This content originally appeared on DEV Community and was authored by Rahul kumar
Agenda :
Building a rest api using Nest.JS .
Backend Architecture :
Technologies used:
- Node.js --- Platform .
- NestJS --- server .
- TypeORM --- orm .
- PostgreSQL --- database .
What is Node.js :
NodeJS is a Javascript runtime(contains everything to run javascript) for building server side applications .
What is NestJs :
Nest is a framework for building efficient and scalable NodeJs server side applications .
What is TypeORM :
TypeORM is an object relational mapper which task is to basically generates objects using object oriented programming which maps to the database virtually .
What is PostgreSQL :
PostgreSQL is an object relational database management system for building scalable and high availability applications .
- Install @nestjs/cli package .and create a new project
$ npm i -g @nestjs/cli
$ nest new project-name
In a common nestJS project :
- main.ts contains the bootstraping code .
- .spec file contains the testing files .
- nestjs usages module to organize the application structure .
- controller contains the routing rules for the application .
- service contains the business logic for the application .
$ npm run start
curl localhost:3000
Set up Database :
$sudo -U postgres
$psql
$create database conduit
$create user conduit with encrypted password conduit
$grant all privileges on database conduit to conduit
- File structure :
src
|- app.controller.ts
|- app.controller.spec.ts
|- app.module.ts
|- app.service.ts
|- main.ts
Create a connection to the database .
$ touch app.dbconfig.ts
import {TypeOrmModuleOptions} from "typeorm";
export function createTypeOrmProdConfig(): TypeOrmModuleOptions{
return({
type: "postgres",
username: "conduit",
password: "conduit",
database: "conduit"
entities: [join(__dirname, '**', '*.entity.{ts, js}')],
synchronize: true,
logging: true,
logger: "advanced-console",
});
}
- Next we have to create the
entitiesfor our Database . And the individual entity to the entities array in thecreateConnectionfunction .
$ mkdir src/entities
$cd entities
$nano Article.ts
@Entity()
export class Article {
@PrimaryColumn({length: 40})
slug: string
@Column({length: 40})
title?: string
@Column({length: 100, nullable:true})
description: string
@Column({type: 'text'})
body: string
Generate module, service, controller for the article route :
nest g mo article module
nest g co article module
nest g s article module
$ cd module/article
$ nano module.article.ts
imports : [Typeormmodue.forFeature([Article])]
- navigate to the article service file .
@InjectRepository(Article) private readonly articleRepo: Repository<Article>,
async getAllArticles(): Promise<Article[]> {
return await this.articleRepo.find();
}
- navigate to the article controller file .
constructor(private readonly articlesService: ArticlesService) {}
@Get()
async getAllArticles(): Promise<Article[]> {
return await this.articlesService.getAllArticles();
}
Then finally in the application root module .
imports :[TypeOrmModule.forroot([Article])]
$npm start
Thank You For Reading ?
This content originally appeared on DEV Community and was authored by Rahul kumar
Rahul kumar | Sciencx (2021-06-08T04:30:53+00:00) nest.js + TypeORM + PostgreSQL. Retrieved from https://www.scien.cx/2021/06/08/nest-js-typeorm-postgresql/
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