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stbi/Lib/site-packages/asgiref/wsgi.py

+from io import BytesIO
+from tempfile import SpooledTemporaryFile
+
+from asgiref.sync import AsyncToSync, sync_to_async
+
+
+class WsgiToAsgi:
+    """
+    Wraps a WSGI application to make it into an ASGI application.
+    """
+
+    def __init__(self, wsgi_application):
+        self.wsgi_application = wsgi_application
+
+    async def __call__(self, scope, receive, send):
+        """
+        ASGI application instantiation point.
+        We return a new WsgiToAsgiInstance here with the WSGI app
+        and the scope, ready to respond when it is __call__ed.
+        """
+        await WsgiToAsgiInstance(self.wsgi_application)(scope, receive, send)
+
+
+class WsgiToAsgiInstance:
+    """
+    Per-socket instance of a wrapped WSGI application
+    """
+
+    def __init__(self, wsgi_application):
+        self.wsgi_application = wsgi_application
+        self.response_started = False
+
+    async def __call__(self, scope, receive, send):
+        if scope["type"] != "http":
+            raise ValueError("WSGI wrapper received a non-HTTP scope")
+        self.scope = scope
+        with SpooledTemporaryFile(max_size=65536) as body:
+            # Alright, wait for the http.request messages
+            while True:
+                message = await receive()
+                if message["type"] != "http.request":
+                    raise ValueError("WSGI wrapper received a non-HTTP-request message")
+                body.write(message.get("body", b""))
+                if not message.get("more_body"):
+                    break
+            body.seek(0)
+            # Wrap send so it can be called from the subthread
+            self.sync_send = AsyncToSync(send)
+            # Call the WSGI app
+            await self.run_wsgi_app(body)
+
+    def build_environ(self, scope, body):
+        """
+        Builds a scope and request body into a WSGI environ object.
+        """
+        environ = {
+            "REQUEST_METHOD": scope["method"],
+            "SCRIPT_NAME": scope.get("root_path", ""),
+            "PATH_INFO": scope["path"],
+            "QUERY_STRING": scope["query_string"].decode("ascii"),
+            "SERVER_PROTOCOL": "HTTP/%s" % scope["http_version"],
+            "wsgi.version": (1, 0),
+            "wsgi.url_scheme": scope.get("scheme", "http"),
+            "wsgi.input": body,
+            "wsgi.errors": BytesIO(),
+            "wsgi.multithread": True,
+            "wsgi.multiprocess": True,
+            "wsgi.run_once": False,
+        }
+        # Get server name and port - required in WSGI, not in ASGI
+        if "server" in scope:
+            environ["SERVER_NAME"] = scope["server"][0]
+            environ["SERVER_PORT"] = str(scope["server"][1])
+        else:
+            environ["SERVER_NAME"] = "localhost"
+            environ["SERVER_PORT"] = "80"
+
+        if "client" in scope:
+            environ["REMOTE_ADDR"] = scope["client"][0]
+
+        # Go through headers and make them into environ entries
+        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 environ:
+                value = environ[corrected_name] + "," + value
+            environ[corrected_name] = value
+        return environ
+
+    def start_response(self, status, response_headers, exc_info=None):
+        """
+        WSGI start_response callable.
+        """
+        # Don't allow re-calling once response has begun
+        if self.response_started:
+            raise exc_info[1].with_traceback(exc_info[2])
+        # Don't allow re-calling without exc_info
+        if hasattr(self, "response_start") and exc_info is None:
+            raise ValueError(
+                "You cannot call start_response a second time without exc_info"
+            )
+        # Extract status code
+        status_code, _ = status.split(" ", 1)
+        status_code = int(status_code)
+        # Extract headers
+        headers = [
+            (name.lower().encode("ascii"), value.encode("ascii"))
+            for name, value in response_headers
+        ]
+        # Build and send response start message.
+        self.response_start = {
+            "type": "http.response.start",
+            "status": status_code,
+            "headers": headers,
+        }
+
+    @sync_to_async
+    def run_wsgi_app(self, body):
+        """
+        Called in a subthread to run the WSGI app. We encapsulate like
+        this so that the start_response callable is called in the same thread.
+        """
+        # Translate the scope and incoming request body into a WSGI environ
+        environ = self.build_environ(self.scope, body)
+        # Run the WSGI app
+        for output in self.wsgi_application(environ, self.start_response):
+            # If this is the first response, include the response headers
+            if not self.response_started:
+                self.response_started = True
+                self.sync_send(self.response_start)
+            self.sync_send(
+                {"type": "http.response.body", "body": output, "more_body": True}
+            )
+        # Close connection
+        if not self.response_started:
+            self.response_started = True
+            self.sync_send(self.response_start)
+        self.sync_send({"type": "http.response.body"})