🚀 GraphQL Task Management Backend

A production-grade backend system that simulates real-world task workflows with role-based access control and approval pipelines.

Unlike basic CRUD apps, this system enforces strict task lifecycle transitions:

PENDING → IN_PROGRESS → COMPLETION_REQUESTED → COMPLETED / REJECTED

Built with GraphQL, PostgreSQL, and Prisma, focusing on backend architecture and business logic design.

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🎯 Problem Solved

Most task management systems are simple CRUD applications.

This project solves:

• Controlled task lifecycle management
• Approval-based workflows
• Role-based authorization
• Preventing invalid state transitions

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🔥 Features

• 🔐 JWT Authentication (Access + Refresh tokens in HTTP-only cookies)

• 👥 Role-based authorization (ADMIN / USER)

• 🧠 Task lifecycle management:

  • PENDING → IN_PROGRESS → COMPLETION_REQUESTED → COMPLETED / REJECTED

• ✅ Admin approval system

• ❌ Rejection with reason tracking

• 🚫 Duplicate request prevention

• 🗂 Modular architecture (Resolvers, Middleware, Context)

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🛠 Tech Stack

• Node.js
• Express.js
• GraphQL (Apollo Server)
• PostgreSQL
• Prisma ORM
• JWT Authentication

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🧠 Architecture Overview

• Context-based authentication

• Resolver separation:

  • Auth
  • Task
  • TaskRequest

• Prisma for relational data modeling

• Middleware for request-level validation

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🧪 API Testing

Use Postman collection included in repo:

• Login
• Assign task
• Start task
• Request completion
• Approve / Reject

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📡 Sample GraphQL Operations

Assign Task (Admin)

mutation {
  assignTask(title: "Task A", userIds: [3]) {
    id
    title
    status
  }
}

Start Task (User)

mutation {
  startTask(taskId: 1) {
    id
    status
  }
}

Request Completion

mutation {
  requestCompletion(taskId: 1) {
    task { status }
    request { status }
  }
}

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⚙️ Setup Instructions

1. Clone the repository

git clone <repo-url>

1. Install dependencies

npm install

1. Create .env

DATABASE_URL=your_db_url
JWT_SECRET=your_secret

1. Run database

npx prisma db push

1. Start server

node src/index.js

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🎯 Future Improvements

• Add database transactions for atomic operations
• Add pagination & filtering
• Add rate limiting
• Add GraphQL subscriptions
• Build frontend (React / Next.js)

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🧠 Engineering Highlights

• Context-based authentication using cookies
• Separation of concerns (Resolvers, Middleware, Context)
• Prisma relational schema design
• Duplicate request prevention logic
• State-driven workflow implementation

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👨‍💻 Author

Biswayan Paul