conditions. It is possible to use several if..else blocks, a switch, or nest multiple exceptions. These exceptions can use different exception classes and return different error messages: <?php class customException extends Exception { public function errorMessage() { //error message $errorMsg = 'Error on line '.$this>getLine().' in '.$this>getFile() .': <b>'.$this>getMessage().'</b> is not a valid EMail address'; return $errorMsg; } } $email = "[email protected]"; try { //check if if(filter_var($email, FILTER_VALIDATE_EMAIL) === FALSE) { //throw exception if email is not valid throw new customException($email); } //check for "example" in mail address if(strpos($email, "example") !== FALSE) { throw new Exception("$email is an example email"); } } catch (customException $e) { echo $e>errorMessage(); } catch(Exception $e) { echo $e>getMessage(); } ?> Example explained: The code above tests two conditions and throws an exception if any of the conditions are not met: 1. The customException() class is created as an extension of the old exception class. This way it inherits all methods and properties from the old exception class 2. The errorMessage() function is created. This function returns an error message if an email address is invalid 3. The $email variable is set to a string that is a valid email address, but contains the string "example" 4. The "try" block is executed and an exception is not thrown on the first condition 5. The second condition triggers an exception since the email contains the string "example" 6. The "catch" block catches the exception and displays the correct error message If there was no customException catch, only the base exception catch, the exception would be handled there
- 48. Rethrowing Exceptions Sometimes, when an exception is thrown, you may wish to handle it differently than the standard way. It is possible to throw an exception a second time within a "catch" block. A script should hide system errors from users. System errors may be important for the coder, but is of no interest to the user. To make things easier for the user you can rethrow the exception with a user friendly message: <?php class customException extends Exception { public function errorMessage() { //error message $errorMsg = $this>getMessage().' is not a valid EMail address.'; return $errorMsg; } } $email = "[email protected]"; try { try { //check for "example" in mail address if(strpos($email, "example") !== FALSE) { //throw exception if email is not valid throw new Exception($email); } } catch(Exception $e) { //rethrow exception throw new customException($email); } } catch (customException $e) { //display custom message echo $e>errorMessage(); } ?> Example explained: The code above tests if the emailaddress contains the string "example" in it, if it does, the exception is rethrown: 1. The customException() class is created as an extension of the old exception class. This way it inherits all methods and properties from the old exception class 2. The errorMessage() function is created. This function returns an error message if an email address is invalid 3. The $email variable is set to a string that is a valid email address, but contains the string "example" 4. The "try" block contains another "try" block to make it possible to rethrow the exception 5. The exception is triggered since the email contains the string "example" 6. The "catch" block catches the exception and rethrows a "customException" 7. The "customException" is caught and displays an error message If the exception is not caught in its current "try" block, it will search for a catch block on "higher levels". Set a Top Level Exception Handler The set_exception_handler() function sets a userdefined function to handle all uncaught exceptions. <?php function myException($exception)
- 49. { echo "<b>Exception:</b> " , $exception>getMessage(); } set_exception_handler('myException'); throw new Exception('Uncaught Exception occurred'); ?> The output of the code above should be something like this: Exception: Uncaught Exception occurred In the code above there was no "catch" block. Instead, the top level exception handler triggered. This function should be used to catch uncaught exceptions. Rules for exceptions • Code may be surrounded in a try block, to help catch potential exceptions • Each try block or "throw" must have at least one corresponding catch block • Multiple catch blocks can be used to catch different classes of exceptions • Exceptions can be thrown (or rethrown) in a catch block within a try block A simple rule: If you throw something, you have to catch it. PHP Filter PHP filters are used to validate and filter data coming from insecure sources, like user input. What is a PHP Filter? A PHP filter is used to validate and filter data coming from insecure sources. To test, validate and filter user input or custom data is an important part of any web application. The PHP filter extension is designed to make data filtering easier and quicker. Why use a Filter? Almost all web applications depend on external input. Usually this comes from a user or another application (like a web service). By using filters you can be sure your application gets the correct input type. You should always filter all external data! Input filtering is one of the most important application security issues. What is external data? • Input data from a form • Cookies • Web services data • Server variables • Database query results
- 50. Functions and Filters To filter a variable, use one of the following filter functions: • filter_var() Filters a single variable with a specified filter • filter_var_array() Filter several variables with the same or different filters • filter_input Get one input variable and filter it • filter_input_array Get several input variables and filter them with the same or different filters In the example below, we validate an integer using the filter_var() function: <?php $int = 123; if(!filter_var($int, FILTER_VALIDATE_INT)) { echo("Integer is not valid"); } else { echo("Integer is valid"); } ?> The code above uses the "FILTER_VALIDATE_INT" filter to filter the variable. Since the integer is valid, the output of the code above will be: "Integer is valid". If we try with a variable that is not an integer (like "123abc"), the output will be: "Integer is not valid". For a complete list of functions and filters, visit our PHP Filter Reference. Validating and Sanitizing There are two kinds of filters: Validating filters: • Are used to validate user input • Strict format rules (like URL or EMail validating) • Returns the expected type on success or FALSE on failure Sanitizing filters: • Are used to allow or disallow specified characters in a string • No data format rules • Always return the string Options and Flags Options and flags are used to add additional filtering options to the specified filters. Different filters have different options and flags. In the example below, we validate an integer using the filter_var() and the "min_range" and "max_range" options: <?php $var=300; $int_options = array( "options"=>array ( "min_range"=>0, "max_range"=>256
- 51. ) ); if(!filter_var($var, FILTER_VALIDATE_INT, $int_options)) { echo("Integer is not valid"); } else { echo("Integer is valid"); } ?> Like the code above, options must be put in an associative array with the name "options". If a flag is used it does not need to be in an array. Since the integer is "300" it is not in the specified range, and the output of the code above will be: "Integer is not valid". For a complete list of functions and filters, visit our PHP Filter Reference. Check each filter to see what options and flags are available. Validate Input Let's try validating input from a form. The first thing we need to do is to confirm that the input data we are looking for exists. Then we filter the input data using the filter_input() function. In the example below, the input variable "email" is sent to the PHP page: <?php if(!filter_has_var(INPUT_GET, "email")) { echo("Input type does not exist"); } else { if (!filter_input(INPUT_GET, "email", FILTER_VALIDATE_EMAIL)) { echo "EMail is not valid"; } else { echo "EMail is valid"; } } ?> Example Explained The example above has an input (email) sent to it using the "GET" method: 1. Check if an "email" input variable of the "GET" type exist 2. If the input variable exists, check if it is a valid email address Sanitize Input Let's try cleaning up an URL sent from a form. First we confirm that the input data we are looking for exists. Then we sanitize the input data using the filter_input() function. In the example below, the input variable "url" is sent to the PHP page: <?php
- 52. if(!filter_has_var(INPUT_POST, "url")) { echo("Input type does not exist"); } else { $url = filter_input(INPUT_POST, "url", FILTER_SANITIZE_URL); } ?> Example Explained The example above has an input (url) sent to it using the "POST" method: 1. Check if the "url" input of the "POST" type exists 2. If the input variable exists, sanitize (take away invalid characters) and store it in the $url variable If the input variable is a string like this "http://www.W3ååSchøøools.com/", the $url variable after the sanitizing will look like this: http://www.W3Schools.com/ Filter Multiple Inputs A form almost always consist of more than one input field. To avoid calling the filter_var or filter_input functions over and over, we can use the filter_var_array or the filter_input_array functions. In this example we use the filter_input_array() function to filter three GET variables. The received GET variables is a name, an age and an email address: <?php $filters = array ( "name" => array ( "filter"=>FILTER_SANITIZE_STRING ), "age" => array ( "filter"=>FILTER_VALIDATE_INT, "options"=>array ( "min_range"=>1, "max_range"=>120 ) ), "email"=> FILTER_VALIDATE_EMAIL, ); $result = filter_input_array(INPUT_GET, $filters); if (!$result["age"]) { echo("Age must be a number between 1 and 120.<br />"); } elseif(!$result["email"]) { echo("EMail is not valid.<br />"); } else { echo("User input is valid"); } ?>
- 53. Example Explained The example above has three inputs (name, age and email) sent to it using the "GET" method: 1. Set an array containing the name of input variables and the filters used on the specified input variables 2. Call the filter_input_array() function with the GET input variables and the array we just set 3. Check the "age" and "email" variables in the $result variable for invalid inputs. (If any of the input variables are invalid, that input variable will be FALSE after the filter_input_array() function) The second parameter of the filter_input_array() function can be an array or a single filter ID. If the parameter is a single filter ID all values in the input array are filtered by the specified filter. If the parameter is an array it must follow these rules: • Must be an associative array containing an input variable as an array key (like the "age" input variable) • The array value must be a filter ID or an array specifying the filter, flags and options Using Filter Callback It is possible to call a user defined function and use it as a filter using the FILTER_CALLBACK filter. This way, we have full control of the data filtering. You can create your own user defined function or use an existing PHP function The function you wish to use to filter is specified the same way as an option is specified. In an associative array with the name "options" In the example below, we use a user created function to convert all "_" to whitespaces: <?php function convertSpace($string) { return str_replace("_", " ", $string); } $string = "Peter_is_a_great_guy!"; echo filter_var($string, FILTER_CALLBACK, array("options"=>"convertSpace")); ?> The result from the code above should look like this: Peter is a great guy! Example Explained The example above converts all "_" to whitespaces: 1. Create a function to replace "_" to whitespaces 2. Call the filter_var() function with the FILTER_CALLBACK filter and an array containing our function PHP Database PHP MySQL Introduction MySQL is the most popular opensource database system. What is MySQL? MySQL is a database. The data in MySQL is stored in database objects called tables.
- 54. A table is a collections of related data entries and it consists of columns and rows. Databases are useful when storing information categorically. A company may have a database with the following tables: "Employees", "Products", "Customers" and "Orders". Database Tables A database most often contains one or more tables. Each table is identified by a name (e.g. "Customers" or "Orders"). Tables contain records (rows) with data. Below is an example of a table called "Persons": LastName FirstName Address City Hansen Ola Timoteivn 10 Sandnes Svendson Tove Borgvn 23 Sandnes Pettersen Kari Storgt 20 Stavanger The table above contains three records (one for each person) and four columns (LastName, FirstName, Address, and City). Queries A query is a question or a request. With MySQL, we can query a database for specific information and have a recordset returned. Look at the following query: SELECT LastName FROM Persons The query above selects all the data in the "LastName" column from the "Persons" table, and will return a recordset like this: LastName Hansen Svendson Pettersen Download MySQL Database If you don't have a PHP server with a MySQL Database, you can download MySQL for free here: http://www.mysql.com/downloads/index.html Facts About MySQL Database One great thing about MySQL is that it can be scaled down to support embedded database applications. Perhaps it is because of this reputation that many people believe that MySQL can only handle small to mediumsized systems. The truth is that MySQL is the defacto standard database for web sites that support huge volumes of both data and end users (like Friendster, Yahoo, Google). Look at http://www.mysql.com/customers/ for an overview of companies using MySQL. PHP MySQL Connect to a Database The free MySQL database is very often used with PHP.
- 55. Create a Connection to a MySQL Database Before you can access data in a database, you must create a connection to the database. In PHP, this is done with the mysql_connect() function. Syntax mysql_connect(servername,username,password); Parameter Description servername Optional. Specifies the server to connect to. Default value is "localhost:3306" username Optional. Specifies the username to log in with. Default value is the name of the user that owns the server process password Optional. Specifies the password to log in with. Default is "" Note: There are more available parameters, but the ones listed above are the most important. Visit our full PHP MySQL Reference for more details. Example In the following example we store the connection in a variable ($con) for later use in the script. The "die" part will be executed if the connection fails: <?php $con = mysql_connect("localhost","peter","abc123"); if (!$con) { die('Could not connect: ' . mysql_error()); } // some code ?> Closing a Connection The connection will be closed automatically when the script ends. To close the connection before, use the mysql_close() function: <?php $con = mysql_connect("localhost","peter","abc123"); if (!$con) { die('Could not connect: ' . mysql_error()); } // some code mysql_close($con); ?> PHP MySQL Create Database and Tables A database holds one or multiple tables. Create a Database The CREATE DATABASE statement is used to create a database in MySQL.
- 56.
- 57.
- 58.
- 59.
- 60. The example above stores the data returned by the mysql_query() function in the $result variable. Next, we use the mysql_fetch_array() function to return the first row from the recordset as an array. Each call to mysql_fetch_array() returns the next row in the recordset. The while loop loops through all the records in the recordset. To print the value of each row, we use the PHP $row variable ($row['FirstName'] and $row['LastName']). The output of the code above will be: Peter Griffin Glenn Quagmire Display the Result in an HTML Table The following example selects the same data as the example above, but will display the data in an HTML table: <?php $con = mysql_connect("localhost","peter","abc123"); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("my_db", $con); $result = mysql_query("SELECT * FROM Persons"); echo "<table border='1'> <tr> <th>Firstname</th> <th>Lastname</th> </tr>"; while($row = mysql_fetch_array($result)) { echo "<tr>"; echo "<td>" . $row['FirstName'] . "</td>"; echo "<td>" . $row['LastName'] . "</td>"; echo "</tr>"; } echo "</table>"; mysql_close($con); ?> The output of the code above will be: Firstname Lastname Glenn Quagmire Peter Griffin PHP MySQL The Where Clause The WHERE clause is used to filter records. The WHERE clause The WHERE clause is used to extract only those records that fulfill a specified criterion.
- 61.
- 62.
- 63. FirstName LastName Age Peter Griffin 35 Glenn Quagmire 33 The following example updates some data in the "Persons" table: <?php $con = mysql_connect("localhost","peter","abc123"); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("my_db", $con); mysql_query("UPDATE Persons SET Age = '36' WHERE FirstName = 'Peter' AND LastName = 'Griffin'"); mysql_close($con); ?> After the update, the "Persons" table will look like this: FirstName LastName Age Peter Griffin 36 Glenn Quagmire 33 PHP MySQL Delete The DELETE statement is used to delete records in a table. Delete Data In a Database The DELETE FROM statement is used to delete records from a database table. Syntax DELETE FROM table_name WHERE some_column = some_value Note: Notice the WHERE clause in the DELETE syntax. The WHERE clause specifies which record or records that should be deleted. If you omit the WHERE clause, all records will be deleted! To learn more about SQL, please visit our SQL tutorial. To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection. Example Look at the following "Persons" table: FirstName LastName Age Peter Griffin 35 Glenn Quagmire 33 The following example deletes all the records in the "Persons" table where LastName='Griffin': <?php $con = mysql_connect("localhost","peter","abc123"); if (!$con) {
- 64. die('Could not connect: ' . mysql_error()); } mysql_select_db("my_db", $con); mysql_query("DELETE FROM Persons WHERE LastName='Griffin'"); mysql_close($con); ?> After the deletion, the table will look like this: FirstName LastName Age Glenn Quagmire 33 PHP Database ODBC ODBC is an Application Programming Interface (API) that allows you to connect to a data source (e.g. an MS Access database). Create an ODBC Connection With an ODBC connection, you can connect to any database, on any computer in your network, as long as an ODBC connection is available. Here is how to create an ODBC connection to a MS Access Database: 1. Open the Administrative Tools icon in your Control Panel. 2. Doubleclick on the Data Sources (ODBC) icon inside. 3. Choose the System DSN tab. 4. Click on Add in the System DSN tab. 5. Select the Microsoft Access Driver. Click Finish. 6. In the next screen, click Select to locate the database. 7. Give the database a Data Source Name (DSN). 8. Click OK. Note that this configuration has to be done on the computer where your web site is located. If you are running Internet Information Server (IIS) on your own computer, the instructions above will work, but if your web site is located on a remote server, you have to have physical access to that server, or ask your web host to to set up a DSN for you to use. Connecting to an ODBC The odbc_connect() function is used to connect to an ODBC data source. The function takes four parameters: the data source name, username, password, and an optional cursor type. The odbc_exec() function is used to execute an SQL statement. Example The following example creates a connection to a DSN called northwind, with no username and no password. It then creates an SQL and executes it: $conn=odbc_connect('northwind','',''); $sql="SELECT * FROM customers"; $rs=odbc_exec($conn,$sql);
- 65.
- 66. PHP XML PHP XML Expat Parser The builtin Expat parser makes it possible to process XML documents in PHP. What is XML? XML is used to describe data and to focus on what data is. An XML file describes the structure of the data. In XML, no tags are predefined. You must define your own tags. If you want to learn more about XML, please visit our XML tutorial. What is Expat? To read and update create and manipulate an XML document, you will need an XML parser. There are two basic types of XML parsers: • Treebased parser: This parser transforms an XML document into a tree structure. It analyzes the whole document, and provides access to the tree elements. e.g. the Document Object Model (DOM) • Eventbased parser: Views an XML document as a series of events. When a specific event occurs, it calls a function to handle it The Expat parser is an eventbased parser. Eventbased parsers focus on the content of the XML documents, not their structure. Because of this, eventbased parsers can access data faster than treebased parsers. Look at the following XML fraction: <from>Jani</from> An eventbased parser reports the XML above as a series of three events: • Start element: from • Start CDATA section, value: Jani • Close element: from The XML example above contains wellformed XML. However, the example is not valid XML, because there is no Document Type Definition (DTD) associated with it. However, this makes no difference when using the Expat parser. Expat is a nonvalidating parser, and ignores any DTDs. As an eventbased, nonvalidating XML parser, Expat is fast and small, and a perfect match for PHP web applications. Note: XML documents must be wellformed or Expat will generate an error. Installation The XML Expat parser functions are part of the PHP core. There is no installation needed to use these functions. An XML File The XML file below will be used in our example:
- 67.
- 68. { xml_parse($parser,$data,feof($fp)) or die (sprintf("XML Error: %s at line %d", xml_error_string(xml_get_error_code($parser)), xml_get_current_line_number($parser))); } //Free the XML parser xml_parser_free($parser); ?> The output of the code above will be: Note To: Tove From: Jani Heading: Reminder Message: Don't forget me this weekend! How it works: 1. Initialize the XML parser with the xml_parser_create() function 2. Create functions to use with the different event handlers 3. Add the xml_set_element_handler() function to specify which function will be executed when the parser encounters the opening and closing tags 4. Add the xml_set_character_data_handler() function to specify which function will execute when the parser encounters character data 5. Parse the file "test.xml" with the xml_parse() function 6. In case of an error, add xml_error_string() function to convert an XML error to a textual description 7. Call the xml_parser_free() function to release the memory allocated with the xml_parser_create() function More PHP Expat Parser For more information about the PHP Expat functions, visit our PHP XML Parser Reference. PHP XML DOM The builtin DOM parser makes it possible to process XML documents in PHP. What is DOM? The W3C DOM provides a standard set of objects for HTML and XML documents, and a standard interface for accessing and manipulating them. The W3C DOM is separated into different parts (Core, XML, and HTML) and different levels (DOM Level 1/2/3): * Core DOM defines a standard set of objects for any structured document * XML DOM defines a standard set of objects for XML documents * HTML DOM defines a standard set of objects for HTML documents If you want to learn more about the XML DOM, please visit our XML DOM tutorial. XML Parsing To read and update create and manipulate an XML document, you will need an XML parser. There are two basic types of XML parsers:
- 69. • Treebased parser: This parser transforms an XML document into a tree structure. It analyzes the whole document, and provides access to the tree elements • Eventbased parser: Views an XML document as a series of events. When a specific event occurs, it calls a function to handle it The DOM parser is an treebased parser. Look at the following XML document fraction: <?xml version="1.0" encoding="ISO88591"?> <from>Jani</from> The XML DOM sees the XML above as a tree structure: • Level 1: XML Document • Level 2: Root element: <from> • Level 3: Text element: "Jani" Installation The DOM XML parser functions are part of the PHP core. There is no installation needed to use these functions. An XML File The XML file below will be used in our example: <?xml version="1.0" encoding="ISO88591"?> <note> <to>Tove</to> <from>Jani</from> <heading>Reminder</heading> <body>Don't forget me this weekend!</body> </note> Load and Output XML We want to initialize the XML parser, load the xml, and output it: Example <?php $xmlDoc = new DOMDocument(); $xmlDoc>load("note.xml"); print $xmlDoc>saveXML(); ?> The output of the code above will be: Tove Jani Reminder Don't forget me this weekend! If you select "View source" in the browser window, you will see the following HTML: <?xml version="1.0" encoding="ISO88591"?> <note> <to>Tove</to> <from>Jani</from> <heading>Reminder</heading> <body>Don't forget me this weekend!</body> </note> The example above creates a DOMDocumentObject and loads the XML from "note.xml" into it.
- 70. Then the saveXML() function puts the internal XML document into a string, so we can output it. Looping through XML We want to initialize the XML parser, load the XML, and loop through all elements of the <note> element: Example <?php $xmlDoc = new DOMDocument(); $xmlDoc>load("note.xml"); $x = $xmlDoc>documentElement; foreach ($x>childNodes AS $item) { print $item>nodeName . " = " . $item>nodeValue . "<br />"; } ?> The output of the code above will be: #text = to = Tove #text = from = Jani #text = heading = Reminder #text = body = Don't forget me this weekend! #text = In the example above you see that there are empty text nodes between each element. When XML generates, it often contains whitespaces between the nodes. The XML DOM parser treats these as ordinary elements, and if you are not aware of them, they sometimes cause problems. If you want to learn more about the XML DOM, please visit our XML DOM tutorial. PHP SimpleXML SimpleXML handles the most common XML tasks and leaves the rest for other extensions. What is SimpleXML? SimpleXML is new in PHP 5. It is an easy way of getting an element's attributes and text, if you know the XML document's layout. Compared to DOM or the Expat parser, SimpleXML just takes a few lines of code to read text data from an element. SimpleXML converts the XML document into an object, like this: • Elements Are converted to single attributes of the SimpleXMLElement object. When there's more than one element on one level, they're placed inside an array • Attributes Are accessed using associative arrays, where an index corresponds to the attribute name • Element Data Text data from elements are converted to strings. If an element has more than one text node, they will be arranged in the order they are found SimpleXML is fast and easy to use when performing basic tasks like: • Reading XML files
- 71. • Extracting data from XML strings • Editing text nodes or attributes However, when dealing with advanced XML, like namespaces, you are better off using the Expat parser or the XML DOM. Installation As of PHP 5.0, the SimpleXML functions are part of the PHP core. There is no installation needed to use these functions. Using SimpleXML Below is an XML file: <?xml version="1.0" encoding="ISO88591"?> <note> <to>Tove</to> <from>Jani</from> <heading>Reminder</heading> <body>Don't forget me this weekend!</body> </note> We want to output the element names and data from the XML file above. Here's what to do: 1. Load the XML file 2. Get the name of the first element 3. Create a loop that will trigger on each child node, using the children() function 4. Output the element name and data for each child node Example <?php $xml = simplexml_load_file("test.xml"); echo $xml>getName() . "<br />"; foreach($xml>children() as $child) { echo $child>getName() . ": " . $child . "<br />"; } ?> The output of the code above will be: note to: Tove from: Jani heading: Reminder body: Don't forget me this weekend! More PHP SimpleXML For more information about the PHP SimpleXML functions, visit our PHP SimpleXML Reference. PHP and AJAX AJAX Introduction
- 72.
- 73. AJAX is Based on Internet Standards AJAX is based on internet standards, and uses a combination of: • XMLHttpRequest object (to exchange data asynchronously with a server) • JavaScript/DOM (to display/interact with the information) • CSS (to style the data) • XML (often used as the format for transferring data) AJAX applications are browser and platformindependent! Google Suggest AJAX was made popular in 2005 by Google, with Google Suggest. Google Suggest is using AJAX to create a very dynamic web interface: When you start typing in Google's search box, a JavaScript sends the letters off to a server and the server returns a list of suggestions. Start Using AJAX Today In our PHP tutorial, we will demonstrate how AJAX can update parts of a web page, without reloading the whole page. The server script will be written in PHP. If you want to learn more about AJAX, visit our AJAX tutorial. PHP AJAX and PHP AJAX is used to create more interactive applications.
- 74. AJAX PHP Example The following example will demonstrate how a web page can communicate with a web server while a user type characters in an input field: Example Start typing a name in the input field below: First name: þÿ Suggestions: Example Explained The HTML Page When a user types a character in the input field above, the function "showHint()" is executed. The function is triggered by the "onkeyup" event: <html> <head> <script type="text/javascript"> function showHint(str) { if (str.length==0) { document.getElementById("txtHint").innerHTML=""; return; } var url="gethint.php"; url=url+"?q="+str; url=url+"&sid="+Math.random(); if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp=new XMLHttpRequest(); } else {// code for IE6, IE5 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 && xmlhttp.status==200) { document.getElementById("txtHint").innerHTML=xmlhttp.responseText; } } xmlhttp.open("GET",url,true); xmlhttp.send(); } </script> </head <body> <p><b>Start typing a name in the input field below:</b></p> <form> First name: <input type="text" onkeyup="showHint(this.value)" size="20" /> </form> <p>Suggestions: <span id="txtHint"></span></p>
- 75. </body> </html> Source code explanation: If the input field is empty (str.length==0), the function clears the content of the txtHint placeholder and exits the function. If the input field is not empty, the showHint() function executes the following: • Define the filename (to request from the server) in a variable called url • Add a parameter (q) to the url variable, with the content of the input field • Add a random number to the url variable, to avoid getting a cached file • Create an XMLHttpRequest object • Create the function to be executed when the server response is ready • Send the request off to the server The PHP File The page on the server called by the JavaScript above is a PHP file called "gethint.php". The source code in "gethint.php" checks an array of names, and returns the corresponding name(s) to the browser: <?php // Fill up array with names $a[]="Anna"; $a[]="Brittany"; $a[]="Cinderella"; $a[]="Diana"; $a[]="Eva"; $a[]="Fiona"; $a[]="Gunda"; $a[]="Hege"; $a[]="Inga"; $a[]="Johanna"; $a[]="Kitty"; $a[]="Linda"; $a[]="Nina"; $a[]="Ophelia"; $a[]="Petunia"; $a[]="Amanda"; $a[]="Raquel"; $a[]="Cindy"; $a[]="Doris"; $a[]="Eve"; $a[]="Evita"; $a[]="Sunniva"; $a[]="Tove"; $a[]="Unni"; $a[]="Violet"; $a[]="Liza"; $a[]="Elizabeth"; $a[]="Ellen"; $a[]="Wenche"; $a[]="Vicky"; //get the q parameter from URL $q=$_GET["q"]; //lookup all hints from array if length of q>0 if (strlen($q) > 0) { $hint="";
- 76. for($i=0; $i<count($a); $i++) { if (strtolower($q)==strtolower(substr($a[$i],0,strlen($q)))) { if ($hint=="") { $hint=$a[$i]; } else { $hint=$hint." , ".$a[$i]; } } } } // Set output to "no suggestion" if no hint were found // or to the correct values if ($hint == "") { $response="no suggestion"; } else { $response=$hint; } //output the response echo $response; ?> Explanation: If there is any text sent from the JavaScript (strlen($q) > 0), the following happens: 1. Find a name matching the characters sent from the JavaScript 2. If no match were found, set the response string to "no suggestion" 3. If one or more matching names were found, set the response string to all these names 4. The response is sent to the "txtHint" placeholder PHP AJAX and MySQL AJAX is used for interactive communication with a database. AJAX Database Example The following example will demonstrate how a web page can fetch information from a database with AJAX: Example þÿPeter Griffin Select a person: Person info will be listed here...
- 77. Example Explained The MySQL Database The database table we use in the example above looks like this: id FirstName LastName Age Hometown Job 1 Peter Griffin 41 Quahog Brewery 2 Lois Griffin 40 Newport Piano Teacher 3 Joseph Swanson 39 Quahog Police Officer 4 Glenn Quagmire 41 Quahog Pilot Example Explained The HTML Page When a user selects a user in the dropdown list above, a function called "showUser()" is executed. The function is triggered by the "onchange" event: <html> <head> <script type="text/javascript"> function showUser(str) { var url="getuser.php"; url=url+"?q="+str; url=url+"&sid="+Math.random(); if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp=new XMLHttpRequest(); } else {// code for IE6, IE5 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 && xmlhttp.status==200) { document.getElementById("txtHint").innerHTML=xmlhttp.responseText; } } xmlhttp.open("GET",url,true); xmlhttp.send(); } </script> </head> <body> <form> Select a User: <select name="users" onchange="showUser(this.value)"> <option value="1">Peter Griffin</option> <option value="2">Lois Griffin</option> <option value="3">Glenn Quagmire</option> <option value="4">Joseph Swanson</option> </select> </form> <br /> <div id="txtHint"><b>Person info will be listed here.</b></div> </body> </html> The showUser() function does the following: • Define the filename (to request from the server) in a variable called url
- 78. • Add a parameter (q) to the url variable, with the content of the dropdown list • Add a random number to the url variable, to avoid getting a cached file • Create an XMLHttpRequest object • Create the function to be executed when the server response is ready • Send the request off to the server The PHP File The page on the server called by the JavaScript above is a PHP file called "getuser.php". The source code in "getuser.php" runs a query against a MySQL database, and returns the result in an HTML table: <?php $q=$_GET["q"]; $con = mysql_connect('localhost', 'peter', 'abc123'); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("ajax_demo", $con); $sql="SELECT * FROM user WHERE id = '".$q."'"; $result = mysql_query($sql); echo "<table border='1'> <tr> <th>Firstname</th> <th>Lastname</th> <th>Age</th> <th>Hometown</th> <th>Job</th> </tr>"; while($row = mysql_fetch_array($result)) { echo "<tr>"; echo "<td>" . $row['FirstName'] . "</td>"; echo "<td>" . $row['LastName'] . "</td>"; echo "<td>" . $row['Age'] . "</td>"; echo "<td>" . $row['Hometown'] . "</td>"; echo "<td>" . $row['Job'] . "</td>"; echo "</tr>"; } echo "</table>"; mysql_close($con); ?> Explanation: When the query is sent from the JavaScript to the PHP file, the following happens: 1. PHP opens a connection to a MySQL server 2. The correct person is found 3. An HTML table is created, filled with data, and sent back to the "txtHint" placeholder PHP Example AJAX and XML AJAX can be used for interactive communication with an XML file.
- 79. AJAX XML example The following example will demonstrate how a web page can fetch information from an XML file with AJAX: Example þÿBob Dylan Select a CD: CD info will be listed here... Example explained The HTML page When a user selects a CD in the dropdown list above, a function called "showCD()" is executed. The function is triggered by the "onchange" event: <html> <head> <script type="text/javascript"> function showCD(str) { var url="getcd.php"; url=url+"?q="+str; url=url+"&sid="+Math.random(); if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp=new XMLHttpRequest(); } else {// code for IE6, IE5 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 && xmlhttp.status==200) { document.getElementById("txtHint").innerHTML=xmlhttp.responseText; } } xmlhttp.open("GET",url,true); xmlhttp.send(); } </script> </head> <body> <form> Select a CD: <select name="cds" onchange="showCD(this.value)"> <option value="Bob Dylan">Bob Dylan</option> <option value="Bonnie Tyler">Bonnie Tyler</option> <option value="Dolly Parton">Dolly Parton</option> </select> </form> <div id="txtHint"><b>CD info will be listed here...</b></div> </body>
- 80. </html> The showCD() function does the following: • Define the filename (to request from the server) in a variable called url • Add a parameter (q) to the url variable, with the content of the dropdown list • Add a random number to the url variable, to avoid getting a cached file • Create an XMLHttpRequest object • Create the function to be executed when the server response is ready • Send the request off to the server The PHP File The page on the server called by the JavaScript above is a PHP file called "getcd.php". The PHP script loads an XML document, "cd_catalog.xml", runs a query against the XML file, and returns the result as HTML: <?php $q=$_GET["q"]; $xmlDoc = new DOMDocument(); $xmlDoc>load("cd_catalog.xml"); $x=$xmlDoc>getElementsByTagName('ARTIST'); for ($i=0; $i<=$x>length1; $i++) { //Process only element nodes if ($x>item($i)>nodeType==1) { if ($x>item($i)>childNodes>item(0)>nodeValue == $q) { $y=($x>item($i)>parentNode); } } } $cd=($y>childNodes); for ($i=0;$i<$cd>length;$i++) { //Process only element nodes if ($cd>item($i)>nodeType==1) { echo("<b>" . $cd>item($i)>nodeName . ":</b> "); echo($cd>item($i)>childNodes>item(0)>nodeValue); echo("<br />"); } } ?> When the CD query is sent from the JavaScript to the PHP page, the following happens: 1. PHP creates an XML DOM object 2. Find all <artist> elements that matches the name sent from the JavaScript 3. Output the album information (send to the "txtHint" placeholder) PHP Example AJAX Live Search AJAX can be used for a more userfriendly and interactive search.
- 81. AJAX Live Search In this example we will demonstrate a live search, where you get search results while you type. Live search has many benefits compared to traditional searching: • Results are shown as you type • Results narrow as you continue typing • If results become too narrow, remove characters to see a broader result Search for a W3Schools page in the input field below: þÿ In the example above, the results are found in an XML document (links.xml). To make this example small and simple, only eight results are available. Example Explained The HTML page The HTML page contains a link to an external JavaScript, some style definitions, an HTML form, and a div element: <html> <head> <script type="text/javascript" src="livesearch.js"></script> <style type="text/css"> #livesearch { margin:0px; width:194px; } #txt1 { margin:0px; } </style> </head> <body> <form> <input type="text" id="txt1" size="30" onkeyup="showResult(this.value)" /> <div id="livesearch"></div> </form> </body> </html> The HTML form works like this: 1. An event is triggered when the user presses, and releases a key in the input field 2. When the event is triggered, the function showResult() is executed 3. The <div id="livesearch"> is a placeholder for the data returned from the showResult() function Example Explained The JavaScript code This is the JavaScript code stored in the file "livesearch.js": var xmlhttp; function showResult(str) { if (str.length==0) {
- 82. document.getElementById("livesearch").innerHTML=""; document.getElementById("livesearch").style.border="0px"; return; } xmlhttp=GetXmlHttpObject() if (xmlhttp==null) { alert ("Your browser does not support XML HTTP Request"); return; } var url="livesearch.php"; url=url+"?q="+str; url=url+"&sid="+Math.random(); xmlhttp.onreadystatechange=stateChanged ; xmlhttp.open("GET",url,true); xmlhttp.send(null); } function stateChanged() { if (xmlhttp.readyState==4) { document.getElementById("livesearch").innerHTML=xmlhttp.responseText; document.getElementById("livesearch").style.border="1px solid #A5ACB2"; } } function GetXmlHttpObject() { if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari return new XMLHttpRequest(); } if (window.ActiveXObject) { // code for IE6, IE5 return new ActiveXObject("Microsoft.XMLHTTP"); } return null; } The GetXmlHttpObject() function is the same as in the PHP AJAX Suggest chapter. The showResult() Function This function executes every time a character is entered in the input field. If there is no input in the text field (str.length == 0), the function sets the return field to empty and removes the border around it. However, if there is any input in the text field, the function executes the following: 1. Calls the GetXmlHttpObject() function to create an XMLHTTP object 2. Defines the URL (filename) to send to the server 3. Adds a parameter (q) to the URL with the content of the input field 4. Adds a random number to prevent the server from using a cached file 5. Each time the readyState property changes, the stateChanged() function will be executed 6. Opens the XMLHTTP object with the given URL 7. Sends an HTTP request to the server The stateChanged() Function This function executes every time the state of the XMLHTTP object changes. When the state changes to 4 ("complete"), the content of the txtHint placeholder is filled with the response text, and a border is set around the field. Example Explained The PHP page The PHP page called by the JavaScript code is called "livesearch.php".
- 83. The code searches an XML file for titles matching the search string and returns the result as HTML: <?php $xmlDoc = new DOMDocument(); $xmlDoc>load("links.xml"); $x=$xmlDoc>getElementsByTagName('link'); //get the q parameter from URL $q=$_GET["q"]; //lookup all links from the xml file if length of q>0 if (strlen($q) > 0) { $hint=""; for($i=0; $i<($x>length); $i++) { $y=$x>item($i)>getElementsByTagName('title'); $z=$x>item($i)>getElementsByTagName('url'); if ($y>item(0)>nodeType==1) { //find a link matching the search text if (stristr($y>item(0)>childNodes>item(0)>nodeValue,$q)) { if ($hint=="") { $hint="<a href='" . $z>item(0)>childNodes>item(0)>nodeValue . "' target='_blank'>" . $y>item(0)>childNodes>item(0)>nodeValue . "</a>"; } else { $hint=$hint . "<br /><a href='" . $z>item(0)>childNodes>item(0)>nodeValue . "' target='_blank'>" . $y>item(0)>childNodes>item(0)>nodeValue . "</a>"; } } } } } // Set output to "no suggestion" if no hint were found // or to the correct values if ($hint == "") { $response="no suggestion"; } else { $response=$hint; } //output the response echo $response; ?> If there is any text sent from the JavaScript (strlen($q) > 0), the following happens: 1. PHP creates an XML DOM object of the "links.xml" file 2. Loops through all <title> elements to find titles that match the text sent from the JavaScript 3. Sets the correct link and title in the "$response" variable. If more than one match is found, all matches are added to the variable 4. If no matches are found, the $response variable is set to "no suggestion" 5. Output the $respone variable to the "livesearch" placeholder
- 84. PHP Example AJAX RSS Reader An RSS Reader is used to read RSS Feeds. AJAX RSS Reader In this example we will demonstrate an RSS reader, where the content from the RSS is loaded into a webpage without refreshing. þÿGoogle News Select an RSSfeed: RSSfeed will be listed here... Example Explained The HTML page The HTML page contains a link to an external JavaScript, an HTML form, and a div element: <html> <head> <script type="text/javascript" src="getrss.js"></script> </head> <body> <form> Select an RSSfeed: <select onchange="showRSS(this.value)"> <option value="Google">Google News</option> <option value="MSNBC">MSNBC News</option> </select> </form> <p><div id="rssOutput"> <b>RSSfeed will be listed here...</b></div></p> </body> </html> The HTML form works like this: 1. An event is triggered when a user selects an option in the dropdown box 2. When the event is triggered, the function showRSS() is executed 3. The <div id="rssOutput"> is a placeholder for the data returned from the showRSS() function Example Explained The JavaScript code This is the JavaScript code stored in the file "getrss.js": var xmlhttp; function showRSS(str) { xmlhttp=GetXmlHttpObject(); if (xmlhttp==null) { alert ("Your browser does not support XML HTTP Request"); return; } var url="getrss.php"; url=url+"?q="+str; url=url+"&sid="+Math.random(); xmlhttp.onreadystatechange=stateChanged; xmlhttp.open("GET",url,true);
- 85. xmlhttp.send(null); } function stateChanged() { if (xmlhttp.readyState==4) { document.getElementById("rssOutput").innerHTML=xmlhttp.responseText; } } function GetXmlHttpObject() { if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari return new XMLHttpRequest(); } if (window.ActiveXObject) { // code for IE6, IE5 return new ActiveXObject("Microsoft.XMLHTTP"); } return null; } The stateChanged() and GetXmlHttpObject functions are the same as in the PHP AJAX Suggest chapter. The showRSS() Function Every time an option is selected in the input field, this function executes the following: 1. Calls the GetXmlHttpObject() function to create an XMLHTTP object 2. Defines the URL (filename) to send to the server 3. Adds a parameter (q) to the URL with the selected option from the dropdown list 4. Adds a random number to prevent the server from using a cached file 5. Each time the readyState property changes, the stateChanged() function will be executed 6. Opens the XMLHTTP object with the given URL 7. Sends an HTTP request to the server Example Explained The PHP page The PHP page called by the JavaScript code is called "getrss.php": <?php //get the q parameter from URL $q=$_GET["q"]; //find out which feed was selected if($q=="Google") { $xml=("http://news.google.com/news?ned=us&topic=h&output=rss"); } elseif($q=="MSNBC") { $xml=("http://rss.msnbc.msn.com/id/3032091/device/rss/rss.xml"); } $xmlDoc = new DOMDocument(); $xmlDoc>load($xml); //get elements from "<channel>" $channel=$xmlDoc>getElementsByTagName('channel')>item(0); $channel_title = $channel>getElementsByTagName('title') >item(0)>childNodes>item(0)>nodeValue; $channel_link = $channel>getElementsByTagName('link') >item(0)>childNodes>item(0)>nodeValue;
- 86. $channel_desc = $channel>getElementsByTagName('description') >item(0)>childNodes>item(0)>nodeValue; //output elements from "<channel>" echo("<p><a href='" . $channel_link . "'>" . $channel_title . "</a>"); echo("<br />"); echo($channel_desc . "</p>"); //get and output "<item>" elements $x=$xmlDoc>getElementsByTagName('item'); for ($i=0; $i<=2; $i++) { $item_title=$x>item($i)>getElementsByTagName('title') >item(0)>childNodes>item(0)>nodeValue; $item_link=$x>item($i)>getElementsByTagName('link') >item(0)>childNodes>item(0)>nodeValue; $item_desc=$x>item($i)>getElementsByTagName('description') >item(0)>childNodes>item(0)>nodeValue; echo ("<p><a href='" . $item_link . "'>" . $item_title . "</a>"); echo ("<br />"); echo ($item_desc . "</p>"); } ?> When an option is sent from the JavaScript, the following happens: 1. PHP finds out which RSS feed was selected 2. An XML DOM object is created for the selected RSS feed 3. The elements from the RSS channel are found and outputted 4. Loops through the first three elements and output result PHP Example AJAX Poll AJAX Poll This example will demonstrate a poll where a web page can get results without reloading. Do you like PHP and AJAX so far? Yes: No: Example Explained The HTML page The HTML page contains a link to an external JavaScript, an HTML form, and a div element: <html> <head> <script type="text/javascript" src="poll.js"></script> </head> <body> <div id="poll"> <h3>Do you like PHP and AJAX so far?</h3> <form> Yes: <input type="radio" name="vote" value="0" onclick="getVote(this.value)" /> <br />No: <input type="radio" name="vote" value="1" onclick="getVote(this.value)" /> </form>
- 87. </div> </body> </html> The HTML form works like this: 1. An event is triggered when the user selects the "yes" or "no" option 2. When the event is triggered, the function getVote() is executed 3. The data returned from the getVote() function will replace the form, in the <div> tag Example Explained The JavaScript code This is the JavaScript code stored in the file "poll.js": var xmlhttp; function getVote(int) { xmlhttp=GetXmlHttpObject(); if (xmlhttp==null) { alert ("Browser does not support HTTP Request"); return; } var url="poll_vote.php"; url=url+"?vote="+int; url=url+"&sid="+Math.random(); xmlhttp.onreadystatechange=stateChanged; xmlhttp.open("GET",url,true); xmlhttp.send(null); } function stateChanged() { if (xmlhttp.readyState==4) { document.getElementById("poll").innerHTML=xmlhttp.responseText; } } function GetXmlHttpObject() { var objXMLHttp=null; if (window.XMLHttpRequest) { objXMLHttp=new XMLHttpRequest(); } else if (window.ActiveXObject) { objXMLHttp=new ActiveXObject("Microsoft.XMLHTTP"); } return objXMLHttp; } The stateChanged() and GetXmlHttpObject functions are the same as in the PHP AJAX Suggest chapter. The getVote() Function This function executes when "yes" or "no" is selected in the HTML form. 1. Calls the GetXmlHttpObject() function to create an XMLHTTP object 2. Defines the URL (filename) to send to the server 3. Adds a parameter (vote) to the URL with the content of the input field 4. Adds a random number to prevent the server from using a cached file 5. Each time the readyState property changes, the stateChanged() function will be executed 6. Opens the XMLHTTP object with the given url. 7. Sends an HTTP request to the server
- 88. The PHP Page The server page called by the JavaScript code is a simple PHP file called "poll_vote.php". <?php $vote = $_REQUEST['vote']; //get content of textfile $filename = "poll_result.txt"; $content = file($filename); //put content in array $array = explode("||", $content[0]); $yes = $array[0]; $no = $array[1]; if ($vote == 0) { $yes = $yes + 1; } if ($vote == 1) { $no = $no + 1; } //insert votes to txt file $insertvote = $yes."||".$no; $fp = fopen($filename,"w"); fputs($fp,$insertvote); fclose($fp); ?> <h2>Result:</h2> <table> <tr> <td>Yes:</td> <td> <img src="poll.gif" width='<?php echo(100*round($yes/($no+$yes),2)); ?>' height='20'> <?php echo(100*round($yes/($no+$yes),2)); ?>% </td> </tr> <tr> <td>No:</td> <td> <img src="poll.gif" width='<?php echo(100*round($no/($no+$yes),2)); ?>' height='20'> <?php echo(100*round($no/($no+$yes),2)); ?>% </td> </tr> </table> The selected value is sent from the JavaScript and the following happens: 1. Get the content of the "poll_result.txt" file 2. Put the content of the file in variables and add one to the selected variable 3. Write the result to the "poll_result.txt" file 4. Output a graphical representation of the poll result
- 89.