Examples showing how to query for object relations from loopback SDK

[osunacons]

Hi,

I am trying to query a loopback server for relations between models, I have a "Users" Model and an "Cars" model, and a has me nay relation between them, so I can query for all items in a section with /users/:id/cars from a rest client.

any documentation or code examples?

[vikmeup]

any status on this?

I would like to see examples as well

[hideya]

Although iOS SDK doesn't directly support relations yet, I hope the following post may help: Issue https://github.com/strongloop/loopback-sdk-ios/issues/2 -- Examples showing how to query for object relations from loopback SDK (NOTE: now you need to subclass LBPersistedModel instead of LBModel if you are using the code from the master).

I'd like to have SDK to support relations directly and would like to work on it as a part of iOS SDK work.

[jubbens]

@carliwis @hideya As noted in the referenced issue, the workaround does not work. This is because you need to create a new item for your relation to the repository contract. This Swift example allows you to reference /users/:id/cars as you expect:

In class userRepository:LBPersistedModelRepository:

override func contract() -> SLRESTContract! {
  let contract = super.contract()
  contract.addItem(SLRESTContractItem.init(pattern: "/\(self.className)/:id/cars", verb: "GET"), forMethod: "\(self.className).prototype.cars")

  return contract
}

And to retrieve related Car:LBPersistedModels from a User:LBPersistedModel:

self.invokeMethod("cars", parameters: ["id": self._id], success: { models in
  var cars:[Car] = []

  models.enumerateObjectsUsingBlock({ object, idx, stop in
    cars.append(carsRepository.modelWithDictionary(object as! [NSObject : AnyObject]) as! Car)
  })

  // Do something with cars
}, failure: { (error: NSError!) -> Void in
  // Handle the error
})