islandora/MimeClass.inc

<?php
// $Id$

/**
 * @package Islandora
 * @subpackage rootdirectory
 */

/**
 *
 * This class inspired by Chris Jean's work, here:
 * http://chrisjean.com/2009/02/14/generating-mime-type-in-php-is-not-magic/
 * 
 * It does some MIME trickery, inspired by the need to to deal with Openoffice 
 * and MS Office 2007 file formats -- which are often mis-interpreted by 
 * mime-magic, fileinfo, and the *nix `file` command.
 *
 * In Drupal 6, we also make use of file_get_mimetype. See: 
 * http://api.drupal.org/api/function/file_get_mimetype/6
 * ... however this only provides a uni-directional lookup (ext->mime).
 * While I don't have a specific use case for a mime->extension lookup, I think
 * it's good to have in here.
 * 
 * Drupal 7 will have better mime handlers.  See:
 * http://api.drupal.org/api/function/file_default_mimetype_mapping/7
 *
 */

class MimeClass {
  private $private_mime_types = array(
  /**
   * This is a shortlist of mimetypes which should catch most 
   * mimetype<-->extension lookups in the context of Islandora collections.
   *
   * It has been cut from a much longer list.
   *
   * Two types of mimetypes should be put in this list:
   *  1) Special emerging formats which may not yet be expressed in the system
   *     mime.types file.
   *  2) Heavily used mimetypes of particular importance to the Islandora 
   *     project, as lookups against this list will be quicker and less 
   *     resource intensive than other methods.
   *
   * Lookups are first checked against this short list.  If no results are found,
   * then the lookup function may move on to check other sources, namely the 
   * system's mime.types file.
   *
   * In most cases though, this short list should suffice.
   * 
   * If modifying this list, please note that for promiscuous mimetypes
   * (those which map to multiple extensions, such as text/plain)
   * The function get_extension will always return the *LAST* extension in this list,
   * so you should put your preferred extension *LAST*.
   *
   * e.g... 
   * "jpeg"    => "image/jpeg",
   * "jpe"     => "image/jpeg",
   * "jpg"     => "image/jpeg",
   * 
   * $this->get_extension('image/jpeg') will always return 'jpg'.
   *
   */
    // openoffice:
    'odb'     => 'application/vnd.oasis.opendocument.database',
    'odc'     => 'application/vnd.oasis.opendocument.chart',
    'odf'     => 'application/vnd.oasis.opendocument.formula',
    'odg'     => 'application/vnd.oasis.opendocument.graphics',
    'odi'     => 'application/vnd.oasis.opendocument.image',
    'odm'     => 'application/vnd.oasis.opendocument.text-master',
    'odp'     => 'application/vnd.oasis.opendocument.presentation',
    'ods'     => 'application/vnd.oasis.opendocument.spreadsheet',
    'odt'     => 'application/vnd.oasis.opendocument.text',
    'otg'     => 'application/vnd.oasis.opendocument.graphics-template',
    'oth'     => 'application/vnd.oasis.opendocument.text-web',
    'otp'     => 'application/vnd.oasis.opendocument.presentation-template',
    'ots'     => 'application/vnd.oasis.opendocument.spreadsheet-template',
    'ott'     => 'application/vnd.oasis.opendocument.text-template',
    // staroffice:
    'stc'     => 'application/vnd.sun.xml.calc.template',
    'std'     => 'application/vnd.sun.xml.draw.template',
    'sti'     => 'application/vnd.sun.xml.impress.template',
    'stw'     => 'application/vnd.sun.xml.writer.template',
    'sxc'     => 'application/vnd.sun.xml.calc',
    'sxd'     => 'application/vnd.sun.xml.draw',
    'sxg'     => 'application/vnd.sun.xml.writer.global',
    'sxi'     => 'application/vnd.sun.xml.impress',
    'sxm'     => 'application/vnd.sun.xml.math',
    'sxw'     => 'application/vnd.sun.xml.writer',
    // k-office:
    'kil'     => 'application/x-killustrator',
    'kpt'     => 'application/x-kpresenter',
    'kpr'     => 'application/x-kpresenter',
    'ksp'     => 'application/x-kspread',
    'kwt'     => 'application/x-kword',
    'kwd'     => 'application/x-kword',
    // ms office 97:
    'doc'     => 'application/msword',
    'xls'     => 'application/vnd.ms-excel',
    'ppt'     => 'application/vnd.ms-powerpoint',
    // office2007:
    'docx'    => 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
    'docm'    => 'application/vnd.ms-word.document.macroEnabled.12',
    'dotx'    => 'application/vnd.openxmlformats-officedocument.wordprocessingml.template',
    'dotm'    => 'application/vnd.ms-word.template.macroEnabled.12',
    'xlsx'    => 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
    'xlsm'    => 'application/vnd.ms-excel.sheet.macroEnabled.12',
    'xltx'    => 'application/vnd.openxmlformats-officedocument.spreadsheetml.template',
    'xltm'    => 'application/vnd.ms-excel.template.macroEnabled.12',
    'xlsb'    => 'application/vnd.ms-excel.sheet.binary.macroEnabled.12',
    'xlam'    => 'application/vnd.ms-excel.addin.macroEnabled.12',
    'pptx'    => 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
    'pptm'    => 'application/vnd.ms-powerpoint.presentation.macroEnabled.12',
    'ppsx'    => 'application/vnd.openxmlformats-officedocument.presentationml.slideshow',
    'ppsm'    => 'application/vnd.ms-powerpoint.slideshow.macroEnabled.12',
    'potx'    => 'application/vnd.openxmlformats-officedocument.presentationml.template',
    'potm'    => 'application/vnd.ms-powerpoint.template.macroEnabled.12',
    'ppam'    => 'application/vnd.ms-powerpoint.addin.macroEnabled.12',
    'sldx'    => 'application/vnd.openxmlformats-officedocument.presentationml.slide',
    'sldm'    => 'application/vnd.ms-powerpoint.slide.macroEnabled.12',
    // wordperfect (who cares?):
    'wpd'     => 'application/wordperfect',
    // common and generic containers:
    'pdf'     => 'application/pdf',
    'eps'     => 'application/postscript',
    'ps'      => 'application/postscript',
    'rtf'     => 'text/rtf',
    'rtx'     => 'text/richtext',
    'latex'   => 'application/x-latex',
    'tex'     => 'application/x-tex',
    'texi'    => 'application/x-texinfo',
    'texinfo' => 'application/x-texinfo',
    // *ml:
    'css'     => 'text/css',
    'htm'     => 'text/html',
    'html'    => 'text/html',
    'wbxml'   => 'application/vnd.wap.wbxml',
    'xht'     => 'application/xhtml+xml',
    'xhtml'   => 'application/xhtml+xml',
    'xsl'     => 'text/xml',
    'xml'     => 'text/xml',
    'csv'     => 'text/csv',
    'tsv'     => 'text/tab-separated-values',
    'txt'     => 'text/plain',
    // images:
    "bmp"     => "image/bmp",
    "gif"     => "image/gif",
    "ief"     => "image/ief",
    "jpeg"    => "image/jpeg",
    "jpe"     => "image/jpeg",
    "jpg"     => "image/jpeg",
    "jp2"     => "image/jp2",
    "png"     => "image/png",
    "tiff"    => "image/tiff",
    "tif"     => "image/tif",
    "djvu"    => "image/vnd.djvu",
    "djv"     => "image/vnd.djvu",
    "wbmp"    => "image/vnd.wap.wbmp",
    "ras"     => "image/x-cmu-raster",
    "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-windowdump",
    // videos:
    "mpeg"    => "video/mpeg",
    "mpe"     => "video/mpeg",
    "mpg"     => "video/mpeg",
    "m4v"     => "video/mp4",
    "mp4"     => "video/mp4",
    "ogv"     => "video/ogg",
    "qt"      => "video/quicktime",
    "mov"     => "video/quicktime",
    "mxu"     => "video/vnd.mpegurl",
    "avi"     => "video/x-msvideo",
    "movie"   => "video/x-sgi-movie",
    "flv"     => "video/x-flv",
    "swf"     => "application/x-shockwave-flash",
    // audio:
    "mp3"     => "audio/mpeg",
    "mp4a"    => "audio/mp4",
    "m4a"     => "audio/mp4",
    "oga"     => "audio/ogg",
    "ogg"     => "audio/ogg",
    "flac"    => "audio/x-flac",
    "wav"     => "audio/vnd.wave",
    // compressed formats: (note: http://svn.cleancode.org/svn/email/trunk/mime.types)
    "tgz"     => "application/x-gzip",
    "gz"      => "application/x-gzip",
    "tar"     => "application/x-tar",
    "gtar"    => "application/x-gtar",
    "zip"     => "application/x-zip",
    // others: 
    'bin'     => 'application/octet-stream',
  );

  private $private_file_extensions;
  private $system_types;
  private $system_exts;
  private $etc_mime_types = '/etc/mime.types';

  public function __construct() {

    // populate the reverse shortlist:
    $this->private_file_extensions = array_flip( $this->private_mime_types );

    // pick up a local mime.types file if it is available
    if (is_readable('mime.types') ) {
      $this->etc_mime_types = 'mime.types';
    }

  }
  
  /**
   * function: getType
   * description: An alias to get_mimetype,
   * for backwards-compatibility with our old mimetype class.
   */
  public function getType( $filename ) {
    return $this->get_mimetype( $filename );
  }

  /**
   * function: get_mimetype
   * description: returns a mimetype associated with the file extension of $filename
   */
  public function get_mimetype( $filename, $debug = FALSE ) {

    $file_name_and_extension = explode( '.', $filename );
    $ext = strtolower( array_pop( $file_name_and_extension ) );
    
    if ( ! empty( $this->private_mime_types[$ext] ) ) {
      if ( TRUE === $debug )
        return array( 'mime_type' => $this->private_mime_types[$ext], 'method' => 'from_array' );
      return $this->private_mime_types[$ext];
    }
    
    if (function_exists('file_get_mimetype')) {
      $drupal_mimetype = file_get_mimetype( $filename );
      if ('application/octet-stream' != $drupal_mimetype) {
        if (TRUE == $debug)
          return array('mime_type' => $drupal_mimetype, 'method' => 'file_get_mimetype');
        return $drupal_mimetype;
      }
    }
    
    if (!isset( $this->system_types))
      $this->system_types = $this->system_extension_mime_types();
    if (isset( $this->system_types[$ext])) {
      if (TRUE == $debug)
        return array('mime_type' => $this->system_types[$ext], 'method' => 'mime.types');
      return $this->system_types[$ext];
    }
    
    if ( TRUE === $debug )
      return array( 'mime_type' => 'application/octet-stream', 'method' => 'last_resort' );
    return 'application/octet-stream';

  }

  /**
   * function: get_extension
   * description: returns *one* valid file extension for a given $mime_type
   */
  public function get_extension( $mime_type, $debug = FALSE ) {

    if (!empty( $this->private_file_extensions[$mime_type])) {
      if (TRUE == $debug)
        return array( 'extension' => $this->private_file_extensions[$mime_type], 'method' => 'from_array' );
      return $this->private_file_extensions[$mime_type];
    }

    if (!isset ( $this->system_exts))
      $this->system_exts = $this->system_mime_type_extensions();
    if (isset( $this->system_exts[$mime_type])) {
      if (TRUE == $debug)
        return array( 'extension' => $this->system_exts[$mime_type], 'method' => 'mime.types' );
      return $this->system_exts[$mime_type];
    }

    if (TRUE == $debug)
      return array( 'extension' => 'bin', 'method' => 'last_resort' );
    return 'bin';
  }

  /**
   * function: system_mime_type_extensions
   * description: populates an internal array of mimetype/extension associations
   * from the system mime.types file, or a local mime.types if one is found (see 
   * __constuctor). 
   * return: array of mimetype => extension
   */
  private function system_mime_type_extensions() {
    $out = array();
    $file = fopen($this->etc_mime_types, 'r');
    while (($line = fgets($file)) !== FALSE) {
      $line = trim(preg_replace('/#.*/', '', $line));
      if (!$line)
        continue;
      $parts = preg_split('/\s+/', $line);
      if (count($parts) == 1)
        continue;
        // A single part means a mimetype without extensions, which we ignore.
      $type = array_shift($parts);
      if (!isset($out[$type]))
        $out[$type] = array_shift($parts);
        // We take the first ext from the line if many are present.
    }
    fclose($file);
    return $out;
  }

  /**
   * function: system_mime_type_extensions
   * description: populates an internal array of mimetype/extension associations
   * from the system mime.types file, or a local mime.types if one is found (see 
   * __constuctor). 
   * return: array of extension => mimetype
   */
  private function system_extension_mime_types() {
    $out = array();
    $file = fopen($this->etc_mime_types, 'r');
    while (($line = fgets($file)) !== FALSE) {
      $line = trim(preg_replace('/#.*/', '', $line));
      if (!$line)
        continue;
      $parts = preg_split('/\s+/', $line);
      if (count($parts) == 1)
        continue;
        // A single part means a mimetype without extensions, which we ignore.
      $type = array_shift($parts);
      foreach ($parts as $part)
        $out[$part] = $type;
    }
    fclose($file);
    return $out;
  }

}