Configuring CommerceRuntime extensions properly

The CommerceRuntime is the business logic for Retail POS and other channels. Here are a couple of good rules how to correctly configure it.

1. In both of the commerceRuntime.*.ext files, be specific about what handlers you want. Do not use a wildcard inclusion for the whole assembly. If you do the latter, you have no choice about what handlers are disabled, etc.  The example below should help.
2. Even though you could write code that figures out where the runtime context is online or offline, its not a good practice. Its better practice to use the config file to control that. See example below.
3. To enable different functionality for online and offline scenarios, you have multiple options:
   1. If you do not want/need offline mode at all, either disable the feature for that register OR install the installer that does not include the offline part.
   2. If you want just the built-in offline features (fewer features than online), you can have an empty CommerceRuntime.MPOSOffline.Ext.config file
   3. If you want what you get in 3.2) with the addition of a few custom-built features, you can have some of the entries in the CommerceRuntime.MPOSOffline.Ext.config file.
   4. If you want what you get in 3.2) and all of your custom-built features, you should have the same entries in CommerceRuntime.MPOSOffline.Ext.config and CommerceRuntime.Ext.config

Notice that the config files are almost the same, with the one difference that the online version has 3 more handlers (ProductAvailability, PurchaseOrder related). Those are based on RTS calls which cannot be done in offline mode.

CommerceRuntime.exe.config:

<?xml version="1.0" encoding="utf-8"?>
<commerceRuntimeExtensions>
  <composition>
    <!--New Handlers-->
    <add source="type" value="FOO.Commerce.Runtime.Extensions.Receipts.CustomReceiptsRequestHandler, FOO.Commerce.Runtime.Extensions.Receipts" />
    <add source="type" value="FOO.Commerce.Runtime.Extensions.Customer.CreateCustomerRequestHandler, FOO.Commerce.Runtime.Extensions.Customer" />
    <add source="type" value="FOO.Commerce.Runtime.Extensions.Customer.UpdateCustomerRequestHandler, FOO.Commerce.Runtime.Extensions.Customer" />
       <add source="type" value="FOO.Commerce.Runtime.Extensions.ProductAvailability.SaveCartRequestHandler, FOO.Commerce.Runtime.Extensions.ProductAvailability" />
       <add source="type" value="FOO.Commerce.Runtime.Extensions.ProductAvailability.ValidateCartForCheckoutRequestHandler, FOO.Commerce.Runtime.Extensions.ProductAvailability" />
       <add source="type" value="FOO.Commerce.Runtime.Extensions.PurchaseOrder.SavePurchaseOrderRealtimeRequestHandler, FOO.Commerce.Runtime.Extensions.PurchaseOrder" />
  
    <!--Extended Handlers-->
    <add source="type" value="FOO.Commerce.Runtime.Extensions.StoreWalkin.StoreHourWalkinDataService, FOO.Commerce.Runtime.Extensions.StoreWalkin" />

    <!--Extended Triggers-->
    <add source="type" value="FOO.Commerce.Runtime.Extensions.ReturnPolicy.GetSalesOrderDetailsByTransactionIdServiceTrigger, FOO.Commerce.Runtime.Extensions.ReturnPolicy" />
  </composition>
</commerceRuntimeExtensions>

CommerceRuntime.offline.exe.config:

<?xml version="1.0" encoding="utf-8"?>
<commerceRuntimeExtensions>
  <composition>
    <!--New Handlers-->
    <add source="type" value="FOO.Commerce.Runtime.Extensions.Receipts.CustomReceiptsRequestHandler, FOO.Commerce.Runtime.Extensions.Receipts" />
    <add source="type" value="FOO.Commerce.Runtime.Extensions.Customer.CreateCustomerRequestHandler, FOO.Commerce.Runtime.Extensions.Customer" />
    <add source="type" value="FOO.Commerce.Runtime.Extensions.Customer.UpdateCustomerRequestHandler, FOO.Commerce.Runtime.Extensions.Customer" />
  
    <!--Extended Handlers-->
    <add source="type" value="FOO.Commerce.Runtime.Extensions.StoreWalkin.StoreHourWalkinDataService, FOO.Commerce.Runtime.Extensions.StoreWalkin" />

    <!--Extended Triggers-->
    <add source="type" value="FOO.Commerce.Runtime.Extensions.ReturnPolicy.GetSalesOrderDetailsByTransactionIdServiceTrigger, FOO.Commerce.Runtime.Extensions.ReturnPolicy" />
  </composition>
</commerceRuntimeExtensions>