fix: use sparkplugb decoder only for spBv1.0 topic

backend/src/Model/sparkplugb.ts

@@ -9,7 +9,7 @@ const root = protobuf.parse(protocol).root
 export let SparkplugPayload = root.lookupType('com.cirruslink.sparkplug.protobuf.Payload')
 
 export const SparkplugDecoder = {
-  decode(input: Buffer): Base64Message | undefined {
+  decode(input: Buffer): Base64Message {
     try {
       const message = Base64Message.fromString(
         JSON.stringify(SparkplugPayload.toObject(SparkplugPayload.decode(new Uint8Array(input))))
@@ -17,8 +17,9 @@ export const SparkplugDecoder = {
       message.decoder = Decoder.SPARKPLUG
       return message
     } catch {
-      // ignore
+      const message = Base64Message.fromString("Failed to decode sparkplugb payload")
+      message.decoder = Decoder.NONE
+      return message
     }
-    return undefined
   },
 }

backend/src/index.ts

@@ -47,9 +47,16 @@ export class ConnectionManager {
         buffer = buffer.slice(0, 20000)
       }
 
+      let decoded_payload = null
+      if (topic.startsWith("spBv1.0/")) {
+        decoded_payload = SparkplugDecoder.decode(buffer)
+      } else {
+        decoded_payload = Base64Message.fromBuffer(buffer)
+      }
+
       backendEvents.emit(messageEvent, {
         topic,
-        payload: SparkplugDecoder.decode(buffer) ?? Base64Message.fromBuffer(buffer),
+        payload: decoded_payload,
         qos: packet.qos,
         retain: packet.retain,
         messageId: packet.messageId,