LoopBack @ Node.js Leipzig Meetup

LoopBack 4: Build amazing APIs

A platform for building APIs and microservices in Node.js

Björn Strobach - Node.js Meetup Leipzig - July 2019

Who is this guy?

Software Developer @MrAppWare, Magdeburg GitHub: @bstrobach
Twitter: @bstrobach
Xing: http://xing.to/bstrobach

Slides & Code: https://github.com/bstrobach/loopback-nodejs-leipzig

What are we talking about?

LoopBack - What?

LoopBack is a highly extensible, open-source Node.js 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.

LoopBack Docs

Cool, who did it?

StrongLoop
Based in California
Highly active in Node.js Foundation
Published LoopBack in September 2013
~~Acquired by IBM in September 2015 - An IBM Company~~
Since then: LoopBack 3 and 4 released

And why should I use it?

One source of truth

API composition layer

OpenAPI standards

Extensibility

Modern technologies

Nice, tell me more about concepts

Application
Server
Context
Binding
Dependency Injection

~~Controller~~
Interceptors
Route
Sequence
~~Model~~

~~Data Sources~~
~~Repository~~
Relation
Decorator
Component

Controllers?

A class that implements operations defined by an application’s API

Implements an applications business logic

Acts as bridge between the HTTP/REST API and domain/database models

Model?

Describes business domain objects

Usually defines a list of properties with name, type, and other constraints

Can be used for data exchange on the wire or between different systems

Data Sources?

A config for a Connector instance that represents data in an external system

LoopBack supports many different external system, e.g.

In-memory DB, Microsoft SQL, Oracle, Redis, MongoDB, PostgreSQL, ...

Repositories?

Represents a specialized service interface that provides strong-typed data access (for example, CRUD) operations of a domain model against the underlying database or service.

Easy, how can I use it?

Bottom-up

Programmatic, code-first approach, export an OAS

Top-Down

Use the CLI, scaffold application and generate artifacts

CLI? Like the Angular CLI?

Provides CLI tools to help get started quickly
Generates applications and installs their dependencies
Provides optional installation of recommended dependencies
Helps generating artifacts (Controller, DataSource, Model, Repository, [...])

Wow, how can I start developing?

Install LoopBack 4 CLI

                    $ npm i -g @loopback/cli

Create a new LoopBack application

                    $ lb4 app my-app [--yes]

Starting the project

                    $ cd my-app && npm start