Jinja (template engine)

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Jinja is a template engine for the Python programming language and is licensed under a BSD License. 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[edit]

Some of the features of Jinja are:[4]

  • sandboxed execution
  • powerful automatic HTML escaping system for XSS prevention
  • 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[edit]

Here is a small example of a template:

from jinja2 import Template

tmpl = Template(u'''\
<!DOCTYPE html>
<html>
  <head>
    <title>{{ variable|escape }}</title>
  </head>
  <body>
  {%- for item in item_list %}
    {{ item }}{% if not loop.last %},{% endif %}
  {%- endfor %}
  </body>
</html>
''')

print tmpl.render(
    variable = 'Value with <unsafe> data',
    item_list = [1, 2, 3, 4, 5, 6]
)

This produces the HTML:

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

Sources[edit]

  1. ^ "Extensions". Jinja2 Documentation (2.8-dev). Retrieved 2015-05-26. 
  2. ^ "Extensions". Jinja2 Documentation (2.8-dev). Retrieved 2015-05-26. 
  3. ^ DuPlain, R. (2013). Instant Flask Web Development. Packt Publishing. p. 30. ISBN 978-1-78216-963-5. Retrieved 2015-05-26. 
  4. ^ http://jinja.pocoo.org/docs/dev/3[dead link]

External links[edit]