iOS create generic Alamofire request using swift

Question

Recently I have started learning iOS app development using swift so I am new to it. I want to implement rest api call in swift & found that we can achieve this using URLRequest . So I have written generic method to call all type(like get, put, post ) of rest api as below.

import Foundation
//import Alamofire

public typealias JSON = [String: Any]
public typealias HTTPHeaders = [String: String];

public enum RequestMethod: String {
    case get = "GET"
    case post = "POST"
    case put = "PUT"
    case delete = "DELETE"
}
public enum Result<Value> {
    case success(Value)
    case failure(Error)
}
public class apiClient{
    private  var base_url:String = "https://api.testserver.com/"
    private func apiRequest(endPoint: String,
                            method: RequestMethod,
                            body: JSON? = nil,
                            token: String? = nil,
                            completionHandler: @escaping (Data?, URLResponse?, Error?) -> Void) {
        let url = URL(string: (base_url.self + endPoint))!
        var urlRequest = URLRequest(url: url)
        urlRequest.httpMethod = method.rawValue
        urlRequest.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
        if let token = token {
            urlRequest.setValue("bearer " + token, forHTTPHeaderField: "Authorization")
        }
        if let body = body {
            urlRequest.httpBody = try? JSONSerialization.data(withJSONObject: body)
        }
        let session = URLSession(configuration: .default)
        let task = session.dataTask(with: urlRequest) { data, response, error in
            //NSLog(error)
            completionHandler(data, response, error)
        }
        task.resume()
    }
    public func sendRequest<T: Decodable>(for: T.Type = T.self,
                                          endPoint: String,
                                          method: RequestMethod,
                                          body: JSON? = nil,
                                          token: String? = nil,
                                          completion: @escaping (Result<T>) -> Void) {
        return apiRequest(endPoint: endPoint, method: method, body:body, token: token) { data, response, error in
            guard let data = data else {
                return completion(.failure(error ?? NSError(domain: "SomeDomain", code: -1, userInfo: nil)))
            }
            do {
                let decoder = JSONDecoder()
                try completion(.success(decoder.decode(T.self, from: data)))
            } catch let decodingError {
                completion(.failure(decodingError))
            }
        }
    }
}

this is how I call it method from controller

public func getProfile(userId :Int, objToken:String) -> Void {
        let objApi = apiClient()
        objApi.sendRequest(for: ProfileDetails.self,
                           endPoint:"api/user/profile/\(userId)",
                           method: .get,
                           token: objToken,
            completion:
            {(userResult: Result<ProfileDetails>) -> Void in
                switch userResult
                {
                case .success(let value):
                    if value.respCode == "01" {
                        print(value.profile)
                        do {
                            //... ddo some taks like store response in local db or else
                        } catch let error as NSError {
                            // handle error
                            print(error)
                        }
                    }
                    else {
                        //do some task
                    }
                    break
                case .failure(let error):
                    print(error)
                    break
                }
        })
    }

I am decoding server response in below model

class ProfileDetails : Response, Decodable {    
    var appUpdate : AppUpdate?
    var profile : Profile?

    enum CodingKeys: String, CodingKey {
        case profile = "profile"
        case respCode = "resp_code"
        case respMsg = "resp_msg"
    }
    public required convenience init(from decoder: Decoder) throws {
        self.init()
        let values = try decoder.container(keyedBy: CodingKeys.self)
        self.profile = try values.decodeIfPresent(Profile.self, forKey: .profile)
        self.respCode = try values.decodeIfPresent(String.self, forKey: .respCode)!
        self.respMsg = try values.decodeIfPresent(String.self, forKey: .respMsg)
    }
}

This code is not able to handle error response like 401, 404 etc from server. So what I am looking for, is to convert this api ( URLRequest )request to generic Alamofire request with error handling like 401, 404 etc. I have install Alamofire pods. Is there anyone who has developed generic Alamofire request method with decoding & error handling ?

Thanks in advance :)

Answer 1

Git link: https://github.com/sahilmanchanda2/wrapper-class-for-alamofire

Here is my version(Using Alamofire 5.0.2 ):

import Foundation
import Alamofire

class NetworkCall : NSObject{

    enum services :String{
        case posts = "posts"
    }
    var parameters = Parameters()
    var headers = HTTPHeaders()
    var method: HTTPMethod!
    var url :String! = "https://jsonplaceholder.typicode.com/"
    var encoding: ParameterEncoding! = JSONEncoding.default

    init(data: [String:Any],headers: [String:String] = [:],url :String?,service :services? = nil, method: HTTPMethod = .post, isJSONRequest: Bool = true){
        super.init()
        data.forEach{parameters.updateValue($0.value, forKey: $0.key)}
        headers.forEach({self.headers.add(name: $0.key, value: $0.value)})
        if url == nil, service != nil{
            self.url += service!.rawValue
        }else{
            self.url = url
        }
        if !isJSONRequest{
            encoding = URLEncoding.default
        }
        self.method = method
        print("Service: \(service?.rawValue ?? self.url ?? "") \n data: \(parameters)")
    }

    func executeQuery<T>(completion: @escaping (Result<T, Error>) -> Void) where T: Codable {
        AF.request(url,method: method,parameters: parameters,encoding: encoding, headers: headers).responseData(completionHandler: {response in
            switch response.result{
            case .success(let res):
                if let code = response.response?.statusCode{
                    switch code {
                    case 200...299:
                        do {
                            completion(.success(try JSONDecoder().decode(T.self, from: res)))
                        } catch let error {
                            print(String(data: res, encoding: .utf8) ?? "nothing received")
                            completion(.failure(error))
                        }
                    default:
                     let error = NSError(domain: response.debugDescription, code: code, userInfo: response.response?.allHeaderFields as? [String: Any])
                        completion(.failure(error))
                    }
                }
            case .failure(let error):
                completion(.failure(error))
            }
        })
    }
}

The above class uses latest Alamofire version (as of now Feb 2020), This class covers almost every HTTP Method with option to send data in Application/JSON format or normal. With this class you get a lot of flexibility and it automatically converts response to your Swift Object.

Look at the init method of this class it has:

1. data: [String,Any] = In this you will put your form data.

2. headers: [String:String] = In this you can send custom headers that you want to send along with the request

3. url = Here you can specify full url, you can leave it blank if you already have defined baseurl in Class. it comes handy when you want to consume a REST service provided by a third party. Note: if you are filling the url then you should the next parameter service should be nil

4. service: services = It's an enum defined in the NetworkClass itself. these serves as endPoints. Look in the init method, if the url is nil but the service is not nil then it will append at the end of base url to make a full URL, example will be provided.

5. method: HTTPMethod = here you can specify which HTTP Method the request should use.

6. isJSONRequest = set to true by default. if you want to send normal request set it to false.

In the init method you can also specify common data or headers that you want to send with every request eg your application version number, iOS Version etc

Now Look at the execute method: it's a generic function which will return swift object of your choice if the response is success. It will print the response in string in case it fails to convert response to your swift object. if the response code doesn't fall under range 200-299 then it will be a failure and give you full debug description for detailed information.

Usage:

say we have following struct:

struct Post: Codable{
    let userId: Int
    let id: Int
    let title: String
    let body: String
}

Note the base url defined in NetworkClass https://jsonplaceholder.typicode.com/

Example 1: Sending HTTP Post with content type Application/JSON

let body: [String : Any] = ["title": "foo",
                                          "body": "bar",
                                          "userId": 1]
        NetworkCall(data: body, url: nil, service: .posts, method: .post).executeQuery(){
            (result: Result<Post,Error>) in
            switch result{
            case .success(let post):
                print(post)
            case .failure(let error):
                print(error)
            }
        }

output:

Service: posts 
data: ["userId": 1, "body": "bar", "title": "foo"]
Post(userId: 1, id: 101, title: "foo", body: "bar")

2. HTTP 400 Request

   NetworkCall(data: ["email":"peter@klaven"], url: " https://reqres.in/api/login ", method: .post, isJSONRequest: false).executeQuery(){ (result: Result) in switch result{ case .success(let post): print(post) case .failure(let error): print(error) } }

output:

Service: https://reqres.in/api/login 
 data: ["email": "peter@klaven"]
Error Domain=[Request]: POST https://reqres.in/api/login
[Request Body]: 
email=peter%40klaven
[Response]: 
[Status Code]: 400
[Headers]:
Access-Control-Allow-Origin: *
Content-Length: 28
Content-Type: application/json; charset=utf-8
Date: Fri, 28 Feb 2020 05:41:26 GMT
Etag: W/"1c-NmpazMScs9tOqR7eDEesn+pqC9Q"
Server: cloudflare
Via: 1.1 vegur
cf-cache-status: DYNAMIC
cf-ray: 56c011c8ded2bb9a-LHR
expect-ct: max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
x-powered-by: Express
[Response Body]: 
{"error":"Missing password"}
[Data]: 28 bytes
[Network Duration]: 2.2678009271621704s
[Serialization Duration]: 9.298324584960938e-05s
[Result]: success(28 bytes) Code=400 "(null)" UserInfo={cf-ray=56c011c8ded2bb9a-LHR, Access-Control-Allow-Origin=*, Date=Fri, 28 Feb 2020 05:41:26 GMT, expect-ct=max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct", Server=cloudflare, Etag=W/"1c-NmpazMScs9tOqR7eDEesn+pqC9Q", x-powered-by=Express, Content-Type=application/json; charset=utf-8, Content-Length=28, Via=1.1 vegur, cf-cache-status=DYNAMIC}

3. with custom headers

   NetworkCall(data: ["username":"sahil.manchanda2@gmail.com"], headers: ["custom-header-key" : "custom-header-value"], url: " https://httpbin.org/post ", method: .post).executeQuery(){(result: Result) in switch result{ case .success(let data): print(data) case .failure(let error): print(error) } }

output:

Service: https://httpbin.org/post 
 data: ["username": "sahil.manchanda2@gmail.com"]
{
  "args": {}, 
  "data": "{\"username\":\"sahil.manchanda2@gmail.com\"}", 
  "files": {}, 
  "form": {}, 
  "headers": {
    "Accept": "*/*", 
    "Accept-Encoding": "br;q=1.0, gzip;q=0.9, deflate;q=0.8", 
    "Accept-Language": "en;q=1.0", 
    "Content-Length": "41", 
    "Content-Type": "application/json", 
    "Custom-Header-Key": "custom-header-value", 
    "Host": "httpbin.org", 
    "User-Agent": "NetworkCall/1.0 (sahil.NetworkCall; build:1; iOS 13.2.2) Alamofire/5.0.2", 
    "X-Amzn-Trace-Id": "Root=1-5e58a94f-fab2f24472d063f4991e2cb8"
  }, 
  "json": {
    "username": "sahil.manchanda2@gmail.com"
  }, 
  "origin": "182.77.56.154", 
  "url": "https://httpbin.org/post"
}

typeMismatch(Swift.String, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode String but found a dictionary instead.", underlyingError: nil))

In the last example you can see typeMismatch at the end, I tried to pass [String:Any] in the executeQuery but since the Any doesn't confirm to encodable I had to use String.

Answer 2

I use EVReflection with alamofire and i think this is one of the best combination to work with.

Use URLRequestConvertible protocol of Alamofire.

This is what i follow.

Just for reference purpose.

Make enum for your all endpoint and confirm that enum to URLRequestConvertible.

enum Router: URLRequestConvertible { 

//your all endpoint
static var authToken = ""
case login([String:Any])

var route: Route {
        switch self {
        case .Login(let dict):
            return Route(endPoint: "api/addimagedata", httpMethod: .post)
        }
    }

func asURLRequest() throws -> URLRequest {

        var requestUrl = EnvironmentVariables.baseURL
        if let queryparams = route.queryParameters {
            requestUrl.appendQueryParameters(queryparams)
        }
        var mutableURLRequest = URLRequest(url: requestUrl.appendingPathComponent(route.endPath))
        mutableURLRequest.httpMethod = route.method.rawValue


        //FIXME:- Change the Userdefault Key
        if Router.authToken.isEmpty, let token = UserDefaults.standard.string(forKey: "Key"), !token.isEmpty {
            Router.authToken = token
        }

        //FIXME:- Set Mutable Request Accordingly
        mutableURLRequest.setValue("Bearer \(Router.authToken)", forHTTPHeaderField: "Authorization")
        mutableURLRequest.setValue("application/json", forHTTPHeaderField: "Content-Type")
        mutableURLRequest.setValue("application/json", forHTTPHeaderField: "Accept")

        if route.method == .get {
            return try Alamofire.URLEncoding.default.encode(mutableURLRequest, with: route.parameters)
        }
        return try Alamofire.JSONEncoding.default.encode(mutableURLRequest, with: route.parameters)
    }


}

Make One Structure as per your requirement.

struct Route {

    let endPath: String
    let method: Alamofire.HTTPMethod
    var parameters: Parameters?
    var queryParameters : [String:String]?

    var encoding: Alamofire.ParameterEncoding {
        switch method {
        case .post, .put, .patch, .delete:
            return JSONEncoding()
        default:
            return URLEncoding()
        }
    }
}

Now make one generic function that accept URLRequestConvertible and return your model in closure. Something like this.

func GenericApiCallForObject<T : URLRequestConvertible, M : EVObject>(router : T, showHud : Bool = true ,responseModel : @escaping (M) -> ()) {

    view.endEditing(true)

    if !isConnectedToInternet {
        showNetworkError()
        return
    }

    if showhud ? showHud() : ()

    Alamofire.request(router).responseObject { (response: DataResponse<M>) in

        self.HandleResponseWithErrorForObject(response: response) { (isSuccess) in
            if isSuccess {
                if let value = response.result.value {
                    responseModel(value)
                }
            }
        })
    }
}

Now make one generic function that accept your response and handle the error for you. Something like this.

func HandleResponseWithErrorForObject<M : EVObject>(response : DataResponse<M>, isSuccess : @escaping (Bool) -> ()) {

        print(response)
        hideHud()
        switch response.response?.statusCode ?? 0 {
        case 200...299:
            isSuccess(true)
        case 401:
            isSuccess(false)
            showSessionTimeOutError()
        case -1005,-1001,-1003:
            break
        default:
            isSuccess(false)
            // Parse your response and show error in some way.

        }
    }

Now Finally, how to use it right??! Indeed now its very simple just two lines of code and you are good to go.

GenericApiCallForObject(router: Router.Login(["xyz":"xyz"])) { (response : GeneralModel) in
    print(response)
}

Please note that this will only work if you are getting object in response. If there is an array or string you have to make separate function for that and procedure for that is same as above. You will only get response if there is a success otherwise HandleResponseWithErrorForObject function will automatically handle it for you. Also, some variables might be missing in above explanation.

Answer 3

I'm sharing a specific part for error handling on my REST api. It will decode inside the following block and probably you can use it for reference.

As you can see that's very simple getting a code and translate into an enumeration. Alamofire allow that but it depends on your version of library. Sometimes depends your REST api how handle errors internally, they can not throw a code for example if its Java backend, they can encapsulate the exceptions.

public enum RESTError: Error {
    case BadRequest(String, [String]?)
    case InternalError(String)
    case UnAuthorized(String, [String]?)
    case NotFound(String)
    case Success

    /// <#Description#>
    ///
    /// - Parameters:
    ///   - code: <#code description#>
    ///   - message: <#message description#>
    ///   - globalErrors: <#globalErrors description#>
    /// - Returns: <#return value description#>
    public static func fromCode(code: Int, message: String, globalErrors: [String]? = nil) -> RESTError {
        switch code {
        case 400: return RESTError.BadRequest(message, globalErrors)
        case 401: return RESTError.UnAuthorized(message, globalErrors)
        case 500: return RESTError.InternalError(message)
        case 404: return RESTError.NotFound(message)
        default: break
        }
        return RESTError.Success
    }
}

Alamofire.request(urlRequest)
                        .validate(statusCode: 200...500)
                        .responseJSON(completionHandler: { (response: (DataResponse<Any>)) in
                            if let statusCode = response.response?.statusCode {
                                if statusCode != 200 {
                                    // call handler errors function with specific message
                                    if let arrayDictionary = response.result.value as? Dictionary<String,AnyObject> {
                                        var error: RESTError?
                                        if let code = arrayDictionary["status"] as? Int {
                                            let message = arrayDictionary["message"] as! String
                                            let globalErrors = arrayDictionary["globalErrors"] as? [String]
                                            error = RESTError.fromCode(code: code, message: message, globalErrors: globalErrors)
                                        } else {
                                            // Build from error message without code.
                                            let message = arrayDictionary["error_description"] as! String
                                            let codeMsg = arrayDictionary["error"] as! String
                                            let globalErrors = arrayDictionary["globalErrors"] as? [String]
                                            if codeMsg == "invalid_token" && message.starts(with: "Access token expired") {

                                                return
                                            } else {
                                                error = RESTError.fromCode(code: codeMsg, message: message, globalErrors: globalErrors)
                                            }
                                        }
                                        if let _ = error {
                                            errorHandler(error!)
                                        } else {
                                            errorHandler(RESTError.InternalError("Internal API rest error."))
                                        }
                                    } else {
                                        errorHandler(RESTError.fromCode(code: statusCode, message: ""))
                                    }
                                } else {
                                    if let arrayDictionary = response.result.value as? Dictionary<String,AnyObject> {
                                        handler(arrayDictionary)
                                    }
                                }
                            } else {
                                if let error = response.error {
                                    errorHandler(RESTError.InternalError(error.localizedDescription))
                                }
                            }
                        })

Answer 4

You probably need this function that uses the alamofilre Session Manager to perform requests. You can also set the cookies ant headers etc.. to this session manager so that you will have them to the rest of your requests.

import Alamofire

class NetworkManager : NSObject {
internal typealias SuccessCompletion = (Int?, Any?) -> Void?
internal typealias FailCompletion = (Int?, Error, Any?) -> Void?
var sessionManager : SessionManager!
var request : Request?
var headers : HTTPHeaders! = [:]


    override init() {
        let configuration = URLSessionConfiguration.default
        configuration.httpAdditionalHeaders = SessionManager.defaultHTTPHeaders
        sessionManager = SessionManager(configuration: configuration)
     }


func sendRequest(url: String?, method: String, parameters: [String: Any], success: SuccessCompletion?, fail: FailCompletion?){
    var encoding : ParameterEncoding!
    if  HTTPMethod(rawValue: method) == HTTPMethod.post {
        encoding = JSONEncoding.default
    } else {
        encoding = URLEncoding.default
    }

    request = sessionManager.request(url ?? "", method: HTTPMethod(rawValue: method)!, parameters: parameters, encoding: encoding, headers: headers)
    .validate()
    .responseData{response in
        switch (response.result) {
        case .success:
            let statusCode = response.response?.statusCode
            success?(statusCode, response.result.value)
            self.request = nil
            break
        case .failure(let error):
            let statusCode = response.response?.statusCode
            fail?(statusCode, error, response.data)
            self.request = nil
            break
        }
    }
}

}

EDIT

To add Headers you can just add a function like this..

func updateJSONHeader(token: String) {
        self.clearHeaders()
        headers["AuthorizationToken"] = "\(token)"
    }

For cookie

func setCookie(_ cookie : HTTPCookie?){
    if let cookie = cookie {
        HTTPCookieStorage.shared.setCookie(cookie)
    }
}

Clear headers

func clearHeaders(){
    headers = [:]
}

And keep in mind that it's a singleton class so whenever you change anything unless your server make some changes you still have your configuration, ex. the headers

Answer 5

The best way is create a custom validate method using DataRequest extension:

func customValidate() -> Self {
        return self.validate { _, response, data -> Request.ValidationResult in
            guard (400...599) ~= response.statusCode else { return .success(()) }
            guard let data = data else { return .failure(MyAppGeneralError.generalResponseError) }

            guard let errorResponse = try? JSONDecoder().decode(MyAppResponseError.self, from: data) else {
                return .failure(MyAppGeneralError.generalResponseError)
            }

            if response.statusCode == 401 {
                return .failure(MyAppGeneralError.unauthorizedAccessError(errorResponse))
            }

            return .failure(MyAppGeneralError.responseError(errorResponse))
        }
    }

With a client with a generic function where the generic is decodable using our custom validate.

class APIClient {
    var session: Session

    init(session: Session = Session.default) {
        self.session = session
    }

    @discardableResult
    func performRequest<T: Decodable>(request: URLRequestConvertible,
                                      decoder: JSONDecoder = JSONDecoder(),
                                      completion: @escaping (Result<T, AFError>) -> Void) -> DataRequest {
        return AF.request(request).customValidate().responseDecodable(decoder: decoder, completionHandler: { (response: DataResponse<T, AFError>) in
            completion(response.result)
        })
    }

    func getProfile(userID: Int, _ completion: @escaping (Result<UserToken, AFError>) -> Void) {
        performRequest(request: APIRouter.profile(userID: userID), completion: completion)
    }
}

using a router a:

enum APIRouter: URLRequestConvertible {
    case profile(userId :Int)

    static let baseURLString = "https://myserver.com"

    var method: HTTPMethod {
        switch self {
        case .profile:
            return .get
        }
    }

    var path: String {
        switch self {
        case .profile(let userID):
            return "profile/\(userID)"
        }
    }

    var body: Parameters {
        return [:]
    }

    // MARK: URLRequestConvertible
    func asURLRequest() throws -> URLRequest {
        let url = try APIRouter.baseURLString.asURL()

        var urlRequest = URLRequest(url: url.appendingPathComponent(path))
        urlRequest.httpMethod = method.rawValue

        // Common Headers
        urlRequest.setValue("application/json", forHTTPHeaderField: "Accept")


        // Encode body
        urlRequest = try JSONEncoding.default.encode(urlRequest, with: body)

        return urlRequest
    }
}

Answer 6

import Foundation

import UIKit import Alamofire import SwiftyJSON

class AFWrapper: NSObject {

static let sharedInstance = AFWrapper()

//TODO :-
/* Handle Time out request alamofire */


func requestGETURL(_ strURL: String, success:@escaping (JSON) -> Void, failure:@escaping (Error) -> Void)
{
    Alamofire.request(strURL).responseJSON { (responseObject) -> Void in
        //print(responseObject)
        if responseObject.result.isSuccess {
            let resJson = JSON(responseObject.result.value!)
            //let title = resJson["title"].string
            //print(title!)
            success(resJson)
        }

        if responseObject.result.isFailure {
            let error : Error = responseObject.result.error!
            failure(error)
        }
    }
}

func requestPOSTURL(_ strURL : String, params : [String : AnyObject]?, headers : [String : String]?, success:@escaping (JSON) -> Void, failure:@escaping (Error) -> Void){
    Alamofire.request(strURL, method: .post, parameters: params, encoding: JSONEncoding.default, headers: headers).responseJSON { (responseObject) -> Void in
        //print(responseObject)
        if responseObject.result.isSuccess {
            let resJson = JSON(responseObject.result.value!)
            success(resJson)
        }
        if responseObject.result.isFailure {
            let error : Error = responseObject.result.error!
            failure(error)
        }
    }
}

}

Answer 7

This is something I have been working on! Not finished yet but could solve your issue. you can upgrade it to whatever you want.

typealias

 typealias Closure<T> = (T)->()
 typealias JSON = [String: Any]

Extension

extension JSONDecoder{
func decode<T : Decodable>(_ model : T.Type,
                           result : @escaping Closure<T>) ->Closure<Data>{
    return { data in
        if let value = try? self.decode(model.self, from: data){
            result(value)
        }
    }
}

Protocol //MARK:- protocol APIResponseProtocol

protocol APIResponseProtocol{
    func responseDecode<T: Decodable>(to modal : T.Type,
                              _ result : @escaping Closure<T>) -> APIResponseProtocol
    func responseJSON(_ result : @escaping Closure<JSON>) -> APIResponseProtocol
    func responseFailure(_ error :@escaping Closure<String>)
}

Request :

       let configuration = URLSessionConfiguration.default
        configuration.timeoutIntervalForRequest = 300 // seconds
        configuration.timeoutIntervalForResource = 500
        alamofireManager = Alamofire.SessionManager(configuration: configuration)

  func getRequest(forAPI api: String, params: JSON) -> APIResponseProtocol {
          let responseHandler = APIResponseHandler()
            var parameters = params
             parameters["token"] = preference.string(forKey: USER_ACCESS_TOKEN)
          alamofireManager.request(api,
                          method: .get,
                          parameters: parameters,
                          encoding: URLEncoding.default,
                          headers: nil)
              .responseJSON { (response) in
                  print("Å api : ",response.request?.url ?? ("\(api)\(params)"))


                  switch response.result{
                  case .success(let value):
                      let json = value as! JSON
                      let error = json.string("error")
                      guard error.isEmpty else{

                          responseHandler.handleSuccess(value: value,data: response.data ?? Data())
                  case .failure(let error):
                      responseHandler.handleFailure(value: error.localizedDescription)
                  }
          }


          return responseHandler
      }

Response Hanlder:

class APIResponseHandler : APIResponseProtocol{

init(){
}
var jsonSeq : Closure<JSON>?
var dataSeq : Closure<Data>?
var errorSeq : Closure<String>?

func responseDecode<T>(to modal: T.Type, _ result: @escaping Closure<T>) -> APIResponseProtocol where T : Decodable {

    let decoder = JSONDecoder()
    self.dataSeq =  decoder.decode(modal, result: result)
    return self
}

func responseJSON(_ result: @escaping Closure<JSON>) -> APIResponseProtocol {
    self.jsonSeq = result
    return self
}
func responseFailure(_ error: @escaping Closure<String>) {
    self.errorSeq = error

  }




func handleSuccess(value : Any,data : Data){
    if let jsonEscaping = self.jsonSeq{
        jsonEscaping(value as! JSON)
    }
    if let dataEscaping = dataSeq{
        dataEscaping(data)

    }
}
func handleFailure(value : String){
    self.errorSeq?(value)
 }

}

USAGE:

self?.apiInteractor?
        .getRequest(forAPI: "https://maps.googleapis.com/maps/api/directions/json",
                    params: [
                        "origin" : "\(pickUpLatitude),\(pickUpLongitude)",
                        "destination" :"\(dropLatitude),\(dropLongitude)",
                        "mode" : "driving",
                        "units" : "metric",
                        "sensor" : "true",
                        "key" : "\(UserDefaults.value(for: .google_api_key) ?? "")"
        ])
        .responseDecode(to: GoogleGeocode.self, { [weak self] (googleGecode) in
            guard let welf = self,
                let route = googleGecode.routes.first,
                let leg = route.legs.first else{return}
            welf.tripDetailModel?.arrivalFromGoogle = leg.duration.text ?? ""
            welf.drawRoute(forRoute: route)
            welf.calculateETA()
        })
        .responseJSON({ (json) in
            debugPrint(json.description)
        })
        .responseFailure({ (error) in
            debug(print: error)
        })

Answer 8

just part of code, but try

let req = Alamofire.request(url, method: .get, parameters: nil)

then you can handle response code by using

req.response?.statusCode

and handle response by for example

req.responseString(completionHandler: <#T##(DataResponse<String>) -> Void#>)
  or
req.responseJSON(completionHandler: <#T##(DataResponse<Any>) -> Void#>)

you have good example here