Multithreaded requests in Swift

multithreading_request.swift

import Foundation
import Dispatch


func getRequestTask(url: String, dispatchGroup: DispatchGroup) {
  dispatchGroup.enter()
  
  let request = URLRequest(url: URL(string: url)!)
  let task = URLSession(configuration: URLSessionConfiguration.default).dataTask(
    with: request, 
    completionHandler: {
      (data, response, error) in
      if let data = data {
        if let dataAsString = String(data: data, encoding: .utf8) {
          print(dataAsString)
          dispatchGroup.leave()
          return
        }
      }
      print("Something terrible has happened!")
      dispatchGroup.leave()
    }
  )
    
  task.resume()
}

let requestDispatchGroup = DispatchGroup()
for url in [
  "https://jsonplaceholder.typicode.com/posts",
  "https://jsonplaceholder.typicode.com/comments",
  "https://jsonplaceholder.typicode.com/albums"
] {
  getRequestTask(url: url, dispatchGroup: requestDispatchGroup)
}
requestDispatchGroup.wait()