DrF Reverse Routing

DrF Reverse Routing is an extension of the URL Helper that overrides the site_url function to provide a reverse lookup. If a custom route can be found that matches the given "standard CodeIgniter URI", a custom route URI will be created and returned. Otherwise, a standard site_url will be returned.

[url=http://codeigniter.com/forums/viewthread/80283/]Discuss this in the Forum[/url]

[h2]Overview[/h2]

• Translates a "standard CodeIgniter URI" into a custom route if possible. Standard, in this case, means [em]controller/function/param1/param2/.../paramN[/em]
• Fails gracefully, providing a standard site_url if no route can be found/translated
• Works automatically with all of URL Helper's functions
• Concept inspired by CakePHP's reverse routing

[h2]Usage[/h2]

• place MY_url_helper.php in your system/application/helpers folder
• include the URL helper in your controller [code]$this->load->helper( 'url' );[/code]
• use URL Helper's functions as you normally would

[h2]Example[/h2]

• setup a Test Controller [code] <?php class Test extends Controller{

  function Test() { parent::Controller(); }

  function testFunc( $param1 ){ echo 'You passed in: ' . $param1; }

  function redirect() { $this->load->helper( 'url' ); redirect( 'test/testFunc/bar' ); }

} ?> [/code]

• create a route for the test function [code] ... $route['foo/(:any)'] = 'test/testFunc/$1'; ... [/code]
• Go to [b]http://www.example.com/index.php/test/redirect[/b]. Replace example.com with your server name
• You should be redirected to [b]http://www.example.com/index.php/foo/bar[/b]

[h2]Download[/h2] File:DrF_Reverse_Routing.zip

[h2]Code[/h2] system/application/helpers/MY_url_helper.php [code] <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**

• DrF Reverse Routing
• @author DrFloob
• @link http://drfloob.com/ */

// ------------------------------------------------------------------------

/**

• (Reverse) Site_URL

• Returns a custom routed URL if one exists. Returns a normal site_url otherwise.

• It works by translating the passed-in URI into a custom route URI, if possible.

• This function does not handle ANY regex used without capture-groups and back-references.

• Visit http://drfloob.com/codeIgniter/reverse_redirect to learn why

• @access public

• @param $uri The standard CI URL, e.g. controller/function/param1

• @param $method

• @param $http_response_code */

  function site_url($uri = '') { $Router =& load_class('Router');

   // $uri is expected to be a string, in the form of controller/function/param1
   // trim leading and trailing slashes, just in case
   $uri = trim($uri,'/');
   
   $routes = $Router->routes;
   $reverseRoutes = array_flip( $routes );
   
   unset( $routes['default_controller'], $routes['scaffolding_trigger'] );
   
   // Loop through all routes to check for back-references, then see if the 
   // user-supplied URI matches one 
   foreach ($routes as $key => $val)
   {
       // bailing if route contains ungrouped regex, otherwise this fails badly
       if( preg_match( '/[^\(][.+?{\:]/', $key ) )
           continue;
           
       // Do we have a back-reference?
       if (strpos($val, '$') !== FALSE AND strpos($key, '(') !== FALSE)
       {
           // Find all back-references in custom route and CI route 
           preg_match_all( '/\(.+?\)/', $key, $keyRefs );
           preg_match_all( '/\$.+?/', $val, $valRefs );
           
           // Create URI Regex, to test passed-in uri against a custom route's CI
           // (standard) route.
           // Replaces back-references in CI route with custom route's regex 
           // [ $1 replaced with (:num), for example ].
           $uriRegex = $val;
           
           foreach( $valRefs as $tempKey => $ref )
           {
               if( isset( $keyRefs[$tempKey] ) )
                   $uriRegex = str_replace( $ref, $keyRefs[$tempKey], $uriRegex );
           }
           
           // replace :any and :num with .+ and [0-9]+, respectively
           $uriRegex = str_replace(':any','.+',str_replace(':num','[0-9]+',$uriRegex));
           
           // regex creation is finished.  Test it against uri
           if (preg_match('#^'.$uriRegex.'$#', $uri))
           {
               // A match was found.  We can now build the custom URI
               
               // We need to create a custom route back-referenced regex, to plug user's
               // uri params into the new routed uri.
               // First, find all custom route strings between capture groups
               $key = str_replace(':any', '.+', str_replace(':num', '[0-9]+', $key));
  
               $routeString = preg_split( '/\(.+?\)/', $key );
               
               // build regex using original CI route's back-references
               $replacement = '';
               $rsEnd = count( $routeString ) - 1;
               
               // merge route strings with original back-references, 1-for-1
               for( $i = 0; $i < $rsEnd; $i++ ){
                   $replacement .= $routeString[$i] . $valRefs[0][$i];
               }
               $replacement .= $routeString[$rsEnd];
               
               /*
                   At this point,our variables are defined as:
                       $uriRegex:       regex to match against user-supplied URI
                       $replacement:    custom route regex, replacing capture-groups 
                                           with back-references
                           
                   All that's left to do is create the custom URI, and return the site_url
               */
               $customURI = preg_replace( '#^'.$uriRegex.'$#', $replacement, $uri );
               
               return normal_site_url( $customURI );
           }
       }
       // If there is a literal match AND no back-references are setup, and we are done
       else if($val == $uri)
           return normal_site_url( $key );
   }
   
   return normal_site_url( $uri );
  

  }

  function normal_site_url($uri = '') { $CI =& get_instance(); return $CI->config->site_url($uri); }

?> [/code]