djangorestframework-filters 0.9.0

Django Rest Framework Filters
=============================

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``django-rest-framework-filters`` is an extension to `Django REST framework`_ and `Django filter`_
that makes it easy to filter across relationships. Historically, this extension also provided a
number of additional features and fixes, however the number of features has shrunk as they are
merged back into ``django-filter``.

.. _`Django REST framework`: https://github.com/tomchristie/django-rest-framework
.. _`Django filter`: https://github.com/carltongibson/django-filter

Using ``django-rest-framework-filters``, we can easily do stuff like::

/api/article?author__first_name__icontains=john
/api/article?is_published!=true


Features
--------

* Easy filtering across relationships
* Support for method filtering across relationships
* Automatic filter negation with a simple ``param!=value`` syntax
* Backend caching to increase performance


Requirements
------------

* Python 2.7 or 3.3+
* Django 1.8, 1.9, 1.10
* Django REST framework 3.3, 3.4


Installation
------------

.. code-block:: bash

$ pip install djangorestframework-filters


Usage
-----

Upgrading from ``django-filter`` to ``django-rest-framework-filters`` is straightforward:

* Import from ``rest_framework_filters`` instead of from ``django_filters``
* Use the ``rest_framework_filters`` backend instead of the one provided by ``django_filter``.

.. code-block:: python

# django-filter
from django_filters.rest_framework import FilterSet, filters

class ProductFilter(FilterSet):
manufacturer = filters.ModelChoiceFilter(queryset=Manufacturer.objects.all())
...


# django-rest-framework-filters
import rest_framework_filters as filters

class ProductFilter(filters.FilterSet):
manufacturer = filters.ModelChoiceFilter(queryset=Manufacturer.objects.all())
...


To use the django-rest-framework-filters backend, add the following to your settings:

.. code-block:: python

REST_FRAMEWORK = {
'DEFAULT_FILTER_BACKENDS': (
'rest_framework_filters.backends.DjangoFilterBackend', ...
),
...


Once configured, you can continue to use all of the filters found in ``django-filter``.


Filtering across relationships
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can easily traverse multiple relationships when filtering by using ``RelatedFilter``:

.. code-block:: python

from rest_framework import viewsets
import rest_framework_filters as filters


class ManagerFilter(filters.FilterSet):
class Meta:
model = Manager
fields = {'name': ['exact', 'in', 'startswith']}


class DepartmentFilter(filters.FilterSet):
manager = filters.RelatedFilter(ManagerFilter, name='manager')

class Meta:
model = Department
fields = {'name': ['exact', 'in', 'startswith']}


class CompanyFilter(filters.FilterSet):
department = filters.RelatedFilter(DepartmentFilter, name='department')

class Meta:
model = Company
fields = {'name': ['exact', 'in', 'startswith']}


# company viewset
class CompanyView(viewsets.ModelViewSet):
filter_class = CompanyFilter
...

Example filter calls:

.. code-block:: http

/api/companies?department__name=Accounting
/api/companies?department__manager__name__startswith=Bob

Recursive relations are also supported. It may be necessary to specify the full module path.

.. code-block:: python

class PersonFilter(filters.FilterSet):
name = filters.AllLookupsFilter(name='name')
best_friend = filters.RelatedFilter('people.views.PersonFilter', name='best_friend')

class Meta:
model = Person

Supporting ``Filter.method``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

``django_filters.MethodFilter`` has been deprecated and reimplemented as the ``method`` argument
to all filter classes. It incorporates some of the implementation details of the old
``rest_framework_filters.MethodFilter``, but requires less boilerplate and is simpler to write.

* It is no longer necessary to perform empty/null value checking.
* You may use any filter class (``CharFilter``, ``BooleanFilter``, etc...) which will
validate input values for you.
* The argument signature has changed from ``(name, qs, value)`` to ``(qs, name, value)``.

.. code-block:: python

class PostFilter(filters.FilterSet):
# Note the use of BooleanFilter, the original model field's name, and the method argument.
is_published = filters.BooleanFilter(name='date_published', method='filter_is_published')

class Meta:
model = Post
fields = ['title', 'content']

def filter_is_published(self, qs, name, value):
"""
`is_published` is based on the `date_published` model field.
If the publishing date is null, then the post is not published.
"""
# incoming value is normalized as a boolean by BooleanFilter
isnull = not value
lookup_expr = LOOKUP_SEP.join([name, 'isnull'])

return qs.filter(**{lookup_expr: isnull})

class AuthorFilter(filters.FilterSet):
posts = filters.RelatedFilter('PostFilter')

class Meta:
model = Author
fields = ['name']

The above would enable the following filter calls:

.. code-block:: http

/api/posts?is_published=true
/api/authors?posts__is_published=true


In the first API call, the filter method receives a queryset of posts. In the second,
it receives a queryset of users. The filter method in the example modifies the lookup
name to work across the relationship, allowing you to find published posts, or authors
who have published posts.

Automatic Filter Negation/Exclusion
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

FilterSets support automatic exclusion using a simple ``param!=value`` syntax. This syntax
internally sets the ``exclude`` property on the filter.

.. code-block:: http

/api/page?title!=The%20Park

This syntax supports regular filtering combined with exclusion filtering. For example, the
following would search for all articles containing "Hello" in the title, while excluding
those containing "World".

.. code-block:: http

/api/articles?title__contains=Hello&title__contains!=World

Note that most filters only accept a single query parameter. In the above, ``title__contains``
and ``title__contains!`` are interpreted as two separate query parameters. The following would
probably be invalid, although it depends on the specifics of the individual filter class:

.. code-block:: http

/api/articles?title__contains=Hello&title__contains!=World&title_contains!=Friend


Allowing any lookup type on a field
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you need to enable several lookups for a field, django-filter provides the dict-syntax for
``Meta.fields``.

.. code-block:: python

class ProductFilter(filters.FilterSet):
class Meta:
model = Product
fields = {
'price': ['exact', 'lt', 'gt', ...],
}

``django-rest-framework-filters`` also allows you to enable all possible lookups for any field.
This can be achieved through the use of ``AllLookupsFilter`` or using the ``'__all__'`` value in
the ``Meta.fields`` dict-style syntax. Generated filters (``Meta.fields``, ``AllLookupsFilter``)
will never override your declared filters.

Note that using all lookups comes with the same admonitions as enabling ``'__all__'`` fields in
django forms (`docs`_). Exposing all lookups may allow users to construct queries that
inadvertently leak data. Use this feature responsibly.

.. _`docs`: https://docs.djangoproject.com/en/1.10/topics/forms/modelforms/#selecting-the-fields-to-use

.. code-block:: python

class ProductFilter(filters.FilterSet):
# Not overridden by `__all__`
price__gt = filters.NumberFilter(name='price', lookup_expr='gt', label='Minimum price')

class Meta:
model = Product
fields = {
'price': '__all__',
}

# or

class ProductFilter(filters.FilterSet):
price = filters.AllLookupsFilter()

# Not overridden by `AllLookupsFilter`
price__gt = filters.NumberFilter(name='price', lookup_expr='gt', label='Minimum price')

class Meta:
model = Product

You cannot combine ``AllLookupsFilter`` with ``RelatedFilter`` as the filter names would clash.

.. code-block:: python

class ProductFilter(filters.FilterSet):
manufacturer = filters.RelatedFilter('ManufacturerFilter')
manufacturer = filters.AllLookupsFilter()

To work around this, you have the following options:

.. code-block:: python

class ProductFilter(filters.FilterSet):
manufacturer = filters.RelatedFilter('ManufacturerFilter')

class Meta:
model = Product
fields = {
'manufacturer': '__all__',
}

# or

class ProductFilter(filters.FilterSet):
manufacturer = filters.RelatedFilter('ManufacturerFilter', lookups='__all__') # `lookups` also accepts a list

class Meta:
model = Product


Can I mix and match `django-filter` and `django-rest-framework-filters`?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Yes you can. ``django-rest-framework-filters`` is simply an extension of ``django-filter``. Note
that ``RelatedFilter`` and other ``django-rest-framework-filters`` features are designed to work
with ``rest_framework_filters.FilterSet`` and will not function on a ``django_filters.FilterSet``.
However, the target ``RelatedFilter.filterset`` may point to a ``FilterSet`` from either package
and ``FilterSet``s from either package are compatible with the other's DRF backend.

.. code-block:: python

# valid
class VanillaFilter(django_filters.FilterSet):
...

class DRFFilter(rest_framework_filters.FilterSet):
vanilla = rest_framework_filters.RelatedFilter(filterset=VanillaFilter)


# invalid
class DRFFilter(rest_framework_filters.FilterSet):
...

class VanillaFilter(django_filters.FilterSet):
drf = rest_framework_filters.RelatedFilter(filterset=DRFFilter)


License
-------
Copyright (c) 2013-2015 Philip Neustrom <philipn@gmail.com>,
2016 Ryan P Kilby <rpkilby@ncsu.edu>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.