flask 源码解析：请求

from flask import requestwith app.request_context(environ):assert request.method == 'POST'

from werkzeug.wrappers import Request as RequestBaseclass Request(RequestBase):"""The request object is a :class:`~werkzeug.wrappers.Request` subclass andprovides all of the attributes Werkzeug defines plus a few Flaskspecific ones."""#: The internal URL rule that matched the request.  This can be#: useful to inspect which methods are allowed for the URL from#: a before/after handler (``request.url_rule.methods``) etc.url_rule = None#: A dict of view arguments that matched the request.  If an exception#: happened when matching, this will be ``None``.view_args = None    @propertydef max_content_length(self):"""Read-only view of the ``MAX_CONTENT_LENGTH`` config key."""ctx = _request_ctx_stack.topif ctx is not None:return ctx.app.config['MAX_CONTENT_LENGTH']    @propertydef endpoint(self):"""The endpoint that matched the request.  This in combination with:attr:`view_args` can be used to reconstruct the same or amodified URL.  If an exception happened when matching, this willbe ``None``."""if self.url_rule is not None:return self.url_rule.endpoint    @propertydef blueprint(self):"""The name of the current blueprint"""if self.url_rule and '.' in self.url_rule.endpoint:return self.url_rule.endpoint.rsplit('.', 1)[0]    @propertydef is_json(self):mt = self.mimetypeif mt == 'application/json':return Trueif mt.startswith('application/') and mt.endswith('+json'):return Truereturn False

class Request(BaseRequest, AcceptMixin, ETagRequestMixin,UserAgentMixin, AuthorizationMixin,CommonRequestDescriptorsMixin):"""Full featured request object implementing the following mixins:- :class:`AcceptMixin` for accept header parsing- :class:`ETagRequestMixin` for etag and cache control handling- :class:`UserAgentMixin` for user agent introspection- :class:`AuthorizationMixin` for http auth handling- :class:`CommonRequestDescriptorsMixin` for common headers"""

class Request(BaseRequest, AcceptMixin)pass

class BaseRequest(object):def __init__(self, environ, populate_request=True, shallow=False):self.environ = environif populate_request and not shallow:self.environ['werkzeug.request'] = selfself.shallow = shallow

    @cached_propertydef args(self):"""The parsed URL parameters."""return url_decode(wsgi_get_bytes(self.environ.get('QUERY_STRING', '')),self.url_charset, errors=self.encoding_errors,cls=self.parameter_storage_class)    @cached_propertydef stream(self):"""The stream to read incoming data from.  Unlike :attr:`input_stream`this stream is properly guarded that you can't accidentally read pastthe length of the input.  Werkzeug will internally always refer tothis stream to read data which makes it possible to wrap thisobject with a stream that does filtering."""_assert_not_shallow(self)return get_input_stream(self.environ)    @cached_propertydef form(self):"""The form parameters."""self._load_form_data()return self.form    @cached_propertydef cookies(self):"""Read only access to the retrieved cookie values as dictionary."""return parse_cookie(self.environ, self.charset,self.encoding_errors,cls=self.dict_storage_class)    @cached_propertydef headers(self):"""The headers from the WSGI environ as immutable:class:`~werkzeug.datastructures.EnvironHeaders`."""return EnvironHeaders(self.environ)

class cached_property(property):"""A decorator that converts a function into a lazy property.  Thefunction wrapped is called the first time to retrieve the resultand then that calculated result is used the next time you accessthe value.The class has to have a `__dict__` in order for this property towork."""# implementation detail: A subclass of python's builtin property# decorator, we override __get__ to check for a cached value. If one# choses to invoke __get__ by hand the property will still work as# expected because the lookup logic is replicated in __get__ for# manual invocation.def __init__(self, func, name=None, doc=None):self.__name__ = name or func.__name__self.__module__ = func.__module__self.__doc__ = doc or func.__doc__self.func = funcdef __set__(self, obj, value):obj.__dict__[self.__name__] = valuedef __get__(self, obj, type=None):if obj is None:return selfvalue = obj.__dict__.get(self.__name__, _missing)if value is _missing:value = self.func(obj)obj.__dict__[self.__name__] = valuereturn value

class AcceptMixin(object):    @cached_propertydef accept_mimetypes(self):return parse_accept_header(self.environ.get('HTTP_ACCEPT'), MIMEAccept)    @cached_propertydef accept_charsets(self):return parse_accept_header(self.environ.get('HTTP_ACCEPT_CHARSET'),CharsetAccept)    @cached_propertydef accept_encodings(self):return parse_accept_header(self.environ.get('HTTP_ACCEPT_ENCODING'))    @cached_propertydef accept_languages(self):return parse_accept_header(self.environ.get('HTTP_ACCEPT_LANGUAGE'),LanguageAccept)