Is it a good practice to reload credentials before every request? - swift

Question

I'm working on an iOS app that works with a backend made in laravel, this api manage login and information exchange via JSON web tokens.
To prevent the user to access a web route with an expired token I check the user's credentials before every web call.
My question is, is it a good practice? Because when I started thinking about it the user is accessing twice the amount of times to my server.
For example this is the function to access they're information.
/// Get user's info form the database
///
/// - Parameter completed: Completition Block
func getInfo(completed: #escaping DownloadComplete){
let token = self.getToken()
print(self.getError())
if(token != nil && token != ""){
//Here is where I check credentials.
self.checkCredentials(completed: {
let url = "\(Base_URL)\(myInfo)\(self.getToken() ?? "")"
Alamofire.request(url, method: HTTPMethod.get).responseJSON { respone in
if let result = respone.result.value as? Dictionary<String, AnyObject>{
if let user = result["User"] as? Dictionary<String, AnyObject>{
var Info = Alumno()
if let id = user["id"] as? Int64!{
Info.id = id
}
...
self.userInfo = Info
completed()
}
}
}
})
}
}
The check credentials functions asks the server if the user's token is still valid and if it is it returns
{
"Status": "Success"
}

Answer 1

My answer assumes your server validates the token, and you are not relying on the app to validate the token.
With that assumption, I think it depends on what you can do if the token is expired.
If the only thing you can do is prompt the user to sign in again, then I would probably just make the web request and handle the 401 Not Authorized.
However, if you have the ability to silently refresh the user's token, you may want to preemptively refresh the token if is close to expiring.
In my application, before every web request the app checks if the user's access token will expire within the next 3 minutes, and if so, attempts to refresh it before making the request. If the refresh is successful, the web request is made with the new access token. If the refresh fails, the web request is not made and the app prompts the user to sign in instead. If for any reason the web request still fails after that with 401, the app prompts the user to sign in.

Answer 2

I would do it like once every time the user opens the app not every call.
Other options:
You could also give them a code that they enter that's good for so long.
You could have them sign in when they first download the app. Then they would always be logged in. Then when the token is expired a little popup would say "Something Something Something"