[1.3.X] Fixed #16079: Clarified (for real this time) how handler404 and...

Write a 404 (page not found) view

=================================

When you raise :exc:`~django.http.Http404` from within a view, Django will load

a special view devoted to handling 404 errors. It finds it by looking for the

variable ``handler404``, which is a string in Python dotted syntax -- the same

format the normal URLconf callbacks use. A 404 view itself has nothing special:

It's just a normal view.

When you raise :exc:`~django.http.Http404` from within a view, Django

will load a special view devoted to handling 404 errors. It finds it

by looking for the variable ``handler404`` in your root URLconf (and

only in your root URLconf; setting ``handler404`` anywhere else will

have no effect), which is a string in Python dotted syntax -- the same

format the normal URLconf callbacks use. A 404 view itself has nothing

special: It's just a normal view.

You normally won't have to bother with writing 404 views. By default, URLconfs

have the following line up top::

Write a 500 (server error) view

===============================

Similarly, URLconfs may define a ``handler500``, which points to a view to call

in case of server errors. Server errors happen when you have runtime errors in

view code.

Similarly, your root URLconf may define a ``handler500``, which points

to a view to call in case of server errors. Server errors happen when

you have runtime errors in view code.

Use the template system

=======================

       :class:`~django.http.HttpRequest` as its first argument and any values

       captured in the regex as remaining arguments.

    5. If no regex matches, or if an exception is raised during any

       point in this process, Django invokes an appropriate

       error-handling view. See `Error handling`_ below.

Example

=======

``patterns()`` and is only relevant when you're passing a string as the

``view`` parameter.

include

-------

.. function:: include(<module or pattern_list>)

A function that takes a full Python import path to another URLconf module that

should be "included" in this place.

:func:`include` also accepts as an argument an iterable that returns URL

patterns.

See `Including other URLconfs`_ below.

Error handling

==============

When Django can't find a regex matching the requested URL, or when an

exception is raised, Django will invoke an error-handling view. The

views to use for these cases are specified by two variables which can

be set in your root URLconf. Setting these variables in any other

URLconf will have no effect.

See the documentation on :ref:`customizing error views

<customizing-error-views>` for more details.

handler404

----------

.. versionchanged:: 1.2

    Previous versions of Django only accepted strings representing import paths.

include

-------

.. function:: include(<module or pattern_list>)

A function that takes a full Python import path to another URLconf module that

should be "included" in this place.

:func:`include` also accepts as an argument an iterable that returns URL

patterns.

See `Including other URLconfs`_ below.

Notes on capturing text in URLs

===============================

template that is displayed when a 404 error is raised. This template should be

called ``404.html`` and located in the top level of your template tree.

.. _customizing-error-views:

Customizing error views

=======================