Jinja (template engine)

Jinja is a template engine for the Python programming language and is licensed under a BSD License created by Armin Ronacher. It 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 sourcecode.

The Jinja template engine allows customization of tags,^[1] filters, tests, and globals.^[2] 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.^[3]

Features

Some of the features of Jinja are:^[4]

sandboxed execution
powerful 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. 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'^[5]

<!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

^ "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.
^ http://jinja.pocoo.org/docs/dev/3 ^{[dead link]}
^ 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

[Jinja2_Documentation_(2.8-dev)-1] "Extensions". Jinja2 Documentation (2.8-dev). Retrieved 2015-05-26.

[Jinja2_Documentation_(2.8-dev)_2-2] "Extensions". Jinja2 Documentation (2.8-dev). Retrieved 2015-05-26.

[DuPlain_2013_p._30-3] DuPlain, R. (2013). Instant Flask Web Development. Packt Publishing. p. 30. ISBN 978-1-78216-963-5. Retrieved 2015-05-26.

[4] ttp://jinja.pocoo.org/docs/dev/3 ^{[dead link]}

[5] 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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