Building a Web server using Node is very easy

• Node provides a single core module: HTTP
• The HTTP module is responsible for helping you create authoring servers

1. Load HTTP core module, HTTP is a variable name, can be customized

var http = require('http')
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2. usehttp.createServer()Method to create a Web server
   
   Return a Server instance

var server = http.createServer()
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3. What does the server do?

• Providing services: Services to data
• Send the request
• Receiving a request
• Handle the request
• Give feedback (send a response)
• Register the Request request event

When the client request comes in, the server’s request event is automatically triggered and the second argument is executed: the callback handler

server.on('request'.function () {
  console.log('Received client request')})Copy the code

4. Bind the port number and start the server

server.listen(3000.function () {
  console.log('The server started successfully and can be accessed at http://127.0.0.1:3000/')})Copy the code

• Perform:
  
  
• Access:http://127.0.0.1:3000/
  
  
  
  Each access adds a record

HTTP requests and responses

var http = require('http')

var server = http.createServer()
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server.on('request'.function (request, response) {
  // http://127.0.0.1:3000/ result :/
  // http://127.0.0.1:3000/a result :/ a
  Results: / / http://127.0.0.1:3000/foo/b/foo/b
console.log('Received the request from the client. The request path is:' + request.url)


  The response object has a method: write can be used to send response data to the client
  // Write can be used multiple times, but the response must be terminated with end, otherwise the client will wait
   response.write('hello')
   response.write(' nodejs')

  // Tell the client that my words are finished and you can present them to the user
   response.end()

  // Since our server is currently very weak, no matter what request, can only respond to hello nodejs
  / / thinking:
  // I want different results when requesting different paths
  / / such as:
  // / index
  / / / login
  / / / register registration
  // /haha
})

server.listen(3000.function () {
  console.log('The server started successfully and can be accessed at http://127.0.0.1:3000/')})Copy the code

Send different response results based on different request paths

var http = require('http')

1. Create a Server
var server = http.createServer()

// 2. Listen to the request event and set the request handler
server.on('request'.function (req, res) {
  console.log('Request received, request path:' + req.url)
  console.log('Request my client's address is:', req.socket.remoteAddress, req.socket.remotePort)

  // res.write('hello')
  // res.write(' world')
  // res.end()

  // The above method is cumbersome, recommend to use a simpler way, directly end and send the response data
  // res.end('hello nodejs')

  // Send different response results according to different request paths
  // 1. Obtain the request path
  // req.url retrieves the portion of the path after the port number
  // All urls start with a /
  // 2. Determine the path processing response

  var url = req.url

  if (url === '/') {
    res.end('index page')}else if (url === '/login') {
    res.end('login page')}else if (url === '/products') {
    var products = [{
        name: 'apple'.price: 8888
      },
      {
        name: Pineapple 'X'.price: 5000
      },
      {
        name: 'Pepper X'.price: 1999}]// The response content can only be binary data or a string
    / / digital
    / / object
    / / array
    / / a Boolean value
    res.end(JSON.stringify(products))
    // Convert an array to a string
  } else {
    res.end('404 Not Found.')}})// 3. Bind the port number to start the service
server.listen(3000.function () {
  console.log('Server started successfully, accessible... ')})Copy the code