Add weights to command plugins

I've used Mailcomment the past for projects; it's good as what it does, but doesn't work in this use case. My goal is to post replies as external notes on a support ticket via node reference. By using nodes instead of comments, I get all the goodness of content type access control and other features that come with being a real node, in order to differentiate external notes and internal-only notes, and view the whole ticket chronologically.

We're building this to move our nonprofit IT helpdesk (http://palmettotechnologyhub.org) from osTicket to something decent, without resorting to a proprietary system. If I can come up with a way to solve this last step, it will make a good install profile or distro; given the existing distro naming conventions, we'd call it something like OpenHelpdesk.

Emails are fired by a rule when a volunteer logs a note on the ticket (an External Note content type). It looks like I can't get the needed info for Mailcomment to link to the original ticket, since they do some kind of linking via custom headers, which Rules doesn't provide access to modify when sending emails.

Are there any simple examples of command plugins documented somewhere? Perhaps something that would show grabbing a single field (fromaddress, subject, whatever), adding it to $message, and providing the key/value to the feeds mapping? If not, I'll see if I can replicate the concept from your note about the file handler, as that seems pretty straightforward.

I realize it was a bit lazy to ask for the work to be handed to me. I've created a simple command plugin, tested, and it works great! Would this be useful for the docs page? If so, I'll find a good spot for it on there.

/**
 * @file
 * MailhandlerCommandsHelpdesk class.
 */

class MailhandlerCommandsHelpdesk extends MailhandlerCommands {

  /**
   * Parse the subject for a Ticket ID.
   */
  function process(&$message, $source) {

	$message['ticket_id'] = substr($message['subject'], strpos($message['subject'], 'ticket #') + 8);
  }

  function getMappingSources() {
    $sources = array();

      $sources['ticket_id'] = array(
        'title' => t('Ticket ID'),
        'description' => t('The original helpdesk ticket ID'),
      );
    return $sources;
  }
}

I have a final question related to this thread. For my testing I dropped my two custom plugin files into the sites/all/modules/mailhandler/plugins/commands_plugin folder. That's great for now, but when a new release comes out, I don't want my command to be overwritten. Is it possible to store these files elsewhere, that still makes them available to Mailhandler but doesn't live in its folder? Or is there a Mailhandler hook I can use to provide my commands via a custom module?

EDIT: I'm asking this for the purposes of the screencast I'm making that walks a user through creating a plugin, which will be part of the page I'm adding to the documentation.

I'm getting there! I don't see where in the Mailhandler module that it determines the loading order of plugins, and mine is now loading before the standard ones (which means the message hasn't been exploded, parsed, split up, etc). I've set system.weight for my module higher than Mailhandler's, and ran a 'drush cc all' a couple times, so it should be loading afterwards. Any advice on how to set the processing order of command plugins?

Edit: well poo, I just realized you said at the beginning of the issue that plugins are possibly not orderable. I'll check the Ctools queue for info on this.

merlinofchaos said this about plugin weight:

The order plugins are loaded has nothing to do with the order plugins are processed. That's up to the module implementing the plugin type. You will need to ask there, which I guess is the mailhandler module?

http://drupal.org/node/1267338#comment-4937660

Any thoughts of a patch to add a weight property to mailhander plugins? If you think that's interesting, I'm willing to give it a shot. I'm not a PHP expert though, so it may take me a while to figure out.

Here goes nothing. My patch works, but it does give a warnings because not all plugin types have weight. I get Warning: array_multisort() [function.array-multisort]: Array sizes are inconsistent.

I've never done a Git patch before, so hopefully I did it correctly.