How to Build an Express App in Node That Reads From a Headless CMS

Introduction

I assume that you will read tutorials like I do: having your IDE ready to follow along. I also assume that you are familiar with basic JavaScript and have node & npm installed. My targeted audience is the "advanced beginner", so someone who has basic understanding of the environment and languages but needs a little guidance on how to start building great applications, or the advanced creator who collects ideas and dabbles into new worlds. You can also download the complete project and use this tutorial as explanation.

Complete files: Download ZIP View on GITHub

blua.blue

The headless neoan3 based CMS blua.blue is open source and can be hosted wherever you want. For this simple tutorial, we are going to sign up here: blua.blue registration

After confirming our email, we are ready to use the API to our liking. It might make sense to write your first article if you feel like it (as a matter of fact, this very toturial has been created in blua.blue).

We are using node as once we gather are solid understanding of the capabilities of a headless CMS, we will see the SEO advantage of rendering content server side (but that is a topic for another post).

1. Installing prerequisites

Let's create a project folder. You can name this folder however you want, but I will simply refer to it as "app-folder" here. Let us start by installing the we will need via npm

npm install express pug axios --save

While express will be our server we will use pug (former jade) as a template engine and axios to handle our requests to blua.blue

By default, express expects templates to be in the folder views, so we might as well create this folder now. To present you with an overview, this will be the file structure at the end:

views/

-- list.pug

blua-api.js

server.js

To give express a basic spin, let's test if everything runs: Create a file list.pug in /views and enter some basic markup.

html
    head
        title My articles   
    body
        h1 Test

Now we create the file (if you haven't already) server.js and start defining your express server:

const express = require('express');
const app = express();

// Routing is crucial. If you are not familiar with route definitions, please look into express documentation 

app.get('/', function (req, res) {
       res.render('list', function(err,html){
            res.send(html);
        })
});

// And let us serve on port 3000 
app.listen(3000, function () {
    console.log('Example app listening on port 3000!');
});

Running node serve.js should give us a running application @ http://localhost:3000

2. Api wrapper

One could argue that it is overkill for our purposes, but I want to create a setup that allows you to go beyond this tutorial with the codebase we create. Let us therefore create the file blua-api.js now:

const axios = require('axios');

// Change this line if you are hosting blua.blue yourself
let baseUrl = 'https://blua.blue/api.v1/';

const api = {
    config: {
        baseURL: baseUrl,
        timeout: 2000,
        headers:{}
    },
    token: false,
    connected:false,
    init: async (user, password) => {
        if(!this.connected){
            let instance = axios.create(api.config);
            await instance.post('login',{username:user,password:password}).then(res=>{
                api.token = res.data.token;
                api.connected = true;
                api.config.headers.Authorization = `Bearer ${res.data.token}`;
                instance = axios.create(api.config);
            }).catch(err=>{
                console.log(err);
                process.end()
            });
            return instance;
        }
    }
};

module.exports = api;

As you can see we are prepared to make authorized calls with a JWT token with one simple step. The function init returns an axios instance. If you are not familiar with axios, or would rather use javaScript's fetch, feel free to implement another solution. Here we want to make sure that the very first call authenticates us and all subsequent calls are authenticated. The usage will be:

const bluaBlue = require('./blua-api.js');

bluaBlue.init('your-username','your-password').then(api=>{
    // make any call documented in https://blua.blue/api-documentation
    api.get('article?slug=my-article').then(...);

});

Note: While not covered in this tutorial, your JWT will expire once in a while. You will receive "unauthorized" 401 responses in such cases that you can catch. You may simply run init again but set the wrappers property connected to false so authentication runs again.

3. Collecting & Rendering a list of your articles

I don't want to get into design in this tutorial, so we'll use bootstrap for a basic expandable list since I think most people have at least a minimum experience with it.

More or less taken exactly from bootstrap's documentation, let's get back and enhance our template (views/list.pug)

html
    head
        title My articles
        // let's use the bootstrap files via CDN
        link(rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css")
        script(src="https://code.jquery.com/jquery-3.3.1.slim.min.js")
        script(src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js")
        script(src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js")
    body
        .container
            h1 My articles
            .accordion#article-list
                // We don't have any articles yet, but we will want to iterate over them.
                each article in articles
                    .card
                        .card-header
                            h2.mb-0
                                button.btn.btn-link(type="button" data-toggle="collapse" data-target="#"+article.slug) #{article.name}
                        .collapse(id=article.slug data-parent="#article-list")
                            .card-body
                                p #{article.teaser}
                                a.btn.btn-success(href="https://blua.blue/article/"+article.slug target="_blank") read

So what do we want to achieve? Our app is supposed to fetch all articles of a particular author (you?) and list them. So we will redesign our server.js to make a call to blua.blue when a client requests the home page ( get('/') ). As mentioned before, the api wrapper sends authenticated calls after initiation. The easiest approach is to wrap our server logic in this wrapper.

const express = require('express');
const app = express();
app.set('view engine', 'pug');
const bluaBlue = require('./blua-api.js');


// you will want to set your credentials right
bluaBlue.init('your-username','your-password').then(blua=>{
    app.get('/', function (req, res) {
        // set the author accordingly. If you have not written any articles yet, use "neoan" to test
        blua.get('articleList?author=your-username').then(d=>{
            // be sure to include the data here
            res.render('list', {articles:d.data}, function(err,html){
                res.send(html);
            })
        });
    });

    app.listen(3000, function () {
        console.log('Example app listening on port 3000!');
    });
});

That's it!

If you run in any problems when running node server.js , you might want to run your application in debug mode. For Windows this means running set DEBUG=express:* node server.js .

Now you are on your own. Can you create dynamic routes for your articles rather than directing the visitors to blua.blue? Can you look into the objects and find additional content you want to use? Are you bold enough to try to update one of your articles?

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