Alamofire implementation for generic api calls in swift

ViewController.swift

import UIKit
import Alamofire
import iOSDropDown

class ViewController: UIViewController {
    
    //Variables
    
    @IBOutlet weak var dropDownTxtField: DropDown!
    
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        getFoodCourtData()
        dropDownTxtField.optionArray = ["Option 1", "Option 2", "Option 3"]
        dropDownTxtField.didSelect { (text, index, id) in
            //print("Selected Text is: \(text)")
            //print("Selected Index is: \(index)")
            //print("Selected Id is: \(id)")
            self.dropDownTxtField.text = text
            print(self.dropDownTxtField.text ?? "")
        }
        
    }
    
}

//Drop 
extension ViewController {
    
    
    
}

extension ViewController {
    
    func getFoodCourtData() {
        
        view.makeToastActivity(.center)
        
        let url = "http://13.234.40.117/qhospitality/index.php/Webservice/get_food_court_cart_list_by_employee_id"
        
        let params = ["co_works_employee_id": 2]
        
        WebServiceHelper.instance.getServiceData(url: url, method: .post, parameters: params, encodingType: URLEncoding.default, headers: [:]) { [unowned self] (returnedResponse: FoodCourtData!, errorString: String?) in
            
            if errorString != nil {
                DispatchQueue.main.async {
                    self.view.hideToastActivity()
                    self.view.makeToast(errorString, duration: 2.0, position: .bottom)
                }
            }
            else {
                if let returnedResponse = returnedResponse {
                    
                    if returnedResponse.code == 0 {
                        //Success
                        self.view.hideToastActivity()
                        print(returnedResponse.results)
                    }
                    else {
                        //Failure
                        DispatchQueue.main.async {
                            self.view.hideToastActivity()
                            self.view.makeToast(returnedResponse.message, duration: 2.0, position: .bottom)
                        }
                    }
                    
                }
            }
            
            
        }
        
    }
    
    
    //        WebServiceHelper.instance.getServiceData(url: url, method: .post, parameters: params, encodingType: URLEncoding.default, headers: [:]) { [unowned self] (foodCourtResponse: FoodCourtData),<#arg#>  in
    //
    //            if foodCourtResponse.code == 0 {
    //                print(foodCourtResponse.results)
    //                DispatchQueue.main.async {
    //                    self.view.hideToastActivity()
    //                }
    //            }
    //            else {
    //                print(foodCourtResponse.message)
    //                DispatchQueue.main.async {
    //                    self.view.hideToastActivity()
    //                    self.view.makeToast(foodCourtResponse.message, duration: 2.0, position: .bottom)
    //                }
    //            }
    //
    //        }
    //
    //    }
}

WebServiceHelper.swift

import Foundation
import Alamofire

class WebServiceHelper {
    static let instance = WebServiceHelper()
    let connectivityManager = NetworkReachabilityManager()
    let manager = Alamofire.SessionManager()
    
    func getServiceData <T: Codable> (url: String, method: HTTPMethod, parameters: [String:Any], encodingType: ParameterEncoding, headers: [String:String], completion: @escaping (T?, String?) ->()) {
        
        if connectivityManager?.isReachable ?? false {
            //print("Network is Reachable")
            let manager = Alamofire.SessionManager.default
            manager.session.configuration.timeoutIntervalForRequest = 20
            
            manager.request(url, method: method, parameters: parameters, encoding: encodingType, headers: headers).responseJSON { (response) in
                
                if response.error != nil {
                    //debugPrint(response.error?.localizedDescription ?? "")
                    completion(nil, response.error?.localizedDescription)
                }
                else {
                    guard let data = response.data else {return completion(nil, response.error?.localizedDescription)}
                    let decoder = JSONDecoder()
                    
                    do{
                        let returnedResponse = try decoder.decode(T.self, from: data)
                        completion(returnedResponse, nil)
                    }catch{
                        //debugPrint(error)
                        completion(nil, error.localizedDescription)
                    }
                    
                }
                
            }
            
        }
        else {
            //print("Network Not Reachable")
            completion(nil, "Network Not Reachable")
        }
        
    }
    
}