Subspace Chat Application Backend

Subspace is a simple chat application backend built with PHP and the Slim framework. It allows users to create chat groups, join groups, send messages, and list messages within a group.

Features

• Create chat groups
• Join existing chat groups
• Send messages to groups
• List messages in a group
• SQLite database for data storage
• RESTful JSON API

Requirements

• PHP 7.4 or newer
• Composer
• SQLite 3

Installation

1. Clone the repository:

   git clone https://github.com/sencerburak/subspace-backend.git
   cd subspace-backend
   

2. Install dependencies:

   composer install
   

3. Set up the environment:

   cp .env.example .env
   

   Edit the .env file and set the appropriate values for your environment.

4. Initialize the database:

   php db_setup.php
   

5. Start the PHP development server:

   composer start
   

The application should now be running at http://localhost:8080.

Architecture

The application follows a layered architecture to separate concerns and improve maintainability:

1. Routing Layer: Implemented using Slim framework, defining API endpoints and HTTP methods.
2. Controller Layer: Handles incoming requests, processes data, and returns responses.
3. Service Layer: Contains business logic, orchestrates operations between repositories.
4. Repository Layer: Manages data persistence and retrieval from the SQLite database.
5. Model Layer: Defines data structures and entities used throughout the application.

Key Components

1. User Management: Users are identified by a unique ID, which is used as a simple authentication mechanism for API requests.

2. Chat Groups: Public groups that any user can create or join. Groups are identified by a unique ID.

3. Messaging: Users can send messages within groups they've joined. Messages are associated with a user and a group.

4. Database: SQLite is used for simplicity and ease of setup. The database schema includes tables for users, chat_groups, user_group associations, and messages.

5. API Endpoints:

   • POST /users: Create a new user
   • GET /users: List all users
   • GET /users/{id}: Get a specific user
   • POST /chat-groups: Create a new chat group
   • GET /chat-groups: List all chat groups
   • POST /chat-groups/{id}/join: Join a chat group
   • POST /chat-groups/{id}/messages: Send a message to a group
   • GET /chat-groups/{id}/messages: List messages in a group

   All endpoints that require user identification should include a User-Id header in the request.

6. Testing: PHPUnit is used for unit and integration testing, ensuring the reliability and correctness of the implemented features.

API Usage - Example Curl Commands

Users

Create a new user

curl -X POST http://localhost:8080/users \
  -H "Content-Type: application/json" \
  -d '{"username": "johndoe"}'

List all users

curl -X GET http://localhost:8080/users \
  -H "User-Id: 1"

Get a specific user

curl -X GET http://localhost:8080/users/1 \
  -H "User-Id: 1"

Chat Groups

Create a new chat group

curl -X POST http://localhost:8080/chat-groups \
  -H "Content-Type: application/json" \
  -H "User-Id: 1" \
  -d '{"name": "General Chat"}'

List all chat groups

curl -X GET http://localhost:8080/chat-groups \
  -H "User-Id: 1"

Join a chat group

curl -X POST http://localhost:8080/chat-groups/1/join \
  -H "User-Id: 1"

Messages

Send a message to a group

curl -X POST http://localhost:8080/chat-groups/1/messages \
  -H "Content-Type: application/json" \
  -H "User-Id: 1" \
  -d '{"content": "Hello, everyone!"}'

List messages in a group

curl -X GET http://localhost:8080/chat-groups/1/messages \
  -H "User-Id: 1"

Note: Replace localhost:8080 with the appropriate host and port if your server is running on a different address. Also, make sure to replace the User-Id with a valid user ID when making requests.

Testing

To run the test suite, use the following command:

composer test