How can I return all the response from API to my Swift app - swift

Question

I'am learning swift and I see an example here https://matteomanferdini.com/network-requests-rest-apis-ios-swift/ and Im trying to change the code for something that work for me.
this is how the original code looks
struct Wrapper<T: Decodable>: Decodable {
let items: [T]?
}
protocol NetworkRequest: AnyObject {
associatedtype ModelType
func decode(_ data: Data) -> ModelType?
func load(withCompletion completion: #escaping (ModelType?) -> Void)
}
extension NetworkRequest {
fileprivate func load(_ url: URLRequest, withCompletion completion: #escaping (ModelType?) -> Void) {
let session = URLSession(configuration: .default, delegate: nil, delegateQueue: .main)
let task = session.dataTask(with: url, completionHandler: { [weak self] (data: Data?, response: URLResponse?, error: Error?) -> Void in
if let error = error {
print("Error: \(error)")
}
guard let data = data else {
completion(nil)
return
}
completion(self?.decode(data))
})
task.resume()
}
}
class APIRequest<Resource: APIResource> {
let resource: Resource
init(resource: Resource) {
self.resource = resource
}
}
extension APIRequest: NetworkRequest {
func decode(_ data: Data) -> [Resource.ModelType]? {
let wrapper = try? JSONDecoder().decode(Wrapper<Resource.ModelType>.self, from: data)
return wrapper?.items
}
func load(withCompletion completion: #escaping ([Resource.ModelType]?) -> Void) {
load(resource.request, withCompletion: completion)
}
}
but what I need to change the structure Wrapper to
struct Wrapper<T: Decodable>: Decodable {
let items: [T]?
let response: Bool?
let message: String?
}
and return items, response and message not only items

Answer 1

In this case you don't need the protocol at all because you want to get the root object.
This is sufficient
struct Wrapper<T: Decodable>: Decodable {
let items: [T]
let response: Bool
let message: String
}
class NetworkRequest {
func load<T : Decodable>(_ request: URLRequest, withCompletion completion: #escaping (Result<Wrapper<T>,Error>) -> Void) {
let session = URLSession(configuration: .default, delegate: nil, delegateQueue: .main)
let task = session.dataTask(with: request) { data, _, error in
if let error = error {
completion(.failure(error))
} else {
completion( Result {try JSONDecoder().decode(Wrapper<T>.self, from: data!)})
}
}
task.resume()
}
}
The completion handler returns a Result object, on success the wrapper object and on failure all errors.
In the wrapper struct declare all properties non-optional to get error messages and change only those to optional which really can be nil.

Answer 2

I change the code like this
class NetworkRequest<Resource: APIResource> {
let resource: Resource
init(resource: Resource) {
self.resource = resource
}
func load(withCompletion completion: #escaping (Result<Wrapper<Resource.ModelType>,Error>) -> Void) {
let session = URLSession(configuration: .default, delegate: nil, delegateQueue: .main)
let task = session.dataTask(with: self.resource.request) { data, _, error in
if let error = error {
completion(.failure(error))
} else {
completion( Result {try JSONDecoder().decode(Wrapper<Resource.ModelType>.self, from: data!)})
}
}
task.resume()
}
}
struct LoginResource: APIResource {
typealias ModelType = Token
let methodPath = "/users/login/"
let method = "post"
var params: [String: Any]?
init(username: String, password: String) {
self.params = ["username":username, "password": password]
}
}
In my view:
func login() {
if user == "" || password == "" {
self.title_alert = "Info"
message_alert = "Test Alert"
show_alert = true
return
}
let loginRequest = NetworkRequest(resource: LoginResource(username:user,password:password))
loginRequest.load { result in
switch result {
case .failure(let error):
print(error)
case .success(let data):
print(data)
}
}
}
I don't know if this is the best way but works Thank you #vadian