CLOVA Chatbot Custom API

To integrate with a custom chatbot, copy and store the invoke URL and secret key of the stage created.

Requests

Sending a request to CLOVA Chatbot from a custom channel.

• Http Method: POST

• Headers

Request signature headers

• Signature definition (X-NCP-CHATBOT_SIGNATURE)

  • Algorithm: HmacSHA256

  • SecretKey: it is the SecretKey created by the CLOVA Chatbot domain builder.

  • Sign content: it means the request body string.

• X-NCP-CHATBOT_SIGNATURE: X-NCP-CHATBOT_SIGNATURE is a message that sends a request to the chatbot.
  That is, when a request is sent to the chatbot, the request header requires content-type, X-NCP-CHATBOT_SIGNATURE, and
  X-NCP-CHATBOT_SIGNATURE is set by encoding the sign content (request body) in Base64.

Sample code for creating the Signature (Sign content) for each language

It describes in detail the X-NCP-CHATBOT_SIGNATURE setting and example.

• js code sample

const HmacSHA256 = require('crypto-js/hmac-sha256');
const EncBase64 = require('crypto-js/enc-base64');
signatureHeader = HmacSHA256(requestBodyString, secretKey).toString(EncBase64);

• java code sample

byte[] secretKeyBytes = secretKey.getBytes(StandardCharsets.UTF_8);
SecretKeySpec secretKeySpec = new SecretKeySpec(secretKeyBytes, "HmacSHA256");
Mac mac = Mac.getInstance("HmacSHA256");
mac.init(secretKeySpec);
byte[] signature = mac.doFinal(body.getBytes(StandardCharsets.UTF_8));
String signatureHeader = Base64.getEncoder().encodeToString(signature);

Request body

Open

• Response to welcome message

• trigger when open messenger, will response welcome message if have set in "Messenger Connection" -> "Custom"

Open request field details

Send

Sends a user’s question to CLOVA Chatbot.

When invoking send, the userId value can be set to anything as long as it is a unique key value. (e.g., member number)

• userid: unique key value, description: user query

Send request field details

getPersistentMenu

Calls persistent menu list.

if need show persistent menu but local cache not exists, could request PersistentMenu, will response persistentMenu field if fixed menu have set in messengers custom tab.

PersistentMenu can be requested if a persistent menu needs to be displayed but no local cache exists. Responds to the persistMenu field if persistent. The menu is set in the messenger customization tab.

getPersistentMenu request field details

Responses

Response result status (success/failure)

Success

• HTTP Status Code returns 200 if a chatbot query is successful, and the response fields are as follows:

Response result status field details (Success)

Error

Error

• HTTP Status Code returns 500 if a chatbot query fails, and the response fields are as follows

(Errors other than 500 are detailed at the bottom of the article):

Error Response Body:

{
    "code": "500",
    "message": "Internal server error",
    "timestamp": 12345678
}

Component

The chatbot’s response component follows the following json structure:

{
  "type": "...",
  "title": "optional, short bold text",
  "subTitle": "optional, short gray text",
  "data" : {
    ...
  }
}

There are three types of components:

• Basic Component
• Composite Component
• Flex Component

Basic Component

Three basic components are provided: text, image, and button.

Text

Text-type chatbot response component. Title, subtitle, detailed description, and URL can be set.

• Text component structure

• Text component JSON

• Detailed description of text component

Image

Image-type chatbot response component. Title, subtitle, detailed description, and URL can be set along with the image.

• Image component structure

• Image component Json

• Detailed description of image component

Button

Image-type chatbot response component. Title, subtitle, detailed description, and URL can be set along with the image.

• Button component structure

• Button component JSON

• Detailed description of button component

Composite Component

A composite component consists of template and carousel components.

The chatbot response can be set in Chatbot Builder according to specific characteristics. The response result set via Chatbot Builder is returned in the following JSON format:

Template Component

The template consists of basic building blocks. The template has three parts: cover, contentTable, and footTable. The cover is the main content. contentTable and footTable are table layouts.

• Template component structure

• Template component Json

• Template component details

• Table layout details

Carousel Component

You can set carousel responses.

• Carousel component JSON

• Carousel component details

Flex Component

Supports all Json object formats. JSON specifications can be defined as needed.

Example: FlexMessageContainerObject JSON can be used.

• Json in Flex

• Flex Component Details

Special Messenger Component

1. LineFlex

   The LineFlex function supported in Line messenger has been changed to a common Flex component format, but the specifications remain the same.

2. LineSticker

   The LineSticker function supported in LINE messenger can set sticker messages according to the sticker list format.

   • LineSticker Json

• LineSticker component details

3. LineWorksSticker

   The LineWorksSticker function supported in LINE WORKS can set sticker messages according to the corresponding format of the sticker list.

   • LineWorksSticker Json

• LineWorksSticker component details

Action

An action is common data for all components. When a component is clicked, it defines the operation to be performed.

• Postback

  Clicking on the component will postback the postbackText to the chatbot and display the postback as user chat.

  • Postback Json

• Postback component details

• Utterance

  Clicking on the building block will postback the text to the chatbot and display the text as the user’s chat.

  • Utterance Json

• Utterance component details

• Link

  Clicking the component will redirect the user to the URL.

  • Link Json

• Link component details

• Phone

  Clicking the component will redirect the user to the dial page. This function is only supported on mobile devices.

  • Phone Component JSON

• Phone component details

• Welcome

  Clicking the component will send an open event.

  • Welcome component Json

• Welcome component details

Quick Button

Group-pinning button at the bottom of the chat window.

Persistent Menu

The persistent menu is displayed when the user touches the menu button in the chat bar. It is always included in the welcome response. permanentMenu contents are included in responses without changes to utils.

Persistent menu is a Template Component , with these definition:

• title will show on the chat bar.
• no cover, cover should be discard.
• no foot table, fields relate to foot area should be discard.
• contentBackgroundImage is the background, if the components in the contentTable have image, will cover the background.

Errors

An explanation of error responses.

• Error Response Body:

 {
    "code": "1001",
    "message": "domain code test not found",
    "timestamp": 12345678
  }

• Body Introduce

• Errors

API examples

The following are example implementations of the CLOVA Custom API for each language:

• JAVA - Chatbot Custom API call source

package com.ncp.ai.demo.process;

import android.media.MediaPlayer;
import android.os.Environment;
import android.util.Base64;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.security.Timestamp;
import java.util.Date;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import android.util.Base64;

import org.json.JSONArray;
import org.json.JSONObject;

public class ChatbotProc {

  public static String main(String voiceMessage, String apiURL, String secretKey) {


        String chatbotMessage = "";

        try {
            //String apiURL = "https://ex9av8bv0e.apigw.ntruss.com/custom_chatbot/prod/";

            URL url = new URL(apiURL);

            String message = getReqMessage(voiceMessage);
            System.out.println("##" + message);

            String encodeBase64String = makeSignature(message, secretKey);

            HttpURLConnection con = (HttpURLConnection)url.openConnection();
            con.setRequestMethod("POST");
            con.setRequestProperty("Content-Type", "application/json;UTF-8");
            con.setRequestProperty("X-NCP-CHATBOT_SIGNATURE", encodeBase64String);

            // post request
            con.setDoOutput(true);
            DataOutputStream wr = new DataOutputStream(con.getOutputStream());
            wr.write(message.getBytes("UTF-8"));
            wr.flush();
            wr.close();
            int responseCode = con.getResponseCode();

            BufferedReader br;

            if(responseCode==200) { // Normal call
                System.out.println(con.getResponseMessage());

                BufferedReader in = new BufferedReader(
                        new InputStreamReader(
                                con.getInputStream()));
                String decodedString;
                while ((decodedString = in.readLine()) != null) {
                    chatbotMessage = decodedString;
                }
                //chatbotMessage = decodedString;
                in.close();

            } else {  // Error occurred
                chatbotMessage = con.getResponseMessage();
            }
        } catch (Exception e) {
            System.out.println(e);
        }

        return chatbotMessage;
    }

    public static String makeSignature(String message, String secretKey) {

        String encodeBase64String = "";

        try {
            byte[] secrete_key_bytes = secretKey.getBytes("UTF-8");

            SecretKeySpec signingKey = new SecretKeySpec(secrete_key_bytes, "HmacSHA256");
            Mac mac = Mac.getInstance("HmacSHA256");
            mac.init(signingKey);

            byte[] rawHmac = mac.doFinal(message.getBytes("UTF-8"));
            encodeBase64String = Base64.encodeToString(rawHmac, Base64.NO_WRAP);

            return encodeBase64String;

        } catch (Exception e){
            System.out.println(e);
        }

        return encodeBase64String;

    }

    public static String getReqMessage(String voiceMessage) {

        String requestBody = "";

        try {

            JSONObject obj = new JSONObject();

            long timestamp = new Date().getTime();

            System.out.println("##"+timestamp);

            obj.put("version", "v2");
            obj.put("userId", "U47b00b58c90f8e47428af8b7bddc1231heo2");
//=> userId is a unique code for each chat user, not a fixed value, recommend use UUID. use different id for each user could help you to split chat history for users.

            obj.put("timestamp", timestamp);

            JSONObject bubbles_obj = new JSONObject();

            bubbles_obj.put("type", "text");

            JSONObject data_obj = new JSONObject();
            data_obj.put("description", voiceMessage);

            bubbles_obj.put("type", "text");
            bubbles_obj.put("data", data_obj);

            JSONArray bubbles_array = new JSONArray();
            bubbles_array.put(bubbles_obj);

            obj.put("bubbles", bubbles_array);
            obj.put("event", "send");

            requestBody = obj.toString();

        } catch (Exception e){
            System.out.println("## Exception : " + e);
        }

        return requestBody;

    }
}

• Example of calling ChatbotProc.java above in UI stage

package com.example.user.ncpaidemo;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.speech.tts.Voice;
import android.util.Log;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.naver.speech.clientapi.SpeechRecognitionResult;
import com.ncp.ai.demo.process.ChatbotProc;
import com.ncp.ai.demo.process.CsrProc;
import com.ncp.ai.demo.process.CssProc;
import com.ncp.ai.utils.AudioWriterPCM;

import org.json.JSONArray;
import org.json.JSONObject;

import java.lang.ref.WeakReference;
import java.util.List;

public class VoiceChatbotActivity extends BaseActivity {

    private static final String TAG = VoiceChatbotActivity.class.getSimpleName();
    private RecognitionHandler handler;
    private CsrProc naverRecognizer;
    private TextView txtResult;
    private Button btnStart;
    private String mResult;
    private AudioWriterPCM writer;
    private String clientId;
    private String clientSecret;
    // Handle speech recognition Messages.
    private void handleMessage(Message msg) {
        switch (msg.what) {
            case R.id.clientReady: // Voice recognition ready
                txtResult.setText("Connected");
                writer = new AudioWriterPCM(Environment.getExternalStorageDirectory().getAbsolutePath() + "/NaverSpeechTest");
                writer.open("Test");
                break;
            case R.id.audioRecording:
                writer.write((short[]) msg.obj);
                break;
            case R.id.partialResult:
                mResult = (String) (msg.obj);
                mResult += mResult;
                txtResult.setText(mResult);
                break;
            case R.id.finalResult: // Final recognition result
                SpeechRecognitionResult speechRecognitionResult1 = (SpeechRecognitionResult) msg.obj;
                List<String> results1 = speechRecognitionResult1.getResults();
                StringBuilder strBuf1 = new StringBuilder();
                for(String result : results1) {
                    strBuf1.append(result);
                    //strBuf.append("\n");
                    break;
                }
                mResult = strBuf1.toString();
                txtResult.setText(mResult);

                requestChatbot();

                break;
            case R.id.recognitionError:
                if (writer != null) {
                    writer.close();
                }
                mResult = "Error code : " + msg.obj.toString();
                txtResult.setText(mResult);
                btnStart.setText(R.string.str_start);
                btnStart.setEnabled(true);
                break;
            case R.id.clientInactive:
                if (writer != null) {
                    writer.close();
                }
                btnStart.setText(R.string.str_start);
                btnStart.setEnabled(true);
                break;
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_voice_chatbot);
        SharedPreferences sharedPref = getSharedPreferences("PREF", Context.MODE_PRIVATE);

        clientId = sharedPref.getString("application_client_id", "");
        clientSecret = sharedPref.getString("application_client_secret", "");

        txtResult = (TextView) findViewById(R.id.textViewVoiceChatbotResult);
        btnStart = (Button) findViewById(R.id.btn_voice_chatbot1);
        handler = new RecognitionHandler(this);
        //naverRecognizer = new CsrProc(this, handler, clientId);
        naverRecognizer = CsrProc.getCsrProc(this, clientId);
        naverRecognizer.setHandler(handler);
        btnStart.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                if (!naverRecognizer.getSpeechRecognizer().isRunning()) {

                    mResult = "";
                    txtResult.setText("Connecting...");
                    btnStart.setText(R.string.str_stop);
                    naverRecognizer.recognize();
                } else {
                    Log.d(TAG, "stop and wait Final Result");
                    btnStart.setEnabled(false);
                    naverRecognizer.getSpeechRecognizer().stop();
                }
            }
        });

        Button voiceChatbotReplay;

        voiceChatbotReplay = (Button) findViewById(R.id.btn_voice_chatbot_replay);
        voiceChatbotReplay.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                TextView txtResult = (TextView) findViewById(R.id.text_voice_chatbot_replay);
                CSSExecute(txtResult.getText().toString());

            }
        });
    }

    private void requestChatbot() {

        SharedPreferences sharedPref = getSharedPreferences("PREF", Context.MODE_PRIVATE);

        String chatbotApiGwUrl = sharedPref.getString("chatbot_api_gw_url", "");
        String chatbotSecretKey = sharedPref.getString("chatbot_secret_key", "");

        TextView csrSourceText = (TextView)findViewById(R.id.textViewVoiceChatbotResult);
        String text = csrSourceText.getText().toString();

        VoiceChatbotActivity.VoiceChatbotTask task = new VoiceChatbotActivity.VoiceChatbotTask();
        task.execute(text, chatbotApiGwUrl, chatbotSecretKey);
    }

    @Override
    protected void onStart() {
        super.onStart(); // Voice recognition server initialization is here
        naverRecognizer.getSpeechRecognizer().initialize();
    }
    @Override
    protected void onResume() {
        super.onResume();
        mResult = "";
        txtResult.setText("");
        btnStart.setText(R.string.str_start);
        btnStart.setEnabled(true);
    }
//    @Override
//    protected void onStop() {
//        System.out.println("voice chatbot End!!!");
//        super.onStop(); // terminate voice recognition server
//        naverRecognizer.getSpeechRecognizer().release();
//    }
    // Declare handler for handling SpeechRecognizer thread's Messages.
    static class RecognitionHandler extends Handler {
        private final WeakReference<VoiceChatbotActivity> mActivity;
        RecognitionHandler(VoiceChatbotActivity activity) {
            mActivity = new WeakReference<VoiceChatbotActivity>(activity);
        }
        @Override
        public void handleMessage(Message msg) {
            VoiceChatbotActivity activity = mActivity.get();
            if (activity != null) {
                activity.handleMessage(msg);
            }
        }
    }

    public class VoiceChatbotTask extends AsyncTask<String, String, String> {

        @Override
        public String doInBackground(String... strings) {

            return ChatbotProc.main(strings[0], strings[1], strings[2]);
        }

        @Override
        protected void onPostExecute(String result) {

            ReturnThreadResult(result);
        }
    }

    public String ReturnThreadResult(String result) {

        //{"version":"v2","userId":"U47b00b58c90f8e47428af8b7bddc1231heo2","sessionId":"617666","timestamp":1546593912020,
        // "bubbles":[{"type":"template","data":{"cover":{"type":"text","data":{"description":"b"}},"contentTable":[[{"rowSpan":1,"colSpan":1,"data":{"type":"button","title":"b","data":{"type":"basic","action":{"type":"link","data":{"url":"https://www.ncloud.com/product"}}}}}],[{"rowSpan":1,"colSpan":1,"data":{"type":"button","title": "b","data":{"type":"basic","action":{"type":"link","data":{"url":"https://www.ncloud.com/product"}}}}}]]}}],"event":"send"}

        //{"version":"v2","userId":"U47b00b58c90f8e47428af8b7bddc1231heo2","sessionId":"641799","timestamp":1546777198124,
        // "bubbles":[{"type":"text","data":{"description":"b"}}],"event":"send"}
        String chatbotMessage =  "";
        String rlt = result;
        try{
            JSONObject jsonObject = new JSONObject(rlt);
            JSONArray bubbles = jsonObject.getJSONArray("bubbles");

            for (int i =0; i < bubbles.length(); i++){

                JSONObject bubble = bubbles.getJSONObject(i);

                String chatType = bubble.getString("type");

                if (chatType.equals("text")){

                    chatbotMessage = bubble.getJSONObject("data").getString("description");

                }else if (chatType.equals("template")) {

                    chatbotMessage = bubble.getJSONObject("data").getJSONObject("cover").getJSONObject("data").getString("description");

                }else {
                    chatbotMessage = "";
                }

                TextView txtResult = (TextView) findViewById(R.id.text_voice_chatbot_replay);
                txtResult.setText(chatbotMessage);

                break;
            }

        } catch (Exception e) {
            System.out.println(e);
        }

        CSSExecute(chatbotMessage);

        return chatbotMessage;
    }

    private void CSSExecute(String message) {

        VoiceChatbotActivity.NaverTTSTask tts = new VoiceChatbotActivity.NaverTTSTask();
        tts.execute(message, "mijin", clientId, clientSecret);
    }

    public class NaverTTSTask extends AsyncTask<String, String, String> {

        @Override
        public String doInBackground(String... strings) {
            System.out.println(strings[1]);
            CssProc.main(strings[0], strings[1], strings[2], strings[3]);
            return null;
        }
    }
}

• Python - CLOVA Chatbot Custom API v2

import hashlib
import hmac
import base64
import time
import requests
import json


class ChatbotMessageSender:

    # chatbot api gateway url
    ep_path = ''
    # chatbot custom secret key
    secret_key = ''

    def req_message_send(self):

        timestamp = self.get_timestamp()
        request_body = {
            'version': 'v2',
            'userId': 'U47b00b58c90f8e47428af8b7bddcda3d1111111',
            'timestamp': timestamp,
            'bubbles': [
                {
                    'type': 'text',
                    'data': {
                        'description': 'About Me'
                    }
                }
            ],
            'event': 'send'
        }

        ## Request body
        encode_request_body = json.dumps(request_body).encode('UTF-8')

        ## make signature
        signature = self.make_signature(self.secret_key, encode_request_body)

        ## headers
        custom_headers = {
            'Content-Type': 'application/json;UTF-8',
            'X-NCP-CHATBOT_SIGNATURE': signature
        }

        print("## Timestamp : ", timestamp)
        print("## Signature : ", signature)
        print("## headers ", custom_headers)
        print("## Request Body : ", encode_request_body)

        ## POST Request
        response = requests.post(headers=custom_headers, url=self.ep_path, data=encode_request_body)

        return response

    @staticmethod
    def get_timestamp():
        timestamp = int(time.time() * 1000)
        return timestamp

    @staticmethod
    def make_signature(secret_key, request_body):

        secret_key_bytes = bytes(secret_key, 'UTF-8')

        signing_key = base64.b64encode(hmac.new(secret_key_bytes, request_body, digestmod=hashlib.sha256).digest())

        return signing_key


if __name__ == '__main__':

    res = ChatbotMessageSender().req_message_send()

    print(res.status_code)
    if(res.status_code == 200):
        print(res.text)
        #print(res.read().decode("UTF-8"))

• php

function makeSignature($secretKey, $requestBody) {
  $signautue = base64_encode(hash_hmac('sha256', $requestBody, $secretKey,true));
  //echo "this is signiture : ".$signautue."\n";
  return $signautue;
}


try {
  // User IP
  if (isset($_SERVER['HTTP_X_FORWARDED_FOR']) && $_SERVER['HTTP_X_FORWARDED_FOR']) {
      $clientIpAddress = $_SERVER['HTTP_X_FORWARDED_FOR'];
  } else {
      $clientIpAddress = $_SERVER['HTTP_X_FORWARDED_FOR'];
  }


  $timestamp = "";
  $microtime = "";
  list($microtime,$timestamp) = explode(' ',microtime());
  $timestamp = $timestamp.substr($microtime, 2, 3);

  $url = "https://xi3mfpym2x.apigw.ntruss.com/send/beta/";

  $requestBody=  '{
    "version": "v2",
    "userId": "U47b00b58c90f8e47428af8b7bddcda3d231",
    "userIp": "'.$clientIpAddress.'",
    "timestamp": '.$timestamp.',
    "bubbles": [
      {
        "type": "text",
        "data" : {
          "description" : "postback text of welcome action"
        }
      }
    ],
    "event": "open"
  }';

  $secretKey = "YnVFTWZDemt3bUZhaEJlalN1Z3ZNY2pzeVp0aVRjd04=12";
  $signautue = makeSignature($secretKey,$requestBody);

  $is_post = true;

  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_POST, true);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
  curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
  curl_setopt($ch, CURLOPT_POSTFIELDS, $requestBody);
  $headers = array();
  $headers[] = "Content-Type:application/json; charset=utf-8";
  $headers[] = "X-NCP-CHATBOT_SIGNATURE: " .$signautue;
  curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

  $response = curl_exec($ch);
  $err = curl_error($ch);
  curl_close ($ch);
  if ($err) {
    echo "cURL Error #:" . $err;
  } else {
    echo $response;
  }

} catch(Exception $E) {
    echo "Response: ". $E->lastResponse . "\n";
}
?>

• swift

import UIKit
import CommonCrypto


// chatbot custom secret key
let secret_key = "";

// chatbot api gateway url
let invoke_url = "";

class ViewController: UIViewController, URLSessionDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        demo()
    }

    func demo() {
        let timeInterval: TimeInterval = NSDate().timeIntervalSince1970
        let millisecond = CLongLong(round(timeInterval*1000))
        
        let body = ["bubbles":[["data": ["description":"test"],
                                "type":"text"]],
                    "event":"send",
                    "timestamp":millisecond,
                    "userId":"test",
                    "version":"v2"] as NSDictionary
       
        do {
            let jsonDataFromBody = try JSONSerialization.data(withJSONObject: body, options: JSONSerialization.WritingOptions.prettyPrinted)
            let jsonBytes = [CUnsignedChar](jsonDataFromBody)
            let jsonBytesPointer = UnsafePointer<CUnsignedChar>(jsonBytes) //UnsafeRawPointer
            
            let cKey = secret_key.cString(using: String.Encoding.utf8)
            let digestLen = Int(CC_SHA256_DIGEST_LENGTH)
            let sha256 = UnsafeMutablePointer<CUnsignedChar>.allocate(capacity: digestLen)
            CCHmac(CCHmacAlgorithm(kCCHmacAlgSHA256), cKey, secret_key.lengthOfBytes(using: String.Encoding.utf8), jsonBytesPointer, jsonBytes.count, sha256)
            
            let base64_sha256 = Data.init(bytes: sha256, count: Int(CC_SHA256_DIGEST_LENGTH)).base64EncodedString()
            
            httpsRequest("X-NCP-CHATBOT_SIGNATURE", base64_sha256, body: jsonDataFromBody)
            sha256.deallocate()
            
        } catch {
            print(error)
        }
        
    }
    
    func httpsRequest(_ signHeaderKey:String, _ signature:String, body:Data) {
        let url = URL.init(string: invoke_url)!
        var request = URLRequest.init(url: url)
        request.addValue(signature, forHTTPHeaderField: signHeaderKey)
        request.addValue("application/json", forHTTPHeaderField: "Content-Type")
        request.httpMethod = "POST"
        request.httpBody = body
     
        let session = URLSession.shared
        let task = session.dataTask(with: request) { (data:Data?, response:URLResponse?, error:Error?) in
            print(String.init(data:data!, encoding: .utf8)!)
        }
        task.resume()
    }
    
    func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        if challenge.protectionSpace.authenticationMethod != NSURLAuthenticationMethodServerTrust {
            return
        }
        let credential = URLCredential.init(trust: challenge.protectionSpace.serverTrust!)
        completionHandler(URLSession.AuthChallengeDisposition.useCredential, credential)
    }

}

• objective-c

#import "ViewController.h"
#import <UIKit/UIKit.h>
#import <CommonCrypto/CommonHMAC.h>

// chatbot custom secret key
static NSString *secret_key = @"";

// chatbot api gateway url
static NSString *invoke_url = @"";

@interface ViewController () <NSURLSessionDelegate>

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self demo];
}

- (void)demo {
    NSTimeInterval time = [[NSDate date] timeIntervalSince1970]*1000;
    long long millisecond = [[NSNumber numberWithDouble:time] longLongValue];
    NSDictionary *body = @{@"bubbles":@[@{@"data":@{@"description":@"test"},
                                          @"type":@"text"}],
                           @"event":@"send",
                           @"timestamp":millisecond,
                           @"userId":@"U47b00b58c90f8e47428af8b7bddcda3d1111111",
                           @"version":@"v2"
                           };
    NSError *error;

    NSData *jsondataFrombody = [NSJSONSerialization dataWithJSONObject:body
                                                           options:0
                                                             error:&error];
    
    const char *cKey = [secret_key cStringUsingEncoding:NSUTF8StringEncoding];
    NSMutableData* sha256 = [NSMutableData dataWithLength:CC_SHA256_DIGEST_LENGTH];
    CCHmac(kCCHmacAlgSHA256, cKey, secret_key.length, jsondataFrombody.bytes, jsondataFrombody.length, sha256.mutableBytes);
    
    NSString *base64_sha256 = [sha256 base64EncodedStringWithOptions:0];
    
    [self httpsRequest:@"X-NCP-CHATBOT_SIGNATURE" signature:base64_sha256 bodyData:jsondataFrombody];
}

- (void)httpsRequest:(NSString *)signHeaderKey signature:(NSString *)sign bodyData:(NSData *)bodyData  {
    NSURL *url = [NSURL URLWithString:invoke_url];
    NSMutableURLRequest *mRequest = [NSMutableURLRequest requestWithURL:url];
    [mRequest setValue:sign forHTTPHeaderField:signHeaderKey];
    [mRequest setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
    mRequest.HTTPMethod = @"POST";
    mRequest.HTTPBody = bodyData;
    
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]
                                                          delegate:self
                                                     delegateQueue:[NSOperationQueue mainQueue]];//replace delegateQueue with your workingQueue
    NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:mRequest completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        NSLog(@"response: %@", [response description]);
        NSLog(@"response data:%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
    }];
    [dataTask resume];

}

- (void)URLSession:(NSURLSession *)session didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition, NSURLCredential * _Nullable))completionHandler {
    if (![challenge.protectionSpace.authenticationMethod isEqualToString:@"NSURLAuthenticationMethodServerTrust"]) {
        return;
    }
    NSURLCredential *credential = [[NSURLCredential alloc] initWithTrust:challenge.protectionSpace.serverTrust];
    completionHandler(NSURLSessionAuthChallengeUseCredential,credential);

}

@end