Google

# Google OAuth 2.0 / OIDC + Gmail, Calendar & Drive Emulator

OAuth 2.0 and OpenID Connect emulation with authorization code flow, PKCE support, ID tokens, OIDC discovery, refresh tokens, plus Gmail, Google Calendar, and Google Drive REST API surfaces.

## Start

```bash
# Google only
npx emulate --service google

# Default port
# http://localhost:4002
```

Or programmatically:

```typescript
import { createEmulator } from 'emulate'

const google = await createEmulator({ service: 'google', port: 4002 })
// google.url === 'http://localhost:4002'
```

## Pointing Your App at the Emulator

### Environment Variable

```bash
GOOGLE_EMULATOR_URL=http://localhost:4002
```

### OAuth URL Mapping

| Real Google URL | Emulator URL |
|-----------------|-------------|
| `https://accounts.google.com/o/oauth2/v2/auth` | `$GOOGLE_EMULATOR_URL/o/oauth2/v2/auth` |
| `https://oauth2.googleapis.com/token` | `$GOOGLE_EMULATOR_URL/oauth2/token` |
| `https://www.googleapis.com/oauth2/v2/userinfo` | `$GOOGLE_EMULATOR_URL/oauth2/v2/userinfo` |
| `https://accounts.google.com/.well-known/openid-configuration` | `$GOOGLE_EMULATOR_URL/.well-known/openid-configuration` |
| `https://www.googleapis.com/oauth2/v3/certs` | `$GOOGLE_EMULATOR_URL/oauth2/v3/certs` |
| `https://gmail.googleapis.com/gmail/v1/...` | `$GOOGLE_EMULATOR_URL/gmail/v1/...` |
| `https://www.googleapis.com/calendar/v3/...` | `$GOOGLE_EMULATOR_URL/calendar/v3/...` |
| `https://www.googleapis.com/drive/v3/...` | `$GOOGLE_EMULATOR_URL/drive/v3/...` |

### google-auth-library (Node.js)

```typescript
import { OAuth2Client } from 'google-auth-library'

const GOOGLE_URL = process.env.GOOGLE_EMULATOR_URL ?? 'https://accounts.google.com'

const client = new OAuth2Client({
  clientId: process.env.GOOGLE_CLIENT_ID,
  clientSecret: process.env.GOOGLE_CLIENT_SECRET,
  redirectUri: 'http://localhost:3000/api/auth/callback/google',
})

const emulatorAuthorizeUrl = `${GOOGLE_URL}/o/oauth2/v2/auth?client_id=${process.env.GOOGLE_CLIENT_ID}&redirect_uri=...&scope=openid+email+profile&response_type=code&state=...`
```

### Auth.js / NextAuth.js

```typescript
import Google from '@auth/core/providers/google'

Google({
  clientId: process.env.GOOGLE_CLIENT_ID,
  clientSecret: process.env.GOOGLE_CLIENT_SECRET,
  authorization: {
    url: `${process.env.GOOGLE_EMULATOR_URL}/o/oauth2/v2/auth`,
    params: { scope: 'openid email profile' },
  },
  token: {
    url: `${process.env.GOOGLE_EMULATOR_URL}/oauth2/token`,
  },
  userinfo: {
    url: `${process.env.GOOGLE_EMULATOR_URL}/oauth2/v2/userinfo`,
  },
})
```

### Passport.js

```typescript
import { Strategy as GoogleStrategy } from 'passport-google-oauth20'

const GOOGLE_URL = process.env.GOOGLE_EMULATOR_URL ?? 'https://accounts.google.com'

new GoogleStrategy({
  clientID: process.env.GOOGLE_CLIENT_ID,
  clientSecret: process.env.GOOGLE_CLIENT_SECRET,
  callbackURL: 'http://localhost:3000/api/auth/callback/google',
  authorizationURL: `${GOOGLE_URL}/o/oauth2/v2/auth`,
  tokenURL: `${GOOGLE_URL}/oauth2/token`,
  userProfileURL: `${GOOGLE_URL}/oauth2/v2/userinfo`,
}, verifyCallback)
```

## Seed Config

```yaml
google:
  users:
    - email: testuser@gmail.com
      name: Test User
      given_name: Test
      family_name: User
      picture: ht