Session was Invalidated -- Alamofire

Question

i have used the singleton pattern for networking call but one issues is faced can anyone help me to solved this issue the session was invalidated

Session was invalidated without error, so it was likely deinitialized unexpectedly. Be sure to retain a reference to your Session for the duration of your requests.

and my networking wrapper is

public static let shared = NetworkingClient()
    private var requests = [ApiRequest]()
    private var completedRequests = 0
    private var session: Session!
    func InvalidateSession () {
        if #available(iOS 9.0, *) {
            Alamofire.Session.default.session.getAllTasks { (tasks) in
                    tasks.forEach{ $0.cancel() }
                }
            } else {
            Alamofire.Session.default.session.getTasksWithCompletionHandler { (sessionDataTask, uploadData, downloadData) in
                sessionDataTask.forEach { $0.cancel() }
                uploadData.forEach { $0.cancel() }
                downloadData.forEach { $0.cancel() }
            }
        }
    }

This is my Api Call the secanrio is increase quantity then crash the alomofire i want to stop the send request multiple request i want to send request api only 1 time

func gasEstimation(chain_Id: Int, contractAddress: String, fromAddress: String, toAddress: String, tokenId: String, contractType: String, quantity: String) {
        let apiRequest = [ApiRequest(type: .get, path: "gasEstimation?chainId=\(chain_Id)&contractAddress=\(contractAddress)&from=\(fromAddress.trimmingCharacters(in: .whitespacesAndNewlines))&to=\(toAddress.trimmingCharacters(in: .whitespacesAndNewlines))&type=\(contractType)&quantity=\(quantity)&tokenId=\(tokenId)")]
        NetworkingClient.shared.performRequest(requests: apiRequest) { path, data, error in
            if data != nil {
                let json =  JSON(data!)
                let gasTokenModel = NftTransferModel(json: json)
                self.presenter?.onReceiveFee(estimationFee: gasTokenModel,error: nil)
            }else{
                let error = JSON(error!)
                self.presenter?.onReceiveFee(estimationFee: nil,error: error["message"].stringValue)
            }
        }
    }

Answer 1

There are a few issues here.

1. The use of Session! indicates you're operating on an optional value, which seems unnecessary. Also, if you're replacing this value, this is likely the cause of the invalidation error, as the Session that was replaced will invalidate when it's deinited.
2. You have private var session: Session!, yet you use Session.default to cancel all of your requests. This is incorrect, you need to cancel requests on your local session.
3. Manually cancelling all of the requests like you are is unnecessary and may break Alamofire's internal assumptions. Never interact with the URLSession instance directly. Instead, Session has a cancelAll() method you can use to do the same thing.
4. Alamofire doesn't support iOS 9, so that version condition check is unnecessary.
5. I suggest you transition to using Decodable for your JSON parsing, it's far simpler and Alamofire has built-in support for it.