Send a link to a friend
Creating a script that sends a link to a friend is basically an adaptation of a standard email form and processing script. All it involves is creating a link to a form where you gather the email addresses of the sender and friend, and use the $_SERVER['HTTP_REFERER'] superglobal variable to obtain the address of the page that's being recommended. However, it's important to validate the email addresses to prevent the form from being turned into a spam relay.
The following instructions create a very basic send-to-friend link and form. However, if you understand the basics of PHP, you should be able to adapt it to your own requirements.
-
In the page you want visitors to recommend, create a link like this:
<a href="sendtofriend.php?title=<?php echo urlencode('Title of the page'); ?>">Recommend this page to a friend</a>Replace
'Title of the page'with the actual title of the page. The value is passed tourlencode()to make sure it is encoded properly before it's passed as a query string appended to the end of the URL. -
In
sendtofriend.php, create a form to gather the email addresses and other details. You want the form to be displayed only if the user lands on the page after clicking the send-to-friend link. So, wrap the form in a conditional statement that checks for$_GET['title']like this:<?php if (isset($_GET['title'])) { ?> <h1>Just Fill In a Few Details</h1> <form name="form1" method="post" action="sendlink.php"> <p> <label for="friend">Your friend's name:</label> <input type="text" name="friend" id="friend"> </p> <p> <label for="to">Your friend's email address:</label> <input type="text" name="to" id="to"> </p> <p> <label for="you">Your name:</label> <input type="text" name="you" id="you"> </p> <p> <label for="sender">Your email address:</label> <input type="text" name="sender" id="sender"> </p> <p> <label for="comments">Comments:</label> <textarea name="comments" id="comments"></textarea> </p> <p> <input type="submit" name="send" id="send" value="Send to Friend"> <input name="title" type="hidden" id="title" value="<?php echo $_GET['title']; ?>"> <input name="url" type="hidden" id="url" value="<?php if (isset($_SERVER['HTTP_REFERER'])) { echo $_SERVER['HTTP_REFERER']; }?>"> </p> </form> <?php } else { ?> <h1>Oops!</h1> <p>You seem to have landed on this page by error.</p> <?php } ?>In addition to gathering the names and email addresses, the form has a field for extra comments, plus two hidden fields. The first one,
title, stores the title of the recommended page by extracting it from$_GET['title']. The other hidden field, uses the$_SERVER['HTTP_REFERER']superglobal variable to store the URL of the recommended page. You need to check for$_SERVER['HTTP_REFERER']withisset()because some browsers block access to it. -
Next, create
sendlink.php, and add the following code above theDOCTYPE:<?php if (isset($_POST['send'])) { // Validate the email addresses and URL $to = filter_input(INPUT_POST, 'to', FILTER_VALIDATE_EMAIL); $sender = filter_input(INPUT_POST, 'sender', FILTER_VALIDATE_EMAIL); $url = filter_input(INPUT_POST, 'url', FILTER_VALIDATE_URL); // Go ahead only if the values are OK if ($to && $sender && $url) { $subject = 'Check out this web page'; // Build the message $message = 'Hi, ' . strip_tags($_POST['friend']) . ",\r\n\r\n"; $message .= strip_tags($_POST['you']) . " has recommended that you check out the following web page:\r\n\r\n"; $message .= strip_tags($_POST['title']) . "\r\n\r\n"; $message .= $url . "\r\n\r\n"; $message .= strip_tags($_POST['comments']); // Add email headers $headers = "From: webmaster@example.com\r\n"; $headers .= "Reply-to: $sender\r\n"; $headers .= 'Content-type: text/plain; charset=utf-8'; $mailSent = mail($to, $subject, $message, $headers); } else { $mailSent = false; } } ?>The entire script is wrapped in a conditional statement that executes the code only if
$_POST['send']has been set. This is the name of the submit button in the form insendtofriend.php.The script begins by validating the email addresses and URL with the
filter_input()function, and storing the results in$to,$sender, and$url. This function is available in PHP 5.2 and later. If the submitted value is OK,filter_input()returns the value. Otherwise, it returnsfalse.The next part of the script, uses
$to,$sender, and$urlas conditions in a conditional statement that controls the building and sending of the email message. If any of the submitted values fails validation, the message is not sent, and$mailSentis set tofalse.The script builds the message using the values submitted by the form, but passes them to
strip_tags()as a safety precaution. (You don't need to usestrip_tags()with$to,$sender, and$urlbecause they have already been checked byfilter_input().) -
Change the value of
$subjectif you want to use a different subject line for the email. -
Change the value of the
Fromemail header fromwebmaster@example.comto your own email address. -
Many hosting companies require the use of the fifth argument to
mail()to verify that the mail is being sent by the owner of the site. This normally consists of a string beginning with-ffollowed immediately by your email address. If your hosting company requires the fifth argument, amend the call to themail()function like this (using your actual email address):$mailSent = mail($to, $subject, $message, $headers, '-fme@example.com'); -
Add the following code to the
<body>ofsendlink.php:<?php if (isset($mailSent) && $mailSent) { ?> <h1>Thank You</h1> <p>Your recommendation has been sent to <?php echo $to; ?>.</p> <?php } elseif (isset($mailSent) && !$mailSent) { ?> <h1>Sorry!</h1> <p>There was a problem sending your recommendation.</p> <?php } else { ?> <h1>Oops!</h1> <p>You seem to have landed here by mistake.</p> <?php } ?>The conditional statements use the value of
$mailSentto display a message reporting whether the link was sent successfully. If$mailSenthasn't been set, it means that someone has landed on the page without sending a link, so a suitable error message is displayed instead.
