From 44df2533c8da76a20108aa72cd5170b13811f271 Mon Sep 17 00:00:00 2001
From: Atridad Lahiji <me@atri.dad>
Date: Thu, 9 May 2024 14:32:19 -0600
Subject: [PATCH] No really... this time for real now.

---
 lib/sse.go | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/lib/sse.go b/lib/sse.go
index 8f2a1e1..09f5b28 100644
--- a/lib/sse.go
+++ b/lib/sse.go
@@ -98,28 +98,40 @@ func HandleIncomingMessages(c echo.Context, pubsub pubsub.PubSubMessage, client
 	var mutex sync.Mutex
 
 	for {
+		// Receive messages using the context of the request, which is cancelled when the client disconnects
 		msg, err := pubsub.ReceiveMessage(c.Request().Context())
 		if err != nil {
 			if err == context.Canceled {
-				// The client has disconnected. Stop trying to send messages.
+				// Log when the client disconnects and stop the message forwarding
 				LogInfo.Printf("Client disconnected, stopping message forwarding")
 				return
 			}
+			// Log errors other than client disconnection
 			LogError.Printf("Failed to receive message: %v", err)
 			return
 		}
 
+		// Skip processing if the message payload is empty
+		if msg.Payload == "" {
+			LogInfo.Printf("Received empty message, skipping processing")
+			continue
+		}
+
+		// Prepare the data string to be sent as an SSE
 		data := fmt.Sprintf("data: %s\n\n", msg.Payload)
 
+		// Locking before writing to the response writer to avoid concurrent write issues
 		mutex.Lock()
 		if c.Response().Writer != nil {
 			_, err := c.Response().Write([]byte(data))
 			if err != nil {
+				// Log failure to write and unlock before returning
 				LogError.Printf("Failed to write message: %v", err)
 				mutex.Unlock()
 				return
 			}
 
+			// Flush the response if possible
 			flusher, ok := c.Response().Writer.(http.Flusher)
 			if ok {
 				flusher.Flush()
@@ -129,6 +141,7 @@ func HandleIncomingMessages(c echo.Context, pubsub pubsub.PubSubMessage, client
 		} else {
 			LogError.Println("Failed to write: ResponseWriter is nil")
 		}
+		// Ensure the mutex is unlocked after processing each message
 		mutex.Unlock()
 	}
 }