Build Simple Nodejs API for Microservice

Express Nodejs

In this article we are gonna build Nodejs project for API and next we will integrate services with a gateway, so that is microservice.

This project we will build user service that focus for user management such as login, register and detail user. Steps to build user service are:
- Create Express project
- Install Sequelize
- Create migration
- Create seeder with fake data
- Modify Config
- Modify model
- Create API
- Register to routes
- Run in Postman

Create Express Project

For create a project, you need install Nodejs and Express in your PC. Then, you can use this command

Install Sequelize

Sequelize is a library that make our Nodejs project can using database. It features solid transaction support, relations, eager and lazy loading, read replication and more. You can read more the documentation here. For using Sequelize, you need to install sequelize and sequelize-cli (optional). But i recommend you to install sequelize-cli.

Sequelize CLI

Create Migration

To create migration file, you can use Sequelize CLI. Now we create a migration file for users table with name create_table_users. You can follow this command

Inside create_table_users file, we define the fields of users table.

create table users migration

Create Seeder with Fake Data

Seeder is way to let us insert the initial data to our database, for generate dummy data its called Faker Factory. Next we create a seeder file with name user-seeders.

Inside the file, we will insert dummy data for users table using faker. Because we have password field that need to be encrypted, so we also need bcryptjs for encryption. Here is the user-seeders file.

User Seeder File

Modify Config

To connect our Nodejs with database, we need some configuration in config file. How i config the configuration file are:
- Install dotenv
- Create an .env file, fill the file with PORT, DB_HOST, DB_NAME, DB_USERNAME, DB_PASSWORD variables.
- import dotenv in app.js
- rename config.json to config.js
- convert json code into js code

config.js

Next, you can seed the data by npx sequelize db:seed:all

Modify Models

As default, User Model created already when we install Sequelize into our Nodejs project, so we only need to adjust the field as we declare in migration file.

User Model

Create API

For me, foldering is an important thing. With good folder management its help us to easy to maintain and scale up as well. Here is how i set the folders.

Folder Management for API Nodejs

Inside handler folder we create folder as their focus. In example for user folder, its mean that folder will manage everything about user. Next we will write files inside user folder.

This file is for create a login API only, we will check the email and password from request body with data in database. Will return success or failed depends the credential.

login.js

This file is like a parent file to import all files inside user folder, so when we call the file it will be easier.

index.js

Now we will create a route file for users. The file is users.js inside routes.

users.js

Register to Routes

After we create file routes for users, now we need to register to app.js. Just add a line to add the users routes.

register users routes

Run in Postman

To make sure our API run as expected, we can try in Postman.

Run in Postman

From the steps above we already create APIs with Express Nodejs. You can clone my project from my Github as well. Next, we continue to build Microservice Gateway with Express Nodejs. See you!

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