hops-express

Please see the main Hops Readme for general information and a Getting Started Guide.

This is one of the core presets for Hops and provides the development and production server configuration and mixin infrastructure in order to build a Hops application.

hops-express strives to gracefully handle exceptions and to facilitate infrastructure integration: in case of uncaught middleware errors or upon receiving a SIGTERM signal, the server's close method will be called before exiting the process.

CLI

serve

This command starts an Express.js server with all middleware and configuration applied through the configureServer hook.

Arguments

-p / --production

This is a shortcut for NODE_ENV=production hops serve - it sets the environment variable NODE_ENV to production which enables several performance optimizations for Express.js and its middleware.

You may use either hops serve -p or its equivalent NODE_ENV=production hops serve.

Usage

Configuration

Preset Options

Name	Type	Default	Required	Description
https	Boolean | Object	false	no	Configure HTTPS support for Hops
host	String	[HOST]	no	Specify the IP address that Hops should bind to
port	String	[PORT]	no	Specify the Port that Hops should listen on
distDir	String	'<rootDir>/dist'	no	The folder from which to serve static assets
gracePeriod	number	30000	no	Time to wait (in ms) until killing the server
helmetConfig	Object	{}	no	Headers to set or overwrite in helmet

https

Hops has built in support for HTTPS which can be configured using this setting.

You can set it to true to enable SSL with the included self-signed certificate or you can specify an object with keyFile and certFile that point a proper SSL certificate.

"hops": {
  "https": {
    "keyFile": "./path/to/my.key",
    "certFile": "./path/to/my.cert"
  }
}

host

By default Hops will read an environment variable called $HOST to find the host that the server should bind to. If $HOST and the config host are not defined, Hops will bind the server to the unspecified IPv6 or IPv4 address (:: or 0.0.0.0).

"hops": {
  "host": "10.10.10.10"
}

port

The port on which the server will be listening. By default Hops will try to read the environment variable $PORT. If neither $PORT nor the port config are set, Hops will try to find a free port, starting at >=8080.

"hops": {
  "port": "8080"
}

distDir

This is the file-system path to where the generated assets will be written and served from.

"hops": {
  "distDir": "<rootDir>/dist"
}

gracePeriod

The amount of time (in milliseconds) to wait after receiving a SIGTERM signal or catching an unhandled middleware exception and before killing the server completely.

{
  "gracePeriod": 60000
}

helmetConfig

The config to set security http headers via helmet.

Render Options

This preset has no runtime configuration options.

Mixin Hooks API

Caution: Please be aware that the mixin hooks are not part of the SemVer API contract. This means that hook methods and signatures can change even in minor releases. Therefore it's up to you to make sure that all hooks that you are using in your own mixins still adhere to the new implementation after an upgrade of a Hops packages.

configureServer(app, middleware, mode): app (pipe) core

Use this mixin hook to register middleware or configure the Express.js Application.

It receives the following arguments:

app

This is an Express.js application instance that allows you to reconfigure the application.

middleware

This is an object whose keys are middleware phases and the values are arrays in which middleware can be pushed.

These are the phases available:

1. initial - use this phase to register middleware that should be executed first
2. files - in this phase are middleware like express-static to serve static files
3. parse - this phase can be used to register middleware that parses data from incoming requests (e.g. cookie-parser or body-parser)
4. routes - this phase registers the universal render middleware that handles all the routes in your app
5. final - this phase may be used to register error handling or other middleware that should be run last

Additionally each phase also has a pre / post phase. E.g.: preinitial or postfiles.

mode

Describes the mode that the server is operating in, it can be one of: develop or serve.

const { Mixin } = require('hops-mixin');

module.exports = class MyMixin extends Mixin {
  configureServer(app, middleware, mode) {
    middleware.routes.push((req, res, next) => next());
    if (mode === 'serve') {
      middleware.preinitial.unshift((req, res, next) => next());
      middleware.postfinal.push((req, res, next) => next());
    }
    return app;
  }
};

inspectServer(app, target): app (sequence) core

Implement this hook to get access to the listening instance of http.Server (or https.Server). The second argument target will be one of develop, serve.

Use this hook to read the listening address or to register your application with a loadbalancer.

createServer(mode): app (override) core

With this mixin hook it is possible to get a fully configured Express.js application instance that you can register with your own server.

It accepts develop or serve as mode.

runServer(mode): void (override) core

In case you want to programmatically start a server, you can use this mixin hook.

It accepts develop or serve as mode.

Debugging

Available tags for the debug-module are:

• hops:express