Question

I am creating an OpenCart extension where the admin can change his email templates using the user interface in the admin panel.

I would like the user to have the option to add variables to his custom email templates. For example he could put in:

Hello $order['customer_firstname'], your order has been processed.

At this point $order would be undefined, the user is simply telling defining the message that is to be sent. This would be stored to the database and called when the email is to be sent.

The problem is, how do I get “$order['customer_firstname']” to become a litteral string, and then be converted to a variable when necessary?

Thanks
Peter

Answer 1

You could define your own simple template engine:

function template($text, $context) {
    $tags = preg_match_all('~%([a-zA-Z0-9]+)\.([a-zA-Z0-9]+)%~', $text, $matches);

    for($i = 0; $i < count($matches[0]); $i++) {
        $subject = $matches[0][$i];
        $ctx = $matches[1][$i];
        $key = $matches[3][$i];
        $value = $context[$ctx][$key];

        $text = str_replace($subject, $value, $text);
    }

    return $text;
}

This allows you to transform a string like this:

$text = 'Hello %order.name%. You have %order.percent%% discount. Pay a total ammount of %payment.ammount% using %payment.type%.';

$templated = template($text, array(
    'order' => array(
        'name' => 'Alex',
        'percent' => 20
    ),

    'payment' => array(
        'type' => 'VISA',
        'ammount' => '$299.9'
    )
));
echo $templated;

Into this:

Hello Alex. You have 20% discount. Pay a total ammount of $299.9 using VISA.

This allows you to have any number of variables defined.