WebSocket 是 HTML5 开始提供的一种在单个 TCP 连贯上进行全双工通信的协定。以前的推送技术应用 Ajax 轮询，浏览器须要一直地向服务器发送 http 申请来获取最新的数据，节约很多的带宽等资源。应用 webSocket 通信，客户端和服务端只须要一次握手建设连贯，就能够相互发送音讯，进行数据传输，更实时地进行通信。
一次握手建设 WebSocket 连贯 浏览器先向服务器发送个 url 以 ws:// 结尾的 http 的 GET 申请，响应状态码 101 示意 Switching Protocols 切换协定，服务器依据申请头中 Upgrade:websocket把 客户端的申请切换到对应的协定，即 websocket 协定。
响应头音讯中蕴含 Upgrade:websocket，示意它切换到的协定，即 websocket 协定。
响应 101，握手胜利，http 协定切换成 websocket 协定了，连贯建设胜利，浏览器和服务器能够随时被动发送音讯给对方了，并且这个连贯始终继续到客户端或服务器一方被动敞开连贯。为了加深了解，用 websocket 实现简略的在线聊天，先画个时序图，直观感触下流程。
网上有 websocket 在线测试工具，能够间接应用还是挺不便的，http://www.blue-zero.com/WebSocket/
以下是实现的例子，可供参考SocketService.php
<?php
/**
* Created by cywu
* Date: 2019/10/18
* Time: 14:33
*/
class SocketService
{
private $address = '0.0.0.0';
private $port = 8080;
private $_sockets;
public function __construct($address = '', $port='')
{if(!empty($address)){$this->address = $address;}
if(!empty($port)) {$this->port = $port;}
}
public function service(){
// 获取 tcp 协定号码。$tcp = getprotobyname("tcp");
$sock = socket_create(AF_INET, SOCK_STREAM, $tcp);
socket_set_option($sock, SOL_SOCKET, SO_REUSEADDR, 1);
if($sock < 0)
{throw new Exception("failed to create socket:".socket_strerror($sock)."n");
}
socket_bind($sock, $this->address, $this->port);
socket_listen($sock, $this->port);
echo "listen on $this->address $this->port ... n";
$this->_sockets = $sock;
}
public function run(){$this->service();
$clients[] = $this->_sockets;
while (true){
$changes = $clients;
$write = NULL;
$except = NULL;
socket_select($changes, $write, $except, NULL);
foreach ($changes as $key => $_sock){if($this->_sockets == $_sock){ // 判断是不是新接入的 socket
if(($newClient = socket_accept($_sock)) === false){die('failed to accept socket:'.socket_strerror($_sock)."n");
}
$line = trim(socket_read($newClient, 1024));
$this->handshaking($newClient, $line);
// 获取 client ip
socket_getpeername ($newClient, $ip);
$clients[$ip] = $newClient;
echo "Client ip:{$ip} n";
echo "Client msg:{$line} n";
} else {socket_recv($_sock, $buffer, 2048, 0);
$msg = $this->message($buffer);
// 在这里写你的业务代码
echo "{$key} clinet msg:",$msg,"n";
fwrite(STDOUT, 'Please input a argument:');
$response = trim(fgets(STDIN));
$this->send($_sock, $response);
echo "{$key} response to Client:".$response,"n";
}
}
}
}
/**
* 解决握手
* @param $newClient socket
* @return int 接管到的信息
*/
public function handshaking($newClient, $line){$headers = array();
$lines = preg_split("/rn/", $line);
foreach($lines as $line)
{$line = chop($line);
if(preg_match('/A(S+): (.*)z/', $line, $matches))
{$headers[$matches[1]] = $matches[2];
}
}
$secKey = $headers['Sec-WebSocket-Key'];
$secAccept = base64_encode(pack('H*', sha1($secKey . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11')));
$upgrade = "HTTP/1.1 101 Web Socket Protocol Handshakern" .
"Upgrade: websocketrn" .
"Connection: Upgradern" .
"WebSocket-Origin: $this->addressrn" .
"WebSocket-Location: ws://$this->address:$this->port/websocket/websocketrn".
"Sec-WebSocket-Accept:$secAcceptrnrn";
return socket_write($newClient, $upgrade, strlen($upgrade));
}
/**
* 解析接收数据
* @param $buffer
* @return null|string
*/
public function message($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;
}
/**
* 发送数据
* @param $newClinet 新接入的 socket
* @param $msg 要发送的数据
* @return int|string
*/
public function send($newClinet, $msg){$msg = $this->frame($msg);
socket_write($newClinet, $msg, strlen($msg));
}
public 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 $ns;
}
/**
* 敞开 socket
*/
public function close(){return socket_close($this->_sockets);
}
}
$sock = new SocketService();
$sock->run();前端页面：web.html
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1, maximum-scale=1, user-scalable=no">
<title>websocket</title>
</head>
<body>
<input id="text" value="">
<input type="submit" value="send" onclick="start()">
<input type="submit" value="close" onclick="close()">
<div id="msg"></div>
<script>
/**
0：未连贯
1：连贯胜利，可通信
2：正在敞开
3：连贯已敞开或无奈关上
*/
// 创立一个 webSocket 实例
var webSocket = new WebSocket("ws://192.168.31.152:8083");
webSocket.onerror = function (event){onError(event);
};
// 关上 websocket
webSocket.onopen = function (event){onOpen(event);
};
// 监听音讯
webSocket.onmessage = function (event){onMessage(event);
};
webSocket.onclose = function (event){onClose(event);
}
// 敞开监听 websocket
function onError(event){document.getElementById("msg").innerHTML = "<p>close</p>";
console.log("error"+event.data);
};
function onOpen(event){console.log("open:"+sockState());
document.getElementById("msg").innerHTML = "<p>Connect to Service</p>";
};
function onMessage(event){console.log("onMessage");
document.getElementById("msg").innerHTML += "<p>response:"+event.data+"</p>"
};
function onClose(event){document.getElementById("msg").innerHTML = "<p>close</p>";
console.log("close:"+sockState());
webSocket.close();}
function sockState(){var status = ['未连贯','连贯胜利，可通信','正在敞开','连贯已敞开或无奈关上'];
return status[webSocket.readyState];
}
function start(event){console.log(webSocket);
var msg = document.getElementById('text').value;
document.getElementById('text').value = '';
console.log("send:"+sockState());
console.log("msg="+msg);
webSocket.send("msg="+msg);
document.getElementById("msg").innerHTML += "<p>request"+msg+"</p>"
};
function close(event){webSocket.close();
}
</script>
</body>
</html>