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.venv/lib/python3.9/site-packages/starlette/middleware/wsgi.py

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+import asyncio
+import io
+import sys
+import typing
+
+from starlette.concurrency import run_in_threadpool
+from starlette.types import Message, Receive, Scope, Send
+
+
+def build_environ(scope: Scope, body: bytes) -> dict:
+    """
+    Builds a scope and request body into a WSGI environ object.
+    """
+    environ = {
+        "REQUEST_METHOD": scope["method"],
+        "SCRIPT_NAME": scope.get("root_path", "").encode("utf8").decode("latin1"),
+        "PATH_INFO": scope["path"].encode("utf8").decode("latin1"),
+        "QUERY_STRING": scope["query_string"].decode("ascii"),
+        "SERVER_PROTOCOL": f"HTTP/{scope['http_version']}",
+        "wsgi.version": (1, 0),
+        "wsgi.url_scheme": scope.get("scheme", "http"),
+        "wsgi.input": io.BytesIO(body),
+        "wsgi.errors": sys.stdout,
+        "wsgi.multithread": True,
+        "wsgi.multiprocess": True,
+        "wsgi.run_once": False,
+    }
+
+    # Get server name and port - required in WSGI, not in ASGI
+    server = scope.get("server") or ("localhost", 80)
+    environ["SERVER_NAME"] = server[0]
+    environ["SERVER_PORT"] = server[1]
+
+    # Get client IP address
+    if scope.get("client"):
+        environ["REMOTE_ADDR"] = scope["client"][0]
+
+    # Go through headers and make them into environ entries
+    for name, value in 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 = f"HTTP_{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 environ:
+            value = environ[corrected_name] + "," + value
+        environ[corrected_name] = value
+    return environ
+
+
+class WSGIMiddleware:
+    def __init__(self, app: typing.Callable, workers: int = 10) -> None:
+        self.app = app
+
+    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
+        assert scope["type"] == "http"
+        responder = WSGIResponder(self.app, scope)
+        await responder(receive, send)
+
+
+class WSGIResponder:
+    def __init__(self, app: typing.Callable, scope: Scope) -> None:
+        self.app = app
+        self.scope = scope
+        self.status = None
+        self.response_headers = None
+        self.send_event = asyncio.Event()
+        self.send_queue = []  # type: typing.List[typing.Optional[Message]]
+        self.loop = asyncio.get_event_loop()
+        self.response_started = False
+        self.exc_info = None  # type: typing.Any
+
+    async def __call__(self, receive: Receive, send: Send) -> None:
+        body = b""
+        more_body = True
+        while more_body:
+            message = await receive()
+            body += message.get("body", b"")
+            more_body = message.get("more_body", False)
+        environ = build_environ(self.scope, body)
+        sender = None
+        try:
+            sender = self.loop.create_task(self.sender(send))
+            await run_in_threadpool(self.wsgi, environ, self.start_response)
+            self.send_queue.append(None)
+            self.send_event.set()
+            await asyncio.wait_for(sender, None)
+            if self.exc_info is not None:
+                raise self.exc_info[0].with_traceback(
+                    self.exc_info[1], self.exc_info[2]
+                )
+        finally:
+            if sender and not sender.done():
+                sender.cancel()  # pragma: no cover
+
+    async def sender(self, send: Send) -> None:
+        while True:
+            if self.send_queue:
+                message = self.send_queue.pop(0)
+                if message is None:
+                    return
+                await send(message)
+            else:
+                await self.send_event.wait()
+                self.send_event.clear()
+
+    def start_response(
+        self,
+        status: str,
+        response_headers: typing.List[typing.Tuple[str, str]],
+        exc_info: typing.Any = None,
+    ) -> None:
+        self.exc_info = exc_info
+        if not self.response_started:
+            self.response_started = True
+            status_code_string, _ = status.split(" ", 1)
+            status_code = int(status_code_string)
+            headers = [
+                (name.strip().encode("ascii").lower(), value.strip().encode("ascii"))
+                for name, value in response_headers
+            ]
+            self.send_queue.append(
+                {
+                    "type": "http.response.start",
+                    "status": status_code,
+                    "headers": headers,
+                }
+            )
+            self.loop.call_soon_threadsafe(self.send_event.set)
+
+    def wsgi(self, environ: dict, start_response: typing.Callable) -> None:
+        for chunk in self.app(environ, start_response):
+            self.send_queue.append(
+                {"type": "http.response.body", "body": chunk, "more_body": True}
+            )
+            self.loop.call_soon_threadsafe(self.send_event.set)
+
+        self.send_queue.append({"type": "http.response.body", "body": b""})
+        self.loop.call_soon_threadsafe(self.send_event.set)