Phaint Backend

A real-time collaborative drawing application backend built with Go, Firebase, and WebSockets.

Overview

Phaint is a collaborative digital canvas platform that allows multiple users to create, edit, and share drawing projects in real-time. This backend handles user authentication, project management, real-time collaboration through WebSockets, and persistent storage using Firebase.

Features

🎨 Real-time Collaboration

• Multi-user canvas editing with live cursor tracking
• Real-time synchronization of drawing operations
• User presence indicators with color-coded cursors
• WebSocket-based communication for low-latency updates

👥 User Management

• User registration and authentication via Firebase Auth
• Email/password authentication
• User profile management

📁 Project Management

• Create and manage drawing projects
• Project collaboration with invite system
• Canvas-based project organization
• Persistent project data storage

🎯 Vector Graphics Support

• Multiple drawing tools (paths, rectangles, circles)
• Customizable stroke properties and fills
• Interactive elements with action support
• Canvas background customization

Architecture

Core Components

• WebSocket Handler: Manages real-time connections and broadcasts
• Canvas Service: Thread-safe canvas and vector element management
• Firebase Integration: Authentication and data persistence
• Project System: Multi-canvas project organization
• Invitation System: Secure project sharing

Data Models

• Canvas: Individual drawing surfaces with vector data
• VectorElements: Paths, rectangles, and circles with properties
• Projects: Collections of canvases with metadata
• Users: Authentication and profile information

Configuration

Environment Setup

Create config/secrets/config.yaml:

firebase:
  database_url: "your-firebase-database-url"
  credential_path: "\\config\\secrets\\firebase-credentials.json"
  web_api_key: "your-firebase-web-api-key"

Firebase Setup

1. Create a Firebase project
2. Enable Firestore Database
3. Enable Authentication with Email/Password
4. Download service account credentials
5. Place credentials in config/secrets/firebase-credentials.json

Collections Structure

users

{
  "UID": "string",
  "mail": "string", 
  "username": "string"
}

projects

{
  "UID": "string",
  "PID": "string",
  "ProjectName": "string",
  "CreationDate": "string",
  "Collaborators": ["string"],
  "CanvasesData": [Canvas]
}

invitations

{
  "CreatorUID": "string",
  "Link": "string",
  "ProjectID": "string",
  "Used": boolean
}

Installation & Setup

Prerequisites

• Go 1.19+
• Firebase project with Firestore enabled
• Firebase service account credentials

Installation

1. Clone the repository:

git clone <repository-url>
cd phaint_be

2. Install dependencies:

go mod tidy

3. Set up configuration files (see Configuration section)

4. Run the application:

go run main.go

The server will start on port 8080.

Development

Project Structure

phaint_be/
├── config/             # Configuration management
├── internal/
│   ├── handlers/      # HTTP and WebSocket handlers
│   ├── services/      # Business logic services
│   └── utils/         # Utility functions
├── models/            # Data models
└── main.go           # Application entry point

Contributing

1. Fork the repository
2. Create a feature branch
3. Implement changes with tests
4. Submit a pull request

Support

For issues and questions, please open an issue on the repository or contact the development team.