Creating a server with Express

This example offers a pre-setup project for Express that allows you to get up and running in no time!

You can run the following command now init express to fetch the example to your local machine.

This Express example features the now.json configuration file below.

{
    "version": 2,
    "name": "express",
    "builds": [
        { "src": "**/*.js", "use": "@now/node" }
    ]
}

now.json

• The version property specifies Now 2.0.
• The name property sets the name for the deployment.
• The builds property allows Now to use a builder with a specific source target.

In this case we are going to use the @now/node builder to create a lambda function for every .js file in the project. There are two .js files - index.js and about/index.js, which will be made available at your Now servers' urls / and /about.

Deploy the app with Now.

$ now

Using Express with the @now/node builder

Note that we won't be creating a server, or using a listen() function to start a server, since Now is functioning as the server. Express is used just for routing and middleware purposes.

Calling express() returns a function that takes a standard Node.js http request object and http response object as parameters. Typically this function is defined as the variable app in an Node.js module, and that function also supports routing and middleware customization. And ... that function signature - (req, res) - is the exact shape that Now expects to be exported from a module. So you can return the result of the express() call, adding routing and middleware as you normally would with an express server.

Here's a very small example of using express:

const express = require('express')

const app = express()

app.get('*', (req, res) => {
    res.send(200, '<h1>Hello, world!</h1>')
})

module.exports = app

The req and res objects passed to the callback of app.get() will then be Express Request and Express Response objects, instead of Node's standard http request and response objects. So, you can use the Express res.send() method instead of the lower-level methods on the standard Node.js response object.

In the actual example code - index.js - you'll also note usage of the helmet package in the same way you'd use it in a typical express server:

app.use(helmet())

The helmet package adds extra security-related HTTP headers to HTTP responses sent from the express app.

Resources

• To find more information on using the Node.js Builder, please refer to the Node.js Builder (@now/node) documentation.

• Check out how to Deploy any of your applications with ZEIT Now.