How do I construct an AND query on the same field in the URL of TastyPie?

Question

I want to filter results in the tastypie to get results that conform to both of two filters on the same field.

So if I have a simple model like this...

class Item(models.Model):
    name = models.CharField(max_length=255)
    description = models.TextField()

With a ModelResource...

class ItemResource(ModelResource):
    ...
    class Meta():
        queryset = Item.objects.all()
        resource_name = 'item'
        filtering = {'name': ALL, 'description': ALL}

I can easily construct 'AND' queries in the url of tastypie:

/api/v1/item/?name__contains=hello&description__contains=foo

But if I want to construct an AND operator on the same field, it only takes the second argument and ignores the first. That is,

/api/v1/item/?name__contains=hello&name__contains=world

returns resources whose name field contains 'world' but not those whose name field contains BOTH 'hello' and 'world'.

I understand how to do this directly in django:

Item.objects.filter(name__contains='hello').filter(name__contains='world')

But how do I construct this kind of a query in the URL of the tastypie?

Answer 1

I'm using the below. It will give you support for name__contains=hello,world. And you could also do negations name__contains!=foo.

def build_filters(self, filters=None):

    """
    Adds support for negation filtering
    """
    if not filters:
        return filters

    applicable_filters = {}
    self.filters = filters

    # Normal filtering
    filter_params = dict([(x, filters[x]) for x in filter(lambda x: not x.endswith('!'), filters)])
    applicable_filters['filter'] = super(MainBaseResource, self).build_filters(filter_params)

    # Exclude filtering
    exclude_params = dict([(x[:-1], filters[x]) for x in filter(lambda x: x.endswith('!'), filters)])
    applicable_filters['exclude'] = super(MainBaseResource, self).build_filters(exclude_params)

    return applicable_filters

def apply_filters(self, request, applicable_filters):

    """
    Adds support for:
    1. negation filtering: value_date__year!=2013
    2. multiple filtering value_date__year=2013,2012
    """

    from django.db.models import Q
    import operator
    from types import *

    objects = self.get_object_list(request)

    f = applicable_filters.get('filter')

    if f:
        # Q Filters for multiple values (1,2,3 etc)
        q_filters = []
        for key, val in f.iteritems():
            string = str(val)
            if ',' in string:
                for excl_filter in string.split(','):
                    q_filters.append((key, excl_filter))

        q_list = [Q(x) for x in q_filters]
        for x in q_filters:
            try:
                del f[x[0]]
            except:
                pass
        if q_list:
            objects = objects.filter(reduce(operator.or_, q_list), **f)
        else:
            objects = objects.filter(**f)

    e = applicable_filters.get('exclude')
    if e:
        objects = objects.exclude(**e)
    return objects