Fetch data from Alamofire in background mode

Question

I need to update orders from my app while app is in background.

Ok, I am using OneSignal, I can get message on didReceiveRemoteNotification and inside it, I call Alamofire to check on my api what I need to update.

The problem is when the code get to the point: Alamofire.request(url).responseJSON {(response) in it doesnt go inside, just when I open the app I can get the result.

I would like it to get the new data on background and notify users after updating, so they can click on the notification to see whats is new.

I read that Alamofire runs on a background thread by default, but the network request goes on Main thread.

So, I tried: this and this, both don't work.

I tried URLSessionConfiguration but I got Error code -999 cancelled. So, I added sessionManager.session.finishTasksAndInvalidate() in the end of my response. The error stops, but the code still don't go inside Alamofire request.

Some of my code - didReceiveRemoteNotification on my AppDelegate:

func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any],
                     fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {

        if let custom = userInfo["custom"] as? NSDictionary {
            if let a = custom["a"] as? NSDictionary {
                if let update = a["update"] as? NSString {
                    if update.isEqual(to: "Pedido") {
                        let strdataPedido = PedidoDAO().getMostRecentDtPedido()

                        if self.defaults.getDownloadInicialPedido(){
                            if strdataPedido != "" {

                                //let task = self.beginBackgroundTask()
                                self.loadOrdersFromLastSyncByApi(strdataPedido)
                                //self.endBackgroundTask(task)
                            }
                        }
                    }
                }
            }
        }

loadOrdersFromLastSyncByApi function on my AppDelegate:

func loadOrdersFromLastSyncByApi(_ lastSync: String) {
        let parceiroId = defaults.getParceiroId()

        PedidoAPI().loadOrdersForLastSync(parceiroId, lastSync){ (dados) in
            if let dadosPedidoModel = dados as? [PedidoModel] {
                //do what needs to do to save new data
            }

PedidoAPI().loadOrdersForLastSync function:

func loadOrdersForLastSync(_ parceiroId: String, _ lastSync: String, _ onComplete: @escaping(Any?) -> Void) {

        let url = Test.basePath + "/api/orders/parceiro/\(parceiroId)/\(lastSync)"

        //let queue = DispatchQueue(label: "com.test.br", qos: .background, attributes: .concurrent)
        let task = self.beginBackgroundTask()

        let queue = DispatchQueue.global(qos: .background)
        queue.async {
        Alamofire.request(url).responseJSON {(response) in

            //This result its fired just when I open my app, I would like it to make everything on background
            switch (response.result) {
                //do what needs to send new data
            }
        self.endBackgroundTask(task)

Any help please?

score 1 · Answer 1 · answered Jun 08 '19 at 01:46

Thanks for your question. So to clarify, I understood your question as the following:

You want to update users when there has been a change in their orders while the app is in background.

Follow-up Question: Is there a reason you want to make the request from the client? Also, what data is coming in from OneSignal that you couldn't just handle on your server?

Answer: You should handle any requests to a third party (Alamofire) on the server and then use our API to send a notification to the user with new info from the request response. I think that would be the best approach.

Fetch data from Alamofire in background mode

1 Answers1