"""Google OAuth provider for FastMCP. This module provides a complete Google OAuth integration that's ready to use with just a client ID and client secret. It handles all the complexity of Google's OAuth flow, token validation, and user management. Example: ```python from fastmcp import FastMCP from fastmcp.server.auth.providers.google import GoogleProvider # Simple Google OAuth protection auth = GoogleProvider( client_id="your-google-client-id.apps.googleusercontent.com", client_secret="your-google-client-secret" ) mcp = FastMCP("My Protected Server", auth=auth) ``` """ from __future__ import annotations import time import httpx from key_value.aio.protocols import AsyncKeyValue from pydantic import AnyHttpUrl, SecretStr, field_validator from pydantic_settings import BaseSettings, SettingsConfigDict from fastmcp.server.auth import TokenVerifier from fastmcp.server.auth.auth import AccessToken from fastmcp.server.auth.oauth_proxy import OAuthProxy from fastmcp.settings import ENV_FILE from fastmcp.utilities.auth import parse_scopes from fastmcp.utilities.logging import get_logger from fastmcp.utilities.types import NotSet, NotSetT logger = get_logger(__name__) class GoogleProviderSettings(BaseSettings): """Settings for Google OAuth provider.""" model_config = SettingsConfigDict( env_prefix="FASTMCP_SERVER_AUTH_GOOGLE_", env_file=ENV_FILE, extra="ignore", ) client_id: str | None = None client_secret: SecretStr | None = None base_url: AnyHttpUrl | str | None = None issuer_url: AnyHttpUrl | str | None = None redirect_path: str | None = None required_scopes: list[str] | None = None timeout_seconds: int | None = None allowed_client_redirect_uris: list[str] | None = None jwt_signing_key: str | None = None @field_validator("required_scopes", mode="before") @classmethod def _parse_scopes(cls, v): return parse_scopes(v) class GoogleTokenVerifier(TokenVerifier): """Token verifier for Google OAuth tokens. Google OAuth tokens are opaque (not JWTs), so we verify them by calling Google's tokeninfo API to check if they're valid and get user info. """ def __init__( self, *, required_scopes: list[str] | None = None, timeout_seconds: int = 10, ): """Initialize the Google token verifier. Args: required_scopes: Required OAuth scopes (e.g., ['openid', 'https://www.googleapis.com/auth/userinfo.email']) timeout_seconds: HTTP request timeout """ super().__init__(required_scopes=required_scopes) self.timeout_seconds = timeout_seconds async def verify_token(self, token: str) -> AccessToken | None: """Verify Google OAuth token by calling Google's tokeninfo API.""" try: async with httpx.AsyncClient(timeout=self.timeout_seconds) as client: # Use Google's tokeninfo endpoint to validate the token response = await client.get( "https://www.googleapis.com/oauth2/v1/tokeninfo", params={"access_token": token}, headers={"User-Agent": "FastMCP-Google-OAuth"}, ) if response.status_code != 200: logger.debug( "Google token verification failed: %d", response.status_code, ) return None token_info = response.json() # Check if token is expired expires_in = token_info.get("expires_in") if expires_in and int(expires_in) <= 0: logger.debug("Google token has expired") return None # Extract scopes from token info scope_string = token_info.get("scope", "") token_scopes = [ scope.strip() for scope in scope_string.split(" ") if scope.strip() ] # Check required scopes if self.required_scopes: token_scopes_set = set(token_scopes) required_scopes_set = set(self.required_scopes) if not required_scopes_set.issubset(token_scopes_set): logger.debug( "Google token missing required scopes. Has %d, needs %d", len(token_scopes_set), len(required_scopes_set), ) return None # Get additional user info if we have the right scopes user_data = {} if "openid" in token_scopes or "profile" in token_scopes: try: userinfo_response = await client.get( "https://www.googleapis.com/oauth2/v2/userinfo", headers={ "Authorization": f"Bearer {token}", "User-Agent": "FastMCP-Google-OAuth", }, ) if userinfo_response.status_code == 200: user_data = userinfo_response.json() except Exception as e: logger.debug("Failed to fetch Google user info: %s", e) # Calculate expiration time expires_at = None if expires_in: expires_at = int(time.time() + int(expires_in)) # Create AccessToken with Google user info access_token = AccessToken( token=token, client_id=token_info.get( "audience", "unknown" ), # Use audience as client_id scopes=token_scopes, expires_at=expires_at, claims={ "sub": user_data.get("id") or token_info.get("user_id", "unknown"), "email": user_data.get("email"), "name": user_data.get("name"), "picture": user_data.get("picture"), "given_name": user_data.get("given_name"), "family_name": user_data.get("family_name"), "locale": user_data.get("locale"), "google_user_data": user_data, "google_token_info": token_info, }, ) logger.debug("Google token verified successfully") return access_token except httpx.RequestError as e: logger.debug("Failed to verify Google token: %s", e) return None except Exception as e: logger.debug("Google token verification error: %s", e) return None class GoogleProvider(OAuthProxy): """Complete Google OAuth provider for FastMCP. This provider makes it trivial to add Google OAuth protection to any FastMCP server. Just provide your Google OAuth app credentials and a base URL, and you're ready to go. Features: - Transparent OAuth proxy to Google - Automatic token validation via Google's tokeninfo API - User information extraction from Google APIs - Minimal configuration required Example: ```python from fastmcp import FastMCP from fastmcp.server.auth.providers.google import GoogleProvider auth = GoogleProvider( client_id="123456789.apps.googleusercontent.com", client_secret="GOCSPX-abc123...", base_url="https://my-server.com" ) mcp = FastMCP("My App", auth=auth) ``` """ def __init__( self, *, client_id: str | NotSetT = NotSet, client_secret: str | NotSetT = NotSet, base_url: AnyHttpUrl | str | NotSetT = NotSet, issuer_url: AnyHttpUrl | str | NotSetT = NotSet, redirect_path: str | NotSetT = NotSet, required_scopes: list[str] | NotSetT = NotSet, timeout_seconds: int | NotSetT = NotSet, allowed_client_redirect_uris: list[str] | NotSetT = NotSet, client_storage: AsyncKeyValue | None = None, jwt_signing_key: str | bytes | NotSetT = NotSet, require_authorization_consent: bool = True, ): """Initialize Google OAuth provider. Args: client_id: Google OAuth client ID (e.g., "123456789.apps.googleusercontent.com") client_secret: Google OAuth client secret (e.g., "GOCSPX-abc123...") base_url: Public URL where OAuth endpoints will be accessible (includes any mount path) issuer_url: Issuer URL for OAuth metadata (defaults to base_url). Use root-level URL to avoid 404s during discovery when mounting under a path. redirect_path: Redirect path configured in Google OAuth app (defaults to "/auth/callback") required_scopes: Required Google scopes (defaults to ["openid"]). Common scopes include: - "openid" for OpenID Connect (default) - "https://www.googleapis.com/auth/userinfo.email" for email access - "https://www.googleapis.com/auth/userinfo.profile" for profile info timeout_seconds: HTTP request timeout for Google API calls allowed_client_redirect_uris: List of allowed redirect URI patterns for MCP clients. If None (default), all URIs are allowed. If empty list, no URIs are allowed. client_storage: Storage backend for OAuth state (client registrations, encrypted tokens). If None, a DiskStore will be created in the data directory (derived from `platformdirs`). The disk store will be encrypted using a key derived from the JWT Signing Key. jwt_signing_key: Secret for signing FastMCP JWT tokens (any string or bytes). If bytes are provided, they will be used as is. If a string is provided, it will be derived into a 32-byte key. If not provided, the upstream client secret will be used to derive a 32-byte key using PBKDF2. require_authorization_consent: Whether to require user consent before authorizing clients (default True). When True, users see a consent screen before being redirected to Google. When False, authorization proceeds directly without user confirmation. SECURITY WARNING: Only disable for local development or testing environments. """ settings = GoogleProviderSettings.model_validate( { k: v for k, v in { "client_id": client_id, "client_secret": client_secret, "base_url": base_url, "issuer_url": issuer_url, "redirect_path": redirect_path, "required_scopes": required_scopes, "timeout_seconds": timeout_seconds, "allowed_client_redirect_uris": allowed_client_redirect_uris, "jwt_signing_key": jwt_signing_key, }.items() if v is not NotSet } ) # Validate required settings if not settings.client_id: raise ValueError( "client_id is required - set via parameter or FASTMCP_SERVER_AUTH_GOOGLE_CLIENT_ID" ) if not settings.client_secret: raise ValueError( "client_secret is required - set via parameter or FASTMCP_SERVER_AUTH_GOOGLE_CLIENT_SECRET" ) # Apply defaults timeout_seconds_final = settings.timeout_seconds or 10 # Google requires at least one scope - openid is the minimal OIDC scope required_scopes_final = settings.required_scopes or ["openid"] allowed_client_redirect_uris_final = settings.allowed_client_redirect_uris # Create Google token verifier token_verifier = GoogleTokenVerifier( required_scopes=required_scopes_final, timeout_seconds=timeout_seconds_final, ) # Extract secret string from SecretStr client_secret_str = ( settings.client_secret.get_secret_value() if settings.client_secret else "" ) # Initialize OAuth proxy with Google endpoints super().__init__( upstream_authorization_endpoint="https://accounts.google.com/o/oauth2/v2/auth", upstream_token_endpoint="https://oauth2.googleapis.com/token", upstream_client_id=settings.client_id, upstream_client_secret=client_secret_str, token_verifier=token_verifier, base_url=settings.base_url, redirect_path=settings.redirect_path, issuer_url=settings.issuer_url or settings.base_url, # Default to base_url if not specified allowed_client_redirect_uris=allowed_client_redirect_uris_final, client_storage=client_storage, jwt_signing_key=settings.jwt_signing_key, require_authorization_consent=require_authorization_consent, ) logger.debug( "Initialized Google OAuth provider for client %s with scopes: %s", settings.client_id, required_scopes_final, )