text: import asyncio
  import json
  import typing
  from collections.abc import Mapping
  from http import cookies as http_cookies
  
  from starlette.datastructures import URL, Address, FormData, Headers, QueryParams, State
  from starlette.formparsers import FormParser, MultiPartParser
  from starlette.types import Message, Receive, Scope, Send
  
  try:
      from multipart.multipart import parse_options_header
  except ImportError:  # pragma: nocover
      parse_options_header = None
  
  
  SERVER_PUSH_HEADERS_TO_COPY = {
      "accept",
      "accept-encoding",
      "accept-language",
      "cache-control",
      "user-agent",
  }
  
  
  def cookie_parser(cookie_string: str) -> typing.Dict[str, str]:
      """
      This function parses a ``Cookie`` HTTP header into a dict of key/value pairs.
  
      It attempts to mimic browser cookie parsing behavior: browsers and web servers
      frequently disregard the spec (RFC 6265) when setting and reading cookies,
      so we attempt to suit the common scenarios here.
  
      This function has been adapted from Django 3.1.0.
      Note: we are explicitly _NOT_ using `SimpleCookie.load` because it is based
      on an outdated spec and will fail on lots of input we want to support
      """
      cookie_dict: typing.Dict[str, str] = {}
      for chunk in cookie_string.split(";"):
          if "=" in chunk:
              key, val = chunk.split("=", 1)
          else:
              # Assume an empty name per
              # https://bugzilla.mozilla.org/show_bug.cgi?id=169091
              key, val = "", chunk
          key, val = key.strip(), val.strip()
          if key or val:
              # unquote using Python's algorithm.
              cookie_dict[key] = http_cookies._unquote(val)  # type: ignore
      return cookie_dict
  
  
  class ClientDisconnect(Exception):
      pass
  
  
  class HTTPConnection(Mapping):
      """
      A base class for incoming HTTP connections, that is used to provide
      any functionality that is common to both `Request` and `WebSocket`.
      """
  
      def __init__(self, scope: Scope, receive: Receive = None) -> None:
          assert scope["type"] in ("http", "websocket")
          self.scope = scope
  
      def __getitem__(self, key: str) -> str:
          return self.scope[key]
  
      def __iter__(self) -> typing.Iterator[str]:
          return iter(self.scope)
  
      def __len__(self) -> int:
          return len(self.scope)
  
      @property
      def app(self) -> typing.Any:
          return self.scope["app"]
  
      @property
      def url(self) -> URL:
          if not hasattr(self, "_url"):
              self._url = URL(scope=self.scope)
          return self._url
  
      @property
      def base_url(self) -> URL:
          if not hasattr(self, "_base_url"):
              base_url_scope = dict(self.scope)
              base_url_scope["path"] = "/"
              base_url_scope["query_string"] = b""
              base_url_scope["root_path"] = base_url_scope.get(
                  "app_root_path", base_url_scope.get("root_path", "")
              )
              self._base_url = URL(scope=base_url_scope)
          return self._base_url
  
      @property
      def headers(self) -> Headers:
          if not hasattr(self, "_headers"):
              self._headers = Headers(scope=self.scope)
          return self._headers
  
      @property
      def query_params(self) -> QueryParams:
          if not hasattr(self, "_query_params"):
              self._query_params = QueryParams(self.scope["query_string"])
          return self._query_params
  
      @property
      def path_params(self) -> dict:
          return self.scope.get("path_params", {})
  
      @property
      def cookies(self) -> typing.Dict[str, str]:
          if not hasattr(self, "_cookies"):
              cookies: typing.Dict[str, str] = {}
              cookie_header = self.headers.get("cookie")
  
              if cookie_header:
                  cookies = cookie_parser(cookie_header)
              self._cookies = cookies
          return self._cookies
  
      @property
      def client(self) -> Address:
          host, port = self.scope.get("client") or (None, None)
          return Address(host=host, port=port)
  
      @property
      def session(self) -> dict:
          assert (
              "session" in self.scope
          ), "SessionMiddleware must be installed to access request.session"
          return self.scope["session"]
  
      @property
      def auth(self) -> typing.Any:
          assert (
              "auth" in self.scope
          ), "AuthenticationMiddleware must be installed to access request.auth"
          return self.scope["auth"]
  
      @property
      def user(self) -> typing.Any:
          assert (
              "user" in self.scope
          ), "AuthenticationMiddleware must be installed to access request.user"
          return self.scope["user"]
  
      @property
      def state(self) -> State:
          if not hasattr(self, "_state"):
              # Ensure 'state' has an empty dict if it's not already populated.
              self.scope.setdefault("state", {})
              # Create a state instance with a reference to the dict in which it should store info
              self._state = State(self.scope["state"])
          return self._state
  
      def url_for(self, name: str, **path_params: typing.Any) -> str:
          router = self.scope["router"]
          url_path = router.url_path_for(name, **path_params)
          return url_path.make_absolute_url(base_url=self.base_url)
  
  
  async def empty_receive() -> Message:
      raise RuntimeError("Receive channel has not been made available")
  
  
  async def empty_send(message: Message) -> None:
      raise RuntimeError("Send channel has not been made available")
  
  
  class Request(HTTPConnection):
      def __init__(
          self, scope: Scope, receive: Receive = empty_receive, send: Send = empty_send
      ):
          super().__init__(scope)
          assert scope["type"] == "http"
          self._receive = receive
          self._send = send
          self._stream_consumed = False
          self._is_disconnected = False
  
      @property
      def method(self) -> str:
          return self.scope["method"]
  
      @property
      def receive(self) -> Receive:
          return self._receive
  
      async def stream(self) -> typing.AsyncGenerator[bytes, None]:
          if hasattr(self, "_body"):
              yield self._body
              yield b""
              return
  
          if self._stream_consumed:
              raise RuntimeError("Stream consumed")
  
          self._stream_consumed = True
          while True:
              message = await self._receive()
              if message["type"] == "http.request":
                  body = message.get("body", b"")
                  if body:
                      yield body
                  if not message.get("more_body", False):
                      break
              elif message["type"] == "http.disconnect":
                  self._is_disconnected = True
                  raise ClientDisconnect()
          yield b""
  
      async def body(self) -> bytes:
          if not hasattr(self, "_body"):
              chunks = []
              async for chunk in self.stream():
                  chunks.append(chunk)
              self._body = b"".join(chunks)
          return self._body
  
      async def json(self) -> typing.Any:
          if not hasattr(self, "_json"):
              body = await self.body()
              self._json = json.loads(body)
          return self._json
  
      async def form(self) -> FormData:
          if not hasattr(self, "_form"):
              assert (
                  parse_options_header is not None
              ), "The `python-multipart` library must be installed to use form parsing."
              content_type_header = self.headers.get("Content-Type")
              content_type, options = parse_options_header(content_type_header)
              if content_type == b"multipart/form-data":
                  multipart_parser = MultiPartParser(self.headers, self.stream())
                  self._form = await multipart_parser.parse()
              elif content_type == b"application/x-www-form-urlencoded":
                  form_parser = FormParser(self.headers, self.stream())
                  self._form = await form_parser.parse()
              else:
                  self._form = FormData()
          return self._form
  
      async def close(self) -> None:
          if hasattr(self, "_form"):
              await self._form.close()
  
      async def is_disconnected(self) -> bool:
          if not self._is_disconnected:
              try:
                  message = await asyncio.wait_for(self._receive(), timeout=0.0000001)
              except asyncio.TimeoutError:
                  message = {}
  
              if message.get("type") == "http.disconnect":
                  self._is_disconnected = True
  
          return self._is_disconnected
  
      async def send_push_promise(self, path: str) -> None:
          if "http.response.push" in self.scope.get("extensions", {}):
              raw_headers = []
              for name in SERVER_PUSH_HEADERS_TO_COPY:
                  for value in self.headers.getlist(name):
                      raw_headers.append(
                          (name.encode("latin-1"), value.encode("latin-1"))
                      )
              await self._send(
                  {"type": "http.response.push", "path": path, "headers": raw_headers}
              )
  