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//===-- examples/mqtt-client/mqtt-client.cpp --------------------*- C++ -*-===//
//
// The RoSA Framework
//
// Distributed under the terms and conditions of the Boost Software License 1.0.
// See accompanying file LICENSE.
//
// If you did not receive a copy of the license file, see
// http://www.boost.org/LICENSE_1_0.txt.
//
//===----------------------------------------------------------------------===//
///
/// \file examples/mqtt-client/mqtt-client.cpp
///
/// \author David Juhasz (david.juhasz@tuwien.ac.at)
///
/// \date 2020
///
/// \brief An example showcasing the basic usage of paho-mqttpp3.
///
//===----------------------------------------------------------------------===//
#include "rosa/config/version.h"
#include "rosa/support/diagnostics.h"
#include "rosa/support/log.h"
#include "rosa/support/terminal_colors.h"
#include "cxxopts/cxxopts.hpp"
// NOTE: MSVC warns about some things in the following header.
ROSA_DISABLE_WARNING_PUSH
ROSA_DISABLE_WARNING_MSVC_C4100
ROSA_DISABLE_WARNING_MSVC_C4201
#include "mqtt/async_client.h"
ROSA_DISABLE_WARNING_POP
#include <chrono>
#include <iostream>
#include <thread>
using namespace rosa;
using namespace rosa::terminal;
/**
* Local callback & listener class for use with the client connection.
* This implementation is to receive messages but the mqtt::callback interface
* allows further actions to be defined.
*/
class MQTTCallback : public virtual mqtt::callback {
/** Callback for when a message arrives.
* @param Msg Pointer for the MQTT message
**/
void message_arrived(mqtt::const_message_ptr Msg) override {
std::string Topic = Msg->get_topic();
std::string Message = Msg->to_string();
LOG_INFO_STREAM << "[Message @ " << Topic << "] " << Message << std::endl;
}
public:
/** Constructor **/
MQTTCallback(void) noexcept = default;
};
/// Helper function to print an error message in red color to the terminal and
/// exit from the application.
///
/// \note The function never returns as it calles `exit()`.
///
/// \param Error error message
/// \param ExitCode exit code to return from the application
void logErrorAndExit(const std::string &Error, const int ExitCode) {
LOG_ERROR_STREAM << Color::Red << Error << Color::Default << std::endl;
exit(ExitCode);
}
int main(int argc, char *argv[]) {
// std::cout << "Das da?" << std::endl;
/// Host name of the MQTT server
std::string ServerHost = "localhost";
/// Port number of the MQTT server
uint16_t ServerPort = 1883;
/// MQTT topic
std::string Topic = "test";
/// Message to publish. Subscribe and log messages otherwise.
std::string Message = "";
/// How long to receive messages.
const size_t TimeoutSecs = 60;
// Handle command-line arguments.
try {
cxxopts::Options Options(argv[0],
library_string() + " -- PahoMQTT CPP Client Example");
Options.add_options()(
"host", "Server host",
cxxopts::value(ServerHost)->default_value("localhost"))(
"port", "Server port",
cxxopts::value(ServerPort)->default_value("1883"))(
"t,topic", "MQTT topic", cxxopts::value(Topic)->default_value("test"))(
"m,message",
"Message to publish (subscribe and log messages otherwise)",
cxxopts::value(Message))("h,help", "Print usage");
auto Args = Options.parse(argc, argv);
if (Args.count("help")) {
LOG_INFO_STREAM << '\n' << Options.help() << std::endl;
exit(0);
}
} catch (const cxxopts::OptionException &e) {
logErrorAndExit(e.what(), 1);
} catch (const std::invalid_argument &e) {
logErrorAndExit(e.what(), 1);
}
try {
std::stringstream ss;
ss << "tcp://" << ServerHost << ":" << ServerPort;
const std::string ServerURI = ss.str();
LOG_INFO_STREAM << "Initializing for " << ServerURI << std::endl;
mqtt::async_client Client(ServerURI, "");
LOG_INFO_STREAM << "Connecting to server" << std::endl;
Client.connect()->wait();
if (!Message.empty()) {
LOG_INFO_STREAM << "Publishing message '" << Message << "' to topic '"
<< Topic << "'" << std::endl;
mqtt::topic T(Client, Topic);
T.publish(Message.c_str())->wait();
} else {
LOG_INFO_STREAM << "Receiving messages from topic '" << Topic
<< "' for a short while..." << std::endl;
MQTTCallback Callback;
Client.set_callback(Callback);
Client.subscribe(Topic, {});
std::this_thread::sleep_for(std::chrono::seconds(TimeoutSecs));
}
LOG_INFO_STREAM << "Disconnecting from the server" << std::endl;
Client.disconnect()->wait();
} catch (const mqtt::exception &e) {
logErrorAndExit(e.what(), 1);
}
LOG_INFO_STREAM << "Done." << std::endl;
return 0;
}

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