无法将解析的数据保存到URLSession到Core Data上下文中（iOS 10，Swift 3）

Question

It is a part of a program for get weather information from some site. Into the program I'm using singleton for get Core Data context. AirportsICAO and AirportsData are Core Data subclasses. This function must parse the page and save all data to Core Data context, it work fine when parse data, but throwing the error when trying to save result to database. How to fix it? Any ideas.

2017-03-16 23:56:21.197036 Weather App[3603:81353] [Common] _BSMachError: port 700f; (os/kern) invalid capability (0x14) "Unable to insert COPY_SEND"

2017-03-16 23:56:21.197265 Weather App[3603:81353] [Common] _BSMachError: port 700f; (os/kern) invalid name (0xf) "Unable to deallocate send right"

    func getData(forICAO icaoCode: String) -> Bool {

    let config = URLSessionConfiguration.default
    let apiKey = "zzzzzzzzz-zzzz-zzzz-zzzz-zzzzzz"
    let url = URL(string: "https://somesite.com/current-conditions-list?api_key=" + apiKey + "&airports=" + icaoCode + "&states=&format=json")
    let session = URLSession(configuration: config)


    let task = session.dataTask(with: url!) { (data, responce, error) in



        if error == nil && data != nil {
            if let parsedDataArray = try? JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as! Array<Any> {
                if let parsedData = parsedDataArray[0] as? Dictionary<String, Any> {
                    guard let airport = parsedData["airport"] as? String else { return }
                    guard let airport_name = parsedData["airport_name"] as? String else { return }
                    let updatedByUser = Date()

                    // Core Data
                        let context = CoreDataManager.instance.persistentContainer.viewContext
                        let entityForAirportICAO = NSEntityDescription.entity(forEntityName: "AirportsData", in: context)
                        let airportICAO = AirportsICAO(entity: entityForAirportICAO!, insertInto: context)

                        airportICAO.airport = airport
                        airportICAO.airport_name = airport_name
                        airportICAO.updatedByUser = updatedByUser

                        try! context.save()
                }
            }
        }
    }

    task.resume()
    return true
}

Answer 1

The completion handler block for URLSession.dataTask(with:completionHandler:) is called on a background queue, but you're accessing the view context from that block. The view context should only be accessed from the main thread.

Instead, you should use a background task:

CoreDataManager.instance.persistentContainer.performBackgroundTask() { context in

    let entityForAirportICAO = NSEntityDescription.entity(forEntityName: "AirportsData", in: context)
    let airportICAO = AirportsICAO(entity: entityForAirportICAO!, insertInto: context)

    airportICAO.airport = airport
    airportICAO.airport_name = airport_name
    airportICAO.updatedByUser = updatedByUser

    try! context.save()
}