How to request other servers in nodejs

In recent years, front-end development technology has developed rapidly, and the scope of responsibilities of front-end developers has become more and more extensive. In addition to the common HTML, CSS, and JavaScript, front-end developers also need to master some back-end development skills, such as Node.js.

Node.js is an open source, cross-platform operating environment based on the JavaScript language, which can run JavaScript on the server side. It uses an event-driven, non-blocking I/O model and supports real-time data transmission. Therefore, under the modern development model of separation of front-end and back-end, Node.js has become an essential skill for front-end developers.

In Node.js, sending HTTP requests to other servers is not only a common operation, but also one of the officially provided core modules, the "http" module. This module provides functions for implementing HTTP client requests and HTTP server-side (i.e., Node.js's HTTP server).

In this article, we will explain how to use Node.js’s “http” module to send HTTP requests to other servers.

1. Use the http.request() method to send a request

http.request(options[, callback])

This method returns an http.ClientRequest object. options is an object containing the following properties:

• protocol - the protocol used by the request, such as http: or https:.
• hostname - The domain name or IP address of the server to be requested.
• port - The port number that the server responds to.
• path - The requested path.
• method - HTTP method used by the request, such as GET, POST.
• headers - Object containing request headers.

callback is a function called when a response is received from the server.

In the following example, we send a GET request to jsonplaceholder.typicode.com and return the details of a blog post:

const http = require('http')

const options = {
  hostname: 'jsonplaceholder.typicode.com',
  path: '/posts/1',
  method: 'GET'
}

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

  res.on('data', (data) => {
    console.log(`响应主体: ${data}`)
  })

  res.on('end', () => {
    console.log('响应中已无数据。')
  })
})

req.on('error', (error) => {
  console.error(`请求遇到问题: ${error}`)
})

req.end()

In this example, an http.ClientRequest is created Object, a GET request is sent to the server and the data in JSON format is specified. When a response is received from the server, print out the response status code and response body.

2. Use the http.get() method to send a request

http.get(options[, callback])

This method is the same as http.request( ) method is similar, but it can only implement GET requests.

In the following example, we use the http.get() method to send a GET request to the same server:

const http = require('http')

http.get('http://jsonplaceholder.typicode.com/posts/1', (res) => {
  console.log(`状态码: ${res.statusCode}`)

  res.on('data', (data) => {
    console.log(`响应主体: ${data}`)
  })

  res.on('end', () => {
    console.log('响应中已无数据。')
  })
}).on('error', (error) => {
  console.error(`请求遇到问题: ${error}`)
})

In this example, we use the http.get() method to send a GET request to the jsonplaceholder The .typicode.com server sends a GET request and when the response is received from the server, it prints out the response status code and response body.

3. Use the request library to send requests

In addition to the "http" module provided by Node.js, there are also some request libraries, such as request and axios. These libraries have more advanced features, support Promises, handle redirects and errors, etc.

In the following example, we use the request library to send a GET request to the jsonplaceholder.typicode.com server:

const request = require('request')

request('http://jsonplaceholder.typicode.com/posts/1', (error, response, body) => {
  console.log(`状态码: ${response.statusCode}`)
  console.log(`响应主体: ${body}`)
})

In this example, we use the request library to send a GET request to the jsonplaceholder.typicode.com server A GET request is sent and the response status code and response body are printed out when the response is received from the server.

Summary

This article describes how to use the "http" module of Node.js to send HTTP requests to other servers. Basic request operations can be implemented using the http.request() method and http.get() method, and request libraries (such as request and axios) can support more advanced features. Developers can choose different ways to implement HTTP request operations according to their own needs and habits.

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