Iris

Iris is a C++ application that integrates MQTT messaging with a PostgreSQL database. It listens to specified MQTT topics, processes messages, decrypts them if necessary, and stores them in a PostgreSQL database.

Features

• MQTT Integration: Uses the Mosquitto library to subscribe to and receive MQTT messages.
• PostgreSQL Storage: Saves incoming messages in a PostgreSQL database.
• AES Encryption Handling: Supports AES-CBC encrypted messages and decrypts them using OpenSSL.
• Configurable Topics: Reads topics and encryption keys from a JSON configuration file.
• JSON-Based Configuration: Uses jsoncpp to load database and MQTT settings dynamically.

Requirements

• C++ Compiler (e.g., g++ with C++17+ support)
• Mosquitto (MQTT client library)
• libpqxx (PostgreSQL C++ client library)
• OpenSSL (For AES decryption)
• jsoncpp (For JSON parsing)
• PostgreSQL Database Server

Installation

1. Install Dependencies

Ubuntu/Debian:

sudo apt update && sudo apt install -y libmosquitto-dev libpqxx-dev libssl-dev libjsoncpp-dev

MacOS (Homebrew):

brew install mosquitto libpqxx openssl jsoncpp

Windows (vcpkg):

vcpkg install mosquitto libpqxx openssl jsoncpp

2. Build the Project

mkdir build && cd build
cmake ..
make -j$(nproc)

Configuration

Create a config.json file in the root directory with the following structure:

{
    "mqtthost": "localhost",
    "mqttport": 1883,
    "mqtttimeout": 60,
    "postgresqlhost": "127.0.0.1",
    "postgresqlport": 5432,
    "postgresqldbname": "mydatabase",
    "postgresqluser": "myuser",
    "postgresqlpassword": "mypassword",
    "topics": [
        { "name": "sports/football", "aeskey": "your_aes_key_here" },
        { "name": "news/weather" }
    ]
}

Running the Application

./iris

Expected Output

Connected to database: mydatabase
Subscribed to: sports/football
Subscribed to: news/weather
Receiving messages.

Code Overview

Main Components

• iris.cpp
  • Loads configuration from config.json.
  • Connects to PostgreSQL.
  • Initializes IrisMQTTClient and subscribes to topics.
• irismqttclient.h / irismqttclient.cpp
  • Handles MQTT message reception.
  • Decrypts AES-CBC messages (if encrypted).
  • Stores messages in PostgreSQL.
• topic.h
  • Represents an MQTT topic with an optional AES key.

Database Schema

CREATE TABLE messages (
    id SERIAL PRIMARY KEY,
    topic VARCHAR(255) NOT NULL,
    message_payload TEXT NOT NULL,
    received_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

Contributing

Feel free to submit pull requests or report issues if you find bugs or improvements.

License

This project is licensed under the MIT License.

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Author: Matthew Grigajtis
Project: Iris