Data API Token Refresh

refreshTokenExample.swift

// refresh token -> (token, expiry, error)
class func refreshToken(for auth: String, completion: @escaping (String, Date, String) -> Void) {
        
    guard   let path = UserDefaults.standard.string(forKey: "fm-db-path"),
            let baseURL = URL(string: path) else { return }
        
    let url = baseURL.appendingPathComponent("/sessions")
    let expiry = Date(timeIntervalSinceNow: 900)   // 15 minutes
        
    var request = URLRequest(url: url)
    request.httpMethod = "POST"
    request.setValue("Basic \(auth)", forHTTPHeaderField: "Authorization")
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        
    URLSession.shared.dataTask(with: request) { data, _, error in
            
        guard   let data      = data, error == nil,
                let json      = try? JSONSerialization.jsonObject(with: data) as! [String: Any],
                let response  = json["response"] as? [String: Any],
                let messages  = json["messages"] as? [[String: Any]],
                let code      = messages[0]["code"] as? String else { return }
            
        guard let token = response["token"] as? String else {
            print(messages)
            return
        }
            
        UserDefaults.standard.set(token, forKey: "fm-token")
        UserDefaults.standard.set(expiry, forKey: "fm-token-expiry")
            
        completion(token, expiry, code)
            
    }.resume()
}