Display Restkit properties Error on conversion error

Question

This is what my sample code looks like:

{ "name": "Ahmad Mansour", "subjects": [ { "parent_subject_name": "Arabic", "subject_name": "Shafahi", "exams": [ { "score": "30.00", "exam_name": "Sa3i 1 " }, { "score": "50.00", "exam_name": "sa3i 2" }, { "score": "100.00", "exam_name": "First Semester Exam" } ] }, { "parent_subject_name": "Arabic", "subject_name": "Khati", "exams": [ { "score": "50.00", "exam_name": "Sa3i 1 " }, { "score": "60.00", "exam_name": "sa3i 2" }, { "score": "95.00", "exam_name": "First Semester Exam" } ] }, 

for subject . My mapping works fine:

 RKEntityMapping *subjectEntityMapping = [RKEntityMapping mappingForEntityForName:kSubjectIdentity inManagedObjectStore:model.managedObjectStore]; [subjectEntityMapping addAttributeMappingsFromDictionary:@{ @"subject_name": @"name", @"parent_subject_name" :@"parent_name" }]; subjectEntityMapping.identificationAttributes = @[ @"name" ]; RKResponseDescriptor *studentResponseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:subjectEntityMapping pathPattern:kGradesPath keyPath:@"subjects" statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)]; [model.objectManager addResponseDescriptor:studentResponseDescriptor]; 

but when I do an exam score card .. things explode:

 RKEntityMapping *examEntityMapping = [RKEntityMapping mappingForEntityForName:kExamIdentity inManagedObjectStore:model.managedObjectStore]; [examEntityMapping addAttributeMappingsFromDictionary:@{ @"exams.exam_name": @"name" }]; examEntityMapping.identificationAttributes = @[ @"name" ]; RKResponseDescriptor *examResponseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:examEntityMapping pathPattern:kGradesPath keyPath:@"subjects" statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)]; [model.objectManager addResponseDescriptor:examResponseDescriptor]; 

I get the following error:

  E restkit.object_mapping:RKMappingOperation.m:431 Failed transformation of value at keyPath 'exams.exam_name' to representation of type 'NSString': Error Domain=org.restkit.RKValueTransformers.ErrorDomain Code=3002 "Failed transformation of value '( "Sa3i 1 ", "sa3i 2", "First Semester Exam" )' to NSString: none of the 2 value transformers consulted were successful." UserInfo=0x9a508a0 {detailedErrors=( "Error Domain=org.restkit.RKValueTransformers.ErrorDomain Code=3002 \"The given value is not already an instance of 'NSString'\" UserInfo=0x9a50800 {NSLocalizedDescription=The given value is not already an instance of 'NSString'}", "Error Domain=org.restkit.RKValueTransformers.ErrorDomain Code=3000 \"Expected an `inputValue` of type `NSNull`, but got a `__NSArrayI`.\" UserInfo=0x9a50830 {NSLocalizedDescription=Expected an `inputValue` of type `NSNull`, but got a `__NSArrayI`.}" 

I also tried this mapping, but I get exactly the same error:

 [examEntityMapping addAttributeMappingsFromDictionary:@{ @"exam_name": @"name" }]; examEntityMapping.identificationAttributes = @[ @"name" ]; RKResponseDescriptor *examResponseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:examEntityMapping pathPattern:kGradesPath keyPath:@"subjects.exams" statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)]; 

ideas?

Answer 1

You must not have an answer descriptor for exams. This is nested data in your object, so it should be displayed using a relation to the display of the object.

Using a response descriptor does not work because you are trying to map to 2 arrays when matching is only used for one. Therefore, you get an error when RestKit tries to convert an array to a string.

In addition, for your comparison of exams, you should probably specify several attributes for a unique identifier, as exam names are reused for different instances ...