<?php
// $Id: mimedetect.module,v 1.6 2008-07-21 22:00:14 drewish Exp $

/**
 * @file
 * Provide server side mime type detection.
 *
 * @author Darrel O'Pry, http://www.drupal.org/user/22202
 * @copyright Copyright(c) 2007, Darrel O'Pry
 */


function mimedetect_menu() {
  $items = array();

  // The admin settings form.
  $items['admin/settings/mimedetect'] = array(
    'title' => 'Mime type detection',
    'description' => 'Control how the mime type of uploaded files will be determined.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('mimedetect_settings'),
    'access arguments' => array('administer site configuration'),
  );

  return $items;
}


function mimedetect_settings() {
  $form = array();
  $form['mimedetect_enable_file_binary'] = array(
    '#type' => 'checkbox',
    '#title' => t("Use UNIX 'file' command to detect mime type?"),
    '#description' => t("The UNIX 'file' command will be used for mime detection only if the PHP Fileinfo extension is not installed or fails to load."),
    '#default_value' => variable_get('mimedetect_enable_file_binary', FALSE),
  );
  $form['mimedetect_file_binary'] = array(
    '#type' => 'textfield',
    '#title' => t("Path to the 'file' command"),
    '#description' => t("The path to the executable 'file' binary."),
    '#default_value' => variable_get('mimedetect_file_binary','/usr/bin/file'),
  );
  return system_settings_form($form);
}

function mimedetect_settings_validate($form_id, &$form_state) {
  // Test file binary settings.
  if ($form_state['values']['mimedetect_enable_file_binary']) {
    if (empty($form_state['values']['mimedetect_file_binary'])) {
      form_set_error('mimedetect_file_binary', t("You must specify the path to the 'file' binary if it is enabled."));
    }
    if (!is_executable($form_state['values']['mimedetect_file_binary'])) {
      if (!file_exists($form_state['values']['mimedetect_file_binary'])) {
        form_set_error('mimedetect_file_binary', t("The path %path does not exist or is not readable by your webserver.", array('%path' => $form_state['values']['mimedetect_file_binary'])));
      }
      else {
        form_set_error('mimedetect_file_binary', t("%path is not executable by your webserver.", array('%path' => $form_state['values']['mimedetect_file_binary'])));
      }
    }
  }
}

/**
 * Detect File Mime Type.
 *
 * @param $file A standard Drupal file object. The filepath property is used to
 *   locate the file and if the mime detection fails, the mimetype property is
 *   returned.
 * @return String containing the file's MIME type.
 */
function mimedetect_mime($file) {
  $file = (object)$file;

  // Lookup array, just in case we can't figure out the mime type.
  static $extension_mimes = array(
    // MS ASF derived multimedia filetypes
    'asx' => 'video/x-ms-asf',
    'wma' => 'audio/x-ms-wma',
    'wax' => 'audio/x-ms-wax',
    'wmv' => 'video/x-ms-wmv',
    'wvx' => ' video/x-ms-wvx',
    'wm'  => 'video/x-ms-wm',
    'wmx' => 'video/x-ms-wmx',
    'wmz' => 'application/x-ms-wmz',
    'wmd' => 'application/x-ms-wmd',

    // Standard audio types
    'au' => 'audio/basic',
    'snd' => 'audio/basic',
    'mid' => 'audio/mid',
    'rmi' => 'audio/mid',
    'mp3' => 'audio/mpeg',
    'aif' => 'audio/x-aiff',
    'aifc' => 'audio/x-aiff',
    'aidff' => 'audio/x-aiff',
    'm3u' => 'audio/x-mpegurl',
    'ra'  => 'audio/x-pn-realaudio',
    'ram' => 'audio/x-pn-realaudio',
    'wav' => 'audio/x-wav',

    // Standard image types
    'bmp' => 'image/bmp',
    'cod' => 'image/cis-cod',
    'gif' => 'image/gif',
    'ief' => 'image/ief',
    'jpe' => 'image/jpeg',
    'jpg' => 'image/jpeg',
    'jpeg' => 'image/jpeg',
    'jfif' => 'image/pipeg',
    'png' => 'image/png',
    'svg' => 'image/svg+xml',
    'tif' => 'image/tiff',
    'tiff' => 'image/tiff',
    'ras' => 'image/x-cmu-raster',
    'cmx' => 'image/x-cmx',
    'ico' => 'image/x-ico', // as in the freedesktop.org MIME info database - IANA prefers 'image/vnd.microsoft.icon'
    'pnm' => 'image/x-portable-anymap',
    'pbm' => 'image/x-portable-bitmap',
    'pgm' => 'image/x-portable-graymap',
    'ppm' => 'image/x-portable-pixmap',
    'rgb' => 'image/x-rgb',
    'xbm' => 'image/x-xbitmap',
    'xpm' => 'image/x-xpixmap',
    'xwd' => 'image/x-xwindowdump',

    // Standard video types
    'mp2' => 'video/mpeg',
    'mpa' => 'video/mpeg',
    'mpe' => 'video/mpeg',
    'mpeg' => 'video/mpeg',
    'mpg' => 'video/mpeg',
    'mpv2' => 'video/mpeg',
    'mov' => 'video/quicktime',
    'qt'  => 'video/quicktime',
    'lsf' => 'video/x-la-asf',
    'lsx' => 'video/x-la-asf',
    'asf' => 'video/x-ms-asf',
    'asr' => 'video/x-ms-asf',
    'asx' => 'video/x-ms-asf',
    'avi' => 'video/x-msvideo',
    'movie' => 'video/x-sgi-movie',
  );

  $mime = FALSE;

  // Try to use the fileinfo extension first.
  if (extension_loaded('fileinfo')) {
    static $finfo = FALSE;
    if ($finfo || $finfo = @finfo_open(FILEINFO_MIME, drupal_get_path('module', 'mimedetect') .'/magic')) {
      $mime = finfo_file($finfo, $file->filepath);
    }
  }

  // Try the 'file' binary.
  if (!$mime && ($filebin = variable_get('mimedetect_file_binary', '/usr/bin/file')) && is_executable($filebin)) {
    // On OSX the -i switch is -I, so if we use the long flags everyone is
    // happy. I checked back to version 3.41 and it still supports the long
    // names but if you run into problems you can use " -bi ".
    $command = $filebin .' --brief --mime '. escapeshellarg($file->filepath);
    $mime = trim(exec($command, $out));
    // with text we often get charset like 'text/plain; charset=us-ascii'
    $mime = split(';', $mime);
    $mime = trim($mime[0]);
  }

  // Trust the browser...  ack!
  if (!$mime) {
    $mime = $file->filemime;
  }

  // ASF derived media formats are hard to detect with magic. They're
  // typically all reported as video/x-ms-asf or application/octet-stream
  // These aren't really informative about the media type, so we attempt to
  // figure it out by extension.
  // I expect OGG to present similar difficulties in determining how it should be played...

  if (!$mime || $mime == 'application/octet-stream') {
    $parts = explode('.', $file->filename);
    $extension = array_pop($parts);
    if (isset($extension_mimes[$extension])) {
      $mime = $extension_mimes[$extension];
    }
    else {
      $mime = 'application/octet-stream';
    }
  }

  return $mime;
}