Run a Long-Time Script with Self Modification Detection

Since PHP is convenient tool to process text contents and data from internet, sometimes we use PHP to process a large amount of data as batch script program, and running for a long time. But we may want to change the process rules from PHP script without restarting the program manually. In this case a self modification detection is very useful.

class ScriptUpdater{
  private static $scripts;
  private static $md5;
  
  //add a script file to watch the modification, filePath can be string or array
  public static function addScript($filePath){
   if(is_array($filePath)) return self::addScript(array_pop($filePath)) && self::addScript($filePath);
   return ($md5 = @md5_file($filePath)) && (self::$scripts[$filePath] = $md5);
  }
  
  //reutrn the modified file or false, (if modified excutes a function)
  public static function update($onUpdateFunc = null, $args = null){
   if($onUpdateFunc) return self::_watch() && @call_user_func_array($onUpdateFunc, $args);
   else return self::_watch();
  }
  //reutrn the modified file or false 
  private static function _watch(){
   foreach(self::$scripts as $file => $md5) 
    if(@md5_file($file) != $md5) return $file;
   return false;
  }
 }

Example Usage

//put this part at the beginning of main program
 ScriptUpdater::addScript(array(
  __FILE__, //watch the current main program
  get_included_files(), //and all required files
 ));

 //while(...){

  //Put this part when necessary, usually in the beginning of a loop 
  if($file = ScriptUpdater::update()){
   echo " -- $file modified, exiting...\n";
   exit();
  }
  
  //...
  //Process something here

 // } end of loop

Another way to deal updating

//calling the die function
 ScriptUpdater::update('die', array('PHP file has been modified, run this program again.'));

Finally, there is another problem: After terminated, how would make PHP restart automatically?
I suggest a solution by using DOS batch file, running a endless loop like this:

@echo off
 chcp 65001
 cls

 IF NOT EXIST MyProgram.php GOTO Skip
 echo Starting MyProgram at %TIME%

 for /l %%i in (1 1 10000) DO  (
  php MyProgram.php
  echo MyProgram stopped
 )
 pause

 :Skip
 echo MyProgram.php is not exists
 pause