nodejs usage request

Node.js is an open source, cross-platform JavaScript running environment based on the Chrome V8 JavaScript engine, which enables JavaScript to run independently of the browser. It provides many powerful modules to make web development easier. Among them, the request module is the most widely used HTTP module and can be used to send HTTP/HTTPS requests.

1. Install request

You can use the following command to install request in your project directory:

npm install request

2. Use request

in your The request module is quoted in the script:

var request = require('request');

The request() method is the most commonly used method of this module. The following is a simple request() request:

request('https://www.baidu.com', function (error, response, body) {
  console.log('error:', error); //打印错误信息
  console.log('statusCode:', response.statusCode); //打印响应状态码
  console.log('body:', body); //打印HTML正文
});

It should be noted here that request( ) method's first parameter is the request URL, and its second parameter is the callback function. The callback function has three parameters, which are the error message when the request fails, the response object and the string form of the response content.

Request headers

You can also use the request() method to pass some request headers.

var options = {
  url: 'https://api.github.com/repos/request/request',
  headers: {
    'User-Agent': 'request'
  }
};
 
function callback(error, response, body) {
  if (!error && response.statusCode == 200) {
    const info = JSON.parse(body);
    console.log(info.stargazers_count + " Stars");
    console.log(info.forks_count + " Forks");
  }
}
 
request(options, callback);

In this example, we pass a User-Agent header in the request header to indicate the source of the request.

POST request

Send parameters to the server. The POST method using HTTP is the most common request. The request() method also supports POST requests.

var request = require('request');
request.post('http://service.com/upload', {form:{key:'value'}}, function(error, response, body) {
  //上传文件或者其他操作
});

When using the request() method to send a POST request, the first parameter represents the URL of the request, and the second parameter is the parameter that needs to be sent during the POST request. Here, we can see that we sent a key-value pair to the server, with the variable name key and the variable value value.

GET request

The GET request is another example of a simple request.

var request = require('request');
request.get('http://www.baidu.com', function(error, response, body) {
  console.log(body);
});

In a GET request, we can simply pass the requested URL and then use the callback function to get the response body.

3. Summary

In this article, we introduced request, one of the Node.js modules. Sending HTTP/HTTPS requests in web development is a very important task. Using the request module, you can easily send requests to the server and get responses. Through this article, you can learn how to install and use the request module in Node.js scripts, and understand how to build and send basic GET, POST requests and request headers.

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