WebSocket is a feature of HTML5 for establishing socket connections between a web browser and a Server. Once connection has been established with the server, all WebSocket data (frames) are sent directly over a socket rather than usual HTTP response and requests, giving us a much faster and persistent communication between a web browser and a server.
Implementation:
Server: Server is a daemon (that runs in background) using nothing but PHP. In server file, we create a PHP socket which states listening to the clients on a specified port. Server accepts incoming Clients and map their socket ID’s with a unique Client ID in order to send/receive data to and from a specific client.
Client: Client creates a web socket request to server domain and port. After handshake, a persistent connection is established. Client can receive anything sent from the server on real time basis, no need to further request server for updates.
Advantages:
- Instant data passing between server and clients
- Server can push data to any client
- Faster communication between server and clients
- No server overloading with Ajax
.
Sample Code:
At Server Side:
Command to run Server file is as follows:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 | php -q \path-to-server\server.php $host = 'cr/chat'; //host $port = '9001'; //port $null = NULL; //null var //Create TCP/IP sream socket $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP); //reuseable port socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1); //bind socket to specified host socket_bind($socket, 0, $port); //listen to port socket_listen($socket); $cc=array(); //create & add listning socket to the list $clients = array($socket); //start endless loop, so that our script doesn't stop while (true) { //manage multipal connections<br> $changed = $clients; //returns the socket resources in $changed array socket_select($changed, $null, $null, 0, 10); //check for new socket if (in_array($socket, $changed)) { $socket_new = socket_accept($socket); //accpet new socket $clients[] = $socket_new; //add socket to client array $header = socket_read($socket_new, 1024); //read data sent by the socket perform_handshaking($header, $socket_new, $host, $port); //perform websocket handshake socket_getpeername($socket_new, $ip); //get ip address of connected socket //make room for new socket $found_socket = array_search($socket, $changed); unset($changed[$found_socket]); } //loop through all connected sockets foreach ($changed as $changed_socket) { //check for any incomming data while(socket_recv($changed_socket, $buf, 1024, 0) >= 1) { $received_text = unmask($buf); //unmask data $tst_msg = json_decode($received_text); //json decode if($tst_msg->type=='system') { $cc[$tst_msg->id]=array(); $cc[$tst_msg->id]['name']=$tst_msg->name; $cc[$tst_msg->id]['soc_id']=$changed_socket; $response_text =mask(json_encode(array('type'=>'system', 'message'=>'Initial message received'))); send_message($response_text,$changed_socket); //send data } else { $user_name = $tst_msg->name; //sender name $user_message = $tst_msg->message; //message text $user_color = $tst_msg->color; //color if(isset($cc[$tst_msg->to_id])) { $to_sock=$cc[$tst_msg->to_id]['soc_id']; //prepare data to be sent to client $response_text = mask(json_encode(array('type'=>'usermsg', 'name'=>$user_name, 'message'=>$user_message, 'color'=>$user_color))); send_message($response_text,$to_sock); //send data } } break 2; //exist this loop } $buf = @socket_read($changed_socket, 1024, PHP_NORMAL_READ); if ($buf === false) { // check disconnected client // remove client for $clients array $found_socket = array_search($changed_socket, $clients); socket_getpeername($changed_socket, $ip); unset($clients[$found_socket]); //notify all users about disconnected connection $response = mask(json_encode(array('type'=>'system', 'message'=>$ip.' disconnected'))); //send_message($response); } } } // close the listening socket socket_close($sock); function send_message($msg,$client_socket) { @socket_write($client_socket,$msg,strlen($msg)); return true; } //Unmask incoming framed message function unmask($text) { $length = ord($text[1]) & 127; if($length == 126) { $masks = substr($text, 4, 4); $data = substr($text, 8); } elseif($length == 127) { $masks = substr($text, 10, 4); $data = substr($text, 14); } else { $masks = substr($text, 2, 4); $data = substr($text, 6); } $text = ""; for ($i = 0; $i < strlen($data); ++$i) { $text .= $data[$i] ^ $masks[$i%4]; } return $text; } //Encode message for transfer to client. function mask($text) { $b1 = 0x80 | (0x1 & 0x0f); $length = strlen($text); if($length <= 125) $header = pack('CC', $b1, $length); elseif($length > 125 && $length < 65536) $header = pack('CCn', $b1, 126, $length); elseif($length >= 65536) $header = pack('CCNN', $b1, 127, $length); return $header.$text; } //handshake new client. function perform_handshaking($receved_header,$client_conn, $host, $port) { $headers = array(); $lines = preg_split("/\r\n/", $receved_header); foreach($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'))); //hand shaking header $upgrade = "HTTP/1.1 101 Web Socket Protocol Handshake\r\n" . "Upgrade: websocket\r\n" . "Connection: Upgrade\r\n" . "WebSocket-Origin: $host\r\n" . "WebSocket-Location: ws://$host:$port/server.php\r\n". "Sec-WebSocket-Accept:$secAccept\r\n\r\n"; socket_write($client_conn,$upgrade,strlen($upgrade)); } |
At Client Side:
Command to run at client side is as follows:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | $(document).ready(function(){ //create a new WebSocket object. var wsUri = "ws://cr:9001/chat/server.php:9000"; websoc2.Client Side ket = new WebSocket(wsUri); websocket.onopen = function(ev) { // connection is open $('#message_box').append("<div class=\"system_msg\">Connected!</div>"); //notify user //prepare json data var msg = { type:'system', id: 7, projectId:2424, na2.Client Side me:'mks' }; //convert and send data to server websocket.send(JSON.stringify(msg)); } $('#send-b2.Client Side tn').click(function(){ //use clicks message send button var mymessage = $('#message').val(); //get message text var myname = $('#name').val(); //get user name if(myname == ""){ //empty name? alert("Enter your Name please!"); return; } if(mymessage == ""){ //emtpy message? alert("Enter Some message Please!"); return; } //prepare json data var msg = { message: mymessage, type:'user', name: 'mks', id: 7, projectId:2424, to_id:5, color : '<?php echo $colours[$user_colour]; ?>' }; //convert and send data to server websocket.send(JSON.stringify(msg)); $('#message_box').append("<div><span class=\"user_name\" style=\"color:#F00\">"+myname+"</span> : <span class=\"user_message\">"+mymessage+"</span></div>"); }); |
Comments are closed.