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How to install Express

Overview​

What is Express?​

Express is a Node.js framework inspired by Sinatra for Ruby: it's based on minimalism with a penchant for performance. Express is part of the MEAN fullstack: MongoDB, Express, Angular.js, and Node.js. MongoDB may be setup in a separate guide.

Express is supported using Passenger to manage isolated processes.

Quickstart​

All steps are done from the Terminal:

  1. Create a Passenger-compatible filesystem layout.

    • In this example, our app will reside in /var/www/express. The filesystem layout looks like: 
      express
      ├── app.js
      ├── public
      │   └── .htaccess
      └── tmp

  2. From the root directory, /var/www/express, install Express locally with NPM:

    npm install express

  3. Now create a startup file named app.js within express/. Copy and paste the following as a sample application in the root folder:

    var express = require('express')
    var app = express()

    app.get('/', function (req, res) {
     res.send('Hello World!');
    })

    var server = app.listen(3000, function () {
     var host = server.address().address
     var port = server.address().port

     console.log('Example app listening at http://%s:%s', host, port)
    })

  4. Inform Passenger that the app should be launched as Node.js application

    echo "PassengerNodejs /usr/bin/node" > public/.htaccess

  5. Lastly, connect public/ to a Subdomain within Control Panel. (Addoin Domains > List)

  6. Enjoy!

Using Express Generator​

Express Generator is a separate application to facilitate filesystem creation for an app. It may be installed separately from npm:

npm install -g express-generator

Now run express <appname> where appname is a new app to create, e.g. cd /var/www && express express to create a new app located in /var/www/express. The application, express, will scaffold a new filesystem layout that is compatible with Passenger.

Change directories to the newly-created app root, and run npm install to install dependencies.

**Note: **astute readers will note that npm is invoked first without -g, then with -g. -g is a flag that installs the package globally in /usr/local. In certain situations, where an application is loosely-coupled and serves no integral function, placing it under /usr/local would be better so that binaries are picked up under /usr/local/bin.

Important: once generated the startup file is located as bin/www. app.js is a separate application launched after initialization. To make this work with Passenger, add PassengerStartupFile www/bin to .htaccess in public/.

See also​