Basic Alamofire RAC extension

gistfile1.swift

/**
 * Adapted from https://github.com/indragiek/AlamofireRACExtensions
 */
public func get<T>(url: String, f: (AnyObject -> Result<T, NSError>)) -> SignalProducer<T, NSError> {
    return SignalProducer { sink, disposable in
        let request = Alamofire.request(.GET, hostname + url)
            .responseJSON { (request, response, responseObject, error) in
                if let error = error {
                    sendError(sink, error)
                } else if let response = response {
                    if let responseObject: AnyObject = responseObject {
                        let res = f(responseObject)
                        switch res {
                        case let .Success(b):
                            println("successful web response \(b.value))")
                            sendNext(sink, b.value)
                            sendCompleted(sink)
                        case let .Failure(e):
                            sendError(sink, e.value)
                        }
                    } else {
                        assertionFailure("Received no response object for successful response \(response) from request \(request)")
                        sendCompleted(sink)
                    }
                } else {
                    fatalError("Invalid response -- no HTTP response or error")
                }
        }
        request.resume()
        disposable.addDisposable {
            request.cancel()
        }
    }
}