Django_WSGIRequest对象
WSGIRequest对象
Django在接收到http请求之后，会根据http请求携带的参数以及报文信息创建一个WSGIRequest对象，并且作为视图函数第一个参数传给视图函数。这个参数就是django视图函数的第一个参数，通常写成request。在这个对象上我们可以找到客户端上传上来的所有信息。这个对象的完整路径是django.core.handlers.wsgi.WSGIRequest。
class WSGIRequest(HttpRequest): def __init__(self, environ): script_name = get_script_name(environ) path_info = get_path_info(environ) if not path_info: # Sometimes PATH_INFO exists, but is empty (e.g. accessing # the SCRIPT_NAME URL without a trailing slash). We really need to # operate as if they'd requested '/'. Not amazingly nice to force # the path like this, but should be harmless. path_info = '/' self.environ = environ self.path_info = path_info # be careful to only replace the first slash in the path because of # http://test/something and http://test//something being different as # stated in http://www.ietf.org/rfc/rfc2396.txt self.path = '%s/%s' % (script_name.rstrip('/'), path_info.replace('/', '', 1)) self.META = environ self.META['PATH_INFO'] = path_info self.META['SCRIPT_NAME'] = script_name self.method = environ['REQUEST_METHOD'].upper() self.content_type, self.content_params = cgi.parse_header(environ.get('CONTENT_TYPE', '')) if 'charset' in self.content_params: try: codecs.lookup(self.content_params['charset']) except LookupError: pass else: self.encoding = self.content_params['charset'] self._post_parse_error = False try: content_length = int(environ.get('CONTENT_LENGTH')) except (ValueError, TypeError): content_length = 0 self._stream = LimitedStream(self.environ['wsgi.input'], content_length) self._read_started = False self.resolver_match = None def _get_scheme(self): return self.environ.get('wsgi.url_scheme') @cached_property def GET(self): # The WSGI spec says 'QUERY_STRING' may be absent. raw_query_string = get_bytes_from_wsgi(self.environ, 'QUERY_STRING', '') return QueryDict(raw_query_string, encoding=self._encoding) def _get_post(self): if not hasattr(self, '_post'): self._load_post_and_files() return self._post def _set_post(self, post): self._post = post @cached_property def COOKIES(self): raw_cookie = get_str_from_wsgi(self.environ, 'HTTP_COOKIE', '') return parse_cookie(raw_cookie) @property def FILES(self): if not hasattr(self, '_files'): self._load_post_and_files() return self._files POST = property(_get_post, _set_post) class HttpRequest: """A basic HTTP request.""" # The encoding used in GET/POST dicts. None means use default setting. _encoding = None _upload_handlers = [] def __init__(self): # WARNING: The `WSGIRequest` subclass doesn't call `super`. # Any variable assignment made here should also happen in # `WSGIRequest.__init__()`. self.GET = QueryDict(mutable=True) self.POST = QueryDict(mutable=True) self.COOKIES = {} self.META = {} self.FILES = MultiValueDict() self.path = '' self.path_info = '' self.method = None self.resolver_match = None self._post_parse_error = False self.content_type = None self.content_params = None def __repr__(self): if self.method is None or not self.get_full_path(): return '<%s>' % self.__class__.__name__ return '<%s: %s %r>' % (self.__class__.__name__, self.method, self.get_full_path()) def _get_raw_host(self): """ Return the HTTP host using the environment or request headers. Skip allowed hosts protection, so may return an insecure host. """ # We try three options, in order of decreasing preference. if settings.USE_X_FORWARDED_HOST and ( 'HTTP_X_FORWARDED_HOST' in self.META): host = self.META['HTTP_X_FORWARDED_HOST'] elif 'HTTP_HOST' in self.META: host = self.META['HTTP_HOST'] else: # Reconstruct the host using the algorithm from PEP 333. host = self.META['SERVER_NAME'] server_port = self.get_port() if server_port != ('443' if self.is_secure() else '80'): host = '%s:%s' % (host, server_port) return host def get_host(self): """Return the HTTP host using the environment or request headers.""" host = self._get_raw_host() # Allow variants of localhost if ALLOWED_HOSTS is empty and DEBUG=True. allowed_hosts = settings.ALLOWED_HOSTS if settings.DEBUG and not allowed_hosts: allowed_hosts = ['localhost', '127.0.0.1', '[::1]'] domain, port = split_domain_port(host) if domain and validate_host(domain, allowed_hosts): return host else: msg = "Invalid HTTP_HOST header: %r." % host if domain: msg += " You may need to add %r to ALLOWED_HOSTS." % domain else: msg += " The domain name provided is not valid according to RFC 1034/1035." raise DisallowedHost(msg) def get_port(self): """Return the port number for the request as a string.""" if settings.USE_X_FORWARDED_PORT and 'HTTP_X_FORWARDED_PORT' in self.META: port = self.META['HTTP_X_FORWARDED_PORT'] else: port = self.META['SERVER_PORT'] return str(port) def get_full_path(self, force_append_slash=False): # RFC 3986 requires query string arguments to be in the ASCII range. # Rather than crash if this doesn't happen, we encode defensively. return '%s%s%s' % ( escape_uri_path(self.path), '/' if force_append_slash and not self.path.endswith('/') else '', ('?' + iri_to_uri(self.META.get('QUERY_STRING', ''))) if self.META.get('QUERY_STRING', '') else '' ) def get_signed_cookie(self, key, default=RAISE_ERROR, salt='', max_age=None): """ Attempt to return a signed cookie. If the signature fails or the cookie has expired, raise an exception, unless the `default` argument is provided, in which case return that value. """ try: cookie_value = self.COOKIES[key] except KeyError: if default is not RAISE_ERROR: return default else: raise try: value = signing.get_cookie_signer(salt=key + salt).unsign( cookie_value, max_age=max_age) except signing.BadSignature: if default is not RAISE_ERROR: return default else: raise return value def get_raw_uri(self): """ Return an absolute URI from variables available in this request. Skip allowed hosts protection, so may return insecure URI. """ return '{scheme}://{host}{path}'.format( scheme=self.scheme, host=self._get_raw_host(), path=self.get_full_path(), ) def build_absolute_uri(self, location=None): """ Build an absolute URI from the location and the variables available in this request. If no ``location`` is specified, bulid the absolute URI using request.get_full_path(). If the location is absolute, convert it to an RFC 3987 compliant URI and return it. If location is relative or is scheme-relative (i.e., ``//example.com/``), urljoin() it to a base URL constructed from the request variables. """ if location is None: # Make it an absolute url (but schemeless and domainless) for the # edge case that the path starts with '//'. location = '//%s' % self.get_full_path() bits = urlsplit(location) if not (bits.scheme and bits.netloc): current_uri = '{scheme}://{host}{path}'.format(scheme=self.scheme, host=self.get_host(), path=self.path) # Join the constructed URL with the provided location, which will # allow the provided ``location`` to apply query strings to the # base path as well as override the host, if it begins with // location = urljoin(current_uri, location) return iri_to_uri(location) def _get_scheme(self): """ Hook for subclasses like WSGIRequest to implement. Return 'http' by default. """ return 'http' @property def scheme(self): if settings.SECURE_PROXY_SSL_HEADER: try: header, value = settings.SECURE_PROXY_SSL_HEADER except ValueError: raise ImproperlyConfigured( 'The SECURE_PROXY_SSL_HEADER setting must be a tuple containing two values.' ) if self.META.get(header) == value: return 'https' return self._get_scheme() def is_secure(self): return self.scheme == 'https' def is_ajax(self): return self.META.get('HTTP_X_REQUESTED_WITH') == 'XMLHttpRequest' @property def encoding(self): return self._encoding @encoding.setter def encoding(self, val): """ Set the encoding used for GET/POST accesses. If the GET or POST dictionary has already been created, remove and recreate it on the next access (so that it is decoded correctly). """ self._encoding = val if hasattr(self, 'GET'): del self.GET if hasattr(self, '_post'): del self._post def _initialize_handlers(self): self._upload_handlers = [uploadhandler.load_handler(handler, self) for handler in settings.FILE_UPLOAD_HANDLERS] @property def upload_handlers(self): if not self._upload_handlers: # If there are no upload handlers defined, initialize them from settings. self._initialize_handlers() return self._upload_handlers @upload_handlers.setter def upload_handlers(self, upload_handlers): if hasattr(self, '_files'): raise AttributeError("You cannot set the upload handlers after the upload has been processed.") self._upload_handlers = upload_handlers def parse_file_upload(self, META, post_data): """Return a tuple of (POST QueryDict, FILES MultiValueDict).""" self.upload_handlers = ImmutableList( self.upload_handlers, warning="You cannot alter upload handlers after the upload has been processed." ) parser = MultiPartParser(META, post_data, self.upload_handlers, self.encoding) return parser.parse() @property def body(self): if not hasattr(self, '_body'): if self._read_started: raise RawPostDataException("You cannot access body after reading from request's data stream") # Limit the maximum request data size that will be handled in-memory. if (settings.DATA_UPLOAD_MAX_MEMORY_SIZE is not None and int(self.META.get('CONTENT_LENGTH') or 0) > settings.DATA_UPLOAD_MAX_MEMORY_SIZE): raise RequestDataTooBig('Request body exceeded settings.DATA_UPLOAD_MAX_MEMORY_SIZE.') try: self._body = self.read() except IOError as e: raise UnreadablePostError(*e.args) from e self._stream = BytesIO(self._body) return self._body def _mark_post_parse_error(self): self._post = QueryDict() self._files = MultiValueDict() self._post_parse_error = True def _load_post_and_files(self): """Populate self._post and self._files if the content-type is a form type""" if self.method != 'POST': self._post, self._files = QueryDict(encoding=self._encoding), MultiValueDict() return if self._read_started and not hasattr(self, '_body'): self._mark_post_parse_error() return if self.content_type == 'multipart/form-data': if hasattr(self, '_body'): # Use already read data data = BytesIO(self._body) else: data = self try: self._post, self._files = self.parse_file_upload(self.META, data) except MultiPartParserError: # An error occurred while parsing POST data. Since when # formatting the error the request handler might access # self.POST, set self._post and self._file to prevent # attempts to parse POST data again. # Mark that an error occurred. This allows self.__repr__ to # be explicit about it instead of simply representing an # empty POST self._mark_post_parse_error() raise elif self.content_type == 'application/x-www-form-urlencoded': self._post, self._files = QueryDict(self.body, encoding=self._encoding), MultiValueDict() else: self._post, self._files = QueryDict(encoding=self._encoding), MultiValueDict() def close(self): if hasattr(self, '_files'): for f in chain.from_iterable(l[1] for l in self._files.lists()): f.close() # File-like and iterator interface. # # Expects self._stream to be set to an appropriate source of bytes by # a corresponding request subclass (e.g. WSGIRequest). # Also when request data has already been read by request.POST or # request.body, self._stream points to a BytesIO instance # containing that data. def read(self, *args, **kwargs): self._read_started = True try: return self._stream.read(*args, **kwargs) except IOError as e: raise UnreadablePostError(*e.args) from e def readline(self, *args, **kwargs): self._read_started = True try: return self._stream.readline(*args, **kwargs) except IOError as e: raise UnreadablePostError(*e.args) from e def __iter__(self): while True: buf = self.readline() if not buf: break yield buf def xreadlines(self): warnings.warn( 'HttpRequest.xreadlines() is deprecated in favor of iterating the ' 'request.', RemovedInDjango30Warning, stacklevel=2, ) yield from self def readlines(self): return list(self)
http请求的url详解：
在了解WSGIRequest对象的属性和方法之前，我们先了解一下url的组成，通常来说url的完整组成如下，[]为可选：
protocol ://hostname[:port]/path/[;parameters][?query]#fragment
- protocol： 网络协议，常用的协议有http/https/ftp等
- hostname： 主机地址，可以是域名，也可以是IP地址
- port： 端口 http协议默认端口是：80端口，在浏览器中默认会隐藏不显示
- path：路径 网络资源在服务器中的指定路径
- parameter： 参数 如果要向服务器传入参数，在这部分输入
- query： 查询字符串 如果需要从服务器那里查询内容，在这里编辑
- fragment：片段 网页中可能会分为不同的片段，如果想访问网页后直接到达指定位置，可以在这部分设置
WSGIRequest对象常用属性：
WSGIRequest对象上大部分的属性都是只读的。因为这些属性是从客户端上传上来的，没必要做任何的修改，在django视图中使用时，视图函数的第一个参数参数request就是WSGIRequest对象。以下将对一些常用的属性进行讲解：
path：资源在服务器的完整“路径”，但不包含域名和参数，在url中也是path的内容。比如http://www.baidu.com/xxx/yyy/，那么path就是/xxx/yyy/。method：代表当前请求的http方法。比如是GET、POST、delete或者是put等方法GET：一个django.http.request.QueryDict对象。操作起来类似于字典。这个属性中包含了所有以?xxx=xxx的方式上传上来的参数。POST：也是一个django.http.request.QueryDict对象。这个属性中包含了所有以POST方式上传上来的参数。FILES：也是一个django.http.request.QueryDict对象。这个属性中包含了所有上传的文件。COOKIES：一个标准的Python字典，包含所有的cookie，键值对都是字符串类型。session：一个类似于字典的对象。用来操作服务器的session。-
user：user 只有当Django 启用 AuthenticationMiddleware 中间件时才可用。它的值是一个 setting.py 里面AUTH_USER_MODEL 字段所定义的类的对象，表示当前登录的用户。如果用户当前没有登录，user 将设为 django.contrib.auth.models.AnonymousUser 的一个实例。你可以通过 is_authenticated() 区分它们。
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META：存储的客户端发送上来的所有header信息，下面是这些常用的header信息：-
CONTENT_LENGTH：请求的正文的长度（是一个字符串）。 CONTENT_TYPE：请求的正文的MIME类型。HTTP_ACCEPT：响应可接收的Content-Type。HTTP_ACCEPT_ENCODING：响应可接收的编码，用于告知服务器客户端所能够处理的编码方式和相对优先级。HTTP_ACCEPT_LANGUAGE： 响应可接收的语言。HTTP_HOST：客户端发送的HOST值。HTTP_REFERER：在访问这个页面上一个页面的url。QUERY_STRING：单个字符串形式的查询字符串（未解析过的形式）。- TE：设置传输实体的编码格式，表示请求发起者愿意接收的Transfer-Encoding类型(传输过程中的编码格式，代理服务器之间)
REMOTE_ADDR：客户端的IP地址。如果服务器使用了nginx做反向代理或者负载均衡，那么这个值返回的是127.0.0.1，这时候可以使用HTTP_X_FORWARDED_FOR来获取，所以获取ip地址的代码片段如下：if request.META.has_key('HTTP_X_FORWARDED_FOR'): ip = request.META['HTTP_X_FORWARDED_FOR'] else: ip = request.META['REMOTE_ADDR']REMOTE_HOST：客户端的主机名。REQUEST_METHOD：请求方法。一个字符串类似于GET或者POST。SERVER_NAME：服务器域名。SERVER_PORT：服务器端口号，是一个字符串类型。
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WSGIRequest对象常用方法：
is_secure()：是否是采用https协议。is_ajax()：是否采用ajax发送的请求。原理就是判断请求头中是否存在X-Requested-With:XMLHttpRequest。get_host()：服务器的域名。如果在访问的时候还有端口号，那么会加上端口号，在url中就是hostname+port。比如www.baidu.com:9000。get_full_path()：返回完整的path。如果有查询字符串，还会加上查询字符串，在url中就是path以及其后面的所有。比如/music/bands/?print=True。get_raw_uri()：获取请求的完整url。
QueryDict对象：
用法：https://www.cnblogs.com/fat39/p/9646971.html
我们平时用的request.GET、request.POST和request.FILES都是QueryDict对象，这个对象继承自dict，因此用法跟dict相差无几。其中用得比较多的是get方法和getlist方法。
get方法：用来获取指定key的值，如果没有这个key，那么会返回None。getlist方法：如果浏览器上传上来的key对应的值有多个，如果使用get取值，那么你只能取出最后面一个值，如果你想取到所有的值，那么就需要通过getlist这个方法获取。
