Swift 3 - Send make synchronous http request
There is always a way to use the asynchronous pattern.
To make the function asynchronous add a completion block
func completeLoadAction(urlString:String, completion: (Int) -> ()) {
let url = URL(string:urlString.trimmingCharacters(in: .whitespaces))
let request = URLRequest(url: url!)
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else { // check for fundamental networking error
print("error=\(error)")
DispatchQueue.main.async {
let ac = UIAlertController(title: "Unable to complete", message: "The load has been added to the completion queue. This will be processed once there is a connection.", preferredStyle: .alert)
ac.addAction(UIAlertAction(title: "OK", style: .default))
self.present(ac, animated: true)
}
completion(0) // or return an error code
return
}
let httpStatus = response as? HTTPURLResponse
var httpStatusCode:Int = (httpStatus?.statusCode)!
let responseString = String(data: data, encoding: .utf8)
print("responseString = \(responseString)")
DispatchQueue.main.async {
let ac = UIAlertController(title: "Completed Successfully", message: "The "+coldel+" has been completed successfully", preferredStyle: .alert)
ac.addAction(UIAlertAction(title:"Continue", style: .default, handler: { action in self.performSegue(withIdentifier: "segueConfirmedLoad", sender: self) }))
self.present(ac, animated: true)
}
completion(httpStatusCode)
}
task.resume()
}
and call it thusly
completeLoadAction(urlString: "www.something.com") { code in
print(code)
}
To make it synchronous and wait you can use semaphores such as below
struct Login {
static func execute() -> Bool {
let request = NSURLRequest....
var success = false
let semaphore = DispatchSemaphore(value: 0)
let task = URLSession.shared.dataTask(with: request, completionHandler: { _, response, error in
if let error = error {
print("Error while trying to re-authenticate the user: \(error)")
} else if let response = response as? HTTPURLResponse,
300..<600 ~= response.statusCode {
print("Error while trying to re-authenticate the user, statusCode: \(response.statusCode)")
} else {
success = true
}
semaphore.signal()
})
task.resume()
_ = semaphore.wait(timeout: DispatchTime.distantFuture)
return success
}
}