URLImageService+FetchImage.swift

//
//  URLImageService+FetchImage.swift
//
//  Created by Dmytro Anokhin on 09/01/2021.
//

import Foundation
import Combine
import URLImage


extension URLImageService {

    /// Helper function to get an image from the cache or load it from the network.
    ///
    /// Loading starts immediately and the completion closure executed on the main queue. Note: the closure can be exected before the function returns.
    /// You must retain the returned object and release it if you want to cancel loading.
    func fetchImage(_ url: URL,
                    options: URLImageOptions? = nil,
                    completion: @escaping (_ result: Result<ImageInfo, Error>) -> Void) -> Any {

        let remoteImage = makeRemoteImage(url: url, options: options)
        let cancellable = remoteImage.$loadingState.sink { loadingState in
            switch loadingState {
                case .initial:
                    break

                case .inProgress:
                    break

                case .success(let transientImage):
                    completion(.success(transientImage.info))

                case .failure(let error):
                    completion(.failure(error))
            }
        }

        remoteImage.load()

        return (remoteImage, cancellable)
    }
}


class Example {

    private var fetchImageToken: Any?

    func fetchImageExample() {
        let url = URL(string: "https://homepages.cae.wisc.edu/~ece533/images/lena.png")!

        fetchImageToken = URLImageService.shared.fetchImage(url) { result in
            switch result {
                case .success(let imageInfo):
                    // Access image via imageInfo.cgImage
                    break
                case .failure(let error):
                    break
            }
        }
    }
}

Thanks Dmytro, this will help a lot noobs like me. The thing is it does not compile.
Error messages are :
Result<ImageInfo, Error> -> Cannot specialize non-generic type 'Result'
completion(.success(transientImage.info))-> Type Result has no member success
completion(.failure(error)) -> Type Result has no member failure

Hey, what Swift version are you using? The Result type was added to the standard library with Swift 5.

I am on Swift 5 too

…

Le 12 janv. 2021 à 10:24, Dmytro Anokhin ***@***.***> a écrit : @dmytro-anokhin commented on this gist. Hey, what Swift version are you using? The Result type was added to the standard library with Swift 5. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <https://gist.github.com/51aaeecb03a4e8249d7783cc5c60cb3b#gistcomment-3591570>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADY54IMCOIOOZTD3VIUSEJTSZSVWTANCNFSM4V6A7SZQ>.

You probably have another Result type defined in the module. Try using Swift.Result instead.

You are right. I had a struct named Result and it interfered with your code. Thank for the help. Take care