Remove Parser.can_handle_request()

rest_framework/negotiation.py

@@ -11,6 +11,16 @@ class BaseContentNegotiation(object):
 class DefaultContentNegotiation(object):
     settings = api_settings
 
+    def select_parser(self, parsers, media_type):
+        """
+        Given a list of parsers and a media type, return the appropriate
+        parser to handle the incoming request.
+        """
+        for parser in parsers:
+            if media_type_matches(parser.media_type, media_type):
+                return parser
+        return None
+
     def negotiate(self, request, renderers, format=None, force=False):
         """
         Given a request and a list of renderers, return a two-tuple of:

rest_framework/parsers.py

@@ -15,11 +15,9 @@ from django.http import QueryDict
 from django.http.multipartparser import MultiPartParser as DjangoMultiPartParser
 from django.http.multipartparser import MultiPartParserError
 from django.utils import simplejson as json
-from rest_framework.compat import yaml
+from rest_framework.compat import yaml, ETParseError
 from rest_framework.exceptions import ParseError
-from rest_framework.utils.mediatypes import media_type_matches
 from xml.etree import ElementTree as ET
-from rest_framework.compat import ETParseError
 from xml.parsers.expat import ExpatError
 import datetime
 import decimal
@@ -40,19 +38,6 @@ class BaseParser(object):
 
     media_type = None
 
-    def can_handle_request(self, content_type):
-        """
-        Returns :const:`True` if this parser is able to deal with the given *content_type*.
-
-        The default implementation for this function is to check the *content_type*
-        argument against the :attr:`media_type` attribute set on the class to see if
-        they match.
-
-        This may be overridden to provide for other behavior, but typically you'll
-        instead want to just set the :attr:`media_type` attribute on the class.
-        """
-        return media_type_matches(self.media_type, content_type)
-
     def parse(self, string_or_stream, **opts):
         """
         The main entry point to parsers.  This is a light wrapper around

rest_framework/request.py

@@ -34,8 +34,8 @@ def clone_request(request, method):
     HTTP method.  Used for checking permissions against other methods.
     """
     ret = Request(request._request,
-                  request.parser_classes,
-                  request.authentication_classes)
+                  request.parsers,
+                  request.authenticators)
     ret._data = request._data
     ret._files = request._files
     ret._content_type = request._content_type
@@ -60,27 +60,20 @@ class Request(object):
     _CONTENT_PARAM = api_settings.FORM_CONTENT_OVERRIDE
     _CONTENTTYPE_PARAM = api_settings.FORM_CONTENTTYPE_OVERRIDE
 
-    def __init__(self, request, parser_classes=None, authentication_classes=None):
+    def __init__(self, request, parsers=None, authenticators=None,
+                 negotiator=None):
         self._request = request
-        self.parser_classes = parser_classes or ()
-        self.authentication_classes = authentication_classes or ()
+        self.parsers = parsers or ()
+        self.authenticators = authenticators or ()
+        self.negotiator = negotiator or self._default_negotiator()
         self._data = Empty
         self._files = Empty
         self._method = Empty
         self._content_type = Empty
         self._stream = Empty
 
-    def get_parsers(self):
-        """
-        Instantiates and returns the list of parsers the request will use.
-        """
-        return [parser() for parser in self.parser_classes]
-
-    def get_authentications(self):
-        """
-        Instantiates and returns the list of parsers the request will use.
-        """
-        return [authentication() for authentication in self.authentication_classes]
+    def _default_negotiator(self):
+        return api_settings.DEFAULT_CONTENT_NEGOTIATION()
 
     @property
     def method(self):
@@ -254,26 +247,27 @@ class Request(object):
         if self.stream is None or self.content_type is None:
             return (None, None)
 
-        for parser in self.get_parsers():
-            if parser.can_handle_request(self.content_type):
-                parsed = parser.parse(self.stream, meta=self.META,
-                                      upload_handlers=self.upload_handlers)
-                # Parser classes may return the raw data, or a
-                # DataAndFiles object.  Unpack the result as required.
-                try:
-                    return (parsed.data, parsed.files)
-                except AttributeError:
-                    return (parsed, None)
+        parser = self.negotiator.select_parser(self.parsers, self.content_type)
+
+        if not parser:
+            raise exceptions.UnsupportedMediaType(self._content_type)
 
-        raise exceptions.UnsupportedMediaType(self._content_type)
+        parsed = parser.parse(self.stream, meta=self.META,
+                              upload_handlers=self.upload_handlers)
+        # Parser classes may return the raw data, or a
+        # DataAndFiles object.  Unpack the result as required.
+        try:
+            return (parsed.data, parsed.files)
+        except AttributeError:
+            return (parsed, None)
 
     def _authenticate(self):
         """
         Attempt to authenticate the request using each authentication instance in turn.
         Returns a two-tuple of (user, authtoken).
         """
-        for authentication in self.get_authentications():
-            user_auth_tuple = authentication.authenticate(self)
+        for authenticator in self.authenticators:
+            user_auth_tuple = authenticator.authenticate(self)
             if not user_auth_tuple is None:
                 return user_auth_tuple
         return self._not_authenticated()

rest_framework/tests/decorators.py

@@ -65,7 +65,9 @@ class DecoratorTestCase(TestCase):
         @api_view(['GET'])
         @parser_classes([JSONParser])
         def view(request):
-            self.assertEqual(request.parser_classes, [JSONParser])
+            self.assertEqual(len(request.parsers), 1)
+            self.assertTrue(isinstance(request.parsers[0],
+                                       JSONParser))
             return Response({})
 
         request = self.factory.get('/')
@@ -76,7 +78,9 @@ class DecoratorTestCase(TestCase):
         @api_view(['GET'])
         @authentication_classes([BasicAuthentication])
         def view(request):
-            self.assertEqual(request.authentication_classes, [BasicAuthentication])
+            self.assertEqual(len(request.authenticators), 1)
+            self.assertTrue(isinstance(request.authenticators[0],
+                                       BasicAuthentication))
             return Response({})
 
         request = self.factory.get('/')

rest_framework/tests/request.py

@@ -61,7 +61,7 @@ class TestContentParsing(TestCase):
         """
         data = {'qwerty': 'uiop'}
         request = Request(factory.post('/', data))
-        request.parser_classes = (FormParser, MultiPartParser)
+        request.parsers = (FormParser(), MultiPartParser())
         self.assertEqual(request.DATA.items(), data.items())
 
     def test_request_DATA_with_text_content(self):
@@ -72,7 +72,7 @@ class TestContentParsing(TestCase):
         content = 'qwerty'
         content_type = 'text/plain'
         request = Request(factory.post('/', content, content_type=content_type))
-        request.parser_classes = (PlainTextParser,)
+        request.parsers = (PlainTextParser(),)
         self.assertEqual(request.DATA, content)
 
     def test_request_POST_with_form_content(self):
@@ -81,7 +81,7 @@ class TestContentParsing(TestCase):
         """
         data = {'qwerty': 'uiop'}
         request = Request(factory.post('/', data))
-        request.parser_classes = (FormParser, MultiPartParser)
+        request.parsers = (FormParser(), MultiPartParser())
         self.assertEqual(request.POST.items(), data.items())
 
     def test_standard_behaviour_determines_form_content_PUT(self):
@@ -99,7 +99,7 @@ class TestContentParsing(TestCase):
         else:
             request = Request(factory.put('/', data))
 
-        request.parser_classes = (FormParser, MultiPartParser)
+        request.parsers = (FormParser(), MultiPartParser())
         self.assertEqual(request.DATA.items(), data.items())
 
     def test_standard_behaviour_determines_non_form_content_PUT(self):
@@ -110,7 +110,7 @@ class TestContentParsing(TestCase):
         content = 'qwerty'
         content_type = 'text/plain'
         request = Request(factory.put('/', content, content_type=content_type))
-        request.parser_classes = (PlainTextParser, )
+        request.parsers = (PlainTextParser(), )
         self.assertEqual(request.DATA, content)
 
     def test_overloaded_behaviour_allows_content_tunnelling(self):
@@ -124,7 +124,7 @@ class TestContentParsing(TestCase):
             Request._CONTENTTYPE_PARAM: content_type
         }
         request = Request(factory.post('/', data))
-        request.parser_classes = (PlainTextParser, )
+        request.parsers = (PlainTextParser(), )
         self.assertEqual(request.DATA, content)
 
     # def test_accessing_post_after_data_form(self):

rest_framework/views.py

@@ -70,6 +70,7 @@ class APIView(View):
         as an attribute on the callable function.  This allows us to discover
         information about the view when we do URL reverse lookups.
         """
+        # TODO: deprecate?
         view = super(APIView, cls).as_view(**initkwargs)
         view.cls_instance = cls(**initkwargs)
         return view
@@ -84,6 +85,7 @@ class APIView(View):
 
     @property
     def default_response_headers(self):
+        # TODO: Only vary by accept if multiple renderers
         return {
             'Allow': ', '.join(self.allowed_methods),
             'Vary': 'Accept'
@@ -94,6 +96,7 @@ class APIView(View):
         Return the resource or view class name for use as this view's name.
         Override to customize.
         """
+        # TODO: deprecate?
         name = self.__class__.__name__
         name = _remove_trailing_string(name, 'View')
         return _camelcase_to_spaces(name)
@@ -103,6 +106,7 @@ class APIView(View):
         Return the resource or view docstring for use as this view's description.
         Override to customize.
         """
+        # TODO: deprecate?
         description = self.__doc__ or ''
         description = _remove_leading_indent(description)
         if html:
@@ -113,6 +117,7 @@ class APIView(View):
         """
         Apply HTML markup to the description of this view.
         """
+        # TODO: deprecate?
         if apply_markdown:
             description = apply_markdown(description)
         else:
@@ -137,6 +142,8 @@ class APIView(View):
         """
         raise exceptions.Throttled(wait)
 
+    # API policy instantiation methods
+
     def get_format_suffix(self, **kwargs):
         """
         Determine if the request includes a '.json' style format suffix
@@ -144,12 +151,24 @@ class APIView(View):
         if self.settings.FORMAT_SUFFIX_KWARG:
             return kwargs.get(self.settings.FORMAT_SUFFIX_KWARG)
 
-    def get_renderers(self, format=None):
+    def get_renderers(self):
         """
         Instantiates and returns the list of renderers that this view can use.
         """
         return [renderer(self) for renderer in self.renderer_classes]
 
+    def get_parsers(self):
+        """
+        Instantiates and returns the list of renderers that this view can use.
+        """
+        return [parser() for parser in self.parser_classes]
+
+    def get_authenticators(self):
+        """
+        Instantiates and returns the list of renderers that this view can use.
+        """
+        return [auth() for auth in self.authentication_classes]
+
     def get_permissions(self):
         """
         Instantiates and returns the list of permissions that this view requires.
@@ -166,7 +185,11 @@ class APIView(View):
         """
         Instantiate and return the content negotiation class to use.
         """
-        return self.content_negotiation_class()
+        if not getattr(self, '_negotiator', None):
+            self._negotiator = self.content_negotiation_class()
+        return self._negotiator
+
+    # API policy implementation methods
 
     def perform_content_negotiation(self, request, force=False):
         """
@@ -193,19 +216,24 @@ class APIView(View):
             if not throttle.allow_request(request):
                 self.throttled(request, throttle.wait())
 
+    # Dispatch methods
+
     def initialize_request(self, request, *args, **kargs):
         """
         Returns the initial request object.
         """
-        return Request(request, parser_classes=self.parser_classes,
-                       authentication_classes=self.authentication_classes)
+        return Request(request,
+                       parsers=self.get_parsers(),
+                       authenticators=self.get_authenticators(),
+                       negotiator=self.get_content_negotiator())
 
     def initial(self, request, *args, **kwargs):
         """
-        Runs anything that needs to occur prior to calling the method handlers.
+        Runs anything that needs to occur prior to calling the method handler.
         """
         self.format_kwarg = self.get_format_suffix(**kwargs)
 
+        # Ensure that the incoming request is permitted
         if not self.has_permission(request):
             self.permission_denied(request)
         self.check_throttles(request)