我们了解了常用的网络协议，今天我们来了解下socket服务。我们可以基于tcp和udp来实现我们的socket服务，
包括tcp即时通讯，udp即时通讯，websocket服务，http服务等。
我们可以通过一张图来了解socket的实现流程图。
因为我们是使用PHP语言，所以我们先来了解一下PHP的socket扩展实现。
PHP有两个socket的扩展 sockets和streams 。
sockets
socket_create(AF_INET, SOCK_STREAM, SOL_TCP)
socket_write
socket_read
socket_close
客户端
socket_connect(socket, address,
服务端
socket_bind(sock, address,
socket_listen($sock)
socket_accept
Streams
客户端
stream_socket_client
fwrite
fread
fclose($fp);
服务端
stream_socket_server
stream_set_blocking
stream_select
stream_socket_accept conn
stream_socket_recvfrom
stream_socket_sendto
stream_socket_shutdown
代码语言：javascript复制
class SocketService
{
private $address;
private $port;
private $_sockets;
public $clients;
public $maxid=1000;
public $groups;
public $groupClients;
public function __construct($address = '', $port='')
{
if(!empty($address)){
$this->address = $address;
}
if(!empty($port)) {
$this->port = $port;
}
}
public function bindUid($cliend_id,$uid){
$this->uids[$uid][$cliend_id]=$cliend_id;
}
public function sendToUid($uid,$msg){
//
$clients=$this->getClientsByUid($uid);
}
public function addGroup($groupid,$name){
}
public function joinGroup($cliend_id,$groupid){
$this->groupClients[$groupid][$cliend_id]=$cliend_id;
}
public function sendGroup($groupid,$msg){
if(!isset($this->groupClients[$groupid])){
return false;
}
$cids=$this->groupClients[$groupid];
if(!empty($cids)){
foreach($cids as $cid){
if(isset($this->$clients[$cids])){
$this->send($this->$clients[$cids],$msg);
}else{
unset($this->groupClients[$groupid]);
}
}
}
}
public function sendAll($msg){
foreach($this->clients as $kk=>$cc){
if($kk>0){
$this->send($cc, $msg);
}
}
}
public function onConnect($client_id){
echo "Client client_id:{$client_id} \n";
}
public function onMessage($client_id,$msg){
//发给所有的
$this->sendAll($msg);
}
public function onClose($client_id){
echo "$client_id close \n";
}
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);
echo "listen on $this->address $this->port ... \n";
$this->_sockets = $sock;
}
public function run(){
$this->service();
$this->clients[] = $this->_sockets;
while (true){
$changes = $this->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($_sock)) === false){
unset($this->clients[$key]);
continue;
}
$line = trim(socket_read($newClient, 1024));
echo strlen($line)."\n";
$this->handshaking($newClient, $line);
$this->maxid++;
$this->clients[$this->maxid] = $newClient;
$this->onConnect($this->maxid);
} else {
$ret=@socket_recv($_sock, $buffer, 2048, 0);
echo strlen($buffer)."\n";
if(strlen($buffer)<9){
socket_shutdown ($_sock,2);
unset($this->clients[$key]);
$this->onClose($key);
socket_clear_error();
}else{
$msg = $this->decode($buffer);
$this->onMessage($key,$msg);
}
}
}
}
}
/**
* 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));
}
/**
* 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 = $this->encode($msg);
if(false==@socket_write($newClinet, $msg, strlen($msg))){
socket_shutdown ($newClinet,2);
}
}
/**
* 解析接收数据
* @param $buffer
* @return null|string
*/
public function decode($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 $decoded;
}
/**
*打包数据
**/
public function encode($buffer) {
$first_byte="\x81";
$len=strlen($buffer);
if ($len <= 125) {
$encode_buffer = $first_byte . chr($len) . $buffer;
} else {
if ($len <= 65535) {
$encode_buffer = $first_byte . chr(126) . pack("n", $len) . $buffer;
} else {
$encode_buffer = $first_byte . chr(127) . pack("xxxxN", $len) . $buffer;
}
}
return $encode_buffer;
}
/**
* 关闭socket
*/
public function close(){
return socket_close($this->_sockets);
}
}
$sock = new SocketService('127.0.0.1','8000');
$sock->run();