<?php

/**

 * Webserver class

 * 

 * Greyhound - real web management for Amarok

 * Copyright (C) 2008 Dan Fuhry

 *

 * This program is Free Software; you can redistribute and/or modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied

 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.

 */

/**

 * Version of the server

 * @const string

 */

define('HTTPD_VERSION', '0.1b1');

/**

 * Simple web server written in PHP.

 * @package Amarok

 * @subpackage WebControl

 * @author Dan Fuhry

 * @license Public domain

 */

class WebServer

{

  /**

   * IP address we're bound to

   * @var string

   */

  var $bind_address = '127.0.0.1';

  /**

   * Socket resource

   * @var resource

   */

  var $sock = null;

  /**

   * Server string

   * @var string

   */

  var $server_string = 'PhpHttpd';

  /**

   * Default document (well default handler)

   * @var string

   */

  var $default_document = false;

  /**

   * HTTP response code set by the handler function

   * @var int

   */

  var $response_code = 0;

  /**

   * Content type set by the current handler function

   * @var string

   */

  var $content_type = '';

  /**

   * Response headers to send back to the client

   * @var array

   */

  var $response_headers = array();

  /**

   * List of handlers

   * @var array

   */

  var $handlers = array();

  /**

   * Switch to control if directory listing is enabled

   * @var bool

   */

  var $allow_dir_list = false;

  /**

   * Constructor.

   * @param string IPv4 address to bind to

   * @param int Port number

   */

  function __construct($address = '127.0.0.1', $port = 8080)

  {

    @set_time_limit(0);

    @ini_set('memory_limit', '256M');

    // do we have socket functions?

    if ( !function_exists('socket_create') )

    {

      burnout('System does not support socket functions. Please rebuild your PHP or install an appropriate extension.');

    }

    $this->sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));

    if ( !$this->sock )

      throw new Exception('Could not create socket');

    $result = socket_bind($this->sock, $address, $port);

    if ( !$result )

      throw new Exception("Could not bind to $address:$port");

    $result = socket_listen($this->sock, SOMAXCONN);

    if ( !$result )

      throw new Exception("Could not listen for connections $address:$port");

    $this->bind_address = $address;

    $this->server_string = "PhpHttpd/" . HTTPD_VERSION . " PHP/" . PHP_VERSION . "\r\n";

  }

  /**

   * Destructor.

   */

  function __destruct()

  {

    status('WebServer: destroying socket');

    @socket_close($this->sock);

  }

  /**

   * Main server loop

   */

  function serve()

  {

    while ( true )

    {

      // wait for connection...

      // trick from http://us.php.net/manual/en/function.socket-accept.php

      $remote = false;

      switch(@socket_select($r = array($this->sock), $w = array($this->sock), $e = array($this->sock), 5)) {

        case 2:

          break;

        case 1:

          $remote = @socket_accept($this->sock);

          break;

        case 0:

          break;

      }

      if ( !$remote )

      {

        continue;

      }

      // read request

      $last_line = '';

      $client_headers = '';

      while ( $line = @socket_read($remote, 1024, PHP_NORMAL_READ) )

      {

        $line = str_replace("\r", "", $line);

        if ( empty($line) )

          continue;

        if ( $line == "\n" && $last_line == "\n" )

          break;

        $client_headers .= $line;

        $last_line = $line;

      }

      // parse request

      $client_headers = trim($client_headers);

      $client_headers = explode("\n", $client_headers);

      // first line

      $request = $client_headers[0];

      if ( !preg_match('/^(GET|POST) \/([^ ]*) HTTP\/1\.[01]$/', $request, $match) )

      {

        $this->send_http_error($remote, 400, 'Your client issued a malformed or illegal request.');

        continue;

      }

      $method =& $match[1];

      $uri =& $match[2];

      // set client headers

      unset($client_headers[0]);

      foreach ( $client_headers as $line )

      {

        if ( !preg_match('/^([A-z0-9-]+): (.+)$/is', $line, $match) )

          continue;

        $key = 'HTTP_' . strtoupper(str_replace('-', '_', $match[1]));

        $_SERVER[$key] = $match[2];

      }

      if ( isset($_SERVER['HTTP_AUTHORIZATION']) )

      {

        $data = $_SERVER['HTTP_AUTHORIZATION'];

        $data = substr(strstr($data, ' '), 1);

        $data = base64_decode($data);

        $_SERVER['PHP_AUTH_USER'] = substr($data, 0, strpos($data, ':'));

        $_SERVER['PHP_AUTH_PW'] = substr(strstr($data, ':'), 1);

      }

      $postdata = '';

      $_POST = array();

      if ( $method == 'POST' )

      {

        // read POST data

        if ( isset($_SERVER['HTTP_CONTENT_LENGTH']) )

        {

          $postdata = socket_read($remote, intval($_SERVER['HTTP_CONTENT_LENGTH']), PHP_BINARY_READ);

        }

        else

        {

          $postdata = socket_read($remote, 8388608, PHP_NORMAL_READ);

        }

        if ( preg_match_all('/(^|&)([a-z0-9_\.\[\]-]+)(=[^ &]+)?/', $postdata, $matches) )

        {

          if ( isset($matches[1]) )

          {

            foreach ( $matches[0] as $i => $_ )

            {

              $_POST[$matches[2][$i]] = ( !empty($matches[3][$i]) ) ? urldecode(substr($matches[3][$i], 1)) : true;

            }

          }

        }

      }

      // parse URI

      $params = '';

      if ( strstr($uri, '?') )

      {

        $params = substr(strstr($uri, '?'), 1);

        $uri    = substr($uri, 0, strpos($uri, '?'));

      }

      $_SERVER['REQUEST_URI'] = '/' . rawurldecode($uri);

      $_SERVER['REQUEST_METHOD'] = $method;

      socket_getpeername($remote, $_SERVER['REMOTE_ADDR'], $_SERVER['REMOTE_PORT']);

      $_GET = array();

      if ( preg_match_all('/(^|&)([a-z0-9_\.\[\]-]+)(=[^ &]+)?/', $params, $matches) )

      {

        if ( isset($matches[1]) )

        {

          foreach ( $matches[0] as $i => $_ )

          {

            $_GET[$matches[2][$i]] = ( !empty($matches[3][$i]) ) ? urldecode(substr($matches[3][$i], 1)) : true;

          }

        }

      }

      if ( $uri == '' )

      {

        $uri = strval($this->default_document);

      }

      $uri_parts = explode('/', $uri);

      // loop through URI parts, see if a handler is set

      $handler = false;

      for ( $i = count($uri_parts) - 1; $i >= 0; $i-- )

      {

        $handler_test = implode('/', $uri_parts);

        if ( isset($this->handlers[$handler_test]) )

        {

          $handler = $this->handlers[$handler_test];

          $handler['id'] = $handler_test;

          break;

        }

        unset($uri_parts[$i]);

      }

      if ( !$handler )

      {

        $this->send_http_error($remote, 404, "The requested URL /$uri was not found on this server.");

        continue;

      }

      $this->send_standard_response($remote, $handler, $uri, $params);

      @socket_close($remote);

    }

  }

  /**

   * Sends the client appropriate response headers.

   * @param resource Socket connection to client

   * @param int HTTP status code, defaults to 200

   * @param string Content type, defaults to text/html

   * @param string Additional headers to send, optional

   */                     

  function send_client_headers($socket, $http_code = 200, $contenttype = 'text/html', $headers = '')

  {

    global $http_responses;

    $reason_code = ( isset($http_responses[$http_code]) ) ? $http_responses[$http_code] : 'Unknown';

    status("{$_SERVER['REMOTE_ADDR']} {$_SERVER['REQUEST_METHOD']} {$_SERVER['REQUEST_URI']} $http_code {$_SERVER['HTTP_USER_AGENT']}");

    $headers = str_replace("\r\n", "\n", $headers);

    $headers = str_replace("\n", "\r\n", $headers);

    $headers = preg_replace("#[\r\n]+$#", '', $headers);

    @socket_write($socket, "HTTP/1.1 $http_code $reason_code\r\n");

    @socket_write($socket, "Server: $this->server_string");

    @socket_write($socket, "Connection: close\r\n");

    @socket_write($socket, "Content-Type: $contenttype\r\n");

    if ( !empty($headers) )

    {

      @socket_write($socket, "$headers\r\n");

    }

    @socket_write($socket, "\r\n");

  }

  /**

   * Sends a normal response

   * @param resource Socket connection to client

   * @param array Handler

   */

  function send_standard_response($socket, $handler)

  {

    switch ( $handler['type'] )

    {

      case 'dir':

        // security

        $uri = str_replace("\000", '', $_SERVER['REQUEST_URI']);

        if ( preg_match('#(\.\./|\/\.\.)#', $uri) || strstr($uri, "\r") || strstr($uri, "\n") )

        {

          $this->send_http_error($socket, 403, 'Access to this resource is forbidden.');

        }

        // import mimetypes

        global $mime_types;

        // trim handler id from uri

        $uri = substr($uri, strlen($handler['id']) + 1);

        // get file path

        $file_path = rtrim($handler['dir'], '/') . $uri;

        if ( file_exists($file_path) )

        {

          // found it :-D

          // is this a directory?

          if ( is_dir($file_path) )

          {

            if ( !$this->allow_dir_list )

            {

              $this->send_http_error($socket, 403, "Directory listing is not allowed.");

              return true;

            }

            // yes, list contents

            $root = '/' . $handler['id'] . rtrim($uri, '/');

            $parent = substr($root, 0, strrpos($root, '/')) . '/';

            $contents = <<<EOF

<html>

  <head>

    <title>Index of: $root</title>

  </head>

  <body>

    <h1>Index of $root</h1>

    <ul>

      <li><a href="$parent">Parent directory</a></li>

EOF;

            $dirs = array();

            $files = array();

            $d = @opendir($file_path);

            while ( $dh = readdir($d) )

            {

              if ( $dh == '.' || $dh == '..' )

                continue;

              if ( is_dir("$file_path/$dh") )

                $dirs[] = $dh;

              else

                $files[] = $dh;

            }

            asort($dirs);

            asort($files);

            foreach ( $dirs as $dh )

            {

              $contents .= '  <li><a href="' . $root . '/' . $dh . '">' . $dh . '/</a></li>' . "\n    ";

            }

            foreach ( $files as $dh )

            {

              $contents .= '  <li><a href="' . $root . '/' . $dh . '">' . $dh . '</a></li>' . "\n    ";

            }

            $contents .= "\n    </ul>\n    <address>Served by {$this->server_string}</address>\n</body>\n</html>\n\n";

            $sz = strlen($contents);

            $this->send_client_headers($socket, 200, 'text/html', "Content-length: $sz\r\n");

            @socket_write($socket, $contents);

            return true;

          }

          // try to open the file

          $fh = @fopen($file_path, 'r');

          if ( !$fh )

          {

            // can't open it, send a 404

            $this->send_http_error($socket, 404, "The requested URL " . htmlspecialchars($_SERVER['REQUEST_URI']) . " was not found on this server.");

          }

          // get size

          $sz = filesize($file_path);

          // mod time

          $time = date('r', filemtime($file_path));

          // all good, send headers

          $fileext = substr($file_path, strrpos($file_path, '.') + 1);

          $mimetype = ( isset($mime_types[$fileext]) ) ? $mime_types[$fileext] : 'application/octet-stream';

          $this->send_client_headers($socket, 200, $mimetype, "Content-length: $sz\r\nLast-Modified: $time\r\n");

          // send body

          while ( $blk = @fread($fh, 768000) )

          {

            @socket_write($socket, $blk);

          }

          fclose($fh);

          return true;

        }

        else

        {

          $this->send_http_error($socket, 404, "The requested URL " . htmlspecialchars($_SERVER['REQUEST_URI']) . " was not found on this server.");

        }

        break;

      case 'file':

        // import mimetypes

        global $mime_types;

        // get file path

        $file_path = $handler['file'];

        if ( file_exists($file_path) )

        {

          // found it :-D

          // is this a directory?

          if ( is_dir($file_path) )

          {

            $this->send_http_error($socket, 500, "Host script mapped a directory as a file entry.");

            return true;

          }

          // try to open the file

          $fh = @fopen($file_path, 'r');

          if ( !$fh )

          {

            // can't open it, send a 404

            $this->send_http_error($socket, 404, "The requested URL " . htmlspecialchars($_SERVER['REQUEST_URI']) . " was not found on this server.");

          }

          // get size

          $sz = filesize($file_path);

          // mod time

          $time = date('r', filemtime($file_path));

          // all good, send headers

          $fileext = substr($file_path, strrpos($file_path, '.') + 1);

          $mimetype = ( isset($mime_types[$fileext]) ) ? $mime_types[$fileext] : 'application/octet-stream';

          $this->send_client_headers($socket, 200, $mimetype, "Content-length: $sz\r\nLast-Modified: $time\r\n");

          // send body

          while ( $blk = @fread($fh, 768000) )

          {

            @socket_write($socket, $blk);

          }

          fclose($fh);

          return true;

        }

        else

        {

          $this->send_http_error($socket, 404, "The requested URL " . htmlspecialchars($_SERVER['REQUEST_URI']) . " was not found on this server.");

        }

        break;

      case 'function':

        // init vars

        $this->content_type = 'text/html';

        $this->response_code = 200;

        $this->response_headers = array();

        // error handling

        @set_error_handler(array($this, 'function_error_handler'), E_ALL);

        try

        {

          ob_start();

          $result = @call_user_func($handler['function'], $this);

          $output = ob_get_contents();

          ob_end_clean();

        }

        catch ( Exception $e )

        {

          restore_error_handler();

          $this->send_http_error($socket, 500, "A handler crashed with an exception; see the command line for details.");

          status("caught exception in handler {$handler['id']}:\n$e");

          return true;

        }

        restore_error_handler();

        // the handler function should return this magic string if it writes its own headers and socket data

        if ( $output == '__break__' )

        {

          return true;

        }

        $headers = implode("\r\n", $this->response_headers);

        // write headers

        $this->send_client_headers($socket, $this->response_code, $this->content_type, $headers);