<?php

class PHPSocketServer

{

  const ERROR = 0;

  const LOG   = 1;

  const DEBUG = 2;

  private $aConfig       = NULL;

  private $hSocket       = NULL;

  private $aClients      = array();

  private $iRunning      = 0;

  private $iStartTime    = 0;

  private $iLastActivity = 0;

  private static $aDefaults = array

  (

    'main' => array

    (

      'address'          => 'localhost',

      'port'             => 15151,

      'backlog'          => 200,

      'select_timeout'   => 1,

      'pid_file'         => 'phpserver.pid'

    ),

    'verbosity' => array

    (

      'echo_log'         => 1,

      'echo_debug'       => 0,

      'echo_errors'      => 1,

      'log_errors'       => 1

    )

  );

  public function getPidFile()

  {

    return $this->aConfig['main']['pid_file'];

  }

  private static function getName( $hSocket )

  {

    return socket_getpeername( $hSocket, $sAddress, $iPort ) ? "$sAddress:$iPort" : "?????:???";

  }

  private function log( $sMessage, $iType )

  {

    $sTimeStamp = @strftime( '%c' );

    if( $iType == self::ERROR )

    {

      $aBacktrace = debug_backtrace();

      $aBacktrace = $aBacktrace[1];

      $sMessage   = sprintf( '[%s] [E] %s%s%s [%d] : %s', $sTimeStamp, $aBacktrace['class'], $aBacktrace['type'], $aBacktrace['function'], $aBacktrace['line'], $sMessage );

      if( $this->aConfig['verbosity']['echo_errors'] )

        printf( "$sMessage\n" );

      if( $this->aConfig['verbosity']['log_errors'] )

        error_log( $sMessage );

    }

    else if( $iType == self::DEBUG && $this->aConfig['verbosity']['echo_debug'] )

    {

      echo sprintf( '[%s] [D] : %s', $sTimeStamp, $sMessage )."\n";

    }

    else if( $iType == self::LOG && $this->aConfig['verbosity']['echo_log'] )

    {

      echo sprintf( '[%s] [L] : %s', $sTimeStamp, $sMessage )."\n";

    }

  }

  /*

   * Handle clients here.

   */

  private function handleClientRequest( $hClient, $iClientIndex )

  {

    /*

     * ...

     */

    $this->disconnect( $iClientIndex );

  }

  private function disconnect( $i )

  {

    socket_close( $this->aClients[ $i ] );

    $this->aClients[ $i ] = NULL;

  }

  private function loadConfiguration( $sConfigFile )

  {

    if( !is_file( $sConfigFile ) || !is_readable( $sConfigFile ) )

      die( "Could not read $sConfigFile.\n" );

    else if( !( $this->aConfig = parse_ini_file( $sConfigFile, TRUE ) ) )

      die( "Could not parse $sConfigFile.\n" );

    foreach( self::$aDefaults as $sSection => $aDefaultValues )

    {

      if( !isset( $this->aConfig[ $sSection ] ) )

        $this->aConfig[ $sSection ] = array();

      foreach( $aDefaultValues as $sName => $sValue )

      {

        if( !isset( $this->aConfig[ $sSection ][ $sName ] ) )

          $this->aConfig[ $sSection ][ $sName ] = $sValue;

      }

    }

  }

  public function setConfig( $sSectionName, $sConfigName, $mValue )

  {

    if( !isset( $this->aConfig[ $sSectionName ] ) )

      $this->aConfig[ $sSectionName ] = array();

    $this->aConfig[ $sSectionName ][ $sConfigName ] = $mValue;

  }

  public function __construct( $sConfigFile )

  {

    $this->loadConfiguration( $sConfigFile );

    if( !( $this->hSocket = socket_create( AF_INET, SOCK_STREAM, SOL_TCP ) ) )

      $this->log( 'Could not create main socket ( '.socket_strerror( socket_last_error() ).' ).', self::ERROR );

    else if( socket_set_option( $this->hSocket, SOL_SOCKET, SO_REUSEADDR, 1 ) === FALSE )

      $this->log( 'Could not set SO_REUSEADDR flag ( '.socket_strerror( socket_last_error() ).' ).', self::ERROR );

  }

  public function start()

  {

    if( !socket_bind( $this->hSocket, $this->aConfig['main']['address'], $this->aConfig['main']['port'] ) )

      $this->log( 'Could not bind on '.$this->aConfig['main']['address'].':'.$this->aConfig['main']['port'].' ( '.socket_strerror( socket_last_error() ).' ).', self::ERROR );

    else if( !socket_listen( $this->hSocket, $this->aConfig['main']['backlog'] ) )

      $this->log( 'Could not put main socket in listening mode ( '.socket_strerror( socket_last_error() ).' ).', self::ERROR );

    else if( !socket_set_nonblock( $this->hSocket ) )

      $this->log( 'Could not set main socket in non-blocking mode ( '.socket_strerror( socket_last_error() ).' ).', self::ERROR );

    else

    {

      $this->iStartTime = time();

      $this->log( 'Server started on '.$this->aConfig['main']['address'].':'.$this->aConfig['main']['port'].' .', self::LOG );

      for(;;)

      {

        $aRead = array_merge( array( $this->hSocket ), $this->aClients );

        if( socket_select( $aRead, $aWrite, $aExcept, $this->aConfig['main']['select_timeout'] ) )

        {

          if( in_array( $this->hSocket, $aRead ) )

          {

            if( ( $hClient = @socket_accept( $this->hSocket ) ) )

            {

              $this->aClients[ microtime(TRUE) ] = $hClient;

              $this->iLastActivity = time();

              $this->log( 'New incoming connection '.self::getName( $hClient ), self::DEBUG );

            }

            else

              $this->log( 'Could not accept a new connection ( '.socket_strerror( socket_last_error() ).' ).', self::ERROR );

          }

        }

        /*

         * Search for readable clients.

         */

        foreach( $this->aClients as $i => $hClient )

        {

          if( in_array( $hClient, $aRead ) )

          {

            $this->handleClientRequest( $hClient, $i );

          }

        }

        /*

         * Remove closed connections.

         */

        $this->aClients = array_filter( $this->aClients );

      }

    }

  }

  public function __destruct()

  {

    if( $this->hSocket )

    {

      $this->log( 'Shutting down ...', self::LOG );

      foreach( $this->aClients as $sId => $hClient )

      {

        if( $hClient )

          socket_close( $hClient );

      }

      socket_close( $this->hSocket );

    }

    @unlink( $this->getPidFile() );

  }

}

?>