Handle a POST response with RestKit that is not mapped to the POST object

ios, objective-c, restkit, restkit-0.20

Solution

I'd just create a new object for your response and map your response to that.

Objects

@interface MYRequest : NSObject

@property NSNumber *prop1;
@property NSNumber *prop2;

@end

@interface MYResponse : NSObject

@property NSArray *data;
@property NSString *message;

@end

Mappings

RKObjectMapping *requestMapping = [RKObjectMapping requestMapping];
[requestMapping addAttributeMappingsFromArray:@[@"prop1", @"prop2"]];

RKObjectMapping *responseMapping = [RKObjectMapping mappingForClass:[MYResponse class]];
[requestMapping addAttributeMappingsFromArray:@[@"data", @"message"]];

Descriptors

RKRequestDescriptor *requestDescriptor = [RKRequestDescriptor requestDescriptorWithMapping:requestMapping
                                                                               objectClass:[MYRequest class]
                                                                               rootKeyPath:nil
                                                                                    method:RKRequestMethodPOST];

RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:responseMapping
                                                                                        method:RKRequestMethodPOST
                                                                                   pathPattern:@"items"
                                                                                       keyPath:nil
                                                                                   statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];

Object Manager

[self.objectManager addRequestDescriptor:requestDescriptor];
[self.objectManager addResponseDescriptor:responseDescriptor];

Execute

MYRequest *body = [MYRequest new];
[body setProp1:@123];
[body setProp2:@5];

[self.objectManager postObject:body
                          path:@"items"
                    parameters:nil
                       success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
                           MYResponse *result = [mappingResult firstObject];
                           NSLog(@"Data: %@\nMessage: %@", [result data], [result message]);
                       }
                       failure:^(RKObjectRequestOperation *operation, NSError *error) {
                           NSLog(@"Error: %@", error);
                       }];

Problem

I have a situation where I am doing a post of an object (not a managed one, just an NSObject derived one), but the response from the REST API is not a JSON representation of the kind of object being posted. It is something else altogether. Is it possible to handle this? Say I post an object (JSON): ``` { "prop1" : 123, "prop2" : 5 } ``` And the response if not an object with properties `prop1` and `prop2`, as RestKit expects by default, but something else: ``` { "data" : [1,2,3,4,5,6], "message" : "hello world" } ``` I've seen examples where operation.targetObject was set to nil, but (I believe) this is only in Core Data managed scenarios. I am trying something simple like this: ``` RKObjectRequestOperation *operation = [self.objectManager appropriateObjectRequestOperationWithObject:body method:RKRequestMethodPOST path:@"items" parameters:nil]; [operation setCompletionBlockWithSuccess:^(RKObjectRequestOperation *operation, RKMappingResult *result) { // success is called, but the result does not contain what the response JSON is } failure:^(RKObjectRequestOperation *operation, NSError *error) { // failure }]; [operation setWillMapDeserializedResponseBlock:^id(id deserializedResponseBody) { // deserializedResponseBody is always nil }]; [operation start]; ``` I thought I could be able to look at the response contents in the setWillMapDeserializedResponseBlock, but it is always nil. Because the posted object has `prop1` and `prop2` properties, and how RestKit works by default, it expects JSON with said properties. But, since the result has nothing to do with the posted object, `prop1` and `prop2` are just nil (which I don't care for anyway). By the way, I have setup the request mapping correctly, so the `body` being passes in the operation object is correctly mapping my NSObject and sending it in the correct JSON format to the server. Is there a way that I can make such a call with RestKit, and manually pull out what I am looking for on the success event? Even if it was a dictionary representation of the JSON response?

Original source