Overview

An object that adopts the RKMappingOperationDataSource protocol is responsible for the retrieval or creation of target objects within an RKMapperOperation or RKMappingOperation. A data source is responsible for meeting the requirements of the underlying data store implementation and must return a key-value coding compliant object instance that can be used as the target object of a mapping operation. It is also responsible for commiting any changes necessary to the underlying data store once a mapping operation has completed its work.

At a minimum, a data source must implement the mappingOperation:targetObjectForRepresentation:withMapping: method. This method is responsible for finding an existing object instance to be updated or creating a new object if no existing object could be found or the underlying data store does not support persistence. Object mapping operations which target NSObject derived classes will always result in mapping to new transient objects, while persistent data stores such as Core Data can be queried to retrieve existing objects for update.