I am creating a module for a 3rd party rating for Magento. I only need the rates to show in the cart checkout and there is no label creation, tracking, pickup, etc for this carrier. It will send out an XML request as a post through the HTTP/ClientFactory then parse the response to show the rates returned.
My question is, is there a requirement for this to extend AbstractCarrierOnline, like UPS, USPS, and FedEx do, or can I leave it as extending AbstractCarrier? I currently have it is working as an AbstractCarrier but when I've tried to convert it to AbstractCarrierOnline, it constructs it just fine but never hits the collectRates()
method and I don't see any errors anywhere and just says that it is not available. The one main downside I can see is that the Online includes the set and get for CachedQuotes.