Initialize package.json

$ npm init -y

Express

Install express

$ npm install express --save

Basic Routes

const express = require('express');
const bodyParser = require('body-parser');

var app = express();

app.use(bodyParser.json()); // support json encoded bodies
app.use(bodyParser.urlencoded({ extended: true })); // support encoded bodies

app.get('/query', (req, res) => {
  let q = req.query.q;
  res.send(`Got query ${q}`);
});

// POST http://localhost:8080/api/users
// parameters sent with 
app.post('/api/users', (req, res) => {
    var id = req.body.id;
    var token = req.body.token;
    var geo = req.body.geo;

    res.send(user_id + ' ' + token + ' ' + geo);
});

app.listen(port, () => {
    console.log(`Started on port ${port}`);
});

Debugging

Handling Static Routes

Use the express.static() middleware to specify directory containing the static files:

// file access at http://127.0.0.1:3000/style.css
app.use(express.static(__dirname + '/public'));

// file access at http://127.0.0.1:3000/public/style.css
app.use('/public', express.static(process.cwd() + '/public'));

Using Handlebars Templating Engine

Install hbs

$ npm install hbs --save

Then configure express to use handlebars:

const hbs = require('hbs');
app.set('view engine', 'hbs');

Create a views/ sub-directory (views/ is the default directory Express uses for templates)

$ mkdir views

Use res.render() to inject variables into the hbs files:

    res.render('about.hbs', {
        pageTitle: 'About Page',
        currentYear: new Date().getFullYear()
    });

pageTitle and currentYear can then be used within about.hbs:

    <h1>{{ pageTitle }}</h1>
    <p>Some text here</p>
    <footer>
      <p>Copyright {{ currentYear }}</p>
    </footer>

To use partials, use registerPartials to specify the directory containing the partials:

hbs.registerPartials(__dirname + '/views/partials');

Then, too include a partial (eg. /views/partials/footer.hbs) within an hbs file:

{{> footer }}

Handlebars helpers can be used for common functions. For example:

hbs.registerHelper('getCurrentYear', () => {
    return new Date().getFullYear();
});

hbs.registerHelper('screamIt', (text) => {
    return text.toUpperCase();
});

and then in the templates you can use {{ getCurrentYear}} or {{ screamIt 'upper case me' }}, or {{ screamIt textVar }} to run the functions.

Express Middleware

Use app.use() to register middleware. The middleware will be executed according to the order you call to app.use():

const fs = require('fs');

app.use((req, res, next) => {
  var now = new Date().toString();
  var log = `${now}: ${req.method} ${req.url}`;
  
  fs.appendFile('server.log', log + '\n', (err) => {
    if (err) {
      console.log('Unable to append to server.log');
    }
  });
  
  console.log(log);
  next();
});

Deplying to Heroku

Logging in

$ heroku help
$ heroku login

Adding SSH keys

$ heroku keys:add

List SSH keys on account

$ heroku keys

Remove SSH keys on account

$ heroku keys:remove

Test SSH keys with Heroku

$ ssh -v git@heroku.com

Application Port

Set port to process.env.PORT in server.js to heroku can set the port for the application using process.env.PORT environment variable.

Package.json

Setup a start script in package.json for the Heroku to start the app:

{
    ...
    "scripts": {
        "start": "node server/server.js"
        ...
    }
}

This is necessary because Heroku doesn't know the name of the file to use to start the app.

Push up application to Heroku

Run heroku create from within the application:

$ heroku create

This will add a remote for Heroku:

$ git remote -vv
heroku	https://git.heroku.com/hidden-scrubland-50797.git (fetch)
heroku	https://git.heroku.com/hidden-scrubland-50797.git (push)

Now use git push to push the application up to Heroku

$ git push heroku master

To open the application in your web browser use:

$ heroku open

thayton/express-boilerplate