This tutorial shows how to create a registration page that will automatically send user an automatically generated software download link using encrypted one day valid token after user register. For simplicity, the database logging is omitted.
Step 1: Create a registration form page
Create a simple registration form page registration.htm as in the follows:
<html>
<body>
Software Application Download Registration <br>
<form id="regForm" action="submit.php" method="post">
<table>
<tbody>
<tr>
<td><label for="fname">First Name:</label></td>
<td><div class="input-container"><input name="fname" id="fname" type="text" /></div></td>
</tr>
<tr>
<td><label for="lname">Last Name:</label></td>
<td><div class="input-container"><input name="lname" id="lname" type="text" /></div></td>
</tr>
<tr>
<td><label for="email">Your Email:</label></td>
<td><div class="input-container"><input name="email" id="email" type="text" /></div></td>
</tr>
<tr>
<td><label for="company">Company:</label></td>
<td><div class="input-container"><input name="company" id="company" type="text" /></div></td>
</tr>
<tr>
<td> </td>
<td><input type="submit" class="greenButton" value="Register and Download" /><img id="loading" src="img/ajax-loader.gif" alt="working.." />
</td>
</tr>
</tbody>
</table>
</form>
</body>
</html>
Step 2: Create registration submission processing server script in PHP
Create the submit.php page which processes the registration information from the registration.htm page. the submit.php page sends the registered user an email with a link to download the software, the link is valid for the current date (using the concept of token), the submit.php also cc the email to [YOUR-EMAIL-CC-ACCOUNT] (As this is a simple demo, the validation of registration information is not included here)
<?php
require_once('encryption.inc');
$token="dfjsl@ew".date('Ymd')."oqiej".date('Y')."!#@#@1".date('m')."2331";
$converter = new Encryption;
$encoded = $converter->encode($token);
$mail_server="[YOUR-MAIL-SERVER-IP-ADDRESS]";
ini_set("SMTP",$mail_server);
$to = $_POST['email'];
$cc = '[YOUR-EMAIL-CC-ACCOUNT]';
$subject = 'XXX Application Download';
$message = '<html><body><h2>User registration information: </h2><br />';
$message .= '<table>';
$message .='<tr><td><b>First Name:</b></td><td>'.$_POST['fname'].'</td></tr>';
$message .='<tr><td><b>Last Name: </b></td><td>'.$_POST['lname'].'</td></tr>';
$message .='<tr><td><b>Email: </b></td><td>'.$_POST['email'].'</td></tr>';
$message .='<tr><td><b>Company: </b></td><td>'.$_POST['company'].'</td></tr>';
$message .='</table>';
$elink = '[YOUR-WEBSITE-DOMAIN-AND-DIRECTORY]/download.php?token='.urlencode($encoded).'&attachment=vrpmac';
$message .= 'Thank you for your interest. Below is a one-day expired download link to the software.<br/>';
$message .= '<a href="'.$elink.'">'.'Download'.'</a><br>';
$message .='</body></html>';
$headers = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type:text/html;charset=iso-8859-1" . "\r\n";
$headers .= 'From: <[YOUR-EMAIL-FROM-ACCOUNT]>' . "\r\n";
$headers .= 'Bcc: ' . $cc . "\r\n";
mail($to, $subject, $message, $headers);
echo msg(1,"registered.php?token=".urlencode($encoded).'&email='.urlencode($_POST['email']));
function msg($status,$txt)
{
return '{"status":'.$status.',"txt":"'.$txt.'"}';
}
?>
The $token variable contains a token which makes the software download page generated valid for one day, to increase the security you may want to create more sophisticated token using encryption and random numbers.
The [YOUR-MAIL-SERVER-IP-ADDRESS] refers to your mail server address. The [YOUR-EMAIL-CC-ACCOUNT] refers to a cc account when the registration email is sent to the registered user. The [YOUR-WEBSITE-DOMAIN-AND-DIRECTORY] is the root directory which contains the download.php page (which is the page that provides the software download service), The [YOUR-EMAIL-FROM-ACCOUNT] is the from field in the email sent to the registered user.
The encryption.inc includes the encryption utility which prevents the user from deciphering the token. The source codes of the encryption.inc is shown below:
<?php
class Encryption {
var $skey = '[YOUR-SECRET-KEY]';
public function safe_b64encode($string) {
$data = base64_encode($string);
$data = str_replace(array('+','/','='),array('-','_',''),$data);
return $data;
}
public function safe_b64decode($string) {
$data = str_replace(array('-','_'),array('+','/'),$string);
$mod4 = strlen($data) % 4;
if ($mod4) {
$data .= substr('====', $mod4);
}
return base64_decode($data);
}
public function encode($value){
if(!$value){return false;}
$text = $value;
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $this->skey, $text, MCRYPT_MODE_ECB, $iv);
return trim($this->safe_b64encode($crypttext));
}
public function decode($value){
if(!$value){return false;}
$crypttext = $this->safe_b64decode($value);
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $this->skey, $crypttext, MCRYPT_MODE_ECB, $iv);
return trim($decrypttext);
}
}
?>
The registered.php is a page displayed to the user after user submit the registration form. The page informs user and he has successfully registered (You can include the download link here if you like). The page checks whether the token is included in the url, if not or if the token is not valid, then the user is redirected to the registration.htm page. The source code of the registered.php is as below:
<?php
require_once('encryption.inc');
if(!isset($_GET['token']))
{
header( 'Location: registration.htm' ) ;
}
$message="dfjsl@ew".date('Ymd')."oqiej".date('Y')."!#@#@1".date('m')."2331";
$converter = new Encryption;
$encode=$_GET['token'];
$decoded = $converter->decode($encode);
if(strcmp($decoded, $message) != 0)
{
header( 'Location: registration.htm' ) ;
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>You've been registered!</title>
<link rel="stylesheet" type="text/css" href="reg.css">
</head>
<body>
<div class="registered">
<h1>The application link will be sent to your email account <?php echo $_GET['email']; ?></h1>
<br /><br /><br />
<br /><br /><br /><br />
<h2>Thank you for your registration. </h2>
</div>
</body>
</html>
Step 3: Create software download page
Below is the source code for the software download page, the download script first checks whether the token is valid or not, if not then redirect user to the registration page. Otherwise, it sends the software.
<?php
require_once('encryption.inc');
if(!isset($_GET['token']))
{
header( 'Location: registration.htm' ) ;
}
$message="dfjsl@ew".date('Ymd')."oqiej".date('Y')."!#@#@1".date('m')."2331";
$converter = new Encryption;
$encode=$_GET['token'];
//$encoded = $converter->encode($message);
$decoded = $converter->decode($encode);
if(strcmp($decoded, $message) != 0)
{
header( 'Location: registration.htm' ) ;
}
if(isset($_GET['attachment']))
{
if($_GET['attachment']=='vrpmac')
{
$file = 'uyk0293fwie0.zip';
if (file_exists($file))
{
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename=painter2.zip');
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
ob_clean();
flush();
readfile($file);
}
}
}
?>
