Support generic value transformation in mappings

Classes/NSManagedObject+Mappings.m

@@ -24,6 +24,8 @@
 #import "NSManagedObject+ActiveRecord.h"
 #import "ObjectiveSugar.h"
 
+typedef id (^TransformBlock)(id value, NSManagedObjectContext *context);
+
 @implementation NSManagedObject (Mappings)
 
 + (NSString *)keyForRemoteKey:(NSString *)remoteKey inContext:(NSManagedObjectContext *)context {
@@ -46,6 +48,11 @@ + (NSString *)keyForRemoteKey:(NSString *)remoteKey inContext:(NSManagedObjectCo
 }
 
 + (id)transformValue:(id)value forRemoteKey:(NSString *)remoteKey inContext:(NSManagedObjectContext *)context {
+    if ([self cachedMappings][remoteKey][@"transform"]) {
+        TransformBlock transformer = [self cachedMappings][remoteKey][@"transform"];
+        return transformer(value, context);
+    }
+
     Class class = [self cachedMappings][remoteKey][@"class"];
     if (class)
         return [self objectOrSetOfObjectsFromValue:value ofClass:class inContext:context];

Example/SampleProject.xcodeproj/xcshareddata/xcschemes/SampleProject.xcscheme

@@ -14,7 +14,7 @@
             buildForAnalyzing = "YES">
             <BuildableReference
                BuildableIdentifier = "primary"
-               BlueprintIdentifier = "92C36FE96BF5420EBF7F892F"
+               BlueprintIdentifier = "B856C4C9923B4EC7A757D776"
                BuildableName = "libPods.a"
                BlueprintName = "Pods"
                ReferencedContainer = "container:Pods/Pods.xcodeproj">
@@ -28,7 +28,7 @@
             buildForAnalyzing = "YES">
             <BuildableReference
                BuildableIdentifier = "primary"
-               BlueprintIdentifier = "87598C52275746D1A1FE32AE"
+               BlueprintIdentifier = "8B11F5055ECD4BB49B3C08A4"
                BuildableName = "libPods-SampleProjectTests.a"
                BlueprintName = "Pods-SampleProjectTests"
                ReferencedContainer = "container:Pods/Pods.xcodeproj">

Example/SampleProject/Models/Categories/Car+Mappings.m

@@ -23,10 +23,13 @@ + (NSDictionary *)mappings {
             @"class": [InsuranceCompany class]
         },
         @"insurance_company": @{
-                @"key": @"insuranceCompany",
-                @"class": [InsuranceCompany class]
-                }
-
+            @"key": @"insuranceCompany",
+            @"transform": ^id(NSDictionary *value, NSManagedObjectContext *context) {
+                InsuranceCompany * company = [InsuranceCompany findOrCreate:@{@"remoteID": value[@"id"] ?: value[@"remoteID"]} inContext:context];
+                [company update:value];
+                return company;
+            }
+        }
     };
 }
 

Example/SampleProjectTests/MappingsTests.m

@@ -73,6 +73,11 @@
         Person *bob = [Person findOrCreate:@{ @"first_name": @"Bob" }];
         [[bob.firstName should] equal:@"Bob"];
     });
+
+    it(@"uses mappings to transform values", ^{
+        Car *car = [Car create:@{ @"hp": @150, @"insurance_company": @{ @"name" : @"Farmers", @"remoteID" : @4567 } }];
+        [[car.insuranceCompany.name should] equal:@"Farmers"];
+    });
 
     it(@"supports creating a parent object using just ID from the server", ^{
         Car *car = [Car create:@{ @"hp": @150, @"insurance_id": @1234 }];