Dynamically set client id in checkout to be used in payment process

Question

I'd like to ask a question related to a community extension, but about how to specifically extend that extension. The extension developer's support doesn't extend this far.

It's a payment module in the checkout. In system->config->payment methods there is a field within the credit card section for client ID. I need to set it up so instead of being able to provide one client ID to the payment service as it is just now, I need the plugin to be able to handle multiple client IDs, one for each of our business partners.

So for example, a customer buys a product on the site, which belongs to one of our partners (id of 1), then the client ID sent to the payment service should be for partner 1. A product of partner 2 should send to the payment service the equivalent client id 2.

Looking at the extension code, I found the client_id section within etc/system.xml, allowing us to set the client id in admin.

Also in Model/Observer.php I can see

$clientId = Mage::getStoreConfig('payment/'.$payment->getMethod().'/client_id', $storeId);

This is overly simplistic, but could I somehow

1. Add extra sections within system.xml for each client ID I required, so these can be entered in admin (e.g. client_id1, client_id2)
2. When a product goes to checkout, use the observer to get the partner id of the product to set client id (e.g. client_id1, client_id2) to be sent to the payment service?

Or would there be a better/correct way to approach this, perhaps as a separate local extension?

Answer 1

I would advise against changing the extension files themselves for the same reason that you should not touch the core. So you should try to make your modifications in a separate local module.

• You can add additional fields to existing groups in your own system.xml.

• You can change a configuration value temporarily without saving it (see: https://magento.stackexchange.com/a/55174/243), which enables you to do something like this in your own observer:

  // decide which configuration to use:
  $clientId = Mage::getStoreConfig('payment/'.$payment->getMethod().'/client_1_id');
  // set temp. config:
  Mage::app()->getStore()->setConfig('payment/'.$payment->getMethod().'/client_id', $clientId);