swift-mqtt

• An MQTT Client over TCP and QUIC protocol
• QUIC protocol only available in macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0, *

Why

• We already have some mqtt clients available like mqtt-nio, CocoaMQTT and so on, why do we write another one?

• mqtt-nio is built on swift-nio, and swift-nio needs to consider compatibility with platforms other than iOS, so the code dependency is a little too onerous for the iOS client. Although swift-nio can make the underlying implementation of swift-nio directly provided by the iOS Network framework through the introduction of swift-nio-transport-services, it is also difficult to accept.

• CocoaMQTT is built on CocoaAsyncSocket that is too old and doesn't support the QUIC protocol.

• swift-mqtt is a lightweight mqtt client focused on the iOS platform and provides QUIC protocol support. Of course, many of these implementations also refer to the previous two

Requirements

• iOS 13.0+ | macOS 10.15+ | tvOS 13.0+ | watchOS 6.0+
• Xcode 8

Integration

Swift Package Manager

You can use The Swift Package Manager to install swift-mqtt by adding the proper description to your Package.swift file:

// swift-tools-version:5.8
import PackageDescription

let package = Package(
    name: "YOUR_PROJECT_NAME",
    dependencies: [
        .package(url: "https://github.com/emqx/swift-mqtt.git", from: "0.2.1"),
    ]
)

Usage

import MQTT
import Foundation

let client = Client()

class Observer{
    @objc func statusChanged(_ notify:Notification){
        guard let info = notify.mqttStatus() else{
            return
        }
        Logger.info("observed: status: \(info.old)--> \(info.new)")
    }
    @objc func recivedMessage(_ notify:Notification){
        guard let info = notify.mqttMesaage() else{
            return
        }
        let str = String(data: info.message.payload, encoding: .utf8) ?? ""
        Logger.info("observed: message: \(str)")
    }
    @objc func recivedError(_ notify:Notification){
        guard let info = notify.mqttError() else{
            return
        }
        Logger.info("observed: error: \(info.error)")
    }
}
class Client:MQTTClient.V5,@unchecked Sendable{
    let observer = Observer()
    init() {
        var options = TLSOptions()
        options.trust = .trustAll
        options.credential = try? .create(from: "", passwd: "")
        options.serverName = "example.com"
        options.minVersion = .v1_2
        options.falseStartEnable = true
        super.init(UUID().uuidString, endpoint: .quic(host: "172.16.2.7",tls: options))
        MQTT.Logger.level = .debug
        self.config.keepAlive = 60
        self.config.pingTimeout = 5
        self.config.username = "test"
        self.config.password = "test"
        self.config.pingEnabled = true
        self.delegateQueue = .main
        /// start network monitor
        self.startMonitor()
        /// start auto reconnecting
        self.startRetrier{reason in
            switch reason{
            case .serverClose(let code):
                switch code{
                case .serverBusy,.connectionRateExceeded:// don't retry when server is busy
                    return true
                default:
                    return false
                }
            default:
                return false
            }
        }
        /// eg
        /// set simple delegate
        self.delegate = self
        /// eg.
        /// add multiple observer.
        /// Don't observe self. If necessary use delegate
        self.addObserver(observer, for: .status, selector: #selector(Observer.statusChanged(_:)))
        self.addObserver(observer, for: .message, selector: #selector(Observer.recivedMessage(_:)))
        self.addObserver(observer, for: .error, selector: #selector(Observer.recivedError(_:)))
    }
    
}
extension Client:MQTTDelegate{
    func mqtt(_ mqtt: MQTTClient, didUpdate status: Status, prev: Status) {
        Logger.info("delegate: status \(prev)--> \(status)")

    }
    func mqtt(_ mqtt: MQTTClient, didReceive error: any Error) {
        Logger.info("delegate: error \(error)")
    }
    func mqtt(_ mqtt: MQTTClient, didReceive message: Message) {
        let str = String(data: message.payload, encoding: .utf8) ?? ""
        Logger.info("delegate: message: \(str)")
    }
}


client.open()
client.close()
client.subscribe(to:"topic")
client.unsubscribe(from:"topic")
client.publish(to:"topic", payload: "hello mqtt qos2",qos: .exactlyOnce)