feat(gateway): added reply to the POST request with the latest measurement

Signed-off-by: Klagarge <remi@heredero.ch>

gateway/src/ProcessUpdate.go

@@ -41,6 +41,7 @@ func (m *Gateway) processUpdate(_ paho.Client, message paho.Message) {
 	err := json.Unmarshal(message.Payload(), &event)
 	if err != nil {
 		log.Errorf("invalid update event payload: %s", string(message.Payload()))
+		return
 	}
 
 	// Skip processing if no data points are provided.
@@ -48,6 +49,39 @@ func (m *Gateway) processUpdate(_ paho.Client, message paho.Message) {
 		return
 	}
 
+	// Check if there's a pending request for this user, room, and device
+	if m.pendingUser == user && m.pendingRoom == room && m.pendingDevice == device {
+		// Create a slice to hold the measurements
+		var measurements []map[string]interface{}
+		currentTime := time.Now().Format(time.RFC3339Nano)
+
+		// Convert each data point to a measurement
+		for field, value := range event.DataPoints {
+			// Create a measurement for this field
+			measurement := map[string]interface{}{
+				"time":  currentTime,
+				"type":  field,
+				"value": value,
+			}
+			measurements = append(measurements, measurement)
+		}
+
+		// Convert measurements to JSON
+		if len(measurements) > 0 {
+			responseData, err := json.Marshal(measurements)
+			if err == nil {
+				// Send the data as a response
+				select {
+				case m.pendingChan <- string(responseData):
+					// Response sent successfully
+				default:
+					// Channel is full or closed, log an error
+					log.Errorf("failed to send response to pending channel")
+				}
+			}
+		}
+	}
+
 	// Prepare the InfluxDB point with tags and fields.
 	MEASUREMENT_NAME, ok := os.LookupEnv("MEASUREMENT_NAME")
 	if !ok {