GeezerVison

mqttcpp is a modern, lightweight, and high-performance MQTT library written in C++20. It provides both client and broker implementations and includes advanced features such as authentication, retained messages, QoS levels, user and session management, and built-in security controls.

• Full MQTT 3.1.1 / 5.0 protocol support
• Integrated broker and client implementation
• QoS 0, 1, and 2 message delivery
• Topic wildcards (+ and #)
• Retained messages and persistence
• User authentication and access roles
• Security features (login limits, rate control, etc.)
• Session handling and concurrent client management
• Multi-threaded message processing
• Optional TLS and logging support

The project includes a complete test program, complete_test.cpp, which runs a full series of integration tests covering all major features of mqttcpp.

• C++20 compatible compiler (GCC ≥ 10, Clang ≥ 12, or MSVC ≥ 2019)
• CMake ≥ 3.16
• SQLite3
• OpenSSL (for TLS support)
• pthread (Linux/macOS)

git clone https://github.com/JustVugg/Mqttcpp.git
cd Mqttcpp
mkdir build && cd build
cmake ..
make -j4

This will compile:

• The Mqtcpp core library
• The full integration test executable (mqtt_tests)

If you prefer, you can also compile it directly:

g++ complete_test.cpp -std=c++20 -pthread -lsqlite3 -lssl -lcrypto -o mqtt_tests

Run the compiled executable:

./mqtt_tests

You’ll see each test section printed clearly in the console:

========================================
 Test 2: Single Topic Pub/Sub
========================================
Subscribed to test/topic
Published: Hello MQTT World!
✅ Single Topic Pub/Sub PASSED

At the end, you’ll get a summary:

==================================================
                 TEST RESULTS                    
==================================================
  Total Tests: 12
  Passed: 12
  Failed: 0

*** ALL TESTS PASSED! The library works perfectly! ***

🧠 Note: Each test uses a dedicated broker on ports 11883–11887. Make sure no other MQTT services (e.g., Mosquitto) are running on these ports.

#include "mqtt_broker.hpp"
using namespace mqttcpp;

int main() {
    BrokerConfig cfg;
    cfg.port = 1883;
    cfg.require_auth = false;

    MqttBroker broker(cfg);
    broker.start();

    std::cout << "Broker running on port 1883...\n";
    std::cin.get();
}

#include "mqtt_client.hpp"
using namespace mqttcpp;

int main() {
    MqttClient client("example_client");
    client.connect("localhost", 1883);

    client.subscribe("demo/topic", QOS_0);
    client.publish("demo/topic", "Hello MQTT!", QOS_0);

    std::this_thread::sleep_for(std::chrono::seconds(1));
    client.disconnect();
}

• User database via SQLite
• Password policies (length, symbols, etc.)
• Login attempt limits per IP
• Role-based authorization
• Session caps per user
• Persistent storage and optional encryption

mqttcpp is optimized for speed:

• Lock-free message dispatch
• Threaded network I/O
• Efficient buffering
• Minimal latency between clients

The performance test (test 8) demonstrates high throughput even with 1000+ messages exchanged.

mqttcpp/
├── mqtt_broker.hpp
├── mqtt_client.hpp
├── logger.hpp
├── other_source_files.cpp / .hpp
└── test_basic.cpp

Author: JustVugg License: MIT License

You are free to use, modify, and distribute this library in personal or commercial projects.

Pull requests and issues are welcome! If you add features or bug fixes, please include:

• Clear commit messages
• Tests for your changes
• Updated documentation if needed

If you encounter a problem or have a feature request, please open an issue on GitHub with:

• System and compiler details
• Steps to reproduce
• Any relevant output or logs