Asked  7 Months ago    Answers:  5   Viewed   39 times

I am looking for a simple code to create a WebSocket server. I found phpwebsockets but it is outdated now and doesn't support the newest protocol. I tried updating it myself but it doesn't seem to work.

#!/php -q
<?php  /*  >php -q server.php  */

error_reporting(E_ALL);
set_time_limit(0);
ob_implicit_flush();

$master  = WebSocket("localhost",12345);
$sockets = array($master);
$users   = array();
$debug   = false;

while(true){
  $changed = $sockets;
  socket_select($changed,$write=NULL,$except=NULL,NULL);
  foreach($changed as $socket){
    if($socket==$master){
      $client=socket_accept($master);
      if($client<0){ console("socket_accept() failed"); continue; }
      else{ connect($client); }
    }
    else{
      $bytes = @socket_recv($socket,$buffer,2048,0);
      if($bytes==0){ disconnect($socket); }
      else{
        $user = getuserbysocket($socket);
        if(!$user->handshake){ dohandshake($user,$buffer); }
        else{ process($user,$buffer); }
      }
    }
  }
}

//---------------------------------------------------------------
function process($user,$msg){
  $action = unwrap($msg);
  say("< ".$action);
  switch($action){
    case "hello" : send($user->socket,"hello human");                       break;
    case "hi"    : send($user->socket,"zup human");                         break;
    case "name"  : send($user->socket,"my name is Multivac, silly I know"); break;
    case "age"   : send($user->socket,"I am older than time itself");       break;
    case "date"  : send($user->socket,"today is ".date("Y.m.d"));           break;
    case "time"  : send($user->socket,"server time is ".date("H:i:s"));     break;
    case "thanks": send($user->socket,"you're welcome");                    break;
    case "bye"   : send($user->socket,"bye");                               break;
    default      : send($user->socket,$action." not understood");           break;
  }
}

function send($client,$msg){
  say("> ".$msg);
  $msg = wrap($msg);
  socket_write($client,$msg,strlen($msg));
}

function WebSocket($address,$port){
  $master=socket_create(AF_INET, SOCK_STREAM, SOL_TCP)     or die("socket_create() failed");
  socket_set_option($master, SOL_SOCKET, SO_REUSEADDR, 1)  or die("socket_option() failed");
  socket_bind($master, $address, $port)                    or die("socket_bind() failed");
  socket_listen($master,20)                                or die("socket_listen() failed");
  echo "Server Started : ".date('Y-m-d H:i:s')."n";
  echo "Master socket  : ".$master."n";
  echo "Listening on   : ".$address." port ".$port."nn";
  return $master;
}

function connect($socket){
  global $sockets,$users;
  $user = new User();
  $user->id = uniqid();
  $user->socket = $socket;
  array_push($users,$user);
  array_push($sockets,$socket);
  console($socket." CONNECTED!");
}

function disconnect($socket){
  global $sockets,$users;
  $found=null;
  $n=count($users);
  for($i=0;$i<$n;$i++){
    if($users[$i]->socket==$socket){ $found=$i; break; }
  }
  if(!is_null($found)){ array_splice($users,$found,1); }
  $index = array_search($socket,$sockets);
  socket_close($socket);
  console($socket." DISCONNECTED!");
  if($index>=0){ array_splice($sockets,$index,1); }
}

function dohandshake($user,$buffer){
  console("nRequesting handshake...");
  console($buffer);
  //list($resource,$host,$origin,$strkey1,$strkey2,$data) 
  list($resource,$host,$u,$c,$key,$protocol,$version,$origin,$data) = getheaders($buffer);
  console("Handshaking...");

    $acceptkey = base64_encode(sha1($key . "258EAFA5-E914-47DA-95CA-C5AB0DC85B11",true));
  $upgrade  = "HTTP/1.1 101 Switching ProtocolsrnUpgrade: websocketrnConnection: UpgradernSec-WebSocket-Accept: $acceptkeyrn";

  socket_write($user->socket,$upgrade,strlen($upgrade));
  $user->handshake=true;
  console($upgrade);
  console("Done handshaking...");
  return true;
}

function getheaders($req){
    $r=$h=$u=$c=$key=$protocol=$version=$o=$data=null;
    if(preg_match("/GET (.*) HTTP/"   ,$req,$match)){ $r=$match[1]; }
    if(preg_match("/Host: (.*)rn/"  ,$req,$match)){ $h=$match[1]; }
    if(preg_match("/Upgrade: (.*)rn/",$req,$match)){ $u=$match[1]; }
    if(preg_match("/Connection: (.*)rn/",$req,$match)){ $c=$match[1]; }
    if(preg_match("/Sec-WebSocket-Key: (.*)rn/",$req,$match)){ $key=$match[1]; }
    if(preg_match("/Sec-WebSocket-Protocol: (.*)rn/",$req,$match)){ $protocol=$match[1]; }
    if(preg_match("/Sec-WebSocket-Version: (.*)rn/",$req,$match)){ $version=$match[1]; }
    if(preg_match("/Origin: (.*)rn/",$req,$match)){ $o=$match[1]; }
    if(preg_match("/rn(.*?)$/",$req,$match)){ $data=$match[1]; }
    return array($r,$h,$u,$c,$key,$protocol,$version,$o,$data);
}

function getuserbysocket($socket){
  global $users;
  $found=null;
  foreach($users as $user){
    if($user->socket==$socket){ $found=$user; break; }
  }
  return $found;
}

function     say($msg=""){ echo $msg."n"; }
function    wrap($msg=""){ return chr(0).$msg.chr(255); }
function  unwrap($msg=""){ return substr($msg,1,strlen($msg)-2); }
function console($msg=""){ global $debug; if($debug){ echo $msg."n"; } }

class User{
  var $id;
  var $socket;
  var $handshake;
}

?>

and the client:

var connection = new WebSocket('ws://localhost:12345');
connection.onopen = function () {
  connection.send('Ping'); // Send the message 'Ping' to the server
};

// Log errors
connection.onerror = function (error) {
  console.log('WebSocket Error ' + error);
};

// Log messages from the server
connection.onmessage = function (e) {
  console.log('Server: ' + e.data);
};

If there is anything wrong in my code can you help me fix it? Concole in firefox says

Firefox can't establish a connection to the server at ws://localhost:12345/.

 Answers

49

I was in the same boat as you recently, and here is what I did:

  1. I used the phpwebsockets code as a reference for how to structure the server-side code. (You seem to already be doing this, and as you noted, the code doesn't actually work for a variety of reasons.)

  2. I used PHP.net to read the details about every socket function used in the phpwebsockets code. By doing this, I was finally able to understand how the whole system works conceptually. This was a pretty big hurdle.

  3. I read the actual WebSocket draft. I had to read this thing a bunch of times before it finally started to sink in. You will likely have to go back to this document again and again throughout the process, as it is the one definitive resource with correct, up-to-date information about the WebSocket API.

  4. I coded the proper handshake procedure based on the instructions in the draft in #3. This wasn't too bad.

  5. I kept getting a bunch of garbled text sent from the clients to the server after the handshake and I couldn't figure out why until I realized that the data is encoded and must be unmasked. The following link helped me a lot here: (original link broken) Archived copy.

    Please note that the code available at this link has a number of problems and won't work properly without further modification.

  6. I then came across the following SO thread, which clearly explains how to properly encode and decode messages being sent back and forth: How can I send and receive WebSocket messages on the server side?

    This link was really helpful. I recommend consulting it while looking at the WebSocket draft. It'll help make more sense out of what the draft is saying.

  7. I was almost done at this point, but had some issues with a WebRTC app I was making using WebSocket, so I ended up asking my own question on SO, which I eventually solved: What is this data at the end of WebRTC candidate info?

  8. At this point, I pretty much had it all working. I just had to add some additional logic for handling the closing of connections, and I was done.

That process took me about two weeks total. The good news is that I understand WebSocket really well now and I was able to make my own client and server scripts from scratch that work great. Hopefully the culmination of all that information will give you enough guidance and information to code your own WebSocket PHP script.

Good luck!


Edit: This edit is a couple of years after my original answer, and while I do still have a working solution, it's not really ready for sharing. Luckily, someone else on GitHub has almost identical code to mine (but much cleaner), so I recommend using the following code for a working PHP WebSocket solution:
https://github.com/ghedipunk/PHP-Websockets/blob/master/websockets.php


Edit #2: While I still enjoy using PHP for a lot of server-side related things, I have to admit that I've really warmed up to Node.js a lot recently, and the main reason is because it's better designed from the ground up to handle WebSocket than PHP (or any other server-side language). As such, I've found recently that it's a lot easier to set up both Apache/PHP and Node.js on your server and use Node.js for running the WebSocket server and Apache/PHP for everything else. And in the case where you're on a shared hosting environment in which you can't install/use Node.js for WebSocket, you can use a free service like Heroku to set up a Node.js WebSocket server and make cross-domain requests to it from your server. Just make sure if you do that to set your WebSocket server up to be able to handle cross-origin requests.

Wednesday, March 31, 2021
 
mcography
answered 7 Months ago
48

Not with PHP, but with Javascript. PHP is a server-side language, all the code is processed before your browser gets the HTML.

Try using this code:

<html>
<head>
<title>Dynamic Form</title>
<script language="javascript">
var i = 1;
function changeIt()
{

my_div.innerHTML = my_div.innerHTML +"<br><input type='text' name='mytext'+ i>"
i++;
}
</script>
</head>
<body>

<form name="form" action="post" method="">
<input type="text" name=t1>
<input type="button" value="test" onClick="changeIt()">
<div id="my_div"></div>

</body>
Wednesday, March 31, 2021
 
Asher
answered 7 Months ago
16

Make city_a index completely different from city_b index so it is easy to check.

// generate a two-dimensional matrix in here
$distMatrix = array();

foreach($tableRows as $cityDist) {
    $from = $cityDist['id_city_a'];
    $to = $cityDist['id_city_b'];
    $dist = $cityDist['distance'];

    $distMatrix[$from][$to] = $dist;
}

Display as an HTML Table...

echo '<table border="1">';
echo '<tr>';
echo '<td>', '#', '</td>';
foreach(array_keys(current($distMatrix)) as $city_b) { // city_b headings
   echo '<td>', $city_b ,'</td>';
}
echo '</tr>';

foreach(array_keys($distMatrix) as $city_a) { // need the city_a as row index
    echo '<tr>';
    echo '<td>', $city_a, '</td>'; // city_a ad
    foreach(array_keys($distMatrix[$city_a]) as $city_b) { // need the city_b as column index
        echo '<td>', $distMatrix[$city_a][$city_b], '</td>'; // distance from the matrix;
    }
    echo '</tr>';
}
echo '</table>';

Test data - used data from @ashkufaraz

// changed the city ids so we can easily see city_a and city_b
$tableRows[0]=array("id"=>1, "id_city_a"=>1, "id_city_b"=>11, "distance"=>0);
$tableRows[1]=array("id"=>2, "id_city_a"=>1, "id_city_b"=>12, "distance"=>8);
$tableRows[2]=array("id"=>3, "id_city_a"=>1, "id_city_b"=>13, "distance"=>6);
$tableRows[3]=array("id"=>4, "id_city_a"=>2, "id_city_b"=>11, "distance"=>8);
$tableRows[4]=array("id"=>5, "id_city_a"=>2, "id_city_b"=>12, "distance"=>0);
$tableRows[5]=array("id"=>6, "id_city_a"=>2, "id_city_b"=>13, "distance"=>9);
$tableRows[6]=array("id"=>7, "id_city_a"=>3, "id_city_b"=>11, "distance"=>6);
$tableRows[7]=array("id"=>8, "id_city_a"=>3, "id_city_b"=>12, "distance"=>9);
$tableRows[8]=array("id"=>9, "id_city_a"=>3, "id_city_b"=>13, "distance"=>0);

Output:

#   11  12  13
1   0   8   6
2   8   0   9
3   6   9   0
Saturday, May 29, 2021
 
edsk
answered 5 Months ago
89

No, it's not possible to have UDP communication within JavaScript. Sorry.

Saturday, July 31, 2021
 
Jonesome Reinstate Monica
answered 3 Months ago
70

If you're sending a test message >125 bytes but <65536, your problem might be caused by a faulty format string to pack. I think this one should be 'CCn' (your current code writes the 2 bytes of the length in the wrong order).

If that doesn't help, you could try some client-side logging:

  • Does the onopen callback run to prove that the initial handshake completed successfully?
  • Do the onerror or onclose callbacks run, either after connection or after your server sends its message?
Thursday, August 19, 2021
 
Marco Pierucci
answered 2 Months ago
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