How to set delegate for Alamofire respone

Question

I am new to IOS. And I am using Alamofire for making network request. I have been very much successful in doing following...

Making request with parameters
Showing activity indicator
Getting Response and hiding activity indicator
Parsing response into modal

I have good concept of OOP. and I have good experience of working in android. In android I use to make a centralized class for services, and calls it from activities, and then I pass the result using callbacks.

In this way the it is more compact and avoids me in writing same code again and again. I search on it, and found that delegate are the same thing as Callbacks/Interfaces in java/android.

My Question:

Can Any one tell me how to make a Alamofire code in one class and how to call that from other View controllers with different number and type of parameters. and with different type of results to send back into related View controller? is it possible and how using swift??

As you have decided to adopt a better approach. I would like to suggest you to check `PromiseKit`. It has already embedded the above part that you are trying to achieve. — Kamran, Jun 21 '18 at 07:24
@Androidteem: Please check my answer below. I have shown you an example of closure. — iPeter, Jun 21 '18 at 07:44

Shahrukh · Accepted Answer · 2018-06-21T11:21:52.380

2

Create one swift file with WebServicesCall or your preferred name and use following code. here I am using SwiftyJSON and Alamofire.

import UIKit
import Alamofire
import SwiftyJSON

struct WebService {
static func requestService(url: URL, method: HTTPMethod, parameters: Parameters, headers: HTTPHeaders? = nil, showLoaderFlag: Bool, viewController: UIViewController, completion: @escaping (_ success: JSON) -> Void) {
        /* check for internet connection */
        if(Reachability.isConnectedToNetwork()) {
            /* Show Loader here */

            print("Web Service - \(url)")
            print("Header - \(String(describing: headers))")
            print("Parameters - \(parameters)")

            /* Request configure */
            AlmofireService.Manager.request(url, method: method, parameters: parameters, encoding: JSONEncoding.default, headers: header) .responseJSON { response in
                print("Response - \(response)")

                switch response.result {
                case .success(_):
                    /* Hide loader here */

                    let json = JSON(response.result.value!)

                    completion(json)

                case .failure(_):
                    print("Request failed with error: \(response.result.error ?? "" as! Error)")

                    if response.result.error?._code == NSURLErrorTimedOut {
                        //TODO: show response time out alert or message here
                    } else {
                        //TODO: show response failure alert or message here
                    }

                    /* Hide loader here */

                    completion(JSON.null)
                }
            }
        } else {
            print("No internet connection")

            //TODO: show no internet connection alert or message here

            let json: JSON = ["status": "nointernet",
                          "code": 503]
            completion(json)
        }
    }
    }

And then call as following when your need

func callWebService() {
        let parameters: [String: Any] = ["key": "value"] //for post request
        let headers: [String: String] = ["key": "value"]
        let url = //your url here

        WebService.requestService(url: url, method: .post, parameters: parameters, headers: headers, showLoaderFlag: true, viewController: self, completion: { response in

            guard response["code"].int != 503 else {
                print("No internet connection")
                return
            }

            guard response != .null else {
                return
            }

            /* Handle your success response here */

        })
    }

edited Jun 21 '18 at 11:21

answered Jun 21 '18 at 09:42

Shahrukh

740
7
25

I have one question. What if the response is not nil and the response contains a reason able error message (where success == false) – Android teem Jun 21 '18 at 10:16
on `print("Request failed with error: \(response.result.error ?? "" as! Error)")` this line you will get error messge – Shahrukh Jun 21 '18 at 10:17
Thats fine but it must also be delegated to main view controller – Android teem Jun 21 '18 at 10:18
Now check my updated code for no internet connection you can modified like this to for other error messages – Shahrukh Jun 21 '18 at 10:24
I am trying your answer but getting this error Cannot load underlying module for 'SwiftyJSON' – Android teem Jun 21 '18 at 10:32
If this ans was helpful to you then please up vote so it can help other – Shahrukh Jun 21 '18 at 10:38
I am trying this, then I will furthur comment on it – Android teem Jun 21 '18 at 10:41
well adding point it is good to use default case for /* Hide loader here */ – Android teem Jun 21 '18 at 10:44
there is an error Use of unresolved identifier 'Reachability' – Android teem Jun 21 '18 at 11:05
there are alot of errors Type 'Reachability' has no member 'isConnectedToNetwork' – Android teem Jun 21 '18 at 11:12
For `Reachability` https://stackoverflow.com/a/25623647/5523205 and use swift 3/4 updated code – Shahrukh Jun 21 '18 at 11:13
and there is another error Use of unresolved identifier 'json' on line guard json["code"].int != 503 else { print("No internet connection") return } – Android teem Jun 21 '18 at 11:17
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/173552/discussion-between-shahrukh-and-android-teem). – Shahrukh Jun 21 '18 at 11:24

Ajay saini · Answer 2 · 2018-06-21T07:56:45.197

Create a NSObject class and and create a class level function inside it. and call it from any other class

import Alamofire

class Network: NSObject {

class func API_PostData(_ strURL: String, parameter Params: NSDictionary, successWithStatus1Closure: @escaping (AnyObject?) -> (), successWithStatus0Closure: @escaping (AnyObject?) -> (), failurClosure: @escaping (String?)-> ())
    {

        let Param: [String: Any] = Params.mutableCopy() as! [String : Any]


        let complite_url = BASE_URL+strURL


        if Reachability.isConnectedToNetwork(){



            Alamofire.request(complite_url, method: .post, parameters: Param ,encoding: JSONEncoding.default).responseJSON {
                response in
                if(response.result.error != nil)
                {
                    let error = response.result.error
                    if (error?.localizedDescription == "The request timed out."){
                        failurClosure("The request timed out.");
                        return
                    }
                    if (error?.localizedDescription == "Could not connect to the server."){
                        failurClosure("Could not connect to the server.");
                        return
                    }
                    if (error?.localizedDescription == "The network connection was lost."){
                        failurClosure("The network connection was lost.");
                        return
                    }
                }
                let dictResponse = response.result.value as? NSDictionary

                print("Response",response)

                if dictResponse is Dictionary<AnyHashable,Any> {
                    print("Yes, it's a Dictionary")
                }
                else{
                    print("No, it's a not a Dictionary")
                    failurClosure("Active internet connection required")
                    return
                }

                let isSuccess = dictResponse!["success"] as! Int

                if isSuccess == 1
                {
                    successWithStatus1Closure(dictResponse)
                }else{
                    successWithStatus0Closure(dictResponse)
                }

            }
        }else {

            print("Active internet connection required");
            failurClosure("Active internet connection required")
            return
        }

    }
    }

and use it like

Network.API_PostData

and xCode will autocompleted the method

Uses Example in your view controller create a method

func callApi(){
    let para = ["user_id" : USER_ID_STR,
                "page" : String(page),
                "item_per_page" : "15"
        ] as NSDictionary
    SVProgressHUD.show()
    GlobalClass.API_PostData("notifications/activities", parameter: para, successWithStatus1Closure: { (response) in

        print("response \(response)")
        SVProgressHUD.dismiss()
    }, successWithStatus0Closure:{ (response) in
        print("response \(response)")
        SVProgressHUD.dismiss()
    }, failurClosure: { (error) in
        print("error \(error ?? "ddd")")
        GlobalClass.showAlert(alertTitle: "", alertMsg: error!, view: self)
        SVProgressHUD.dismiss()
    })
}

and call it like

callApi()

how to use it and how to send back data to main view controller in 3 case , success, fail and request time out exception ??? — Android teem, Jun 21 '18 at 07:50
You can see the SuccessClosure and FailiureClosure . these are escaping closure return to the main class . lemmi give you a example — Ajay saini, Jun 21 '18 at 07:51
what is difference between successWithStatus1Closure(dictResponse) and successWithStatus0Closure(dictResponse) — Android teem, Jun 21 '18 at 08:02
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/173536/discussion-between-android-teem-and-ajay-saini). — Android teem, Jun 21 '18 at 08:02

score 0 · Answer 3 · answered Jun 21 '18 at 07:18

0

You can achieve your requirement by writing Callback methods or Closures. For example:

func yourMethodName(completion:@escaping (YourModelClass) -> Void,onError:@escaping (Error) -> Void) {
    let dataRequest = RequestObject()
    dataRequest.apiURL = YourApiURl
    dataRequest.headers = DesiredHeaders
    dataRequest.requestType = RequestType

    //This will be your method for the webservice call, whenever you get success or error, return a callback to the calling class via completion.
    NetworkManager.getDataFor(Request: dataRequest, success: {response in
        //print(response.responseObject!)
        let model = YourModelClass.init(WithDictionary: response.responseObject as? [String : Any])
        completion(model)
    }, failure: {error in
        onError(error)
  })
}

Hope this helps. For any query feel free to leave a comment.

answered Jun 21 '18 at 07:18

iPeter

1,330
10
26

So, he has to copy this method at n number of places for n number of API's? – Kamran Jun 21 '18 at 07:27
@Kamran: To create different models for different responses, he have to write different methods right? – iPeter Jun 21 '18 at 07:31
No, one method can do it. – Kamran Jun 21 '18 at 07:32
How can you create different models in one method? – iPeter Jun 21 '18 at 07:42
By conforming models to `Decodable` and then having a `generic method` that takes the `model type` and return the `decoded object`. – Kamran Jun 21 '18 at 07:47
I think Kamran is right. How about returning the whole response to calling view controller., and calling controller manage the response in its on way – Android teem Jun 21 '18 at 07:52
Thats your choice what you want in your calling controller, but this way using a closure you can get the callback. – iPeter Jun 21 '18 at 07:54

score 0 · Answer 4 · answered Jun 21 '18 at 07:18

Try this

Swift

In WebService Class : post the notification

NotificationCenter.default.post(name: NSNotification.Name(rawValue: "yourNotificationName"), object: nil)

In your class where you want to receive the response : register first for the notification, and write a method to handle it. You give the corresponding selector to the method. // view did load

NotificationCenter.default.addObserver(self, selector: #selector(yourClass.handleUpdatedData), name: NSNotification.Name(rawValue: "yourNotificatioName"), object: nil)

-(void)handleUpdatedData:(NSNotification *)notification {
    NSLog(@"recieved");
    [self.tableView reloadData];
}

Objective C...

In WebService Class : post the notification

[[NSNotificationCenter defaultCenter] postNotificationName:@"DataUpdated"
                                                        object:self];

In your class where you want to receive the response : register first for the notification, and write a method to handle it. You give the corresponding selector to the method. // view did load

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(handleUpdatedData:)
                                             name:@"DataUpdated"
                                           object:nil];

-(void)handleUpdatedData:(NSNotification *)notification {
    NSLog(@"recieved");
    [self.tableView reloadData];
}

It can be done using `NotificationCenter` but it is a terrible idea to achieve using this way. Closures with tuples or delegate is far better solutions than this. — onCompletion, Jun 21 '18 at 07:26

How to set delegate for Alamofire respone

4 Answers4