<?php
/*******************************************
 * Author: Max Nowack                      *
 * Website: www.dasnov.de                  *
 * Classname: ProofLoadedFiles             *
 *******************************************
 * Description:                            *
 * The class proof which files are loaded  *
 * from the client. With this class your   *
 * can make forms or sites securer.        *
 * Example:                                *
 * The client must load all external files *
 * they liked in the script (stylesheets,  *
 * images, etc.). Otherwise the next site  *
 * will not open.                          *
 *******************************************/

session_start();	//Start the Session. If you also use sessions on your script, comment this line out.


define("SESSION_VAR_PREFIX",	"ProofLoadedFiles_");
	
class ProofLoadedFiles
{
	var $linkTo;		//link to the file that open the other files (images, stylesheets, etc.)
	var $pathTo;		//path to the other files (images, stylesheets, etc.)
	var $loadedFiles;	//array that contains the files opened by the script
	var $showedLinks;	//array that contains the files showed by the script
	var $numSitesInSession;	//number of the runtimes of the class in this session

	function __construct($linkTo,$pathTo)
	{
		//make the sessionvars local
		$this->loadedFiles = $this->getSessionVar("loadedFiles",array());
		$this->showedLinks = $this->getSessionVar("showedLinks",array());
		$this->numSitesInSession = $this->getSessionVar("numSitesInSession",0);

		//save the classparameters
		$this->linkTo = $linkTo;
		$this->pathTo = $pathTo;

		$this->numSitesInSession++;	//increase session site number
	}

	function __destruct()
	{
		//save the localvars into sessionvars
		$this->setSessionVar("loadedFiles",$this->loadedFiles);
		$this->setSessionVar("showedLinks",$this->showedLinks);
		$this->setSessionVar("numSitesInSession",$this->numSitesInSession);
	}

	function showLinkTo($file)
	{
	//this function returns the link to the file $file
		$this->showedLinks[$this->numSitesInSession][] = $file;
		if(strstr($this->linkTo,"?"))
		{
			return $this->linkTo.$file."&x=".time();			
		}
		else
		{
			return $this->linkTo.$file."?x=".time();
		}
	}

	function getMimeType($file)
	{
	//this function returns the mimetype of the file $file
		if(function_exists(finfo_open))	//tests finfo installation
		{
			$finfo = finfo_open(FILEINFO_MIME_TYPE);	// return mime type ala mimetype extension
			return finfo_file($finfo,$this->pathTo.$file);
		}
		else	//use the old function
		{
			return mime_content_type($this->pathTo.$file);
		}
	}

	function load($file)
	{
	//this function returns the content of the file $file
	//if the link to the file was never shown in this session or , the function will return false
		$this->numSitesInSession--;	//decrease session site number
		if($this->canLoadFile($file) && file_exists($this->pathTo.$file))
		{
			$this->loadedFiles[$this->numSitesInSession][] = $file; //add the file to the loadedFiles-Array
			return file_get_contents($this->pathTo.$file); // return the file content
		}
		else
		{
			return false;
		}
	}

	function proof()
	{
	//this function proof the loaded files. If all files are loaded,
	//the function will return true. Otherwise the function return false
		if($this->numSitesInSession>1) //start just in sessions > 1
		{

			$lastSession = $this->numSitesInSession - 1; //get the last session
			
			//proof showed links and loaded files > 0
			if(count($this->loadedFiles[$lastSession])>0 && count($this->showedLinks[$lastSession])>0)
			{
				//sort the arrays
				sort($this->loadedFiles[$lastSession]);
				sort($this->showedLinks[$lastSession]);

				if($this->loadedFiles[$lastSession]==$this->showedLinks[$lastSession])
				{
					return true;
				}
				else
				{
					return false;
				}
			}
			elseif(count($this->loadedFiles[$lastSession])>0 xor count($this->showedLinks[$lastSession])>0)
			{
				return false;
			}
			else
			{
				return true;
			}

		}
		else
		{
			return true;
		}
	}

	function canLoadFile($file)
	{//this function return true if the file was allready shown
		$arr_str = json_encode($this->showedLinks);
		if(strstr($arr_str,$file))
		{
			return true;
		}
		else
		{
			return false;
		}
	}

	function getSessionVar($var,$init)
	{
		if(!isset($_SESSION[SESSION_VAR_PREFIX.$var]))
		{
			$this->setSessionVar($var,$init);
		}

		return $_SESSION[SESSION_VAR_PREFIX.$var];
	}

	function setSessionVar($var,$val)
	{
		$_SESSION[SESSION_VAR_PREFIX.$var] = $val;
	}
}
?>