how to pass output of HTTP request Task to variable in Swift - swift

Question

In Chrome browser, I input this address
https://jsonplaceholder.typicode.com/todos/1
Then I see output on Chrome window:
{
"userId": 1,
"id": 1,
"title": "delectus aut autem",
"completed": false
}
Now my question is that, can i do this in Swift?
Accessing an http address then get the output?
Now on this webpage, i find the below code.
import SwiftUI
// Create URL
let url = URL(string: "https://jsonplaceholder.typicode.com/todos/1")
guard let requestUrl = url else { fatalError() }
// Create URL Request
var request = URLRequest(url: requestUrl)
// Specify HTTP Method to use
request.httpMethod = "GET"
// Send HTTP Request
let task = URLSession.shared.dataTask(with: request) { (data, response, error) in
// Check if Error took place
if let error = error {
print("Error took place \(error)")
return
}
// Read HTTP Response Status code
if let response = response as? HTTPURLResponse {
print("Response HTTP Status code: \(response.statusCode)")
}
// Convert HTTP Response Data to a simple String
if let data = data, let dataString = String(data: data, encoding: .utf8) {
print("Response data string:\n \(dataString)")
}
}
task.resume()
I run this code in Playground in XCode. As it says on the webpage I got the right output:
Response data string:
{
"userId": 1,
"id": 1,
"title": "delectus aut autem",
"completed": false
}
But it prints on the console of XCode. I cannot find a way to pass this output to a variable. So I cannot go further.
I tried add lines like:
return dataString
all got error.
Or put it in a Func(), then call the function, also got error.
I am not a programmer and very new to Swift, hope people here can help.

Answer 1

You need to decode from JSON and store the result in an object.
Create an object that conforms to Codable and can store the result - it need to have all the properties of the JSON:
struct MyObject: Codable {
let userId: Int
let id: Int
let title: String
let completed: Bool
}
Create a function to decode:
func decode(data: Data) -> MyObject? {
do {
let result = try JSONDecoder().decode(MyObject.self, from: data)
return result
} catch {
print("\n-->> Error decoding JSON: \(error), \(error)")
return nil
}
}
Use the function:
if let data = data {
// downloaded will store the result from the JSON
let downloaded = decode(data: data)
print(downloaded) // Optional(Test_Swift.MyObject(userId: 1, id: 1, title: "delectus aut autem", completed: false))
print(downloaded?.title ?? "Could not decode") // delectus aut autem
}