CORS headers missing on SSE streaming endpoints

Fixes on record

Merged to main. A stamp counts the issues a fix is linked to.

• #3573 fix(api-server): add CORS headers to streaming SSE responses

  merged to main

  files: gateway/platforms/api_server.py

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  • gateway/platforms/api_server.py

    @@ -582,10 +582,14 @@ async def _write_sse_chat_completion(
             """
             import queue as _q
     
    -        response = web.StreamResponse(
    -            status=200,
    -            headers={"Content-Type": "text/event-stream", "Cache-Control": "no-cache"},
    -        )
    +        sse_headers = {"Content-Type": "text/event-stream", "Cache-Control": "no-cache"}
    +        # CORS middleware can't inject headers into StreamResponse after
    +        # prepare() flushes them, so resolve CORS headers up front.
    +        origin = request.headers.get("Origin", "")
    +        cors = self._cors_headers_for_origin(origin) if origin else None
    +        if cors:
    +            sse_headers.update(cors)
    +        response = web.StreamResponse(status=200, headers=sse_headers)
             await response.prepare(request)
     
             try: