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https://github.com/encode/django-rest-framework.git
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636 lines
22 KiB
Python
636 lines
22 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 json
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from django import forms
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from django.core.exceptions import ImproperlyConfigured
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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.test.client import encode_multipart
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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.settings import api_settings
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from rest_framework.request import is_form_media_type, override_method
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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 import exceptions, 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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charset = 'utf-8'
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render_style = 'text'
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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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Applies JSON's backslash-u character escaping for non-ascii characters.
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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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ensure_ascii = True
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charset = None
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# JSON is a binary encoding, that can be encoded as utf-8, utf-16 or utf-32.
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# See: http://www.ietf.org/rfc/rfc4627.txt
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# Also: http://lucumr.pocoo.org/2013/7/19/application-mimetypes-and-encodings/
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def render(self, data, accepted_media_type=None, renderer_context=None):
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"""
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Render `data` into JSON.
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"""
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if data is None:
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return bytes()
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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 BrowsableAPIRenderer.
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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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ret = json.dumps(data, cls=self.encoder_class,
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indent=indent, ensure_ascii=self.ensure_ascii)
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# On python 2.x json.dumps() returns bytestrings if ensure_ascii=True,
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# but if ensure_ascii=False, the return type is underspecified,
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# and may (or may not) be unicode.
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# On python 3.x json.dumps() returns unicode strings.
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if isinstance(ret, six.text_type):
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return bytes(ret.encode('utf-8'))
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return ret
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class UnicodeJSONRenderer(JSONRenderer):
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ensure_ascii = False
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"""
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Renderer which serializes to JSON.
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Does *not* apply JSON's character escaping for non-ascii characters.
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"""
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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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charset = 'utf-8'
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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 callback.encode(self.charset) + b'(' + json + b');'
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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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charset = 'utf-8'
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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, self.charset)
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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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charset = 'utf-8'
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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, encoding=self.charset, 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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charset = 'utf-8'
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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 ImproperlyConfigured('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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charset = 'utf-8'
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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 HTMLFormRenderer(BaseRenderer):
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"""
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Renderers serializer data into an HTML form.
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If the serializer was instantiated without an object then this will
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return an HTML form not bound to any object,
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otherwise it will return an HTML form with the appropriate initial data
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populated from the object.
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Note that rendering of field and form errors is not currently supported.
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"""
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media_type = 'text/html'
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format = 'form'
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template = 'rest_framework/form.html'
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charset = 'utf-8'
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def data_to_form_fields(self, data):
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fields = {}
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for key, val in data.fields.items():
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if getattr(val, 'read_only', True):
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continue
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kwargs = {}
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kwargs['required'] = val.required
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#if getattr(v, 'queryset', None):
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# kwargs['queryset'] = v.queryset
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if getattr(val, 'choices', None) is not None:
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kwargs['choices'] = val.choices
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if getattr(val, 'regex', None) is not None:
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kwargs['regex'] = val.regex
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if getattr(val, 'widget', None):
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widget = copy.deepcopy(val.widget)
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kwargs['widget'] = widget
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if getattr(val, 'default', None) is not None:
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kwargs['initial'] = val.default
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if getattr(val, 'label', None) is not None:
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kwargs['label'] = val.label
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if getattr(val, 'help_text', None) is not None:
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kwargs['help_text'] = val.help_text
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fields[key] = val.form_field_class(**kwargs)
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return fields
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def render(self, data, accepted_media_type=None, renderer_context=None):
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"""
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Render serializer data and return an HTML form, as a string.
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"""
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# The HTMLFormRenderer currently uses something of a hack to render
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# the content, by translating each of the serializer fields into
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# an html form field, creating a dynamic form using those fields,
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# and then rendering that form.
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# This isn't strictly neccessary, as we could render the serilizer
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# fields to HTML directly. The implementation is historical and will
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# likely change at some point.
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self.renderer_context = renderer_context or {}
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request = renderer_context['request']
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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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fields = self.data_to_form_fields(data)
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DynamicForm = type(str('DynamicForm'), (forms.Form,), fields)
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data = None if data.empty else data
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template = loader.get_template(self.template)
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context = RequestContext(request, {'form': DynamicForm(data)})
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return template.render(context)
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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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charset = 'utf-8'
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form_renderer_class = HTMLFormRenderer
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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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render_style = getattr(renderer, 'render_style', 'text')
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assert render_style in ['text', 'binary'], 'Expected .render_style ' \
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'"text" or "binary", but got "%s"' % render_style
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if render_style == 'binary':
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return '[%d bytes of binary content]' % len(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(request)
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if obj is not None:
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view.check_object_permissions(request, obj)
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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 get_rendered_html_form(self, view, method, request):
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"""
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Return a string representing a rendered HTML form, possibly bound to
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either the input or output data.
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In the absence of the View having an associated form then return None.
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"""
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with override_method(view, request, method) as request:
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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)
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or not any(is_form_media_type(parser.media_type) for parser in view.parser_classes)):
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return
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serializer = view.get_serializer(instance=obj)
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data = serializer.data
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form_renderer = self.form_renderer_class()
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return form_renderer.render(data, self.accepted_media_type, self.renderer_context)
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def get_raw_data_form(self, view, method, request):
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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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with override_method(view, request, method) as request:
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# If we're not using content overloading there's no point in
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# supplying a generic form, as the view won't treat the form's
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# 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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# If possible, serialize the initial content for the generic form
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default_parser = view.parser_classes[0]
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renderer_class = getattr(default_parser, 'renderer_class', None)
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if (hasattr(view, 'get_serializer') and renderer_class):
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# View has a serializer defined and parser class has a
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# corresponding renderer that can be used to render the data.
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# Get a read-only version of the serializer
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serializer = view.get_serializer(instance=obj)
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for field_name, field in serializer.fields.items():
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if field.read_only:
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del serializer.fields[field_name]
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# Render the raw data content
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renderer = renderer_class()
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accepted = self.accepted_media_type
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context = self.renderer_context.copy()
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context['indent'] = 4
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content = renderer.render(serializer.data, accepted, context)
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else:
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content = None
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# Generate a generic form that includes a content type field,
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# and a content field.
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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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media_types = [parser.media_type for parser in view.parser_classes]
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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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initial=content
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)
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return GenericContentForm()
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def get_name(self, view):
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return view.get_view_name()
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def get_description(self, view):
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return view.get_view_description(html=True)
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def get_breadcrumbs(self, request):
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return get_breadcrumbs(request.path)
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def render(self, data, accepted_media_type=None, renderer_context=None):
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"""
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Render the HTML for the browsable API representation.
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"""
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self.accepted_media_type = accepted_media_type or ''
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self.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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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_rendered_html_form(view, 'PUT', request)
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post_form = self.get_rendered_html_form(view, 'POST', request)
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patch_form = self.get_rendered_html_form(view, 'PATCH', request)
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delete_form = self.get_rendered_html_form(view, 'DELETE', request)
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options_form = self.get_rendered_html_form(view, 'OPTIONS', request)
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raw_data_put_form = self.get_raw_data_form(view, 'PUT', request)
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raw_data_post_form = self.get_raw_data_form(view, 'POST', request)
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raw_data_patch_form = self.get_raw_data_form(view, 'PATCH', request)
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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 = self.get_breadcrumbs(request)
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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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|
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class MultiPartRenderer(BaseRenderer):
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media_type = 'multipart/form-data; boundary=BoUnDaRyStRiNg'
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format = 'multipart'
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charset = 'utf-8'
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BOUNDARY = 'BoUnDaRyStRiNg'
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def render(self, data, accepted_media_type=None, renderer_context=None):
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return encode_multipart(self.BOUNDARY, data)
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