Ajax attribute edition - help on transaction error ???

Thursday 26 February 2009 8:13:45 am

Hello,

I am using ajax to allow seemless content object attribute update.

My question is : "Is my technique the right one ?" Sometime it corrupt my database table and i don't know why. I have transaction errors that led one time to a total database restoration.

The problem i face is that sometimes it works and sometime it leed to a transaction error...which is very disturbing.

Here is the code in the page targeted by my ajax function :

<?php

$http = eZHTTPTool::instance();

// Execute code only if everybody is here
if ( $http->hasVariable( 'language' ) &&
     $http->hasVariable( 'contentObjectID' ) &&
     $http->hasVariable( 'attributeIdentifier' ) &&
     $http->hasVariable( 'value' )
   )
{
	$response = '';
	//$response = 'Work in progress';

	$value_new = htmlspecialchars(urldecode($http->variable( 'value' )));
	$contentObjectID = $http->variable( 'contentObjectID' );
	$attribute_identifier = $http->variable( 'attributeIdentifier' );
	$languageCode = $http->variable( 'language' );

	// Verify that language code exists in our siteaccess
	$language = eZContentLanguage::fetchByLocale( $languageCode );

	// Fetch object to update
	$contentObject = eZContentObject::fetch($contentObjectID);

	// Check if object exists && if new value is non empty && if language exists
	if($contentObject && $language)
	//if($contentObject && $language && $value_new != '')
	{
		// Retrieve attribute - returns an array
		$contentObjectAttributes = $contentObject->fetchAttributesByIdentifier(array($attribute_identifier), $contentObject->attribute('current_version'), $languageCode);

		//print_r($contentObject);

		// We check that this attribute exists
		if($contentObjectAttributes)
		{
			// Only one attribute so we have only one loop
			foreach($contentObjectAttributes as $key => $contentObjectAttribute)
			{
				$value_old = $contentObjectAttribute->toString();
			}

			// By default we return old value
			$response = $value_old;

			//echo $value_old, " : ",  $value_new,"<br>\n";

			// Create a new version & update attribute only if value has changed
			if($value_old != $value_new)
			{
				// CreateNewVersion is transaction unsafe
				$db = eZDB::instance();

				// Start to record
				$db->begin();

				// Get last version of those attributes
				$newVersion = $contentObject->createNewVersion( false, true, $languageCode, false );

				if($newVersion)
				{
					// It seems that "store" method, in function of datatype, implement his own begin/commit
					$new_version_id = $newVersion->attribute( "version" );

					$newContentObjectAttributes = $contentObject->fetchAttributesByIdentifier(array($attribute_identifier), $new_version_id, $languageCode);
					foreach($newContentObjectAttributes as $key => $newContentObjectAttribute)
					{
						$newContentObjectAttribute->fromString($value_new);
						$newContentObjectAttribute->store();
					}

					// Publish object new version
					$operationResult = eZOperationHandler::execute( 'content', 'publish', array( 'object_id' => $contentObjectID,
														     'version' => $new_version_id ) );
					// If result is made then commit all
					if($operationResult['status'])
					{
						// If new version was created then return new value
						$response = $value_new;
					}
				}

				$db->commit();
			}
			else
			{
				//$response = 'No change';
			}
		}
		else
		{
			//$response = 'Attribute not found';
		}
	}
	else
	{
		//$response = 'No object, or language not found, or empty new value';
	}

	header( $_SERVER['SERVER_PROTOCOL'] . ' 200 ' );

	header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', time() + MAX_AGE ) . ' GMT' );
	header( 'Cache-Control: cache, max-age=' . MAX_AGE . ', post-check=' . MAX_AGE . ', pre-check=' . MAX_AGE );
	header( 'Last-Modified: ' . gmdate( 'D, d M Y H:i:s', $node->ModifiedSubNode ) . ' GMT' );
	header( 'Pragma: cache' );
	header( 'Content-Type: text/html' );
	header( 'Content-Length: '.strlen( $response) );

	echo $response;
}
else
{
	header( $_SERVER['SERVER_PROTOCOL'] . ' 404 ' );
}

eZExecution::cleanExit();

?>

EZP is Great

Wednesday 15 July 2009 1:53:13 am

Uhm interesting i am gonna check this out.

Thanx !

EZP is Great

Wednesday 15 July 2009 4:24:07 am

The problem on this topic is, like often in ezp dev, the lack of documentation of the API.

- How to create an object with php ?
- How to modify an object attribute in the current version ?
- How to modify an object attribute and create a new version ?
- How to compare object versions ?

...etc

For now the response to those questions is "digg the code in /kernel & /lib and try".

At the end it usually works but first it dramatically impact developpement time and thus ezpublish adoption and second - without directives - we are never shure of using the right technique/function/class.

EZP is Great