Restkit: Stubs for foreign key relationships

Question

I am having serious trouble understanding how to map the user and team objects given the two REST API endpoints below. I've been reading all I could find on SO, the closest QA was this one RestKit: Creating stubs for foreign key relationships, but I am having trouble adapting it to my case.

/users

 {
      "success": 1,
      "users": [{
           "success": 1,
           "name": "Damjan",
           "surname": "Mozetič",
           "teams": [1, 2]
      }]
 }

/teams

 {
      "success": 1,
      "teams": [{
          "id": 1,
          "title": "Team name",
          "user": 1  
      }]
 }

User.swift

class User: NSManagedObject {
    @NSManaged var userId: NSNumber
    @NSManaged var firstName: String
    @NSManaged var lastName: String

    @NSManaged var teams: NSSet?

    @NSManaged var teamFKIds: NSNumber? // FK
}

Team-swift

class Team: NSManagedObject {
    @NSManaged var teamId: NSNumber
    @NSManaged var title: String

    @NSManaged var user: User?
}

Mappings:

// User
let userMapping = RKEntityMapping(forEntityForName: "User", inManagedObjectStore: mos)
userMapping.identificationAttributes = ["userId"]
userMapping.addAttributeMappingsFromDictionary([
    "id": "userId",
    "name": "firstName",
    "surname": "lastName",
    "team": "teamName",
    "teams": "teamFKIds"
])
objectManager.addResponseDescriptor(RKResponseDescriptor(mapping: userMapping, method: .GET, pathPattern: "users", keyPath: nil, statusCodes: RKStatusCodeIndexSetForClass(.Successful)))

// Team
let teamMapping = RKEntityMapping(forEntityForName: "Team", inManagedObjectStore: mos)
teamMapping.identificationAttributes = ["teamId"]
teamMapping.addAttributeMappingsFromDictionary([
    "id": "teamId",
    "title": "title"
])
objectManager.addResponseDescriptor(RKResponseDescriptor(mapping: teamMapping, method: .GET, pathPattern: "teams", keyPath: nil, statusCodes: RKStatusCodeIndexSetForClass(.Successful)))

userMapping.addConnectionForRelationship("teams", connectedBy: ["teamFKIds": "teamId"])

From what I've been reading, creating stubs for FKs is the way to go, something like this, altough I know I've messed this up a bit:

let profileStubMapping = RKEntityMapping(forEntityForName: "Profile", inManagedObjectStore: mos)
userStubMapping.addPropertyMapping(RKAttributeMapping(fromKeyPath: nil, toKeyPath: "teamFKIds"))
userStubMapping.identificationAttributes = ["userId"]
objectManager.addResponseDescriptor(RKResponseDescriptor(mapping: userStubMapping, method: .Any, pathPattern: "teams", keyPath: "userId", statusCodes: RKStatusCodeIndexSetForClass(.Successful)))

Can someone please help me understand how to properly set this up?

Also, another question. Ultimately my plan is to retrieve the whole graph into Core Data. How do I achieve this? Would simply calling getObjectsAtPath for "/users" and "/teams" do the job?

Lastly I plan on havnig the thing work offline and sync when getting online. Any tips on implementing it?

Thank you.

Are you always getting users first and then teams? It seems you just need stubs via a nil keypath mapping and that's it... — Wain, Sep 26 '15 at 10:52
@Wain Yes, I do get users first. Can you show me how to setup the stubs via nil keypath? This is the part I have difficulty understanding. — Rhuantavan, Sep 26 '15 at 10:55

score 1 · Accepted Answer · answered Sep 26 '15 at 16:16

It looks like you want something along the lines of:

let userMapping = RKEntityMapping(forEntityForName: "User", inManagedObjectStore: mos)
userMapping.identificationAttributes = ["userId"]
userMapping.addAttributeMappingsFromDictionary([
    "id": "userId",
    "name": "firstName",
    "surname": "lastName"
])

let teamStubMapping = RKEntityMapping(forEntityForName: "Team", inManagedObjectStore: mos)
teamStubMapping.addPropertyMapping(RKAttributeMapping(fromKeyPath: nil, toKeyPath: "teamId"))
teamStubMapping.identificationAttributes = ["teamId"]

userMapping.addRelationshipMapping(sourceKeyPath: "teams", mapping: teamStubMapping)

Restkit: Stubs for foreign key relationships

1 Answers1