Use Of Notifiers - How To

[samtherobot]

Ok, I'm beggining to get the picture here.

Next challenge. I've written a class to modify the description before it is displayed. I've used the NOTIFY_MAIN_TEMPLATE_VARS_EXTRA_PRODUCT_INFO notifier to run my code after the database has been queried and before it is displayed.

I can get the description by using the GET variable products_id. However then how would I modify the variable products_description?

What I'm trying to do is parse through the description text looking for keywords I have in an array (from a glossary table). I want to make any matching terms into hyperlinks.

Related to this, I'm a little sketchy on how to tell the notifier is in a class or not. I'm assuming the class declaration should be in the same file as the notifier? ie NOTIFY_MAIN_TEMPLATE_VARS_EXTRA_PRODUCT_INFO is not in a class.

thanks, I'm liking this notifier system more and more! Any idea what phase will see all notifiers contained in classes?

[wdrwc]

I am trying to write the observer class attached to events during the checkout process. I need the session class with several variables storing values for session.
But I can not properly initialize them and get them reinitialized several times during the checkout process. A a result I loose the values assigned to these variables on previous entry to the class. It looks like I do not understand how does the ONS work.

For test purposes I wrote a stupid testclass attached to the same events. But it does not work at all. I would appreciate if someone could advice what is wrong.

The file config.testclass.php in the includes/auto_loaders directory contains:

<?php
/*
 * instantiate class.testclass at 180 - when
 * everything is initialized
 * in <root>/includes/auto_loaders
 */

$autoLoadConfig[180][]= array('autoType' => 'class',
				'loadFile' => 'observers/class.testclass.php');

$autoLoadConfig[180][]= array('autoType' => 'classInstantiate',
				'className' => 'testclass',
				'objectName' => 'testClassObject',
        'checkInstantiated' => true,
        'classSession' => true );

?>

and class.testclass.php in includes/classes/observers looks like this:

<?php

class testclass extends base {
  var $initialized= false;
  var $field;
  /*constructor*/
  function testclass() {
    global $zco_notifier;

    $this->test_log($this->initialized ."\t=initialized at start constructor");
    $this->test_log($this->field ."\t=field at start constructor");
    $zco_notifier -> attach($this,
                            array('NOTIFY_HEADER_START_CHECKOUT_CONFIRMATION',
                                  'NOTIFY_HEADER_END_CHECKOUT_CONFIRMATION',
                                  /*'NOTIFY_HEADER_END_CHECKOUT_SUCCESS',*/
                                  'NOTIFY_CHECKOUT_PROCESS_AFTER_ORDER_CREATE_ADD_PRODUCTS',
                                  'NOTIFY_HEADER_START_ACCOUNT_HISTORY_INFO'));

    if( !($this->initialized) ) {
      $this->initialized= true;
      $this->field= -10;
    }
    $this->test_log($this->initialized ."\t=initialized at end constructor");
    $this->test_log($this->field ."\t=field at end constructor");
  }
  
  /* update method */
  function update(&$callingClass, $eventID, $paramsArray) {
    if($eventID == 'NOTIFY_HEADER_START_CHECKOUT_CONFIRMATION') {
      $this->test_log($this->initialized ."\t=initialized at start " .$eventID);
      $this->test_log($this->field ."\t=field at start " .$eventID);
      $this->field= 200;
      $this->test_log($this->initialized ."\t=initialized at end " .$eventID);
      $this->test_log($this->field ."\t=field at end " .$eventID);
    } else if($eventID == 'NOTIFY_HEADER_END_CHECKOUT_CONFIRMATION') {
      $this->test_log($this->initialized ."\t=initialized at start " .$eventID);
      $this->test_log($this->field ."\t=field at start " .$eventID);
      $this->field= 300;
      $this->test_log($this->initialized ."\t=initialized at end " .$eventID);
      $this->test_log($this->field ."\t=field at end " .$eventID);
    } else if($eventID == 'NOTIFY_CHECKOUT_PROCESS_AFTER_ORDER_CREATE_ADD_PRODUCTS') {
      $this->test_log($this->initialized ."\t=initialized at start " .$eventID);
      $this->test_log($this->field ."\t=field at start " .$eventID);
      $this->field= 400;
      $this->test_log($this->initialized ."\t=initialized at end " .$eventID);
      $this->test_log($this->field ."\t=field at end " .$eventID);
    } else if($eventID == 'NOTIFY_HEADER_START_ACCOUNT_HISTORY_INFO') {
      $this->test_log($this->initialized ."\t=initialized at start " .$eventID);
      $this->test_log($this->field ."\t=field at start " .$eventID);
      $this->field= 500;
      $this->test_log($this->initialized ."\t=initialized at end " .$eventID);
      $this->test_log($this->field ."\t=field at end " .$eventID);
    }
  }
  
  /* write debug */
  function test_log($message) {
    $flog= fopen("/tmp/zc_log.txt","a");
    fwrite($flog,$message ."\n");
    fclose($flog);
  }
} /* end testclass */
?>

As you can see the class only changes the value of the $this->field and writes simple trace to the file. But the written zc_log.txt file contains only the output from the constructor method. It seems the update method is never called.
What is wrong here?