Sign in with Google

OAuth 2.0 based Google login web authentication method. Compatible with both iOS and Android.

How It Works

Android:

1. Select Google account in external browser (or Chrome Custom Tabs)
2. Receive id_token via Deep Link
3. Call account registration (SocialSignIn) or member conversion (SocialChange) API with token

iOS:

1. Display in-app authentication session via ASWebAuthenticationSession
2. Receive id_token via OnGoogleAuthCallback method
3. Call account registration (SocialSignIn) or member conversion (SocialChange) API with token

Unity Implementation

using System;
using System.Collections;
using UnityEngine;
using UnityEngine.Networking;

public class GoogleSignin : MonoBehaviour
{
    private string HOST_PLAYNANOO_OAUTH2REDIRECT = "https://www.playnanoo.com/oauth2redirect.html";
    private string OAUTH2REDIRECT_SCOPE = "openid email profile";
    private string clientId = "Your Google Client Id";

    void Start()
    {
        Application.deepLinkActivated += OnDeepLink;
    }

    private void OnDeepLink(string url)
    {
        string token = ExtractIdToken(url);
        if (!string.IsNullOrEmpty(token))
        {
            SendTokenToServer(token);
        }
    }

    private string ExtractIdToken(string url)
    {
        // query parameter(?) 또는 fragment(#)에서 id_token 추출
        string paramString = null;

        if (url.Contains("?"))
        {
            paramString = url.Split('?')[1];
        }
        else if (url.Contains("#"))
        {
            paramString = url.Split('#')[1];
        }

        if (string.IsNullOrEmpty(paramString)) return null;

        string[] parts = paramString.Split('&');
        foreach (var p in parts)
        {
            if (p.StartsWith("id_token="))
                return p.Substring("id_token=".Length);
        }
        return null;
    }

    public void Sign_in_with_Google()
    {
        string nonce = Guid.NewGuid().ToString("N");

        string authUrl = "https://accounts.google.com/o/oauth2/v2/auth"
                        + "?client_id=" + clientId
                        + "&redirect_uri=" + HOST_PLAYNANOO_OAUTH2REDIRECT
                        + "&response_type=id_token"
                        + "&scope=" + Uri.EscapeDataString(OAUTH2REDIRECT_SCOPE)
                        + "&nonce=" + nonce
                        + "&prompt=select_account"
                        + "&login_hint=";  // 빈 값으로 자동 로그인 방지

        // 외부 브라우저에서 열기 (403 disallowed_useragent 방지)
        OpenURLInExternalBrowser(authUrl);
    }

    private void OpenURLInExternalBrowser(string url)
    {
        if (Application.platform == RuntimePlatform.Android)
        {
            try
            {
                using (AndroidJavaClass unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
                using (AndroidJavaObject currentActivity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity"))
                using (AndroidJavaObject intent = new AndroidJavaObject("android.content.Intent", "android.intent.action.VIEW"))
                using (AndroidJavaClass uri = new AndroidJavaClass("android.net.Uri"))
                {
                    intent.Call<AndroidJavaObject>("setData", uri.CallStatic<AndroidJavaObject>("parse", url));
                    intent.Call<AndroidJavaObject>("addFlags", 0x10000000); // FLAG_ACTIVITY_NEW_TASK
                    intent.Call<AndroidJavaObject>("addCategory", "android.intent.category.BROWSABLE");

                    try
                    {
                        intent.Call<AndroidJavaObject>("setPackage", "com.android.chrome");
                        currentActivity.Call("startActivity", intent);
                    }
                    catch
                    {
                        intent.Call<AndroidJavaObject>("setPackage", null);
                        currentActivity.Call("startActivity", intent);
                    }
                }
            }
            catch
            {
                Application.OpenURL(url);
            }
        }
        else
        {
            Application.OpenURL(url);
        }
    }

    //인증 완료 시 토큰 받는 메소드.
    private void SendTokenToServer(string token)
    {
        //toten 값으로 SocialChange 또는 SocialSignIn 진행.
        //SocialChange(token, PN_ACCOUNT_GOOGLE);
        // or
        //SocialSignIn(token, PN_ACCOUNT_GOOGLE);
    }

     //계정 전환 예시. SocialChange
    public void SocialChange(string token, string accountType)
    {
    }

    public void SocialSignIn(string token, string accountType)
    {
    }
}

OAuth 2.0 Parameters

Parameter	Value	Description
client_id	Issued from Google Cloud Console	OAuth web client ID
redirect_uri	https://www.playnanoo.com/oauth2redirect.html	Redirect URL after authentication
response_type	id_token	Request OpenID Connect ID token
scope	openid email profile	User information scope to request
nonce	Guid.NewGuid()	Random string to prevent replay attacks
prompt	select_account	Force account selection display

Environment Settings Required

Before using Sign in with Google, you must complete the following settings by referring to the Google Environment Settings documentation:

• Issue OAuth 2.0 client ID from Google Cloud Console
• Configure Android/iOS Deep Link
• Register redirect URI

How to Use

1. Start Google Login

Sign_in_with_Google();

An external browser opens and the user selects a Google account.

2. Link Account with Token

After authentication is complete, call the PlayNANOO API with the id_token received in the SendTokenToServer method:

New Login (SocialSignIn)

public void SocialSignIn(string token, string accountType)
{
    // 구글 계정으로 처음 로그인
    //accountType : PN_ACCOUNT_GOOGLE
}

Member Conversion (SocialChange)

public void SocialChange(string token, string accountType)
{
    // 비회원에서 구글 회원으로 전환
    //accountType : PN_ACCOUNT_GOOGLE
}

References

• Account Type Value: PN_ACCOUNT_GOOGLE = "GOOGLE" - For detailed information, see Etc > Account Type Information
• Member Conversion: See Guest Login > Member Conversion documentation

Platform-Specific Callback Handling

Android

• Receives callbacks via DeepLink.
• Register a callback method on the Application.deepLinkActivated event.
• If the Chrome Custom Tabs library is included, the browser opens in an in-app overlay form.
• If the library is not present, it opens in an external Chrome browser and returns to the app via deep link after authentication.

iOS

• Uses ASWebAuthenticationSession to open an authentication session within the app.
• Register a callback with SetGoogleAuthCallback and it will be called upon authentication completion.

void Start()
{
    Plugin plugin = Plugin.GetInstance();

    // iOS Google OAuth 콜백 등록
    plugin.SetGoogleAuthCallback((result) =>
    {
        if (result.StartsWith("error:"))
        {
            Debug.LogError("[GoogleOAuth] iOS Auth Error: " + result);
            return;
        }

        // result는 콜백 URL 전체 (예: {game_id}://#id_token=xxx&...)
        // ※ mygame:// scheme은 deprecated 되었습니다. PlayNANOO 콘솔에 등록된 Game ID를 scheme으로 사용합니다.
        string token = ExtractIdToken(result);
        if (!string.IsNullOrEmpty(token))
        {
            // 토큰으로 SocialSignIn 또는 SocialChange 호출
        }
    });
}

private string ExtractIdToken(string url)
{
    if (!url.Contains("#")) return null;
    string fragment = url.Split('#')[1];
    string[] parts = fragment.Split('&');
    foreach (var p in parts)
    {
        if (p.StartsWith("id_token="))
            return p.Substring("id_token=".Length);
    }
    return null;
}