Honorato-Dev / devshop-api

API model for E_COMMERCE made in Nest JS decoupled from frontend using TYPE ORM and GRAPHQL to relate with POSTGRESSQL database

DevShop

Nest.js API with PostgreSQL and GraphQL

Overview

This technical description outlines the architecture and functionality of a system built with Nest.js, PostgreSQL, and GraphQL.

System Components

1. Environment Setup:

   • Nest.js is chosen for its TypeScript support, dependency injection, and modular architecture.
   • PostgreSQL is selected as the database system due to its reliability and performance.

2. Database Configuration:

   • The application connects to PostgreSQL using TypeORM, an ORM library for TypeScript and JavaScript.
   • TypeORM is used to define entities (data models) using TypeScript classes and map them to database tables.

3. Data Models:

   • TypeScript classes represent data models, each corresponding to a table in the PostgreSQL database.
   • These classes define the structure of data and any associated business logic.

4. GraphQL Integration:

   • Nest.js integrates GraphQL using the @nestjs/graphql module.
   • GraphQL resolvers handle incoming queries and mutations, interacting with services to perform CRUD operations.

5. Services:

   • Nest.js services encapsulate business logic and interact with the database through TypeORM entities.
   • Services provide methods for creating, reading, updating, and deleting data.

6. Data Validation:

   • Data validation is performed using the class-validator library.
   • Decorators are added to entity properties to define validation rules, ensuring data integrity.

7. GraphQL Schema:

   • GraphQL types represent data structures and operations exposed by the API.
   • The schema maps GraphQL types to resolvers, enabling data retrieval and manipulation.

8. Authentication and Authorization (Optional):

   • Middleware can be added to authenticate and authorize GraphQL requests.
   • Libraries like Passport.js handle authentication strategies like JWT or OAuth.

9. Testing:

   • Unit tests are written for services and resolvers using Jest or Mocha.
   • Integration tests verify the system behavior, including interactions with the database and GraphQL layer.

10. Documentation and Tooling:

    • API documentation is generated using tools like GraphQL Playground or Swagger.
    • Examples and explanations are provided for each query and mutation to assist developers.

11. Deployment:

    • The application is prepared for production deployment, including environment configuration and code optimization.
    • Security measures are implemented to protect against common vulnerabilities.

Conclusion

This system architecture leverages the strengths of Nest.js, PostgreSQL, and GraphQL to create a robust and scalable API for managing data.

Installation

$ npm install

Running the app

# development
$ npm run start

# watch mode
$ npm run start:dev

# production mode
$ npm run start:prod

Test

# unit tests
$ npm run test

# e2e tests
$ npm run test:e2e

# test coverage
$ npm run test:cov

Database Migrations

# Script in package.json
"typeorm": "typeorm-ts-node-esm -d ./ormconfig.ts"

# Generate a new migration and synchronizing entities
$ npm run typeorm -- migration:generate ./src/migrations/Initial

# sync database runnig migrations
$ npm run typeorm migration:run

Contributing

If you'd like to contribute to this project, please fork the repository and submit a pull request. You can also open an issue if you have any questions or suggestions.

License

Nest is MIT licensed.