Resource+Extensions.swift

import BrightFutures

extension Resource {
    
    func addLinkData<T: Resource>(resources: [T]) -> Future<Self, SpineError> {
        let url = SpineSingleton.router.baseURL.appendingPathComponent("/\(self.resourceType)/\(self.id!)/relationships/\(resources.first!.resourceType)")
        let payload = try! SpineSingleton.serializer.serializeLinkData(resources)
        return performRequest(method: "POST", url: url, payload: payload)
    }
    
    func removeLinkData<T: Resource>(resources: [T]) -> Future<Self, SpineError> {
        let url = SpineSingleton.router.baseURL.appendingPathComponent("/\(self.resourceType)/\(self.id!)/relationships/\(resources.first!.resourceType)")
        let payload = try! SpineSingleton.serializer.serializeLinkData(resources)
        return performRequest(method: "DELETE", url: url, payload: payload)
    }
}

import SwiftyJSON

extension Resource {

    func performRequest(method: String, url:URL, payload:Data? = nil) -> Future<Self, SpineError> {
        let promise = Promise<Self, SpineError>()
        
        SpineSingleton.networkClient.request(method: method, url: url, payload: payload) { (statusCode, responseData, networkError) in
            
            if statusCodeIsSuccess(statusCode) {
                let response = JSON(data: responseData!)
                print("Perform request success: \(response)")
                promise.success(self)
            } else if let error = networkError {
                promise.failure(SpineError.networkError(error))
            } else if let safeResponseData = responseData {
                do {
                    let doc = try SpineSingleton.serializer.deserializeData(safeResponseData)
                    let error = SpineError.serverError(statusCode: statusCode!, apiErrors: doc.errors)
                    promise.failure(error)
                } catch _ {
                    promise.failure(SpineError.unknownError)
                }
            }
        }
        
        return promise.future
    }
}