# Django 3.2.11.dev documentazione

# Outputting PDFs with Django

This document explains how to output PDF files dynamically using Django views. This is made possible by the excellent, open-source ReportLab Python PDF library.

The advantage of generating PDF files dynamically is that you can create customized PDFs for different purposes – say, for different users or different pieces of content.

For example, Django was used at kusports.com to generate customized, printer-friendly NCAA tournament brackets, as PDF files, for people participating in a March Madness contest.

## Install ReportLab

The ReportLab library is available on PyPI. A user guide (not coincidentally, a PDF file) is also available for download. You can install ReportLab with `pip`:

/ 

    $ python -m pip install reportlab

    ...\> py -m pip install reportlab

Test your installation by importing it in the Python interactive interpreter:

    >>> import reportlab

If that command doesn’t raise any errors, the installation worked.

## Write your view

The key to generating PDFs dynamically with Django is that the ReportLab API acts on file-like objects, and Django’s `FileResponse` objects accept file-like objects.

Here’s a «Hello World» example:

    import io
    from django.http import FileResponse
    from reportlab.pdfgen import canvas

    def some_view(request):
        # Create a file-like buffer to receive PDF data.
        buffer = io.BytesIO()

        # Create the PDF object, using the buffer as its "file."
        p = canvas.Canvas(buffer)

        # Draw things on the PDF. Here's where the PDF generation happens.
        # See the ReportLab documentation for the full list of functionality.
        p.drawString(100, 100, "Hello world.")

        # Close the PDF object cleanly, and we're done.
        p.showPage()
        p.save()

        # FileResponse sets the Content-Disposition header so that browsers
        # present the option to save the file.
        buffer.seek(0)
        return FileResponse(buffer, as_attachment=True, filename='hello.pdf')

The code and comments should be self-explanatory, but a few things deserve a mention:

- The response will automatically set the MIME type application/pdf based on the filename extension. This tells browsers that the document is a PDF file, rather than an HTML file or a generic application/octet-stream binary content.
- When `as_attachment=True` is passed to `FileResponse`, it sets the appropriate `Content-Disposition` header and that tells Web browsers to pop-up a dialog box prompting/confirming how to handle the document even if a default is set on the machine. If the `as_attachment` parameter is omitted, browsers will handle the PDF using whatever program/plugin they’ve been configured to use for PDFs.
- You can provide an arbitrary `filename` parameter. It’ll be used by browsers in the «Save as…» dialog.
- You can hook into the ReportLab API: The same buffer passed as the first argument to `canvas.Canvas` can be fed to the `FileResponse` class.
- Note that all subsequent PDF-generation methods are called on the PDF object (in this case, `p`) – not on `buffer`.
- Finally, it’s important to call `showPage()` and `save()` on the PDF file.

Nota

ReportLab is not thread-safe. Some of our users have reported odd issues with building PDF-generating Django views that are accessed by many people at the same time.

## Other formats

Notice that there isn’t a lot in these examples that’s PDF-specific – just the bits using `reportlab`. You can use a similar technique to generate any arbitrary format that you can find a Python library for. Also see Outputting CSV with Django for another example and some techniques you can use when generated text-based formats.

Vedi anche

Django Packages provides a comparison of packages that help generate PDF files from Django.