Harper MQTT Getting Started

A complete MQTT messaging starter project featuring a Harper application with MQTT capabilities and client examples in multiple languages.

Overview

This repository provides everything you need to get started with MQTT messaging using Harper:

• Harper Application - A Harper application with built-in MQTT broker capabilities
• Client Examples - Publisher and subscriber implementations in Node.js, Python, and MQTTX CLI

Quick Start

1. Start the Harper Application

First, set up and run the Harper application:

cd harper
npm install
npm run dev

See the harper/README.md for detailed setup and configuration.

2. Run a Client

Once the Harper application is running, choose your preferred client implementation:

# Node.js
cd client/nodejs && npm install

# Python
cd client/python && pip install -r requirements.txt

# MQTTX CLI
cd client/mqttx && ./install.sh

Each client directory contains its own README with specific instructions.

Project Structure

harper-mqtt-getting-started/
├── harper/              # Harper application with MQTT broker
│   ├── config.yaml      # Application configuration
│   ├── schema.graphql   # Database schema
│   ├── resources.js     # Application logic
│   └── package.json
└── client/              # MQTT client examples
    ├── nodejs/          # Node.js MQTT examples
    │   ├── publisher.js
    │   ├── subscriber.js
    │   └── package.json
    ├── python/          # Python MQTT examples
    │   ├── publisher.py
    │   ├── subscriber.py
    │   └── requirements.txt
    └── mqttx/           # MQTTX CLI shell scripts
        ├── mqttx_publish.sh
        ├── mqttx_subscribe.sh
        └── install.sh

Client Implementations

Node.js

JavaScript MQTT clients using the mqtt npm package.

• Simple and widely-used MQTT library
• Supports modern async/await patterns
• Easy to integrate into existing Node.js projects

Python

Python MQTT clients using the paho-mqtt library.

• Industry-standard MQTT client library
• Clean and readable Python code
• Great for IoT and data processing applications

MQTTX CLI

Shell script examples using the MQTTX command-line tool.

• No programming required
• Quick testing and debugging
• Platform-agnostic command-line interface

Tier Structure

All client implementations follow the same tier progression:

• Tier 0 (MVP): Single message publish, no database persistence
• Tier 1: Enable database persistence with retain flag
• Tier 2: Continuous publishing every 5 seconds

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.