Im trying to build a network layer for my app so as I go through the project
I'm getting the error
"Cannot invoke 'decode' with an argument list of type '(Codable, from: Data)'" I think its happening because of error type or a mismatch Help me resolve this issue
enum Type:String {
case GET
case POST
case PUT
case DELETE
}
func networkRequest(MethodType:Type, url:String, codableType:Codable) {
guard let getUrl = URL(string: url) else {return}
if MethodType == Type.GET {
URLSession.shared.dataTask(with: getUrl) { (data, response, err) in
if let urlRes = response as? HTTPURLResponse{
if 200...300 ~= urlRes.statusCode {
guard let data = data else {return}
do {
let newData = try JSONDecoder().decode(codableType.self, from: data)
}
catch let jsonerr {
print("Error Occured :"+jsonerr.localizedDescription)
}
}
}
}.resume()
}
}
Generics can solve this problem.
First, introduce a generic type parameter:
func networkRequest<T: Decodable>(MethodType:Type, url:String)
^^^^^^^^^^^^^^
Now you can use T.self
for the type to decode:
try JSONDecoder().decode(T.self, from: data)
Also, you might consider adding a completion handler, otherwise the value you fetched will be lost:
func networkRequest<T: Decodable>(MethodType:Type, url:String, completionHandler: (T) -> Void)
Usage:
networkRequest(MethodType: .GET, url: ...) {
(myStuff: MyType) in
...
}