Smart Greenhouse IoT Backend

This repository contains the backend for a Smart Greenhouse System designed for remote monitoring and control of environmental conditions. The backend is built on a robust IoT architecture using the MQTT protocol for hardware communication and a secure REST API with WebSockets for client-side interaction.

Key Features

• Real-time Sensor Monitoring: Receive live sensor data (temperature, humidity, soil moisture) via MQTT and stream it directly to client dashboards using Socket.IO.

• Comprehensive Remote Control: Securely control a full range of actuators via the API, including:

  • Fan
  • Lamp
  • Water Pump
  • Solenoid Valve

• Advanced Authentication: Secure user registration and login with a JWT-based system (Access & Refresh Tokens) stored in httpOnly cookies to protect against XSS attacks.

• Hardware State Synchronization (Ack): The system listens for state acknowledgment messages from the hardware. This ensures the backend and frontend are always in sync with the actual state of the physical devices.

• Autonomous Hardware Logic Support (Edge Logic): The architecture supports hardware that can make autonomous decisions (e.g., turn on a fan if the temperature exceeds a threshold) and report its new state back to the server for seamless synchronization.

• Reporting System: Generate detailed statistical reports (average, minimum, maximum, count) for any sensor over custom date ranges using MongoDB's aggregation framework.

• GPS Tracking (NEW): Receives and stores real-time GPS data (latitude, longitude, altitude) from hardware via MQTT.

• Modular & Scalable Architecture: Logically separated controllers, models, and routes make the codebase easy to maintain, test, and extend.

Technology Stack

• Platform: Node.js
• Framework: Express.js
• Database: MongoDB (with Mongoose ODM)
• IoT Protocol: MQTT
• Real-time Client Communication: Socket.IO
• Authentication: JSON Web Tokens (JWT), bcrypt
• Validation: express-validator
• Environment Management: dotenv

Project Architecture

The system uses a decoupled, event-driven architecture to ensure reliability and real-time performance.

1. Data Ingestion (Sensor → Backend): Hardware sensors publish data to specific MQTT topics (e.g., greenhouse/temperature). The backend's MQTT client subscribes to these topics, saves the data to MongoDB, and pushes a sensor_update event to all connected web clients via Socket.IO.

2. Command Dispatch (Client → Backend → Hardware): A user sends a command from the frontend to a secure API endpoint. The backend validates the request and publishes a command message to the greenhouse/control/command MQTT topic. The hardware subscribes to this topic and executes the command.

3. State Synchronization (Hardware → Backend → Client): After executing a command or taking autonomous action, the hardware publishes a complete JSON payload of its current state to the greenhouse/state/relay topic. The backend receives this "acknowledgment," processes it, and emits a relay_state_update event via Socket.IO to synchronize all client dashboards with the ground truth.

Getting Started

Prerequisites

• Node.js (v16 or higher)
• MongoDB
• An MQTT Broker (e.g., Mosquitto, EMQ X)

Installation

1. Clone the repository: bash git clone [your-repo-url] cd [your-repo-name]

2. Install dependencies: bash npm install

3. Create a .env file in the root directory and populate it with your configuration:

   # Server Port
   PORT=2000
   
   # MongoDB Connection URI
   MONGODB_URI=mongodb://localhost:27017/smart_greenhouse
   
   # JWT Secrets (use long, random strings in production)
   ACCESS_TOKEN_SECRET=your_strong_access_token_secret
   REFRESH_TOKEN_SECRET=your_strong_refresh_token_secret
   
   # MQTT Broker URL
   MQTT_BROKER_URL=mqtt://localhost:1883

4. Run the server: bash npm start

The server will be available at http://localhost:2000.

API Endpoints

Authentication (/auth)

• POST /auth/register -- Register a new user.
• POST /auth/login -- Login and receive tokens in secure cookies.
• POST /auth/refresh -- Get a new access token using a refresh token.
• POST /auth/logout -- Invalidate the user session.

Sensor Data (/)

• GET /sensor-summary -- Get a summary of the latest sensor readings.
• GET /sensor-last10 -- Get the last 10 historical records for each sensor.

Control (/)

• GET /get-control -- Get the last known actuator status from the server.
• POST /set-control -- Update actuator status.
  • Request Body: { "fan": 1, "lamp": 0, "pump": 1, "valve": 0 }

Reporting (/)

• GET /reports -- Generate a statistical report.
  • Query Params: startDate=YYYY-MM-DD&endDate=YYYY-MM-DD

GPS Location (/)

• GET /gps-latest -- Returns latest GPS location.

  • Response Example:

    {
      "latitude": 35.6892,
      "longitude": 51.389,
      "altitude": 1273,
      "timestamp": "2025-09-19T10:15:30.000Z"
    }

Location (/location - Future Implementation)

• GET /location/last -- Get the last reported GPS location.

MQTT Topics

Topics Subscribed To by Backend (Incoming Data)

• greenhouse/temperature: For temperature sensor data.
• greenhouse/humidity: For humidity sensor data.
• greenhouse/soil: For soil moisture sensor data.
• greenhouse/state/relay: For receiving full state/ack messages from hardware.
• greenhouse/location: For receiving GPS data.
• greenhouse/gps: (alternative topic naming)

Topics Published To by Backend (Outgoing Commands)

• greenhouse/control/command: For sending control commands to hardware.

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Outputs

Postman API Tests

MongoDB Collections test

Server Logs test

Example of server running with MQTT and MongoDB connections:

MongoDB connected
MQTT client connected successfully
Server is running on port 2000
Socket connected: b6HJds9SKX...

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Programmer

Shady Nikooei