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@loopback/boot

A convention based project Bootstrapper and Booters for LoopBack Applications

Overview

A Booter is a Class that can be bound to an Application and is called to perform a task before the Application is started. A Booter may have multiple phases to complete its task. The task for a convention based Booter is to discover and bind Artifacts (Controllers, Repositories, Models, etc.).

An example task of a Booter may be to discover and bind all artifacts of a given type.

A Bootstrapper is needed to manage the Booters and execute them. This is provided in this package. For ease of use, everything needed is packages using a BootMixin. This Mixin will add convenience methods such as boot and booter, as well as properties needed for Bootstrapper such as projectRoot. The Mixin also adds the BootComponent to your Application which binds the Bootstrapper and default Booters made available by this package.

Installation

$ npm i @loopback/boot

Basic Use

import {Application} from '@loopback/core';
import {BootMixin, Booter, Binding} from '@loopback/boot';
class BootApp extends BootMixin(Application) {}

const app = new BootApp();
app.projectRoot = __dirname;

await app.boot();
await app.start();

BootOptions

List of Options available on BootOptions Object.

Option Type Description
controllers ArtifactOptions ControllerBooter convention options
repositories ArtifactOptions RepositoryBooter convention options
datasources ArtifactOptions DataSourceBooter convention options
services ArtifactOptions ServiceBooter convention options

ArtifactOptions

Options Type Description
dirs string \| string[] Paths relative to projectRoot to look in for Artifact
extensions string \| string[] File extensions to match for Artifact
nested boolean Look in nested directories in dirs for Artifact
glob string A glob pattern string. This takes precedence over above 3 options (which are used to make a glob pattern).

BootExecOptions

Experimental support. May be removed or changed in a non-compatible way in future without warning

To use BootExecOptions you must directly call bootstrapper.boot() and pass in BootExecOptions. app.boot() provided by BootMixin does not take any paramters.

const bootstrapper: Bootstrapper = await this.get(
  BootBindings.BOOTSTRAPPER_KEY,
);
const execOptions: BootExecOptions = {
  booters: [MyBooter1, MyBooter2],
  filter: {
    phases: ['configure', 'discover'],
  },
};

const ctx = bootstrapper.boot(execOptions);

You can pass in the BootExecOptions object with the following properties:

Property Type Description
booters Constructor<Booter>[] Array of Booters to bind before running boot()
filter.booters string[] Names of Booter classes that should be run
filter.phases string[] Names of Booter phases to run

Available Booters

ControllerBooter

Description

Discovers and binds Controller Classes using app.controller().

Options

The options for this can be passed via BootOptions when calling app.boot(options: BootOptions).

The options for this are passed in a controllers object on BootOptions.

Available options on the controllers object on BootOptions are as follows:

Options Type Default Description
dirs string \| string[] ['controllers'] Paths relative to projectRoot to look in for Controller artifacts
extensions string \| string[] ['.controller.js'] File extensions to match for Controller artifacts
nested boolean true Look in nested directories in dirs for Controller artifacts
glob string   A glob pattern string. This takes precendence over above 3 options (which are used to make a glob pattern).

RepositoryBooter

Description

Discovers and binds Repository Classes using app.repository() (Application must use RepositoryMixin from @loopback/repository).

Options

The options for this can be passed via BootOptions when calling app.boot(options: BootOptions).

The options for this are passed in a repositories object on BootOptions.

Available options on the repositories object on BootOptions are as follows:

Options Type Default Description
dirs string \| string[] ['repositories'] Paths relative to projectRoot to look in for Repository artifacts
extensions string \| string[] ['.repository.js'] File extensions to match for Repository artifacts
nested boolean true Look in nested directories in dirs for Repository artifacts
glob string   A glob pattern string. This takes precedence over above 3 options (which are used to make a glob pattern).

DataSourceBooter

Description

Discovers and binds DataSource Classes using app.dataSource() (Application must use RepositoryMixin from @loopback/repository).

Options

The options for this can be passed via BootOptions when calling app.boot(options: BootOptions).

The options for this are passed in a datasources object on BootOptions.

Available options on the datasources object on BootOptions are as follows:

Options Type Default Description
dirs string \| string[] ['datasources'] Paths relative to projectRoot to look in for DataSource artifacts
extensions string \| string[] ['.datasource.js'] File extensions to match for DataSource artifacts
nested boolean true Look in nested directories in dirs for DataSource artifacts
glob string   A glob pattern string. This takes precedence over above 3 options (which are used to make a glob pattern).

ServiceBooter

Description

Discovers and binds Service providers using app.serviceProvider() (Application must use ServiceMixin from @loopback/service-proxy).

IMPORTANT: For a class to be recognized by ServiceBooter as a service provider, its name must end with Provider suffix and its prototype must have a value() method.

Options

The options for this can be passed via BootOptions when calling app.boot(options: BootOptions).

The options for this are passed in a services object on BootOptions.

Available options on the services object on BootOptions are as follows:

Options Type Default Description
dirs string \| string[] ['repositories'] Paths relative to projectRoot to look in for Service artifacts
extensions string \| string[] ['.repository.js'] File extensions to match for Service artifacts
nested boolean true Look in nested directories in dirs for Service artifacts
glob string   A glob pattern string. This takes precedence over above 3 options (which are used to make a glob pattern).

Contributions

Tests

Run npm test from the root folder.

Contributors

See all contributors.

License

MIT