Unlock the Power of LoopBack: A Comprehensive Guide to Building APIs and Microservices
What is LoopBack?
LoopBack is a highly extensible, open-source Node.js and TypeScript framework based on Express that enables you to quickly create APIs and microservices composed from backend systems such as databases and SOAP or REST services. With a strong, ever-growing community, LoopBack is an excellent framework for building APIs and microservices.
The Limitations of Express.js
While Express.js is fast, unopinionated, and minimalist, it lacks most of the functionality that is common in a full-fledged web application framework. As a result, you need to do a lot of decision-making, such as creating the structure that supports your backend and identifying the most appropriate package. With LoopBack, your project has a predefined structure, making it easier to get started.
Building a Book Store Application with LoopBack
In this tutorial, we’ll build a book store application using LoopBack. Our app will implement basic CRUD operations, and we’ll demonstrate how to use LoopBack’s CLI and API explorer.
Bootstrapping Your Application
To bootstrap a LoopBack application, we’ll use the LoopBack CLI. Run the following command to install it:
npm install -g @loopback/cli
Next, create a new project with the CLI tool:
lb4 app
Adding a Book Model
To achieve this, we need to build a model that describes our domain objects (the type of data). LoopBack provides decorators — @model and @property — that make defining models extensible.
Setting up a Datasource
A datasource in LoopBack acts as an interface for connecting to various sources of data, such as a database, REST service, SOAP web service, or gRPC microservice, by providing the necessary configuration properties.
Adding a Book Repository
Now that we have a model and a datasource, we need to create a repository to handle operations of the book model against the underlying datasource.
Adding a Book Controller
In LoopBack, you do this in the Controller class. The controllers handle the request-response lifecycle for your app.
Testing Your App
Run your app with the following command:
npm start
Open http://127.0.0.1:3000/explorer in your browser. You should see the API explorer showing all the defined endpoints for your BookController class.
The Benefits of LoopBack
LoopBack saves you a lot of manual work. Its CLI provides a wide range of commands that can do pretty much anything, from creating models, repositories, and controllers, to configuring a datasource for the application. LoopBack can be used in various scenarios, including CRUD operations (accessing databases) and integrating with other infrastructures and services. Lastly, it’s simple to get started using LoopBack because the learning curve is low.