Python rest_framework.serializers 模块，HyperlinkedRelatedField() 实例源码

def get_object(self):
        """
        Incase the lookup is on an object that has been hyperlinked
        then update the queryset filter appropriately
        """
        if self.kwargs.get(self.lookup_field, None) is None:
            raise ParseError(
                'Expected URL keyword argument `%s`.' % self.lookup_field
            )
        queryset = self.filter_queryset(self.get_queryset())

        filter_kwargs = {}
        serializer = self.get_serializer()
        lookup_field = self.lookup_field

        if self.lookup_field in serializer.get_fields():
            k = serializer.get_fields()[self.lookup_field]
            if isinstance(k, serializers.HyperlinkedRelatedField):
                lookup_field = '%s__%s' % (self.lookup_field, k.lookup_field)

        filter_kwargs[lookup_field] = self.kwargs[self.lookup_field]

        obj = get_object_or_404(queryset, **filter_kwargs)

        # May raise a permission denied
        self.check_object_permissions(self.request, obj)

        return obj

def pre_save(self, obj):
        """
        Set any attributes on the object that are implicit in the request.
        """
        # pk and/or slug attributes are implicit in the URL.
        lookup = self.kwargs.get(self.lookup_field, None)
        pk = self.kwargs.get(self.pk_url_kwarg, None)
        slug = self.kwargs.get(self.slug_url_kwarg, None)
        slug_field = slug and self.slug_field or None

        if lookup:
            serializer = self.get_serializer()
            k = serializer.get_fields()[self.lookup_field]
            queryset = self.get_queryset()
            queryset = self.filter_queryset(queryset)
            if isinstance(k, serializers.HyperlinkedRelatedField):
                filter = {}
                lookup_field = '%s__%s' % (self.lookup_field, k.lookup_field)
                filter[lookup_field] = lookup
                k_obj = get_object_or_404(queryset, **filter)
                lookup = getattr(k_obj, self.lookup_field)
            setattr(obj, self.lookup_field, lookup)

        if pk:
            setattr(obj, 'pk', pk)

        if slug:
            setattr(obj, slug_field, slug)

        # Ensure we clean the attributes so that we don't eg return integer
        # pk using a string representation, as provided by the url conf kwarg.
        if hasattr(obj, 'full_clean'):
            exclude = mixins._get_validation_exclusions(
                obj, pk, slug_field, self.lookup_field)
            obj.full_clean(exclude)

def get_object(self):
        queryset = self.filter_queryset(self.get_queryset())
        filter_kwargs = {}
        serializer = self.get_serializer()
        lookup_fields = getattr(self, 'lookup_fields', [])

        for field in lookup_fields:
            lookup_field = field

            if lookup_field in serializer.get_fields():
                k = serializer.get_fields()[lookup_field]

                if isinstance(k, serializers.HyperlinkedRelatedField):
                    if k.source:
                        lookup_field = k.source
                    lookup_field = '%s__%s' % (lookup_field, k.lookup_field)

            if self.kwargs.get(field, None) is None:
                raise ParseError(
                    'Expected URL keyword argument `%s`.' % field
                )
            filter_kwargs[lookup_field] = self.kwargs[field]

        obj = get_object_or_404(queryset,  **filter_kwargs)

        # May raise a permission denied
        self.check_object_permissions(self.request, obj)

        return obj

def _get_related_fields(self, fields, id_field):
        return [k for (k, v) in fields
                if k != id_field
                and (isinstance(v, HyperlinkedRelatedField)
                or isinstance(v, HyperlinkedIdentityField)   
                or isinstance(v, ItemLinkField)
                or (isinstance(v, ManyRelatedField)
                    and isinstance(v.child_relation, HyperlinkedRelatedField)))]

def get_object(self, queryset=None):
        """Lookup user profile by pk or username"""
        if self.kwargs.get(self.lookup_field, None) is None:
            raise ParseError(
                'Expected URL keyword argument `%s`.' % self.lookup_field
            )
        if queryset is None:
            queryset = self.filter_queryset(self.get_queryset())

        serializer = self.get_serializer()
        lookup_field = self.lookup_field

        if self.lookup_field in serializer.get_fields():
            k = serializer.get_fields()[self.lookup_field]
            if isinstance(k, serializers.HyperlinkedRelatedField):
                lookup_field = '%s__%s' % (self.lookup_field, k.lookup_field)

        lookup = self.kwargs[self.lookup_field]
        filter_kwargs = {lookup_field: lookup}

        try:
            pk = int(lookup)
        except (TypeError, ValueError):
            pass
        else:
            filter_kwargs = {'user__pk': pk}

        obj = get_object_or_404(queryset, **filter_kwargs)

        # May raise a permission denied
        self.check_object_permissions(self.request, obj)

        return obj

def get_object(self, queryset=None):
        """
        Incase the lookup is on an object that has been hyperlinked
        then update the queryset filter appropriately
        """
        if self.kwargs.get(self.lookup_field, None) is None:
            raise ParseError(
                'Expected URL keyword argument `%s`.' % self.lookup_field
            )
        if queryset is None:
            queryset = self.filter_queryset(self.get_queryset())

        filter_kwargs = {}
        serializer = self.get_serializer()
        lookup_field = self.lookup_field

        if self.lookup_field in serializer.get_fields():
            k = serializer.get_fields()[self.lookup_field]
            if isinstance(k, serializers.HyperlinkedRelatedField):
                lookup_field = '%s__%s' % (self.lookup_field, k.lookup_field)

        filter_kwargs[lookup_field] = self.kwargs[self.lookup_field]

        obj = get_object_or_404(queryset, **filter_kwargs)

        # May raise a permission denied
        self.check_object_permissions(self.request, obj)

        return obj

def pre_save(self, obj):
        """
        Set any attributes on the object that are implicit in the request.
        """
        # pk and/or slug attributes are implicit in the URL.
        lookup = self.kwargs.get(self.lookup_field, None)
        pk = self.kwargs.get(self.pk_url_kwarg, None)
        slug = self.kwargs.get(self.slug_url_kwarg, None)
        slug_field = slug and self.slug_field or None

        if lookup:
            serializer = self.get_serializer()
            k = serializer.get_fields()[self.lookup_field]
            queryset = self.get_queryset()
            queryset = self.filter_queryset(queryset)
            if isinstance(k, serializers.HyperlinkedRelatedField):
                filter = {}
                lookup_field = '%s__%s' % (self.lookup_field, k.lookup_field)
                filter[lookup_field] = lookup
                k_obj = get_object_or_404(queryset, **filter)
                lookup = getattr(k_obj, self.lookup_field)
            setattr(obj, self.lookup_field, lookup)

        if pk:
            setattr(obj, 'pk', pk)

        if slug:
            setattr(obj, slug_field, slug)

        # Ensure we clean the attributes so that we don't eg return integer
        # pk using a string representation, as provided by the url conf kwarg.
        if hasattr(obj, 'full_clean'):
            exclude = mixins._get_validation_exclusions(
                obj, pk, slug_field, self.lookup_field)
            obj.full_clean(exclude)

def get_object(self, queryset=None):
        if queryset is None:
            queryset = self.filter_queryset(self.get_queryset())
        filter_kwargs = {}
        serializer = self.get_serializer()
        lookup_fields = getattr(self, 'lookup_fields', [])

        for field in lookup_fields:
            lookup_field = field

            if lookup_field in serializer.get_fields():
                k = serializer.get_fields()[lookup_field]

                if isinstance(k, serializers.HyperlinkedRelatedField):
                    if k.source:
                        lookup_field = k.source
                    lookup_field = '%s__%s' % (lookup_field, k.lookup_field)

            if self.kwargs.get(field, None) is None:
                raise ParseError(
                    'Expected URL keyword argument `%s`.' % field
                )
            filter_kwargs[lookup_field] = self.kwargs[field]

        obj = get_object_or_404(queryset,  **filter_kwargs)

        # May raise a permission denied
        self.check_object_permissions(self.request, obj)

        return obj

def to_internal_value(self, data):
        """ TODO - I've had to copy this method from HyperlinkedRelatedField purely
        so that it can deal with polymorphic models. This probably is not ideal.
        """
        try:
            http_prefix = data.startswith(('http:', 'https:'))
        except AttributeError:
            self.fail('incorrect_type', data_type=type(data).__name__)

        if http_prefix:
            # If needed convert absolute URLs to relative path
            data = urlparse.urlparse(data).path
            prefix = get_script_prefix()
            if data.startswith(prefix):
                data = '/' + data[len(prefix):]

        try:
            match = resolve(data)
        except Resolver404:
            self.fail('no_match')

        if self._serializer_is_polymorphic:
            # TODO - This is not really what we want. Need to make sure
            # that match.view_name points to a view which uses a subtype
            # serializer for this polymorphic serializer
            self.view_name = match.view_name

        if match.view_name != self.view_name:
            self.fail('incorrect_match')

        try:
            return self.get_object(match.view_name, match.args, match.kwargs)
        except (ObjectDoesNotExist, TypeError, ValueError):
            self.fail('does_not_exist')