
#### Table of Contents

1. Introduction
2. Requirements
3. Add Google Sign-In callback
4. Use with next-session
5. Conclusion

### Introduction

This tutorial shows how to integrate sign in with Google account, and how to handle callback response from Google Sign-In.

### Requirements

- GCP
  - Has knowledge of using Google Cloud.
  - Already setup google sign-in setting OAuth Client ID and Secret at Google Cloud, or reference [here](/blog/post/how-to-sign-in-with-google-for-web-application-about-setup) for how to setup Google Sign.

### Add Google Sign-In callback

Once setup the Google Sign-In, OAuth Client, and redirect URLs, then first thing we can do is add call back function at the application to handle the response sending by the Google Sign In.

If define as below as **_http://localhost:3000/api/auth/callback/google_**, then once user successfully sign-in with google will redirect to that URL with JWT token, so will need logic to process the information, for instance, save the **_name_**, **_email_** to the database, or save the email to the session. So this article will demonstrate how to use `next-session` to save to the session, cookie and how to clear session build custom logic with logout function.

![OAuth Create Screen](/images/sign-google-nextjs/img2.png)

Below is sample code, so once google callback come to this function, you can start parse the credential as **_jwt_** token, then read the value from, for instance below you should be able to get name and email who successfully sign-in with google.

```TypeScript
export default async function auth(req: NextApiRequest, res: NextApiResponse) {

const credential = req.body.credential;

const jwtToken = JSON.parse(Buffer.from(credential.split('.')[1], 'base64').toString())

const name = jwtToken.name;

const email = jwtToken.email;

}

```

### Use with next-session

Once build callback function, you need to store those information at the web application. One of the way to do is using the **_next-session_**.

```TypeScript
export const getSession = nextSession({
  cookie: {
    sameSite: 'lax',
    maxAge: 60 * 60 * 24 * 365,
  }
});
```

### Conclusion
This blog demo example code how to google sign-in callback works and how you can using ***next-session*** to store user specific information across your application.

This tutorial shows how to integrate sign in with Google account, and how to handle callback response from Google Sign-In.

Sign In with Google at Next.js and Next-Session


#### Table of Contents

1. Introduction
2. Requirements
3. Create Google OAuth Client ID and Secret
4. Configure OAuth Consent Screen
5. Load with Default Setting
6. Conclusion

### Introduction

This tutorial shows how to integrate sign in with Google, along with setup the Google API, Create OAuth Client.

### Requirements

- GCP
  - Has knowledge of using Google Cloud.
  - Has set up project by using Google Cloud.

### Create Google OAuth Client ID and Secret

Since use Google Account for sign in, first we'll need to create OAuth Client ID an Client Secret.

Go to the APIs & Services' Credentials Page
Once land at the Credentials Page, you'll see _APIKeys_, _OAuth 2.0 Client IDs_, _Service Accounts_.

Click _CREATE CREDENTIALS_ and choose _OAuth Client ID_.
![Choose Create OAuth](/images/sign-google-nextjs/img1.png)

For the detail of the OAuth Client ID, reference as below

- Application Type
  - Choose _Web Application_, since we'll use the _Next.js_.
- Name
  - Enter any meaningful name following your application's standard.
- Authorized Javascript Origins
  - _http://localhost:3000_, for testing, our next.js will start port as _3000_.
- Authorized redirect URIs
  - _http://localhost:3000/api/auth/callback/google_, this's the redirect URL after user authorized with Google Account, will redirect to this URL with.

![OAuth Create Screen](/images/sign-google-nextjs/img2.png)

Click the _Create_ button, once create the OAuth, we'll be able to obtain the Google client ID and secret, store these for now cause we'll need these value later.

### Configure OAuth Consent Screen

First of all, what's this OAuth Consent Screen, right?
So enter the information at OAuth Consent Screen, can control below options when user use Google Account to Sign In.

- Application Name
- Application Logo
- Support email
- Application HomePage / Privacy Policy / Terms of Service Links

As you can see, Enter detail information can help user to find more detail about the application during the sign-in process.

### Load with Default Setting

Once create OAuth Client ID, Secret and fill out OAuth Consent Screen, the Setting for the Google part is done, now, base on the Google Account's instruction, at very minimal with below information you can use the Google Account now.

First, add following script file to the page.

```Javascript
<script src="https://apis.google.com/js/platform.js" defer></script>
```

Then, create button with _OAuth Client ID_

```HTML
<div
  id="g_id_onload"
  data-client_id="{Your_OAuth_Client_ID}.apps.googleusercontent.com"
  data-context="signup"
  data-ux_mode="popup"
  data-login_uri="auth"
  data-auto_prompt="false"
>Sign In</div>
```

Now, with these setup, once launch the app with port _http://localhost:3000_ and click the button Sign In will open Google Account, and once finish the Google Account's authentication will redirect to your app's redirect URL and post the JWT token information.

You can enhance above code so you can use the Google Account Sign in, but at this tutorial we'd like also try the _next-auth.js_ for authentication.

### Conclusion

Sign In with Google is the quick way to let your user to authenticate to your application, without manage user's password, this blog is focus on how to setup the Google Sign-in at Google, next will demo how to use the same setting to create Google Sign-in with next-auth or build system your self to intergrade with Google Sign-in.


This tutorial shows how to integrate sign in with Google account, focus on how to setup at the GCP.

How to Configure Google Sign-In with Google


#### Table of Contents

1. Introduction
2. Requirements
3. Get started with NextAuth.js with Google Sign In
4. Conclusion

### Introduction

This tutorial shows how to integrate sign in with Google by use _next-auth.js_ under Next.js Web Application, for how to setup or configure google sign-in, please reference [here](/blog/post/how-to-sign-in-with-google-for-web-application-about-setup) for detail about setup google sign-in.

### Requirements

Since this tutorial assume we're use Google Account with _next-auth.js_ Next.js, so below are least requirements to get further of this tutorial.

- GCP
  - Has knowledge of using Google Cloud.
  - Has set up project by using Google Cloud.
- Next.js
  - Already has application built with _Next.js_.
  - Has knowledge of how to use _Next.js_.

### Client ID, Secret, OAuth Consent Screen Setup

Regarding Google OAuth Client ID and Secret, OAuth Consent Screen setup, please reference [here](/blog/post/how-to-sign-in-with-google-for-web-application-about-setup) to see more detail.

### Get started with NextAuth.js with Google Sign In

Here we'll setup NextAuth.js to the Next.js
First, let's install the dependencies packages.

```node.js
npm install next-auth
```

Next, let's replace `_app.js` with below code.

**Before**

```Javascript
export default function App({ Component, pageProps }) {
  return <Component {...pageProps} />;
}
```

**After**

```Javascript
import { SessionProvider } from 'next-auth/react';

export default function App({ Component, pageProps }) {
  return (
    <SessionProvider session={pageProps.session}>
      <Component {...pageProps} />
    </SessionProvider>
  );
}
```

Create **[...nextauth...].js** under **pages/api/auth** location.
_NextAuth.js_ has many different provider, Google Account is just one of them, replace the below client*id and client_secret with the one you already created at the OAuth. Also, \_NextAuth.js* has different callbacks, you can use one of this to intergrade with your own system, such as check the user if already register at your application or not.

```Javascript
import type { NextApiRequest, NextApiResponse } from 'next';
import NextAuth from 'next-auth';
import GoogleProvider from 'next-auth/providers/google';

export default async function auth(req: NextApiRequest, res: NextApiResponse) {
  return await NextAuth(req, res, {
    providers: [
      GoogleProvider({
        clientId:
          'my_client_id',
        clientSecret: 'my_client_secret',
      }),
    ],
    callbacks: {
      async jwt({ token, account, isNewUser, profile, user }) {
        return token;
      },
      async signIn({ user, account, profile, email, credentials }) {

        if (account.provider === 'google') {
          // check if user already exist or not with custom db

          else {
            // existing user
          }
        }
        return true;
      },
      async redirect({ url, baseUrl }) {
        return baseUrl;
      },
      async session({ session, token, user }) {
        return session;
      },
    },
    theme: {
      colorScheme: 'light',
      brandColor: '#343434',
      logo: '',
      buttonText: '#333',
    },
  });
}
```

### Conclusion

Sign In with Google is strict forward way to let your user to authenticate with your application, with `next-auth` is even better that due to it's able to manage the session and make it easy to manager the user information or intergrade with Google Sign-In and other third-party sign-in platform. Next, will be without using the `next-auth`, how to intergrade with Google Sign-in with Next.js web application.


This tutorial shows how to use Next-Auth to integrate sign in with Google under Next.js web application.

Category Google Sign In

Sign In with Google at Next.js and Next-Session

How to Configure Google Sign-In with Google

How to Use Next-Auth with Google Sign-In