sse iphone fix 1

apps/api/main.py

@@ -287,7 +287,13 @@ async def set_device(device_id: str, request: SetDeviceRequest) -> dict[str, str
 
 
 async def event_generator(request: Request) -> AsyncGenerator[str, None]:
-    """Generate SSE events from Redis Pub/Sub.
+    """Generate SSE events from Redis Pub/Sub with Safari compatibility.
+    
+    Safari-compatible features:
+    - Immediate retry hint on connection
+    - Regular heartbeats every 15s (comment-only, no data)
+    - Proper flushing after each yield
+    - Graceful disconnect handling
     
     Args:
         request: FastAPI request object for disconnect detection
@@ -295,17 +301,28 @@ async def event_generator(request: Request) -> AsyncGenerator[str, None]:
     Yields:
         str: SSE formatted event strings
     """
-    redis_url, redis_channel = get_redis_settings()
-    redis_client = await aioredis.from_url(redis_url, decode_responses=True)
-    pubsub = redis_client.pubsub()
+    redis_client = None
+    pubsub = None
     
     try:
+        # Send retry hint immediately for EventSource reconnect behavior
+        yield "retry: 2500\n\n"
+        
+        # Try to connect to Redis
+        redis_url, redis_channel = get_redis_settings()
+        try:
+            redis_client = await aioredis.from_url(redis_url, decode_responses=True)
+            pubsub = redis_client.pubsub()
             await pubsub.subscribe(redis_channel)
             logger.info(f"SSE client connected, subscribed to {redis_channel}")
+        except Exception as e:
+            logger.warning(f"Redis unavailable, running in heartbeat-only mode: {e}")
+            redis_client = None
+            pubsub = None
         
-        # Create heartbeat tracking
+        # Heartbeat tracking
         last_heartbeat = asyncio.get_event_loop().time()
-        heartbeat_interval = 25
+        heartbeat_interval = 15  # Safari-friendly: shorter interval
         
         while True:
             # Check if client disconnected
@@ -313,29 +330,58 @@ async def event_generator(request: Request) -> AsyncGenerator[str, None]:
                 logger.info("SSE client disconnected")
                 break
             
-            # Try to get message (non-blocking)
-            message = await pubsub.get_message(ignore_subscribe_messages=True, timeout=0.1)
+            # Try to get message from Redis (if available)
+            if pubsub:
+                try:
+                    message = await asyncio.wait_for(
+                        pubsub.get_message(ignore_subscribe_messages=True),
+                        timeout=0.1
+                    )
                     
-            # Handle actual data messages
                     if message and message["type"] == "message":
                         data = message["data"]
                         logger.debug(f"Sending SSE message: {data[:100]}...")
                         yield f"event: message\ndata: {data}\n\n"
                         last_heartbeat = asyncio.get_event_loop().time()
-            else:
-                # No message, sleep a bit to avoid busy loop
+                        continue  # Skip sleep, check for more messages immediately
+                        
+                except asyncio.TimeoutError:
+                    pass  # No message, continue to heartbeat check
+                except Exception as e:
+                    logger.error(f"Redis error: {e}")
+                    # Continue with heartbeats even if Redis fails
+            
+            # Sleep briefly to avoid busy loop
             await asyncio.sleep(0.1)
             
-            # Send heartbeat every 25 seconds
+            # Send heartbeat if interval elapsed
             current_time = asyncio.get_event_loop().time()
             if current_time - last_heartbeat >= heartbeat_interval:
-                yield "event: ping\ndata: heartbeat\n\n"
+                # Comment-style ping (Safari-compatible, no event type)
+                yield ": ping\n\n"
                 last_heartbeat = current_time
             
+    except asyncio.CancelledError:
+        logger.info("SSE connection cancelled by client")
+        raise
+    except Exception as e:
+        logger.error(f"SSE error: {e}")
+        raise
     finally:
+        # Cleanup Redis connection
+        if pubsub:
+            try:
                 await pubsub.unsubscribe(redis_channel)
                 await pubsub.aclose()
+            except Exception as e:
+                logger.error(f"Error closing pubsub: {e}")
+        
+        if redis_client:
+            try:
                 await redis_client.aclose()
+            except Exception as e:
+                logger.error(f"Error closing redis: {e}")
+        
         logger.info("SSE connection closed")
 
 
@@ -343,24 +389,29 @@ async def event_generator(request: Request) -> AsyncGenerator[str, None]:
 async def realtime_events(request: Request) -> StreamingResponse:
     """Server-Sent Events endpoint for real-time updates.
     
+    Safari-compatible SSE implementation:
+    - Immediate retry hint (2.5s reconnect delay)
+    - Heartbeat every 15s using comment syntax ": ping"
+    - Proper Cache-Control headers
+    - No buffering (nginx compatibility)
+    - Graceful Redis fallback (heartbeat-only mode)
+    
     Args:
         request: FastAPI request object
         
     Returns:
-        StreamingResponse: SSE stream of Redis messages
+        StreamingResponse: SSE stream with Redis messages and heartbeats
     """
     return StreamingResponse(
         event_generator(request),
         media_type="text/event-stream",
         headers={
-            "Cache-Control": "no-cache",
+            "Cache-Control": "no-cache, no-transform",
             "Connection": "keep-alive",
             "X-Accel-Buffering": "no",  # Disable nginx buffering
         }
     )
 
-    return {"message": f"Command sent to {device_id}"}
-
 
 def main() -> None:
     """Run the API application with uvicorn."""