背景：
前段时间有个小需求：进入页面后需要根据数据库状态来自行跳转。去查了查，大部分都是用轮询做。自己觉得其实轮询也不是不可以，但是总觉比较尴尬。
因为本身的模式应该是以状态为主体，页面部分为客体，当状态发生变化的时候，主动把信号传给页面，然后页面跟着做跳转。如果用轮询，就变成了以页面为
主体，状态为客体，页面不断的给请求，如果状态变了，然后自己做跳转。然后看到了websocket，不过说实话不懂这东西。socket编程一直都有点模糊。于是
稍微看看这到底是神马。
主题：
去github上查了一波，找到了一个小实例很适合初学。
地址：https://github.com/ghedipunk/PHP-Websockets
主要步骤：
建立socket并监听
服务器端 ：
$this->master = socket_create(AF_INET, SOCK_STREAM, SOL_TCP) or die("Failed: socket_create()");socket_set_option($this->master, SOL_SOCKET, SO_REUSEADDR, 1) or die("Failed: socket_option()");
socket_bind($this->master, $addr, $port) or die("Failed: socket_bind()");
socket_listen($this->master,20) or die("Failed: socket_listen()");
客户端：
var host = "ws://127.0.0.1:9000"; // SET THIS TO YOUR SERVER socket = new WebSocket(host);
websocket协议的三次握手：
服务端
主要是对头部信息的拆分，拿到其中的sec-websocket-key，进行拼接后加密再编码返回给客户端。（PS对这块真不太熟，具体可参见下边的链接，很详细）
提取代码如下
protected function doHandshake($user, $buffer) {
$magicGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
$headers = array();
$lines = explode("\n",$buffer);
foreach ($lines as $line) {
if (strpos($line,":") !== false) {
$header = explode(":",$line,2);
$headers[strtolower(trim($header[0]))] = trim($header[1]);
}
elseif (stripos($line,"get ") !== false) {
preg_match("/GET (.*) HTTP/i", $buffer, $reqResource);
$headers[‘get‘] = trim($reqResource[1]);
}
}
if (isset($headers[‘get‘])) {
$user->requestedResource = $headers[‘get‘];
}
else {
// todo: fail the connection
$handshakeResponse = "HTTP/1.1 405 Method Not Allowed\r\n\r\n";
}
if (!isset($headers[‘host‘]) || !$this->checkHost($headers[‘host‘])) {
$handshakeResponse = "HTTP/1.1 400 Bad Request";
}
if (!isset($headers[‘upgrade‘]) || strtolower($headers[‘upgrade‘]) != ‘websocket‘) {
$handshakeResponse = "HTTP/1.1 400 Bad Request";
}
if (!isset($headers[‘connection‘]) || strpos(strtolower($headers[‘connection‘]), ‘upgrade‘) === FALSE) {
$handshakeResponse = "HTTP/1.1 400 Bad Request";
}
if (!isset($headers[‘sec-websocket-key‘])) {
$handshakeResponse = "HTTP/1.1 400 Bad Request";
}
else {
}
if (!isset($headers[‘sec-websocket-version‘]) || strtolower($headers[‘sec-websocket-version‘]) != 13) {
$handshakeResponse = "HTTP/1.1 426 Upgrade Required\r\nSec-WebSocketVersion: 13";
}
if (($this->headerOriginRequired && !isset($headers[‘origin‘]) ) || ($this->headerOriginRequired && !$this->checkOrigin($headers[‘origin‘]))) {
$handshakeResponse = "HTTP/1.1 403 Forbidden";
}
if (($this->headerSecWebSocketProtocolRequired && !isset($headers[‘sec-websocket-protocol‘])) || ($this->headerSecWebSocketProtocolRequired && !$this->checkWebsocProtocol($headers[‘sec-websocket-protocol‘]))) {
$handshakeResponse = "HTTP/1.1 400 Bad Request";
}
if (($this->headerSecWebSocketExtensionsRequired && !isset($headers[‘sec-websocket-extensions‘])) || ($this->headerSecWebSocketExtensionsRequired && !$this->checkWebsocExtensions($headers[‘sec-websocket-extensions‘]))) {
$handshakeResponse = "HTTP/1.1 400 Bad Request";
}
// Done verifying the _required_ headers and optionally required headers.
if (isset($handshakeResponse)) {
socket_write($user->socket,$handshakeResponse,strlen($handshakeResponse));
$this->disconnect($user->socket);
return;
}
$user->headers = $headers;
$user->handshake = $buffer;
$webSocketKeyHash = sha1($headers[‘sec-websocket-key‘] . $magicGUID);
$rawToken = "";
for ($i = 0; $i < 20; $i++) {
$rawToken .= chr(hexdec(substr($webSocketKeyHash,$i*2, 2)));
}
$handshakeToken = base64_encode($rawToken) . "\r\n";
$subProtocol = (isset($headers[‘sec-websocket-protocol‘])) ? $this->processProtocol($headers[‘sec-websocket-protocol‘]) : "";
$extensions = (isset($headers[‘sec-websocket-extensions‘])) ? $this->processExtensions($headers[‘sec-websocket-extensions‘]) : "";
$handshakeResponse = "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: $handshakeToken$subProtocol$extensions\r\n";
socket_write($user->socket,$handshakeResponse,strlen($handshakeResponse));
$this->connected($user);
}
客户端
socket.onopen = function(msg) { }
接受和发送信息：
服务器端
在进行通信之前要对数据帧解码/编码才能获取/发送客户端信息。
握手过程代码都集中在 function doHandshake （）中。
数据侦编码代码如下：
/*数据帧编码
@param string 原始信息
@param obj 用户对象
@param string 消息类型
@param boolean 是否为附加数据
return string 经过编码的数据
*/
protected function frame($message, $user, $messageType=‘text‘, $messageContinues=false) {
switch ($messageType) {
case ‘continuous‘: //附加数据帧
$b1 = 0;
break;
case ‘text‘: //文本数据帧
$b1 = ($user->sendingContinuous) ? 0 : 1;
break;
case ‘binary‘: //二进制数据帧
$b1 = ($user->sendingContinuous) ? 0 : 2;
break;
case ‘close‘: //连接关闭
$b1 = 8;
break;
case ‘ping‘:
$b1 = 9;
break;
case ‘pong‘:
$b1 = 10;
break;
}
if ($messageContinues) {
$user->sendingContinuous = true;
}
else {
$b1 += 128;
$user->sendingContinuous = false;
}
$length = strlen($message);
$lengthField = "";
if ($length < 126) {
$b2 = $length;
}
elseif ($length < 65536) {
$b2 = 126;
$hexLength = dechex($length);
//$this->stdout("Hex Length: $hexLength");
if (strlen($hexLength)%2 == 1) {
$hexLength = ‘0‘ . $hexLength;
}
$n = strlen($hexLength) - 2;
for ($i = $n; $i >= 0; $i=$i-2) {
$lengthField = chr(hexdec(substr($hexLength, $i, 2))) . $lengthField;
}
while (strlen($lengthField) < 2) {
$lengthField = chr(0) . $lengthField;
}
}
else {
$b2 = 127;
$hexLength = dechex($length);
if (strlen($hexLength)%2 == 1) {
$hexLength = ‘0‘ . $hexLength;
}
$n = strlen($hexLength) - 2;
for ($i = $n; $i >= 0; $i=$i-2) {
$lengthField = chr(hexdec(substr($hexLength, $i, 2))) . $lengthField;
}
while (strlen($lengthField) < 8) {
$lengthField = chr(0) . $lengthField;
}
}
return chr($b1) . chr($b2) . $lengthField . $message;
}
数据帧解码如下：
/*数据帧解码
@param string 原始数据帧
@param obj 用户实体
return string 用户端返回的数据
*/
protected function deframe($message, &$user) {
//echo $this->strtohex($message);
$headers = $this->extractHeaders($message);
$pongReply = false;
$willClose = false;
switch($headers[‘opcode‘]) {
case 0:
case 1:
case 2:
break;
case 8:
// todo: close the connection
$user->hasSentClose = true;
return "";
case 9:
$pongReply = true;
case 10:
break;
default:
//$this->disconnect($user); // todo: fail connection
$willClose = true;
break;
}
/* Deal by split_packet() as now deframe() do only one frame at a time.
if ($user->handlingPartialPacket) {
$message = $user->partialBuffer . $message;
$user->handlingPartialPacket = false;
return $this->deframe($message, $user);
}
*/
if ($this->checkRSVBits($headers,$user)) {
return false;
}
if ($willClose) {
// todo: fail the connection
return false;
}
$payload = $user->partialMessage . $this->extractPayload($message,$headers);
if ($pongReply) {
$reply = $this->frame($payload,$user,‘pong‘);
socket_write($user->socket,$reply,strlen($reply));
return false;
}
if ($headers[‘length‘] > strlen($this->applyMask($headers,$payload))) {
$user->handlingPartialPacket = true;
$user->partialBuffer = $message;
return false;
}
$payload = $this->applyMask($headers,$payload);
if ($headers[‘fin‘]) {
$user->partialMessage = "";
return $payload;
}
$user->partialMessage = $payload;
return false;
}
针对上述过程可以参考参考http://www.qixing318.com/article/643129914.html这篇文章，很详细。
客户端：
客户端相对来说简单一些，接受信息方法为 socket.onmessage，发送消息为 socket.send 方法。
总结：以原来那个需求来说，websocket是有点大材小用了，还是老老实实轮询来的方便和实际。。。。。。。
时间： 2024-12-06 09:07:52