Error in decoding: The data couldn't be read. Alamofire

Question

I was trying to parse JSON through JSONDecoder and using Alamofire to fetch the data. However, when I run the app, it shows that the data couldn't be read because of the incorrect format. I have tried many things but still did not work. Any help would be appreciated. Sources are below:

VC:

class SecondTaskVC: UIViewController {

var weatherModel = [WeatherModelDecodable]()

override func viewDidLoad() {
    let url = URL(string: "https://api.openweathermap.org/data/2.5/forecast?lat=42.874722&lon=74.612222&APPID=079587841f01c6b277a82c1c7788a6c3")

    Alamofire.request(url!).responseJSON { (response) in

        let result = response.data

        do{
            let decoder = JSONDecoder()
            self.weatherModel = try decoder.decode([WeatherModelDecodable].self, from: result!) // it shows this line as a problem

            for weather in self.weatherModel {
                print(weather.city.name)
            }
        }catch let error{
            print("error in decoding",error.localizedDescription)

        }

    }
     }
   }

Data Model:

struct WeatherModelDecodable: Decodable {
  let city: CityDecodable
}

struct CityDecodable: Decodable {
  let name: String
 }

Answer 1

Actually the response structure is different from what you are trying to do at this line,

self.weatherModel = try decoder.decode([WeatherModelDecodable].self, from: result!)

The response is not an array as you can see it in a json viewer by hitting this Url in any browser. You are expecting an array of json objects but its not. So if you decode it as a single object, it will decode properly as below,

let weatherModel = try decoder.decode(WeatherModelDecodable.self, from: result!)
print(weatherModel.city.name)

So, SecondTaskVC will look like this,

class SecondTaskVC: UIViewController {

    var weatherModel: WeatherModelDecodable?

    override func viewDidLoad() {
        let url = URL(string: "https://api.openweathermap.org/data/2.5/forecast?lat=42.874722&lon=74.612222&APPID=079587841f01c6b277a82c1c7788a6c3")

        Alamofire.request(url!).responseJSON { (response) in

            let result = response.data

            do{
                let decoder = JSONDecoder()
                self.weatherModel = try decoder.decode(WeatherModelDecodable.self, from: result!)
                print(self.weatherModel!.city.name)
            }catch let error{
                print("error in decoding",error.localizedDescription)

            }

          }
        }
 }

You should decode the respective objects with the same structure you are getting in the response.