PHP Musings

Inspired by a number of web forum “conversations,” I decided to make a little tool for stripping PHP comments from files as well as blank lines and leading white-space. This is for any of you who feel you need to save a few nano-seconds when processing PHP files, or maybe want to do a little elementary code obfuscation. The main work is done by the built-in PHP tokenizer functions.

Enjoy

<?php
/**
 * Strip comments out of PHP files
 *
 * Derived from code example at http://www.php.net/tokenizer
 *
 * Sample usage:
 *   dir_strip_comments(getcwd(), 'test');
 */

/**
 * T_ML_COMMENT does not exist in PHP 5.
 * The following three lines define it in order to
 * preserve backwards compatibility.
 *
 * The next two lines define the PHP 5 only T_DOC_COMMENT,
 * which we will mask as T_ML_COMMENT for PHP 4.
 */
if (!defined('T_ML_COMMENT')) {
   define('T_ML_COMMENT', T_COMMENT);
} else {
   define('T_DOC_COMMENT', T_ML_COMMENT);
}

/**
 * Strip PHP comments from supplied source code string
 *
 * Also strips out blank lines and leading white-space
 * @param string $source
 * @return string
 */
function strip_comments($source)
{
   $tokens = token_get_all($source);
   $result = '';
   foreach ($tokens as $token) {
      if (is_string($token)) {
         // simple 1-character token
         $result .= $token;
      } else {
         // token array
         list($id, $text) = $token;

         switch ($id) {
            case T_COMMENT:
            case T_ML_COMMENT: // we've defined this
            case T_DOC_COMMENT: // and this
               // no action on comments
               break;
            default:
               // anything else -> output "as is"
               $result .= $text;
               break;
         }
      }
   }
   return $result;
}

/**
 * Strip comments from specified file, writing to specified directory
 *
 * @param string $file
 * @param string $dir
 */
function file_strip_comments($file, $dir=null)
{
   if($dir === null)
   {
      $dir = getcwd();
   }
   $target = $dir . DIRECTORY_SEPARATOR . basename($file);
   $source = file_get_contents($file);
   if($source === false)
   {
      user_error("Unable to read file '$file'");
      return false;
   }
   $source = strip_comments(trim($source));
   $source = preg_replace('#[\r\n]\s+#', "\n", $source);
   $result = file_put_contents($target, $source);
   if($result === false)
   {
      user_error("Unable to write to file '$target'");
   }
   return $result;
}

/**
 * Strip comments from PHP files in directory
 *
 * @param string $sourceDir
 * @param string $targetDir
 * @param string $ext
 */
function dir_strip_comments($sourceDir=null, $targetDir=null, $ext='php')
{
   if($sourceDir === null)
   {
      $sourceDir = getcwd();
   }
   if($targetDir === null)
   {
      $targetDir = getcwd();
   }
   $files = glob($sourceDir . DIRECTORY_SEPARATOR . "*.$ext");
   foreach($files as $file)
   {
      $result = file_strip_comments($file, $targetDir);
      if($result)
      {
         echo "Wrote: " . $targetDir . DIRECTORY_SEPARATOR . basename($file);
      }
      else
      {
         echo "ERROR: did not write $file";
      }
      echo "<br>\n";
   }
}
?>