this class is not key value coding-compliant for the key Text using RestKit v0.20.0

Question

For 2 days now, I've been trying to find out why I'm getting the error using iOS 6.1.3 with Xcode 4.6.2 and RestKit 0.20.0:

"...this class is not key value coding-compliant for the key Text."

The strange part is that I can receive (GET) the JSON object fine. The error happens when I create my sample SignalMessage object and then try to PUT it back to the server.

The JSON is as follows:

{"Text":"New Message","HasMessage":"true"}

The SignalMessage object looks like this:

#import <Foundation/Foundation.h>

@interface SignalMessage : NSObject {

}

@property (nonatomic, copy) NSString *signalText;
@property (nonatomic, retain) NSNumber *isHasMessage;

@end

And the implementation like this:

#import "SignalMessage.h"

@implementation SignalMessage

@synthesize isHasMessage, signalText;

@end

My correctly working getMessage function looks like this:

- (IBAction)getMessage:(id)sender;
{
    NSLog(@"%@", @"Getting message... ");

    NSURL *url = [NSURL URLWithString:@"http://ec2-54-243-148-145.compute-1.amazonaws.com/TabletPractice/api/signal?clientIdentifier=2"];

    RKObjectManager *manager =  [RKObjectManager managerWithBaseURL:url];

    RKObjectMapping *responseMapping = [RKObjectMapping mappingForClass:[SignalMessage class]];
    [responseMapping addAttributeMappingsFromDictionary:@{@"Text":@"signalText", @"HasMessage": @"isHasMessage"}];
    RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:responseMapping pathPattern:nil keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];

    [manager addResponseDescriptor:responseDescriptor];

    [manager getObject:nil path:@"" parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *result)
    {
        NSArray *theresults = [result array];
        for (SignalMessage *item in theresults) {
            self.txtMessage.text = item.signalText;
            [self hideControls];
        }
    }  failure:^(RKObjectRequestOperation * operation, NSError * error)
     {
         NSLog (@"Server WS call failure: operation: %@ \n\nerror: %@", operation, error);
     }];
}

And here is the sendClicked message that gives me grieve:

- (IBAction)btnSendClicked:(id)sender;
{
    if ([txtMessage.text length] < 1)
        return;

    NSURL *url = [NSURL URLWithString:@"http://ec2-54-243-148-145.compute-1.amazonaws.com/TabletPractice/api/signal?clientIdentifier=2"];
    RKObjectManager *manager =  [RKObjectManager managerWithBaseURL:url];
    RKObjectMapping *requestMapping = [RKObjectMapping requestMapping];
    [requestMapping addAttributeMappingsFromDictionary:@{@"Text":@"signalText", @"HasMessage": @"isHasMessage"}];
    RKRequestDescriptor *requestDescriptor = [RKRequestDescriptor requestDescriptorWithMapping:requestMapping
                                                                                   objectClass:[SignalMessage class]
                                                                                   rootKeyPath:@""];
    [manager addRequestDescriptor:requestDescriptor];

    SignalMessage *newMessage = [[SignalMessage alloc] init];
    newMessage.signalText = @"Test Message";
    BOOL isMsg = TRUE;
    NSNumber *boolAsNumber = [NSNumber numberWithBool:isMsg];
    newMessage.isHasMessage = boolAsNumber;

    [manager putObject:newMessage path:@"" parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *result) {
        NSLog(@"We object mapped the response with the following result: %@", result);
    }  failure:^(RKObjectRequestOperation * operation, NSError * error)
     {
         NSLog (@"Server WS call failure: operation: %@ \n\nerror: %@", operation, error);
     }];

    [self hideControls];
}

At this point, I'm at a loss.

Answer 1

Please add a inverse mapping to your RKRequestDescriptor in your btnSendClicked method like below:

RKRequestDescriptor *requestDescriptor = [RKRequestDescriptor      
  requestDescriptorWithMapping:[requestMapping inverseMapping]
                   objectClass:[SignalMessage class]
                   rootKeyPath:@""];