When you're designing your web application, you'll find that various actions require that an email be sent off. It's easy to hard-code the email into the script. For example, in a tech support web application, you may want to send an email when a user submits a ticket, and another email alerting them of any replies.

But what happens when you have many different emails to send, and they deliver a lot of different, complex information. Then it gets too difficult to maintain many different lines of code for different emails. It's easier to create a generic email template class, and then as many templates as you want. Here's how!

Here's the template class:

class Template{
    var $template;
    var $variables;

    function Template($template){
        $this->template = @file_get_contents($template);
        $this->resetVars();
    } 

    function resetVars(){
        $this->variables = array();
    } 

    function Add($var_name, $var_data){
        $this->variables[$var_name] = $var_data;
    } 

    function AddArray($array){
        if ( !is_array($array) ){
            return;
        }
        foreach ( $array as $name => $data ){
            $this->Add($name, $data);
        }
        return;
    }

    function Evaluate($direct_output = false){
        $template = addslashes($this->template);
        foreach ( $this->variables as $variable => $data ){
            $$variable = $data;
        }
        eval("\$template = \"$template\";");
        if ( $direct_output ) {
            echo stripslashes($template);
        } else {
            return stripslashes($template);
        }
    }
}

Here's the code where you'll choose the template file, get whatever variables (username, order, etc) from the database, and merge it with the template file to send in the email.

    // build the logic to choose which template to use
    $template_file = 'templates/confirm_order.tpl';

    $template =& new Template($template_file);

    // here you need to get the user's specific data from a database, and dump it into a resultset called $result

    $from = "admin@domain.com";
    $to = "user's email address";

    foreach ( $result as $data ){
        $template->resetVars();
        $template->AddArray($data);
        $output = $template->Evaluate();
        mail( $from, $to, $output );
    }

And here's an example template file:

Your order has been confirmed, and will ship within 24 hours.

Product	     : {$product}
Url		: {$url}
Price		: {$price}
Description	: {$description}
Category	: {$category}
Contact name: {$contact_name}
Email   	: {$email}

Regards,
Company Name