How to handle the response of all types of requests in one handler, but also uniquely handle every request with Alamofire and Moya

Question

In my app I use Moya and Alamofire (And also Moya/RxSwift and Moya-ObjectMapper ) libraries for all network requests and responses.

I would like to handle the response of all types of requests in one handler, but also uniquely handle every request.

For example for any request I can get the response "Not valid Version", I would like to avoid to check in every response if this error arrived.

Is there an elegant way to handle this use case with Moya ?

Answer 1

Apparently that is very simple, You just should create your own plugin. And add it to your Provider instance (You can add it in the init function)

For example:

struct NetworkErrorsPlugin: PluginType {

    /// Called immediately before a request is sent over the network (or stubbed).
    func willSendRequest(request: RequestType, target: TargetType) { }

    /// Called after a response has been received, but before the MoyaProvider has invoked its completion handler.
    func didReceiveResponse(result: Result<Moya.Response, Moya.Error>, target: TargetType) {

        let responseJSON: AnyObject
        if let response = result.value {
            do {
                responseJSON = try response.mapJSON()
                if let response = Mapper<GeneralServerResponse>().map(responseJSON) {
                    switch response.status {
                    case .Failure(let cause):
                        if cause == "Not valid Version" {
                            print("Version Error")
                        }
                    default:
                        break
                    }
                }
            } catch {
                print("Falure to prase json response")
            }
        } else {
            print("Network Error = \(result.error)")
        }
    }
}

Answer 2

I suggest to use generic parametrized method.

class DefaultNetworkPerformer {
    private var provider: RxMoyaProvider<GitHubApi> = RxMoyaProvider<GitHubApi>()


    func performRequest<T:Mappable>(_ request: GitHubApi) -> Observable<T> {
        return provider.request(request).mapObject(T.self)
    }
}

DefaultNetworkPerformer will handle all requests from you Moya TargetType . In my case it was GitHubApi . Example usage of this implementation is:

var networkPerformer = DefaultNetworkPerformer()
let observable: Observable<User> = networkPerformer.performRequest(GitHubApi.user(username: "testUser"))

here you 'inform' network performer that response will contain User object.

observable.subscribe {
    event in
    switch event {
    case .next(let user):
        //if mapping will succeed here you'll get an Mapped Object. In my case it was User that conforms to Mappable protocol
        break
    case .error(let error):
        //here you'll get MoyaError if something went wrong
        break
    case .completed:
        break
    }
}