flask/docs/extensions.rst

Flask Extensions
================

Flask extensions extend the functionality of Flask in various different
ways.  For instance they add support for databases and other common tasks.

Finding Extensions
------------------

Flask extensions are listed on the `Flask Extension Registry`_ and can be
downloaded with ``easy_install`` or ``pip``.  If you add a Flask extension
as dependency to your ``requirements.rst`` or ``setup.py`` file they are
usually installed with a simple command or when your application installs.

Using Extensions
----------------

Extensions typically have documentation that goes along that shows how to
use it.  There are no general rules in how extensions are supposed to
behave but they are imported from common locations.  If you have an
extension called ``Flask-Foo`` or ``Foo-Flask`` it will be always
importable from ``flask.ext.foo``::

    from flask.ext import foo

Flask < 0.8
-----------

If you are using Flask 0.7 or earlier the :data:`flask.ext` package will not
exist, instead you have to import from ``flaskext.foo`` or ``flask_foo``
depending on how the extension is distributed.

We recommend importing from ``flask.ext`` even with older versions of
Flask however.  If you have an application that needs to work with
versions of Flask older than 0.8 you should activate the
``flaskext_compat`` module which provides the ``flask.ext`` module if
you activate it.  You can download it from github: `flaskext_compat.py`_

And here is how you can use it::

    import flaskext_compat
    flaskext_compat.activate()

    from flask.ext import foo

Once the ``flaskext_compat`` module is activated the :data:`flask.ext` will
exist and you can start importing from there.

.. _Flask Extension Registry: http://flask.pocoo.org/extensions/
.. _flaskext_compat.py: https://github.com/mitsuhiko/flask/raw/master/scripts/flaskext_compat.py