websocket_client.php

<?php
/*----------------------------------------------------------------------------*\
  Websocket client - https://github.com/paragi/PHP-websocket-client

  By Paragi 2013, Simon Riget MIT license.

  This is a demonstration of a websocket clinet.

  If you find flaws in it, please let me know at simon.riget (at) gmail

  Websockets use hybi10 frame encoding:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-------+-+-------------+-------------------------------+
       |F|R|R|R| opcode|M| Payload len |    Extended payload length    |
       |I|S|S|S|  (4)  |A|     (7)     |             (16/63)           |
       |N|V|V|V|       |S|             |   (if payload len==126/127)   |
       | |1|2|3|       |K|             |                               |
       +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
       |     Extended payload length continued, if payload len == 127  |
       + - - - - - - - - - - - - - - - +-------------------------------+
       |                               |Masking-key, if MASK set to 1  |
       +-------------------------------+-------------------------------+
       | Masking-key (continued)       |          Payload Data         |
       +-------------------------------- - - - - - - - - - - - - - - - +
       :                     Payload Data continued ...                :
       + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
       |                     Payload Data continued ...                |
       +---------------------------------------------------------------+

  See: https://tools.ietf.org/rfc/rfc6455.txt
  or:  http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-10#section-4.2

\*----------------------------------------------------------------------------*/

/*============================================================================*\
  Open websocket connection

  resource websocket_open(string $host [,int $port [,$additional_headers [,string &error_string ,[, int $timeout]]]]

  host
    A host URL. It can be a domain name like www.example.com or an IP address,
    with port number. Local host example: 127.0.0.1:8080

  port

  headers (optional)
    additional HTTP headers to attach to the request.
    For example to parse a session cookie: "Cookie: SID=" . session_id()

  error_string (optional)
    A referenced variable to store error messages, i any

  timeout (optional)
    The maximum time in seconds, a read operation will wait for an answer from
    the server. Default value is 10 seconds.

  ssl (optional)  

  persistant (optional)

  path (optional)

  Context (optional)


  Open a websocket connection by initiating a HTTP GET, with an upgrade request
  to websocket.
  If the server accepts, it sends a 101 response header, containing
  "Sec-WebSocket-Accept"
\*============================================================================*/
function websocket_open($host='',$port=80,$headers='',&$error_string='',$timeout=10,$ssl=false, $persistant = false, $path = '/', $context = null){

  // Generate a key (to convince server that the update is not random)
  // The key is for the server to prove it i websocket aware. (We know it is)
  $key=base64_encode(openssl_random_pseudo_bytes(16));

  $header = "GET " . $path . " HTTP/1.1\r\n"
    ."Host: $host\r\n"
    ."pragma: no-cache\r\n"
    ."Upgrade: WebSocket\r\n"
    ."Connection: Upgrade\r\n"
    ."Sec-WebSocket-Key: $key\r\n"
    ."Sec-WebSocket-Version: 13\r\n";

  // Add extra headers
  if(!empty($headers)) foreach($headers as $h) $header.=$h."\r\n";

  // Add end of header marker
  $header.="\r\n";

  // Connect to server
  $host = $host ? $host : "127.0.0.1";
  $port = $port <1 ? ( $ssl ? 443 : 80 ): $port;
  $address = ($ssl ? 'ssl://' : '') . $host . ':' . $port;
  
  $flags = STREAM_CLIENT_CONNECT | ( $persistant ? STREAM_CLIENT_PERSISTENT : 0 );
  $ctx = $context ?? stream_context_create ();
  $sp = stream_socket_client($address, $errno, $errstr, $timeout, $flags, $ctx);
  
  if(!$sp){
    $error_string = "Unable to connect to websocket server: $errstr ($errno)";
    return false;
  }

  // Set timeouts
  stream_set_timeout($sp,$timeout);

  if (!$persistant or ftell($sp) === 0) {

    //Request upgrade to websocket
    $rc = fwrite($sp,$header);
    if(!$rc){
      $error_string
        = "Unable to send upgrade header to websocket server: $errstr ($errno)";
      return false;
    }

    // Read response into an assotiative array of headers. Fails if upgrade failes.
    $reaponse_header=fread($sp, 1024);

    // status code 101 indicates that the WebSocket handshake has completed.
    if (stripos($reaponse_header, ' 101 ') === false
      || stripos($reaponse_header, 'Sec-WebSocket-Accept: ') === false) {
      $error_string = "Server did not accept to upgrade connection to websocket."
        .$reaponse_header. E_USER_ERROR;
      return false;
    }
    // The key we send is returned, concatenate with "258EAFA5-E914-47DA-95CA-
    // C5AB0DC85B11" and then base64-encoded. one can verify if one feels the need...

  }
  return $sp;
}

/*============================================================================*\
  Write to websocket

  int websocket_write(resource $handle, string $data ,[boolean $final])

  Write a chunk of data through the websocket, using hybi10 frame encoding

  handle
    the resource handle returned by websocket_open, if successful

  data
    Data to transport to server

  final (optional)
    indicate if this block is the final data block of this request. Default true

  binary (optional)
    indicate if this block is sent in binary or text mode.  Default true/binary
\*============================================================================*/
function websocket_write($sp,$data,$final=true,$binary=true){
  // Assemble header: FINal 0x80 | Mode (0x02 binary, 0x01 text)

  if ($binary)
      $header=chr(($final?0x80:0) | 0x02); // 0x02 binary mode
  else
      $header=chr(($final?0x80:0) | 0x01); // 0x01 text mode

  // Mask 0x80 | payload length (0-125)
  if(strlen($data)<126) $header.=chr(0x80 | strlen($data));
  elseif (strlen($data)<0xFFFF) $header.=chr(0x80 | 126) . pack("n",strlen($data));
  else $header.=chr(0x80 | 127) . pack("N",0) . pack("N",strlen($data));

  // Add mask
  $mask=pack("N",rand(1,0x7FFFFFFF));
  $header.=$mask;

  // Mask application data.
  for($i = 0; $i < strlen($data); $i++)
    $data[$i]=chr(ord($data[$i]) ^ ord($mask[$i % 4]));

  return fwrite($sp,$header.$data);
}

/*============================================================================*\
  Read from websocket

  string websocket_read(resource $handle [,string &error_string])

  read a chunk of data from the server, using hybi10 frame encoding

  handle
    the resource handle returned by websocket_open, if successful

  error_string (optional)
    A referenced variable to store error messages, i any

  Read

  Note:
    - This implementation waits for the final chunk of data, before returning.
    - Reading data while handling/ignoring other kind of packages
 \*============================================================================*/
function websocket_read($sp,&$error_string=NULL){
  $data="";

  do{
    // Read header
    $header=fread($sp,2);
    if(!$header){
      $error_string = "Reading header from websocket failed.";
      return false;
    }

    $opcode = ord($header[0]) & 0x0F;
    $final = ord($header[0]) & 0x80;
    $masked = ord($header[1]) & 0x80;
    $payload_len = ord($header[1]) & 0x7F;

    // Get payload length extensions
    $ext_len = 0;
    if($payload_len >= 0x7E){
      $ext_len = 2;
      if($payload_len == 0x7F) $ext_len = 8;
      $header=fread($sp,$ext_len);
      if(!$header){
        $error_string = "Reading header extension from websocket failed.";
        return false;
      }

      // Set extented paylod length
      $payload_len= 0;
      for($i=0;$i<$ext_len;$i++)
        $payload_len += ord($header[$i]) << ($ext_len-$i-1)*8;
    }

    // Get Mask key
    if($masked){
      $mask=fread($sp,4);
      if(!$mask){
        $error_string = "Reading header mask from websocket failed.";
        return false;
      }
    }

    // Get payload
    $frame_data='';
    do{
      $frame= fread($sp,$payload_len);
      if(!$frame){
        $error_string = "Reading from websocket failed.";
        return false;
      }
      $payload_len -= strlen($frame);
      $frame_data.=$frame;
    }while($payload_len>0);

    // Handle ping requests (sort of) send pong and continue to read
    if($opcode == 9){
      // Assamble header: FINal 0x80 | Opcode 0x0A + Mask on 0x80 with zero payload
      fwrite($sp,chr(0x8A) . chr(0x80) . pack("N", rand(1,0x7FFFFFFF)));
      continue;

    // Close
    } elseif($opcode == 8){
      fclose($sp);

    // 0 = continuation frame, 1 = text frame, 2 = binary frame
    }elseif($opcode < 3){
      // Unmask data
      $data_len=strlen($frame_data);
      if($masked)
        for ($i = 0; $i < $data_len; $i++)
          $data.= $frame_data[$i] ^ $mask[$i % 4];
      else
        $data.= $frame_data;

    }else
      continue;

  }while(!$final);

  return $data;
}
?>