Execute GET request synchronously - ios

Question

I have a function that sends a GET request to an API and I need to wait for the response before I can continue with the rest of my code.
I have tried various different threads but haven't got it to work. I've been trying to solve this by myself but I am quite confused by threads and so fourth.
These are my functions:
func checkDomains() {
let endings = [".com"]
for ending in endings {
let domainName = names[randomNameIndx] + ending
let urlString = "https://domainr.p.mashape.com/v2/status?mashape-key={my-key}" + domainName
let url = URL(string: urlString)
var request = URLRequest(url: url!)
request.setValue("{my-key}", forHTTPHeaderField: "X-Mashape-Key")
request.setValue("application/json", forHTTPHeaderField: "Accept")
request.httpMethod = "GET"
var ourBool = false
DispatchQueue.main.sync {
let task = URLSession.shared.dataTask(with: request, completionHandler: { (data, response, er) in
do {
print("hey")
if let json = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? NSDictionary {
ourBool = String(describing: json).contains("inactive")
if ourBool {
self.domainStatuses.append("available")
} else {
self.domainStatuses.append("taken")
}
}
} catch {
}
})
task.resume()
}
}
}
#objc func btnTapped(sender: UIButton) {
self.prepareForNewName()
sender.shake(direction: "horizontal", swings: 1)
self.checkDomains() // This needs to finish before calling the next functions
self.setupForNewName()
self.animateForNewName()
}

Answer 1

My suggestion is in adding callback param into your async function. Example below:
func checkDomains(_ onResult: #escaping (Error?) -> Void)
Then you can call onResult inside your function in places where server return success result or error.
func checkDomains(_ onResult: #escaping (Error?) -> Void) {
...
let task = URLSession.shared.dataTask ... {
do {
//Parse response
DispatchQueue.main.async { onResult(nil) }
} catch {
DispatchQueue.main.async { onResult(error) }
}
...
}
}
The last thing you need pass callback param in place where you calling checkDomains function
#objc func btnTapped(sender: UIButton) {
self.prepareForNewName()
sender.shake(direction: "horizontal", swings: 1)
self.checkDomains { [unowned self] error in
if let error = error {
// handle error
return
}
self.setupForNewName()
self.animateForNewName()
}
}

Answer 2

Thank you for your answers. I just came home and realized there is a simpler way of doing this.
let task = URLSession.shared.dataTask(with: request, completionHandler: { (data, response, error) in
do {
...
if response != nil {
DispatchQueue.main.async {
self.setupForNewName()
self.animateForNewName()
}
}
}
} catch {
print(error)
}
})
task.resume()
Of course this is dependent on the response of the API but I am confident enough the API will always respond.

Answer 3

Lately it is a good practice to do network call asynchronously. There some technics to make code simpler, like https://cocoapods.org/pods/ResultPromises
TBC...