How to proper inject dependency using swinject - ios

Question

I'm trying to inject dependency using Swinject, and I have no clue what I'm doing wrong.
I have protocol, that handles registring user.
protocol AuthServiceProtocol {
func registerUser(email: String, password: String, completion: #escaping CompletionHandler) }
and a class that conforms to this protocol make all the logic:
class AuthService: AuthServiceProtocol {
func registerUser(email: String, password: String, completion: #escaping CompletionHandler) {
let lowerCaseMail = email.lowercased()
let body: [String: Any] = [
"email": lowerCaseMail,
"password" : password
]
Alamofire.request(URL_REGISTER, method: .post, parameters: body, encoding: JSONEncoding.default, headers: HEADER).responseString { (response) in
if response.result.error == nil {
completion(true)
} else {
completion(false)
debugPrint(response.result.error as Any)
}
}
}
}
so, in AppDelegate we register container and it looks like:
let container = Container() { container in
container.register(AuthServiceProtocol.self) { _ in AuthService() }.inObjectScope(.container)
container.register(CreateAccountVC.self) { r in
let controller = CreateAccountVC()
controller.authService = r.resolve(AuthServiceProtocol.self)
return controller
}
}
but in CreateAccountVC authService is empty. Any ideas how can i do it?
CreateAccountVC is a subclass of ViewController, i have try'ed it by property, and constructors, but it's nil all the time.

Answer 1

Check your code:
var container : Container {
let container = Container()
container.register(AuthServiceProtocol.self) { _ in AuthService() }.inObjectScope(.container)
container.register(CreateAccountVC.self) { r in
let controller = CreateAccountVC()
controller.authService = r.resolve(AuthServiceProtocol.self)
print(r.resolve(AuthServiceProtocol.self))
return controller
}
return container
}
You have computed property and every time you call it, it creates a NEW Container object.
Refactor your code to have a single Container and I believe you will be good to go.
EDIT:
Here's a working code snippet.
Below is a small wrapper class to abstract concrete DI service (in case Swinject is one day replace by something else):
import Swinject
public class ConfigurationProvider {
// Currently using Swinject
private let backingService = Container()
// Singleton
public static let shared = ConfigurationProvider()
// Hidden initializer
private init() {}
// MARK: - Bind / Resolve
public func bind<T>(interface: T.Type, to assembly: T) {
backingService.register(interface) { _ in assembly }
}
public func resolve<T>(interface: T.Type) -> T! {
return backingService.resolve(interface)
}
}
// Extension methods to ignore 'shared.' call, like:
// ConfigurationProvider.bind(interface: IAssembly, to: Assembly())
// ConfigurationProvider.resolve(interface: IAssembly)
public extension ConfigurationProvider {
static func bind<T>(interface: T.Type, to assembly: T) {
ConfigurationProvider.shared.bind(interface: interface, to: assembly)
}
static func resolve<T>(interface: T.Type) -> T! {
return ConfigurationProvider.shared.resolve(interface: interface)
}
}
Usage:
class RSAuthLoginModuleAssembly: IAuthLoginModuleAssembly {
}
// Register:
ConfigurationProvider.bind(interface: IAuthLoginModuleAssembly.self, to: ConcreteAuthLoginModuleAssembly())
// Resolve:
guard let assembly = ConfigurationProvider.resolve(interface: IAuthLoginModuleAssembly.self) else {
throw NSError(domain: "Assembly cannot be nil", code: 999, userInfo: nil)
}