This my network Service layer I can’t understand where I made a mistake and why it doesn’t let me pull it out normally Result Help me figure out my head

And i have a trouble with network layer:

class NetworkService: Networking {
    func request(
        getURL: String,
        parameters: Dictionary<String, String>?,
        httpMethod: APIMethod,
        header: Dictionary<String, String>?,
        foregroundAPICall: Bool,
        debug: Bool,
        returnData: @escaping (_ result: Result<Data?, Error>) -> Void
    ) {
        
        guard let url = URL(string: getURL) else { return }
        var request = URLRequest(url: url)
        switch httpMethod {
        case .GET:
            request.httpMethod = httpMethod.description
            guard let headers = header else { return }
            for item in headers {
                request.addValue(item.key, forHTTPHeaderField: item.value)
            }
            break
        case .POST:
            request.httpMethod = httpMethod.description
            guard let headers = header else { return }
            for item in headers {
                request.addValue(item.key, forHTTPHeaderField: item.value)
            }
            request.httpBody = try? JSONSerialization.data(withJSONObject: parameters!, options: [])
            break
        }
        if httpMethod == .POST {
            let task = createDataTaskPost(
                with: request,
                complition: returnData
            )
            task.resume()  
        } 
    }
    private func createDataTaskPost(
        with request: URLRequest,
        complition: @escaping (_ result: Result<Data?, Error>) -> Void) -> URLSessionDataTask {
            return URLSession.shared.dataTask(
                with: request,
                completionHandler: { (data, response, error) in
                  
                    if let error = error {
                        complition(.failure(error))
                        return
                    }
                    guard let data = data else {  complition(.failure(ApiError.recieveNilBody))
                        return
                    }
                    complition(.success(data))
                })
        }
}

And here is my fetcher Here i need get the data from closure Result<T, Error>

It seems to me that I'm doing something wrong here, or I don't understand how I can get the result through closure

protocol DataFetcher {
    func fetchGenericJsonData<T: Codable>(
        urlString: String,
        parameters: Dictionary<String, String>?,
        httpMethod: APIMethod,
        foregroundAPICall: Bool,
        header: Dictionary<String, String>?,
        debug: Bool,
        returnData: @escaping (_ result: Result<[T?], Error>) throws -> Void
    )
}

public class NetworkDataFetcher: DataFetcher {
    var networking: Networking
    init(networking: Networking = NetworkService()) {
        self.networking = networking
    }
    func fetchGenericJsonData<T>(
        urlString: String,
        parameters: Dictionary<String, String>?,
        httpMethod: APIMethod,
        foregroundAPICall: Bool,
        header: Dictionary<String, String>?,
        debug: Bool,
        returnData: @escaping (_ result: Result<[T?], Error>) throws -> Void) {
            networking.request(
                getURL: urlString,
                parameters: parameters,
                httpMethod: httpMethod,
                header: header, foregroundAPICall: foregroundAPICall,
                debug: debug,
                returnData: { (data) in
                    **// Here i need get the data from closure Result<T, Error>**
                })
        }
}

CodePudding user response：

I figured out how to pull out the data now the problem is how to pull out an error

When I add this line try returnData(.failure(ApiError.failedParse)) to the catch method, it gives an error again

enter image description here

CodePudding user response：

The function fetchGenericJsonData expects you to do something, and then call the closure returnData with a result. Something like this:

func fetchGenericJsonData<T>(
    urlString: String,
    parameters: Dictionary<String, String>?,
    httpMethod: APIMethod,
    foregroundAPICall: Bool,
    header: Dictionary<String, String>?,
    debug: Bool,
    returnData: @escaping (_ result: Result<[T?], Error>) throws -> Void)
{
    // Do your network call. Then, if have a result, call:
    returnData(.success(value))
    // Or if you encountered an error:
    returnData(.failure(error))
}