<?php
/** DomFramework
  * @package domframework
  * @author Dominique Fournier <dominique@fournier38.fr>
  */

/** This class allow to start a TCP server and call a function each time a
  * client is connected on it. Each client is separated in a child, so the
  * server allow to have multiple simultaneous connections.
  *
  * The handler method or function will get one parameter : the client from
  * socket_accept. It will allow to use socket_getpeername to get the peer
  * address and port, socket_read to get the data from the client,
  * socket_write to write on the client, socket_shutdown ($client) and
  *  socket_close ($client) to finish the connection
  *
  * The server has a child limit set to 500 connections by default
  */
class tcpserver
{
  ////////////////////
  //   PROPERTIES   //
  ////////////////////
  // {{{
  /** Allow to debug with messages on screen
    */
  private $debug = false;
  /** Store the data concerning the sockets and the handlers
    */
  private $handlers = array ();
  /** Store the addresses
    */
  private $addresses = array ();
  /** Store the ports
    */
  private $ports = array ();
  /** The max number of children. The maximum of concurrent connections
    */
  private $maxChild = 500;
  /** The timeout if not used a channel
    */
  private $timeout = 30;
  /** Set to true in parent, and false in child
    */
  private $parent = true;
  /** The socket in the child
    */
  private $socket = null;
  /** Read in Text mode or in Binary mode
    */
  private $readMode = "text";
  /** Stop the new connections
    */
  private $loopStop = false;
  /** The number of active clients
    */
  private $nbChild = 0;
  /** The PID number when loop in background is active
    */
  private $pidLoopInBackground;
  /** Server name displayed in process list
    */
  private $processName = "tcpserver";
  // }}}

  ////////////////////////
  //   PUBLIC METHODS   //
  ////////////////////////
  /** The constructor add the error handler needed to catch the error on
    * stream_select () when the process is killed
    */
  public function __construct ()
  // {{{
  {
    $this->logDebug ("NEW OBJECT CONSTRUCTED");
    set_error_handler([$this, 'errorHandler']);
  }
  // }}}

  /** The destructor is a log for debug
    */
  public function __destruct ()
  // {{{
  {
    $this->logDebug ("Object destructed");
  }
  // }}}

  /** Set/get the max children, the maximum of concurrent connections
    * @param integer|null $val The number of child to get/set
    */
  final public function maxChild ($val = null)
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($val === null)
      return $this->maxChild;
    $this->maxChild = intval ($val);
    return $this;
  }
  // }}}

  /** Set/get the read mode : text or binary
    * @param string|null $val The mode to set (or get if null)
    */
  final public function readMode ($val = null)
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($val === null)
      return $this->readMode;
    if ($val !== "text" && $val !== "binary")
      throw new \Exception ("Invalid readMode provided (nor text nor binary)",
        500);
    $this->readMode = $val;
    return $this;
  }
  // }}}

  /** Set the process name displayed in system
    * @param string|null $val The name of the process to set (or get if null)
    */
  final public function processName ($val = null)
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($val === null)
      return $this->processName;
    $this->processName = $val;
    return $this;
  }
  // }}}

  /** Set the timeout for open communication without any data transmited.
    * @param string|null $val The number of seconds to set (or get if null)
    */
  final public function timeout ($val = null)
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($val === null)
      return $this->timeout;
    if (! is_int ($val))
      throw new \Exception (dgettext ("domframework",
        "tcpserver : invalid timeout provided : not integer value"), 500);
    if ($val <= 0)
      throw new \Exception (dgettext ("domframework",
        "tcpserver : invalid timeout provided : negatif or null value"), 500);
    $this->timeout = intval ($val);
    return $this;
  }
  // }}}

  /** Set the address, port and handler that will be enabled by loop
    * @param string $address The server address (can be 0.0.0.0 for all IPv4
    * interfaces or :: for all the IPv4 and IPv6 interfaces)
    * @param integer $port The port to listen
    * @param callable $handler The handler that will be called when a client is
    * connected to the address:port
    */
  final public function init ($address, $port, $handler)
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    $this->nbChild = 0;
    $this->handlers["$address:$port"] = $handler;
    $this->addresses[] = $address;
    $this->ports[] = $port;
    return $this;
  }
  // }}}

  /** Start the main loop after the init and keep in it until loopStop
    */
  final public function loop ()
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if (empty ($this->addresses))
      throw new \Exception (dgettext ("domframework",
      "Can not start TCP server loop without addresses initialized"), 500);
    if (empty ($this->ports))
      throw new \Exception (dgettext ("domframework",
      "Can not start TCP server loop without port initialized"), 500);
    foreach ($this->ports as $port)
    {
      if ($port < 1024 && posix_getuid() !== 0)
        throw new \Exception (dgettext ("domframework",
        "Can not start TCP server on port $port without root user"), 500);
    }
    $this->logDebug ("Initialize the signal managers");
    //declare (ticks = 1);
    pcntl_async_signals (true);
    pcntl_signal (SIGCHLD, [$this, "sigCHLD"]);
    pcntl_signal (SIGTERM, [$this, "sigTERMINT"]);
    pcntl_signal (SIGINT, [$this, "sigTERMINT"]);
    cli_set_process_title ($this->processName." main");
    foreach ($this->addresses as $key => $address)
    {
      $port = $this->ports[$key];
      if (filter_var ($address, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4))
        $address = "$address";
      elseif (filter_var ($address, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6))
        $address = "[$address]";
      else
        throw new \Exception ("Can't create socket : invalid address provided");
      $sockServer[$key] = stream_socket_server ("tcp://$address:$port",
        $errno, $errstr);
      if ($sockServer[$key] === false)
      {
        throw new \Exception ("Can't create socket : $errstr");
      }
      stream_set_timeout ($sockServer[$key], $this->timeout);
      $this->logDebug ("Listening on $address:$port...");
    }
    $ppid = posix_getppid ();
    while (1)
    {
      if (posix_getppid () !== $ppid)
      {
        $this->logDebug ("PARENT PID change : ".posix_getppid () .
          " !== $ppid : STOP");
        exit;
      }
      if ($this->loopStop)
      {
        $this->logDebug ("Do not accept new connections ($this->nbChild)");
        foreach ($sockServer as $socket)
          stream_socket_shutdown ($socket, STREAM_SHUT_RD);
        if ($this->nbChild === 0)
        {
          $this->logDebug ("No more childs and loopStop requested".
            " : end of process");
          exit;
        }
        sleep (2);
        continue;
      }
      $read = $sockServer;
      $write = null;
      $except = null;
      // catch the errors, as a kill on a pending stream_select display a PHP
      // Warning
      if (@stream_select ($read, $write, $except, 0, 200000) < 1)
      {
        pcntl_signal_dispatch ();
        continue;
      }
      foreach ($read as $sock)
      {
        $client = stream_socket_accept ($sock);
        $name = stream_socket_get_name ($client, false);
        $pos = strrpos ($name, ":");
        $localPort = substr ($name, $pos+1);
        $localAddress = substr ($name, 0, $pos);
        $name = stream_socket_get_name ($client, true);
        $pos = strrpos ($name, ":");
        $port = substr ($name, $pos+1);
        $address = substr ($name, 0, $pos);
        $handlerAddress = $localAddress;
        if (! key_exists ("$handlerAddress:$localPort", $this->handlers))
        {
          // If the address of the handler doesn't exists, the socket is maybe
          // waiting on all the interfaces addresses
          $handlerAddress = str_replace (["[", "]"], ["",""], $handlerAddress);
          if (filter_var ($handlerAddress, FILTER_VALIDATE_IP,
            FILTER_FLAG_IPV4))
            $handlerAddress = "0.0.0.0";
          elseif (filter_var ($handlerAddress, FILTER_VALIDATE_IP,
            FILTER_FLAG_IPV6))
            $handlerAddress = "::";
          if (! key_exists ("$handlerAddress:$localPort", $this->handlers))
          {
            printf ("Can't find the handler for %s:%d\n", $handlerAddress,
                    $localPort);
            continue;
          }
        }
        if (substr ($address, 0, 8) === "[::ffff:")
          $address = substr ($address, 8, -1);
        if (substr ($localAddress, 0, 7) === "[::ffff:")
          $localAddress = substr ($localAddress, 8, -1);
        $this->logDebug ("New connection $address:$port > ".
            "$localAddress:$localPort : ".
            "use handler $handlerAddress:$localPort");
        $handler = $this->handlers["$handlerAddress:$localPort"];
        // We got a connection fork to manage it
        if ($this->nbChild > $this->maxChild)
        {
          printf ("Too much child process %d : Abort the connection !!\n",
                  $this->nbChild);
          @stream_socket_shutdown ($client, STREAM_SHUT_RDWR);
          continue;
        }
        $pid = pcntl_fork();
        if ($pid == -1)
        {
          throw new \Exception ("TCPServer can not fork", 500);
        }
        else if ($pid)
        {
          // parent process: return to the main loop
          $this->nbChild++;
          continue;
        }

        $this->logDebug ("Child start ($address:$port) : ".
            ($this->nbChild+1)." child active");
        // Do not stop if the parent is requesting a stop from Ctrl+C
        cli_set_process_title ($this->processName." ($address:$port)");
        pcntl_signal(SIGINT, SIG_IGN);
        $sid = posix_setsid();
        // In the child. Will call the handler with the actual tcpserver object
        // as parameter
        $this->parent = false;
        $this->socket = $client;
        if (is_array ($handler))
        {
          $object = $handler[0];
          $method = $handler[1];
          $object->$method ($this);
        }
        else
        {
          $function = $handler;
          $function ($this);
        }
        $this->logDebug ("Child ended ($address:$port)");
        exit;
      }
    }
  }
  // }}}

  /** Request the loop to stop. Will not allow new connections, but wait the
    * end of the existing processus
    * Block until all is closed
    */
  final public function loopStop ()
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    $this->loopStop = true;
  }
  // }}}

  /** Start the main loop in background and do not wait its end
    * @return the PID of the child
    */
  final public function loopInBackgroundStart ()
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    $this->logDebug ("Start loopInBackground");
    $pid = pcntl_fork();
    $this->pidLoopInBackground = $pid;
    if ($pid == -1)
    {
      throw new \Exception ("TCPServer can not fork in background", 500);
    }
    else if ($pid)
    {
      $this->logDebug ("loopInBackground : child = ".
          $this->pidLoopInBackground);
      // parent process: return to the main loop
      return $pid;
    }
    $sid = posix_setsid();
    // Will catch all the text messages from the application to not crash if
    // there is an "echo"
    ob_start ();
    // Catch the error messages from the application to not hang if triggered
    // An other handler can be set in function to execute
    set_error_handler ([$this, "errorHandler"]);
    set_exception_handler ([$this, "exceptionHandler"]);
    @fclose (STDIN);
    @fclose (STDOUT);
    @fclose (STDERR);
    $this->loop ();
    exit;
  }
  // }}}

  /** Stop the main loop in background and wait until its end
    */
  final public function loopInBackgroundStop ()
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    $this->logDebug ("Request loopInBackgroundStop");
    posix_kill ($this->pidLoopInBackground, SIGINT);
    pcntl_waitpid ($this->pidLoopInBackground, $status);
    $this->logDebug ("Request loopInBackgroundStop : END");
  }
  // }}}

  /** In child, get the socket to direct access
    * @return resource The socket with the client
    */
  final public function getSock ()
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($this->parent === true)
      throw new \Exception ("Can not return the socket in parent mode", 500);
    if ($this->socket === null)
      throw new \Exception ("Can not send to client : not connected", 500);
    return $this->socket;
  }
  // }}}

  /** Get an array with the peer address, peer port, local address and local
    * port
    * @return array array ("peer address", peer port, "local address", local
    * port)
    */
  final public function getInfo ()
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($this->parent === true)
      throw new \Exception ("Can not get info in parent mode", 500);
    if ($this->socket === null)
      throw new \Exception ("Can not send to client : not connected", 500);
    $name = stream_socket_get_name ($this->socket, false);
    $pos = strrpos ($name, ":");
    $localPort = substr ($name, $pos+1);
    $localAddress = substr ($name, 0, $pos);
    $name = stream_socket_get_name ($this->socket, true);
    $pos = strrpos ($name, ":");
    $port = substr ($name, $pos+1);
    $address = substr ($name, 0, $pos);
    if (substr ($address, 0, 8) === "[::ffff:")
      $address = substr ($address, 8, -1);
    if (substr ($localAddress, 0, 7) === "[::ffff:")
      $localAddress = substr ($localAddress, 8, -1);
    return array ($address, $port, $localAddress, $localPort);
  }
  // }}}

  /** Activate the SSL connection
    * Put the socket in blocking mode, as it is mandatory to have SSL connection
    * @param boolean $val True to activate, false to disable SSL
    * @param integer $cryptoMethod The cryptoMethod allowed
    */
  final public function cryptoEnable ($val,
    $cryptoMethod = STREAM_CRYPTO_METHOD_TLS_SERVER)
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($this->socket === null)
      throw new \Exception ("Can not send to server $this->ipOrName : ".
        "The server is not connected", 500);
    // Setting the options allow the IP to be decided by the connect and valid
    // the certificate of the server by the name
    $options = array ("ssl" => array (
      "verify_peer_name" => false,
    ));
    stream_set_blocking ($this->socket, true);
    stream_context_set_option ($this->socket, $options);
    return @stream_socket_enable_crypto ($this->socket, !!$val, $cryptoMethod);
  }
  // }}}

  /** Set context SSL option.
    * @param array $options The ssl array to set
    */
  final public function setSSLOptions ($options)
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($this->socket === null)
      throw new \Exception ("Can not send to server $this->ipOrName : ".
        "The server is not connected", 500);
    return stream_context_set_option ($this->socket, array ("ssl" => $options));
  }
  // }}}

  /** Send data to the client
    * @param mixed $data The data to send
    * @return the length of data sent
    */
  final public function send ($data)
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($this->parent === true)
      throw new \Exception ("Can not send data in parent mode", 500);
    if ($this->socket === null)
      throw new \Exception ("Can not send to client : not connected", 500);
    $length = strlen ($data);
    $sentLen = fwrite ($this->socket, $data);
    if ($sentLen < $length)
      throw new \Exception ("Can not send data to client", 500);
    $this->logSend ($data);
    return $sentLen;
  }
  // }}}

  /** Read the data from the client.
    * The connection must be established
    * Use the readMode in text or binary (text by default)
    * In text mode, the read return when found the first \r or the first \n.
    * @param integer $maxLength Limit the length of the data from the server
    * @return The content
    */
  final public function read ($maxLength = 1024)
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($this->parent === true)
      throw new \Exception ("Can not read data in parent mode", 500);
    if ($this->socket === null)
      throw new \Exception ("Can not read from client : not connected", 500);
    stream_set_timeout ($this->socket, $this->timeout);
    if ($this->readMode === "text")
      $read = stream_get_line ($this->socket, $maxLength, "\r\n");
    else
      $read = @fread ($this->socket, $maxLength);
    $meta = stream_get_meta_data ($this->socket);
    if (isset ($meta["timed_out"]) && $meta["timed_out"] === true)
    {
      $this->timeoutHandler();
      return false;
    }
    if ($read === false)
      throw new \Exception ("Can not read from client : ".
        error_get_last ()["message"], 500);
    $this->logReceive ($read);
    return $read;
  }
  // }}}

  /** Disconnect the socket
    */
  final public function disconnect ()
  // {{{
  {
    $this->logMethods (__METHOD__, func_get_args ());
    if ($this->parent === true)
      throw new \Exception ("Can not send data in parent mode", 500);
    if ($this->socket === null)
      throw new \Exception ("Can not disconnect client : not connected", 500);
    @stream_socket_shutdown ($this->socket, STREAM_SHUT_RDWR);
    $this->socket = null;
  }
  // }}}

  /** Log the data send to the client. By default, do nothing, but can be
    * overrided by the user
    * @param string $data The data to store in log
    */
  public function logSend ($data)
  // {{{
  {
    if (! $this->debug)
      return;
    $data = rtrim ($data)."\n";
    file_put_contents ("/tmp/debug", date ("H:i:s")." [".posix_getpid ().
    "] S> $data", FILE_APPEND);
  }
  // }}}

  /** Log the data received from the client. By default, do nothing, but can be
    * overrided by the user
    * @param string $data The data to store in log
    */
  public function logReceive ($data)
  // {{{
  {
    if (! $this->debug)
      return;
    $data = rtrim ($data)."\n";
    file_put_contents ("/tmp/debug", date ("H:i:s")." [".posix_getpid ().
    "] C> $data", FILE_APPEND);
  }
  // }}}

  /** Log the methods called. By default, do nothing, but can be overrided by
    * the user
    * @param string $method The data to store in log
    * @param mixed|null $args The data to store in log
    */
  public function logMethods ($method, $args)
  // {{{
  {
    if (! $this->debug)
      return;
    $data = $method." (";
    foreach ($args as $key => $arg)
    {
      if ($key > 0)
        $data .= ", ";
      if (is_string ($arg))
        $data .= "\"$arg\"";
      elseif (is_numeric ($arg))
        $data .= "$arg";
      elseif ($arg === false)
        $data .= "false";
      elseif ($arg === true)
        $data .= "true";
      elseif ($arg === null)
        $data .= "null";
      elseif (is_array ($arg))
        $data .= "['".implode ("','", $arg."']");
      elseif (is_object ($arg))
        $data .= "<object>";
      else
        $data .= "UNKNOWN : ".gettype ($arg);
    }
    $data.= ")\n";
    file_put_contents ("/tmp/debug", date ("H:i:s")." [".posix_getpid ().
    "] METHOD $data", FILE_APPEND);
  }
  // }}}

  /** Log the debug, By defaul do nothing, but can be overrided by the user
    * @param mixed|null $params The data to store in log
    */
  public function logDebug ($params)
  // {{{
  {
    if (! $this->debug)
      return;
    file_put_contents ("/tmp/debug", date ("H:i:s")." [".posix_getpid ().
    "] DEBUG  $params\n", FILE_APPEND);
  }
  // }}}

  /** Log the errors, By defaul do nothing, but can be overrided by the user
    * @param mixed|null $params The data to store in log
    */
  public function logError ($params)
  // {{{
  {
    if (! $this->debug)
      return;
    file_put_contents ("/tmp/debug", date ("H:i:s")." [".posix_getpid ().
    "] ERROR  $params\n", FILE_APPEND);
  }
  // }}}

  /** Error catcher.
    * By default, do nothing, but can be overrided by the user
    * @param integer $errNo The error number
    * @param string $errMsg The error message
    * @param string $file The file name
    * @param integer $line The line where the error raised
    */
  public function errorHandler ($errNo, $errMsg, $file, $line)
  // {{{
  {
    // @-operator : error suppressed
    if (0 === error_reporting())
      return false;
    $this->logError ("line $line : $errMsg");
  }
  // }}}

  /** Exception catcher
    * By default do nothing, but can be overrided by the user
    * @param object $exception The exception to catch
    */
  public function exceptionHandler ($exception)
  // {{{
  {
    $this->logError ("Exception ".$exception->getMessage () . " (".
    $exception->getFile ().":".$exception->getLine().")");
  }
  // }}}

  /** Manage the timeout exception handler
    * By default, disconnect and generate an exception
    */
  public function timeoutHandler ()
  // {{{
  {
    $this->disconnect ();
    throw new \Exception (dgettext ("domframework",
    "Disconnected for inactivity"), 500);
  }
  // }}}

  /////////////////////////
  //   PRIVATE METHODS   //
  /////////////////////////
  /** Manage the child stop signal
    */
  private function sigCHLD ()
  // {{{
  {
    $this->nbChild --;
    $this->logDebug ("One child finished : $this->nbChild childs remain ".
      "active");
    //pcntl_wait ($status, WNOHANG);
    $rc = pcntl_wait ($status);
    $this->logDebug ( "One child finished : $rc");
  }
  // }}}

  /** Manage the term / int signals
    * Will catch the stop signal, but the real end will be done when the last
    * child will be closed
    */
  private function sigTERMINT ()
  // {{{
  {
    $this->logDebug ("Request TERM/INT : Wait for last childs");
    $this->loopStop ();
  }
  // }}}
}