What is the routing of .nodejs

Node.js is an open source, cross-platform JavaScript runtime environment that allows developers to write applications using JavaScript on the server side. In Node.js, routing is a very important concept that helps in mapping requests to the corresponding handlers to provide the correct response to the web application.

Route is a URL parser. It matches the URL requested by the client against the application's routing table to determine which handler will handle the request. When a client request reaches the web server, the server parses the requested URL and finds the corresponding route in the routing table based on the URL. Once a matching route is found, the server forwards the request to the appropriate handler for processing.

To better understand what routing is in Node.js, we can compare it to traditional web development techniques. In traditional web development, client requests are processed directly by the web server and responses are returned. This means that the web server must handle all requests, including those that do not need to be handled. This can cause excessive load on the server, and in high concurrency situations, the server may crash.

Compared with traditional web development technology, Node.js uses routing in a more flexible way, which can effectively relieve the pressure on the web server. In Node.js, routing can be classified according to the type of request and URL, and distribute the request to the corresponding handler. This allows us to call specific handlers when we only need to handle a specific request, effectively reducing the load on the server.

In Node.js, we can use a web framework called "Express" to implement routing. The Express framework allows us to specify how to handle requests by defining routes. In Express, a route consists of an HTTP method (such as GET, POST, PUT, etc.) and a path associated with the request. When Express receives a request, it looks for a matching route based on the entry in the routing table and forwards the request to the appropriate handler.

For example, the following is an example of using the Express framework to implement routing:

const express = require('express');
const app = express();

// 为GET请求添加路由
app.get('/', function (req, res) {
  res.send('Hello World!');
});

// 为POST请求添加路由
app.post('/', function (req, res) {
  res.send('Got a POST request');
});

// 为PUT请求添加路由
app.put('/user', function (req, res) {
  res.send('Got a PUT request at /user');
});

// 为DELETE请求添加路由
app.delete('/user', function (req, res) {
  res.send('Got a DELETE request at /user');
});

// 启动服务器
app.listen(3000, function () {
  console.log('Example app listening on port 3000!');
});

In the above example, we use the Express framework to define four routes, which are used to handle GET, POST, PUT and DELETE requests. When the client sends a request of the corresponding type, Express will automatically route the request to the corresponding handler.

In short, routing plays a very important role in Node.js. It allows us to distribute requests to specific handlers based on request type and URL, improving the performance and scalability of web applications. By using the Express framework, we can easily implement routing, providing richer functionality to our applications.

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