<?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."&amp;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($file) &amp;&amp; file_exists($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 &amp;&amp; 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;
 }
}
?>

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