import cgi import codecs import logging import sys import traceback from io import BytesIO from django import http from django.conf import settings from django.core import signals from django.core.exceptions import RequestDataTooBig from django.core.handlers import base from django.http import FileResponse, HttpResponse, HttpResponseServerError from django.urls import set_script_prefix from django.utils.functional import cached_property from asgiref.sync import async_to_sync, sync_to_async from channels.exceptions import RequestAborted, RequestTimeout logger = logging.getLogger("django.request") class AsgiRequest(http.HttpRequest): """ Custom request subclass that decodes from an ASGI-standard request dict, and wraps request body handling. """ # Number of seconds until a Request gives up on trying to read a request # body and aborts. body_receive_timeout = 60 def __init__(self, scope, body): self.scope = scope self._content_length = 0 self._post_parse_error = False self._read_started = False self.resolver_match = None self.script_name = self.scope.get("root_path", "") if self.script_name and scope["path"].startswith(self.script_name): # TODO: Better is-prefix checking, slash handling? self.path_info = scope["path"][len(self.script_name) :] else: self.path_info = scope["path"] # django path is different from asgi scope path args, it should combine with script name if self.script_name: self.path = "%s/%s" % ( self.script_name.rstrip("/"), self.path_info.replace("/", "", 1), ) else: self.path = scope["path"] # HTTP basics self.method = self.scope["method"].upper() # fix https://github.com/django/channels/issues/622 query_string = self.scope.get("query_string", "") if isinstance(query_string, bytes): query_string = query_string.decode("utf-8") self.META = { "REQUEST_METHOD": self.method, "QUERY_STRING": query_string, "SCRIPT_NAME": self.script_name, "PATH_INFO": self.path_info, # Old code will need these for a while "wsgi.multithread": True, "wsgi.multiprocess": True, } if self.scope.get("client", None): self.META["REMOTE_ADDR"] = self.scope["client"][0] self.META["REMOTE_HOST"] = self.META["REMOTE_ADDR"] self.META["REMOTE_PORT"] = self.scope["client"][1] if self.scope.get("server", None): self.META["SERVER_NAME"] = self.scope["server"][0] self.META["SERVER_PORT"] = str(self.scope["server"][1]) else: self.META["SERVER_NAME"] = "unknown" self.META["SERVER_PORT"] = "0" # Handle old style-headers for a transition period if "headers" in self.scope and isinstance(self.scope["headers"], dict): self.scope["headers"] = [ (x.encode("latin1"), y) for x, y in self.scope["headers"].items() ] # Headers go into META for name, value in self.scope.get("headers", []): name = name.decode("latin1") if name == "content-length": corrected_name = "CONTENT_LENGTH" elif name == "content-type": corrected_name = "CONTENT_TYPE" else: corrected_name = "HTTP_%s" % name.upper().replace("-", "_") # HTTPbis say only ASCII chars are allowed in headers, but we latin1 just in case value = value.decode("latin1") if corrected_name in self.META: value = self.META[corrected_name] + "," + value self.META[corrected_name] = value # Pull out request encoding if we find it if "CONTENT_TYPE" in self.META: self.content_type, self.content_params = cgi.parse_header( self.META["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"] else: self.content_type, self.content_params = "", {} # Pull out content length info if self.META.get("CONTENT_LENGTH", None): try: self._content_length = int(self.META["CONTENT_LENGTH"]) except (ValueError, TypeError): pass # Body handling # TODO: chunked bodies # Limit the maximum request data size that will be handled in-memory. if ( settings.DATA_UPLOAD_MAX_MEMORY_SIZE is not None and self._content_length > settings.DATA_UPLOAD_MAX_MEMORY_SIZE ): raise RequestDataTooBig( "Request body exceeded settings.DATA_UPLOAD_MAX_MEMORY_SIZE." ) self._body = body assert isinstance(self._body, bytes), "Body is not bytes" # Add a stream-a-like for the body self._stream = BytesIO(self._body) # Other bits self.resolver_match = None @cached_property def GET(self): return http.QueryDict(self.scope.get("query_string", "")) def _get_scheme(self): return self.scope.get("scheme", "http") def _get_post(self): if not hasattr(self, "_post"): self._read_started = False self._load_post_and_files() return self._post def _set_post(self, post): self._post = post def _get_files(self): if not hasattr(self, "_files"): self._read_started = False self._load_post_and_files() return self._files POST = property(_get_post, _set_post) FILES = property(_get_files) @cached_property def COOKIES(self): return http.parse_cookie(self.META.get("HTTP_COOKIE", "")) class AsgiHandler(base.BaseHandler): """ Handler for ASGI requests for the view system only (it will have got here after traversing the dispatch-by-channel-name system, which decides it's a HTTP request) You can also manually construct it with a get_response callback if you want to run a single Django view yourself. If you do this, though, it will not do any URL routing or middleware (Channels uses it for staticfiles' serving code) """ request_class = AsgiRequest # Size to chunk response bodies into for multiple response messages chunk_size = 512 * 1024 def __init__(self, scope): if scope["type"] != "http": raise ValueError( "The AsgiHandler can only handle HTTP connections, not %s" % scope["type"] ) super(AsgiHandler, self).__init__() self.scope = scope self.load_middleware() async def __call__(self, receive, send): """ Async entrypoint - uses the sync_to_async wrapper to run things in a threadpool. """ self.send = async_to_sync(send) body = b"" while True: message = await receive() if message["type"] == "http.disconnect": # Once they disconnect, that's it. GOOD DAY SIR. I SAID GOOD. DAY. return else: # See if the message has body, and if it's the end, launch into # handling (and a synchronous subthread) if "body" in message: body += message["body"] if not message.get("more_body", False): await self.handle(body) return @sync_to_async def handle(self, body): """ Synchronous message processing. """ # Set script prefix from message root_path, turning None into empty string script_prefix = self.scope.get("root_path", "") or "" if settings.FORCE_SCRIPT_NAME: script_prefix = settings.FORCE_SCRIPT_NAME set_script_prefix(script_prefix) signals.request_started.send(sender=self.__class__, scope=self.scope) # Run request through view system try: request = self.request_class(self.scope, body) except UnicodeDecodeError: logger.warning( "Bad Request (UnicodeDecodeError)", exc_info=sys.exc_info(), extra={"status_code": 400}, ) response = http.HttpResponseBadRequest() except RequestTimeout: # Parsing the rquest failed, so the response is a Request Timeout error response = HttpResponse("408 Request Timeout (upload too slow)", status=408) except RequestAborted: # Client closed connection on us mid request. Abort! return except RequestDataTooBig: response = HttpResponse("413 Payload too large", status=413) else: response = self.get_response(request) # Fix chunk size on file responses if isinstance(response, FileResponse): response.block_size = 1024 * 512 # Transform response into messages, which we yield back to caller for response_message in self.encode_response(response): self.send(response_message) # Close the response now we're done with it response.close() def handle_uncaught_exception(self, request, resolver, exc_info): """ Last-chance handler for exceptions. """ # There's no WSGI server to catch the exception further up if this fails, # so translate it into a plain text response. try: return super(AsgiHandler, self).handle_uncaught_exception( request, resolver, exc_info ) except Exception: return HttpResponseServerError( traceback.format_exc() if settings.DEBUG else "Internal Server Error", content_type="text/plain", ) def load_middleware(self): """ Loads the Django middleware chain and caches it on the class. """ # Because we create an AsgiHandler on every HTTP request # we need to preserve the Django middleware chain once we load it. if ( hasattr(self.__class__, "_middleware_chain") and self.__class__._middleware_chain ): self._middleware_chain = self.__class__._middleware_chain self._view_middleware = self.__class__._view_middleware self._template_response_middleware = ( self.__class__._template_response_middleware ) self._exception_middleware = self.__class__._exception_middleware # Support additional arguments for Django 1.11 and 2.0. if hasattr(self.__class__, "_request_middleware"): self._request_middleware = self.__class__._request_middleware self._response_middleware = self.__class__._response_middleware else: super(AsgiHandler, self).load_middleware() self.__class__._middleware_chain = self._middleware_chain self.__class__._view_middleware = self._view_middleware self.__class__._template_response_middleware = ( self._template_response_middleware ) self.__class__._exception_middleware = self._exception_middleware # Support additional arguments for Django 1.11 and 2.0. if hasattr(self, "_request_middleware"): self.__class__._request_middleware = self._request_middleware self.__class__._response_middleware = self._response_middleware @classmethod def encode_response(cls, response): """ Encodes a Django HTTP response into ASGI http.response message(s). """ # Collect cookies into headers. # Note that we have to preserve header case as there are some non-RFC # compliant clients that want things like Content-Type correct. Ugh. response_headers = [] for header, value in response.items(): if isinstance(header, str): header = header.encode("ascii") if isinstance(value, str): value = value.encode("latin1") response_headers.append((bytes(header), bytes(value))) for c in response.cookies.values(): response_headers.append( (b"Set-Cookie", c.output(header="").encode("ascii").strip()) ) # Make initial response message yield { "type": "http.response.start", "status": response.status_code, "headers": response_headers, } # Streaming responses need to be pinned to their iterator if response.streaming: # Access `__iter__` and not `streaming_content` directly in case # it has been overridden in a subclass. for part in response: for chunk, _ in cls.chunk_bytes(part): yield { "type": "http.response.body", "body": chunk, # We ignore "more" as there may be more parts; instead, # we use an empty final closing message with False. "more_body": True, } # Final closing message yield {"type": "http.response.body"} # Other responses just need chunking else: # Yield chunks of response for chunk, last in cls.chunk_bytes(response.content): yield { "type": "http.response.body", "body": chunk, "more_body": not last, } @classmethod def chunk_bytes(cls, data): """ Chunks some data up so it can be sent in reasonable size messages. Yields (chunk, last_chunk) tuples. """ position = 0 if not data: yield data, True return while position < len(data): yield ( data[position : position + cls.chunk_size], (position + cls.chunk_size) >= len(data), ) position += cls.chunk_size