JSONSession

/// if the response is 200, the server will send us an item
struct ItemProcessor: Processor {
    struct Item: Decodable {
        let name: String
    }

    let codes = [200]
    func process(_ item: Item, response: HTTPURLResponse, in session: Session) -> RepeatStatus {
        print("Received item \(item.name)")
        return .inherited
    }
}

/// if the response is 400, the server will send us an error
struct ErrorProcessor: Processor {
    struct Error: Decodable {
        let error: String
    }

    let codes = [400]
    func process(_ payload: Error, response: HTTPURLResponse, in session: Session) -> RepeatStatus {
        print("Something went wrong: \(payload.error)")
        return .inherited
    }
}

// make a session for the service we're targetting, supplying the authorization token
let session = Session(base: URL(string: "https://some.endpoint/v1/")!, token: "<api-token>")

// schedule polling of some REST resource
session.poll(target: Resource("some/rest/request"), processors: [ItemProcessor(), ErrorProcessor()], repeatingEvery: 1.0)

// the endpoint will be queried repeatedly by the session
// when an expected response comes back, the response will be decoded and one of our processor objects will be called to process it
RunLoop.main.run()