Moved content negotiation out of response. Nicer exception handling now.

1 files changed, 63 insertions, 0 deletions

diff --git a/djangorestframework/contentnegotiation.py b/djangorestframework/contentnegotiation.py
new file mode 100644
index 00000000..223919ef
--- /dev/null
+++ b/djangorestframework/contentnegotiation.py
@@ -0,0 +1,63 @@
+from djangorestframework import exceptions
+from djangorestframework.settings import api_settings
+from djangorestframework.utils.mediatypes import order_by_precedence
+import re
+
+MSIE_USER_AGENT_REGEX = re.compile(r'^Mozilla/[0-9]+\.[0-9]+ \([^)]*; MSIE [0-9]+\.[0-9]+[a-z]?;[^)]*\)(?!.* Opera )')
+
+
+class BaseContentNegotiation(object):
+    def determine_renderer(self, request, renderers):
+        raise NotImplementedError('.determine_renderer() must be implemented')
+
+
+class DefaultContentNegotiation(object):
+    settings = api_settings
+
+    def negotiate(self, request, renderers):
+        """
+        Given a request and a list of renderers, return a two-tuple of:
+        (renderer, media type).
+        """
+        accepts = self.get_accept_list(request)
+
+        # Check the acceptable media types against each renderer,
+        # attempting more specific media types first
+        # NB. The inner loop here isn't as bad as it first looks :)
+        #     Worst case is we're looping over len(accept_list) * len(self.renderers)
+        for media_type_set in order_by_precedence(accepts):
+            for renderer in renderers:
+                for media_type in media_type_set:
+                    if renderer.can_handle_media_type(media_type):
+                        return renderer, media_type
+
+        raise exceptions.NotAcceptable(available_renderers=renderers)
+
+    def get_accept_list(self, request):
+        """
+        Given the incoming request, return a tokenised list of
+        media type strings.
+        """
+        if self.settings.URL_ACCEPT_OVERRIDE:
+            # URL style accept override.  eg.  "?accept=application/json"
+            override = request.GET.get(self.settings.URL_ACCEPT_OVERRIDE)
+            if override:
+                return [override]
+
+        if (self.settings.IGNORE_MSIE_ACCEPT_HEADER and
+            'HTTP_USER_AGENT' in request.META and
+            MSIE_USER_AGENT_REGEX.match(request.META['HTTP_USER_AGENT']) and
+            request.META.get('HTTP_X_REQUESTED_WITH', '').lower() != 'xmlhttprequest'):
+            # Ignore MSIE's broken accept behavior except for AJAX requests
+            # and do something sensible instead
+            return ['text/html', '*/*']
+
+        if 'HTTP_ACCEPT' in request.META:
+            # Standard HTTP Accept negotiation
+            # Accept header specified
+            tokens = request.META['HTTP_ACCEPT'].split(',')
+            return [token.strip() for token in tokens]
+
+        # Standard HTTP Accept negotiation
+        # No accept header specified
+        return ['*/*']