git.dj3c1t.com Git - mtweb/blob - mw/libs/ptitcaptcha.php

   1 <?php
   2
   3 /**
   4  * Ptitcaptcha : simple php captcha system
   5  *
   6  * @author Jean-Pierre Morfin
   7  * @license Creative Commons By
   8  * @license http://creativecommons.org/licenses/by/2.0/fr/
   9  */
  10
  11 /* Change it to have a specific encoding ! */
  12 define("PTITCAPTCHA_ENTROPY","sourceml ptitcaptcha entropy");
  13
  14 /* Choose length (max 32) */
  15 define("PTITCAPTCHA_LENGTH",5);
  16
  17 $GLOBALS["ptitcaptcha_akey"] = md5(uniqid(rand(), true));
  18
  19 /**
  20  * Helper to generate html form tags
  21  *
  22  */
  23 class PtitCaptchaHelper
  24 {
  25         /**
  26          * Generate IMG Tag
  27          *
  28          * @param string $baseuri : relative or absolute path to folder containing this file on web
  29          * @return IMG Tag
  30          */
  31         static function generateImgTags($baseuri)
  32         {
  33                 return "<a class=\"ptitcaptcha\" href=\"#\"><img alt=\"???\" title=\"?\"".
  34                         " src=\"".$baseuri."ptitcaptcha.php?pck=".$GLOBALS['ptitcaptcha_akey']."\"".
  35                         " id=\"ptitcaptcha\"".
  36                         " onclick=\"javascript:this.src='".$baseuri."ptitcaptcha.php?pck=".
  37                         $GLOBALS['ptitcaptcha_akey'].
  38                         "&amp;z='+Math.random();return false;\" /></a>";
  39         }
  40
  41         /**
  42          * Generate hidden tag (must be in a form)
  43          *
  44          * @return input hidden tag
  45          */
  46         static function generateHiddenTags()
  47         {
  48                 return "<input type=\"hidden\" name=\"ptitcaptcha_key\" value=\"".$GLOBALS['ptitcaptcha_akey']."\"/>";
  49         }
  50
  51         /**
  52          * Generate input tag (must be in a form)
  53          *
  54          * @return input tag
  55          */
  56         static function generateInputTags()
  57         {
  58                 return "<input type=\"text\" name=\"ptitcaptcha_entry\" id=\"ptitcaptcha_entry\" value=\"\"/>";
  59         }
  60
  61         /**
  62          * Check if user input is correct
  63          *
  64          * @return boolean (true=correct, false=incorrect)
  65          */
  66         static function checkCaptcha()
  67         {
  68                 if(     isset($_POST['ptitcaptcha_entry']) &&
  69                         $_POST['ptitcaptcha_entry'] == PtitCaptchaHelper::_getDisplayText($_POST['ptitcaptcha_key']))
  70                 {
  71                         return true;
  72                 }
  73                 return false;
  74         }
  75
  76         /**
  77          * Internal function
  78          *
  79          * @param string $pck
  80          * @return string
  81          */
  82         static function _getDisplayText($pck)   // internal function
  83         {
  84                 $src=md5(PTITCAPTCHA_ENTROPY.$pck);
  85                 $txt="";
  86                 for($i=0;$i<PTITCAPTCHA_LENGTH;$i++)
  87                         $txt.=substr($src,$i*32/PTITCAPTCHA_LENGTH,1);
  88                 return $txt;
  89         }
  90 }
  91
  92
  93 // If script called directly : generate image
  94 if(basename($_SERVER["SCRIPT_NAME"])=="ptitcaptcha.php" && isset($_GET["pck"]))
  95 {
  96         $width = PTITCAPTCHA_LENGTH*10+10;
  97         $height = 30;
  98
  99         $image = imagecreatetruecolor($width, $height);
 100         $bgCol = imagecolorallocate($image, rand(128,255), rand(128,255), rand(128,255));
 101         imagefilledrectangle($image,0,0,$width,$height,$bgCol);
 102
 103         $txt = PtitCaptchaHelper::_getDisplayText($_GET["pck"]);
 104
 105         for($c=0;$c<PTITCAPTCHA_LENGTH*2;$c++)
 106         {
 107                 $bgCol = imagecolorallocate($image, rand(100,255), rand(100,255), rand(100,255));
 108                 $x=rand(0,$width);
 109                 $y=rand(0,$height);
 110                 $w=rand(5,$width/2);
 111                 $h=rand(5,$height/2);
 112                 imagefilledrectangle($image,$x,$y,$x+$w,$y+$h,$bgCol);
 113                 imagecolordeallocate($image,$bgCol);
 114         }
 115         for($c=0;$c<PTITCAPTCHA_LENGTH;$c++)
 116         {
 117                 $txtCol = imagecolorallocate($image, rand(0,128) , rand(0,128), rand(0,128));
 118                 imagestring($image,5,5+10*$c,rand(0,10),substr($txt,$c,1),$txtCol);
 119                 imagecolordeallocate($image,$txtCol);
 120         }
 121
 122         header("Content-type: image/png");
 123         imagepng($image);
 124         imagedestroy($image);
 125 }
 126
 127 ?>