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    1. Products
    2. Pub/Sub
    3. Examples
    4. Connect with Rust

    Connect with Rust

    Below is an example using the paho.mqtt.rust crate with the TOKEN authentication mode configured on a Broker.

    The example below creates a simple subscriber, sends a message to the configured topic, and waits until the message is received before exiting.

    Make sure to set the BROKER_URI (e.g. mqtts://YOUR-BROKER.YOUR-NAMESPACE.cloudflarepubsub.com), BROKER_TOKEN (a valid auth token), and BROKER_TOPIC environmental variables before running the example program.

    # in your Cargo.toml

    paho-mqtt = "0.11.1"

    Create a file called example.rs with the following content, and use cargo run to build and run the example:

    use paho_mqtt::*;

    use std::thread;
     
    fn main() {
        // Specify MQTT broker hostname: <broker name>.<namespace>.cloudflarepubsub.com
        let uri = std::env::var("BROKER_URI").expect("URI must be set");
     
        // Your JWT token
        let jwt = std::env::var("BROKER_TOKEN").expect("JWT must be set");
     
        // Specify a topic name
        let topic = std::env::var("BROKER_TOPIC").expect("Topic must be set");
     
        // Configure the MQTT client
        let client_opts = CreateOptionsBuilder::new()
            .mqtt_version(MQTT_VERSION_5)
            .server_uri(uri)
            .finalize();
     
        // Connect options
        let options = ConnectOptionsBuilder::new()
            .ssl_options(SslOptions::default())
            .clean_start(true)
            .password(jwt)
            .finalize();
     
        // Create the MQTT client
        let cli = Client::new(client_opts).expect("Error creating client");
     
        // Connect to your broker
        cli.connect(options).expect("Error connecting to broker");
     
        // Message receiver
        let rx = cli.start_consuming();
     
        // Subscribe to a topic
        cli.subscribe(&topic, 0)
            .expect("Error subscribing to topic");
     
        // Start waiting for messages
        let reader = thread::spawn(move || match rx.recv().expect("Error receiving message") {
            Some(message) => {
                println!("{:?}", message);
            }
            None => {}
        });
     
        // Publish a message!
        cli.publish(Message::new(topic, "My first MQTT message", 0))
            .expect("Error publishing");
     
        // Wait until we have received our message
        let _ = reader.join();
     
        // Good-Bye
        cli.disconnect(DisconnectOptions::default())
            .expect("Error disconnecting");

    }