Issue key

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

public class APIExamCaptchaNkey {

    public static void main(String[] args) {
        String clientId = "YOUR_CLIENT_ID";//Application's client ID value";
        String clientSecret = "YOUR_CLIENT_SECRET";//Application's client secret value";
        try {
            String code = "0"; // Set to 0 for key issuance and 1 for CAPTCHA image comparison
            String apiURL = "https://naveropenapi.apigw.ntruss.com/captcha/v1/nkey?code=" + code;
            URL url = new URL(apiURL);
            HttpURLConnection con = (HttpURLConnection)url.openConnection();
            con.setRequestMethod("GET");
            con.setRequestProperty("X-NCP-APIGW-API-KEY-ID", clientId);
            con.setRequestProperty("X-NCP-APIGW-API-KEY", clientSecret);
            int responseCode = con.getResponseCode();
            BufferedReader br;
            if(responseCode==200) { // Successful call
                br = new BufferedReader(new InputStreamReader(con.getInputStream()));
            } else {  // Error occurred
                br = new BufferedReader(new InputStreamReader(con.getErrorStream()));
            }
            String inputLine;
            StringBuffer response = new StringBuffer();
            while ((inputLine = br.readLine()) != null) {
                response.append(inputLine);
            }
            br.close();
            System.out.println(response.toString());
        } catch (Exception e) {
            System.out.println(e);
        }
    }
}

import os
import sys
import urllib.request
client_id = "YOUR_CLIENT_ID"
client_secret = "YOUR_CLIENT_SECRET"
code = "0"
url = "https://naveropenapi.apigw.ntruss.com/captcha/v1/nkey?code=" + code
request = urllib.request.Request(url)
request.add_header("X-NCP-APIGW-API-KEY-ID",client_id)
request.add_header("X-NCP-APIGW-API-KEY",client_secret)
response = urllib.request.urlopen(request)
rescode = response.getcode()
if(rescode==200):
    response_body = response.read()
    print(response_body.decode('utf-8'))
else:
    print("Error Code:" + rescode)

<?php
  $client_id = "YOUR_CLIENT_ID";
  $client_secret = "YOUR_CLIENT_SECRET";
  $code = "0";
  $url = "https://naveropenapi.apigw.ntruss.com/captcha/v1/nkey?code=".$code;
  $is_post = false;
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_POST, $is_post);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  $headers = array();
  $headers[] = "X-NCP-APIGW-API-KEY-ID: ".$client_id;
  $headers[] = "X-NCP-APIGW-API-KEY: ".$client_secret;
  curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
  $response = curl_exec ($ch);
  $status_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
  echo "status_code:".$status_code."<br />";
  curl_close ($ch);
  if($status_code == 200) {
    echo $response;
  } else {
    echo "Error content:".$response;
  }
?>

var express = require('express');
var app = express();
var client_id = 'YOUR_CLIENT_ID';
var client_secret = 'YOUR_CLIENT_SECRET';
var code = "0";
app.get('/captcha/nkey', function (req, res) {
   var api_url = 'https://naveropenapi.apigw.ntruss.com/captcha/v1/nkey?code=' + code;
   var request = require('request');
   var options = {
       url: api_url,
       headers: {'X-NCP-APIGW-API-KEY-ID':client_id, 'X-NCP-APIGW-API-KEY': client_secret}
    };
   request.get(options, function (error, response, body) {
     if (!error && response.statusCode == 200) {
       res.writeHead(200, {'Content-Type': 'text/json;charset=utf-8'});
       res.end(body);
     } else {
       res.status(response.statusCode).end();
       console.log('error = ' + response.statusCode);
     }
   });
 });
 app.listen(3000, function () {
   console.log('http://127.0.0.1:3000/captcha/nkey app listening on port 3000!');
 });

using System;
using System.Net;
using System.Text;
using System.IO;

namespace NaverAPI_Guide
{
    public class APIExamCaptchaNkey
    {
        static void Main(string[] args)
        {
            string code = "0"; // Set to 0 for key issuance and 1 for CAPTCHA image comparison
            string url = "https://naveropenapi.apigw.ntruss.com/captcha/v1/nkey?code=" + code;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Headers.Add("X-NCP-APIGW-API-KEY-ID", "YOUR-CLIENT-ID");
            request.Headers.Add("X-NCP-APIGW-API-KEY", "YOUR-CLIENT-SECRET");
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            string status = response.StatusCode.ToString();
            if(status == "OK")
            {
                Stream stream = response.GetResponseStream();
                StreamReader reader = new StreamReader(stream, Encoding.UTF8);
                string text = reader.ReadToEnd();
                Console.WriteLine(text);
            }
            else
            {
                Console.WriteLine("Error occurrence=" + status);
            }
        }
    }
}