""" The :mod:`request` module provides a :class:`Request` class used to wrap the standard `request` object received in all the views. The wrapped request then offers a richer API, in particular : - content automatically parsed according to `Content-Type` header, and available as :meth:`.DATA` - full support of PUT method, including support for file uploads - form overloading of HTTP method, content type and content """ from StringIO import StringIO from django.contrib.auth.models import AnonymousUser from djangorestframework.exceptions import UnsupportedMediaType from djangorestframework.utils.mediatypes import is_form_media_type __all__ = ('Request',) class Empty(object): """ Placeholder for unset attributes. Cannot use `None`, as that may be a valid value. """ pass def _hasattr(obj, name): return not getattr(obj, name) is Empty class Request(object): """ Wrapper allowing to enhance a standard `HttpRequest` instance. Kwargs: - request(HttpRequest). The original request instance. - parsers(list/tuple). The parsers to use for parsing the request content. - authentications(list/tuple). The authentications used to try authenticating the request's user. """ _USE_FORM_OVERLOADING = True _METHOD_PARAM = '_method' _CONTENTTYPE_PARAM = '_content_type' _CONTENT_PARAM = '_content' def __init__(self, request, parsers=None, authentication=None): self._request = request self.parsers = parsers or () self.authentication = authentication or () self._data = Empty self._files = Empty self._method = Empty self._content_type = Empty self._stream = Empty def get_parsers(self): """ Instantiates and returns the list of parsers the request will use. """ return [parser() for parser in self.parsers] def get_authentications(self): """ Instantiates and returns the list of parsers the request will use. """ return [authentication() for authentication in self.authentication] @property def method(self): """ Returns the HTTP method. This allows the `method` to be overridden by using a hidden `form` field on a form POST request. """ if not _hasattr(self, '_method'): self._load_method_and_content_type() return self._method @property def content_type(self): """ Returns the content type header. This should be used instead of ``request.META.get('HTTP_CONTENT_TYPE')``, as it allows the content type to be overridden by using a hidden form field on a form POST request. """ if not _hasattr(self, '_content_type'): self._load_method_and_content_type() return self._content_type @property def stream(self): """ Returns an object that may be used to stream the request content. """ if not _hasattr(self, '_stream'): self._load_stream() return self._stream @property def DATA(self): """ Parses the request body and returns the data. Similar to ``request.POST``, except that it handles arbitrary parsers, and also works on methods other than POST (eg PUT). """ if not _hasattr(self, '_data'): self._load_data_and_files() return self._data @property def FILES(self): """ Parses the request body and returns the files. Similar to ``request.FILES``, except that it handles arbitrary parsers, and also works on methods other than POST (eg PUT). """ if not _hasattr(self, '_files'): self._load_data_and_files() return self._files @property def user(self): """ Returns the :obj:`user` for the current request, authenticated with the set of :class:`authentication` instances applied to the :class:`Request`. """ if not hasattr(self, '_user'): self._user = self._authenticate() return self._user def _load_data_and_files(self): """ Parses the request content into self.DATA and self.FILES. """ if not _hasattr(self, '_content_type'): self._load_method_and_content_type() if not _hasattr(self, '_data'): self._data, self._files = self._parse() def _load_method_and_content_type(self): """ Sets the method and content_type, and then check if they've been overridden. """ self._content_type = self.META.get('HTTP_CONTENT_TYPE', self.META.get('CONTENT_TYPE', '')) self._perform_form_overloading() # if the HTTP method was not overloaded, we take the raw HTTP method if not _hasattr(self, '_method'): self._method = self._request.method def _load_stream(self): try: content_length = int(self.META.get('CONTENT_LENGTH', self.META.get('HTTP_CONTENT_LENGTH'))) except (ValueError, TypeError): content_length = 0 if content_length == 0: self._stream = None elif hasattr(self._request, 'read'): self._stream = self._request else: self._stream = StringIO(self.raw_post_data) def _perform_form_overloading(self): """ If this is a form POST request, then we need to check if the method and content/content_type have been overridden by setting them in hidden form fields or not. """ # We only need to use form overloading on form POST requests. if (not self._USE_FORM_OVERLOADING or self._request.method != 'POST' or not is_form_media_type(self._content_type)): return # At this point we're committed to parsing the request as form data. self._data = self._request.POST self._files = self._request.FILES # Method overloading - change the method and remove the param from the content. if self._METHOD_PARAM in self._data: # NOTE: `pop` on a `QueryDict` returns a list of values. self._method = self._data.pop(self._METHOD_PARAM)[0].upper() # Content overloading - modify the content type, and re-parse. if (self._CONTENT_PARAM in self._data and self._CONTENTTYPE_PARAM in self._data): self._content_type = self._data.pop(self._CONTENTTYPE_PARAM)[0] self._stream = StringIO(self._data.pop(self._CONTENT_PARAM)[0]) self._data, self._files = self._parse() def _parse(self): """ Parse the request content, returning a two-tuple of (data, files) May raise an `UnsupportedMediaType`, or `ParseError` exception. """ if self.stream is None or self.content_type is None: return (None, None) for parser in self.get_parsers(): if parser.can_handle_request(self.content_type): parsed = parser.parse(self.stream, meta=self.META, upload_handlers=self.upload_handlers) # Parser classes may return the raw data, or a # DataAndFiles object. Unpack the result as required. try: return (parsed.data, parsed.files) except AttributeError: return (parsed, None) raise UnsupportedMediaType(self._content_type) def _authenticate(self): """ Attempt to authenticate the request using each authentication instance in turn. Returns a ``User`` object, which may be ``AnonymousUser``. """ for authentication in self.get_authentications(): user = authentication.authenticate(self) if user: return user return AnonymousUser() def __getattr__(self, name): """ Proxy other attributes to the underlying HttpRequest object. """ return getattr(self._request, name)