Red Hat Summit Red Hat SummitSupportConsoleDéveloppeursCommencer un essaiContact

Ce contenu n'est pas disponible dans la langue sélectionnée.

Chapter 9. Message delivery

9.1. Sending messages
Copier lien

To send a message, override the on_sendable event handler and call the sender::send() method. The sendable event fires when the proton::sender has enough credit to send at least one message.

Example: Sending messages

struct example_handler : public proton::messaging_handler {
    void on_container_start(proton::container& cont) override {
        proton::connection conn = cont.connect("amqp://example.com");
        conn.open_sender("jobs");
    }

    void on_sendable(proton::sender& snd) override {
        proton::message msg {"job-1"};
        snd.send(msg);
    }
};
Copy to Clipboard Toggle word wrap

9.2. Tracking sent messages
Copier lien

When a message is sent, the sender can keep a reference to the tracker object representing the transfer. The receiver accepts or rejects each message that is delivered. The sender is notified of the outcome for each tracked delivery.

To monitor the outcome of a sent message, override the on_tracker_accept and on_tracker_reject event handlers and map the delivery state update to the tracker returned from send().

Example: Tracking sent messages

void on_sendable(proton::sender& snd) override {
    proton::message msg {"job-1"};
    proton::tracker trk = snd.send(msg);
}

void on_tracker_accept(proton::tracker& trk) override {
    std::cout << "Delivery for " << trk << " is accepted\n";
}

void on_tracker_reject(proton::tracker& trk) override {
    std::cout << "Delivery for " << trk << " is rejected\n";
}
Copy to Clipboard Toggle word wrap

The tracker object has a tag() method for accessing the unique identifier for each delivery. The delivery tag can be used to store in-flight messages for resending after a connection failure.

9.3. Receiving messages
Copier lien

To receive messages, create a receiver and override the on_message event handler.

Example: Receiving messages

struct example_handler : public proton::messaging_handler {
    void on_container_start(proton::container& cont) override {
        proton::connection conn = cont.connect("amqp://example.com");
        conn.open_receiver("jobs");
    }

    void on_message(proton::delivery& dlv, proton::message& msg) override {
        std::cout << "Received message '" << msg.body() << "'\n";
    }
};
Copy to Clipboard Toggle word wrap

The delivery object has a tag() method for accessing the unique identifier for each delivery.

9.4. Acknowledging received messages
Copier lien

To explicitly accept or reject a delivery, use the delivery::accept() or delivery::reject() methods in the on_message event handler.

Example: Acknowledging received messages

void on_message(proton::delivery& dlv, proton::message& msg) override {
    try {
        process_message(msg);
        dlv.accept();
    } catch (std::exception& e) {
        dlv.reject();
    }
}
Copy to Clipboard Toggle word wrap

By default, if you do not explicitly acknowledge a delivery, then the library accepts it after on_message returns. To disable this behavior, set the auto_accept receiver option to false.

Retour au début
Red Hat logoGithubredditYoutubeTwitter

Apprendre

Essayez, achetez et vendez

Communautés

À propos de la documentation Red Hat

Nous aidons les utilisateurs de Red Hat à innover et à atteindre leurs objectifs grâce à nos produits et services avec un contenu auquel ils peuvent faire confiance. Découvrez nos récentes mises à jour.

Rendre l’open source plus inclusif

Red Hat s'engage à remplacer le langage problématique dans notre code, notre documentation et nos propriétés Web. Pour plus de détails, consultez le Blog Red Hat.

À propos de Red Hat

Nous proposons des solutions renforcées qui facilitent le travail des entreprises sur plusieurs plates-formes et environnements, du centre de données central à la périphérie du réseau.

Theme

© 2025 Red Hat