Extension development help

I’m not really sure I follow with the goal of the add-on, but…

I can now call my method, but I keep getting a blank white screen anytime I try to modify or simply output a js alert. I know this is probably simple, I am just overlooking something

I suggest turning on “debug” mode in EE. I development you should seldom see a white screen. In the least you should have some PHP error messages to help tell you why the page didn’t load properly.

Erik,

Thanks. I think I was looking at it all wrong. This wasn’t really a ‘functional’ test here. Basically, I just wanted to be able to throw an alert on the page when it opened. That was all. I figured if I could get that far, I could better understand hook usage. Once the page loads, I am fine. I am just trying to get my head better wrapped around the usage of the EE hooks. (How they work, how to use them, what to return, etc…)

I figured if I could get that far, I could better understand hook usage. Once the page loads, I am fine. I am just trying to get my head better wrapped around the usage of the EE hooks. (How they work, how to use them, what to return, etc…)

Then I’d suggest you take a look at the sessions_end hook for starters. Take a look at the docs and consider the data that is passed to the extension and what data it expects back. Then based on certain session user data perform certain actions or set other variables etc. That might help get a grasp of how EE hooks work.

Erik

I read through the docs earlier this week, but still lacked a good understanding.

So on ‘session_end’, it reads: Modify the user’s session/member data, also allows for additional session or login methods (ex: log in to other system)

That hook looks like :

$edata = $this->extensions->call('sessions_end', $this);
if ($this->extensions->end_script === TRUE) return;

Being that it returns ‘void’, I initially tried to just output the data on the screen of the session inside.

At this point there wouldn’t be any entry data per say, but the user and other session data held within, correct?

If I were to do nothing more than just want to see what was passed through the hook/method call, how would I be able to view the data, like a

var_dump($this)

or

var_dump($edata)

, and halt the page load so I can analyze the available elements? Or am I still looking at it wrong? ;/

Can you show me what the method looks like in your extension?

I get the following:

PHP Fatal error: ob_start() [ref.outcontrol]: Cannot use output buffering in output buffering display handlers in C:\websites\EE2Dev\system\codeigniter\system\core\Exceptions.php on line 166

From:

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 
class Alertmee_ext
{
 public $settings = array();
 public $name = 'AlertM:ee';
 public $version = '0.0.1';
 public $description = 'A sample extension...';
 public $settings_exist = 'y';
 public $docs_url = 'http://www.google.com';

 // --------------------------------------------------------------------
   
 /**
 * Alertmee_ext
 */
 public function __construct($settings = '')
 {
  $this->EE =& get_instance();

  $this->settings = $settings;
 }

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

 /**
 * Activate Extension
 *
 * @return void
 */
 function activate_extension()
 {
  //$this->settings = $settings;

  $data = array(
   'class'     => __CLASS__,
   'method'    => 'myMethod',
   'hook'      => 'sessions_end',
   'settings'  => serialize($this->settings),
   'priority'  => 10,
   'version'   => $this->version,
   'enabled'   => 'y'
  );

  $this->EE->db->insert('extensions', $data);
 }

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

 /**
 * Update Extension
 *
 * @return  mixed   void on update / false if none
 */
 function update_extension($current = '')
 {
  if ($current == '' OR $current == $this->version)
  {
   return FALSE;
  }

  if ($current < '0.0.1')
  {
   // Update to version 1.0
  }

  $this->EE->db->where('class', 'Alertmee_ext');
  $this->EE->db->update(
   'extensions',
   array('version' => $this->version)
  );
 }

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

 /**
 * Disable Extension
 *
 * @return void
 */
 function disable_extension()
 {
  $this->EE->db->where('class', 'Alertmee_ext');
  $this->EE->db->delete('extensions');
 }

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

 /**
 * settings
 *
  * @return void
 */
 public function settings()
 {
  $settings = array();
 
  // Creates a text input with a default value of "AlertM:ee"
  $settings['name']      = array('i', '', "AlertM:ee");
 
  // Creates a textarea with 20 rows and a default value of 'This will throw a javascript alert on page load.'
  $settings['description']    = array('t', array('rows' => '20'), 'This will throw a javascript alert on page load.');
 
  // Creates a set of radio buttons, one for "Yes" (y), one for "No" (n) and a default of "Yes"
  $settings['cool']      = array('r', array('y' => "Yes", 'n' => "No"), 'y');
 
  return $settings;
 }

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

 /**
 * Save Settings
 *
 * @return void
 */
 function save_settings()
 {
  $this->EE->db->where('class', __CLASS__);
  $this->EE->db->update('extensions', array('settings' => serialize($this->settings)));
 }

 /**
 * showAlert
 *
  * @return void
 */
 public function myMethod()
 {
  if (REQ == 'PAGE')
  {
   var_dump($data);
  }
 }
}

Brian,

You need to add the hook’s parameters in your own function. The parameters available can be found in the extension hook’s documentation code example. It’s the variables that appear after the hook name in the code sample. With our example of sessions_end you current have:

public function myMethod() {}

But you should have this:

public function myMethod($data) {}

Where “$data” is the same thing as “$this” in the docs here: http://ellislab.com/expressionengine/user-guide/development/extension_hooks/global/session/index.html#sessions-end

With every hook (and with object oriented code in general) you need to include the parameter variables if you want to work with them in your own methods.

Make sense?

Erik

Yeah. Thanks Eric.

I guess my question then would be this. Is there a way to see, or preview the data being passed in those parameters? (Similar to a console log or even a var_dump) So I can better educate myself on the data being handled through the system? I know this is a quite general question so I apologize for that, I would just like to see the data contained in the object prior to “working” with it.

By the way, your help is greatly appreciated.

Brian

Is there a way to see, or preview the data being passed in those parameters? (Similar to a console log or even a var_dump)

Yes, you’re already on the right path. You just need to make the change I suggested then your var_dump will work.

Eric,

Thanks again and thumbs up to FocusLab! Another reason I love the EE community.

Brian

Glad to help, Brian. You’re on the right track. Everyone I’ve talked to (and trained) learns about these hooks in the exact same way.

Good luck!

Erik