fastmcp/tests/auth/test_oauth_client.py
2025-06-20 13:06:48 -04:00

265 lines
9.7 KiB
Python

from collections.abc import Generator
from unittest.mock import patch
from urllib.parse import parse_qs, urlparse
import httpx
import pytest
import fastmcp.client.auth.oauth # Import module, not the function directly
from fastmcp.client import Client
from fastmcp.client.transports import StreamableHttpTransport
from fastmcp.server.auth.auth import ClientRegistrationOptions
from fastmcp.server.auth.providers.in_memory import InMemoryOAuthProvider
from fastmcp.server.server import FastMCP
from fastmcp.utilities.tests import run_server_in_process
def fastmcp_server(issuer_url: str):
"""Create a FastMCP server with OAuth authentication."""
server = FastMCP(
"TestServer",
auth=InMemoryOAuthProvider(
issuer_url=issuer_url,
client_registration_options=ClientRegistrationOptions(enabled=True),
),
)
@server.tool
def add(a: int, b: int) -> int:
"""Add two numbers together."""
return a + b
@server.resource("resource://test")
def get_test_resource() -> str:
"""Get a test resource."""
return "Hello from authenticated resource!"
return server
def run_server(host: str, port: int, **kwargs) -> None:
fastmcp_server(f"http://{host}:{port}").run(host=host, port=port, **kwargs)
@pytest.fixture(scope="module")
def streamable_http_server() -> Generator[str, None, None]:
with run_server_in_process(run_server, transport="streamable-http") as url:
yield f"{url}/mcp/"
@pytest.fixture()
def client_unauthorized(streamable_http_server: str) -> Client:
return Client(transport=StreamableHttpTransport(streamable_http_server))
class HeadlessOAuthProvider(httpx.Auth):
"""
OAuth provider that bypasses browser interaction for testing.
This simulates the complete OAuth flow programmatically by:
1. Discovering OAuth metadata from the server
2. Registering a client
3. Getting an authorization code (simulates user approval)
4. Exchanging it for an access token
5. Adding Bearer token to all requests
This enables testing OAuth-protected FastMCP servers without
requiring browser interaction or external OAuth providers.
"""
def __init__(self, mcp_url: str):
self.mcp_url = mcp_url
parsed_url = urlparse(mcp_url)
self.server_base_url = f"{parsed_url.scheme}://{parsed_url.netloc}"
self._access_token = None
async def async_auth_flow(self, request):
"""httpx.Auth interface - add Bearer token to requests."""
if not self._access_token:
await self._obtain_token()
if self._access_token:
request.headers["Authorization"] = f"Bearer {self._access_token}"
yield request
async def _obtain_token(self):
"""Get a valid access token by simulating the OAuth flow."""
import base64
import hashlib
import secrets
from mcp.shared.auth import OAuthClientInformationFull
from pydantic import AnyHttpUrl
# Generate PKCE challenge/verifier
code_verifier = (
base64.urlsafe_b64encode(secrets.token_bytes(32)).decode().rstrip("=")
)
code_challenge = (
base64.urlsafe_b64encode(hashlib.sha256(code_verifier.encode()).digest())
.decode()
.rstrip("=")
)
# Create HTTP client to talk to the server
async with httpx.AsyncClient() as http_client:
# 1. Discover OAuth metadata
metadata_url = (
f"{self.server_base_url}/.well-known/oauth-authorization-server"
)
response = await http_client.get(metadata_url)
response.raise_for_status()
metadata = response.json()
# 2. Register a client
client_info = OAuthClientInformationFull(
client_id="test_client_headless",
client_secret="test_secret_headless",
redirect_uris=[AnyHttpUrl("http://localhost:8080/callback")],
)
register_response = await http_client.post(
metadata["registration_endpoint"],
json=client_info.model_dump(mode="json"),
)
register_response.raise_for_status()
registered_client = register_response.json()
# 3. Get authorization code (simulate user approval)
auth_params = {
"response_type": "code",
"client_id": registered_client["client_id"],
"redirect_uri": "http://localhost:8080/callback",
"code_challenge": code_challenge,
"code_challenge_method": "S256",
"state": "test_state_headless",
}
auth_response = await http_client.get(
metadata["authorization_endpoint"],
params=auth_params,
follow_redirects=False,
)
# Extract auth code from redirect
if auth_response.status_code == 302:
redirect_url = auth_response.headers["location"]
parsed = urlparse(redirect_url)
query_params = parse_qs(parsed.query)
if "error" in query_params:
error = query_params["error"][0]
error_desc = query_params.get(
"error_description", ["Unknown error"]
)[0]
raise RuntimeError(
f"OAuth authorization failed: {error} - {error_desc}"
)
auth_code = query_params["code"][0]
# 4. Exchange auth code for access token
token_data = {
"grant_type": "authorization_code",
"client_id": registered_client["client_id"],
"client_secret": registered_client["client_secret"],
"code": auth_code,
"redirect_uri": "http://localhost:8080/callback",
"code_verifier": code_verifier,
}
token_response = await http_client.post(
metadata["token_endpoint"], data=token_data
)
token_response.raise_for_status()
token_info = token_response.json()
self._access_token = token_info["access_token"]
else:
raise RuntimeError(f"Authorization failed: {auth_response.status_code}")
@pytest.fixture()
def client_with_headless_oauth(
streamable_http_server: str,
) -> Generator[Client, None, None]:
"""Client with headless OAuth that bypasses browser interaction."""
# Patch the OAuth function to return our headless provider
def headless_oauth(*args, **kwargs):
mcp_url = args[0] if args else kwargs.get("mcp_url", "")
if not mcp_url:
raise ValueError("mcp_url is required")
return HeadlessOAuthProvider(mcp_url)
with patch("fastmcp.client.auth.oauth.OAuth", side_effect=headless_oauth):
client = Client(
transport=StreamableHttpTransport(streamable_http_server),
auth=fastmcp.client.auth.oauth.OAuth(mcp_url=streamable_http_server),
)
yield client
async def test_unauthorized(client_unauthorized: Client):
"""Test that unauthenticated requests are rejected."""
with pytest.raises(httpx.HTTPStatusError, match="401 Unauthorized"):
async with client_unauthorized:
pass
async def test_ping(client_with_headless_oauth: Client):
"""Test that we can ping the server."""
async with client_with_headless_oauth:
assert await client_with_headless_oauth.ping()
async def test_list_tools(client_with_headless_oauth: Client):
"""Test that we can list tools."""
async with client_with_headless_oauth:
tools = await client_with_headless_oauth.list_tools()
tool_names = [tool.name for tool in tools]
assert "add" in tool_names
async def test_call_tool(client_with_headless_oauth: Client):
"""Test that we can call a tool."""
async with client_with_headless_oauth:
result = await client_with_headless_oauth.call_tool("add", {"a": 5, "b": 3})
assert result[0].text == "8" # type: ignore[attr-defined]
async def test_list_resources(client_with_headless_oauth: Client):
"""Test that we can list resources."""
async with client_with_headless_oauth:
resources = await client_with_headless_oauth.list_resources()
resource_uris = [str(resource.uri) for resource in resources]
assert "resource://test" in resource_uris
async def test_read_resource(client_with_headless_oauth: Client):
"""Test that we can read a resource."""
async with client_with_headless_oauth:
resource = await client_with_headless_oauth.read_resource("resource://test")
assert resource[0].text == "Hello from authenticated resource!" # type: ignore[attr-defined]
async def test_oauth_server_metadata_discovery(streamable_http_server: str):
"""Test that we can discover OAuth metadata from the running server."""
parsed_url = urlparse(streamable_http_server)
server_base_url = f"{parsed_url.scheme}://{parsed_url.netloc}"
async with httpx.AsyncClient() as client:
# Test OAuth discovery endpoint
metadata_url = f"{server_base_url}/.well-known/oauth-authorization-server"
response = await client.get(metadata_url)
assert response.status_code == 200
metadata = response.json()
assert "authorization_endpoint" in metadata
assert "token_endpoint" in metadata
assert "registration_endpoint" in metadata
# The endpoints should be properly formed URLs
assert metadata["authorization_endpoint"].startswith(server_base_url)
assert metadata["token_endpoint"].startswith(server_base_url)