Build a mailinglist

Ok, so now you have your followers registered. What if they want to unregister? We need to create a view for that as well. But we do not just want anyone to be able to enter a mail address to unregister. We want to make sure that it is someone that has received a mail from us that is doing the unregistering. So we need a unregister link that we can easily provide within each sent mail. Containing the users mail and the current mailing list sending the specific mail. And we do not want to use the users id, because that is also easy to guess or even figure out. So what want to do is use mail in combination with subscription id. We could also create a unique key for each user but that is too much work right now. In order to make this look nice in a url we just run an md5() on the values with some salt before creating the url.

// classes/Subscription.php

id.'some_salt'.$this->userId);
    }

    function getSubscribers($type, $itemId) {
        $retArr = array();
        $s = new Subscription();
        $subscribers = $s->fetchArray(' WHERE type=' . $type . ' AND item_id=' . $itemId . ' AND closed='0000-00-00'');

        foreach ($subscribers as $sub) {
            $sub->user = new User((int)$sub->userId);
            $retArr[] = $sub;
        }
        return $retArr;
    }
}

I also added a getSubscribers function, because I know that I will need that later. Now that we have our key we can generate a url that looks like this: http://mysite.com/index.php? module=subscription&view=unregister&id=1&key=64455180faa7a15cfb4d1e1dc64056a7. And here is the code that manages the unregistering of subscribers.

// views/subscription/unregister.php

getSubscriptionKey()) {
    $obj->closed = date('Y-m-d');
    $obj->update();
    echo '
You have successfully been removed from this mailing list.
';
} else {
    echo '
You could not be found in our mailing list, please contact me at me@mail.com if you are having problems.
';
}

We also need to add these files to our public pages array in index.php

    $publicPages = array(
        'post_items',
        'post_item',
        'user_login',
        'page_*',
        'subscription_register',
        'subscription_unregister'
    );

Is that it? Well no. We also want to send some mails right. Here we run in to a completely different set of issues. If I were to send all the mails directly when I create a post, then it might take a long time to save and the server might even timeout if I have a long list of subscribers. So then I might choose to only save the mails to my mail table with Mail::registerMail(). But that might also be a lot of work, at least for the mail mailing list. It would probably work fine when sending mails on post comments. But we want a separate script we can run that generates the posts in our mail table. And then we want another script running through all unsent mails and sending them. Here is another issue. It might be that this job takes a lot of resources on the server so that you want to run that at night or perhaps only send a few mails every 5 minutes. Currently I'm hosting this site at a web hotel that "only" allows 250 mails per 5 minutes. So I need to make sure that I stay below that while using this host. First of all I want to add a column to my post table, in order to keep track if I have sent it to my subscribers or not.

ALTER TABLE `post` ADD `sent` DATETIME NOT NULL;

I want to add a file that generates post mails in my mail table. In order to keep track of which post has been sent I need to add a sent column in the post table. Then I create a script that loops all my mailing list users and create a mail in the mail table.

// cron/mailinglist.php
fetchArray(' WHERE sent='0000-00-00 00:00:00' ORDER BY id LIMIT 1');

// Get a list ot subscribers
$subscribers = Subscription::getSubscribers(0, 1); // 0 = Mailinglist, 1 = item 1 because that is the one list I have

// Create a mail object
$m = new Mail();

// Loop unsent posts. Should hopefully only be one 
foreach ($posts as $post) {
    foreach ($subscribers as $sub) {
        #$u = new User((int)$sub->userId);
        #echo $u->mail.'
';

        $m->to = $sub->user->mail;
        $m->subject = $post->title . ' - JohanBroddfelt.se';
        $m->message = '' . $post->title . PHP_EOL . PHP_EOL
                    . PHP_EOL . $post->summary 
                    . PHP_EOL . PHP_EOL . 'Read the entire post at: http://www.johanbroddfelt.se/' . $post->linkTitle() . '-' . $post->id 
                    . PHP_EOL . PHP_EOL . 'Unsubscribe to post newsletter by clicking the link below:' 
                    . PHP_EOL . 'http://www.johanbroddfelt.se/index.php?module=subscription&view=unregister&id=' . $sub->id . '&key=' . $sub->getSubscriptionKey();
        
        //echo $m->message . '
';
        // Right now we only want to register the mails in the database so that we can send them later
        $m->registerMail();
    }
    // Mark the post as sent so that we do not resend mails about this post again
    $post->sent = date('Y-m-d H:i:s');
    $post->update();
    echo 'Added ' . count($subscribers) . ' subscribers to mailinglist for (' . $post->id . ') ' . $post->title . PHP_EOL;
}

And last but not least the script that actually is sending my mails.

// cron/exec_mail.php
fetchArray(' WHERE sent='0000-00-00 00:00:00' ORDER BY id LIMIT 100');

// Create a mail object
$m = new Mail();

// Loop unsent mails and send them
foreach ($mails as $mail) {
    $mail->sendMail();
}

This host does not have a crontab functionality but since I have another server I will call these scripts from there with an appropriate interval. Otherwise you could rely on your users to trigger events by executing some ajax calls in the background or something like that. Or you my decide to run the script manually your self when you actually want to send larger amounts of mail out so that you have more control.

Now there is only one thing left, and that is to add the "Call To Action" on our start page by adding the following code: Newsletter sign up and then style the #cta_newsletter to your liking in the css. And hope for all your visitors to register.

The last thing we want to do in order to complete this post is to add our cron jobs to the cron file. Here is how I do that in my case.

// crontab on my server
# johanbroddfelt.se jobs
*/5 * * * * nice -n 13 wget http://johanbroddfelt.se/cron/exec_mail.php > jb_exec_mail.log >/dev/null 2>&1; rm exec_mail.php* >/dev/null 2>&1
42 * * * * nice -n 13 wget http://johanbroddfelt.se/cron/mailinglist.php > jb_mailinglist.log >/dev/null 2>&1; rm mailinglist.php* >/dev/null 2>&1

If I have the cronjob on the same server as the site is hosted I prefer to run the script via the PHP command instead. Because then I'm not a victim to server timeout, DNS issues and network problems that can arise when routing through the Internet. >/dev/null 2>&1 looks a bit strange, but that actually prevents the cron from sending a mail to the server admin mail account every time the cronjob is executed.

2015-11-25 23:02:11 - framework, php, mailinglist, software