fastify-autoload

Convenience plugin for Fastify that loads all plugins found in a directory and automatically configures routes matching the folder structure.

Installation

npm i fastify-autoload

Example

Fastify server that automatically loads in all plugins from the plugins directory:

const fastify = require('fastify')
const autoload = require('fastify-autoload')

const app = fastify()

app.register(autoload, {
  dir: path.join(__dirname, 'plugins')
})

app.listen(3000)

or with ESM syntax:

import autoLoad from 'fastify-autoload'
import { fileURLToPath } from 'url'
import { dirname, join } from 'path'
import fastify from 'fastify'

const __filename = fileURLToPath(import.meta.url)
const __dirname = dirname(__filename)

const app = fastify()

app.register(autoLoad, {
  dir: join(__dirname, 'plugins')
})

app.listen(3000)

Folder structure:

├── plugins
│   ├── hooked-plugin
│   │   ├── autohooks.mjs
│   │   ├── routes.js
│   │   └── children
│   │       ├── commonjs.cjs
│   │       ├── module.mjs
│   │       └── typescript.ts
│   ├── single-plugin
│   │   ├── index.js
│   │   └── utils.js
│   ├── more-plugins
│   │   ├── commonjs.cjs
│   │   ├── module.mjs
│   │   └── typescript.ts
│   └── another-plugin.js
├── package.json
└── app.js

Global Configuration

Autoload can be customised using the following options:

• dir (required) - Base directory containing plugins to be loaded

  Each script file within a directory is treated as a plugin unless the directory contains an index file (e.g. index.js). In that case only the index file (and the potential sub-directories) will be loaded.

  The following script types are supported:

  • .js (CommonJS or ES modules depending on type field of parent package.json)
  • .cjs (CommonJS)
  • .mjs (ES modules)
  • .ts (TypeScript)

• dirNameRoutePrefix (optional) - Default: true. Determines whether routes will be automatically prefixed with the subdirectory name in an autoloaded directory. It can be a sync function that must return a string that will be used as prefix, or it must return false to skip the prefix for the directory.

  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'routes'),
    dirNameRoutePrefix: false // lack of prefix will mean no prefix, instead of directory name
  })
  
  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'routes'),
    dirNameRoutePrefix: function rewrite (folderParent, folderName) {
      if (folderName === 'YELLOW') {
        return 'yellow-submarine'
      }
      if (folderName === 'FoOoO-BaAaR') {
        return false
      }
      return folderName
    }
  })

• ignorePattern (optional) - Regex matching any file that should not be loaded

  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    ignorePattern: /.*(test|spec).js/
  })

• indexPattern (optional) - Regex to override the index.js naming convention

  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    indexPattern: /.*routes(\.ts|\.js|\.cjs|\.mjs)$/
  })

• maxDepth (optional) - Limits the depth at which nested plugins are loaded

  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    maxDepth: 2 // files in `opts.dir` nested more than 2 directories deep will be ignored.
  })

• forceESM (optional) - If set to 'true' it always use await import to load plugins or hooks.

  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    forceESM: true
  })

• options (optional) - Global options object used for all registered plugins

  Any option specified here will override plugin.autoConfig options specified in the plugin itself.

  When setting both options.prefix and plugin.autoPrefix they will be concatenated.

  // index.js
  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    options: { prefix: '/defaultPrefix' }
  })
  
  // /plugins/something.js
  module.exports = function (fastify, opts, next) {
    // your plugin
  }
  
  module.exports.autoPrefix = '/something'
  
  // /plugins/something.mjs
  export default function (f, opts, next) {
    f.get('/', (request, reply) => {
      reply.send({ something: 'else' })
    })
  
    next()
  }
  
  export const autoPrefix = '/prefixed'
  
  // routes can now be added to /defaultPrefix/something

• autoHooks (optional) - Apply hooks from autohooks.js file(s) to plugins found in folder

  Automatic hooks from autohooks files will be encapsulated with plugins. If false, all autohooks.js files will be ignored.

  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    autoHooks: true // apply hooks to routes in this level
  })

  If autoHooks is set, all plugins in the folder will be encapsulated and decorated values will not be exported outside the folder.

• autoHooksPattern (optional) - Regex to override the autohooks naming convention

  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    autoHooks: true,
    autoHooksPattern: /^[_.]?auto_?hooks(\.js|\.cjs|\.mjs)$/i
  })

• cascadeHooks (optional) - If using autoHooks, cascade hooks to all children. Ignored if autoHooks is false.

  Default behaviour of autoHooks is to apply hooks only to the level on which the autohooks.js file is found. Setting cascadeHooks: true will continue applying the hooks to any children.

  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    autoHooks: true, // apply hooks to routes in this level,
    cascadeHooks: true // continue applying hooks to children, starting at this level    
  })

• overwriteHooks (optional) - If using cascadeHooks, cascade will be reset when a new autohooks.js file is encountered. Ignored if autoHooks is false.

  Default behaviour of cascadeHooks is to accumulate hooks as new autohooks.js files are discovered and cascade to children. Setting overwriteHooks: true will start a new hook cascade when new autohooks.js files are encountered.

  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    autoHooks: true, // apply hooks to routes in this level,
    cascadeHooks: true, // continue applying hooks to children, starting at this level,
    overwriteHooks: true // re-start hook cascade when a new `autohooks.js` file is found
  })

• routeParams (optional) - Folders prefixed with _ will be turned into route parameters.

  /*
  ├── routes
  │   └── users
  │       ├── _id
  │       │   └── actions.js
  │       └── index.js
  └── app.js
  */
  
  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'routes'),
    routeParams: true // routes/users/_id/actions.js will be loaded with prefix /users/:id
  })  
  
  // curl http://localhost:3000/users/index
  // { userIndex: [ { id: 7, username: 'example' } ] }
  
  // curl http://localhost:3000/users/7/details
  // { user: { id: 7, username: 'example' } }

Plugin Configuration

Each plugin can be individually configured using the following module properties:

• plugin.autoConfig - Configuration object which will be used as opts parameter

  module.exports = function (fastify, opts, next) {
    console.log(opts.foo) // 'bar'
    next()
  }
  
  module.exports.autoConfig = { foo: 'bar' }

  Or with ESM syntax:

  import plugin from '../lib-plugin.js'
  
  export default async function myPlugin (app, options) {
    app.get('/', async (request, reply) => {
      retrun { hello: options.name }
    })
  }
  export const autoConfig = { name: 'y' }

• plugin.autoPrefix - Set routing prefix for plugin

  module.exports = function (fastify, opts, next) {
    fastify.get('/', (request, reply) => {
      reply.send({ hello: 'world' })
    })
  
    next()
  }
  
  module.exports.autoPrefix = '/something'
  
  // when loaded with autoload, this will be exposed as /something

  Or with ESM syntax:

  export default async function (app, opts) {
    app.get('/', (request, reply) => {
      return { something: 'else' }
    })
  }
  
  export const autoPrefix = '/prefixed'

• plugin.prefixOverride - Override all other prefix options

  // index.js
  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    options: { prefix: '/defaultPrefix' }
  })
  
  // /foo/something.js
  module.exports = function (fastify, opts, next) {
    // your plugin
  }
  
  module.exports.prefixOverride = '/overriddenPrefix'
  
  // this will be exposed as /overriddenPrefix

  Or with ESM syntax:

  export default async function (app, opts) {
    // your plugin
  }
  
  export const prefixOverride = '/overriddenPrefix'

  If you have a plugin in the folder you do not want any prefix applied to, you can set prefixOverride = '':

  // index.js
  fastify.register(autoLoad, {
    dir: path.join(__dirname, 'plugins'),
    options: { prefix: '/defaultPrefix' }
  })
  
  // /foo/something.js
  module.exports = function (fastify, opts, next) {
    // your plugin
  }
  
  // optional
  module.exports.prefixOverride = ''
  
  // routes can now be added without a prefix

• plugin.autoload - Toggle whether the plugin should be loaded

  Example:

  module.exports = function (fastify, opts, next) {
    // your plugin
  }
  
  // optional
  module.exports.autoload = false

• opts.name - Set name of plugin so that it can be referenced as a dependency

• opts.dependencies - Set plugin dependencies to ensure correct load order

  Example:

  // plugins/plugin-a.js
  const fp = require('fastify-plugin')
  
  function plugin (fastify, opts, next) {
    // plugin a
  }
  
  module.exports = fp(plugin, {
    name: 'plugin-a',
    dependencies: ['plugin-b']
  })
  
  // plugins/plugin-b.js
  function plugin (fastify, opts, next) {
    // plugin b
  }
  
  module.exports = fp(plugin, {
    name: 'plugin-b'
  })

  Autohooks:

  The autohooks functionality provides several options for automatically embedding hooks, decorators, etc. to your routes. CJS and ESM autohook formats are supported.

  The default behaviour of autoHooks: true is to encapsulate the autohooks.js plugin with the contents of the folder containing the file. The cascadeHooks: true option encapsulates the hooks with the current folder contents and all subsequent children, with any additional autohooks.js files being applied cumulatively. The overwriteHooks: true option will re-start the cascade any time an autohooks.js file is encountered.

  Plugins and hooks are encapsulated together by folder and registered on the fastify instance which loaded the fastify-autoload plugin. For more information on how encapsulation works in Fastify, see: https://www.fastify.io/docs/latest/Encapsulation/

  Example:

  ├── plugins
  │   ├── hooked-plugin
  │   │   ├── autohooks.js // req.hookOne = 'yes' # CJS syntax
  │   │   ├── routes.js
  │   │   └── children
  │   │       ├── old-routes.js
  │   │       ├── new-routes.js
  │   │       └── grandchildren
  │   │           ├── autohooks.mjs // req.hookTwo = 'yes' # ESM syntax
  │   │           └── routes.mjs
  │   └── standard-plugin
  │       └── routes.js
  └── app.js
  

  // hooked-plugin/autohooks.js
  
  module.exports = async function (app, opts) {
    app.addHook('onRequest', async (req, reply) => {
      req.hookOne = yes;
    });
  }
  
  // hooked-plugin/children/grandchildren/autohooks.mjs
  
  export default async function (app, opts) {
    app.addHook('onRequest', async (req, reply) => {
      req.hookTwo = yes
    })
  }

  # app.js { autoHooks: true }
  
  $ curl http://localhost:3000/standard-plugin/
  {} # no hooks in this folder, so behaviour is unchanged
  
  $ curl http://localhost:3000/hooked-plugin/
  { hookOne: 'yes' }
  
  $ curl http://localhost:3000/hooked-plugin/children/old
  {}
  
  $ curl http://localhost:3000/hooked-plugin/children/new
  {}
  
  $ curl http://localhost:3000/hooked-plugin/children/grandchildren/ 
  { hookTwo: 'yes' }

  # app.js { autoHooks: true, cascadeHooks: true }
  
  $ curl http://localhost:3000/hooked-plugin/
  { hookOne: 'yes' }
  
  $ curl http://localhost:3000/hooked-plugin/children/old
  { hookOne: 'yes' }
  
  $ curl http://localhost:3000/hooked-plugin/children/new
  { hookOne: 'yes' }
  
  $ curl http://localhost:3000/hooked-plugin/children/grandchildren/ 
  { hookOne: 'yes', hookTwo: 'yes' } # hooks are accumulated and applied in ascending order

  # app.js { autoHooks: true, cascadeHooks: true, overwriteHooks: true }
  
  $ curl http://localhost:3000/hooked-plugin/
  { hookOne: 'yes' }
  
  $ curl http://localhost:3000/hooked-plugin/children/old
  { hookOne: 'yes' }
  
  $ curl http://localhost:3000/hooked-plugin/children/new
  { hookOne: 'yes' }
  
  $ curl http://localhost:3000/hooked-plugin/children/grandchildren/ 
  { hookTwo: 'yes' } # new autohooks.js takes over

License

MIT