Google OAuth Setup Guide

This guide will help you set up Google OAuth authentication for Bitinfrashop.

🔧 Step 1: Google Cloud Console Setup

1.1 Create a Google Cloud Project

1. Go to Google Cloud Console
2. Click "Select a project" → "New Project"
3. Enter project name: Bitinfrashop (or your preferred name)
4. Click "Create"

1.2 Enable Google+ API

1. In the Google Cloud Console, go to "APIs & Services" → "Library"
2. Search for "Google+ API" or "Google Identity"
3. Click on "Google+ API" and click "Enable"

1.3 Create OAuth 2.0 Credentials

1. Go to "APIs & Services" → "Credentials"
2. Click "Create Credentials" → "OAuth 2.0 Client IDs"
3. If prompted, configure the OAuth consent screen:
   • Choose "External" user type
   • Fill in required fields:
     • App name: Bitinfrashop
     • User support email: Your email
     • Developer contact: Your email
   • Add scopes: email, profile, openid
   • Add test users (your email address)

1.4 Configure OAuth Client

1. Application type: "Web application"
2. Name: Bitinfrashop Web Client
3. Authorized redirect URIs:
   • For development: http://localhost:3000/api/auth/callback/google
   • For production: https://yourdomain.com/api/auth/callback/google
4. Click "Create"

1.5 Get Credentials

1. Copy the Client ID and Client Secret
2. Keep these secure - you'll need them for environment variables

🔐 Step 2: Environment Configuration

2.1 Update .env.local

Add the following to your .env.local file:

# NextAuth.js Configuration
NEXTAUTH_SECRET=your_nextauth_secret_here
NEXTAUTH_URL=http://localhost:3000

# Google OAuth Configuration
GOOGLE_CLIENT_ID=your_google_client_id_here
GOOGLE_CLIENT_SECRET=your_google_client_secret_here

2.2 Generate NextAuth Secret

Generate a secure secret for NextAuth:

# Option 1: Using Node.js
node -e "console.log(require('crypto').randomBytes(32).toString('hex'))"

# Option 2: Using OpenSSL
openssl rand -hex 32

# Option 3: Online generator
# Visit: https://generate-secret.vercel.app/32

🚀 Step 3: Test the Setup

3.1 Start the Development Server

npm run dev

3.2 Test Google Login

1. Go to http://localhost:3000/login
2. Click "Continue with Google"
3. Complete the Google OAuth flow
4. You should be redirected back to the dashboard

🔒 Step 4: Production Deployment

4.1 Update OAuth Settings

1. Go back to Google Cloud Console → "Credentials"
2. Edit your OAuth 2.0 Client ID
3. Add production redirect URI: https://yourdomain.com/api/auth/callback/google
4. Update authorized domains if needed

4.2 Environment Variables

Update your production environment variables:

NEXTAUTH_URL=https://yourdomain.com
GOOGLE_CLIENT_ID=your_production_client_id
GOOGLE_CLIENT_SECRET=your_production_client_secret
NEXTAUTH_SECRET=your_production_secret

🛠️ Troubleshooting

Common Issues

1. "Error 400: redirect_uri_mismatch"

• Cause: Redirect URI doesn't match what's configured in Google Console
• Solution: Ensure redirect URI in Google Console exactly matches your domain

2. "Access blocked: This app's request is invalid"

• Cause: OAuth consent screen not properly configured
• Solution: Complete the OAuth consent screen setup in Google Console

3. "Invalid client" error

• Cause: Wrong Client ID or Client Secret
• Solution: Double-check environment variables match Google Console

4. Database errors after Google login

• Cause: Database schema not updated
• Solution: Run npx prisma db push to apply schema changes

Debug Mode

Enable debug mode in development:

NEXTAUTH_DEBUG=true

📚 Additional Resources

• NextAuth.js Documentation
• Google OAuth 2.0 Documentation
• Google Cloud Console

🔐 Security Notes

1. Never commit .env.local or .env files to version control
2. Use different credentials for development and production
3. Rotate secrets regularly in production
4. Monitor OAuth usage in Google Cloud Console
5. Use HTTPS in production (required by Google OAuth)

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Need help? Contact: nodediver@proton.me