How to send an HTTP GET request using Node.js

Node.js is a JavaScript runtime based on the Chrome V8 engine, which allows us to run JavaScript on the server side. Generally speaking, as Node.js grows in popularity, it is increasingly used to build server-side applications, and HTTP request handling is the foundation of server-side applications. In this article, we will discuss how to send HTTP GET requests using Node.js.

HTTP GET request is a request method used to obtain data from the server. It is a stateless request. The server disconnects immediately after responding to the request.

Node.js provides a built-in http module that allows us to easily send HTTP requests. The http module can be imported through the require() function. The following is an example code that uses Node.js to send an HTTP GET request:

const http = require('http');

http.get('http://www.example. com/', (res) => {
console.log(Status code: ${res.statusCode});
console.log('Response header:\n', res.headers);
res.on('data', (chunk) => {

console.log(`响应主体: ${chunk}`);

});
res.on('end', () => {

console.log('响应结束');

});
}).on('error', (e) => {
console.error(Error: ${e.message} );
});

In the above sample code, we used the http.get() function to send an HTTP GET request. This function requires two parameters: the first parameter is the URL of the request, and the second parameter is the callback function. The callback function is used to handle the response and can also handle errors when an error occurs.

In the callback function, we first output the status code and response header of the HTTP response. Then use the res.on('data') function to subscribe to the data stream of the http response and output the response body. Finally, we use the res.on('end') function to notify us that the response has ended.

When sending an HTTP GET request, the request header usually contains some special information, such as: User-Agent, Cache-Control, Accept, etc. In order to better control our requests, we can use the options parameters provided by Node.js, for example:

const http = require('http');

const options = {
hostname: 'www.example.com',
path: '/path/to/resource',
port: 80,
method: 'GET',
headers: {

'User-Agent': 'Mozilla/5.0',
'Accept-Language': 'en-US,en;q=0.5',
'Referer': 'http://www.example.com/index.htm',
'Connection': 'keep-alive',
'Cache-Control': 'max-age=0'

}
};

http.get(options, (res) => {
console.log(Status code: ${res.statusCode});
console.log('Response header:\n', res.headers);
res.on('data', (chunk) => {

console.log(`响应主体: ${chunk}`);

}) ;
res.on('end', () => {

console.log('响应结束');

});
}).on('error', (e) => {
console.error(Error: ${e.message});
});

In the above code, we define an options object containing multiple parameters. Here we specify the HTTP request method ('GET') to be sent, the requested host name (www.example.com), the requested port (80), the requested path (/path/to/resource), and other related request header information.

In conclusion, in this article, we learned how to send HTTP GET request using Node.js. We also use the options object to have more control over HTTP requests to suit our specific needs. The http module provided by Node.js is a powerful tool that allows us to easily send HTTP requests and interact with other applications and services.

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