A class to manage background processes (launch, kill, get status) in PHP.

Process.class.php

<?php

class Process
{
  protected
    $command    = '',
    $outputFile = '',
    $pidFile    = ''
  ;

  public function __construct($command, $outputFile, $pidFile)
  {
    $this->setCommand($command);
    $this->setOutputFile($outputFile);
    $this->setPidFile($pidFile);
  }
  
 /**
  * Get the command
  *
  * @return string The command
  */
  public function getCommand()
  {
    return $this->command;
  }
  
 /**
  * Set the command
  *
  * @param string $command The command
  */
  public function setCommand($command)
  {
    $this->command = $command;
  }

 /**
  * Get the output file location
  *
  * @return string The output file location
  */  
  public function getOutputFile()
  {
    return $this->outputFile;
  }

 /**
  * Set the output file
  *
  * @param string $outputFile The output file location
  */  
  public function setOutputFile($outputFile)
  {
    $this->outputFile = $outputFile;
  }
  
 /**
  * Get the pid file location
  *
  * @return string The pid file location
  */ 
  public function getPidFile()
  {
    return $this->pidFile;
  }

 /**
  * Set the pid file
  *
  * @param string $pidFile The pid file location
  */    
  public function setPidFile($pidFile)
  {
    $this->pidFile = $pidFile;
  }
  
 /**
  * Execute the process
  */
  public function exec()
  {
    exec(sprintf("%s > %s 2>&1 & echo $! >> %s", $this->command, $this->outputFile, $this->pidFile));
  }
  
 /**
  * Read the PID of the process
  *
  * @return integer $pid The PID of the process
  */
  public function readPid()
  {
    $file = file($this->pidFile, FILE_SKIP_EMPTY_LINES);
    $pid = $file[count($file) - 1];
    return (int)$pid;
  }
  
 /**
  * Find out if the process is running
  *
  * @return boolean
  */
  public function isRunning()
  {
    try {
      $result = shell_exec(sprintf("ps %d", $this->readPid()));
      if (count(preg_split("/\n/", $result)) > 2) return true;
    } catch (Exception $e) {
      echo ($e->getMessage());
    }
    
    return false;
  }
  
 /**
  * Kill process if running
  */
  public function kill()
  {
    if ($this->isRunning()) {
      $result = shell_exec(sprintf("kill -9 %d", $this->readPid()));
    }
  }
}