Representational State Transfer (REST)

Representational State Transfer (REST)

• 1.
  REST representational state transfer DavidKrmpotić
• 2.
  WHAT IS IT?
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  Architectural style thatbuilds on the existing protocols of the web. Roy Fielding
• 4.
  http://app.com/pics/show/1 http://app.com/pics/destroy/1 RESTful style knocks theverbs out of the urls
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  http://app.com/pics/1 What remains: a (unique)resource identifier an “abstract thing” that lives in the cloud a.k.a. ”the intended conceptual target of a hypertext reference” :] a representation of the resource (you can never access the resource itself, only various representations of it)
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  http:// GET app.com/pics/1 Wehave nouns (resources), but what happened to the verbs? http:// DELETE app.com/pics/1  they moved from the URL to the HTTP request method !
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  IS THIS A GOODTHING?
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  simplicity and abstraction GET PUT POST DELETE Yes! }uniform interface
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  REST is aboutresources Nouns URIs (unconstrained) Verbs GET, PUT, POST, DELETE (constrained) Content Types HTML, JPEG, XML etc. (constrained)
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  GET /pics/1 Accept: JPEG orGET /pics/1.jpg Requesting different resource representations GET /pics/1 Accept: XML or GET /pics/1.xml <picture> <place>Axe Lake</place> <size>1024x768</size> <date>2008-05-01</date> </picture>
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  GET /people Accept: XML Pluralresources GET /people/1 Accept: JPEG <people> <person> <id>1</id> <name>Ann</name> <age>28</age> </person> <person> <id>2</id> <name>Bruce</name> <age>32</age> </person> ... </people>
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  It relies onthe following standards though: HTTP URL XML/HTML/GIF/JPEG/etc (resource representations) text/xml, text/html, image/gif, image/jpeg, etc. (content types) remember REST is not a standard!
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  REST in
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  Before enlightenment http://app.com/clients/show/1 After controller action http://app.com/clients/1 +HTTP method controllermap.resources action
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  map.resources action where therequest lands is shown with gray background edit and new are helper actions for showing the form
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  We also geta few named routes: clients_path new_client_path edit_client_path(id) client_path(id)
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  Custom actions GET /tasks/completedPUT /tasks/12/complete you should add custom actions carefully and never more than two or three
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  Responder block takes careof different resource representations
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  Nested resources (inRails 2) http://adam.blog.heroku.com/past/2007/12/20/nested_resources_in_rails_2/ /events/1/tickets
• 21.
  A resource isnot always a one-to-one mapping to a Rails model or database table. Sometimes a resource is "virtual" and exists in your domain vocabulary and application logic, but is not backed by a database table. [2] GOOD TO KNOW models != resources
• 22.
  To create awebsite that is: • easy to use • easy to maintain • easy to cache • easy to scale Why use REST?
• 23.
  Thank you! Resources (n.p.i.) [1]Roy Fielding’s dissertation (2000) www.ics.uci.edu/~fielding/pubs/dissertation/top.htm [2] REST 101 www.softiesonrails.com/search?q=rest+101 [3] A Brief Introduction to REST www.infoq.com/articles/rest-introduction [4] How I Explained REST to My Wife tomayko.com/writings/rest-to-my-wife