Finish all asynchronous requests before loading data?

Question

I have run into an issue where I have multiple asynchronous requests occuring which grab images and information from the Facebook API and my Firebase database. I want to per

Answer 1

The two requests are executing at the same time, so there is no attendees to get pictures from when the second request executes, if the getAttendees completion closure is going to be called multiple times then you can do something like this:

let group = dispatch_group_create()

for key in keys {
   dispatch_group_enter(group)
   self.getAttendee(key as String, completion:{ (result, attendee) in
      if(result == true){
         attendees.addEntriesFromDictionary(attendee)
         self.getAttendeesPictures(attendee, completion: { (result, image) in
           if result == true {
              attendeesImages.append(image!)
           }
           dispatch_group_leave(group)
         })
      } else {
         dispatch_group_leave(group)
      }            
   })
}

dispatch_group_notify(group, dispatch_get_main_queue()) {}

If the result of the first request is the complete set of attendees you don't even need to use GCD, just call getAttendeesPictures inside the completion closure.

This code doesn't exactly uses the same variables and methods of the original code, it only gives the idea.

Hope it helps!