Просто для забавы, вот довольно глубокий пример. Должно быть легко понять, что там происходит и почему.
Предупреждение: код не был протестирован, поэтому возможны синтаксис и другие ошибки.
<?php
// Salt for hashing confirmation keys
$salt = 'yoursecretstring12#11;.-_.21';
$url = 'http://www.yoursite.tld/thisscript.php';
$fromEmail = 'you@yoursite.tld';
$dbHost = 'localhost';
$dbUser = 'dbuser';
$dbPass = 'dbpass';
$dbDatabase = 'dbname';
mysql_connect($dbHost, $dbUser, $dbPass);
mysql_select_db($dbDatabase);
$ip = $_SERVER["REMOTE_ADDR"];
if ( isset( $_GET['key'] ) && isset( $_GET['email'] ) ) {
// If we have 'email' and 'key' parameters, we are handling an opt-in click
$email = mysql_real_escape_string( $_GET['email'] );
// Check if key matches hash of email and salt combination and if email is really an email
if ( sha1( $email.$salt ) == $_GET['key'] && filter_var($email, FILTER_VALIDATE_EMAIL) ) {
// Check if entry already exists
$checkDupes = mysql_query( "SELECT COUNT(*) as cnt FROM emails WHERE email = '$email'"; );
$result = mysql_fetch_assoc($checkDupes);
if ($result['cnt'] < 1) {
// Fresh email, insert into db along with remote ip and timestamp
mysql_query( "INSERT INTO emails (email, ip, timestamp) VALUES ( '$email', $ip, NOW() );" );
die('Subscription confirmed!');
} else {
die('Email already exists in database');
}
} else {
die('Key mismatch or invalid email!');
}
} else if ( isset( $_POST['email'] ) && filter_var($_POST['email'], FILTER_VALIDATE_EMAIL) ) {
// Form submission, send confirmation email
$email = $_POST['email'];
$key = sha1( $email.$salt );
$link = $url . '?email=' . $email . '&key=' . $key;
$mailSubject = 'Please confirm your subscription';
$mailTo = $email;
$mailBody = 'Please confirm your subscription by clicking <a href="$link">this link</a>';
$headers = 'From: ' . $fromEmail . "\r\n";
mail( $mailTo, $mailSubject, $mailBody );
} else {
// Present form and show error if needed
if ( isset( $_POST['email'] ) ) {
echo "Ivalid email submitted!<br />";
}
echo '
<form method="post" action="'.$url.'">
Email: <input type="text" name="email" /><br />
<input type="submit" value="Submit" />
</form>
';
}