I set out to create some image verification code to add to my scripts to verify human users. The best way to do this in a way that i can reuse it is in a class. Here is the first working version of this class.
N.B. You Need PHP5 to make use of this class.
PHP Code: class iv
{
/****************************************************************************************
Random key generator
****************************************************************************************/
//Temp array for storing key
private $_storky = array();
//variable for storing timestamp
private $_stamp;
//variable for storing key when generated by internal keygen
private $outkey;
//variable maximum number of characters in generated key
private $char_limit = 10;
//Public function to set the number of desired characters in key
public function setCharLimit($new_limit){
$this->char_limit = $new_limit;
}
//public function to get the number of desired characters in key
public function getCharLimit(){
return $this->char_limit;
}
//public function to generate random key
public function definekey() {
$_number = array(48,57);
$_letter = array(97,122);
$_anames = array("_number","_letter");
for($i=0;$i<$this->char_limit;$i++){
//first character is a letter
if($i==0){$_setchr=1;}
else { $_setchr = rand(0,1);}
//select a number or letter
$selected_array = $$_anames[$_setchr];
//insert selected character
$this->_storky[$i] = chr(rand($selected_array[0],$selected_array[1]));
}
//store generated key
$this->setkey(implode($this->_storky));
}
//public function to create a key with only numbers. SetCharlimit doesnt apply
public function defineNumOnlyKey(){
$this->_stamp = time();
$_myrand = rand(10000,$this->_stamp);
$_ar_rand = str_split($_myrand);
$_ranend = array_rand($_ar_rand,4);
$r_start = $_ranend[0].$_ranend[1].$_ranend[2].$_ranend[3];
$r_stamp = substr(str_shuffle($this->_stamp),0,6);
$_stamod = str_shuffle($r_start).$r_stamp;
$this->setkey($_stamod * rand(10,20));
}
//public function to store key. Can be used to store externally generated key.
public function setkey($newkey){
$this->use_default_keygen = false;
$this->outkey = $newkey;
}
//public function to return stored key
public function getkey(){
return $this->outkey;
}
/****************************************************************************************
Portion having to do with image creation
*****************************************************************************************/
//image dimensions
private $img_height;
private $img_width;
//percentage by which to increase image size. Used with function magnify()
private $ratio = 0;
//the filename of the outputed image
private $img_file_name ;
//the image font color array
private $font_color = array(3);
//the image background color array
private $bg_color = array(3);
//the image line color array
private $line_color = array(3);
/*******************************
the Following boolean values are switches to force default behaviour of certain values are not set by corresponding methods. E.G. If $this->definey() is not called and $this->setkey() is not called $this->definekey() will be called by default
***************************************/
private $use_default_bg = true;
private $use_default_fc = true;
private $use_default_dim = true;
private $use_default_img_n = true;
private $use_default_keygen = true;
private $use_default_lc = true;
//private function which sets default values if public functions to set values externally are not called
private function setworkingvalues(){
if($this->use_default_img_n){$this->img_file_name = "iv_img_file.png";}
if($this->use_default_keygen){$this->definekey();}
if($this->use_default_dim){$this->setDimensions(70,25);}
if($this->use_default_bg){$this->setbgcolor(222,223,224) ;}
if($this->use_default_fc){$this->setfontcolor(233,14,91) ;}
if($this->use_default_lc){$this->setlinecolor(156,159,163);}
}
public function setDimensions($width,$height){
$this->use_default_dim = false;
$this->img_height = $height;
$this->img_width = $width;
}
public function setbgcolor($r,$g,$b){
$this->use_default_bg = false;
$this->bg_color[0] = $r;
$this->bg_color[1] = $g;
$this->bg_color[2] = $b;
}
public function setfontcolor($r,$g,$b){
$this->use_default_fc = false;
$this->font_color[0] = $r;
$this->font_color[1] = $g;
$this->font_color[2] = $b;
}
public function setlinecolor($r,$g,$b){
$this->use_default_lc = false;
$this->line_color[0] = $r;
$this->line_color[1] = $g;
$this->line_color[2] = $b;
}
public function magnify($newratio){
$this->ratio = $newratio;
}
public function getWidth(){
return $this->img_width;
}
public function getHeight(){
return $this->img_height;
}
public function initIV(){
header ("Content-type: image/png");
$this->setworkingvalues();
$im = @imagecreatetruecolor($this->img_width,$this->img_height)
or die("Error. Ensure Gd2 is available in phpInfo");
$text_color = imagecolorallocate($im, $this->font_color[0], $this->font_color[1], $this->font_color[2]);
$back_color = imagecolorallocate($im, $this->bg_color[0],$this->bg_color[1], $this->bg_color[2]);
$stroke_color = imagecolorallocate($im, $this->line_color[0], $this->line_color[1],$this->line_color[2]);
ImageFill($im,0,0,$back_color);
imageline($im,0,0,100,25,$stroke_color);
ImageString($im, 5, 15, 5,$this->getkey(), $text_color);
/************************
if no magnification ratio set
the image will be displayed at $this->img_height and $this->img_width
************************************/
if($this->ratio!=0 && is_int($this->ratio)){
$h = $this->img_height * (($this->ratio/100) + 1);
$w = $this->img_width * (($this->ratio/100) + 1);
$zoom_height = is_float($h)?round($h):$h;
$zoom_width = is_float($w)?round($w):$w;
$zoom = @imagecreatetruecolor($zoom_width,$zoom_height);
imagecopyresized($zoom, $im, 0, 0, 0, 0, $zoom_width, $zoom_height, $this->img_width, $this->img_height);
imagepng($zoom,$this->img_file_name);
imagedestroy($zoom);
imagedestroy($im);
}
else {
imagepng($im,$this->img_file_name);
imagedestroy($im);
}
}
public function getImageName(){
return $this->img_file_name;
}
public function setImageName($new_img_name){
$this->use_default_img_n = false;
$this->$img_file_name = $new_img_name;
}
}
?>
Sample implementation
Create a php file eg. index.php and add the following code PHP Code: <?php
session_start();
include('iv_class.php');
$mykey = new iv();
$mykey->setCharLimit(5);
//if the line below is uncommented the output image should grow in size
//the value 50 is a ratio meaning 50%
//$mykey->magnify(50);
$mykey->initIV();
$_SESSION['humankey'] = $mykey->getkey();
echo "<img src='".$mykey->getImageName()".'>";
echo "<form action='iv_verify.php' method=post>";
echo "<input type='text' name='human'>";
echo "<input type='submit'>";
?>
Here is a preview of this file when opened in the browser.  I know what you are thinking....all that for that???  That is what a class does. It allows different people to use it for different situations. Naturally if this were a simple image verification there wouldn't be as much code. enjoy!!
PHP verification File
place the following code into a file iv_verify.php Note well the following code is not meant to be just pasted in your production script. It is merely an example of the use of the class.PHP Code: <?php
session_start();
echo "Challenge Code: ".$_POST['human']."<br>";
echo "Your Entery: ".$_SESSION['humankey']."<br>";
if($_POST['human'] == $_SESSION['humankey']){
echo "you have been verified!!";
}
else {echo "wrong code entered!!";}
?>
To-Do List
[1] Dynamic image format outputI am certain that the default png format will not be the desired output for all persons wishing to use this class. I will be adding a few public methods. Called SetImageTypeExt(), GetImageTypeExt(), GetImageTypeMime().This addition will be useful for persons wanting to use this class for a wap application. it would be something like this. PHP Code: /**
the following directive sets the output image
to the wbmp format commonly used on mobile phone browsers.
**/
$myiv->SetImageTypeExt('wbmp');
. As it is, the iv class basically generates an image file which is then outputed via the header() directive which cannot be sent to the browser at any point. Else you will get an error. http://www.php.net/header I am doing some testing to determine the correct way to implement this. here is the idea...... PHP Code: <?php
$myiv = new iv();
//Run all iv methods to get and set desired values
$myiv->holdOutput();
?>
<html>
hello world. Please enter something in my form before you you go any further
<?php
$myiv->initIV();
$myiv->OutputForm();
$myiv->ReleaseOutput();
?>
</html>
. Here is the idea. Someone making use of this class can have the option of using a public function to output a form. so instead of the following.. PHP Code: session_start();
include('iv_class.php');
$mykey = new iv();
$mykey->setCharLimit(5);
//$mykey->magnify(50);
$mykey->initIV();
$_SESSION['humankey'] = $mykey->getkey();
echo "<img src='iv_img_file.png'>";
echo "<form action='iv_verify.php' method=post>";
echo "<input type='text' name='human'>";
echo "<input type='submit'>";
?>
you can optionally do this. PHP Code: session_start();
include('iv_class.php');
$mykey = new iv();
$mykey->setCharLimit(5);
//$mykey->magnify(50);
$mykey->initIV();
$_SESSION['humankey'] = $mykey->getkey();
$mykey->OutputForm();
?>
Further to this a second method setFormHtml() Can be added. As with all other public set methods if it is not called a default will be assumed! PHP Code: //somewher in site definitions
$key_form_html = "<form action=iv_verify.php>"; //full custom form code
?>
verification page now sets this info to the class to be outputed PHP Code: session_start();
include('iv_class.php');
$mykey = new iv();
$mykey->setCharLimit(5);
//$mykey->magnify(50);
$mykey->initIV();
$_SESSION['humankey'] = $mykey->getkey();
$mykey->SetFormHTML($key_form_html);
$mykey->OutputForm();
?>
or PHP Code: $mykey->SetFormHTML('templates/currentTemplate/verify.html');
$mykey->OutputForm();
exampe.. PHP Code: public setfontcolor($r,$g,$b){
if(validColor($r,$g,$b){
$this->use_default_fc = false;
$this->font_color[0]=$r;
$this->font_color[1]=$g;
$this->font_color[2]=$b;
}
}
i am not sure how to warn a programmer that his supplied color is not valid...except for them to see that the colour doesnt change?? [5] Random background colors An option of having random background colors for the image can be added by simply adding colours to be used in this functionality. PHP Code: $myiv = new iv();
//add one color
$myiv->AddRandBG($r,$g,$b);
//add second color
$myiv->AddRandBG($r1,$g1,$b1);
//add third color
$myiv->AddRandBG($r2,$g2,$b2);
Upon image creation the image background color will be randomly selected from those supplied. [6] Load font filescurrently the library has 4 fonts to choose from..One would optionally be able to add their own fonts PHP Code: $myiv = new iv();
$myiv->UseFontFile($pathToFont);
This is a public method that allows a custom background to be loaded in. Using this method will automatically overide the setbgcolor() method. PHP Code: $myiv = new iv();
$mybgfile = "bgfile.png";
$myiv->LoadBgFile($mybgfile);
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