Node.js Youtube-DL Express Example to Build Youtube Video Thumbnail Downloader in Browser Using JS

Welcome folks today in this blog post we will be using the youtube-dl library to build youtube video thumbnail downloader in browser using javascript. All the full source code of the application is shown below.

Get Started

In order to get started you need to initialize a new node.js project using the below command as shown below

npm init -y

npm i express

Now we need to make the index.js file and copy paste the following code

index.js

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

const fs = require("fs");
 
const dirpath = path.join(__dirname);
  
const {exec} = require('child_process');
 
const app = express();
 
app.use(bodyParser.urlencoded({ extended: false }))
 
app.use(bodyParser.json())
 
app.get('/', (req, res) => {
    res.sendFile(__dirname + "/index.html")
})

app.listen(5000, () => {
    console.log('listening on port 5000')
})

const express = require('express');

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

const path = require("path");

const fs = require("fs");

const dirpath = path.join(__dirname);

const {exec} = require('child_process');

const app = express();

app.use(bodyParser.urlencoded({ extended: false }))

app.use(bodyParser.json())

app.get('/', (req, res) => {

res.sendFile(__dirname + "/index.html")

})

app.listen(5000, () => {

console.log('listening on port 5000')

})

As you can see we are importing the express library and then we are applying the bodyparser middleware and then we are loading the index.html file when user goes to the / home route.

index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Youtube Video Thumbnail Downloader in Node.js</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
</head>
<body>
    <div class="container">
        <h1 class="text-center">
            Youtube Video Thumbnail Downloader in Node.js
        </h1>
        <form action="/download" method="post">
            <div class="form-group">
                <label for="url">Enter Youtube URL:</label>
                <input type="text" name="url" required placeholder="Enter Youtube URL" class="form-control">
            </div>
            <div class="form-group">
                <button class="btn btn-danger btn-block">
                    Download Thumbnail
                </button>
            </div>
        </form>
    </div>
</body>
</html>

<!DOCTYPE html>

<head>

<title>Youtube Video Thumbnail Downloader in Node.js</title>

</head>

<body>

Youtube Video Thumbnail Downloader in Node.js

</h1>

<label for="url">Enter Youtube URL:</label>

</div>

Download Thumbnail

</button>

</div>

</form>

</div>

</body>

</html>

As you can see we are importing the bootstrap library cdn and then we have the simple html5 form where we allow the user to enter the youtube video url and then we have the button to download the thumbnail. Here we are making the post request to the /download route. Now we need to define this route inside the index.js file as shown below

index.js

app.post('/download', (req, res) => {
    var url = req.body.url
 
    exec(`youtube-dl --write-all-thumbnails ${url} --skip-download`, (err, stdout, stderr) => {
        if (err) {
            console.log(err)
        }
        else {
            // download the thumbnail as a attachment
            fs.readdir(dirpath, function (err, files) {
              const imagefiles = files.filter(
                (el) => path.extname(el) === ".jpg" || ".webp"
              );
              // do something with your files, by the way they are just filenames...
                console.log(imagefiles)
            });
        }
    })
 
})

app.post('/download', (req, res) => {

var url = req.body.url

exec(`youtube-dl --write-all-thumbnails ${url} --skip-download`, (err, stdout, stderr) => {

if (err) {

console.log(err)

}

else {

// download the thumbnail as a attachment

fs.readdir(dirpath, function (err, files) {

const imagefiles = files.filter(

(el) => path.extname(el) === ".jpg" || ".webp"

);

// do something with your files, by the way they are just filenames...

console.log(imagefiles)

});

}

})

As you can see we are getting the url of the youtube video and then we are executing the command using the exec() method and inside that we are using the youtube-dl library to download all the thumbnails of the video.