Code working in AppDelegate but not in any other class - ios

Question

I am using socket.io client for swift. When I declare and connect the socket and use its commands in AppDelegate, things work fine. But as soon as I move this stuff from AppDelegate to another class (making socket a global variable) and call the function of that class from AppDelegate, socket errors start to appear (the description of errors is really irrelevant to this topic. I had a discussion regarding that in Socket.io issues)
The question I wanna ask is this happening? I have used
deinit {
NSLog("CCNOTIFICATIONS RESOURCES GOT DE INITIALIZED")
}
in that file but this never gets called.
According to my knowledge, AppDelegate is a delegate which gets called when there is some change in app's state i-e its launches or goes to background/foreground. And also that it is not a good practice to mess huge amount of code in AppDelegate.
Apparently there is no difference in scope of both files then why is this happening?
Please correct me if I am wrong in my understanding.
How this error problem can be solved? Or least what other approach I can try to get to root of this problem?
Any help would be appreciated.
UPDATE:
Here is the code:
When I write it in AppDelegate:
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
public static var socket = SocketIOClient(socketURL: URL(string: “URL”)!, config: [.log(true), .compress])
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
AppDelegate.socket.connect()
AppDelegate.socket.on("connect") {data, ack in
print("Connected successfully")
}
AppDelegate.socket.on("book-adventure-provider") {data, ack in
print("BOOKING CAME")
print(data)
}
return true
}
When I write it in other file:
CCNotifications:
public class CCNotifications : INotifications
{
public var socket = SocketIOClient(socketURL: URL(string: “URL”)!, config: [.log(true), .compress, .forcePolling(true), .forceNew(true)])
public func sendBookingRequest(adventureId: String, success: #escaping () -> Void, error: #escaping CErrorCallback) {
if (ConnectionStatus.isConnected() == false)
{
let errorObj = CError()
errorObj.message = "No internet connection"
errorObj.code = ClientConstants.connectionErrorCode
error(errorObj)
}
else
{
let jwtToken = KeychainWrapper.standard.string(forKey: "jwtToken")
let data = ["adventure_id": adventureId, "jwt": jwtToken]
socket.emit("book-adventure", data)
socket.on("book-adventure-seeker") { data, ack in
print(data)
}
}
}
}
CuufyClient:
public class CuufyClient : IClient {
public var notifications: INotifications? = nil
public static var Notifications: INotifications? { get { return CuufyClient.client?.notifications}}
//region Actions
public static func Initialize(completion: ((_ error: CError?) -> Void)?) {
CuufyClient.client?.notifications = CCNotifications ()
completion? (nil)
}
//endregion
}
Finally calling it as:
CuufyClient.Notifications?.funcWhichIWannaCall.
Note:
Both ways work. But when I write code in CCNotifications and run it, at sometimes it starts giving socket error: Session id unknown and then connects itself again and again.
UPDATE 2:
A line before the socket error in the logs I have observed this error:
2017-12-15 15:45:34.133480+0500 TestTarget[5332:230404] TIC Read Status [1:0x60000017f440]: 1:57
Upon searching this error I got to know that in Xcode 9, this error shows that TCP connection has closed. When I opened this issue on socket.io branch the specialist said:
This library operates on a fairly high level above the underlying
networking. It relies on either URLSession or Starscream to tell it
when the connection is lost.
Can anyone help me regarding URLSession that why TCP is getting closed as I am fairly new to iOS.

Answer 1

First to say, your approach of keeping the AppDelegate thin is a good idea.
Regarding the deinit: This function will be called when the object ceases to exist. Since global variables will life "forever" - as long as they are assigned to a different object - they will be cleaned up only at program termination (not: background mode etc.) Therefore, you will never see the deinit call.
Your thoughts about the life cycle are correct, there shouldn't be a difference if you have done everything correctly - which I cannot judge here because you didn't show any code of how and when that global socket is created/initialized etc.
Regarding the updated question: Unfortunatly, I don't know the socket.io library. But having just a short look, your code differs slightly between the AppDelegate and the other version. It might be a timeing issue - just check (and maybe fix) a few things:
When do you call connect()?
You might want to first set up all the ...on()-Handlers before connecting or calling emit; otherwise the server might respond before everything has set up correctly
Check if you might set up the ...on()-Handlers only one, centrally, and not with every sendBookingRequest-call
What is jwtToken? Is it an API token for you application, or some kind of seesion token? When do you store the value, and why is it stored in the keychain? Might its value change during requests/responses?

Answer 2

You should not place socket event listener in sendBookingRequest method.
You just need to bind a socket event listener once.
socket.on("book-adventure-seeker") { data, ack in
print(data)
}
so, you can place it in on connect event.
AppDelegate.socket.on("connect") {data, ack in
print("Connected successfully")
}