Update 2025-04-13_16:26:34

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

@@ -0,0 +1,141 @@
+import gzip
+import io
+import typing
+
+from starlette.datastructures import Headers, MutableHeaders
+from starlette.types import ASGIApp, Message, Receive, Scope, Send
+
+DEFAULT_EXCLUDED_CONTENT_TYPES = ("text/event-stream",)
+
+
+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":  # pragma: no cover
+            await self.app(scope, receive, send)
+            return
+
+        headers = Headers(scope=scope)
+        responder: ASGIApp
+        if "gzip" in headers.get("Accept-Encoding", ""):
+            responder = GZipResponder(self.app, self.minimum_size, compresslevel=self.compresslevel)
+        else:
+            responder = IdentityResponder(self.app, self.minimum_size)
+
+        await responder(scope, receive, send)
+
+
+class IdentityResponder:
+    content_encoding: str
+
+    def __init__(self, app: ASGIApp, minimum_size: int) -> 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.content_type_is_excluded = False
+
+    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
+        self.send = send
+        await self.app(scope, receive, self.send_with_compression)
+
+    async def send_with_compression(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
+            self.content_type_is_excluded = headers.get("content-type", "").startswith(DEFAULT_EXCLUDED_CONTENT_TYPES)
+        elif message_type == "http.response.body" and (self.content_encoding_set or self.content_type_is_excluded):
+            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 compression to small outgoing responses.
+                await self.send(self.initial_message)
+                await self.send(message)
+            elif not more_body:
+                # Standard response.
+                body = self.apply_compression(body, more_body=False)
+
+                headers = MutableHeaders(raw=self.initial_message["headers"])
+                headers.add_vary_header("Accept-Encoding")
+                if body != message["body"]:
+                    headers["Content-Encoding"] = self.content_encoding
+                    headers["Content-Length"] = str(len(body))
+                    message["body"] = body
+
+                await self.send(self.initial_message)
+                await self.send(message)
+            else:
+                # Initial body in streaming response.
+                body = self.apply_compression(body, more_body=True)
+
+                headers = MutableHeaders(raw=self.initial_message["headers"])
+                headers.add_vary_header("Accept-Encoding")
+                if body != message["body"]:
+                    headers["Content-Encoding"] = self.content_encoding
+                    del headers["Content-Length"]
+                    message["body"] = body
+
+                await self.send(self.initial_message)
+                await self.send(message)
+        elif message_type == "http.response.body":  # pragma: no branch
+            # Remaining body in streaming response.
+            body = message.get("body", b"")
+            more_body = message.get("more_body", False)
+
+            message["body"] = self.apply_compression(body, more_body=more_body)
+
+            await self.send(message)
+
+    def apply_compression(self, body: bytes, *, more_body: bool) -> bytes:
+        """Apply compression on the response body.
+
+        If more_body is False, any compression file should be closed. If it
+        isn't, it won't be closed automatically until all background tasks
+        complete.
+        """
+        return body
+
+
+class GZipResponder(IdentityResponder):
+    content_encoding = "gzip"
+
+    def __init__(self, app: ASGIApp, minimum_size: int, compresslevel: int = 9) -> None:
+        super().__init__(app, minimum_size)
+
+        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:
+        with self.gzip_buffer, self.gzip_file:
+            await super().__call__(scope, receive, send)
+
+    def apply_compression(self, body: bytes, *, more_body: bool) -> bytes:
+        self.gzip_file.write(body)
+        if not more_body:
+            self.gzip_file.close()
+
+        body = self.gzip_buffer.getvalue()
+        self.gzip_buffer.seek(0)
+        self.gzip_buffer.truncate()
+
+        return body
+
+
+async def unattached_send(message: Message) -> typing.NoReturn:
+    raise RuntimeError("send awaitable not set")  # pragma: no cover