How to create a newsletter link?

Question

I want to write a newsletter with php. but I have a question: how can I generate the code for unsubscribing. In fact, I want a unique code for each subscriber. for example, at http://net.tutsplus.com/ 'you can see something like this:' http://tutsplus.us1.list-manage.com/profile?u=0154weg635df2fdwied2541cbed&id=c5652sdfre7&e=8758563dfgde . and another question is should this code be stored in the database or not? (because I think that if it is unique to each person, there is no need to generate each time you send newsletters). any idea?

Answer 1

Create a user id hash + some secret line, put the id and hash in the link and execute it using a script that will unsubscribe the user after checking the hash.

The hash does not have to be in the database, just compute it on the fly.

Script creating a unsubscribe link:

<? $link = "unsubscribe.php?id=$user['id']&validation_hash=".md5($user['id'].$SECRET_STRING) <a href="<?=$link?>">Unsubscribe</a> 

Script link processing to unsubscribe:

 function unsubscribe() { $expected = md5( $user['id'] . $SECRET_STRING ); if( $_GET['validation_hash'] != $expected ) throw new Exception("Validation failed."); sql("UPDATE users SET wants_newsletter = FALSE WHERE id = " . escape($_GET['id']); } 

This is not the safest thing, but good enough.

Answer 2

Yes, it must be stored in the database. You should use something like wamp, lamp or xampp. These are local servers and give you the mysql database (phpmyadmin) to work with.

to connect to the database, you can use this:

 <?php define("DB_HOST", "localhost");/*host*/ define("DB_USERNAME", "username");/*username*/ define("DB_PASSWORD", "pass123");/*password*/ define("DB_NAME", "mydatabase");/*database name*/ try { $db_conn = new PDO('pgsql:host='.DB_HOST.';dbname='.DB_NAME,DB_USERNAME,DB_PASSWORD); } catch(PDOException $e) { print "Error!:".$e->getMessage()."\n"; die(); } ?> 

then you can try to create a new table in mysql as follows:

 CREATE TABLE subcribe ( subscribeId INT, emailadress VARCHAR(60), .... ); 

then you can add a subscriber to your database as follows:

If it logs in, you will set a cookie for emailadress:

 setcookie('emailadress',$hisEmailadress,time()+3600); 

then add the subscriber:

  $emailadress=$_COOKIE['emailadress']; $subscriberId = $db_conn->prepare('SELECT MAX(subscriberId) FROM subcribe'); $subscriberId ->execute(); $row = $subscriberId ->fetch(PDO::FETCH_BOTH); $subscriberId = $row[0]+1;/*unique number because it one higher then max*/ $subscriber = $db_conn->prepare("INSERT INTO subscribe(subscriberId, emailadress) VALUES('$subscriberId','$emailadress')"); $subscriber ->execute(); 

To unsubscribe, simply do the following:

 $unsubscribe = $db_conn->prepare('DELETE FROM subscribe WHERE emailadress=:emailadress'); $unsubscribe->bindParam(':emailadress',$_COOKIE['emailadress'],PDO::PARAM_STR); $unsubscribe->execute(); 

PLEASE LINK, you can do it like this and send it to email recipients:

 $length = rand(5, 10); $link= ""; for($i=0;$i< $length;$i++)/*create random link*/ { $char = rand(0, 256); if(($char>=65 && $char<=90) || ($char>=97 && $char<=122) || ($char>=48 && $char<=57)) { $char = chr($char); $link.= $link; } else $i--; } $hash = hash("ripemd160",$link); setcookie('unsubscribe',$hash,time()+300); $result = mail($emailadress, 'unsubscribe link', 'you are about to unsubscribe yourself. Click this link to unsubscribe: http://yourSite.php?link='.$link); 

And on this page, you can use the code to remove the subscriber, as described above.

PS: the link itself should not be added to the database, because you can set a cookie valid for a certain time (here it is 5 minutes). on the page of this page you can add an if-test to find out if a cookie is set, and then delete the subscriber. if(isset($_COOKIE['unsubscribe'])){...}

Hope this helps;)