Adds a convenience to NSEntityDescription to allow specification of identifier key

Mobile Buy SDK/Mobile Buy SDK/Additions/NSEntityDescription+BUYAdditions.h

@@ -61,4 +61,9 @@
  */
 - (void)buy_updateObject:(id<BUYObject>)object withJSON:(NSDictionary *)JSON;
 
+/**
+ *  Convenience to access JSONPropertyKey for the "identifier" attribute
+ */
+@property (strong, nonatomic, readonly) NSString *JSONIdentifierKey;
+
 @end

Mobile Buy SDK/Mobile Buy SDK/Additions/NSEntityDescription+BUYAdditions.m

@@ -177,4 +177,11 @@
 	[object setValuesForKeysWithDictionary:results];
 }
 
+
+- (NSString *)JSONIdentifierKey
+{
+	NSAttributeDescription *attributeDescription = self.attributesByName[@"identifier"];
+	return attributeDescription.JSONPropertyKey ?: @"id";
+}
+
 @end