266 lines
9.5 KiB
Python
266 lines
9.5 KiB
Python
"""
|
|
Shared GitHub OAuth provider for MCP servers.
|
|
|
|
This module contains the common GitHub OAuth functionality used by both
|
|
the standalone authorization server and the legacy combined server.
|
|
|
|
NOTE: this is a simplified example for demonstration purposes.
|
|
This is not a production-ready implementation.
|
|
|
|
"""
|
|
|
|
import logging
|
|
import secrets
|
|
import time
|
|
from typing import Any
|
|
|
|
from pydantic import AnyHttpUrl
|
|
from pydantic_settings import BaseSettings, SettingsConfigDict
|
|
from starlette.exceptions import HTTPException
|
|
|
|
from mcp.server.auth.provider import (
|
|
AccessToken,
|
|
AuthorizationCode,
|
|
AuthorizationParams,
|
|
OAuthAuthorizationServerProvider,
|
|
RefreshToken,
|
|
construct_redirect_uri,
|
|
)
|
|
from mcp.shared._httpx_utils import create_mcp_http_client
|
|
from mcp.shared.auth import OAuthClientInformationFull, OAuthToken
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
class GitHubOAuthSettings(BaseSettings):
|
|
"""Common GitHub OAuth settings."""
|
|
|
|
model_config = SettingsConfigDict(env_prefix="MCP_")
|
|
|
|
# GitHub OAuth settings - MUST be provided via environment variables
|
|
github_client_id: str | None = None
|
|
github_client_secret: str | None = None
|
|
|
|
# GitHub OAuth URLs
|
|
github_auth_url: str = "https://github.com/login/oauth/authorize"
|
|
github_token_url: str = "https://github.com/login/oauth/access_token"
|
|
|
|
mcp_scope: str = "user"
|
|
github_scope: str = "read:user"
|
|
|
|
|
|
class GitHubOAuthProvider(OAuthAuthorizationServerProvider):
|
|
"""
|
|
OAuth provider that uses GitHub as the identity provider.
|
|
|
|
This provider handles the OAuth flow by:
|
|
1. Redirecting users to GitHub for authentication
|
|
2. Exchanging GitHub tokens for MCP tokens
|
|
3. Maintaining token mappings for API access
|
|
"""
|
|
|
|
def __init__(self, settings: GitHubOAuthSettings, github_callback_url: str):
|
|
self.settings = settings
|
|
self.github_callback_url = github_callback_url
|
|
self.clients: dict[str, OAuthClientInformationFull] = {}
|
|
self.auth_codes: dict[str, AuthorizationCode] = {}
|
|
self.tokens: dict[str, AccessToken] = {}
|
|
self.state_mapping: dict[str, dict[str, str | None]] = {}
|
|
# Maps MCP tokens to GitHub tokens
|
|
self.token_mapping: dict[str, str] = {}
|
|
|
|
async def get_client(self, client_id: str) -> OAuthClientInformationFull | None:
|
|
"""Get OAuth client information."""
|
|
return self.clients.get(client_id)
|
|
|
|
async def register_client(self, client_info: OAuthClientInformationFull):
|
|
"""Register a new OAuth client."""
|
|
self.clients[client_info.client_id] = client_info
|
|
|
|
async def authorize(self, client: OAuthClientInformationFull, params: AuthorizationParams) -> str:
|
|
"""Generate an authorization URL for GitHub OAuth flow."""
|
|
state = params.state or secrets.token_hex(16)
|
|
|
|
# Store state mapping for callback
|
|
self.state_mapping[state] = {
|
|
"redirect_uri": str(params.redirect_uri),
|
|
"code_challenge": params.code_challenge,
|
|
"redirect_uri_provided_explicitly": str(params.redirect_uri_provided_explicitly),
|
|
"client_id": client.client_id,
|
|
"resource": params.resource, # RFC 8707
|
|
}
|
|
|
|
# Build GitHub authorization URL
|
|
auth_url = (
|
|
f"{self.settings.github_auth_url}"
|
|
f"?client_id={self.settings.github_client_id}"
|
|
f"&redirect_uri={self.github_callback_url}"
|
|
f"&scope={self.settings.github_scope}"
|
|
f"&state={state}"
|
|
)
|
|
|
|
return auth_url
|
|
|
|
async def handle_github_callback(self, code: str, state: str) -> str:
|
|
"""Handle GitHub OAuth callback and return redirect URI."""
|
|
state_data = self.state_mapping.get(state)
|
|
if not state_data:
|
|
raise HTTPException(400, "Invalid state parameter")
|
|
|
|
redirect_uri = state_data["redirect_uri"]
|
|
code_challenge = state_data["code_challenge"]
|
|
redirect_uri_provided_explicitly = state_data["redirect_uri_provided_explicitly"] == "True"
|
|
client_id = state_data["client_id"]
|
|
resource = state_data.get("resource") # RFC 8707
|
|
|
|
# These are required values from our own state mapping
|
|
assert redirect_uri is not None
|
|
assert code_challenge is not None
|
|
assert client_id is not None
|
|
|
|
# Exchange code for token with GitHub
|
|
async with create_mcp_http_client() as client:
|
|
response = await client.post(
|
|
self.settings.github_token_url,
|
|
data={
|
|
"client_id": self.settings.github_client_id,
|
|
"client_secret": self.settings.github_client_secret,
|
|
"code": code,
|
|
"redirect_uri": self.github_callback_url,
|
|
},
|
|
headers={"Accept": "application/json"},
|
|
)
|
|
|
|
if response.status_code != 200:
|
|
raise HTTPException(400, "Failed to exchange code for token")
|
|
|
|
data = response.json()
|
|
|
|
if "error" in data:
|
|
raise HTTPException(400, data.get("error_description", data["error"]))
|
|
|
|
github_token = data["access_token"]
|
|
|
|
# Create MCP authorization code
|
|
new_code = f"mcp_{secrets.token_hex(16)}"
|
|
auth_code = AuthorizationCode(
|
|
code=new_code,
|
|
client_id=client_id,
|
|
redirect_uri=AnyHttpUrl(redirect_uri),
|
|
redirect_uri_provided_explicitly=redirect_uri_provided_explicitly,
|
|
expires_at=time.time() + 300,
|
|
scopes=[self.settings.mcp_scope],
|
|
code_challenge=code_challenge,
|
|
resource=resource, # RFC 8707
|
|
)
|
|
self.auth_codes[new_code] = auth_code
|
|
|
|
# Store GitHub token with MCP client_id
|
|
self.tokens[github_token] = AccessToken(
|
|
token=github_token,
|
|
client_id=client_id,
|
|
scopes=[self.settings.github_scope],
|
|
expires_at=None,
|
|
)
|
|
|
|
del self.state_mapping[state]
|
|
return construct_redirect_uri(redirect_uri, code=new_code, state=state)
|
|
|
|
async def load_authorization_code(
|
|
self, client: OAuthClientInformationFull, authorization_code: str
|
|
) -> AuthorizationCode | None:
|
|
"""Load an authorization code."""
|
|
return self.auth_codes.get(authorization_code)
|
|
|
|
async def exchange_authorization_code(
|
|
self, client: OAuthClientInformationFull, authorization_code: AuthorizationCode
|
|
) -> OAuthToken:
|
|
"""Exchange authorization code for tokens."""
|
|
if authorization_code.code not in self.auth_codes:
|
|
raise ValueError("Invalid authorization code")
|
|
|
|
# Generate MCP access token
|
|
mcp_token = f"mcp_{secrets.token_hex(32)}"
|
|
|
|
# Store MCP token
|
|
self.tokens[mcp_token] = AccessToken(
|
|
token=mcp_token,
|
|
client_id=client.client_id,
|
|
scopes=authorization_code.scopes,
|
|
expires_at=int(time.time()) + 3600,
|
|
resource=authorization_code.resource, # RFC 8707
|
|
)
|
|
|
|
# Find GitHub token for this client
|
|
github_token = next(
|
|
(
|
|
token
|
|
for token, data in self.tokens.items()
|
|
if (token.startswith("ghu_") or token.startswith("gho_")) and data.client_id == client.client_id
|
|
),
|
|
None,
|
|
)
|
|
|
|
# Store mapping between MCP token and GitHub token
|
|
if github_token:
|
|
self.token_mapping[mcp_token] = github_token
|
|
|
|
del self.auth_codes[authorization_code.code]
|
|
|
|
return OAuthToken(
|
|
access_token=mcp_token,
|
|
token_type="Bearer",
|
|
expires_in=3600,
|
|
scope=" ".join(authorization_code.scopes),
|
|
)
|
|
|
|
async def load_access_token(self, token: str) -> AccessToken | None:
|
|
"""Load and validate an access token."""
|
|
access_token = self.tokens.get(token)
|
|
if not access_token:
|
|
return None
|
|
|
|
# Check if expired
|
|
if access_token.expires_at and access_token.expires_at < time.time():
|
|
del self.tokens[token]
|
|
return None
|
|
|
|
return access_token
|
|
|
|
async def load_refresh_token(self, client: OAuthClientInformationFull, refresh_token: str) -> RefreshToken | None:
|
|
"""Load a refresh token - not supported in this example."""
|
|
return None
|
|
|
|
async def exchange_refresh_token(
|
|
self,
|
|
client: OAuthClientInformationFull,
|
|
refresh_token: RefreshToken,
|
|
scopes: list[str],
|
|
) -> OAuthToken:
|
|
"""Exchange refresh token - not supported in this example."""
|
|
raise NotImplementedError("Refresh tokens not supported")
|
|
|
|
async def revoke_token(self, token: str, token_type_hint: str | None = None) -> None:
|
|
"""Revoke a token."""
|
|
if token in self.tokens:
|
|
del self.tokens[token]
|
|
|
|
async def get_github_user_info(self, mcp_token: str) -> dict[str, Any]:
|
|
"""Get GitHub user info using MCP token."""
|
|
github_token = self.token_mapping.get(mcp_token)
|
|
if not github_token:
|
|
raise ValueError("No GitHub token found for MCP token")
|
|
|
|
async with create_mcp_http_client() as client:
|
|
response = await client.get(
|
|
"https://api.github.com/user",
|
|
headers={
|
|
"Authorization": f"Bearer {github_token}",
|
|
"Accept": "application/vnd.github.v3+json",
|
|
},
|
|
)
|
|
|
|
if response.status_code != 200:
|
|
raise ValueError(f"GitHub API error: {response.status_code}")
|
|
|
|
return response.json()
|