Island Linux Bits and Bytes of Technology

Recently I came into a situation where a former employee had used a gateway marshaling concept and created multiple directories with the same file names (eg. www/admin/index.php. www/admin_v2/index.php). Debugging the code became problematic due to long filenames when using __FILE__. The long file paths were polluting the debug output and making it difficult to read.

I wrote a little function to return the file path based on a root directory specification. For instance if the script filename (aka __FILE__) is '/really/long/and/hard/to/read/path/www/index.php' the function will return 'www/index.php'.

This is useful for debugging calls (I use PEAR::Log) when using techniques such as:

When making multiple log entires on a complex application (think multiple AJAX calls) this approach makes debugging PHP applications faster and easier on the sanity.

Here is the code:

/**
 * Determine File Path Chunk
 * 
 * Takes the output of __FILE__ and produces a string containing all directories
 * from the specified rootDir to the script name.
 * 
 * So a __FILE__ path of /really/long/and/hard/to/read/path/www/index.php can be
 * resolved to 'www/index.php' by calling:
 * 
 * $scriptPath = getFile(__FILE__);
 * 
 * Set the debugLevel to use Pear::Log.  Note the script assumes that there is
 * an object called $log that has already been initialized as a Pear::Log
 * object.  Setting to 1 displays a message then the function is called, setting
 * to 2 displays more detailed information.  Set to zero, false, empty, or null
 * to disable the logging.
 * 
 * @param string $file
 * @param string $rootDir default 'www'
 * @param integer $debugLevel defalut 0
 * @return string
 */
function getFile($file, $rootDir = 'www', $debugLevel = 0) {
	
	if (!empty($debugLevel)) {
		global $log;	// using Pear::Log
		$log->debug(__FUNCTION__.': using file ['.$file.']');
	}
	
	$arrDir = array();	// init array for determining the file path chunk
	$breaker = 10;	// max iterations allowed; for stopping infinite loops
	
	$scriptName = basename($file);	// init the scriptName (eg. index.php)
	$dirName = dirname($file);	// init the dirname
	
	$counter = 0; // count aray elements; keep it tidy - not really needed
	while (!isset($arrDir[$rootDir])) {
		
		$key = basename($dirName);	// grab the dirName 
		$arrDir[$key] = $counter;	// add to the tracking array 
		$dirName = dirname($dirName);	// grab the last chunk of the path
		
		if ($debugLevel == 2) {	// internal debugging
			$log->debug(__FUNCTION__.': iteration ['.$counter.'] gives key ['.$key.']');
		}
		
		$counter++;	// on to track the next array element
		
		// check for breaker, if loop goes on and on the breaker will kick in
		if ($counter == $breaker) {
			if ($debugLevel == 2) {
				$log->warning(__FUNCTION__.': reached limit of ['.$limit.']');
			}
			break;
		}
		
	}
	
	$arrDir = array_reverse($arrDir);
	$arrDir = array_flip($arrDir);
	
	$ret = implode('/', $arrDir).'/'.$scriptName;
	
	return $ret;
	
}