Wsrtjtyk

I have a method which performs an HTTP request and retrieves data from a website, it's working as expected, I'm getting the data correctly. What I haven't been able to do is return the retrieved value when the method is called.

Here is the code...

func myFunction(zipCode: String)->String{

    var myData:String = ""



    let siteLink = "http://example.com/zip/" + zipCode

    let url = URL(string: siteLink)



    let task = URLSession.shared.dataTask(with: url!) { data, response, error in

        guard error == nil else {

            print(error!)

            return

        }

        guard let data = data else {

            print("Data is empty")

            return

        }

        let json = try! JSONSerialization.jsonObject(with: data, options: )

        guard let jsonArray = json as? [[String: String]] else {

            return

        }

        myData = jsonArray[0]["MyPropertyName"]!

        // Here, myData outputs, "Info for zip code 52484 from HTTP request"

    }



    task.resume()



    return myData

}

When I call myFunction I get and empty string...

myFunction(zipCode: "52484")// Outputs an empty string

What I was expecting to see is a return value of "Info for zip code 52484 from HTTP request" since the myData variable was modified inside the let task = before the return call. I tried returning inside the let task = but this cannot be done in Swift.

How can I return the retrieved value when the myFunction is called?

You need a completion as request is asynchronous

func myFunction(zipCode: String,completion:@escaping(_ str:String?) -> () ) {



    let siteLink = "http://example.com/zip/" + zipCode

    let url = URL(string: siteLink)



    let task = URLSession.shared.dataTask(with: url!) { data, response, error in

        guard error == nil else {

            print(error!)

            completion(nil)

            return

        }

        guard let data = data else {

            print("Data is empty")

            completion(nil)

            return

        }

        let json = try! JSONSerialization.jsonObject(with: data, options: )

        guard let jsonArray = json as? [[String: String]] else {

            completion(nil)

            return

        }

        let myData = jsonArray[0]["MyPropertyName"]!

        completion(myData) 

    } 

    task.resume() 

}

Call

myFunction(zipCode: "52484") { (str) in 

  if let st = str {

    print(st)

   }

}