php websocket device server

wsds.php

#!/usr/bin/php
<?php
/* websocket/device server program for raspberry pi
 * this program only deals with packets that are 125 bytes max
 * currently only one client can connect at a time. Maybe not a bad thing.
 * run as super user (for gpio access)
 * check out https://gist.github.com/BobBurns/6f83930912da4094f014 for the client html code

 * much of the juicy bits adapted from ghedipunk/PHP-Websockets
 * 
 * commands to send to client:
 * 0xA0 0x00 device A power state off
 * 0xA0 0x01          power state on
 * 0xA0 0x02          power state sleep
 * 0xA1 0xXX 0xXX     sensor 1 value
 * 0xA2 0xXX 0xXX     sensor 2 value
 * 0xA3 0xXX 0xXX     sensor 3 value
 * 0xA4 0xXX 0xXX     sensor 4 value
 * 
 * 0xB0 0x00 device B power state off
 * 0xB0 0x01          power state on
 * 0xB0 0x02          power state sleep
 * 0xB1 0xXX 0xXX     sensor 1 value
 * 0xB2 0xXX 0xXX     sensor 2 value
 * 0xB3 0xXX 0xXX     sensor 3 value
 * 0xB4 0xXX 0xXX     sensor 4 value

 * commands sent to server
 * 0x00 disconnect
 * 0x10 power off device A
 * 0x11 power on  device A
 * 0x12 sleep device A
 * 0x13 0xXX 0xXX inc by value bus 1 device A
 * 0x14 0xXX 0xXX dec by value bus 1 
 * 0x15 0xXX 0xXX set value    bus 1
 * 0x16 0xXX 0xXX inc by value bus 2
 * 0x17 0xXX 0xXX dec by value bus 2
 * 0x18 0xXX 0xXX set value    bus 2
 *
 * 0x20 power off device B
 * 0x21 power on  device B
 * 0x22 sleep device B
 * 0x23 0xXX 0xXX inc by value bus 1 device B
 * 0x24 0xXX 0xXX dec by value bus 1 
 * 0x25 0xXX 0xXX set value    bus 1
 * 0x26 0xXX 0xXX inc by value bus 2
 * 0x27 0xXX 0xXX dec by value bus 2
 * 0x28 0xXX 0xXX set value    bus 2


*/
$errno = 0; $errstr = ''; 
$resource = ''; 
$on = false;
$maxbuf = 4096;

// open gpio pin 23 to input 24 to output
// this program has led on gpio pin 24 and a button on pin 23
system ( "echo 23 > /sys/class/gpio/export" );
system ( "echo in > /sys/class/gpio/gpio23/direction" );
system ( "echo 24 > /sys/class/gpio/export" );
system ( "echo out > /sys/class/gpio/gpio24/direction" );

$server = @stream_socket_server("tcp://0.0.0.0:2342", $errno, $errstr);
if ($server === false) {
  fwrite(STDERR, "Error: $errno: $errstr\n");
  exit(1);
}

echo "listening for connection...\n";
$result = array();
for (;;) {
  $conn = @stream_socket_accept($server, -1, $peer);
  if ($conn !== false) {
    // got connection now do handshake
    wshandshake($conn);

    $oventemp = 0x20;
    $humidity = 50;
    $on = false;
// main loop
    for (;;) {
      stream_set_blocking($conn, 0);
// get device values
      $button = array();
      exec ( "cat /sys/class/gpio/gpio23/value" , $button );
      if ($button[0] == 1) {
         printf("button pressed");
         if ($on === false) $on = true;
         else if ($on === true) $on = false;
      }

      if ($on === true)
        system( "echo 1 > /sys/class/gpio/gpio24/value" );
      else
        system( "echo 0 > /sys/class/gpio/gpio24/value" );

      if ($on === true) $message = 0x01;
      else $message = 0x00;

// send some values
      $cmd = 0xA0;              // powerstate device A
      $dataframe = setupState($cmd, $message);
      fwrite($conn, $dataframe);
      $oventemp += rand(-2,2);
      if ($oventemp > 255) $oventemp = 255;
      if ($oventemp < 0) $oventemp = 0;

      $cmd = 0xA1;              // sensor 1 device A
      $dataframe = setupValue($cmd, 0x00, $oventemp);
      fwrite($conn, $dataframe);
      $cmd = 0xA2;              // sensor 2 device A
      $dataframe = setupValue($cmd, 0x00, $humidity);
      fwrite($conn, $dataframe);
//      echo 'message successful ';

// check for incomming
      $recbuf = fread($conn, $maxbuf);
      if ($recbuf != false) {
        $result = getIncomming($recbuf);
        if ($result[0] == 0) {
          echo "Bye!";
          break;
        }
        switch ($result[0]) { // check sent command and do something with it
          case 0x10:
            // power off
            break;
          case 0x11:
            // power on
            break;
          case 0x12:
            // sleep device A
            break;
          case 0x13:
            $humidity += $result[2];
            break;
          case 0x14:
            $humidity -= $result[2];
            break;
          case 0x15:
            // etc
            break;
        }
      }
      usleep(500000);
    }
    fclose($conn);
  }
}

function wshandshake($conn) {
  global $resource;
  $MAXLEN = 4096;
  $magicGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
  $headers = array();
  if (!($buf = fread($conn, $MAXLEN))) printf("error: fread\n");
  $lines = explode("\n", $buf);
  print_r($lines);
  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", $line, $request);
        $headers['get'] = trim($request[1]);
      }
  }

  if (isset($headers['get']))
    $resource = $headers['get'];

  if (!isset($headers['sec-websocket-version']) || strtolower($headers['sec-websocket-version']) != 13) {
      $handshakeResponse = "HTTP/1.1 426 Upgrade Required\r\nSec-WebSocketVersion: 13";
      fwrite($conn, $handshakeResponse);
      return false;
    }

  $webSocketKeyHash = sha1($headers['sec-websocket-key'] . $magicGUID);
  $rawToken = "";
  for ($i = 0; $i < 20; $i++) {
    $rawToken .= chr(hexdec(substr($webSocketKeyHash,$i*2, 2)));
  }
  $handshakeToken = base64_encode($rawToken);

  $handshakeResponse = "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: $handshakeToken\r\n\r\n";

  fwrite($conn, $handshakeResponse);
  return true;
}

function setupState($cmd, $state) {
  $opcode = 0x82;
  $len = 0x02;

  return chr($opcode) . chr($len) . chr($cmd) . chr ($state);
}

function setupValue($cmd, $valH, $valL) {
  $opcode = 0x82;
  $len = 0x03;

  return chr($opcode) . chr($len) . chr($cmd) . chr($valH) . chr($valL);

}

function setupPacket($message) {
  $opcode = 0x81;               // to send text
  $length = strlen($message);
  print_r($length);
  $extendedLength = "";

  if ($length < 126) {
    $paylen = dechex($length);
  }

  return chr($opcode) . chr($paylen) . $message;
}

function getIncomming($inbuf) {
  $decoded = array();
  $arrayBuffer = unpack('C*', $inbuf);
  $opcode = $arrayBuffer[1] & 0x0F;
  $paylen = $arrayBuffer[2] & 0x7F;
  $maskbit = $arrayBuffer[2] & 0x80;
  
  if ($opcode == 0x08) {
    $decoded[0] = 0;
    return $decoded;
  }

  if ($maskbit > 0) {
    $mask = array($arrayBuffer[3], $arrayBuffer[4], $arrayBuffer[5], $arrayBuffer[6]);
    for ($i = 0; $i < $paylen; $i++) {
      $decoded[$i] = $arrayBuffer[7+$i] ^ $mask[$i % 4];
    }
  }
  return $decoded;
}


?>