Comment extraire des informations d'API à l'aide des structures et décodable à Swift 4-5?

Ici, je partage 3 options possibles (en utilisant "si laisse", en utilisant "Guard let" et en utilisant "codable").

Si la méthode de la lettre suivante: p> xxx pré>

Méthode de protection: p> xxx pré>

méthode codable: p>

//MARK: - Structs to get the information from the openWeather API
struct OWElements:Codable {
var coord:CoordinatesDetails
var weather:[WeatherDetails]
var main:MainDetails
var wind:WindDetails
var sys:SysDetails
var name:String
}

struct CoordinatesDetails:Codable {
var lon:Float
var lat:Float
}

struct WeatherDetails:Codable {
var id:Int
var main:String
var description:String
var icon:String
}

struct MainDetails:Codable {
var temp:Float
var pressure:Float
var humidity:Float
var temp_min:Float
var temp_max:Float
}

struct WindDetails:Codable {
var speed:Float
var deg:Int
}

struct SysDetails:Codable {
var type:Int
var id:Int
var message:Float
var country:String
var sunrise:Int
var sunset:Int
}

//MARK: - Structs to get the information from the NASA API
struct NASAElements:Codable {
var features:[FeaturesDetails]
var parameterInformation:ParameterInformationDetails
}

struct FeaturesDetails:Codable {
var geometry:GeometryDetails
var properties:PropertiesDetails
}

struct GeometryDetails:Codable {
var coordinates:[Double]
}

struct PropertiesDetails:Codable {
var parameter:ParameterDetails
}

struct ParameterDetails:Codable {
var ALLSKY_SFC_SW_DWN:[String:Double]
var DIFF:[String:Double]
var DNR:[String:Double]
}

struct ParameterInformationDetails:Codable {
var ALLSKY_SFC_SW_DWN:ALLSKY_SFC_SW_DWNDetails
var DIFF:DIFFDetails
var DNR:DNRDetails
}

struct ALLSKY_SFC_SW_DWNDetails:Codable {
var longname:String
var units:String
}

struct DIFFDetails:Codable {
var longname:String
var units:String
}

struct DNRDetails:Codable {
var longname:String
var units:String
}

// MARK: - Class ViewController
class ViewController: UIViewController {

// MARK: - Variables and constants
var DNI = [Double](repeating: 0.0, count: 12)
var DHI = [Double](repeating: 0.0, count: 12)
var GHI = [Double](repeating: 0.0, count: 12)

// MARK: - Method viewDidLoad()
override func viewDidLoad() {
    super.viewDidLoad()

    // MARK: Open Weather API
    guard let urlJSONOpenWeather = URL(string: "http://api.openweathermap.org/data/2.5/weather?lat=51.9946&lon=4.378799&appid=get_api_id_openweather") else {

            print("There was an error on retrieving the Open Weather JSON url.")
            return

    }

    let openWeatherTask = URLSession.shared.dataTask(with: urlJSONOpenWeather) { (data, response, error) in

        if error == nil{

            guard let urlOpenWeatherData = data else{

                print("Error in the guard let urlOpenWeatherData")
                return

            }

            do {

                let openWeatherElements = try JSONDecoder().decode(OWElements.self, from: urlOpenWeatherData)
                print("This is the openWeather Elements:\n \(openWeatherElements)")

                // MARK: - Getting the coordinates (latitude and longitude)
                let openWeatherLatitude = openWeatherElements.coord.lat
                let openWeatherLongitude = openWeatherElements.coord.lon
                print("OpenWeather Latitude:\n \(openWeatherLatitude)º")
                print("OpenWeather Longitude:\n \(openWeatherLongitude)º")
                print("-----------------")

                // MARK: - Getting the weather description from an array of dictionary.
                let openWeatherWeatherArray = openWeatherElements.weather
                print("OpenWeather Weather Array:\n \(openWeatherWeatherArray)")

                guard let weather = openWeatherWeatherArray.first else {

                    print("There was an error on retrieving the elements of the 'weather' array.)")
                    return

                }

                print("These are the weatherArray elements: ", weather)
                print("ID: \(weather.id)")
                print("Main: \(weather.main)")
                print("Description: \(weather.description)")
                print("Icon: \(weather.icon)")
                print("-----------------")

                // MARK: - Getting the "main" elements
                let main = openWeatherElements.main
                print("This is main:\n \(main)")
                print("Temperature in Kelvin: \(main.temp)K")
                print("Pressure: \(main.pressure) hPa")
                print("Humidity: \(main.humidity)")

                let tempInCelsius = main.temp - 273.15
                print("Temperature in Celsius: \(String(format:"%.2f", tempInCelsius))ºC")

                let maxTempCelsius = main.temp_max - 273.15
                print("Max temperature in Kelvin: \(main.temp_max)K")
                print("Max temperature in Celsius: \(String(format:"%.2f", maxTempCelsius))ºC")

                let minTempCelsius = main.temp_min - 273.15
                print("Min temperature in Kelvin: \(main.temp_min)K")
                print("Min temperature in Celsius: \(String(format:"%.2f", minTempCelsius))ºC")
                print("-----------------")

                let windDetails = openWeatherElements.wind
                print("Wind speed: \(windDetails.speed)m/s")
                print("Wind direction: \(windDetails.deg)º")
                print("-----------------")

                let sysDetails = openWeatherElements.sys
                print("Type: \(sysDetails.type)")
                print("ID: \(sysDetails.id)")
                print("Message: \(sysDetails.message)")
                print("Country: \(sysDetails.country)")
                print("Sunrise: \(sysDetails.sunrise)")
                print("Sunset: \(sysDetails.sunset)")

                // First, we create a format of time for the sunrise and sunset
                let formatter = DateFormatter()
                formatter.dateStyle = .none
                formatter.dateStyle = .medium
                formatter.dateFormat = "HH:mm:ss"

                // Second, determine sunrise date and get sunrise time
                let sunriseValue = sysDetails.sunrise
                print("Sunrise Value: \(sunriseValue)")

                let sunriseDate = Date(timeIntervalSince1970: Double(sunriseValue))
                print("Sunrise date: \(sunriseDate)")

                let sunsetValue = sysDetails.sunset
                let sunsetDate = Date(timeIntervalSince1970: Double(sunsetValue))
                print("Sunset date: \(sunsetDate)")

                // Finally, determine sunset date and sunset time
                let sunrise = formatter.string(from: sunriseDate)
                let sunset = formatter.string(from: sunsetDate)
                print("Sunrise: \(sunrise)")
                print("Sunset: \(sunset)")
                print("-----------------")

                print("Region: \(openWeatherElements.name)")
                print("-----------------")
            }catch{

                print("Open Weather JSON Processing failed: \(error.localizedDescription)")

            }

        }

    }

    openWeatherTask.resume()

    //MARK: - NASA API
    guard let urlJSONNASA = URL(string: "https://power.larc.nasa.gov/cgi-bin/v1/DataAccess.py?request=execute&identifier=SinglePoint&parameters=DNR,DIFF,ALLSKY_SFC_SW_DWN&userCommunity=SSE&tempAverage=CLIMATOLOGY&outputList=JSON&lat=51.994693&lon=4.378553&user=anonymous") else{

        print("Could not retrieve the URL of NASA")
        return

    }

    let nasaTask = URLSession.shared.dataTask(with: urlJSONNASA) { (data, response, error) in

        if error == nil {

            guard let nasaData = data else{

                print("Error in the guard let nasaData")
                return

            }

            do{

                let nasaElements = try JSONDecoder().decode(NASAElements.self, from: nasaData)
                print("These are the NASA elements:\n \(nasaElements)")
                print("-----------------")

                let featuresArray = nasaElements.features
                print("Features as Array:\n \(featuresArray)")

                guard let features = featuresArray.first else{
                    print("There was an error on retrieving the elements of the 'features' array in the NASA API.)")
                    return
                }

                print("Features: \(features)")

                let geometry = features.geometry
                print("Geometry: \(geometry)")

                let NASALatitude = geometry.coordinates[1]
                let NASALongitude = geometry.coordinates[0]
                print("NASA Latitude: \(NASALatitude)º")
                print("NASA Longitude: \(NASALongitude)º")
                print("-----------------")

                let properties = features.properties
                print("Properties:\n \(properties)")
                print("-----------------")

                let parameter = properties.parameter
                print("Parameters:\n \(parameter)")
                print("-----------------")

                let ghi_raw = parameter.ALLSKY_SFC_SW_DWN
                let dni_raw = parameter.DNR
                let dhi_raw = parameter.DIFF

                print("GHI raw: \(dni_raw)")
                print("DNI raw: \(dni_raw)")
                print("DHI raw: \(dhi_raw)")

                // Put an order on each irradiance
                for index in 1...12{

                    self.DNI[index - 1] = (dni_raw[String(index)])!
                    self.DHI[index - 1] = (dhi_raw[String(index)])!
                    self.GHI[index - 1] = (ghi_raw[String(index)])!

                }

                print("GHI ordered: ", self.GHI)
                print("DNI ordered: ", self.DNI)
                print("DHI ordered: ", self.DHI)
                print("---------------------")

                let parameterInformation = nasaElements.parameterInformation
                print("Parameter Information:\n \(parameterInformation)")

                let ghiInfo = parameterInformation.ALLSKY_SFC_SW_DWN
                let dniInfo = parameterInformation.DNR
                let dhiInfo = parameterInformation.DIFF

                print("GHI Info: \(ghiInfo)")
                print("DNI Info: \(dniInfo)")
                print("DHI Info: \(dhiInfo)\n")

                print("GHI name: \(ghiInfo.longname)")
                print("GHI units: \(ghiInfo.units)\n")
                print("DNI name: \(dniInfo.longname)")
                print("DNI units: \(dniInfo.units)\n")
                print("DHI name: \(dhiInfo.longname)")
                print("DHI units: \(dhiInfo.units)\n")
                print("---------------------")

            } catch {

                print("NASA JSON Processing failed: \(error.localizedDescription)")

            }

        }

    }

    nasaTask.resume()

}

}