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Generating PDF from Flask template (using xhtml2pdf)

Posted by Marc de Verdelhan on 2011-09-07 @ 06:41 and filed in Template Tricks

Please note:

There are many ways for generating PDF in python. This snippet aims at presenting one of the simplest: with xhtml2pdf.

xhtml2pdf is a fork from an earlier project (called "pisa"). The project packaging is a bit confusing and it's not very well documented, but it allows you to generate nice PDFs, simply, without having to learn all the ReportLab doc. The small documentation (inherited from pisa) can be found here.

How to generate a PDF file from a Flask template using xhtml2pdf

First, create a simple Jinja template at your/template.html. For instance it may contain:

    {% block body %}
        <h2>Some page title.</h2>
        <table width="100%" cellpadding="4" cellspacing="0">
                    <td width="100%">Some text.</td>
                <tr style="border: 1px solid #000000;">
                    <td width="100%">
                        <h3 style="text-align: center;">Some subtitle</h3>
                        <div>{{ g.user.get('user_attribute') }}</div>
        <hr style="margin: 3em 0;"/>
        <img src="{{ url_for('static', filename='img.png', _external=True) }}" />
    {% endblock %}

xhtml2pdf also works with a separate CSS file. All the CSS and (X)HTML tags supported are listed in the documentation.

Then create a pdfs.py file containing:

from xhtml2pdf import pisa
from cStringIO import StringIO

def create_pdf(pdf_data):
    pdf = StringIO()
    pisa.CreatePDF(StringIO(pdf_data.encode('utf-8')), pdf)
    return pdf

Note that you should use Celery on the create_pdf function (adding the @task decorator), because the generation process may be a long operation.

Now you can call create_pdf to create the PDF file from your Flask template (for instance, for an email attachement):

from flask import Flask, render_template, redirect, url_for
from flaskext.mail import Mail, Message
from pdfs import create_pdf
# ...

app = Flask(__name__)
mail_ext = Mail(app)
# ...

def your_view():
    subject = "Mail with PDF"
    receiver = "receiver@mail.com"
    mail_to_be_sent = Message(subject=subject, recipients=[receiver])
    mail_to_be_sent.body = "This email contains PDF."
    pdf = create_pdf(render_template('your/template.html'))
    mail_to_be_sent.attach("file.pdf", "application/pdf", pdf.getvalue())
    return redirect(url_for('other_view'))

Note that email sending should also be "celeryed" (see this thread for more information). ;)

This snippet by Marc de Verdelhan can be used freely for anything you like. Consider it public domain.