Prove of concept for a Deprecation LogWriter for TYPO3.

DeprecationWriter.php

<?php
namespace TYPO3\CMS\Core\Log\Writer;

/***************************************************************
 * Copyright notice
 *
 * (c) 2013 Steffen Müller (typo3@t3node.com)
 * All rights reserved
 *
 * This script is part of the TYPO3 project. The TYPO3 project is
 * free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * The GNU General Public License can be found at
 * http://www.gnu.org/copyleft/gpl.html.
 *
 * This script is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * This copyright notice MUST APPEAR in all copies of the script!
 ***************************************************************/
/**
 * Log writer for the deprecation log.
 * It preprocesses all deprecation records and then sends them to the LogWriter destination
 *
 * @author Steffen Müller <typo3@t3node.com>
 */
class DeprecationWriter extends \TYPO3\CMS\Core\Log\Writer\AbstractWriter {

	/**
	 * Collection of LogWriters to send the deprecation messages to
	 *
	 * @var array
	 */
	protected $logWriters = array();

	/**
	 * If set, a token for each log record is generated and stored in the sys_registry.
	 * Only those log records are written, which don't have their token registered.
	 *
	 * @var bool
	 */
	protected $filterDuplicates = FALSE;


	/**
	 * Writes the log record
	 *
	 * @param \TYPO3\CMS\Core\Log\LogRecord $record Log record
	 * @return \TYPO3\CMS\Core\Log\Writer\WriterInterface $this
	 * @throws \RuntimeException
	 */
	public function writeLog(\TYPO3\CMS\Core\Log\LogRecord $record) {
		if (!$this->filterDuplicates) {
			$this->processWriteLog($record);
		} else {
			/** @var $registry \TYPO3\CMS\Core\Registry */
			$registry = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance('TYPO3\\CMS\\Core\\Registry');
			$registeredTokens = $registry->get('core','deprecationLogTokens');
			$token = substr(md5($record->getMessage()), 0, 8);

			if (!in_array($token, $registeredTokens)) {
				$this->processWriteLog($record);
				$registeredTokens[] = $token;
				$registry->set('core','deprecationLogTokens', $registeredTokens);
			}
		}

		return $this;
	}

	protected function processWriteLog($record) {
		$logWriters = $this->getLogWriters();
		foreach ($logWriters as $logWriterClassName => $logWriterOptions) {
			/** @var $logWriter \TYPO3\CMS\Core\Log\Writer\WriterInterface */
			$logWriter = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance($logWriterClassName, $logWriterOptions);
			$logWriter->writeLog($record);
		}
	}

	/**
	 * Sets logWriters
	 *
	 * @param array $logWriters
	 * @return void
	 */
	public function setLogWriters($logWriters) {
		$this->logWriters = $logWriters;
	}

	/**
	 * Returns logWriters
	 *
	 * @return array
	 */
	public function getLogWriters() {
		return $this->logWriters;
	}

	/**
	 * Sets filterDuplicates
	 *
	 * @param boolean $filterDuplicates
	 *
	 * @return void
	 */
	public function setFilterDuplicates($filterDuplicates) {
		$this->filterDuplicates = $filterDuplicates;
	}

	/**
	 * Returns filterDuplicates
	 *
	 * @return boolean
	 */
	public function getFilterDuplicates() {
		return $this->filterDuplicates;
	}
}


?>