Console CoAP Client Example

 // Copyright (C) 2017 Witekio.
 // Copyright (C) 2018 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only

 #include "coaphandler.h"

 #include <QDebug>
 #include <QLoggingCategory>
 #include <QCoapClient>
 #include <QCoapReply>
 #include <QCoapResourceDiscoveryReply>

 Q_LOGGING_CATEGORY(lcCoapClient, "qt.coap.client")

 CoapHandler::CoapHandler(QObject *parent) : QObject(parent)
 {
     connect(&m_coapClient, &QCoapClient::finished, this, &CoapHandler::onFinished);
     connect(&m_coapClient, &QCoapClient::error, this, &CoapHandler::onError);
     connect(&m_coapClient, &QCoapClient::responseToMulticastReceived,
             this, &CoapHandler::onResponseToMulticast);
 }

 bool CoapHandler::runGet(const QUrl &url)
 {
     return m_coapClient.get(url);
 }

 bool CoapHandler::runPost(const QUrl &url)
 {
     return m_coapClient.post(url);
 }

 bool CoapHandler::runPut(const QUrl &url)
 {
     return m_coapClient.put(url);
 }

 bool CoapHandler::runDelete(const QUrl &url)
 {
     return m_coapClient.deleteResource(url);
 }

 bool CoapHandler::runObserve(const QUrl &url)
 {
     QCoapReply *observeReply = m_coapClient.observe(url);
     if (!observeReply)
         return false;

     connect(observeReply, &QCoapReply::notified, this, &CoapHandler::onNotified);
     return true;
 }

 bool CoapHandler::runDiscover(const QUrl &url)
 {
     QCoapResourceDiscoveryReply *discoverReply = m_coapClient.discover(url);
     if (!discoverReply)
         return false;

     connect(discoverReply, &QCoapResourceDiscoveryReply::discovered, this, &CoapHandler::onDiscovered);
     return true;
 }

 void CoapHandler::onFinished(QCoapReply *reply)
 {
     if (reply->errorReceived() == QtCoap::Error::Ok)
         qCInfo(lcCoapClient) << "Request finished with payload:" << reply->readAll();
     else
         qCWarning(lcCoapClient, "Request failed");

     // Don't forget to remove the reply
     reply->deleteLater();
 }

 void CoapHandler::onNotified(QCoapReply *reply, QCoapMessage message)
 {
     Q_UNUSED(message)

     // You can alternatively use `message.payload();`
     qCInfo(lcCoapClient) << "Received Observe notification with payload:" << reply->readAll();
 }

 void CoapHandler::onDiscovered(QCoapResourceDiscoveryReply *reply, QList<QCoapResource> resources)
 {
     Q_UNUSED(reply)

     for (const QCoapResource &res : qAsConst(resources))
         qCInfo(lcCoapClient) << "Discovered resource:" << res.path() << res.title();
 }

 void CoapHandler::onResponseToMulticast(QCoapReply *reply, const QCoapMessage& message,
                                         const QHostAddress &sender)
 {
     if (reply->errorReceived() == QtCoap::Error::Ok)
         qCInfo(lcCoapClient) << "Got a response for multicast request from:" << sender.toString()
                              << "with payload:" << message.payload();
     else
         qCWarning(lcCoapClient, "Multicast request failed");
 }

 void CoapHandler::onError(QCoapReply *reply, QtCoap::Error error)
 {
     if (reply)
         qCInfo(lcCoapClient) << "CoAP reply error:" << reply->errorString();
     else
         qCWarning(lcCoapClient) << "CoAP error:" << error;
 }