RxSwift and three API requests - ios

Question

I want to fetch a data from three different APIs, and then save it in a database. Therefore, data from each query should be separated after the operation.
How to do it with RxSwift? Zip? In my example I'm using only two URLs, but it's just example.
QueryService:
import Foundation
import RxSwift
class QueryService {
let albumsURL = URL(string: "https://jsonplaceholder.typicode.com/albums")!
func fetchAlbums() -> Observable<[Album]> {
return Observable.create { observer -> Disposable in
let task = URLSession.shared.dataTask(with: self.albumsURL) { data, _, _ in
guard let data = data else {
observer.onError(NSError(domain: "", code: -1, userInfo: nil))
return
}
do {
let albums = try JSONDecoder().decode([Album].self, from: data)
observer.onNext(albums)
} catch {
observer.onError(error)
}
}
task.resume()
return Disposables.create{
task.cancel()
}
}
}
func fetchUsers() -> Observable<[User]> {
return Observable.create { observer -> Disposable in
let task = URLSession.shared.dataTask(with: URL(string: "https://jsonplaceholder.typicode.com/users")!) { data, _, _ in
guard let data = data else {
observer.onError(NSError(domain: "", code: -1, userInfo: nil))
return
}
do {
let users = try JSONDecoder().decode([User].self, from: data)
observer.onNext(users)
} catch {
observer.onError(error)
}
}
task.resume()
return Disposables.create{
task.cancel()
}
}
}
}

Answer 1

I'm assuming you're trying to execute two tasks in parallel and want to reach their results from a single observable.
If this is the case, your code should be like this:
Observable.zip(service.fetchAlbums(), service.fetchUsers())
.subscribe(onNext: { (albums, users) in
print(albums)
print(users)
})
.disposed(by: self.disposeBag)