fix: fix proxy

backend/src/gateway/routers/proxy.py

@@ -51,29 +51,22 @@ EXCLUDED_HEADERS = {
 }
 
 
-async def stream_response(client: httpx.AsyncClient, method: str, url: str, headers: dict, body: bytes | None, timeout: float) -> AsyncGenerator[bytes, None]:
-    """Stream response from the upstream server.
+async def stream_sse_response(stream_ctx, response: httpx.Response) -> AsyncGenerator[bytes, None]:
+    """Stream SSE response from the upstream server.
 
     Args:
-        client: The httpx async client.
-        method: HTTP method.
-        url: Target URL.
-        headers: Request headers.
-        body: Request body.
-        timeout: Request timeout.
+        stream_ctx: The httpx stream context manager.
+        response: The httpx streaming response.
 
     Yields:
         Response chunks.
     """
-    async with client.stream(
-        method=method,
-        url=url,
-        headers=headers,
-        content=body,
-        timeout=timeout,
-    ) as response:
+    try:
         async for chunk in response.aiter_bytes():
             yield chunk
+    finally:
+        # Ensure stream is properly closed when done
+        await stream_ctx.__aexit__(None, None, None)
 
 
 async def proxy_request(request: Request, path: str) -> Response | StreamingResponse:
@@ -104,22 +97,26 @@ async def proxy_request(request: Request, path: str) -> Response | StreamingResp
     client = get_http_client()
 
     try:
-        # First, make a non-streaming request to check content type
-        response = await client.request(
+        # Use streaming request to avoid waiting for full response
+        # This allows us to check headers immediately and stream SSE without delay
+        stream_ctx = client.stream(
             method=request.method,
             url=target_url,
             headers=headers,
             content=body,
-            timeout=config.proxy_timeout,
+            timeout=config.stream_timeout,
         )
 
+        response = await stream_ctx.__aenter__()
+
         content_type = response.headers.get("content-type", "")
 
         # Check if response is SSE (Server-Sent Events)
         if "text/event-stream" in content_type:
-            # For SSE, we need to re-request with streaming
+            # For SSE, stream the response immediately
             return StreamingResponse(
-                stream_response(client, request.method, target_url, headers, body, config.stream_timeout),
+                stream_sse_response(stream_ctx, response),
+                status_code=response.status_code,
                 media_type="text/event-stream",
                 headers={
                     "Cache-Control": "no-cache",
@@ -128,13 +125,17 @@ async def proxy_request(request: Request, path: str) -> Response | StreamingResp
                 },
             )
 
+        # For non-SSE responses, read full content and close the stream
+        content = await response.aread()
+        await stream_ctx.__aexit__(None, None, None)
+
         # Prepare response headers
         response_headers = dict(response.headers)
         for header in ["transfer-encoding", "connection", "keep-alive"]:
             response_headers.pop(header, None)
 
         return Response(
-            content=response.content,
+            content=content,
             status_code=response.status_code,
             headers=response_headers,
         )