How to send AJAX requests in Node.js

With the development of AJAX technology, more and more front-end applications need to send asynchronous requests to the server in order to update status, obtain new data or perform some operations. Node.js is a full stack framework that allows us to use JavaScript on the server side to be able to perform these operations in response to AJAX requests sent by the client. In this article, we will explore how to send AJAX requests in Node.js.

1. Installation dependencies

Node.js has a built-in http module for HTTP requests and responses. In order to use AJAX technology, we need to use the http.request() method in Node.js.

Before we start, we need to install the http module.

Can be installed through the following command:

npm install http --save

After using the above command in the command line to install, we can see that http related files have been downloaded to the project.

2. Use http.request() to send AJAX requests

In Node.js, we can use the http.request() method to send AJAX requests. The method needs to pass an options object, which sets some parameters of the request, such as request URL, request method, and request headers. Here, we use the POST method as an example.

const http = require('http');

const options = {
  hostname: 'localhost',
  port: 3000,
  path: '/api/add',
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  }
};

const req = http.request(options, res => {
  console.log(`statusCode: ${res.statusCode}`);

  res.on('data', d => {
    process.stdout.write(d)
  });
});

req.on('error', error => {
  console.error(error)
});

req.write('{"name": "John Doe"}');
req.end();

The above code sends a POST request to the server with the URL localhost:3000/api/add. The request header contains Content-Type and its value. is application/json, and the request body is JSON data {"name": "John Doe"}.

3. Use a third-party library to send AJAX requests

Although Node.js has a built-in http module, it is very troublesome to send AJAX requests in some complex scenarios. Therefore, for convenience, we can use some excellent third-party libraries, such as axios, request, etc.

Among them, axios is probably the most popular library. It can be used in both the browser and Node.js. It provides a very simple API that allows us to easily Send an AJAX request.

We can install axios by the following command:

npm install axios --save

Use axios in the code:

const axios = require('axios');

axios.post('http://localhost:3000/api/add', {
    name: 'John Doe'
})
.then(response => {
    console.log(response.data);
})
.catch(error => {
    console.log(error);
});

The above code goes to the URL A POST request was sent to the server at http://localhost:3000/api/add, and the request body was JSON data{"name": "John Doe"} . On success, print the data response.data returned by the server.

4. Summary

This article introduces the method of using AJAX technology to initiate asynchronous requests to the server in Node.js, including using the http module and third-party libraryaxios Sending AJAX requests will be very useful for front-end developers who are good at Node.js. We recommend using third-party libraries as they not only provide better APIs but also handle some of the complex details and edge cases for us.

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