Swift 4 adding parameters to URLRequest completion handler - ios

Question

I'm trying to return some data from a URLRequest in Swift 4, and to do so I've added a completion handler to my function signature, just with a Bool for the time being. This is the function:
func getJson(completionHandler: #escaping (Bool) -> ()) {
let jsonUrlString = "https://api.nytimes.com/svc/topstories/v1/business.json?api-key=f4bf2ee721031a344b84b0449cfdb589:1:73741808"
guard let url = URL(string: jsonUrlString) else {return}
URLSession.shared.dataTask(with: url) { (data, response, err) in
guard let data = data, err == nil else {
print(err!)
return
}
do {
let response = try
JSONDecoder().decode(TopStoriesResponse.self, from: data)
print(response.results)
// Pass results into arrays (title, abstract, url, image)
completionHandler(true)
DispatchQueue.main.async {
self.tableView.reloadData()
}
} catch let jsonErr {
print("Error serializing JSON", jsonErr)
}
}.resume()
}
and I call it in viewDidLoad like so:
getJson { (success) in
print("Success")
}
Nothing is printing to the console so I'm wondering if I am using the completion handler correctly? But ultimately I'd like to switch out the Bool and instead pass a few values out of the request, back into arrays that I have in my view controller.
These are the structs I'm using to grab the pieces of JSON that i want:
struct TopStoriesResponse: Decodable {
let status: String
let results: [Story]
}
struct Story: Decodable {
let title: String
let abstract: String
let url: String
}
And I'm ultimately trying to fill these arrays in my view controller with the parsed JSON so I can arrange them in a table view:
var headlines = [String]()
var abstracts = [String]()
var urls = [URL]()
EDIT: Full code in case I'm going wrong somewhere else: https://pastebin.com/r402GKej

Answer 1

try creating the struct TopStoriesResponse and Story seperately from the ViewController and add the Networking struct to load data from the API
struct TopStoriesResponse: Decodable {
let status: String
let copyright: String
let num_results: Int
let results: [Story]
}
struct Story: Decodable {
let title: String
let abstract: String
let url: String
}
struct Networking {
static func getJson(completionHandler: #escaping (Bool) -> ()) {
let jsonUrlString = "https://api.nytimes.com/svc/topstories/v1/business.json?api-key=f4bf2ee721031a344b84b0449cfdb589:1:73741808"
guard let url = URL(string: jsonUrlString) else {
return
}
URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let data = data, error == nil else {
print(error!.localizedDescription)
return
}
do {
let response: TopStoriesResponse = try JSONDecoder().decode(TopStoriesResponse.self, from: data)
print(response.results.count)
completionHandler(true)
} catch {
print(error.localizedDescription)
completionHandler(false)
}
}.resume()
}
}
Now try calling Networking.getJson from the ViewController
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
loadData()
}
func loadData() {
Networking.getJson { (result) in
print(result)
}
}
}