propublica-mcp

from __future__ import annotations import asyncio import json import webbrowser from pathlib import Path from typing import Any, Literal from urllib.parse import urljoin, urlparse import anyio import httpx from mcp.client.auth import OAuthClientProvider, TokenStorage from mcp.shared.auth import ( OAuthClientInformationFull, OAuthClientMetadata, OAuthMetadata, ) from mcp.shared.auth import ( OAuthToken as OAuthToken, ) from pydantic import AnyHttpUrl, ValidationError from fastmcp import settings as fastmcp_global_settings from fastmcp.client.oauth_callback import ( create_oauth_callback_server, ) from fastmcp.utilities.http import find_available_port from fastmcp.utilities.logging import get_logger __all__ = ["OAuth"] logger = get_logger(__name__) def default_cache_dir() -> Path: return fastmcp_global_settings.home / "oauth-mcp-client-cache" class FileTokenStorage(TokenStorage): """ File-based token storage implementation for OAuth credentials and tokens. Implements the mcp.client.auth.TokenStorage protocol. Each instance is tied to a specific server URL for proper token isolation. """ def __init__(self, server_url: str, cache_dir: Path | None = None): """Initialize storage for a specific server URL.""" self.server_url = server_url self.cache_dir = cache_dir or default_cache_dir() self.cache_dir.mkdir(exist_ok=True, parents=True) @staticmethod def get_base_url(url: str) -> str: """Extract the base URL (scheme + host) from a URL.""" parsed = urlparse(url) return f"{parsed.scheme}://{parsed.netloc}" def get_cache_key(self) -> str: """Generate a safe filesystem key from the server's base URL.""" base_url = self.get_base_url(self.server_url) return ( base_url.replace("://", "_") .replace(".", "_") .replace("/", "_") .replace(":", "_") ) def _get_file_path(self, file_type: Literal["client_info", "tokens"]) -> Path: """Get the file path for the specified cache file type.""" key = self.get_cache_key() return self.cache_dir / f"{key}_{file_type}.json" async def get_tokens(self) -> OAuthToken | None: """Load tokens from file storage.""" path = self._get_file_path("tokens") try: tokens = OAuthToken.model_validate_json(path.read_text()) # now = datetime.datetime.now(datetime.timezone.utc) # if tokens.expires_at is not None and tokens.expires_at <= now: # logger.debug(f"Token expired for {self.get_base_url(self.server_url)}") # return None return tokens except (FileNotFoundError, json.JSONDecodeError, ValidationError) as e: logger.debug( f"Could not load tokens for {self.get_base_url(self.server_url)}: {e}" ) return None async def set_tokens(self, tokens: OAuthToken) -> None: """Save tokens to file storage.""" path = self._get_file_path("tokens") path.write_text(tokens.model_dump_json(indent=2)) logger.debug(f"Saved tokens for {self.get_base_url(self.server_url)}") async def get_client_info(self) -> OAuthClientInformationFull | None: """Load client information from file storage.""" path = self._get_file_path("client_info") try: client_info = OAuthClientInformationFull.model_validate_json( path.read_text() ) # Check if we have corresponding valid tokens # If no tokens exist, the OAuth flow was incomplete and we should # force a fresh client registration tokens = await self.get_tokens() if tokens is None: logger.debug( f"No tokens found for client info at {self.get_base_url(self.server_url)}. " "OAuth flow may have been incomplete. Clearing client info to force fresh registration." ) # Clear the incomplete client info client_info_path = self._get_file_path("client_info") client_info_path.unlink(missing_ok=True) return None return client_info except (FileNotFoundError, json.JSONDecodeError, ValidationError) as e: logger.debug( f"Could not load client info for {self.get_base_url(self.server_url)}: {e}" ) return None async def set_client_info(self, client_info: OAuthClientInformationFull) -> None: """Save client information to file storage.""" path = self._get_file_path("client_info") path.write_text(client_info.model_dump_json(indent=2)) logger.debug(f"Saved client info for {self.get_base_url(self.server_url)}") def clear(self) -> None: """Clear all cached data for this server.""" file_types: list[Literal["client_info", "tokens"]] = ["client_info", "tokens"] for file_type in file_types: path = self._get_file_path(file_type) path.unlink(missing_ok=True) logger.info(f"Cleared OAuth cache for {self.get_base_url(self.server_url)}") @classmethod def clear_all(cls, cache_dir: Path | None = None) -> None: """Clear all cached data for all servers.""" cache_dir = cache_dir or default_cache_dir() if not cache_dir.exists(): return file_types: list[Literal["client_info", "tokens"]] = ["client_info", "tokens"] for file_type in file_types: for file in cache_dir.glob(f"*_{file_type}.json"): file.unlink(missing_ok=True) logger.info("Cleared all OAuth client cache data.") async def discover_oauth_metadata( server_base_url: str, httpx_kwargs: dict[str, Any] | None = None ) -> OAuthMetadata | None: """ Discover OAuth metadata from the server using RFC 8414 well-known endpoint. Args: server_base_url: Base URL of the OAuth server (e.g., "https://example.com") httpx_kwargs: Additional kwargs for httpx client Returns: OAuth metadata if found, None otherwise """ well_known_url = urljoin(server_base_url, "/.well-known/oauth-authorization-server") logger.debug(f"Discovering OAuth metadata from: {well_known_url}") async with httpx.AsyncClient(**(httpx_kwargs or {})) as client: try: response = await client.get(well_known_url, timeout=10.0) if response.status_code == 200: logger.debug("Successfully discovered OAuth metadata") return OAuthMetadata.model_validate(response.json()) elif response.status_code == 404: logger.debug( "OAuth metadata not found (404) - server may not require auth" ) return None else: logger.warning(f"OAuth metadata request failed: {response.status_code}") return None except (httpx.RequestError, json.JSONDecodeError, ValidationError) as e: logger.debug(f"OAuth metadata discovery failed: {e}") return None async def check_if_auth_required( mcp_url: str, httpx_kwargs: dict[str, Any] | None = None ) -> bool: """ Check if the MCP endpoint requires authentication by making a test request. Returns: True if auth appears to be required, False otherwise """ async with httpx.AsyncClient(**(httpx_kwargs or {})) as client: try: # Try a simple request to the endpoint response = await client.get(mcp_url, timeout=5.0) # If we get 401/403, auth is likely required if response.status_code in (401, 403): return True # Check for WWW-Authenticate header if "WWW-Authenticate" in response.headers: return True # If we get a successful response, auth may not be required return False except httpx.RequestError: # If we can't connect, assume auth might be required return True def OAuth( mcp_url: str, scopes: str | list[str] | None = None, client_name: str = "FastMCP Client", token_storage_cache_dir: Path | None = None, additional_client_metadata: dict[str, Any] | None = None, ) -> OAuthClientProvider: """ Create an OAuthClientProvider for an MCP server. This is intended to be provided to the `auth` parameter of an httpx.AsyncClient (or appropriate FastMCP client/transport instance) Args: mcp_url: Full URL to the MCP endpoint (e.g. "http://host/mcp/sse/") scopes: OAuth scopes to request. Can be a space-separated string or a list of strings. client_name: Name for this client during registration token_storage_cache_dir: Directory for FileTokenStorage additional_client_metadata: Extra fields for OAuthClientMetadata Returns: OAuthClientProvider """ parsed_url = urlparse(mcp_url) server_base_url = f"{parsed_url.scheme}://{parsed_url.netloc}" # Setup OAuth client redirect_port = find_available_port() redirect_uri = f"http://127.0.0.1:{redirect_port}/callback" if isinstance(scopes, list): scopes = " ".join(scopes) client_metadata = OAuthClientMetadata( client_name=client_name, redirect_uris=[AnyHttpUrl(redirect_uri)], grant_types=["authorization_code", "refresh_token"], response_types=["code"], token_endpoint_auth_method="client_secret_post", scope=scopes, **(additional_client_metadata or {}), ) # Create server-specific token storage storage = FileTokenStorage( server_url=server_base_url, cache_dir=token_storage_cache_dir ) # Define OAuth handlers async def redirect_handler(authorization_url: str) -> None: """Open browser for authorization.""" logger.info(f"OAuth authorization URL: {authorization_url}") webbrowser.open(authorization_url) async def callback_handler() -> tuple[str, str | None]: """Handle OAuth callback and return (auth_code, state).""" # Create a future to capture the OAuth response response_future = asyncio.get_running_loop().create_future() # Create server with the future server = create_oauth_callback_server( port=redirect_port, server_url=server_base_url, response_future=response_future, ) # Run server until response is received with timeout logic async with anyio.create_task_group() as tg: tg.start_soon(server.serve) logger.info( f"🎧 OAuth callback server started on http://127.0.0.1:{redirect_port}" ) TIMEOUT = 300.0 # 5 minute timeout try: with anyio.fail_after(TIMEOUT): auth_code, state = await response_future return auth_code, state except TimeoutError: raise TimeoutError(f"OAuth callback timed out after {TIMEOUT} seconds") finally: server.should_exit = True await asyncio.sleep(0.1) # Allow server to shutdown gracefully tg.cancel_scope.cancel() # Create OAuth provider oauth_provider = OAuthClientProvider( server_url=server_base_url, client_metadata=client_metadata, storage=storage, redirect_handler=redirect_handler, callback_handler=callback_handler, ) return oauth_provider