CraftCMS Plugin Development - Part 1: How to begin a CraftCMS plugin

Since 2 years we are using CraftCMS to build wonderful websites and web applications. During development you always come to a point where you want to extend the behavior of Craft. Why not develop a small plugin for such a use case? 

Developing a CraftCMS plugin sounds harder than it is. Read through the documentation and get a short overview of the environment.Let's assume your website want to call pages of entries via a given id. You could setup a plugin which handles this route, searches for entries and redirect to them.Our Goal: Calling entries with yourdomain.com/entries/find?id=99

Settings things up

Create a folder urlbyid in your craft/plugins folder.Add a initialization class called UrlByIdPlugin.php in the plugins root folder.

// urlbyid/UrlByIdPlugin.php

<?php namespace Craft;

class UrlByIdPlugin extends BasePlugin

{

}

Give your plugin a soul and add basic information to it:

public function getName() { return 'Url by id'; }

public function getVersion() { return '1.0.0'; }

public function getDeveloper() { return 'You Name'; }

public function getDeveloperUrl() { return 'https://www.yourdomain.com'; }

If you want to display an icon in the CP of Craft place one under /resources/icon.svg.In the UrlByIdPlugin class we can register a route (action) for the website.

public function registerSiteRoutes()

{

    return array(

        'entries/find' => array('action' => 'urlById/find'),

    );

}

Your website should now accept request to yourdomain.com/entries/find. We point to a UrlByIdController and it calls the method find. So let us set'em up.

Create a controller

All controllers are grouped in the controllers folder under the root of your plugin.

// urlbyid/controllers/UrlByIdController.php

<?php namespace Craft;

class UrlByIdController extends BaseController

{

    public function actionFind()

    {

    }    

}

Our goal was:

1. Find an entry by a given id
2. If url -> redirect to it

 // get query param

 $requestedId = craft()->request->getParam('id');

 // build criteria to find model

 $criteria = craft()->elements->getCriteria(ElementType::Entry);

 $criteria->id = $requestedId;

 $criteria->limit = 1;

 

 // fire !

 $entries = $criteria->find();

 $entry = count($entries) > 0 ? $entries[0] : null;

 

 // redirect if possible

 if($entry && $entry->url) {

   // here you can redirect to that entry

 }else{

   // here you can redirect to root page or answer with a 404 status code

 }

 

 craft()->end();

Test your implementation with yourdomain.com/entries/find?id=99

Setup Template helper to generate URL

If you call {{ entry.url }} you are getting the craft url based on the settings for section. You could also write a template helper to generate the id based url. For this you have to implement a Variable for your plugin.

// urlbyid/variables/UrlByIdVariable.php

<?php namespace Craft;

class UrlByIdVariable

{

    public function urlFor($entry)

    {

      if ($entry->uri !== null)

      {

           $url = UrlHelper::getSiteUrl('entries/find', array('id' => $entry->id), null, $entry->locale);

           return $url;

      }

    }

}

You can now use that syntax in your templates to generate the id:

{{ craft.urlById.urlFor(entry) }}

See the full source code in our github repository.