How to decode JSON Data in Swift

Question

So I am having a hard time understanding how swift handles API data.

My app calls for a Bearer token, and the API returns a Token and Expires , i need to extract the token so i can make another API call later.

i can see in the print statement the token and expires data, but how do i extract just the token out.

import Foundation
#if canImport(FoundationNetworking)
import FoundationNetworking
#endif

class MyRequestController {
    func getToken() {
    
        let semaphore = DispatchSemaphore (value: 0)

        var request = URLRequest(url: URL(string: "URL")!,timeoutInterval: Double.infinity)
        request.addValue("Basic userinfo", forHTTPHeaderField: "Authorization")
        request.addValue("AWSALB=efzS5NSzJXZ4OpGhrFJLjdemrPBlAW5H36T6T5AVneKb+5F9PGVi1VMmBpGe8SKom145AhE2MM6vZAvLGFVQezt2qG6hC8a12mshJewTwJYJFq9YCDfkK49kRhdE; AWSALBCORS=efzS5NSzJXZ4OpGhrFJLjdemrPBlAW5H36T6T5AVneKb+5F9PGVi1VMmBpGe8SKom145AhE2MM6vZAvLGFVQezt2qG6hC8a12mshJewTwJYJFq9YCDfkK49kRhdE", forHTTPHeaderField: "Cookie")

        request.httpMethod = "POST"

        let task = URLSession.shared.dataTask(with: request) { data, response, error in
          guard let data = data else {
            print(String(describing: error))
            semaphore.signal()
            return
          }
            print(String(data: data, encoding: .utf8)!)
          semaphore.signal()
        }

        task.resume()
        semaphore.wait()
    }
    
    struct TokenInfo: Decodable {
        let token: String
    }

}

Research Codable with JSONDecoder or use JSONSerialization — Joakim Danielson
– Joakim Danielson, Commented Apr 15, 2022 at 19:18

iPriyonto · Accepted Answer · 2022-04-15 19:29:17Z

2

I am assuming the TokenInfo is your desired output from this method. You are on the right track. The next step is to convert the data into TokenInfo model using JSONDecoder.

    import Foundation
    #if canImport(FoundationNetworking)
    import FoundationNetworking
    #endif
    
    class MyRequestController {
        func getToken() {
            
            let semaphore = DispatchSemaphore (value: 0)
            
            var request = URLRequest(url: URL(string: "URL")!,timeoutInterval: Double.infinity)
            request.addValue("Basic userinfo", forHTTPHeaderField: "Authorization")
            request.addValue("AWSALB=efzS5NSzJXZ4OpGhrFJLjdemrPBlAW5H36T6T5AVneKb+5F9PGVi1VMmBpGe8SKom145AhE2MM6vZAvLGFVQezt2qG6hC8a12mshJewTwJYJFq9YCDfkK49kRhdE; AWSALBCORS=efzS5NSzJXZ4OpGhrFJLjdemrPBlAW5H36T6T5AVneKb+5F9PGVi1VMmBpGe8SKom145AhE2MM6vZAvLGFVQezt2qG6hC8a12mshJewTwJYJFq9YCDfkK49kRhdE", forHTTPHeaderField: "Cookie")
            
            request.httpMethod = "POST"
            
            let task = URLSession.shared.dataTask(with: request) { data, response, error in
                guard let data = data else {
                    print(String(describing: error))
                    semaphore.signal()
                    return
                }
                do {
                    let tokenData = try JSONDecoded().decode(TokenInfo.self, from: data)
                    // Do something with tokenData
                    // Print(tokenData.token)
                } catch {
                    // Handle error
                }
                semaphore.signal()
            }
            
            task.resume()
            semaphore.wait()
        }
        
        struct TokenInfo: Decodable {
            let token: String
        }
        
    }

answered Apr 15, 2022 at 19:29

iPriyonto

513 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Bnd10706 Over a year ago

Thank you, I was close, but quick question, when i do this. Data().token = jsonData.token the value is not stored. am i missing something with this?I have a data model Data() where I am storing my API data, and i want to store the token there for sure later in the applciation.

iPriyonto Over a year ago

If you want to store the token for later use for different endpoints you will have to store it. There are several ways to do it. You can store it using UserDefaults with a couple of lines of codes although it is not recommended at all. For sensitive information like auth token should be stored in Keychain.

Collectives™ on Stack Overflow

How to decode JSON Data in Swift

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related