How to print error message while parsing in swift - ios

Question

this is json error structure:
{
"jsonrpc": "2.0",
"error": {
"code": "-32700",
"message": "Parse error",
"meaning": "Could not decode token: Error while decoding to JSON: Syntax error"
}
}
this is success response structure:
{
"jsonrpc": "2.0",
"result": {
"users": [
{
"id": 371,..... so on data
here am unable to print error > message in my code
code: here able to print json response result or error dictionary in case .success(_) print statement but how to print only error > meaning
how to print error's "Parse error" in below code, please guide me
class GeneralResponse<T: Codable>: Codable {
var result: T?
let error: ErrorClass?
}
struct ErrorClass: Codable {
let code, message, meaning: String?
}
struct RequestObject {
var params: [String: AnyObject]? = nil
var method: HTTPMethod
var path: String
var isTokenNeed: Bool = false
var vc: UIViewController?
}
class NetworkManager {
private let decoder: JSONDecoder
static let sharedInstance = NetworkManager()
public init(_ decoder: JSONDecoder = JSONDecoder()) {
self.decoder = decoder
}
public func serviceCall<T: Codable>(_ objectType: T.Type,
with request: RequestObject,
completion: #escaping (T?, Error?) -> Void) {
let paramsDict = ["jsonrpc" : "2.0", "params" : request.params ?? nil] as [String : Any?]
AF.request(request.path, method: request.method, parameters: paramsDict as [String : AnyObject], encoding: JSONEncoding.default, headers: "Accept": "application/json")
.responseJSON { response in
switch response.result {
case .success(_):
do {
print("only json respopnse \(response)")
let data = response.data
let responseData = try self.decoder.decode(T.self, from: data ?? Data())
completion(responseData, nil)
} catch {
completion(nil, error)
print("in catch \(error)")
}
case .failure(let AFError):
let error = AFError
print(error.localizedDescription)
print("failure error: \(error)")
}
}
}
}
o/p for error in above call with print("only json respopnse \(response)")
only json respopnse success({
error = {
code = "-32700";
meaning = "Token Signature could not be verified.";
message = "Parse error";
};
jsonrpc = "2.0";
})
EDIT 2: here success response not coming in viewcontroller
struct PostModel: Codable {
let jsonrpc: String?
let result: PostResult?
}
struct PostResult: Codable {
let users: [PostUser]?
}
struct PostUser: Codable {
let id: Int?
}
and calling like this in vc
var k12Data: PostModel?
let paramet = ["location": "", "country": "", "gender": "", "keyword": ""] as [String : AnyObject]
let request = RequestObject(params: paramet, method: .post, path: "https://phpwebdevelopmentserv/", isTokenNeed: true, vc: self)
NetworkManager.sharedInstance.serviceCall(PostModel.self, with: request) { (response, error) in
print("viewcontroller data \(response)")
}
o/p
viewcontroller data Optional(TestigAllInOne.PostModel(jsonrpc: nil, result: nil))

Answer 1

You didn´t show us your Postmodel so I am asuming it is of some type of GeneralResponse<T> class.
You should decode to your GeneralResponse class:
let responseData = try self.decoder.decode(GeneralResponse<T>.self, from: data)
now you can print your error if one exists:
print(responseData.error?.meaning ?? "no error")
and call your completion handler like this:
guard let result = responseData.result else{
// unknown error has occured
completion(nil, nil) // you probably need to create a custom error here
return
}
completion(result, nil)
the main essence is to not pass GeneralResponse as argument to your function but the result type you are expecting. So if for example your User type looks like this:
struct User: Codable{
var id: String
}
call it like this:
networkmanager.serviceCall([User].self, with: RequestObject(...)) { users, error in
// users is of type `[User]` here.
}