Map only on element of a one to many relationships - ios

Question

I'm stuck with the following problem. I have a relationships one_to_many between a Event and Comment. One Event can have many Comment but a Comment has belongs_to only one Event.
Until here, everything is fine. Now, when I'm adding a comment, I would like to map only this new comment. That means I'm using my relationship from Comment to Moment.
I have some troubles with the mapping that I'm not able to solve. My error is at the end of this post after all the description.
I'm receiving this JSON:
"comment": {
"id": 17,
"commentable_id": 12,
"commentable_type": "Moment",
"content": "That's it ! ",
"created_at": "2014-06-20T18:17:42Z",
"updated_at": "2014-06-20T18:17:42Z",
"user_id": 1,
"creator": {
"id": 1,
"email": "test#test.com",
"firstname": "Bobby",
"lastname": "Stouket",
"gender": 0,
"created_at": "2014-04-06T17:48:11Z",
"updated_at": "2014-06-20T18:17:26Z"
}
}
Here is my comment mapping:
RKEntityMapping *commentMapping = [RKEntityMapping mappingForEntityForName:#"Comment" inManagedObjectStore:store];
commentMapping.identificationAttributes = #[ #"commentId"];
[commentMapping addAttributeMappingsFromDictionary:#{
#"id" : #"commentId",
#"updated_at": #"updatedAt",
#"created_at": #"createdAt",
#"user_id": #"userId",
#"commentable_id": #"commentableId",
#"commentable_type": #"commentableType",
#"content": #"content"
}];
RKEntityMapping *userCreatorMapping = [APICallUser RKGetUserMappingOnlyWithAvatarForManagedObjectStore:store];
[commentMapping addConnectionForRelationship:#"creator" connectedBy:#{#"userId": #"userId"}];
[commentMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"creator"
toKeyPath:#"creator"
withMapping:userCreatorMapping]];
Here is my code for my moment mapping (with the association with comments which is working) :
RKEntityMapping *momentMapping = [RKEntityMapping mappingForEntityForName:#"Moment" inManagedObjectStore:store];
momentMapping.identificationAttributes = #[ #"momentId"];
[momentMapping addAttributeMappingsFromDictionary:#{
#"id" : #"momentId",
#"creator.id" : #"creatorId",
#"created_at" : #"createdAt",
#"updated_at" : #"updatedAt"
}];
RKEntityMapping *commentMapping = [APICallComment RKGetCommentMappingForManagedObjectStore:store];
[commentMapping addConnectionForRelationship:#"moment" connectedBy:#{#"commentableId":#"momentId"}];
[momentMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"comments"
toKeyPath:#"comments"
withMapping:commentMapping]];
There is one more thing to know is that a comment can be on a moment or on a photo. According to my JSON, I don't think I need an RKDynamicMapping but I'm not sure.
Here is the code when I'm using my mapping. The request is send successfully and I receive the JSON written before.
KEntityMapping *commentMapping = [APICallComment RKGetCommentMappingForManagedObjectStore:self.appDelegate.managedObjectStore];
RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:commentMapping
method:RKRequestMethodPOST
pathPattern:APICallCommentCreateCommentsRouteName
keyPath:#"comment"
statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
[session.objectManager addResponseDescriptor:responseDescriptor];
//session.objectManager.requestSerializationMIMEType=RKMIMETypeJSON;
Error Domain=org.restkit.RestKit.ErrorDomain Code=1001 "No mappable object representations were found at the key paths searched." UserInfo=0xb8a9150 {DetailedErrors=(), NSLocalizedFailureReason=The mapping operation was unable to find any nested object representations at the key paths searched: comments, device, devices
The representation inputted to the mapper was found to contain nested object representations at the following key paths: comment
This likely indicates that you have misconfigured the key paths for your mappings., NSLocalizedDescription=No mappable object representations were found at the key paths searched., keyPath=null}
Edit:
Here is the result of the code line session.objectManager.requestDescriptor. It's really weird. I can see only 1 object in the NSArray. When I print it I can read:
Printing description of $1:
<__NSArrayI 0xbd61010>(
<RKRequestDescriptor: 0xbd12bb0 method=(POST) objectClass=BasicLocation rootKeyPath=position : <RKObjectMapping:0xbd40b70 objectClass=NSMutableDictionary propertyMappings=(
"<RKAttributeMapping: 0xbd545d0 latitude => lat>",
"<RKAttributeMapping: 0xbd58430 longitude => lng>"
)>>
)
Nowhere I've written that positionshould be the rootKeyPath and my other attributes are not here (content, commentableType, userId, createdAt, updatedAt, commentId).
Thank you for your help.

Answer 1

You create:
RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:commentMapping
method:RKRequestMethodPOST
pathPattern:APICallCommentCreateCommentsRouteName
keyPath:#"comment"
statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
but you can't ever add it to the object manager, because it only understands comments, device, devices.
That would seem to be your main issue.
You wouldn't usually do this:
[commentMapping addConnectionForRelationship:#"creator" connectedBy:#{#"userId": #"userId"}];
[commentMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"creator"
toKeyPath:#"creator"
withMapping:userCreatorMapping]];
because you are supplying 2 different mappings for exactly the same content and relationship where you only need one because the user information is nested inside the comment information. So, you can remove the foreign key mapping (addConnectionForRelationship:).

Answer 2

The mapping was good but the mistake comes from here:
[RKResponseDescriptor responseDescriptorWithMapping:commentMapping
method:RKRequestMethodGET
pathPattern:HERE
keyPath:#"comment"
statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
I didn't write the path pattern. This variable changed and everything works perfectly.