Limit payment module to certain group of customers?

How can I change the payment method "Check/Money Order" in v1.3.7 so that it will be displayed for
(and can only be used by) a certain group of customers defined in Group Pricing?

I would like to give "distributors" (who are defined in "group pricing"
and who get a % discount) also the possibility to use "Check/Money Order"
and pay after the receipt of the order.

The "Check/Money Order" method should not be visible for any other customers.

Currently the "Check/Money Order" module has only "Payment Zone" as 'variable'
(in the sense that is dependent on some other customer characteristics) configuration option.

It'll take a bit of custom coding:
Edit the module's update_status() function, and do a query to check the current customer's group-discount membership. If they're in the required group, allow the module to remain enabled. If they're not, disable it.

Thanks!
I will experiment with the Module's update_status() function.

I edited /includes/modules/payment/moneyorder.php and included:

//check if current customer is part of a certain (customers_group_pricing) group pricing (zen_group_pricing -> 1) category
$gpcheck = $db->Execute("select count(*) as count from " . TABLE_CUSTOMERS . " where customers_id = '".$order->customer['customers_id']."' AND customers_group_pricing = '1'; ");
if ($gpcheck->fields['count'] >0){ $check_flag = true; }else{ $check_flag = false; }
//end modification

into the class method function update_status().
I am trying to check if the current customer is part of the
Group Pricing group "1" and if not, disabling this payment method.
Unfortunately it is not working.
Did I make some error, or is this modification not possible this way?

// class methods
    function update_status() {
      global $order, $db;

      if ( ($this->enabled == true) && ((int)MODULE_PAYMENT_MONEYORDER_ZONE > 0) ) {
        $check_flag = false;
        $check = $db->Execute("select zone_id from " . TABLE_ZONES_TO_GEO_ZONES . " where geo_zone_id = '" . MODULE_PAYMENT_MONEYORDER_ZONE . "' and zone_country_id = '" . $order->billing['country']['id'] . "' order by zone_id");
        while (!$check->EOF) {
          if ($check->fields['zone_id'] < 1) {
            $check_flag = true;
            break;
          } elseif ($check->fields['zone_id'] == $order->billing['zone_id']) {
            $check_flag = true;
            break;
          }
          $check->MoveNext();
        }

        //check if current customer is part of a certain (customers_group_pricing) group pricing (zen_group_pricing -> 1) category
        $gpcheck = $db->Execute("select count(*) as count from " . TABLE_CUSTOMERS . " where customers_id = '".$order->customer['customers_id']."' AND customers_group_pricing = '1'; ");
        if ($gpcheck->fields['count'] >0){ $check_flag = true; }else{ $check_flag = false; }
        //end modification

        if ($check_flag == false) {
          $this->enabled = false;
        }
      }

By "it's not working", do you mean it's just not giving you what you expected? Or throwing an error?

I'd be inclined to suggest that you remove the ; in the query, since it's irrelevant in this sort of approach.
I'd also suggest changing $order->customer['customers_id'] to $_SESSION['customer_id']
I'd also remove the else { $check_flag = false;} part of your if statement.

Sorry, I meant that the code did not change the status of the payment module.
I did not get any errors.
With your help I changed the code to:

// class methods
    function update_status() {
      global $order, $db;

      if ( ($this->enabled == true) && ((int)MODULE_PAYMENT_MONEYORDER_ZONE > 0) ) {
        $check_flag = false;
        $check = $db->Execute("select zone_id from " . TABLE_ZONES_TO_GEO_ZONES . " where geo_zone_id = '" . MODULE_PAYMENT_MONEYORDER_ZONE . "' and zone_country_id = '" . $order->billing['country']['id'] . "' order by zone_id");
        while (!$check->EOF) {
          if ($check->fields['zone_id'] < 1) {
            $check_flag = true;
            break;
          } elseif ($check->fields['zone_id'] == $order->billing['zone_id']) {
            $check_flag = true;
            break;
          }
          $check->MoveNext();
        }

        //check if current customer is part of a certain (customers_group_pricing) group pricing (zen_group_pricing -> 1) category
        $gpcheck = $db->Execute("select count(*) as count from " . TABLE_CUSTOMERS . " where customers_id = '".$_SESSION['customer_id']."' AND customers_group_pricing = '1' ");
        if ($gpcheck->fields['count'] >0){ $check_flag = true; }
        //end modification

        if ($check_flag == false) {
          $this->enabled = false;
        }
      }
    }
```However, it still does not work properly: 
the (Check/Money Order) payment module is published 
(Payment Zone: --none--,  Set Order Status: default, Sort order of display: 0).
But the module is shown in all cases; the added code does not hide the payment module for customers who are NOT in the Group Price group (who have customers_group_pricing=1 in their record).

I analysed the code that is parsed just before my modification:
If the module is enabled and the customer is located in the zone were the payment module is assigned to, then **$check_flag = true;**
In case it is set to **$check_flag = true; **then my modification cannot alter it to false, can it?
So maybe I should add the else { $check_flag = false;}  part to my if statement?


Furthermore I have two general questions regarding module modification:- If the PHP code of some module is changed, are the effects immediate?
Or should I unpublish (remove) the module and republish (install) it before any changes will work?
- How can you debug the modules?
Using echo / print_r commands won't work: 
there will be no screen output from within the class/method.

pe7er:

Furthermore I have two general questions regarding module modification:- >

• If the PHP code of some module is changed, are the effects immediate?

Or should I unpublish (remove) the module and republish (install) it before any changes will work?

• How can you debug the modules?

Using echo / print_r commands won't work:
there will be no screen output from within the class/method.

1. With this particular change, the effects are immediate.
2. Sometimes you need to use die() statements instead of echo/print statements, due to page-refresh actions, etc. You could also log info to a file using the errorlog() function ie: in conjunction with this contrib: http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=860