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authorTom Christie2012-09-20 13:06:27 +0100
committerTom Christie2012-09-20 13:06:27 +0100
commit4b691c402707775c3048a90531024f3bc5be6f91 (patch)
tree3adfc54b0d8b70e4ea78edf7091f7827fa68f47b /rest_framework/negotiation.py
parenta1bcfbfe926621820832e32b0427601e1140b4f7 (diff)
downloaddjango-rest-framework-4b691c402707775c3048a90531024f3bc5be6f91.tar.bz2
Change package name: djangorestframework -> rest_framework
Diffstat (limited to 'rest_framework/negotiation.py')
-rw-r--r--rest_framework/negotiation.py74
1 files changed, 74 insertions, 0 deletions
diff --git a/rest_framework/negotiation.py b/rest_framework/negotiation.py
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+++ b/rest_framework/negotiation.py
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+from rest_framework import exceptions
+from rest_framework.settings import api_settings
+from rest_framework.utils.mediatypes import order_by_precedence
+
+
+class BaseContentNegotiation(object):
+ def negotiate(self, request, renderers, format=None, force=False):
+ raise NotImplementedError('.negotiate() must be implemented')
+
+
+class DefaultContentNegotiation(object):
+ settings = api_settings
+
+ def negotiate(self, request, renderers, format=None, force=False):
+ """
+ Given a request and a list of renderers, return a two-tuple of:
+ (renderer, media type).
+
+ If force is set, then suppress exceptions, and forcibly return a
+ fallback renderer and media_type.
+ """
+ try:
+ return self.unforced_negotiate(request, renderers, format)
+ except (exceptions.InvalidFormat, exceptions.NotAcceptable):
+ if force:
+ return (renderers[0], renderers[0].media_type)
+ raise
+
+ def unforced_negotiate(self, request, renderers, format=None):
+ """
+ As `.negotiate()`, but does not take the optional `force` agument,
+ or suppress exceptions.
+ """
+ # Allow URL style format override. eg. "?format=json
+ format = format or request.GET.get(self.settings.URL_FORMAT_OVERRIDE)
+
+ if format:
+ renderers = self.filter_renderers(renderers, format)
+
+ 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 filter_renderers(self, renderers, format):
+ """
+ If there is a '.json' style format suffix, filter the renderers
+ so that we only negotiation against those that accept that format.
+ """
+ renderers = [renderer for renderer in renderers
+ if renderer.can_handle_format(format)]
+ if not renderers:
+ raise exceptions.InvalidFormat(format)
+ return renderers
+
+ def get_accept_list(self, request):
+ """
+ Given the incoming request, return a tokenised list of media
+ type strings.
+
+ Allows URL style accept override. eg. "?accept=application/json"
+ """
+ header = request.META.get('HTTP_ACCEPT', '*/*')
+ header = request.GET.get(self.settings.URL_ACCEPT_OVERRIDE, header)
+ return [token.strip() for token in header.split(',')]