Detailed explanation of socket push technology in PHP

Before the emergence of sockets, there were already solutions such as ajax scheduled requests and long polling, but none of them could meet the needs, so sockets were born. This article will share with you an example of php implementing socket push technology. It has a good reference value and I hope it will be helpful to everyone. Let’s follow the editor to take a look, I hope it can help everyone.

socket basic function socket

Summary of commonly used socket functions

Server side: socket_create creates a socket and sets basic parameters

socket_bind binds ip and port number

socket_listen listens

socket_accept client connection

socket_read reads client data

socket_write sends data to a single client

socket_close Close the connection

Client: socket_create Create socket and set basic parameters

socket_connect Connect socket

socket_write Send data to the server

socket_read Read server data

socket_close closes the connection

H5websocketNo more talk, go to the link

OK, start posting the code~

--------- -------------------------------------------------segmentation Line

Server code:

<?php
class WS {
 var $master;
 var $sockets = array();
 var $debug = false;//true为调试模式，输出log日志
 var $handshake = array();
 function __construct($address, $port){
 $this->master=socket_create(AF_INET, SOCK_STREAM, SOL_TCP) or die("socket_create() failed");
 socket_set_option($this->master, SOL_SOCKET, SO_REUSEADDR, 1) or die("socket_option() failed");
 socket_bind($this->master, $address, $port)  or die("socket_bind() failed");
 socket_listen($this->master,20)  or die("socket_listen() failed");
 
 $this->sockets[] = $this->master;
 $this->say("Server Started : ".date('Y-m-d H:i:s'));
 $this->say("Listening on : ".$address." port ".$port);
 $this->say("Master socket : ".$this->master."\n");
 
 while(true){
 $socketArr = $this->sockets;
 $write = NULL;
 $except = NULL;
 socket_select($socketArr, $write, $except, NULL); //自动选择来消息的socket 如果是握手 自动选择主机
 foreach ($socketArr as $socket){
 if ($socket == $this->master){ //主机
  $client = socket_accept($this->master);
  if ($client < 0){
  $this->log("socket_accept() failed");
  continue;
  } else{
  $this->connect($client);
  }
 } else {
  $bytes = @socket_recv($socket,$buffer,2048,0);
  if ($bytes == 0){
  $this->disConnect($socket);
  }
  else{
  $key = array_search($socket, $this->sockets);
  if (empty($this->handshake) || !isset($this->handshake[$key]) || !$this->handshake[$key]){
  $this->doHandShake($socket, $buffer, $key);
  }
  else{
  $buffer = $this->decode($buffer);
  echo $buffer.PHP_EOL;
  $key = array_search($socket, $this->sockets);
  $arr = $this->sockets;
  array_shift($arr);
  foreach ($arr as $s){
  $this->send($s, $buffer);
  }
  }
  }
 }
 }
 }
 }
 
 function send($client, $msg){
 $msg = $this->frame($msg);
 socket_write($client, $msg, strlen($msg));
 }
 function connect($socket){
 array_push($this->sockets, $socket);
 $this->say("\n" . $socket . " CONNECTED!");
 $this->say(date("Y-n-d H:i:s"));
 }
 function disConnect($socket){
 $index = array_search($socket, $this->sockets);
 socket_close($socket);
 $this->say($socket . " DISCONNECTED!");
 if ($index >= 0){
 echo 'unset index is:'.PHP_EOL;
 unset($this->sockets[$index]);
 }
 }
 function doHandShake($socket, $buffer, $handKey){
 $this->log("\nRequesting handshake...");
 $this->log($buffer);
 list($resource, $host, $origin, $key) = $this->getHeaders($buffer);
 $this->log("Handshaking...");
 $upgrade = "HTTP/1.1 101 Switching Protocol\r\n" .
  "Upgrade: websocket\r\n" .
  "Connection: Upgrade\r\n" .
  "Sec-WebSocket-Accept: " . $this->calcKey($key) . "\r\n\r\n"; //必须以两个回车结尾
 $this->log($upgrade);
 $sent = socket_write($socket, $upgrade, strlen($upgrade));
 $this->handshake[$handKey]=true;
 $this->log("Done handshaking...");
 return true;
 }
 function getHeaders($req){
 $r = $h = $o = $key = null;
 if (preg_match("/GET (.*) HTTP/" ,$req,$match)) { $r = $match[1]; }
 if (preg_match("/Host: (.*)\r\n/" ,$req,$match)) { $h = $match[1]; }
 if (preg_match("/Origin: (.*)\r\n/" ,$req,$match)) { $o = $match[1]; }
 if (preg_match("/Sec-WebSocket-Key: (.*)\r\n/",$req,$match)) { $key = $match[1]; }
 return array($r, $h, $o, $key);
 }
 function calcKey($key){
 //基于websocket version 13
 $accept = base64_encode(sha1($key . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11', true));
 return $accept;
 }
 function decode($buffer) {
 $len = $masks = $data = $decoded = null;
 $len = ord($buffer[1]) & 127;
 if ($len === 126) {
 $masks = substr($buffer, 4, 4);
 $data = substr($buffer, 8);
 } 
 else if ($len === 127) {
 $masks = substr($buffer, 10, 4);
 $data = substr($buffer, 14);
 } 
 else {
 $masks = substr($buffer, 2, 4);
 $data = substr($buffer, 6);
 }
 for ($index = 0; $index < strlen($data); $index++) {
 $decoded .= $data[$index] ^ $masks[$index % 4];
 }
 return $decoded;
 }
 function frame($s){
 $a = str_split($s, 125);
 if (count($a) == 1){
 return "\x81" . chr(strlen($a[0])) . $a[0];
 }
 $ns = "";
 foreach ($a as $o){
 $ns .= "\x81" . chr(strlen($o)) . $o;
 }
 return $ns;
 }
 
 function say($msg = ""){
 echo $msg . "\n";
 }
 function log($msg = ""){
 if ($this->debug){
 echo $msg . "\n";
 } 
 }
}
 
new WS('localhost', 4000);

Client code (H5):

<html>
 <head>
 <title>demo</title>
 <script src="https://cdn.bootcss.com/jquery/1.9.1/jquery.min.js"></script>
 </head>
 <body>
 <input type="text" id="content">
 <input type="button" value="send" id="send">
 <script type="text/javascript">
  var ws = new WebSocket("ws://localhost:4000");
  ws.onopen = function(){
  console.log("握手成功");
  }
  ws.onmessage = function(e){
  console.log("message:" + e.data);
  }
  ws.onerror = function(){
  console.log("error");
  }
  $("#send").click(function(){
  content = $("#content").val();
  console.log(content);
  ws.send(content);
  })
 </script>
 </body>
</html>

Then execute php demo.php to open the socket (steal a trick from the operation and maintenance, Execute nohup php demo.php & can be executed in the background under Linux), the browser will open multiple index.html, and communication can be established.

Code analysis:

1. The attribute $sockets array saves each accept connection (I don’t know if this description is correct);

2. The attribute $handshake array saves whether the connection is In the connection state;

Related recommendations:

PHP socket server framework workererman

Detailed introduction to websocket in php

Detailed explanation of socket module in python

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