"""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 pydantic import AnyHttpUrl, SecretStr from pydantic_settings import BaseSettings, SettingsConfigDict from fastmcp.server.auth import TokenVerifier from fastmcp.server.auth.auth import AccessToken from fastmcp.server.auth.proxy import OAuthProxy from fastmcp.server.auth.registry import register_provider 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", extra="ignore", ) client_id: str | None = None client_secret: SecretStr | None = None base_url: AnyHttpUrl | str | None = None redirect_path: str | None = None required_scopes: list[str] | None = None timeout_seconds: int | None = None 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', '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 @register_provider("Google") 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" # Optional, defaults to http://localhost:8000 ) 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, redirect_path: str | NotSetT = NotSet, required_scopes: list[str] | None | NotSetT = NotSet, timeout_seconds: int | NotSetT = NotSet, ): """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 of your FastMCP server (for OAuth callbacks) redirect_path: Redirect path configured in Google OAuth app (defaults to "/oauth/callback") required_scopes: Required Google scopes (defaults to []). Common scopes include: - "openid" for OpenID Connect - "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 """ settings = GoogleProviderSettings.model_validate( { k: v for k, v in { "client_id": client_id, "client_secret": client_secret, "base_url": base_url, "redirect_path": redirect_path, "required_scopes": required_scopes, "timeout_seconds": timeout_seconds, }.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 base_url_final = settings.base_url or "http://localhost:8000" redirect_path_final = settings.redirect_path or "/oauth/callback" timeout_seconds_final = settings.timeout_seconds or 10 required_scopes_final = settings.required_scopes or [] # 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=base_url_final, redirect_path=redirect_path_final, issuer_url=base_url_final, # We act as the issuer for client registration ) logger.info( "Initialized Google OAuth provider for client %s with scopes: %s", settings.client_id, required_scopes_final, )