second commit

env/lib/python3.11/site-packages/starlette/middleware/gzip.py

@@ -0,0 +1,108 @@
+import gzip
+import io
+import typing
+
+from starlette.datastructures import Headers, MutableHeaders
+from starlette.types import ASGIApp, Message, Receive, Scope, Send
+
+
+class GZipMiddleware:
+    def __init__(self, app: ASGIApp, minimum_size: int = 500, compresslevel: int = 9) -> None:
+        self.app = app
+        self.minimum_size = minimum_size
+        self.compresslevel = compresslevel
+
+    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
+        if scope["type"] == "http":
+            headers = Headers(scope=scope)
+            if "gzip" in headers.get("Accept-Encoding", ""):
+                responder = GZipResponder(self.app, self.minimum_size, compresslevel=self.compresslevel)
+                await responder(scope, receive, send)
+                return
+        await self.app(scope, receive, send)
+
+
+class GZipResponder:
+    def __init__(self, app: ASGIApp, minimum_size: int, compresslevel: int = 9) -> None:
+        self.app = app
+        self.minimum_size = minimum_size
+        self.send: Send = unattached_send
+        self.initial_message: Message = {}
+        self.started = False
+        self.content_encoding_set = False
+        self.gzip_buffer = io.BytesIO()
+        self.gzip_file = gzip.GzipFile(mode="wb", fileobj=self.gzip_buffer, compresslevel=compresslevel)
+
+    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
+        self.send = send
+        with self.gzip_buffer, self.gzip_file:
+            await self.app(scope, receive, self.send_with_gzip)
+
+    async def send_with_gzip(self, message: Message) -> None:
+        message_type = message["type"]
+        if message_type == "http.response.start":
+            # Don't send the initial message until we've determined how to
+            # modify the outgoing headers correctly.
+            self.initial_message = message
+            headers = Headers(raw=self.initial_message["headers"])
+            self.content_encoding_set = "content-encoding" in headers
+        elif message_type == "http.response.body" and self.content_encoding_set:
+            if not self.started:
+                self.started = True
+                await self.send(self.initial_message)
+            await self.send(message)
+        elif message_type == "http.response.body" and not self.started:
+            self.started = True
+            body = message.get("body", b"")
+            more_body = message.get("more_body", False)
+            if len(body) < self.minimum_size and not more_body:
+                # Don't apply GZip to small outgoing responses.
+                await self.send(self.initial_message)
+                await self.send(message)
+            elif not more_body:
+                # Standard GZip response.
+                self.gzip_file.write(body)
+                self.gzip_file.close()
+                body = self.gzip_buffer.getvalue()
+
+                headers = MutableHeaders(raw=self.initial_message["headers"])
+                headers["Content-Encoding"] = "gzip"
+                headers["Content-Length"] = str(len(body))
+                headers.add_vary_header("Accept-Encoding")
+                message["body"] = body
+
+                await self.send(self.initial_message)
+                await self.send(message)
+            else:
+                # Initial body in streaming GZip response.
+                headers = MutableHeaders(raw=self.initial_message["headers"])
+                headers["Content-Encoding"] = "gzip"
+                headers.add_vary_header("Accept-Encoding")
+                del headers["Content-Length"]
+
+                self.gzip_file.write(body)
+                message["body"] = self.gzip_buffer.getvalue()
+                self.gzip_buffer.seek(0)
+                self.gzip_buffer.truncate()
+
+                await self.send(self.initial_message)
+                await self.send(message)
+
+        elif message_type == "http.response.body":
+            # Remaining body in streaming GZip response.
+            body = message.get("body", b"")
+            more_body = message.get("more_body", False)
+
+            self.gzip_file.write(body)
+            if not more_body:
+                self.gzip_file.close()
+
+            message["body"] = self.gzip_buffer.getvalue()
+            self.gzip_buffer.seek(0)
+            self.gzip_buffer.truncate()
+
+            await self.send(message)
+
+
+async def unattached_send(message: Message) -> typing.NoReturn:
+    raise RuntimeError("send awaitable not set")  # pragma: no cover