Service providers

Services providers are plain JavaScript classes with lifecycle methods to perform actions during different phases of the application.

A service provider can register bindings into the container, extend existing bindings, or run actions after the HTTP server starts.

Service providers are the entry point to an AdonisJS application with the ability to modify the application state before it is considered ready. It is mainly used by external packages to hook into the application lifecycle.

The providers are registered inside the adonisrc.ts file under the providers array. The value is a function to lazily import the service provider

{
  providers: [
    () => import('@adonisjs/core/providers/app_provider'),
    () => import('./providers/app_provider.js'),
  ]
}

By default, a provider is loaded in all the runtime environments. However, you can limit the provider to run in specific environments.

{
  providers: [
    () => import('@adonisjs/core/providers/app_provider'),
    {
      file: () => import('./providers/app_provider.js'),
      environment: ['web', 'repl']
    }
  ]
}

Writing service providers

Service providers are stored inside the providers directory of your app. Alternatively, you can use the node ace make:provider app command.

The provider module must have an export default statement returning the provider class. The class constructor receives an instance of the Application class.

See also: Make provider command

import { ApplicationService } from '@adonisjs/core/types'

export default class AppProvider {
  constructor(protected app: ApplicationService) {
  }
}

Following are the lifecycle methods you can implement to perform different actions.

export default class AppProvider {
  register() {
  }
  
  async boot() {
  }
  
  async start() {
  }
  
  async ready() {
  }
  
  async shutdown() {
  }
}

register

The register method is called after an instance of the provider class is created. The register method can register bindings within the IoC container.

The register method is synchronous, so you cannot use Promises inside this method.

export default class AppProvider {
  register() {
    this.app.container.bind('db', () => {
      return new Database()
    })
  }
}

boot

The boot method is called after all the bindings have been registered with the IoC container. Inside this method, you can resolve bindings from the container to extend/mutate them.

export default class AppProvider {
  async boot() {
   const validator = await this.app.container.make('validator')
    
   // Add custom validation rules
   validator.rule('foo', () => {})
  }
}

It is a good practice to extend bindings when they are resolved from the container. For example, you can use the resolving hook to add custom rules to the validator.

async boot() {
  this.app.container.resolving('validator', (validator) => {
    validator.rule('foo', () => {})
  })
}

start

The start method is called after the boot and before the ready method. It allows you to perform actions that the ready hook actions might need.

ready

The ready method gets called at different stages based on the application's environment.

export default class AppProvider {
  async start() {
    if (this.app.getEnvironment() === 'web') {
    }

    if (this.app.getEnvironment() === 'console') {
    }

    if (this.app.getEnvironment() === 'test') {
    }

    if (this.app.getEnvironment() === 'repl') {
    }
  }
}

shutdown

The shutdown method is called when AdonisJS is in the middle of gracefully exiting the application.

The event of exiting the application depends upon the environment in which the app is running and how the application process started. Please read the application lifecycle guide to know more about it.

export default class AppProvider {
  async shutdown() {
    // perform the cleanup
  }
}