Plugin Development - using template params in a function

Question

I'm querying an external timetable database, and I need to get the start and end points of the journey to use in a hidden field.

My template code looks like this:

{exp:get_piers:departure_pier cruise_id="{cruise_id}"}

and

{exp:get_piers:arrival_pier cruise_id="{cruise_id}"}

{cruise_id} is simply a numeric value that is set in the EE channel, but relates to the external database.

So I've created a plugin that looks like this:

class Get_piers {

    public $return_data;
    public $cruise_id;

    /**
     * Constructor
     */
    public function __construct()
    {
    $this->EE =& get_instance();
    //get cruise id from template tag
    $this->cruise_id = $this->EE->TMPL->fetch_param('cruise_id');
    //connect to external db
    $this->bookings_db = $this->EE->load->database('timetable', TRUE);
    }

// ----------------------------------------------------------------

/**
 * Departure Point
 */
function departure_pier() {
    $piers = $this->bookings_db->select('depPier')
            ->from('tbl_cruises')
            ->where('cruiseID', $this->cruise_id)
            ->get();
    return $piers->row('depPier');
    }

function arrival_pier() {   
    $piers = $this->bookings_db->select('arrPier')
            ->from('tbl_cruises')
            ->where('cruiseID', $this->cruise_id)
            ->get();
    return $piers->row('arrPier');
}

The problem is that the value for $this->cruise_id is showing in the query as '0', but if I try to return just the value for $this->cruise_id (outside the sql), I get the correct number passed through from the template.

What am I missing? I'm guessing its something to do with visibility inside/outside the function, but having tried lots of alternatives, it just ain't working for me.

Can anyone offer any pointers?

Answer 1

Numpty alert...fixed. The original code was in fact working fine, I had a stray tag in my template that had an empty parameter value - hence the null value in the SQL.

:-/