<?php
  /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *	   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  /**
   * Log events to a system log using the PHP syslog() function.
   *
   * This appenders requires a layout.
   *
   * ## Configurable parameters: ##
   * 
   * - **ident** - The ident of the syslog message.
   * - **priority** - The priority for the syslog message (used when overriding 
   *     priority).
   * - **facility** - The facility for the syslog message
   * - **overridePriority** - If set to true, the message priority will always 
   *     use the value defined in {@link $priority}, otherwise the priority will
   *     be determined by the message's log level.  
   * - **option** - The option value for the syslog message. 
   *
   * Recognised syslog options are:
   * 
   * - CONS 	 - if there is an error while sending data to the system logger, write directly to the system console
   * - NDELAY - open the connection to the logger immediately
   * - ODELAY - delay opening the connection until the first message is logged (default)
   * - PERROR - print log message also to standard error
   * - PID    - include PID with each message
   * 
   * Multiple options can be set by delimiting them with a pipe character, 
   * e.g.: "CONS|PID|PERROR".
   * 
   * Recognised syslog priorities are:
   * 
   * - EMERG
   * - ALERT
   * - CRIT
   * - ERR
   * - WARNING
   * - NOTICE
   * - INFO
   * - DEBUG
   *
   * Levels are mapped as follows:
   * 
   * - <b>FATAL</b> to LOG_ALERT
   * - <b>ERROR</b> to LOG_ERR 
   * - <b>WARN</b> to LOG_WARNING
   * - <b>INFO</b> to LOG_INFO
   * - <b>DEBUG</b> to LOG_DEBUG
   * - <b>TRACE</b> to LOG_DEBUG
   *
   * @version $Revision: 1337820 $
   * @package log4php
   * @subpackage appenders
   * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
   * @link http://logging.apache.org/log4php/docs/appenders/syslog.html Appender documentation
   */ 
  class LoggerAppenderSyslog extends LoggerAppender {
  	
  	/**
  	 * The ident string is added to each message. Typically the name of your application.
  	 * 
  	 * @var string 
  	 */
  	protected $ident = "Apache log4php";
  
  	/**
  	 * The syslog priority to use when overriding priority. This setting is 
  	 * required if {@link overridePriority} is set to true. 
  	 * 
  	 * @var string 
  	 */
  	protected $priority;
  	
  	/**
  	 * The option used when opening the syslog connection.
  	 * 
  	 * @var string
  	 */
  	protected $option = 'PID|CONS';
  	
  	/**
  	 * The facility value indicates the source of the message.
  	 *
  	 * @var string
  	 */
  	protected $facility = 'USER';
  	
  	/**
  	 * If set to true, the message priority will always use the value defined 
  	 * in {@link $priority}, otherwise the priority will be determined by the 
  	 * message's log level.
  	 *
  	 * @var string
  	 */
  	protected $overridePriority = false;
  
  	/**
  	 * Holds the int value of the {@link $priority}.
  	 * @var int
  	 */
  	private $intPriority;
  	
  	/**
  	 * Holds the int value of the {@link $facility}.
  	 * @var int
  	 */
  	private $intFacility;
  	
  	/**
  	 * Holds the int value of the {@link $option}.
  	 * @var int
  	 */
  	private $intOption;
  
  	/**
  	 * Sets the {@link $ident}.
  	 *
  	 * @param string $ident
  	 */
  	public function setIdent($ident) {
  		$this->ident = $ident; 
  	}
  	
  	/**
  	 * Sets the {@link $priority}.
  	 *
  	 * @param string $priority
  	 */
  	public function setPriority($priority) {
  		$this->priority = $priority;
  	}
  	
  	/**
  	 * Sets the {@link $facility}.
  	 *
  	 * @param string $facility
  	 */
  	public function setFacility($facility) {
  		$this->facility = $facility;
  	} 
  	
  	/**
  	 * Sets the {@link $overridePriority}.
  	 *
  	 * @param string $overridePriority
  	 */
  	public function setOverridePriority($overridePriority) {
  		$this->overridePriority = $overridePriority;
  	} 
  	
  	/**
  	* Sets the 'option' parameter.
  	*
  	* @param string $option
  	*/
  	public function setOption($option) {
  		$this->option = $option;
  	}
  	
  	/**
  	* Returns the 'ident' parameter.
  	*
  	* @return string $ident
  	*/
  	public function getIdent() {
  		return $this->ident;
  	}
  	
  	/**
  	 * Returns the 'priority' parameter.
  	 *
  	 * @return string
  	 */
  	public function getPriority() {
  		return $this->priority;
  	}
  	
  	/**
  	 * Returns the 'facility' parameter.
  	 *
  	 * @return string
  	 */
  	public function getFacility() {
  		return $this->facility;
  	}
  	
  	/**
  	 * Returns the 'overridePriority' parameter.
  	 *
  	 * @return string
  	 */
  	public function getOverridePriority() {
  		return $this->overridePriority;
  	}
  	
  	/**
  	 * Returns the 'option' parameter.
  	 *
  	 * @return string
  	 */
  	public function getOption() {
  		return $this->option;
  	}
  	
  	
  	public function activateOptions() {
  		$this->intPriority = $this->parsePriority();
  		$this->intOption   = $this->parseOption();
  		$this->intFacility = $this->parseFacility();
  		
  		$this->closed = false;
  	}
  	
  	public function close() {
  		if($this->closed != true) {
  			closelog();
  			$this->closed = true;
  		}
  	}
  
  	/** 
  	 * Appends the event to syslog.
  	 * 
  	 * Log is opened and closed each time because if it is not closed, it
  	 * can cause the Apache httpd server to log to whatever ident/facility 
  	 * was used in openlog().
  	 *
  	 * @see http://www.php.net/manual/en/function.syslog.php#97843
  	 */
  	public function append(LoggerLoggingEvent $event) {
  		$priority = $this->getSyslogPriority($event->getLevel());
  		$message = $this->layout->format($event);
  	
  		openlog($this->ident, $this->intOption, $this->intFacility);
  		syslog($priority, $message);
  		closelog();
  	}
  	
  	/** Determines which syslog priority to use based on the given level. */
  	private function getSyslogPriority(LoggerLevel $level) {
  		if($this->overridePriority) {
  			return $this->intPriority;
  		}
  		return $level->getSyslogEquivalent();
  	}
  	
  	/** Parses a syslog option string and returns the correspodning int value. */
  	private function parseOption() {
  		$value = 0;
  		$options = explode('|', $this->option);
  	
  		foreach($options as $option) {
  			if (!empty($option)) {
  				$constant = "LOG_" . trim($option);
  				if (defined($constant)) {
  					$value |= constant($constant);
  				} else {
  					trigger_error("log4php: Invalid syslog option provided: $option. Whole option string: {$this->option}.", E_USER_WARNING);
  				}
  			}
  		}
  		return $value;
  	}
  	
  	/** Parses the facility string and returns the corresponding int value. */
  	private function parseFacility() {
  		if (!empty($this->facility)) {   
  			$constant = "LOG_" . trim($this->facility);
  			if (defined($constant)) {
  				return constant($constant);
  			} else {
  				trigger_error("log4php: Invalid syslog facility provided: {$this->facility}.", E_USER_WARNING);
  			}
  		}
  	}
  
  	/** Parses the priority string and returns the corresponding int value. */
  	private function parsePriority() {
  		if (!empty($this->priority)) {
  			$constant = "LOG_" . trim($this->priority);
  			if (defined($constant)) {
  				return constant($constant);
  			} else {
  				trigger_error("log4php: Invalid syslog priority provided: {$this->priority}.", E_USER_WARNING);
  			}
  		}	
  	}
  }