B12J - Online Judge Platform

B12J is a comprehensive online judge platform designed for hosting programming contests and practicing problem-solving. It provides a robust environment for users to submit solutions, get them judged, and participate in contests.

Features

• Contest Management:
  • Create and manage programming contests with specified start and end times.
  • Add problems to contests with individual scoring and time limits.
  • Define writers and testers for contests.
• Problem Management:
  • Create and manage a library of programming problems.
  • Support for multiple programming languages (C/C++, Python, TypeScript, Kotlin).
  • Define time and memory limits for each problem.
  • Add test cases with input and expected output.
  • Option to include a checker function for custom validation.
• Submission System:
  • Users can submit solutions to problems in various languages.
  • Real-time judging of submissions with verdicts like Accepted (AC), Wrong Answer (WA), Time Limit Exceeded (TLE), etc.
  • Detailed submission history for users.
• User Authentication:
  • User registration and login.
  • Google OAuth for quick and secure login.
  • JWT-based authentication for API access.
• Real-time Updates:
  • WebSockets for real-time updates on contest standings, new submissions, and problem discussions.
• Tutorials and Discussions:
  • Create tutorials for problems.
  • Comment section for discussions on problems.
• Standings:
  • Live contest standings.
  • Separate standings for during and after the contest.
• Admin Interface:
  • Django admin panel for managing users, contests, problems, and other platform data.
• API:
  • RESTful API for interacting with the platform programmatically.

Usage

Prerequisites

• Python 3.12.1
• Node.js 16.20.2
• PostgreSQL (or other Django-compatible database)
• Judge0 for code execution (can be self-hosted or a cloud instance)

Setup

1. Clone the repository:

   git clone <repository-url>
   cd b12j

2. Backend Setup:
   • Create and activate a Python virtual environment:

     python -m venv venv
     source venv/bin/activate  # On Windows: venv\Scripts\activate

   • Install Python dependencies:

     pip install -r requirements.txt

   • Configure database settings in b12j/settings.py.
   • Set up environment variables for Judge0 URL and API Key, Firebase Admin SDK, etc. (refer to .env.example if provided, or create one).
   • Run database migrations:

     python manage.py migrate

   • Create a superuser:

     python manage.py createsuperuser

3. Frontend Setup:
   • Navigate to the frontend directory:

     cd b12j-front

   • Install Node.js dependencies:

     npm install

4. Running the Application:
   • Backend (Development):

     python manage.py runserver

     The Django development server will typically run on http://127.0.0.1:8000/.
   • Frontend (Development): In the b12j-front directory:

     npm start

     The React development server will typically run on http://localhost:3000/.
   • Production: The Procfile suggests using Daphne for ASGI applications:

     web: daphne b12j.asgi:application --port $PORT --bind 0.0.0.0 -v2
     

     For the frontend, build the static assets:

     cd b12j-front
     npm run build

     Configure your web server (e.g., Nginx) to serve the Django backend and the static frontend files from b12j-front/build/.

API Endpoints

The platform exposes a RESTful API for various functionalities. Key API endpoints are managed under the /api/ path.

• Authentication:
  • api/auth/jwt/create/: Obtain JWT token.
  • api/auth/o/complete/<provider>/: OAuth completion (e.g., Google).
  • api/auth/google/token/: Google login.
  • api/auth/users/: User management (Djoser).
• Contests: api/contests/
• Problems: api/problems/
• Submissions: api/submissions/
• Comments: api/problems/<problem_id>/comments/
• Tutorials: api/tutorials/
• Test Cases: api/test-cases/
• Users: api/users/ (Read-only user information)
• Standings: api/standing/<contest_id>

Refer to api/urls.py for a detailed list of all available API routes.

Technical Details

Backend

• Framework: Django (Python)
• API: Django REST framework
• Real-time Communication: Django Channels (WebSockets)
• Authentication: Djoser (for JWT), Social Auth App Django (for OAuth)
• Database: Configured for PostgreSQL (using djongo in requirements.txt suggests potential MongoDB experimentation, but Django's ORM primarily targets SQL databases. The project structure indicates a relational DB focus).
• Code Judging: Integrates with Judge0 API for secure code execution and evaluation.
• Asynchronous Tasks: Django Channels for background tasks like judging submissions.

Frontend

• Framework: React.js
• State Management: Redux (with @reduxjs/toolkit)
• Routing: React Router
• HTTP Client: Axios
• UI Components:
  • Quill for rich text editing.
  • React Ace for code editor.
  • React Select for enhanced select inputs.
• Form Handling: React Hook Form with Joi/Zod for validation.
• Styling: CSS, Bootstrap.
• Build Tool: Create React App (react-scripts)

Key Modules/Apps

• api/: Handles all REST API logic.
• judge/: Core logic for contest, problem, submission, and judging.
• users/: User authentication and management.
• ws/: WebSocket consumers and real-time communication logic.
• b12j-front/: React frontend application.

This README provides a high-level overview. For more detailed information, please refer to the source code and specific documentation within each module.