mqtt-client

Racket MQTT client implementation based on paho.mqtt.c

Introduction

This package provides an MQTT client implementation enabling Racket applications to exchange messages with an MQTT broker. This client implementation is based on paho.mqtt.c using Racket's foreign function interface ffi/unsafe to wrap the synchronous MQTT library calls.

Example

#lang racket/base

(require mqtt-client)

(mqtt/with-client ("localhost" "client1")

  (mqtt/with-qos ('qos-1)
  
    (mqtt/with-connection (#:keep-alive-interval 20
                           #:clean-session       #t)

                           
      (mqtt/subscribe "some-topic")

      (mqtt/publish "some-topic" "Hello world")

      (mqtt/with-message-recv (topic payload)
        (displayln topic)
        (displayln payload)))))

Related Work

• mosquitto-ffi An FFI binding of libmosquitto for racket

Prerequisites

paho.mqtt.c Library

As this MQTT client wraps a library, this library must be present in the environment Racket is running in. E.g., on Ubuntu paho.mqtt.c can be installed by running:

sudo apt-get install -y libpaho-mqtt1.3

MQTT Broker

To exchange messages an MQTT broker must be available. Eclipse Mosquitto is a popular MQTT broker. To install Eclipse Mosquitto on Ubuntu run:

sudo apt-get install -y mosquitto

Verify the broker service is running be entering:

systemctl status mosquitto

Installation

from Racket Package Index Catalog

To install this package from the internet, run

raco pkg install mqtt-client

from Source

To install this package from this source repository in the mqtt-client directory run

raco pkg install

Removal

To remove this package run

raco pkg remove mqtt-client