Filtering QuerySet based on captured URL parameters in Django?

Question

I'm making a generic template that will be displaying a list of objects from a queryset:

{% for o in objects %}
    {{ o.name }}
{% endfor %}

I want to be able to use the template in multiple situations, where different sorts of filtering and ordering need to be done. I have created a view function for this:

def display_objects(request, filters, orders, template_name):
    objects = Object.objects.all()
    for filter in filters:
        objects = objects.filter(('%s__%s' % (filter['field'], filter['relationship']), filter['value']))
    for order in orders:
        objects = objects.order_by('-' if 'descending' in order else '' + order['field'])
    # render objects to template with context
    pass

I'm not sure if what I have done so far will even work, but I've run into an issue. I don't know if it's feasible to filter the query set by a parameter captured in the URL with my current function.

For example, if I wanted to display objects pertaining to a certain user I would do something like:

(r'^user/(?P<account_username>[^/]+)/$', display_objects, dict(filters=[{'field':'account__username','relationship':'iexact','value':account_username}], orders=[{'field':'foobar'}], template_name='user.html'))

Obviously, account_username isn't a defined field until the URL is parsed and dispatched to the display_objects function. It would be easy enough to make a view function that takes an account_username parameter, but I want to be able to use the function for displaying other object query sets that will be filtered with different captured parameters.

Is there some way I can pass captured URL parameters to a view function to dynamically filter or order a query set to be displayed?

Jordan Reiter · Accepted Answer · 2012-04-09 22:46:14Z

1

Here's one way you can do this:

in urls.py:

(r'^user/(?P<account_username>[^/]+)/$', display_objects, dict(filters=[{'field':'account__username','relationship':'iexact'}], orders=[{'field':'foobar'}], template_name='user.html'))

And then in views.py:

def display_objects(request, filters, orders, template_name, **kwargs):

    objects = Object.objects.all()
    for filter in filters:
        objects = objects.filter(('%s__%s' % (filter['field'], filter['relationship']), kwargs.get(filter['field'])))
    for order in orders:
        objects = objects.order_by('-' if 'descending' in order else '' + order['field'])
    # render objects to template with context
    pass

Although honestly I'm not sure if this is a good way of doing things...

answered Apr 9, 2012 at 22:46

Jordan Reiter

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mburke13 Over a year ago

As I thought about it, I realized that the way that I had structured the view function was probably not optimal. Do you have any suggestions for how else you would dynamically filter and order querysets for templates?

Daniel Roseman · Accepted Answer · 2012-04-09 23:04:39Z

0

You can't pass a string directly to the filter method. You need to translate it into kwargs.

query_string = '%s__%s' % (filter['field'], filter['relationship'])
objects = objects.filter(**{query_string: filter['value']}))

answered Apr 9, 2012 at 23:04

Daniel Roseman

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1 Comment

Yuji 'Tomita' Tomita Over a year ago

I'm not sure when this happened but his syntax works on 1.4A obj.filter(('key', 'value')). Caught me off guard too but it accepts key/value tuples. !?

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