Chat Application

This is a simple chat application API built in Java using the Spring Boot Framework. It allows users to create groups, join them, and exchange messages within the groups. The application is structured as a RESTful API, using a MySQL database and is tested using JUnit.

The application supports the following core features:

• User Management: Create and list users.
• Group Management: Create groups, join groups, and list groups.
• Messaging: Send and retrieve messages in groups.

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Frameworks and Tools Used

• Spring Boot: Used as the primary framework for creating RESTful APIs.
• Hibernate (JPA): Manages database interaction with entities and repositories. Relationships between entities such as @OneToMany and @ManyToMany are used to model the data.
• MySQL Database: A database used for development.
• Docker: Used for containerizing and running the application along with the database.

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Testing Setup

The testing environment uses the following:

• H2 Database: The in-memory database is configured for the test profile to isolate tests from the development database.
• JUnit 5: For creating and running test cases.
• MockMvc: Provides a way to test the REST API endpoints by simulating HTTP

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Steps to Run

1. Build the Project with Maven

   • Open a terminal and navigate to the project directory.
   • Run the following command to build the project:

     mvn clean install

2. Run the Application with Docker

   • In the terminal, execute:

     docker-compose up --build

   • This will start the application along with a PostgreSQL database in Docker containers.

3. Access the Application

   • The application will be available at:

     http://localhost:8080
     

   • Verify the application by accessing the /health endpoint:

     http://localhost:8080/health
     

4. Testing API Endpoints

   • Use the Postman collection provided in the project folder to test the APIs.

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Database Schema

User Table

Column	Type	Constraints
id	BIGINT	Primary Key
name	VARCHAR	Not Null
email	VARCHAR	Not Null, Unique

Group Table

Column	Type	Constraints
id	BIGINT	Primary Key
name	VARCHAR	Not Null, Unique

Message Table

Column	Type	Constraints
id	BIGINT	Primary Key
group_id	BIGINT	Foreign Key to Group
user_id	BIGINT	Foreign Key to User
content	TEXT	Not Null

Group Participants Table

Column	Type	Constraints
group_id	BIGINT	Foreign Key to group.id
user_id	BIGINT	Foreign Key to user.id

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API Endpoints

Method	Route	Description	Request Body	Query Parameters
GET	/user/list	List all users	None	None
POST	/user/create	Create a new user	{ "name": "User Name", "email": "User Email" }	None
POST	/groups/create	Create a new group	{ "name": "Group Name" }	None
POST	/groups/join/{group_id}	Join an existing group	{ "user_id": "User ID" }	None
GET	/groups/list	List all available groups	None	{ "user_id": "User ID"}
POST	/messages/send/{group_id}	Send a message in a group	{ "user_id": "User ID", "message": "Message content" }	None
GET	/messages/list/{group_id}	List all messages in a group	None	{ "user_id": "User ID"}
GET	/messages/unread/{group_id}	List unread messages in a group	None	{ "user_id": "User ID" }