fix streaming: use client.send() with stream=True instead of context manager

proxy/client.py

@@ -65,17 +65,20 @@ async def forward_request(provider: Provider, real_key: str, request: Request, b
     async with httpx.AsyncClient(timeout=_TIMEOUT, follow_redirects=True) as client:
         try:
             if stream:
-                async with client.stream("POST", target_url, headers=headers, json=body) as upstream:
-                    if upstream.status_code >= 400:
-                        content = await upstream.aread()
-                        logger.warning("Upstream error from %s: %d %s", provider.name, upstream.status_code, content[:500])
-                        raise HTTPException(status_code=upstream.status_code, detail=content.decode("utf-8", errors="replace"))
-                    return StreamingResponse(
-                        _stream_chunks(upstream),
-                        status_code=upstream.status_code,
-                        media_type=upstream.headers.get("content-type", "text/event-stream"),
-                        headers={k: v for k, v in upstream.headers.items() if k.lower() in ("cache-control", "x-request-id")},
-                    )
+                req = client.build_request("POST", target_url, headers=headers, json=body)
+                upstream = await client.send(req, stream=True)
+
+                if upstream.status_code >= 400:
+                    content = await upstream.aread()
+                    logger.warning("Upstream error from %s: %d %s", provider.name, upstream.status_code, content[:500])
+                    raise HTTPException(status_code=upstream.status_code, detail=content.decode("utf-8", errors="replace"))
+
+                return StreamingResponse(
+                    _stream_chunks(upstream),
+                    status_code=upstream.status_code,
+                    media_type=upstream.headers.get("content-type", "text/event-stream"),
+                    headers={k: v for k, v in upstream.headers.items() if k.lower() in ("cache-control", "x-request-id")},
+                )
             else:
                 upstream = await client.post(target_url, headers=headers, json=body)
         except httpx.TimeoutException as exc: