Swift - URLSession

Links

Swift (Programmiersprache)

Einführung

Mit URLSession kannst du Anfragen an einen Webserver generieren und Antworten verarbeiten.

Schritte

• Create a URL
• Create a URLSession (kind of Browser Object)
• Give URLSession a Task (give the browser a url to fetch)
• Start the task

Beispiel

struct WeatherManager{
    
    let weatherURL = "https://api.openweathermap.org/data/2.5/weather?units=metric&appid=63981dbcfa548021dd77394d24f34674"
    
    func fetchWeather(cityName: String){
        let urlString = "\(weatherURL)&q=\(cityName)"
        performRequest(urlString: urlString)
    }
    
    func performRequest(urlString: String){
        // 1. create URL
        if let url = URL(string: urlString) {
            // 2. create URLSession
            let session = URLSession(configuration: .default)
            // 3. give session a task
            let task = session.dataTask(with: url, completionHandler: handle(data:response:error:))
            // 4. start the task
            task.resume()
        }
    }
    
    func handle(data: Data?, response: URLResponse?, error: Error?){
        if error != nil {
            print(error!)
            return
        }
        if let safeData = data {
            let dataString = String(data: safeData, encoding: .utf8)
            print(dataString!)
        }
    }
}

Oder besser mit Closure statt separater Funktion:

struct WeatherManager{
    
    let weatherURL = "https://api.openweathermap.org/data/2.5/weather?units=metric&appid=63981dbcfa548021dd77394d24f34674"
    
    func fetchWeather(cityName: String){
        let urlString = "\(weatherURL)&q=\(cityName)"
        performRequest(urlString: urlString)
    }
    
    func performRequest(urlString: String){
        // 1. create URL
        if let url = URL(string: urlString) {
            // 2. create URLSession
            let session = URLSession(configuration: .default)
            // 3. give session a task
            let task = session.dataTask(with: url) { data, response, error in
                if error != nil {
                    print(error!)
                    return
                }
                if let safeData = data {
                    let dataString = String(data: safeData, encoding: .utf8)
                    print(dataString!)
                }
            }
            // 4. start the task
            task.resume()
        }
    }
    
    func handle(data: Data?, response: URLResponse?, error: Error?){
        if error != nil {
            print(error!)
            return
        }
        if let safeData = data {
            let dataString = String(data: safeData, encoding: .utf8)
            print(dataString!)
        }
    }
}