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| author | Tom Christie | 2012-09-20 13:06:27 +0100 | 
|---|---|---|
| committer | Tom Christie | 2012-09-20 13:06:27 +0100 | 
| commit | 4b691c402707775c3048a90531024f3bc5be6f91 (patch) | |
| tree | 3adfc54b0d8b70e4ea78edf7091f7827fa68f47b /rest_framework/negotiation.py | |
| parent | a1bcfbfe926621820832e32b0427601e1140b4f7 (diff) | |
| download | django-rest-framework-4b691c402707775c3048a90531024f3bc5be6f91.tar.bz2 | |
Change package name: djangorestframework -> rest_framework
Diffstat (limited to 'rest_framework/negotiation.py')
| -rw-r--r-- | rest_framework/negotiation.py | 74 | 
1 files changed, 74 insertions, 0 deletions
| diff --git a/rest_framework/negotiation.py b/rest_framework/negotiation.py new file mode 100644 index 00000000..0d3b368c --- /dev/null +++ b/rest_framework/negotiation.py @@ -0,0 +1,74 @@ +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(',')] | 
