mirror of
https://github.com/encode/django-rest-framework.git
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418 lines
14 KiB
Python
418 lines
14 KiB
Python
"""
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Renderers are used to serialize a View's output into specific media types.
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Django REST framework also provides HTML and PlainText renderers that help self-document the API,
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by serializing the output along with documentation regarding the View, output status and headers,
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and providing forms and links depending on the allowed methods, renderers and parsers on the View.
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"""
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from django import forms
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from django.conf import settings
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from django.core.serializers.json import DateTimeAwareJSONEncoder
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from django.template import RequestContext, loader
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from django.utils import simplejson as json
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from djangorestframework.compat import yaml
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from djangorestframework.utils import dict2xml, url_resolves
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from djangorestframework.utils.breadcrumbs import get_breadcrumbs
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from djangorestframework.utils.mediatypes import get_media_type_params, add_media_type_param, media_type_matches
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from djangorestframework import VERSION
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import string
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from urllib import quote_plus
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__all__ = (
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'BaseRenderer',
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'TemplateRenderer',
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'JSONRenderer',
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'JSONPRenderer',
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'DocumentingHTMLRenderer',
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'DocumentingXHTMLRenderer',
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'DocumentingPlainTextRenderer',
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'XMLRenderer',
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'YAMLRenderer'
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)
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class BaseRenderer(object):
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"""
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All renderers must extend this class, set the :attr:`media_type` attribute,
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and override the :meth:`render` method.
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"""
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_FORMAT_QUERY_PARAM = 'format'
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media_type = None
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format = None
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def __init__(self, view):
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self.view = view
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def can_handle_response(self, accept):
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"""
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Returns :const:`True` if this renderer is able to deal with the given
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*accept* media type.
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The default implementation for this function is to check the *accept*
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argument against the :attr:`media_type` attribute set on the class to see if
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they match.
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This may be overridden to provide for other behavior, but typically you'll
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instead want to just set the :attr:`media_type` attribute on the class.
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"""
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format = self.view.kwargs.get(self._FORMAT_QUERY_PARAM, None)
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if format is None:
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format = self.view.request.GET.get(self._FORMAT_QUERY_PARAM, None)
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if format is not None:
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return format == self.format
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return media_type_matches(self.media_type, accept)
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def render(self, obj=None, media_type=None):
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"""
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Given an object render it into a string.
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The requested media type is also passed to this method,
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as it may contain parameters relevant to how the parser
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should render the output.
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EG: ``application/json; indent=4``
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By default render simply returns the output as-is.
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Override this method to provide for other behavior.
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"""
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if obj is None:
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return ''
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return str(obj)
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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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def render(self, obj=None, media_type=None):
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"""
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Renders *obj* into serialized JSON.
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"""
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if obj is None:
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return ''
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# If the media type looks like 'application/json; indent=4', then
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# pretty print the result.
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indent = get_media_type_params(media_type).get('indent', None)
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sort_keys = False
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try:
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indent = max(min(int(indent), 8), 0)
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sort_keys = True
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except (ValueError, TypeError):
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indent = None
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return json.dumps(obj, cls=DateTimeAwareJSONEncoder, indent=indent, sort_keys=sort_keys)
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class JSONPRenderer(JSONRenderer):
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"""
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Renderer which serializes to JSONP
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"""
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media_type = 'application/json-p'
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format = 'json-p'
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renderer_class = JSONRenderer
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callback_parameter = 'callback'
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def _get_callback(self):
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return self.view.request.GET.get(self.callback_parameter, self.callback_parameter)
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def _get_renderer(self):
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return self.renderer_class(self.view)
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def render(self, obj=None, media_type=None):
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callback = self._get_callback()
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json = self._get_renderer().render(obj, media_type)
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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, obj=None, media_type=None):
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"""
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Renders *obj* into serialized XML.
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"""
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if obj is None:
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return ''
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return dict2xml(obj)
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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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def render(self, obj=None, media_type=None):
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"""
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Renders *obj* into serialized YAML.
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"""
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if obj is None:
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return ''
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return yaml.safe_dump(obj)
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class TemplateRenderer(BaseRenderer):
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"""
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A Base class provided for convenience.
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Render the object simply by using the given template.
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To create a template renderer, subclass this class, and set
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the :attr:`media_type` and :attr:`template` attributes.
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"""
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media_type = None
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template = None
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def __init__(self, view):
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super(TemplateRenderer, self).__init__(view)
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self.template = getattr(self.view, "template", self.template)
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def render(self, obj=None, media_type=None):
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"""
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Renders *obj* using the :attr:`template` specified on the class.
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"""
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if obj is None:
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return ''
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template = loader.get_template(self.template)
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context = RequestContext(self.view.request, {'object': obj})
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return template.render(context)
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class DocumentingTemplateRenderer(BaseRenderer):
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"""
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Base class for renderers used to self-document the API.
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Implementing classes should extend this class and set the template attribute.
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"""
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template = None
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def __init__(self, view):
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super(DocumentingTemplateRenderer, self).__init__(view)
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self.template = getattr(self.view, "template", self.template)
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def _get_content(self, view, request, obj, media_type):
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"""
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Get the content as if it had been rendered by a non-documenting renderer.
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(Typically this will be the content as it would have been if the Resource had been
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requested with an 'Accept: */*' header, although with verbose style formatting if appropriate.)
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"""
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# Find the first valid renderer and render the content. (Don't use another documenting renderer.)
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renderers = [renderer for renderer in view.renderers if not issubclass(renderer, DocumentingTemplateRenderer)]
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if not renderers:
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return '[No renderers were found]'
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media_type = add_media_type_param(media_type, 'indent', '4')
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content = renderers[0](view).render(obj, media_type)
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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 _get_form_instance(self, view, method):
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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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# Get the form instance if we have one bound to the input
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form_instance = None
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if method == getattr(view, 'method', view.request.method).lower():
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form_instance = getattr(view, 'bound_form_instance', None)
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if not form_instance and hasattr(view, 'get_bound_form'):
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# Otherwise if we have a response that is valid against the form then use that
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if view.response.has_content_body:
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try:
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form_instance = view.get_bound_form(view.response.cleaned_content, method=method)
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if form_instance and not form_instance.is_valid():
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form_instance = None
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except Exception:
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form_instance = None
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# If we still don't have a form instance then try to get an unbound form
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if not form_instance:
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try:
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form_instance = view.get_bound_form(method=method)
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except Exception:
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pass
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# If we still don't have a form instance then try to get an unbound form which can tunnel arbitrary content types
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if not form_instance:
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form_instance = self._get_generic_content_form(view)
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return form_instance
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def _get_generic_content_form(self, view):
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"""
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Returns a form that allows for arbitrary content types to be tunneled 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 getattr(view, '_USE_FORM_OVERLOADING', False):
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return None
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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, view):
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"""We don't know the names of the fields we want to set until the point the form is instantiated,
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as they are determined by the Resource the form is being created against.
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Add the fields dynamically."""
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super(GenericContentForm, self).__init__()
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contenttype_choices = [(media_type, media_type) for media_type in view._parsed_media_types]
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initial_contenttype = view._default_parser.media_type
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self.fields[view._CONTENTTYPE_PARAM] = forms.ChoiceField(label='Content Type',
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choices=contenttype_choices,
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initial=initial_contenttype)
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self.fields[view._CONTENT_PARAM] = forms.CharField(label='Content',
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widget=forms.Textarea)
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# If either of these reserved parameters are turned off then content tunneling is not possible
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if self.view._CONTENTTYPE_PARAM is None or self.view._CONTENT_PARAM is None:
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return None
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# Okey doke, let's do it
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return GenericContentForm(view)
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def get_name(self):
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try:
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return self.view.get_name()
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except AttributeError:
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return self.view.__doc__
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def get_description(self, html=None):
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if html is None:
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html = bool('html' in self.format)
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try:
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return self.view.get_description(html)
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except AttributeError:
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return self.view.__doc__
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def render(self, obj=None, media_type=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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content = self._get_content(self.view, self.view.request, obj, media_type)
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put_form_instance = self._get_form_instance(self.view, 'put')
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post_form_instance = self._get_form_instance(self.view, 'post')
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if url_resolves(settings.LOGIN_URL) and url_resolves(settings.LOGOUT_URL):
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login_url = "%s?next=%s" % (settings.LOGIN_URL, quote_plus(self.view.request.path))
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logout_url = "%s?next=%s" % (settings.LOGOUT_URL, quote_plus(self.view.request.path))
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else:
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login_url = None
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logout_url = None
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name = self.get_name()
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description = self.get_description()
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breadcrumb_list = get_breadcrumbs(self.view.request.path)
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template = loader.get_template(self.template)
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context = RequestContext(self.view.request, {
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'content': content,
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'view': self.view,
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'request': self.view.request,
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'response': self.view.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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'available_formats': self.view._rendered_formats,
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'put_form': put_form_instance,
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'post_form': post_form_instance,
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'FORMAT_PARAM': self._FORMAT_QUERY_PARAM,
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'METHOD_PARAM': getattr(self.view, '_METHOD_PARAM', None),
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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 self.view.response.status == 204:
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self.view.response.status = 200
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return ret
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class DocumentingHTMLRenderer(DocumentingTemplateRenderer):
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"""
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Renderer which provides a browsable HTML interface for an API.
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See the examples at http://api.django-rest-framework.org to see this in action.
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"""
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media_type = 'text/html'
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format = 'html'
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template = 'djangorestframework/api.html'
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class DocumentingXHTMLRenderer(DocumentingTemplateRenderer):
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"""
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Identical to DocumentingHTMLRenderer, except with an xhtml media type.
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We need this to be listed in preference to xml in order to return HTML to WebKit based browsers,
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given their Accept headers.
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"""
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media_type = 'application/xhtml+xml'
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format = 'xhtml'
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template = 'djangorestframework/api.html'
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class DocumentingPlainTextRenderer(DocumentingTemplateRenderer):
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"""
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Renderer that serializes the object with the default renderer, but also provides plain-text
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documentation of the returned status and headers, and of the resource's name and description.
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Useful for browsing an API with command line tools.
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"""
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media_type = 'text/plain'
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format = 'txt'
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template = 'djangorestframework/api.txt'
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DEFAULT_RENDERERS = (
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JSONRenderer,
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JSONPRenderer,
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DocumentingHTMLRenderer,
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DocumentingXHTMLRenderer,
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DocumentingPlainTextRenderer,
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XMLRenderer
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)
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if yaml:
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DEFAULT_RENDERERS += (YAMLRenderer, )
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else:
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YAMLRenderer = None
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