MqttRecordBuilder

Kind: Class

Source: packages/microservices/record-builders/mqtt.record-builder.ts

Part of: Microservices

MqttRecordBuilder constructs MqttRecord instances for MQTT message handling within the microservices transport layer. It provides a fluent API for configuring payload data, QoS, retain and duplicate flags, and MQTT v5 properties before creating an immutable record with build().

Methods

Diagram

mermaid
graph LR
  A[Message Payload] --> B[MqttRecordBuilder]
  C[QoS / Retain / Dup Flags] --> B
  D[MQTT Properties] --> B
  B -->|build()| E[MqttRecord]
  E --> F[MQTT Transport / Broker]

Usage

ts
import { MqttRecordBuilder } from './mqtt.record-builder';

const record = new MqttRecordBuilder()
  .setData(Buffer.from(JSON.stringify({ event: 'order.created', orderId: '123' })))
  .setQoS(1)
  .setRetain(false)
  .setDup(false)
  .setProperties({
    contentType: 'application/json',
  })
  .build();

// Pass the record to the MQTT publishing or transport layer.

AI Coding Instructions

• Use the fluent setter pattern: configure all required values through setData(), setQoS(), and optional MQTT flags before calling build().
• Validate payload format and QoS values at the integration boundary; MQTT QoS must match the broker and client capabilities.
• Use setRetain(true) only for messages intended to be stored by the broker and delivered to future subscribers.
• Set dup only when handling MQTT redelivery behavior; it should not be used as a general retry indicator.
• Keep MQTT v5 metadata in setProperties() and ensure property names and values are compatible with the MQTT client implementation.

Used by

1 reference from 1 file. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

Imported by (1)

• MqttController — integration/microservices/src/mqtt/mqtt.controller.ts:16