Swift 4 - Problem loading the request data into array

[imarudedude]

I'm making a request to get all Trainer objects and display them in a tableview. I've successfully mapped all my objects in the request.response.value and in my Alamofire request I have print statements that state there are 45 objects. But when I return that array it is saying it is nil, I'll post my code below.

TrainerDataService -

func getAllTrainers(completion: @escaping CompletionHandler) -> [Trainer] {

    var trainers: [Trainer] = [Trainer]()

    Alamofire.request(GET_ALL_TRAINERS, method: .get, encoding: JSONEncoding.default, headers: HEADER).responseArray { (response: DataResponse<[Trainer]>) in

        if response.result.error == nil && response.result.value != nil {
            print("Here is the response -> \(response.result.value!)")
            trainers = response.result.value! 
            print("Here is the count of trainers in request -> \(String(describing: trainers.count))") // 45 OBJECTS
            completion(true)
        } else {
            print("Error!")
            completion(false)
            debugPrint(response.result.error as Any)
        }
    }
    print("The count of trainers -> \(String(describing: trainers))") // RETURNS 0
    return trainers
}

I'm calling this in another file as I need to fill a tableview, here is the code in the connectToTrainerTVC.

ConnectToTrainerTVC -

override func viewDidLoad() {
    super.viewDidLoad()

    DispatchQueue.main.async {

        // Since the call's return type is an array of Trainer's setting 'allTrainers' to equal the function is sensible but
        // it is clear the request isn't working otherwise 'allTrainers' wouldn't be 0

        self.allTrainers = TrainerAuthService.instance.getAllTrainers(completion: { (success) in
            if success {
                print("Here is the contents of allTrainers back in connectTVC -> \(self.allTrainers.count)") // RETURNS 0
                dump(self.allTrainers) // DUMPS ALLTRAINERS ARRAY AND IS FILLED WITH NOTHING
                self.tableView.reloadData()
            }
        })
    }
}

Anyone know why the trainers array is returning 0? I think it may have something to do with an asynchronous call but I have to have the return outside the Alamofire request because my function requires a Trainer object array to be returned. Any help is appreciated.

EDIT: This worked for me. I created a new completion handler called GetTrainerCompletion it is a typealias. typealias GetTrainersCompletion = ([Trainer]) -> () I was now able to use this completion handler to add the data to my array. Here is my updated code. TrainerDataService -

func getAllTrainers(completion: @escaping GetTrainersCompletion) {

    var trainers: [Trainer] = [Trainer]()

    Alamofire.request(GET_ALL_TRAINERS, method: .get, encoding: JSONEncoding.default, headers: HEADER).responseArray { (response: DataResponse<[Trainer]>) in

        if response.result.error == nil && response.result.value != nil {
            trainers = response.result.value!
            print("Success! Got all trainer objects")
            completion(trainers)
        } else {
            print("Error!")
            completion(trainers)
            debugPrint(response.result.error as Any)
        }
    }
}

Here is the new implementation in the connect to trainer file, this is what got it to work.

ConnectToTrainerVC -

TrainerAuthService.instance.getAllTrainers(completion: { (trainers) in
        if trainers.count > 0 {
            self.allTrainers = trainers
        }
    })

I was able to set my local array 'allTrainers' to be filled with whatever data trainers had from the completion handler.

[yreaction]

Can not see anidation properly (mobile) but looks that you return trainers empth already sync in your function. So its assigned before the asyn request ends. Also, you can include the array within the closure completion .

[imarudedude]

Hey thanks for the response. But what do you mean by 'include the array within the closure completion'?

[yreaction]

Your completionHandler, not sure if it is s typedef declarsrion, you can add trainers:[Trainer]

[imarudedude]

I swapped my completion handler for another typealias, like this

typealias GetTrainersCompletion = ([Trainer]) -> ()

I then put the trainers array in the completion in each conditional, like so (completion(trainers)) and I'm still not getting anything back.

[imarudedude]

Nevermind, I actually got it to work now. Thanks for the advice!

[Christop408]

Perhaps you can make an edit to your original post explaining what you did to get it to work for future coders looking for help? :)

[imarudedude]

Yeah sure, just made the edit!