In this post, I cover the PHP code for creating captcha code to be stored in a session variable. I start the session to store the captcha which is dynamically created using the PHP rand() function. I have created an image target layer and write the random code. This JPEG captcha image will be shown in the contact form. like this image.
Add Captcha into HTML Contact Form.
This 'demo.php' file shows the HTML contact form with the CAPTCHA code.
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>PHP Captcha</title>
<link href="./css/style.css" rel="stylesheet">
<script type='text/javascript'>
function refreshCaptcha(){
var img = document.images['captchaimg'];
img.src = img.src.substring(0,img.src.lastIndexOf("?"))+"?rand="+Math.random()*1000;
}
</script>
</head>
<body>
<div id="frame0">
<h1>PHP Captcha Demo</h1>
</div>
<br>
<form action="" method="post" name="form1" id="form1" >
<table width="400" border="0" align="center" cellpadding="5" cellspacing="1" class="table">
<?php if(isset($msg)){?>
<tr>
<td colspan="2" align="center" valign="top"><?php echo $msg;?></td>
</tr>
<?php } ?>
<tr>
<td align="right" valign="top"> Validation code:</td>
<td><img src="captcha.php?rand=<?php echo rand();?>" id='captchaimg'><br>
<label for='message'>Enter the code above here :</label>
<br>
<input id="captcha_code" name="captcha_code" type="text">
<br>
Can't read the image? click <a href='javascript: refreshCaptcha();'>here</a> to refresh.</td>
</tr>
<tr>
<td> </td>
<td><input name="Submit" type="submit" onclick="return validate();" value="Submit" class="button1"></td>
</tr>
</table>
</form>
</body>
</html>Compare Captcha Code
On form submit, we should verify the captcha code, by comparing it with the corresponding $_SESSION variable. If match found, then, the user is recognized as human and the user information will be processed in the PHP file. Otherwise, Captcha validation error message will be displayed to the user. The code for validating the captcha is.
session_start();
if(isset($_POST['Submit'])){
// code for check server side validation
if(empty($_SESSION['captcha_code'] ) || strcasecmp($_SESSION['captcha_code'], $_POST['captcha_code']) != 0){
$msg="The Validation code does not match!";// Captcha verification is incorrect.
}else{// Captcha verification is Correct. Final Code Execute here!
$msg="The Validation code has been matched.";
}
}
PHP code to Joint Function
This 'captcha.php' file Joint function.
session_start();
include("phptextClass.php");
/*create class object*/
$phptextObj = new phptextClass();
/*phptext function to genrate image with text*/
$phptextObj->phpcaptcha('#162453','#fff',120,40,10,25);
PHP code to Create CAPTCHA
This 'phptextClass.php' file create captcha cade.
class phptextClass
{
public function phptext($text,$textColor,$backgroundColor='',$fontSize,$imgWidth,$imgHeight,$dir,$fileName)
{
/* settings */
$font = './calibri.ttf';/*define font*/
$textColor=$this->hexToRGB($textColor);
$im = imagecreatetruecolor($imgWidth, $imgHeight);
$textColor = imagecolorallocate($im, $textColor['r'],$textColor['g'],$textColor['b']);
if($backgroundColor==''){/*select random color*/
$colorCode=array('#56aad8', '#61c4a8', '#d3ab92');
$backgroundColor = $this->hexToRGB($colorCode[rand(0, count($colorCode)-1)]);
$backgroundColor = imagecolorallocate($im, $backgroundColor['r'],$backgroundColor['g'],$backgroundColor['b']);
}else{/*select background color as provided*/
$backgroundColor = $this->hexToRGB($backgroundColor);
$backgroundColor = imagecolorallocate($im, $backgroundColor['r'],$backgroundColor['g'],$backgroundColor['b']);
}
imagefill($im,0,0,$backgroundColor);
list($x, $y) = $this->ImageTTFCenter($im, $text, $font, $fontSize);
imagettftext($im, $fontSize, 0, $x, $y, $textColor, $font, $text);
if(imagejpeg($im,$dir.$fileName,90)){/*save image as JPG*/
return json_encode(array('status'=>TRUE,'image'=>$dir.$fileName));
imagedestroy($im);
}
}
public function phpcaptcha($textColor,$backgroundColor,$imgWidth,$imgHeight,$noiceLines=0,$noiceDots=0,$noiceColor='#162453')
{
/* Settings */
$text=$this->random();
$font = './font/monofont.ttf';/* font */
$textColor=$this->hexToRGB($textColor);
$fontSize = $imgHeight * 0.75;
$im = imagecreatetruecolor($imgWidth, $imgHeight);
$textColor = imagecolorallocate($im, $textColor['r'],$textColor['g'],$textColor['b']);
$backgroundColor = $this->hexToRGB($backgroundColor);
$backgroundColor = imagecolorallocate($im, $backgroundColor['r'],$backgroundColor['g'],$backgroundColor['b']);
/* generating lines randomly in background of image */
if($noiceLines>0){
$noiceColor=$this->hexToRGB($noiceColor);
$noiceColor = imagecolorallocate($im, $noiceColor['r'],$noiceColor['g'],$noiceColor['b']);
for( $i=0; $i<$noiceLines; $i++ ) {
imageline($im, mt_rand(0,$imgWidth), mt_rand(0,$imgHeight),
mt_rand(0,$imgWidth), mt_rand(0,$imgHeight), $noiceColor);
}}
if($noiceDots>0){/* generating the dots randomly in background */
for( $i=0; $i<$noiceDots; $i++ ) {
imagefilledellipse($im, mt_rand(0,$imgWidth),
mt_rand(0,$imgHeight), 3, 3, $textColor);
}}
imagefill($im,0,0,$backgroundColor);
list($x, $y) = $this->ImageTTFCenter($im, $text, $font, $fontSize);
imagettftext($im, $fontSize, 0, $x, $y, $textColor, $font, $text);
imagejpeg($im,NULL,90);/* Showing image */
header('Content-Type: image/jpeg');/* defining the image type to be shown in browser widow */
imagedestroy($im);/* Destroying image instance */
if(isset($_SESSION)){
$_SESSION['captcha_code'] = $text;/* set random text in session for captcha validation*/
}
}
/*for random string*/
protected function random($characters=6,$letters = '23456789bcdfghjkmnpqrstvwxyz'){
$str='';
for ($i=0; $i<$characters; $i++) {
$str .= substr($letters, mt_rand(0, strlen($letters)-1), 1);
}
return $str;
}
/*function to convert hex value to rgb array*/
protected function hexToRGB($colour)
{
if ( $colour[0] == '#' ) {
$colour = substr( $colour, 1 );
}
if ( strlen( $colour ) == 6 ) {
list( $r, $g, $b ) = array( $colour[0] . $colour[1], $colour[2] . $colour[3], $colour[4] . $colour[5] );
} elseif ( strlen( $colour ) == 3 ) {
list( $r, $g, $b ) = array( $colour[0] . $colour[0], $colour[1] . $colour[1], $colour[2] . $colour[2] );
} else {
return false;
}
$r = hexdec( $r );
$g = hexdec( $g );
$b = hexdec( $b );
return array( 'r' => $r, 'g' => $g, 'b' => $b );
}
/*function to get center position on image*/
protected function ImageTTFCenter($image, $text, $font, $size, $angle = 8)
{
$xi = imagesx($image);
$yi = imagesy($image);
$box = imagettfbbox($size, $angle, $font, $text);
$xr = abs(max($box[2], $box[4]));
$yr = abs(max($box[5], $box[7]));
$x = intval(($xi - $xr) / 2);
$y = intval(($yi + $yr) / 2);
return array($x, $y);
}
}
PHP Captcha Download File
Click to download core php captcha all file download now...
No comments:
Post a Comment