This is a pre-production deployment of Warehouse, however changes made here WILL affect the production instance of PyPI.
Latest Version Dependencies status unknown Test status unknown Test coverage unknown
Project Description
__What it is:__

A lightweight package for django which does the filtering of django querysets. The central object - a filter - is a callable that takes a queryset as a parameter and returns a queryset:

filtered_queryset = filtr(Model.objects.all())

Django itself has a similar object - Q-object (`django.db.models.Q`). Q-objects can be combined toghether (with `|`, `&` operations) or inverted (`~`) and then passed to `queryset.filter`.

With `qfilters`, what you get in the most common case, is just a wrapper around the Q-object. However there are __2 features__ that may be the reasons to use the package:

__1. Support for additional filter types.__

For example, there is `ValuesDictFilter`, that is constructed from a field list, that will be passed to `queryset.values` and retrieve a list of dictionaries, and a filtering function, which accepts that dict as a parameter.

This filters can be combined or inverted in the same way Q-objects do, so that using multiple filters would result in a single call to `queryset.values`.

This is what it looks like in practice (all examples are taken from the `qfilter` testsuite):

@ValuesDictFilter('@', fields_list=['traits__good_hunter'])
def nas_i_zdes_neploho_kormyat(obj):
return obj['traits__good_hunter'] is False # because it can be None

cats = nas_i_zdes_neploho_kormyat(self.CatsBreed.objects.all())
assert cats.exists()

There are also exotic variants (`qfilters.exotic_types`) like `QuerysetIterationHook`, which appends attributes to objects when queryset is iterated over. Another one is `PropertyBasedFilter`, which can access object's attributes and even properties like it were a regular django model object. The implementation is not very straightforward, still it passes the tests so far. Here is what it looks like:

class CatsBreed(models.Model):
# ...
traits = models.OneToOneField('Traits')

class Traits(models.Model):
#...
weight_min = models.FloatField(u'Вес от, кг', null=True)
weight_max = models.FloatField(u'Вес до, кг', null=True)
# if you can't specify min and max
weight = models.FloatField(u'Вес, кг', null=True)

@property
def kg(self):
return self.weight or self.weight_max


from qfilters import PropertyBasedFilter

@PropertyBasedFilter('@',
fields_list=['traits__weight', 'traits__weight_max'],
properties=['traits.kg'])
def light_cats(obj):
return not obj.traits.kg or obj.traits.kg < 3

assert light_cats(CatsBreed.objects.all()).exists()

__2. Using class as container: methods are filters__

It is convenient to have an object, which can hold some context (for example, the view itself),
and let the methods be filters, and be able to access this context. `qfilters.containers` provide this functionality, specifically, there is a `MethodFilter` class:

from qfilter import MethodFilter

class ManyFilters(MethodFilter):

def filter__q(self):
return Q(name__in=[u'Сиамская', u'Норвежская лесная'])

@make_filter(PropertyBasedFilter,
fields_list=['traits__weight', 'traits__weight_max'],
properties=['traits.kg'])
def filter__big(self, cat):
return cat.traits.kg and cat.traits.kg > 5

def filter__q_yet_another(self):
return Q(name__in=[u'Персидская', u'Норвежская лесная'])

filters = ManyFilters()
cat = filters(CatsBreed.objects.all())[0]

The idea was born from the experience of using the [django-rest-framework](http://www.django-rest-framework.org/) There is a notion of filter backend (a class) which every view knows about. First I implemented a simple method-based filter backend, the possible return values for the methods were eiher a Q-object or a queryset. But then I got difficulties with debugging since the return value doesn't even know which method it came from. Thus, I decided it will be a good idea to have this filter obbject.

P.S. `qfilters` does not provide a filter backend to use with django-rest-framework, but it's a piece of cake to write one.
Release History

Release History

0.1

This version

History Node

TODO: Figure out how to actually get changelog content.

Changelog content for this version goes here.

Donec et mollis dolor. Praesent et diam eget libero egestas mattis sit amet vitae augue. Nam tincidunt congue enim, ut porta lorem lacinia consectetur. Donec ut libero sed arcu vehicula ultricies a non tortor. Lorem ipsum dolor sit amet, consectetur adipiscing elit.

Show More

Download Files

Download Files

TODO: Brief introduction on what you do with files - including link to relevant help section.

File Name & Checksum SHA256 Checksum Help Version File Type Upload Date
qfilters-0.1-py2.py3-none-any.whl (10.8 kB) Copy SHA256 Checksum SHA256 py2.py3 Wheel May 18, 2014
qfilters-0.1.tar.gz (7.0 kB) Copy SHA256 Checksum SHA256 Source May 18, 2014

Supported By

WebFaction WebFaction Technical Writing Elastic Elastic Search Pingdom Pingdom Monitoring Dyn Dyn DNS HPE HPE Development Sentry Sentry Error Logging CloudAMQP CloudAMQP RabbitMQ Heroku Heroku PaaS Kabu Creative Kabu Creative UX & Design Fastly Fastly CDN DigiCert DigiCert EV Certificate Rackspace Rackspace Cloud Servers DreamHost DreamHost Log Hosting