Plugin Form Submission Best Practice

I have done a lot of researching and haven’t found quite what I am looking for, so I am hoping that I can be pointed in the right direction.

I am developing an Events plugin that will book a ticket from the frontend. This is no different than any other Form submission, but what I am getting confused with is how to handle that from a plugin that is written via OOP with a class.

Most articles that I found say to put the $_POST handling within the template page. Ideally I would like to have this handled by a function within the plugin.

The other thing that I am not sure about is when you submit the form on the frontend, how that actually gets passed to the function on the backend. I am hoping to completely abstract the form processing from any template details.

// events.php
if ( ! class_exists( 'Events' ) ) {

    Class Events {
        function __construct() {
            add_action( 'plugins_loaded', array( &$this, 'includes' ), 1 );
        }

        function includes() {
            require_once( EVENTS_INCLUDES . 'functions.php' );
        }
    }
}

if ( class_exists( 'Events' ) ) {
    $events_load = New Events();
}


// functions.php
function process_form() {
    ...do form processing here...

    ...insert booking...
}

I’m not sure what to hook into that would catch that, or where to send the form action too. Thanks for all the help!

-Adam

Send the form action either to your homepage, or to a specific page URL. You can’t have $_POST handling within the template because you need to redirect after your process it, and redirect needs to be fired before any HTML output.

// you should choose the appropriate tag here
// template_redirect is fired just before any html output
// see - http://codex.wordpress.org/Plugin_API/Action_Reference
add_action('template_redirect', 'check_for_event_submissions');

function check_for_event_submissions(){
  if(isset($_POST['event'])) // && (get_query_var('pagename') === 'events) 
    {
       // process your data here, you'll use wp_insert_post() I assume

       wp_redirect($_POST['redirect_url']); // add a hidden input with get_permalink()
       die();
    } 

}

You could also check for a nonce to make sure the data was submitted from the right place…