Refactoring Code in Swift - swift

Question

I have a pretty standard problem here that I am a little confused how to make more elegant in the swift tradition of things.
I have a base URL string in my APIClient, a path for different methods to use, and methods might pass in a optional string.
How do I write this such that it is much cleaner? I feel like I am writing swift code but not using any of the new constructs (like guard, let), etc.
// call the API
ApiClient.sharedInstance.getUser("56cfffce227a6c2c9b000001", successCompletion: successCompletion, failureCompletion: failureCompletion)
// setting the current URL
let currentURL = String("http://localhost:3000")
// class definition
class ApiClient {
var baseURL:String!;
// have to init the string class for the
init (base:String){
self.baseURL = base
}
class var sharedInstance: ApiClient {
struct Static{
static let instance = ApiClient(base: currentURL)
}
return Static.instance
}
func getUser(user_id: String?, successCompletion: ResultHandler<User>, failureCompletion:ResultHandler<FailureReason>){
// this is awkward
var url: URLStringConvertible!
// this is even more awkward
if user_id != nil {
url = "\(currentURL)/users/\(user_id!).json"
} else {
url = "\(currentURL)/users/me"
}
}
}

Answer 1

Cleaned some things up and removed some unnecessary forced-unwraps.
class ApiClient {
var baseURL: String;
// have to init the string class for the
init (base:String){
self.baseURL = base
}
class var sharedInstance: ApiClient {
struct Static{
static let instance = ApiClient(base: currentURL)
}
return Static.instance
}
func getUser(user_id: String?, successCompletion: ResultHandler<User>, failureCompletion:ResultHandler<FailureReason>){
var url: URLStringConvertible
if let user_id = user_id {
url = "\(currentURL)/users/\(user_id!).json"
}
else{
url = "\(currentURL)/users/me"
}
}
Depending on what you're doing in getUser, things could be done differently.
FYI, what I tend to do for singletons: (arguably not the best):
private static var realSharedInstance: Class?
static var sharedInstance: Class {
get {
if let realSharedInstance = realSharedInstance {
return realSharedInstance
}
else{
realSharedInstance = Class()
return realSharedInstance!
}
}
}

Answer 2

For me, I like to create an Endpoint for every endpoint that the API supports. In this case, a UsersEndpoint which can make requests via APIClient.
This is easier to scale (for me) when there more endpoints and each endpoint has multiple resources.
Use in code:
MyAPI.sharedInstance.users.getUser(id, parameters: params, success: {}, failure: {})
MyAPI.sharedInstance.anotherEndpoint.doSomething(parameters: params, success: {}, failure: {})
The classes:
class MyAPI {
static let sharedInstance = MyAPI()
let users: UsersEndpoint
// more endpoints here
init() {
users = UsersEndpoint()
// ....
}
}
class APIClient {
static let sharedClient = APIClient()
var manager : Alamofire.Manager!
var baseURL: String
init() {
baseURL = String(format: "https://%#%#", self.instanceUrl, API.Version)
}
func get(endpoint endpoint: String,
parameters: [String:AnyObject],
success: SuccessCallback,
failure: FailureCallback) {
let requestUrl = NSURL(string: "\(self.baseURL)\(endpoint)")!
manager.request(.GET, requestUrl, parameters: parameters, headers: headers)
.validate()
.responseData { response in
switch response.result {
case .Success(let value):
if let data: NSData = value {
success(data: data)
log.verbose("Success - GET requestUrl=\(requestUrl)")
}
break;
case .Failure(let error):
failure(error: error)
log.error("Failure - GET requestUrl=\(requestUrl)\nError = \(error.localizedDescription)")
break;
}
}
}
}
class APIFacade {
var endpoint: String
init(endpoint: String) {
self.endpoint = endpoint;
}
func get(endpoint endpoint: String,
parameters: [String:AnyObject],
success: SuccessCallback,
failure: FailureCallback) {
APIClient.sharedClient.get(endpoint: endpoint, parameters: parameters, success: success, failure: failure)
}
}
class UsersEndpoint: APIFacade {
init() {
super.init(endpoint: "/users")
}
func getUser(id: String, parameters: [String:AnyObject], success: SuccessCallback, failure: FailureCallback) {
super.get(endpoint: "\(self.endpoint)/\(id)", parameters: parameters, success: success, failure: failure)
}
}