Edits history of script submission #11453 for ' MQTT trigger script template (windmill)'

• bun

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  /**
   * General Trigger Preprocessor Function
   * 
   * ⚠️ IMPORTANT: This preprocessor function is ALWAYS called FIRST, before the main function.
   * 
   * This example assumes the script was triggered by an MQTT event, but the same 
   * preprocessor can handle other trigger types by checking wm_trigger.kind.
   * 
   * Flow: 
   * 1. Trigger event occurs (MQTT message in this example)
   * 2. Preprocessor function is called FIRST
   * 3. Main function is called with the return values from preprocessor
   * 
   * You can transform the raw trigger data here before it reaches your main function.
   * Common transformations include:
   * - Converting binary payload to string or JSON
   * - Extracting metadata from the trigger source
   * - Filtering messages
   * - Adding timestamps or other context
   * 
   * IMPORTANT: The object you return from this preprocessor determines the parameters passed to your main function:
   * - If you return {a: 1, b: 2}, then main will be called as main(a, b)
   * - If you return {payload}, then main will be called as main(payload)
   * 
   * @param wm_trigger - Information about the trigger source (could be MQTT, HTTP, email, etc.)
   * @param payload - The raw data from the trigger (type depends on the trigger kind)
   * @returns An object with the arguments to pass to the main function
   */
  export async function preprocessor(
    wm_trigger: {
      kind: 'http' | 'email' | 'webhook' | 'websocket' | 'kafka' | 'nats' | 'postgres' | 'sqs' | 'mqtt',
      mqtt?: {
        topic: string,
        retain: boolean,
        pkid: number,
        qos: number,
        v5?: {
          payload_format_indicator?: number,
          topic_alias?: number,
          response_topic?: string,
          correlation_data?: Array<number>,
          user_properties?: Array<[string, string]>,
          subscription_identifiers?: Array<number>,
          content_type?: string
        }
      }
    },
    /**
   * Each trigger type has its own specific parameters:
   * - For MQTT: 'payload' (Uint8Array of raw message bytes)
   * - For SQS: 'msg' (message data)
   * - Other trigger types have their own specific properties
   */
    payload: Uint8Array,
  ) {
    if (wm_trigger.kind === 'mqtt' && wm_trigger.mqtt) {
  
      // Convert the binary payload to a string
      // This assumes the binary data represents a string (e.g., UTF-8 encoded text)
      const payloadAsString = new TextDecoder().decode(payload);
  
      return {
        contentType: wm_trigger.mqtt.v5?.content_type,
        payload,
        payloadAsString
      }
    }
    else {
      return {
        kind: wm_trigger.kind
      }
    }
  }
  
  /**
   * Main Function - Handles Trigger Events
   * 
   * ⚠️ This function is called AFTER the preprocessor function.
   * 
   * This example assumes we're handling an MQTT trigger event where the payload is a string.
   * The main function receives arguments based on what the preprocessor returned.
   * 
   * @param contentType - For MQTT: The content type from MQTT v5 properties if available
   * @param payload - The raw binary payload from MQTT
   * @param payloadAsString - The payload as a string (decoded from binary data)
   */
  export async function main(payload: string, contentType?: string, payloadAsString: string) {
  
  }

  Submitted by dieriba.pro916 441 days ago