Rules & Mappers Mappers

Configured Commerce Handlers

• Handlers are used for processing business logic in Configured Commerce
• They are derived from HandlerBase and use generics to utilize Parameter Object and Result Object pattern
• Handlers are dynamically loaded using DependencyName attribute, which is essential for adding or replacing handlers
• Order property determines the order of execution within the chain, lower number means higher precedence
• Default order for handlers is 500

Adding Handlers to the Chain

• The base code executes first followed by subsequent handlers in the chain
• Handlers with an order less than 500 will execute before the base handlers
• Ensure unique DependencyName for new handlers
• Reuse the DependencyName of the base handler to override it
• Breaking the handler chain can be done by returning the result directly instead of calling this.NextHandler.Execute() or setting the next handler to NullHandler

Overriding Handlers

• It's recommended to add handlers to the chain unless base functionality needs modification for a given implementation
• Set the DependencyName attribute on the handler class to the same name as the one intended to override
• If multiple handlers with the same DependencyName are registered, the one with the lower DependencyOrder will be used
• Handlers within the "Insite" namespace have a default DependencyOrder of 999, while those outside have 500
• The DependencyOrder can be customized using the DependencyOrder attribute

Passing Data to and from Handlers

• Every REST call can accept a dictionary of data in the properties field of BaseModel
• Query string data is also implicitly accepted as a properties dictionary
• To pass custom data to handlers use the properties dictionary within the ParameterBase derived service parameter object
• Custom data can be sent using query strings but requires overrides and is not recommended for ease of upgrades
• Child objects within resulting objects usually have the Properties dictionary populated with data from the corresponding service result child object
• To return arbitrary data from a REST call, use the Properties.Add method
• Use AddObjectToResultProperties to ensure the correct serialization for complex objects
• On the client, use JSON.parse to deserialize complex objects

Working with Promotions and Discounts: Retrieval

• The /api/v1/carts/{cartId}/promotions endpoint returns a collection of promotions applied to a cart
• POS /api/v1/carts/{cartId}/promotions endpoint applies promotions to a cart
• GET /api/v1/carts/{cartId}/promotions/{promotionId} endpoint returns a single promotion for a cart

Working with Promotions and Discounts: Custom Mappers and Line Level Data

• Create a custom mapper inheriting from GetCartLineMapper to retrieve promotions applied to a given line item
• Override the MapResult method and call the base method first
• Access the PromotionResult and Promotion properties from the GetCartLineResult object
• Add needed information to the Properties collection of the GetCartLineModel object

Working with Promotions and Discounts: Custom Mappers and Order Level vs. Line Level Data

• Create a custom mapper inheriting from GetPromotionMapper to retrieve promotions applied to a specific order
• Override the MapResult method and call the base method first
• Access the cartid from the incoming request
• Use the cartid to access the current cart using the CartService
• Iterate through CartLineResults to find matching promotions based on PromotionId
• Add orderLineId to the Properties collection of the PromotionModel if promotion applies to cart line level
• The orderLineId property in the promotion response indicates if the promotion applies to order or order line level
• If the property is null - the promotion applies at the order level
• If the property contains orderLineId - the promotion applies at the order line level
• The /api/v1/carts/current endpoint returns both order and order line level data
• The orderLineId property in the response helps distinguish between order and order line level promotions

This quiz covers the basic concepts of Configured Commerce Handlers used for processing business logic. It discusses how handlers are derived from HandlerBase, their execution order, and how to manage dependencies. Additionally, it includes information on adding and overriding handlers in the execution chain.