tastypie: filter many to many tables with multiple, ANDed values

Question

I have two tables (Movie and Genre) that are connected with a many to many relation using a crosstable (MovieGenre).

My models.py file looks like this:

class Genre( models.Model ):

    sName = models.CharField( max_length=176)
    [ .. ]

class Movie( models.Model ):

    sTitle = models.CharField( max_length=176)
    genre = models.ManyToManyField( Genre )
    [ .. ]

class MovieGenre( models.Model ):

    idMovie = models.ForeignKey( Movie )
    idGenre = models.ForeignKey( Genre )

I want to use tastypie to filter all movies of certain genres. E.g. show me all movies that are of genre Action, Thriller and SciFi.

My api.py looks like this:

class GenreResource(ModelResource):
    class Meta:
        queryset = Genre.objects.all()
        resource_name = 'genre'
        always_return_data = True
        include_resource_uri = False
        excludes = ['dtCreated', 'dtModified' ]
        authorization= Authorization()
        authentication = SessionAuthentication()
        filtering = {
            "id" : ALL,
        }


class MovieResource(ModelResource):
    genre = fields.ManyToManyField( 'app.api.GenreResource', 'genre', full=True )
    class Meta:
        queryset = Movie.objects.all()
        resource_name = 'movie'
        authorization= Authorization()
        authentication = SessionAuthentication()
        always_return_data = True
        include_resource_uri = False
        excludes = ['dtCreated', 'dtModified' ]
        filtering = {
            "sTitle" : ALL,
            "genre" : ALL_WITH_RELATIONS,
        }

My test data: Two movies (with genre ids) Matrix (1 & 3 ) Blade Runner (1 & 2 )

First I make a query on the title, as expected below query returns 1 result (namely Matrix):

   http://localhost:8000/api/v1/movie/?format=json&sTitle__icontains=a&sTitle__icontains=x

However, I get three results with the URL that should query the related genre table (two times Matrix and once Blade Runner) with this query:

    http://localhost:8000/api/v1/movie/?format=json&genre__id__in=3&genre__id__in=1

I would expect to get back only Matrix

I also tried to override apply_filters like so:

def apply_filters(self, request, applicable_filters):
    oList = super(ModelResource, self).apply_filters(request, applicable_filters)
    loQ = [Q(**{'sTitle__icontains': 'a'}), Q(**{'sTitle__icontains': 'x'})]
    # works as intended: one result
    loQ = [Q(**{'genre__id__in': '3'}) ]
    # results in one result (Matrix)

    loQ = [Q(**{'genre__id__in': '1'}), Q(**{'genre__id__in': '3'}) ]
    # results in no results!

    loQ = [Q(**{'genre__id__in': [ 1, 3]}) ]
    # results in two results Matrix and Blade Runner which is OK since obviously ORed
    oFilter = reduce( operator.and_, loQ )
    oList = oList.filter( oFilter ).distinct()
    return oList

Any idea to make this work?

Thanks for any idea...

Answer 1

Have you tried http://localhost:8000/api/v1/movie/?format=json&genre__id=3&genre__id=1

If I understand correctly, using __in that way would be like saying genre__id__in=[1, 3].