A parser class for mime.types

<?php /*
**
** mime_types.inc.php
**
** (c) 2002 peppermind Network Neue Medien, www.peppermind.de
**
** Daniel Boesswetter, [email protected], Thu May 23 12:40:52 CEST 2002
** 
**
** <LEGAL BLURB>
** 1. this software is distributed free of charge (send me a mail if you like it :)
** 2. use at your own risk
** </LEGAL BLURB>
**
**
** $Log: mime_types.inc.php,v $
** Revision 1.3  2002/05/27 12:44:20  bos
** added some comments
**
** Revision 1.2  2002/05/24 09:40:50  bos
** added the default behaviour if no filename is specified: try to
** find apache's server root via the phpinfo command and
**
** Revision 1.1  2002/05/23 12:09:14  bos
** simple class for accessing apaches mime.types file
**
**
** this class provides access to the contents of the mime.types file as
** used by apache. it is based on the assumption, that a mime-type can
** have multiple associated file-extensions, but one file extension
** is only associated with one mime-type.
**
** mime.types is assumed to have one mime-type per line (with no leading
** whitespace), followed by whitespace-separated filename-extensions
** (usually without dots).
**
** todo:
** - some error-handling would be nice (e.g. file not found)
** - optimization by using global variables or class variables to
**   avoid multiple parsing of the same file in a single process (page)
** - optimize the documentation :)
**
*/

if (!defined("mime_types.inc.php")):
define("mime_types.inc.php", true);

class mime_types {

    /*
    	constructor:
	    specify a filename, if omitted will try to find it in apache's
	    server-root (by using phpinfo, see below)
    */
    function mime_types( $filename="" ) {
	if ( $filename )
	    $this->_filename = $filename;
	else
	    $this->_filename = $this->_get_default_filename();

	$this->_initialized = false;
    }

    /*
    	return the mime-type for a given file-extension
    */
    function type_by_extension( $ext ) {
    	if ( !$this->_initialized ) $this->_initialize();

	return $this->_ext2type[$ext];
    }

    /*
    	return an array of file-extensions for a given type
    */
    function extensions_by_type( $type ) {
    	if ( !$this->_initialized ) $this->_initialize();

	return $this->_type2ext[$type];
    }

    /*
    	array of known mime-types
    */
    function known_types() {
    	if ( !$this->_initialized ) $this->_initialize();

	return array_keys( $this->_type2ext );
    }

    /*
    	array of known file-extensions
    */
    function known_extensions() {
    	if ( !$this->_initialized ) $this->_initialize();

	return array_keys( $this->_ext2type );
    }

    /*
    	returns a human-readable dump of the internal state of this object
    */
    function dump() {
    	if ( !$this->_initialized ) $this->_initialize();

	ob_start();
	echo "_filename=".$this->_filename."n";
	echo "_ext2type:n";
	print_r( $this->_ext2type );
	echo "_type2ext:n";
	print_r( $this->_type2ext );
	$ret = ob_get_contents();
	ob_end_clean();
	return $ret;
    }

    /*
    	internal: read file and parse the contents
    */
    function _initialize() {

	$lines = file( $this->_filename );
	$this->_ext2type = array();
	$this->_type2ext = array();
	foreach ( $lines as $line ) {
	    if ( preg_match( "/^s*#|^s*$/", $line ) ) continue;
	    $line = chop( $line );
	    $exts = preg_split( "/s+/", $line );
	    $type = array_shift( $exts );
	    $this->_type2ext[$type] = $exts;
	    foreach ( $exts as $ext ) {
		$this->_ext2type[$ext] = $type;
	    }
	}
	$this->_initialized = true;
    }

    /*
    	try to find the servers mime.types (ugly, but it works)
    */
    function _get_default_filename() {

	/**
		capture the output of phpinfo(8) and find the table entry
		called "Server Root". mime.types usually resides
		under conf/mime.type 

		FIXME: this works only for apache!!!
	*/
	ob_start();
	phpinfo(8);
	$text = ob_get_contents();
	ob_end_clean();

	preg_match( "/Server Root(<[^>]*>)*([^<]+)/", $text, $matches );
	return $matches[2]."/conf/mime.types";
    }
}

endif;

?>