Code-Bin #56 - parseModRewrite()

parseModRewrite()
Posted by: TRUSTAbyss | March 16, 2009 @ 3:05pm

Revision 31 - Original post on November 7, 2007 @ 7:55pm

PHP Code

<pre>
<?php
/**
 * parseModRewrite() Function
 * Created by: Joshua H. (TRUSTAbyss)
 *
 * Usage: parseModRewrite("HTACCESS FILE") will output a multi-dimensional array
 * that can be used to convert to Abyss's URL Rewriting.
 */

function parseModRewrite($file)
{
	// Check to see if the file exists before proceeding.
	if (file_exists($file))
	{
		// Initialize the arrays and the $base variable (used for other rules).
		$array = array();
		$rewrite = array();
		$base = '';
		
		// Open the htaccess file to be parsed.
		$file_array = file($file);

foreach ($file_array as $lineNum => $line)
		{
			// Remove whitespace from the beginning and end of $line.
			$line = trim($line);
			
			// Replace whitespace inside RewriteCond/RewriteRule with \s character.
			if (preg_match("/\\\\\s/", $line))
			{
				$line = preg_replace("/\\\\\s/", "\\s", $line);
			}

// Read the current line and replace multiple whitespaces with a single space.
			$line = preg_replace("/\s+/", " ", $line);
   
			// Check for a RewriteBase.
			if (preg_match("/^RewriteBase\s(\/[^\s]*)$/i", $line, $matches))
			{
				// Create the variable for RewriteBase ($matches[1]) and store the permanent.
				$array['base'] = $matches[1];
				$base = $matches[1];
			}
   
			// Check for a RewriteCond.
			if (preg_match("/^RewriteCond\s([^\s]+)\s([^\s]+)(\s\[([^\s]+)\])?$/i", $line, $matches))
			{
				// Create the variables for Variable ($matches[1]), Expression ($matches[2]), and Flag ($matches[4]).
				$array['cond']['var'][] = $matches[1];
				$array['cond']['exp'][] = $matches[2];
				$array['cond']['fla'][] = isset($matches[4]) ? $matches[4] : 0;
				
				// Gather info about the current line (not required).
				$array['cond']['info'][] = 'Line '.($lineNum + 1).': '.$matches[0];
			}
   
			// Check for a RewriteRule.
			if (preg_match("/^RewriteRule\s([^\s]+)\s([^\s]+)(\s\[([^\s]+)\])?$/i", $line, $matches))
			{
				// Ignore the Apache specific RewriteRule that fixes the Internal Dummy Connections.
				if ($matches[2] == '-')
				{
					// Delete the conditions that belong to this RewriteRule.
					if (isset($array['cond']))
					{
						unset($array['cond']);
					}
					
					// Continue to the next RewriteRule.
					continue;
				}
				
				// Create the variables for Regexp ($matches[1]), Replacement ($matches[2]), and Flag ($matches[4]).
				$array['rule']['reg'] = $matches[1];
				$array['rule']['rep'] = $matches[2];
				$array['rule']['fla'] = isset($matches[4]) ? $matches[4] : 0;
				
				// Gather info about the current line (not required).
				$array['rule']['info'] = 'Line '.($lineNum + 1).': '.$matches[0];
			   
				// If needed, create a RewriteBase path based on where the htaccess file is located.
				if (!isset($array['base']) && empty($base))
				{
					// Create the variable for RewriteBase and store the permanent.
					$array['base'] = @str_replace('\\', '/', dirname(substr(realpath($file), strlen($_SERVER['DOCUMENT_ROOT']))));
					$base = $array['base'];
				}
				
				// Sort the rewrites in alphabetical order (base, cond, rule)
				ksort($array);
	   
				// Since we came to a RewriteRule, we can add the rewrite.
				$rewrite[] = $array;
				
				// We need to delete what was already in the array to add another rewrite.
				$array = array();
				
				// Loop through all the rewrites and change the RewriteBase if needed.
				foreach ($rewrite as $group)
				{
					if (!empty($group['base']))
					{
						$array['base'] = $base;
					}
				}
			}
		}
   
		// Return the array or FALSE if it could not be parsed.
		return (!empty($rewrite)) ? $rewrite : FALSE;
	}
	else // The file does not exist.
	{
		return FALSE; // The function must return FALSE.
	}
}

// Here's an example on using this function.
if ($parsed = parseModRewrite("drive:/path/to/.htaccess"))
{
    print_r($parsed);
}
?>
</pre>

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Author Comments

The parseModRewrite() function can be used to parse an htaccess file that contains Mod Rewrite directives, which can then be used to create a translator (e.g. AWS:MRT) for Abyss Web Server's URL Rewriting engine. This function is only recommended for advanced programmers that know how to work with multi-dimensional arrays.

Updated: March 16, 2009
-------------------------------------------------------------
The above code has been updated to ignore Rewrites that contain a "-" in the replacement URL of a RewriteRule. Abyss doesn't use the same URL Rewriting engine as Apache, so it has no need to use these types of Rewrites. The RewriteRule regular expression has also been modified so that "[" or "]" can be used in the replacement URL of a RewriteRule. Last but not least, RewriteCond's or RewriteRule's that contain whitespace are now escaped with the whitespace character \s. This keeps the translating going, even if it runs into a regular expression like "^Internet\ Explorer."

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