@gasket/plugin-express

Adds Express to your application.

Guides

• Setup Guide for adding middleware and routes.
• Common "Gotchas" encountered with Express middleware.

Installation

New apps

gasket create <app-name> --plugins @gasket/plugin-express

Existing apps

npm i @gasket/plugin-express

Modify plugins section of your gasket.config.js:

module.exports = {
  plugins: {
    add: [
+      '@gasket/plugin-express'
    ]
  }
}

Configuration

All the configurations for the plugin are added under express in the config:

• compression: true by default. Can be set to false if applying compression differently.
• excludedRoutesRegex: (deprecated) renamed to more correct middlewareInclusionRegex.
• middlewareInclusionRegex: RegExp filter to apply toward request URLs to determine when Gasket middleware will run. You can use negative lookahead patterns to exclude routes like static resource paths.
• routes: Glob pattern for source files exporting route-defining functions. These functions will be passed the express app object, and therein they can attach handlers and middleware.
• 'trustProxy': Enable trust proxy option, see Express documentation on Express behind proxies

Example configuration

module.exports = {
  plugins: {
    add: ['@gasket/express']
  },
  express: {
    compression: false,
    routes: 'api/*.js',
    middlewareInclusionRegex: /^(?!\/_next\/)/,
    trustProxy: true
  }
}

Middleware paths

The gasket.config.js can contain a middleware property, which is an array of objects that map plugins to route or path patterns, allowing apps to tune which middleware are triggered for which requests.

  middleware: [
    {
      plugin:'gasket-plugin-example', // Name of the Gasket plugin
      paths: ['/api']
    },
    {
      plugin:'@some/gasket-plugin-example',
      paths: [/\/default/]
    },
    {
      plugin: '@another/gasket-plugin-example',
      paths: ['/proxy', /\/home/]
    }
  ]

Lifecycles

middleware

Executed when the express server has been created, it will apply all returned functions as middleware.

module.exports = {
  hooks: {
    /**
    * Add Express middleware
    *
    * @param {Gasket} gasket The Gasket API
    * @param {Express} app - Express app instance
    * @returns {function|function[]} middleware(s)
    */
    middleware: function (gasket, app) {
      return require('x-xss-protection')();
    }
  }
}

You may also return an Array to inject more than one middleware.

express

Executed after the middleware event for when you need full control over the express instance.

module.exports = {
  hooks: {
    /**
    * Update Express app instance
    *
    * @param {Gasket} gasket The Gasket API
    * @param {Express} express Express app instance
    * @returns {function|function[]} middleware(s)
    */
    express: async function (gasket, express) {
    }
  }
}

errorMiddleware

Executed after the express event. All middleware functions returned from this hook will be applied to Express.

module.exports = {
  hooks: {
    /**
    * Add Express error middlewares
    *
    * @param {Gasket} gasket The Gasket API
    * @returns {function|function[]} error middleware(s)
    */
    errorMiddleware: function (gasket) {
    }
  }
}

How it works

This plugins hooks the createServers lifecycles from @gasket/plugin-https.

License

MIT