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Difference between revisions of "Creating a System Plugin to augment JRouter"

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{{incomplete}}{{review}}
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{{incomplete}}
The Joomla! Router can be modified with additional rules by using the attatchXRules methods.  Ideally, this can be done from a system plugin so these rules can affect be used by others.
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{{review}}
  
2 possibilities when adding rules would be that you want to augment the router functionality, or you want to replace it.
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==JRouter Hacking==
 +
The Joomla! Router can be modified with additional rules by using the attatchXRules methods.  Ideally, this can be done from a system plugin so these rules will apply globally.
 +
 
 +
Here are 2 examples of hacking JRouter using rules and a System Plugin.  One will augment the results returned by JRouter while the other will completely replace the results returned by JRouter
  
 
==Augmentation==
 
==Augmentation==
{{JVer|2.5}}  
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JRouter returns an array of variables which are then used through the API by JInput to override the actual _GET/_POST/_REQUEST variables.  If you merely want to augment the variables being returned, then this is straightforward.
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 +
{{JVer|2.5}}
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<source lang="php">
 
   class plgSystemMyRouterAugmentor extends JPlugin {
 
   class plgSystemMyRouterAugmentor extends JPlugin {
     public function onAfterInitialize()
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     public function onAfterInitialise()
 
     {
 
     {
      global $app;
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    $app = JFactory::getApplication();
    // should we  use $app = JFactory::getApplication('site'); ?
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     // get the router
 
     // get the router
 
     $router = $app->getRouter();
 
     $router = $app->getRouter();
 
     // add my own rules
 
     // add my own rules
 
     // create a callback array to call the augmentRoute method of this object
 
     // create a callback array to call the augmentRoute method of this object
     $augmentCallback = array($this, 'augmentRoute ');
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     $augmentCallback = array($this, 'augmentRoute');
 
     // attach the callback to the router
 
     // attach the callback to the router
 
     $router->attachBuildRule($myRouterCallback);
 
     $router->attachBuildRule($myRouterCallback);
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     }
 
     }
 
   }
 
   }
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</source>
  
 
==Replacement==
 
==Replacement==
{{JVer|2.5}}  
+
 
 +
JRouter returns an array of variables which are then used through the API by JInput to override the actual _GET/_POST/_REQUEST variables.  If you want to completely replace these variables, this takes a bit more work.  In this case you may need to call the parse method in a sandbox to find out what would have been the results.  You can then add/delete/modify those results.  Finally, before returning those results to JRouter for the site itself, you need to flag JRouter so it doesn't continue to process the results.
 +
 
 +
{{JVer|2.5}}
 +
<source lang="php">
 
   define('ROUTER_MODE_SKIP_SEF', 2);
 
   define('ROUTER_MODE_SKIP_SEF', 2);
 
   define('ROUTER_MODE_SKIP_RAW', -1);
 
   define('ROUTER_MODE_SKIP_RAW', -1);
 
   class plgSystemMyRouterReplacor extends JPlugin {
 
   class plgSystemMyRouterReplacor extends JPlugin {
     public function onAfterInitialize()
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     public function onAfterInitialise()
 
     {
 
     {
       global $app;
+
       $app = JFactory::getApplication();
      // should we  use $app = JFactory::getApplication('site'); ?
+
 
       // get the router
 
       // get the router
 
       $router = $app->getRouter();
 
       $router = $app->getRouter();
 
       // add my own rules
 
       // add my own rules
 
       // create a callback array to call the replaceRoute method of this object
 
       // create a callback array to call the replaceRoute method of this object
       $augmentCallback = array($this, 'replaceRoute ');
+
       $augmentCallback = array($this, 'replaceRoute');
 
       // attach the callback to the router
 
       // attach the callback to the router
 
       $router->attachBuildRule($myRouterCallback);
 
       $router->attachBuildRule($myRouterCallback);
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     }
 
     }
 
   }
 
   }
 +
</source>
  
 
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[[Category:Tutorials]][[Category:Development]]
{{license}}
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[[Category:Module Development]]
 +
[[Category:Plugin Development]][[Category:Component Development]]

Revision as of 08:13, 15 July 2013

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JRouter Hacking

The Joomla! Router can be modified with additional rules by using the attatchXRules methods. Ideally, this can be done from a system plugin so these rules will apply globally.

Here are 2 examples of hacking JRouter using rules and a System Plugin. One will augment the results returned by JRouter while the other will completely replace the results returned by JRouter

Augmentation

JRouter returns an array of variables which are then used through the API by JInput to override the actual _GET/_POST/_REQUEST variables. If you merely want to augment the variables being returned, then this is straightforward.

Joomla 2.5

  class plgSystemMyRouterAugmentor extends JPlugin {
    public function onAfterInitialise()
    {
     $app = JFactory::getApplication();
    // get the router
    $router = $app->getRouter();
    // add my own rules
    // create a callback array to call the augmentRoute method of this object
    $augmentCallback = array($this, 'augmentRoute');
    // attach the callback to the router
    $router->attachBuildRule($myRouterCallback);
    }
    /**
     * @param   JRouterSite &$router  The Joomla Site Router
     * @param   JURI  &$uri  The URI to parse
     *
     * @return  array  $vars The array of processed URI variables
    */
    public function augmentRoute ($router, $uri)
    {
      $vars = array();
      // do something to the vars
      $vars['augment'] = 'succeeded';
      // in this case, now to any Joomla! component/module it will look like ?augment=succeeded was in the url
      return $vars;
    }
  }

Replacement

JRouter returns an array of variables which are then used through the API by JInput to override the actual _GET/_POST/_REQUEST variables. If you want to completely replace these variables, this takes a bit more work. In this case you may need to call the parse method in a sandbox to find out what would have been the results. You can then add/delete/modify those results. Finally, before returning those results to JRouter for the site itself, you need to flag JRouter so it doesn't continue to process the results.

Joomla 2.5

  define('ROUTER_MODE_SKIP_SEF', 2);
  define('ROUTER_MODE_SKIP_RAW', -1);
  class plgSystemMyRouterReplacor extends JPlugin {
    public function onAfterInitialise()
    {
       $app = JFactory::getApplication();
      // get the router
      $router = $app->getRouter();
      // add my own rules
      // create a callback array to call the replaceRoute method of this object
      $augmentCallback = array($this, 'replaceRoute');
      // attach the callback to the router
      $router->attachBuildRule($myRouterCallback);
    }
    /**
     * @param   JRouterSite &$router  The Joomla Site Router
     * @param   JURI  &$uri  The URI to parse
     *
     * @return  array  $vars The array of processed URI variables
     */
    public function replaceRoute ($router, $uri)
    {
      global $app;
      // should we  use $app = JFactory::getApplication('site'); ?
      $vars = array();
      // get the true router
      $siteRouter= $app->getRouter()
     // to avoid a recursion trap, we need to make sure that only
     // the site router can call us!  We could have removed our own
     // rule the myRouter...but that would only work 
     // inside our own method!  If someone else is also
     // doing the same thing, we would have an ugly little
     // recursion where they call parse which calls us
     // and then we clone router and call parse which calls them
     // back, and forth and back and forth
     // friends don't let friends use recursion!
     if (spl_object_hash($router) != spl_object_hash($siteRouter)) {
       // oh no!  Abort, abort!
       return $vars;
      }
      // we still want to clone the router passed to us, not the true router
      // since the rules might be different
      $myRouter = clone $router;    
      //now use the power of Joomla! to parse this uri!
      $vars = $myRouter->parse($vars);
      //what is the menu id?  what is the airspeed velocity of an unladen swallow?
      $menuId = ? isset($vars['itemId'])  $vars['itemId'] : 0;
      // Please be smarter than this.  Load the menu and check the config.  Do something
      if ($menuId == 67) {
        // change the option to be a different component.
        $vars['option'] == 'com_my_custom_component';
      } 
      // $vars has both the merged values of what would have been calculated and our changes 
      // So force the siteRouter to skip more processing - no reason to process it twice!
      //$router->setMode(JROUTER_MODE_RAW);
      // if the router mode is RAW - integer 0, then _parseRawRoute will be called by JRouter
      //$router->setMode(JROUTER_MODE_SEF);
      // if the router mode is SEF - integer 1, then _parseSEFRoute will be called by JRouter
      // if we set it to something which is NOT SEF or RAW, nothing is done to it
      // false or null would be a logical choice, 
      //but since the comparison is == not === false, null and 0/RAW are the same
      // therefore we defined our own constants.
      // SEF/RAW is a binary condition of either a positive integer or not a positive integer[0]
      // so we extend that so SKIP_SEF becomes 2 so the if clause will fail, but anything else
      // counting on checking for if mode > 0 will work
      // and SKIP_RAW is -1, so anything counting on checking mode <=0 will work
      // if it is not 0 or 1, then we don't change it because something else
      // already triggered the skip.
      $mode = $router-getMode();
      if ($mode == JROUTER_MODE_RAW) {
        $router->setMode(ROUTER_MODE_SKIP_RAW);
      }
      if ($mode == JROUTER_MODE_SEF) {
        $router->setMode(ROUTER_MODE_SKIP_SEF);
      }   
      // return our custom variables
      return $vars;
    }
  }