PHP实时消息推送关于websocket技术
什么是WebSocket
WebSocket用于在Web浏览器和服务器之间进行任意的双向数据传输的一种技术。Web socket 协议基于 tcp 协议实现，包含初始的握手过程，以及后续的多次数据帧双向传输过程。
其目的是在WebSocket应用和WebSocket服务器进行频繁双向通信时，可以使服务器避免打开多个HTTP连接进行工作来节约资源，提高了工作效率和资源利用率。
WebSocket 的一些特点：
- 建立在 TCP 协议之上，服务器端的实现比较容易。
- 与 HTTP 协议有着良好的兼容性。默认端口也是80和443，并且握手阶段采用 HTTP 协议，因此握手时不容易屏蔽，能通过各种 HTTP 代理服务器。
- 数据格式比较轻量，性能开销小，通信高效。
- 可以发送文本，也可以发送二进制数据。
- 没有同源限制，客户端可以与任意服务器通信。
- 协议标识符是ws（如果加密，则为wss），服务器网址就是 URL。
实现原理
浏览器发出webSocket的连线请求，服务器发出响应，这个过程称为握手,握手的过程只需要一次，就可以实现持久连接。
php实现websocket实时消息推送
这里封装了一个类，具体看SocketService.php文件
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协议号码。
$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";
}
}
}
}
/**
* 握手处理
* @param $newClient socket
* @return int 接收到的信息
*/
public function handshaking($newClient, $line){
$headers = array();
$lines = preg_split("/\r\n/", $line);
foreach($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 Handshake\r\n" .
"Upgrade: websocket\r\n" .
"Connection: Upgrade\r\n" .
"WebSocket-Origin: $this->address\r\n" .
"WebSocket-Location: ws://$this->address:$this->port/websocket/websocket\r\n".
"Sec-WebSocket-Accept:$secAccept\r\n\r\n";
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 $ns;
}
/**
* 关闭socket
*/
public function close (){
return socket_close($this->_sockets);
}
}
$sock = new SocketService();
$sock->run();
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