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https://github.com/encode/django-rest-framework.git
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516 lines
18 KiB
Python
516 lines
18 KiB
Python
"""
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Renderers are used to serialize a response into specific media types.
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They give us a generic way of being able to handle various media types
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on the response, such as JSON encoded data or HTML output.
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REST framework also provides an HTML renderer the renders the browsable API.
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"""
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from __future__ import unicode_literals
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import copy
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import string
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import json
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from django import forms
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from django.http.multipartparser import parse_header
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from django.template import RequestContext, loader, Template
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from django.utils.xmlutils import SimplerXMLGenerator
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from rest_framework.compat import StringIO
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from rest_framework.compat import six
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from rest_framework.compat import smart_text
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from rest_framework.compat import yaml
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from rest_framework.exceptions import ConfigurationError
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from rest_framework.settings import api_settings
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from rest_framework.request import clone_request
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from rest_framework.utils import encoders
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from rest_framework.utils.breadcrumbs import get_breadcrumbs
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from rest_framework.utils.formatting import get_view_name, get_view_description
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from rest_framework import exceptions, parsers, status, VERSION
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class BaseRenderer(object):
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"""
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All renderers should extend this class, setting the `media_type`
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and `format` attributes, and override the `.render()` method.
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"""
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media_type = None
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format = None
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def render(self, data, accepted_media_type=None, renderer_context=None):
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raise NotImplemented('Renderer class requires .render() to be implemented')
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class JSONRenderer(BaseRenderer):
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"""
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Renderer which serializes to json.
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"""
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media_type = 'application/json'
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format = 'json'
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encoder_class = encoders.JSONEncoder
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def render(self, data, accepted_media_type=None, renderer_context=None):
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"""
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Render `obj` into json.
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"""
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if data is None:
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return ''
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# If 'indent' is provided in the context, then pretty print the result.
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# E.g. If we're being called by the BrowseableAPIRenderer.
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renderer_context = renderer_context or {}
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indent = renderer_context.get('indent', None)
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if accepted_media_type:
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# If the media type looks like 'application/json; indent=4',
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# then pretty print the result.
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base_media_type, params = parse_header(accepted_media_type.encode('ascii'))
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indent = params.get('indent', indent)
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try:
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indent = max(min(int(indent), 8), 0)
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except (ValueError, TypeError):
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indent = None
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return json.dumps(data, cls=self.encoder_class, indent=indent)
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class JSONPRenderer(JSONRenderer):
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"""
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Renderer which serializes to json,
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wrapping the json output in a callback function.
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"""
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media_type = 'application/javascript'
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format = 'jsonp'
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callback_parameter = 'callback'
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default_callback = 'callback'
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def get_callback(self, renderer_context):
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"""
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Determine the name of the callback to wrap around the json output.
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"""
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request = renderer_context.get('request', None)
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params = request and request.QUERY_PARAMS or {}
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return params.get(self.callback_parameter, self.default_callback)
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def render(self, data, accepted_media_type=None, renderer_context=None):
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"""
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Renders into jsonp, wrapping the json output in a callback function.
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Clients may set the callback function name using a query parameter
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on the URL, for example: ?callback=exampleCallbackName
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"""
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renderer_context = renderer_context or {}
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callback = self.get_callback(renderer_context)
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json = super(JSONPRenderer, self).render(data, accepted_media_type,
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renderer_context)
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return "%s(%s);" % (callback, json)
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class XMLRenderer(BaseRenderer):
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"""
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Renderer which serializes to XML.
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"""
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media_type = 'application/xml'
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format = 'xml'
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def render(self, data, accepted_media_type=None, renderer_context=None):
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"""
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Renders *obj* into serialized XML.
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"""
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if data is None:
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return ''
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stream = StringIO()
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xml = SimplerXMLGenerator(stream, "utf-8")
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xml.startDocument()
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xml.startElement("root", {})
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self._to_xml(xml, data)
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xml.endElement("root")
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xml.endDocument()
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return stream.getvalue()
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def _to_xml(self, xml, data):
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if isinstance(data, (list, tuple)):
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for item in data:
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xml.startElement("list-item", {})
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self._to_xml(xml, item)
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xml.endElement("list-item")
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elif isinstance(data, dict):
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for key, value in six.iteritems(data):
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xml.startElement(key, {})
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self._to_xml(xml, value)
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xml.endElement(key)
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elif data is None:
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# Don't output any value
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pass
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else:
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xml.characters(smart_text(data))
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class YAMLRenderer(BaseRenderer):
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"""
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Renderer which serializes to YAML.
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"""
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media_type = 'application/yaml'
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format = 'yaml'
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encoder = encoders.SafeDumper
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def render(self, data, accepted_media_type=None, renderer_context=None):
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"""
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Renders *obj* into serialized YAML.
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"""
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assert yaml, 'YAMLRenderer requires pyyaml to be installed'
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if data is None:
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return ''
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return yaml.dump(data, stream=None, Dumper=self.encoder)
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class TemplateHTMLRenderer(BaseRenderer):
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"""
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An HTML renderer for use with templates.
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The data supplied to the Response object should be a dictionary that will
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be used as context for the template.
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The template name is determined by (in order of preference):
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1. An explicit `.template_name` attribute set on the response.
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2. An explicit `.template_name` attribute set on this class.
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3. The return result of calling `view.get_template_names()`.
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For example:
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data = {'users': User.objects.all()}
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return Response(data, template_name='users.html')
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For pre-rendered HTML, see StaticHTMLRenderer.
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"""
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media_type = 'text/html'
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format = 'html'
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template_name = None
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exception_template_names = [
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'%(status_code)s.html',
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'api_exception.html'
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]
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def render(self, data, accepted_media_type=None, renderer_context=None):
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"""
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Renders data to HTML, using Django's standard template rendering.
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The template name is determined by (in order of preference):
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1. An explicit .template_name set on the response.
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2. An explicit .template_name set on this class.
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3. The return result of calling view.get_template_names().
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"""
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renderer_context = renderer_context or {}
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view = renderer_context['view']
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request = renderer_context['request']
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response = renderer_context['response']
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if response.exception:
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template = self.get_exception_template(response)
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else:
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template_names = self.get_template_names(response, view)
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template = self.resolve_template(template_names)
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context = self.resolve_context(data, request, response)
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return template.render(context)
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def resolve_template(self, template_names):
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return loader.select_template(template_names)
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def resolve_context(self, data, request, response):
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if response.exception:
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data['status_code'] = response.status_code
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return RequestContext(request, data)
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def get_template_names(self, response, view):
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if response.template_name:
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return [response.template_name]
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elif self.template_name:
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return [self.template_name]
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elif hasattr(view, 'get_template_names'):
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return view.get_template_names()
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raise ConfigurationError('Returned a template response with no template_name')
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def get_exception_template(self, response):
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template_names = [name % {'status_code': response.status_code}
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for name in self.exception_template_names]
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try:
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# Try to find an appropriate error template
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return self.resolve_template(template_names)
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except Exception:
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# Fall back to using eg '404 Not Found'
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return Template('%d %s' % (response.status_code,
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response.status_text.title()))
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# Note, subclass TemplateHTMLRenderer simply for the exception behavior
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class StaticHTMLRenderer(TemplateHTMLRenderer):
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"""
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An HTML renderer class that simply returns pre-rendered HTML.
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The data supplied to the Response object should be a string representing
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the pre-rendered HTML content.
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For example:
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data = '<html><body>example</body></html>'
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return Response(data)
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For template rendered HTML, see TemplateHTMLRenderer.
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"""
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media_type = 'text/html'
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format = 'html'
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def render(self, data, accepted_media_type=None, renderer_context=None):
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renderer_context = renderer_context or {}
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response = renderer_context['response']
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if response and response.exception:
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request = renderer_context['request']
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template = self.get_exception_template(response)
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context = self.resolve_context(data, request, response)
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return template.render(context)
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return data
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class BrowsableAPIRenderer(BaseRenderer):
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"""
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HTML renderer used to self-document the API.
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"""
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media_type = 'text/html'
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format = 'api'
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template = 'rest_framework/api.html'
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def get_default_renderer(self, view):
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"""
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Return an instance of the first valid renderer.
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(Don't use another documenting renderer.)
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"""
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renderers = [renderer for renderer in view.renderer_classes
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if not issubclass(renderer, BrowsableAPIRenderer)]
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if not renderers:
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return None
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return renderers[0]()
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def get_content(self, renderer, data,
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accepted_media_type, renderer_context):
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"""
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Get the content as if it had been rendered by the default
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non-documenting renderer.
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"""
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if not renderer:
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return '[No renderers were found]'
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renderer_context['indent'] = 4
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content = renderer.render(data, accepted_media_type, renderer_context)
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if not all(char in string.printable for char in content):
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return '[%d bytes of binary content]'
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return content
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def show_form_for_method(self, view, method, request, obj):
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"""
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Returns True if a form should be shown for this method.
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"""
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if not method in view.allowed_methods:
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return # Not a valid method
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if not api_settings.FORM_METHOD_OVERRIDE:
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return # Cannot use form overloading
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try:
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view.check_permissions(clone_request(request, method))
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except exceptions.APIException:
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return False # Doesn't have permissions
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return True
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def serializer_to_form_fields(self, serializer):
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fields = {}
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for k, v in serializer.get_fields().items():
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if getattr(v, 'read_only', True):
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continue
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kwargs = {}
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kwargs['required'] = v.required
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#if getattr(v, 'queryset', None):
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# kwargs['queryset'] = v.queryset
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if getattr(v, 'choices', None) is not None:
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kwargs['choices'] = v.choices
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if getattr(v, 'regex', None) is not None:
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kwargs['regex'] = v.regex
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if getattr(v, 'widget', None):
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widget = copy.deepcopy(v.widget)
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kwargs['widget'] = widget
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if getattr(v, 'default', None) is not None:
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kwargs['initial'] = v.default
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kwargs['label'] = k
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fields[k] = v.form_field_class(**kwargs)
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return fields
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def get_form(self, view, method, request):
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"""
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Get a form, possibly bound to either the input or output data.
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In the absence on of the Resource having an associated form then
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provide a form that can be used to submit arbitrary content.
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"""
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obj = getattr(view, 'object', None)
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if not self.show_form_for_method(view, method, request, obj):
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return
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if method in ('DELETE', 'OPTIONS'):
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return True # Don't actually need to return a form
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if not getattr(view, 'get_serializer', None) or not parsers.FormParser in view.parser_classes:
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return
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serializer = view.get_serializer(instance=obj)
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fields = self.serializer_to_form_fields(serializer)
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# Creating an on the fly form see:
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# http://stackoverflow.com/questions/3915024/dynamically-creating-classes-python
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OnTheFlyForm = type(str("OnTheFlyForm"), (forms.Form,), fields)
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data = (obj is not None) and serializer.data or None
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form_instance = OnTheFlyForm(data)
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return form_instance
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def get_raw_data_form(self, view, method, request, media_types):
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"""
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Returns a form that allows for arbitrary content types to be tunneled
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via standard HTML forms.
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(Which are typically application/x-www-form-urlencoded)
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"""
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# If we're not using content overloading there's no point in supplying a generic form,
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# as the view won't treat the form's value as the content of the request.
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if not (api_settings.FORM_CONTENT_OVERRIDE
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and api_settings.FORM_CONTENTTYPE_OVERRIDE):
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return None
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# Check permissions
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obj = getattr(view, 'object', None)
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if not self.show_form_for_method(view, method, request, obj):
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return
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content_type_field = api_settings.FORM_CONTENTTYPE_OVERRIDE
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content_field = api_settings.FORM_CONTENT_OVERRIDE
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choices = [(media_type, media_type) for media_type in media_types]
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initial = media_types[0]
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# NB. http://jacobian.org/writing/dynamic-form-generation/
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class GenericContentForm(forms.Form):
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def __init__(self):
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super(GenericContentForm, self).__init__()
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self.fields[content_type_field] = forms.ChoiceField(
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label='Media type',
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choices=choices,
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initial=initial
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)
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self.fields[content_field] = forms.CharField(
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label='Content',
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widget=forms.Textarea
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)
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return GenericContentForm()
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def get_name(self, view):
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return get_view_name(view.__class__, getattr(view, 'suffix', None))
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def get_description(self, view):
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return get_view_description(view.__class__, html=True)
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def render(self, data, accepted_media_type=None, renderer_context=None):
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"""
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Renders *obj* using the :attr:`template` set on the class.
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The context used in the template contains all the information
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needed to self-document the response to this request.
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"""
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accepted_media_type = accepted_media_type or ''
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renderer_context = renderer_context or {}
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view = renderer_context['view']
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request = renderer_context['request']
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response = renderer_context['response']
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media_types = [parser.media_type for parser in view.parser_classes]
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renderer = self.get_default_renderer(view)
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content = self.get_content(renderer, data, accepted_media_type, renderer_context)
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put_form = self.get_form(view, 'PUT', request)
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post_form = self.get_form(view, 'POST', request)
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patch_form = self.get_form(view, 'PATCH', request)
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delete_form = self.get_form(view, 'DELETE', request)
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options_form = self.get_form(view, 'OPTIONS', request)
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raw_data_put_form = self.get_raw_data_form(view, 'PUT', request, media_types)
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raw_data_post_form = self.get_raw_data_form(view, 'POST', request, media_types)
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raw_data_patch_form = self.get_raw_data_form(view, 'PATCH', request, media_types)
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raw_data_put_or_patch_form = raw_data_put_form or raw_data_patch_form
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name = self.get_name(view)
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description = self.get_description(view)
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breadcrumb_list = get_breadcrumbs(request.path)
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template = loader.get_template(self.template)
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context = RequestContext(request, {
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'content': content,
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'view': view,
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'request': request,
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'response': response,
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'description': description,
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'name': name,
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'version': VERSION,
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'breadcrumblist': breadcrumb_list,
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'allowed_methods': view.allowed_methods,
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'available_formats': [renderer.format for renderer in view.renderer_classes],
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'put_form': put_form,
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'post_form': post_form,
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'patch_form': patch_form,
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'delete_form': delete_form,
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'options_form': options_form,
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'raw_data_put_form': raw_data_put_form,
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'raw_data_post_form': raw_data_post_form,
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'raw_data_patch_form': raw_data_patch_form,
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'raw_data_put_or_patch_form': raw_data_put_or_patch_form,
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'api_settings': api_settings
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})
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ret = template.render(context)
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# Munge DELETE Response code to allow us to return content
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# (Do this *after* we've rendered the template so that we include
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# the normal deletion response code in the output)
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if response.status_code == status.HTTP_204_NO_CONTENT:
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response.status_code = status.HTTP_200_OK
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return ret
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