Jinja (template engine)

Jinja
Original author(s)	Armin Ronacher
Initial release	July 17, 2008; 16 years ago
Stable release	2.11.2 / April 13, 2020; 4 years ago
Repository	github.com/pallets/jinja ;
Written in	Python
Type	Template engine
License	BSD License
Website	palletsprojects.com/p/jinja/

Jinja is a web template engine for the Python programming language. It was created by Armin Ronacher and is licensed under a BSD License. Jinja is similar to the Django template engine but provides Python-like expressions while ensuring that the templates are evaluated in a sandbox. It is a text-based template language and thus can be used to generate any markup as well as source code.

The Jinja template engine allows customization of tags,^[2] filters, tests, and globals.^[3] Also, unlike the Django template engine, Jinja allows the template designer to call functions with arguments on objects. Jinja is Flask's default template engine ^[4] and it is also used by Ansible ^[5] and Trac.

Features

Some of the features of Jinja are:^[6]

sandboxed execution
automatic HTML escaping to prevent cross-site scripting (XSS) attacks
template inheritance
compiles down to the optimal Python code just-in-time
optional ahead-of-time template compilation
easy to debug (for example, line numbers of exceptions directly point to the correct line in the template)
configurable syntax

Jinja, like Smarty, also ships with an easy-to-use filter system similar to the Unix pipeline.

Example

Here is a small example of a template file example.html.jinja:^[7]

<!DOCTYPE html>
<html>
  <head>
    <title>{{ variable|escape }}</title>
  </head>
  <body>
  {%- for item in item_list %}
    {{ item }}{% if not loop.last %},{% endif %}
  {%- endfor %}
  </body>
</html>

and templating code:

from jinja2 import Template
with open('example.html.jinja') as f:
    tmpl = Template(f.read())
print(tmpl.render(
    variable = 'Value with <unsafe> data',
    item_list = [1, 2, 3, 4, 5, 6]
))

This produces the HTML string:

<!DOCTYPE html>
<html>
  <head>
    <title>Value with &lt;unsafe&gt; data</title>
  </head>
  <body>
    1,
    2,
    3,
    4,
    5,
    6
  </body>
</html>

Sources

^ ^a ^b "Jinja2 Release History". Retrieved 24 June 2020.
^ "Extensions". Jinja2 Documentation (2.8-dev). Retrieved 2015-05-26.
^ "Extensions". Jinja2 Documentation (2.8-dev). Retrieved 2015-05-26.
^ DuPlain, R. (2013). Instant Flask Web Development. Packt Publishing. p. 30. ISBN 978-1-78216-963-5. Retrieved 2015-05-26.
^ https://docs.ansible.com/ansible/latest/user_guide/playbooks_templating.html
^ "Welcome | Jinja2 (The Python Template Engine)". palletsprojects.com/p/jinja.
^ Ronacher, Armin. "Template Designer Documentation". Jinja2 Documentation. Retrieved 7 January 2016. A Jinja template doesn't need to have a specific extension: .html, .xml, or any other extension is just fine.

External links

Jinja website
Jinja2 on Python pypi
jinja2 on GitHub

[history-1] "Jinja2 Release History". Retrieved 24 June 2020.

[Jinja2_Documentation_(2.8-dev)-2] "Extensions". Jinja2 Documentation (2.8-dev). Retrieved 2015-05-26.

[Jinja2_Documentation_(2.8-dev)_2-3] "Extensions". Jinja2 Documentation (2.8-dev). Retrieved 2015-05-26.

[DuPlain_2013_p._30-4] DuPlain, R. (2013). Instant Flask Web Development. Packt Publishing. p. 30. ISBN 978-1-78216-963-5. Retrieved 2015-05-26.

[5] ttps://docs.ansible.com/ansible/latest/user_guide/playbooks_templating.html

[6] "Welcome | Jinja2 (The Python Template Engine)". palletsprojects.com/p/jinja.

[7] Ronacher, Armin. "Template Designer Documentation". Jinja2 Documentation. Retrieved 7 January 2016. A Jinja template doesn't need to have a specific extension: .html, .xml, or any other extension is just fine.

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