refactor oauth2.1 support to fastmcp native

auth/oauth_config.py

@@ -9,6 +9,7 @@ Supports both OAuth 2.0 and OAuth 2.1 with automatic client capability detection
 """
 
 import os
+from urllib.parse import urlparse
 from typing import List, Optional, Dict, Any
 
 
@@ -49,6 +50,10 @@ class OAuthConfig:
 
         # Redirect URI configuration
         self.redirect_uri = self._get_redirect_uri()
+        self.redirect_path = self._get_redirect_path(self.redirect_uri)
+
+        # Ensure FastMCP's Google provider picks up our existing configuration
+        self._apply_fastmcp_google_env()
 
     def _get_redirect_uri(self) -> str:
         """
@@ -62,6 +67,32 @@ class OAuthConfig:
             return explicit_uri
         return f"{self.base_url}/oauth2callback"
 
+    @staticmethod
+    def _get_redirect_path(uri: str) -> str:
+        """Extract the redirect path from a full redirect URI."""
+        parsed = urlparse(uri)
+        if parsed.scheme or parsed.netloc:
+            path = parsed.path or "/oauth2callback"
+        else:
+            # If the value was already a path, ensure it starts with '/'
+            path = uri if uri.startswith("/") else f"/{uri}"
+        return path or "/oauth2callback"
+
+    def _apply_fastmcp_google_env(self) -> None:
+        """Mirror legacy GOOGLE_* env vars into FastMCP Google provider settings."""
+        if not self.client_id:
+            return
+
+        def _set_if_absent(key: str, value: Optional[str]) -> None:
+            if value and key not in os.environ:
+                os.environ[key] = value
+
+        _set_if_absent("FASTMCP_SERVER_AUTH", "fastmcp.server.auth.providers.google.GoogleProvider" if self.oauth21_enabled else None)
+        _set_if_absent("FASTMCP_SERVER_AUTH_GOOGLE_CLIENT_ID", self.client_id)
+        _set_if_absent("FASTMCP_SERVER_AUTH_GOOGLE_CLIENT_SECRET", self.client_secret)
+        _set_if_absent("FASTMCP_SERVER_AUTH_GOOGLE_BASE_URL", self.get_oauth_base_url())
+        _set_if_absent("FASTMCP_SERVER_AUTH_GOOGLE_REDIRECT_PATH", self.redirect_path)
+
     def get_redirect_uris(self) -> List[str]:
         """
         Get all valid OAuth redirect URIs.
@@ -156,6 +187,7 @@ class OAuthConfig:
             "external_url": self.external_url,
             "effective_oauth_url": self.get_oauth_base_url(),
             "redirect_uri": self.redirect_uri,
+            "redirect_path": self.redirect_path,
             "client_configured": bool(self.client_id),
             "oauth21_enabled": self.oauth21_enabled,
             "pkce_required": self.pkce_required,
@@ -350,4 +382,4 @@ def get_oauth_redirect_uri() -> str:
 
 def is_stateless_mode() -> bool:
     """Check if stateless mode is enabled."""
-    return get_oauth_config().stateless_mode
+    return get_oauth_config().stateless_mode