LIH LIH - 25 days ago 12
Swift Question

How to check Alamofire request has completed

I am developing an iPad application using Swift. For http requests I use Alamofire library. So far I have managed to pull some data from an API. But the problem is since it is an asynchronous call I don't know how to check whether the request has completed. Any help would be appreciated.

This is the code I have implemented so far

Client class

func getUsers(completionHandler: ([User]?, NSError?) -> ()) -> (){

var users: [User] = []
let parameters = [
"ID": "123",
"apikey": "1234",
]

Alamofire.request(.GET, "API_URL", parameters: parameters).responseJSON() {
(_, _, JSON, error) in
let items = (JSON!.valueForKey("Users") as! [NSDictionary])
for item in items {
var user: User = User()
user.userId = item.valueForKey("ID")! as? String
user.userName = item.valueForKey("Name")! as? String
user.group = item.valueForKey("Group")! as? String
users.append(user)
}
completionHandler(users, error)
}

}


Main class

func getUsers(){
FacilityClient().getUsers() { (users, error) -> Void in
if users != nil {
self.users = users!
} else{
println("error - \(error)")
}
}
tableUsers.reloadData()
}


Thank you.

Answer

The closure part of the Alamofire request is called, when the request has completed. I've used your code and commented the line where the request hast finished:

Alamofire.request(.GET, "API_URL", parameters: parameters).responseJSON() {
        (_, _, JSON, error) in
      //
      // The request has finished here. Check if error != nil before doing anything else here.
      //            
        let items = (JSON!.valueForKey("Users") as! [NSDictionary])
        for item in items {
            var user: User = User()
            user.userId = item.valueForKey("ID")! as? String
            user.userName = item.valueForKey("Name")! as? String
            user.group = item.valueForKey("Group")! as? String
            users.append(user)
        }
      //
      // After creating the user array we will call the completionHandler, which probably reports back to a ViewController instance
      //
        completionHandler(users, error)
    }