📊 Real-Time Polling Application API

A backend service for creating polls, voting, and getting live results in real-time using WebSockets.
Built with Node.js, Express, Prisma, PostgreSQL, and Socket.IO.

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Tech Stack

- Backend Framework : Node.js with Express.js  
- Database : PostgreSQL  
- ORM : Prisma  
- Authentication: JWT + bcryptjs  
- Real-time Communication : Socket.IO  

Getting Started

1. Clone the Repository

• git clone https://github.com/coder-nitin07/realtime-polling-app
• cd realtime-polling-app

2. Install Dependencies

npm install

Database Setup

1. Initialize Prisma

npx prisma init

2. Run Migrations

npx prisma migrate dev --name init

3. Generate Prisma Client

npx prisma generate

4. Run the Server

npm run dev

Authentication

- JWT-based authentication
- Include token in header:
    Authorization: Bearer <your-token>

API Endpoints

a. Users
    - Register → POST /users
        {
            "name": "John Doe",
            "email": "john@example.com",
            "password": "mypassword"
        }

    - Login → POST /auth/login
        {
            "email": "john@example.com",
            "password": "mypassword"
        }

    
    - Response: 
        {
           "token": "your-jwt-token"
        }

Polls

a. Create Poll → POST /polls (Auth required)
    {
        "question": "What is your favorite language?",
        "options": ["JavaScript", "Python", "C++"]
    }


b. Get All Polls → GET /polls

c. Get Poll by ID → GET /polls/:id

Votes

# Vote on Poll → POST /votes/:id/vote (Auth required)
    {
        "optionId": 2
    }

WebSocket Usage (Real-Time Updates)

- Connect
    ws://localhost:3000

- Events
    - joinPoll → Join a poll room
    socket.emit("joinPoll", 1); // 1 = pollId


- pollUpdated → Receive updated poll results automatically
    socket.on("pollUpdated", (data) => {
        console.log("Updated Results:", data);
    });

Testing Guide

1. Open Postman and test:
    - Register/Login
    - Create Poll
    - Vote on Poll
    - Fetch Polls

2. Open Socket.IO Tester (online):
    - Connect to ws://localhost:3000
    - Send:
        ["joinPoll", 1]

    - Cast a vote in Postman → See live updates appear.

Features

- User authentication with JWT
- Create polls with multiple options
- Cast votes with validation (no duplicate votes)
- Fetch polls & results
- Real-time updates with WebSocket

Submission Notes

- Make sure PostgreSQL is running locally.
- Use npx prisma migrate dev before starting the server.
- WebSocket events tested via Socket.IO Tester.