GraphQL Demo Project

Overview

This project is a demo application built with Spring Boot, GraphQL, and Java. It showcases the integration of GraphQL APIs with a backend service for managing inventory items.

Features

• GraphQL API:
  • Queries to fetch inventory items.
  • Mutations to add new inventory items.
  • Subscriptions for real-time updates on inventory items.
• Reactive Programming:
  • Utilizes Reactor for handling subscriptions and real-time updates.

Technologies Used

• Java 17
• Spring Boot 3.4.5
• GraphQL
• Reactor
• Maven

Project Structure

• src/main/java: Contains the main application code.
  • controller: Handles GraphQL queries, mutations, and subscriptions.
  • entities: Defines the InventoryItem entity.
  • service: Contains business logic for inventory management.
  • util: Includes utility classes like InventoryPublisher.
• src/main/resources/graphql: Contains GraphQL schema files.
• src/test/java: Includes unit tests for the application.

Setup Instructions

1. Prerequisites:
   • Java 17 or higher.
   • Maven installed.
2. Clone the Repository:

   git clone https://github.com/ibrahimnadra/GraphQLDemo.git
   cd GraphQLDemo

3. Update Configuration:
   • Ensure you have a MySQL database running.
   • Create a schema for the application.
   • Update the database connection properties in application.properties:

   • spring.datasource.url=jdbc:mysql://localhost:3306/your_database_name
     spring.datasource.username=your_username
     spring.datasource.password=your_password

4. Build the Project:

   ./mvnw clean install

5. Run the Application:

   ./mvnw spring-boot:run

6. Access GraphQL Playground:
   • Navigate to http://localhost:8080/graphql.

GraphQL Schema

The GraphQL schema defines the following types:

• InventoryItem: Represents an inventory item with fields like id, name, category, supplier, costPrice, sellingPrice, and quantity.
• Query: Fetch inventory items or a specific item by ID.
• Mutation: Add new inventory items.
• Subscription: Listen for real-time updates on inventory items.

Testing

• Unit tests are written using JUnit and Reactor Test.
• Run tests with:

  ./mvnw test

Testing with a Third-Party Client Using Postman:

1. Open Postman and click on create from my workspace section.
2. Select the GraphQL option.
3. Enter the GraphQL endpoint URL: http://localhost:8080/graphql.
4. Under the Schema tab, you can import the GraphQL schema file located at src/main/resources/graphql/inventory.graphqls in the project directory to get auto-completion and documentation support.
5. Under the Query tab, you can see all the method which are imported from the schema, under the related operation (query, mutation, subscription).
6. Check the schema method you want to test, for example, addInventoryItem and fill in the required argument fields.
7. Check the fields you want to return in the response.
8. Finally click on the Query button to execute the request and view the response.
9. For subscription, create new request and see the real time updates on adding new inventory items.

Mutation Request

Subscription Request