A powerful AI tool that can help with coding tasks is ChatGPT, a language model developed by OpenAI. In this article, we will show you how to harness the power of ChatGPT to generate a complete Node.js API, from start to finish - without the need to write a single line of code by yourself. Let’s get started …
So here is the input for ChatGPT, just a describe of what the API should do:
“Generate code for a Node.js / Express application which has an endpoint url2qr. The endpoint must accept HTTP POST requests. Body data of this request is in JSON format containing a property named url. The url received is then converted to a QR code image. The image is returned as a PNG file.”
After hitting return, ChatGPT is starting to generate an answer simitlar to what you can see in the following screenshot:
The Node.js/Express code is fully generated:
const express = require('express');
const bodyParser = require('body-parser');
const qr = require('qr-image');
const app = express();
app.use(bodyParser.json());
app.post('/url2qr', (req, res) => {
const url = req.body.url;
const qr_svg = qr.image(url, { type: 'png' });
res.type('png');
qr_svg.pipe(res);
});
app.listen(3000, () => {
console.log('Server running on port 3000');
});
This code creates ourNode.js/Express application with an endpoint /url2qr that accepts HTTP POST requests.
The first line const express = require('express'); imports the Express module. Express is a web application framework for Node.js that allows for easy routing and handling of HTTP requests.
The second line const bodyParser = require('body-parser'); imports the body-parser middleware. This middleware is used to parse the request body of an HTTP request and make it available as a JavaScript object in the request object.
The third line const qr = require('qr-image'); imports the qr-image library. This library is used to generate QR code images from a given input (in this case, a URL).
The fourth line const app = express(); creates an instance of the Express application.
The line app.use(bodyParser.json()); sets up the body-parser middleware to parse JSON request bodies.
The line app.post('/url2qr', (req, res) => { sets up an endpoint for the Express application that listens for HTTP POST requests to the /url2qr path. The callback function passed as the second argument to the .post() method is executed when a POST request is made to that path. The function takes two arguments, req and res, which represent the request and response objects respectively.
The line const url = req.body.url; extracts the url property from the request body.
The line const qr_svg = qr.image(url, { type: 'png' }); generates a QR code image from the URL and assigns it to the variable qr_svg
The line res.type('png'); sets the content type of the response to image/png.
The line qr_svg.pipe(res); pipes the QR code image to the response object, which sends it to the client as a PNG file.
The line app.listen(3000, () => { starts the Express application and listens for incoming requests on port 3000.
The line console.log('Server running on port 3000'); logs a message to the console that the server is running on port 3000.
After starting the server, the code will listen on port 3000 for any incoming request on the endpoint /url2qr and when a post request is made to this endpoint it will convert the url given in the body of the request to QR code and sends it back to the client as a PNG file.
With the code available you now need to perform the following steps:
- Create a new directory for your project and navigate to it in the command line.
- Initialize a new Node.js project by running npm init. This will create a package.json file in your project directory.
- Install the express, body-parser, and qr-image dependencies by running the following command:
npm install express body-parser qr-image
Finally create a new file in your project directory called server.js or any name you prefer and add the code I provided in the previous answer.
Testing The Generated Code
You can start the server by running the code in your Node.js environment, for example by using the node command in the command line:
$ node server.js
Once the server is running, you can use a tool like curl or httpie to make a POST request to the endpoint and pass in the desired URL in the request body. Here’s an example using curl:
$ curl -X POST -H "Content-Type: application/json" -d '{"url":"https://example.com"}' http://localhost:3000/url2qr > qr.png
You can also use a tool like postman to make the request.
You should now have a qr.png file containing the QR code image of the URL you passed in the request:
