I am using GCDAsyncUdpSocket for communication between my app and some smart-home hardware, and I have a problem with stopping a certain function. Logic goes something like this:
- Send a command
- If you didn't receive feedback from the hardware, it'll try to send it a few more times
- When app receives feedback, notification DidReceiveDataForRepeatSendingHandler is posted (along with device information in userInfo)
For example, let's say I have a curtain that can react on 3 commands: Open, Close and Stop... and that curtain is currently closed. I press Open (and don't receive feedback), and during the process I change my mind, so I press Stop. Now the app will send both commands simultaneously.
So without further ado, here's the code:
class RepeatSendingHandler: NSObject {
var byteArray: [UInt8]!
var gateway: Gateway!
var repeatCounter:Int = 1
var device:Device!
var appDel:AppDelegate!
var error:NSError? = nil
var sameDeviceKey: [NSManagedObjectID: NSNumber] = [:]
var didGetResponse:Bool = false
var didGetResponseTimer:Foundation.Timer!
//
// ================== Sending command for changing value of device ====================
//
init(byteArray:[UInt8], gateway: Gateway, device:Device, oldValue:Int) {
super.init()
appDel = UIApplication.shared.delegate as! AppDelegate
self.byteArray = byteArray
self.gateway = gateway
self.device = device
NotificationCenter.default.addObserver(self, selector: #selector(RepeatSendingHandler.didGetResponseNotification(_:)), name: NSNotification.Name(rawValue: NotificationKey.DidReceiveDataForRepeatSendingHandler), object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(sameDevice(_:)), name: NSNotification.Name(rawValue: NotificationKey.SameDeviceDifferentCommand), object: nil)
sendCommand()
}
func updateRunnableList(deviceID: NSManagedObjectID) {
RunnableList.sharedInstance.removeDeviceFromRunnableList(device: deviceID)
}
// Did get response from gateway
func didGetResponseNotification (_ notification:Notification) {
if let info = (notification as NSNotification).userInfo! as? [String:Device] {
if let deviceInfo = info["deviceDidReceiveSignalFromGateway"] {
if device.objectID == deviceInfo.objectID {
didGetResponse = true
didGetResponseTimer = nil
NotificationCenter.default.removeObserver(self, name: NSNotification.Name(rawValue: NotificationKey.DidReceiveDataForRepeatSendingHandler), object: nil)
}
}
}
}
func sameDevice(_ notification: Notification) {
print("NOTIFICATION RECEIVED for device with ID: ", self.device.objectID, "\n")
if let info = notification.userInfo as? [NSManagedObjectID: NSNumber] {
sameDeviceKey = info
}
}
func sendCommand () {
if sameDeviceKey != [device.objectID: device.currentValue] { print("keys have DIFFERENT values") } else { print("keys have SAME values") }
if sameDeviceKey != [device.objectID: device.currentValue] {
if !didGetResponse {
if repeatCounter < 4 {
print("Sending command. Repeat counter: ", repeatCounter)
SendingHandler.sendCommand(byteArray: byteArray, gateway: gateway)
didGetResponseTimer = Foundation.Timer.scheduledTimer(timeInterval: 2, target: self, selector: #selector(RepeatSendingHandler.sendCommand), userInfo: nil, repeats: false)
repeatCounter += 1
} else {
didGetResponseTimer = nil
updateRunnableList(deviceID: device.objectID)
CoreDataController.shahredInstance.saveChanges()
NotificationCenter.default.removeObserver(self, name: NSNotification.Name(rawValue: NotificationKey.DidReceiveDataForRepeatSendingHandler), object: nil)
NotificationCenter.default.post(name: Notification.Name(rawValue: NotificationKey.RefreshDevice), object: self)
}
}else{
didGetResponseTimer = nil
updateRunnableList(deviceID: device.objectID)
CoreDataController.shahredInstance.saveChanges()
NotificationCenter.default.removeObserver(self, name: NSNotification.Name(rawValue: NotificationKey.DidReceiveDataForRepeatSendingHandler), object: nil)
NotificationCenter.default.post(name: Notification.Name(rawValue: NotificationKey.RefreshDevice), object: self)
}
} else {
print("Command canceled")
didGetResponseTimer = nil
return
}
}
On the ViewController where I keep my devices, I call this like:
func openCurtain(_ gestureRecognizer:UITapGestureRecognizer){
let tag = gestureRecognizer.view!.tag
let address = [UInt8(Int(devices[tag].gateway.addressOne)),UInt8(Int(devices[tag].gateway.addressTwo)),UInt8(Int(devices[tag].address))]
if devices[tag].controlType == ControlType.Curtain {
let setDeviceValue:UInt8 = 0xFF
let deviceCurrentValue = Int(devices[tag].currentValue)
devices[tag].currentValue = 0xFF // We need to set this to 255 because we will always display Channel1 and 2 in devices. Not 3 or 4. And this channel needs to be ON for image to be displayed properly
let deviceGroupId = devices[tag].curtainGroupID.intValue
CoreDataController.shahredInstance.saveChanges()
DispatchQueue.main.async(execute: {
RunnableList.sharedInstance.checkForSameDevice(device: self.devices[tag].objectID, newCommand: NSNumber(value: setDeviceValue))
_ = RepeatSendingHandler(byteArray: OutgoingHandler.setCurtainStatus(address, value: setDeviceValue, groupId: UInt8(deviceGroupId)), gateway: self.devices[tag].gateway, device: self.devices[tag], oldValue: deviceCurrentValue)
})
}
}
What I did was I made a separate class where I have a dictionary that has Device's ManagedObjectID as a key, and the command we are sending is it's value. So whenever we are sending a command for a device that's already on the list, I post a notification SameDeviceDifferentCommand with userInfo containing device's ManagedObjectID and the old command. I use it on RepeatSendingHandler to populate sameDeviceKey dictionary. That's how I tried to distinguish which function should be stopped.
public class RunnableList {
open static let sharedInstance = RunnableList()
var runnableList: [NSManagedObjectID: NSNumber] = [:]
func checkForSameDevice(device: NSManagedObjectID, newCommand: NSNumber) {
if runnableList[device] != nil && runnableList[device] != newCommand {
let oldDataToSend = [device: runnableList[device]!]
NotificationCenter.default.post(name: Notification.Name(rawValue: NotificationKey.SameDeviceDifferentCommand), object: self, userInfo: oldDataToSend)
print("Notification sent for device with ID: ", device, "\n")
}
runnableList[device] = newCommand
print("Device with ID: ", device, "received a new command", newCommand, "\n")
}
func removeDeviceFromRunnableList(device: NSManagedObjectID) {
runnableList.removeValue(forKey: device)
print("Removed from list device with ID: ", device)
}
}
However, sometimes it does it's job as it should, and sometimes it doesn't. Using a bunch of prints I tried to see in which order everything happens, and it seems that sometimes even though sameDeviceKey gets it's value from the notification - it looks like it uses old (nil) value until repeatCounter maxes out. I do not understand why.
Could anyone explain what is happening, and/or advise a better solution than the one I provided?
(There is a bit of additional code which I removed as it's irrelevant to logic/question). Please bear in mind that I am a junior and that I'm relatively new to this.
