BELAJAR PHP (Captcha Security)

Buat beberapa file

1. script form.htm
2. script action.php
3. script captchasecurityimages.php
4. file font (ambil di windows)

Penjelasan:

1. script form.htm
——-
<form action=”action.php” method=”post”>
Pesan: <input type=”text” name=”message” /><br />
<img src=”/captchasecurityimages.php?width=100&height=40&character=5″ /><br />
Security Code: <input id=”security_code” name=”security_code” type=”text” /><br />
<input type=”submit” name=”submit” value=”Submit” />
</form>
——-

2. script action.php
——-
<?php
session_start();

if( isset($_POST[‘submit’])) {
if(($_SESSION[‘security_code’] == $_POST[‘security_code’]) && (!empty($_SESSION[‘security_code’])) ) {
// masukkan script anda jika validasi benar
echo ‘Terimakasih Pasan anda: “‘.$_POST[‘message’].'”‘;
} else {
// masukkan script anda jika validasi salah
echo ‘Sorry, anda memasukkan security code yang salah<br />’;
include “form.htm”;

}
} else {

include “form.htm”;

}
?>
——-

3. script captchasecurityimages.php
——-
<?php

session_start();
class CaptchaSecurityImages {
var $font = ‘monofont.ttf’;
function generateCode($characters) {
/* list all possible characters, similar looking characters and vowels have been removed */
$possible = ‘23456789bcdfghjkmnpqrstvwxyz’;
$code = ”;
$i = 0;
while ($i < $characters) {
$code .= substr($possible, mt_rand(0, strlen($possible)-1), 1);
$i++;
}
return $code;
}
function CaptchaSecurityImages($width=’120′,$height=’40’,$characters=’6′) {
$code = $this->generateCode($characters);
/* font size will be 75% of the image height */
$font_size = $height * 0.75;
$image = @imagecreate($width, $height) or die(‘Cannot Initialize new GD image stream’);
/* set the colours */
$background_color = imagecolorallocate($image, 255, 255, 255);
$text_color = imagecolorallocate($image, 20, 40, 100);
$noise_color = imagecolorallocate($image, 100, 120, 180);
/* generate random dots in background */
for( $i=0; $i<($width*$height)/3; $i++ ) {
imagefilledellipse($image, mt_rand(0,$width), mt_rand(0,$height), 1, 1, $noise_color);
}
/* generate random lines in background */
for( $i=0; $i<($width*$height)/150; $i++ ) {
imageline($image, mt_rand(0,$width), mt_rand(0,$height), mt_rand(0,$width), mt_rand(0,$height), $noise_color);
}
/* create textbox and add text */
$textbox = imagettfbbox($font_size, 0, $this->font, $code);
$x = ($width – $textbox[4])/2;
$y = ($height – $textbox[5])/2;
imagettftext($image, $font_size, 0, $x, $y, $text_color, $this->font , $code);
/* output captcha image to browser */
imagejpeg($image);
imagedestroy($image);
$_SESSION[‘security_code’] = $code;
}
}
$width = isset($_GET[‘width’]) ? $_GET[‘width’] : ‘120’;
$height = isset($_GET[‘height’]) ? $_GET[‘height’] : ’40’;
$characters = isset($_GET[‘characters’]) ? $_GET[‘characters’] : ‘6’;
header(‘Content-Type: image/jpeg’);
$captcha = new captchasecurityimages($width,$height,$characters);

?>
——-

4. file font

Gunakan font: monofont.ttf

*keterangan:
Anda harus mengupload juga file font nya, sebagai contoh saya menggunakan font “monofont.ttf”, file font yang ukurannya paling kecil cocok buat website, semua file di atas harus di tempatkan pada directory/ folder yang sama.

Perihal adekrama
World is Easy and Simple

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