129 lines
7.2 KiB
Ruby
129 lines
7.2 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
module MCP
|
|
class Client
|
|
module OAuth
|
|
# Pluggable OAuth client configuration for the OAuth 2.1 Authorization Code + PKCE flow,
|
|
# handed to `MCP::Client::HTTP` via the `oauth:` keyword.
|
|
# Inspired by the OAuthClientProvider in the TypeScript SDK and the httpx.Auth-based provider
|
|
# in the Python SDK. For the non-interactive machine-to-machine `client_credentials` grant,
|
|
# use `ClientCredentialsProvider` instead.
|
|
#
|
|
# Required keyword arguments:
|
|
# - `client_metadata` - Hash sent to the authorization server's Dynamic Client
|
|
# Registration endpoint. Must include at minimum `redirect_uris`,
|
|
# `grant_types`, `response_types`, and `token_endpoint_auth_method`.
|
|
# When `application_type` is omitted, the SDK infers `"native"` or `"web"`
|
|
# from `redirect_uris` per SEP-837 before registering; an explicit value
|
|
# always wins.
|
|
# - `redirect_uri` - String: the redirect URI used for the authorization
|
|
# request. Must be one of `redirect_uris` in `client_metadata`.
|
|
# - `redirect_handler` - Callable invoked with the fully-built authorization
|
|
# URL (a `URI`). Implementations typically open the user's browser.
|
|
# - `callback_handler` - Callable invoked after `redirect_handler`. Returns
|
|
# `[code, state]` or `[code, state, iss]`, where `code` is the authorization code,
|
|
# `state` is the `state` parameter received on the redirect URI, and `iss` is
|
|
# the RFC 9207 `iss` parameter (or nil when the authorization response carried none).
|
|
# Returning the 3-element form opts into SEP-2468 issuer validation: a present `iss`
|
|
# must match the authorization server's issuer, and a nil `iss` is
|
|
# rejected when the AS advertises `authorization_response_iss_parameter_supported`.
|
|
# The 2-element form skips the check for backward compatibility.
|
|
#
|
|
# Optional keyword arguments:
|
|
# - `scope` - String of space-separated scopes to request when the server's
|
|
# `WWW-Authenticate` does not specify one.
|
|
# - `storage` - Object responding to `tokens`, `save_tokens(tokens)`,
|
|
# `client_information`, and `save_client_information(info)`. Defaults to
|
|
# an `InMemoryStorage`. Persisted `client_information` is stamped with
|
|
# an `"issuer"` member binding it to the authorization server that
|
|
# issued it (SEP-2352); when the authorization server changes, the SDK discards
|
|
# the stale registration and tokens and re-registers.
|
|
# - `client_id_metadata_document_url` - URL where the client publishes its Client ID Metadata Document
|
|
# (`draft-ietf-oauth-client-id-metadata-document-00` and the MCP authorization specification).
|
|
# When the authorization server advertises `client_id_metadata_document_supported: true`,
|
|
# the SDK uses this URL as the OAuth `client_id` and skips Dynamic Client Registration.
|
|
# Spec-required: `https://` scheme, a non-root path, and no fragment, userinfo, or `.`/`..` segments.
|
|
# The SDK additionally refuses to send query strings (the draft marks them only SHOULD NOT include,
|
|
# but different encodings of the same query would yield different `client_id` strings for the same document).
|
|
# The document served at the URL is a separate JSON artifact from the `client_metadata` keyword:
|
|
# DCR `client_metadata` MUST NOT include `client_id`, while the CIMD document MUST include `client_id` set
|
|
# to the URL, `client_name`, and `redirect_uris` covering `redirect_uri`.
|
|
class Provider
|
|
include StorageBackedProvider
|
|
|
|
# Raised when `Provider#initialize` is called with a `redirect_uri` that
|
|
# is neither HTTPS nor a loopback `http://` URL, per the MCP
|
|
# authorization spec's Communication Security requirement.
|
|
class InsecureRedirectURIError < ArgumentError; end
|
|
|
|
# Raised when the `redirect_uri` argument is not listed in
|
|
# `client_metadata[:redirect_uris]` / `["redirect_uris"]`. Registering
|
|
# the URI with the authorization server but then sending a different
|
|
# one with the authorization request would be rejected by the AS at
|
|
# runtime; failing at construction surfaces the bug earlier.
|
|
class UnregisteredRedirectURIError < ArgumentError; end
|
|
|
|
# Raised when `client_id_metadata_document_url` is provided but does not meet
|
|
# the structural requirements for a Client ID Metadata Document URL:
|
|
# HTTPS, non-root path, and no fragment, query, userinfo, or `.`/`..` segments.
|
|
# The CIMD URL is sent to the authorization server as the OAuth `client_id`,
|
|
# so the same Communication Security guarantee that protects the redirect URI
|
|
# applies and the value must unambiguously identify the document.
|
|
class InvalidClientIDMetadataDocumentURLError < ArgumentError; end
|
|
|
|
attr_reader :client_metadata,
|
|
:redirect_uri,
|
|
:scope,
|
|
:storage,
|
|
:redirect_handler,
|
|
:callback_handler,
|
|
:client_id_metadata_document_url
|
|
|
|
def initialize(
|
|
client_metadata:,
|
|
redirect_uri:,
|
|
redirect_handler:,
|
|
callback_handler:,
|
|
scope: nil,
|
|
storage: nil,
|
|
client_id_metadata_document_url: nil
|
|
)
|
|
unless Discovery.secure_url?(redirect_uri)
|
|
raise InsecureRedirectURIError,
|
|
"redirect_uri #{redirect_uri.inspect} must use https or be a loopback http URL " \
|
|
"(localhost, 127.0.0.0/8, or ::1) per the MCP authorization Communication Security requirement."
|
|
end
|
|
|
|
registered = Array(client_metadata[:redirect_uris] || client_metadata["redirect_uris"])
|
|
unless registered.include?(redirect_uri)
|
|
raise UnregisteredRedirectURIError,
|
|
"redirect_uri #{redirect_uri.inspect} must be listed in client_metadata[:redirect_uris] " \
|
|
"(got #{registered.inspect}); otherwise the authorization server will reject the authorization request."
|
|
end
|
|
|
|
if client_id_metadata_document_url && !Discovery.client_id_metadata_document_url?(client_id_metadata_document_url)
|
|
raise InvalidClientIDMetadataDocumentURLError,
|
|
"client_id_metadata_document_url #{client_id_metadata_document_url.inspect} must be an https URL " \
|
|
"with a non-root path and no fragment, query, userinfo, or `.`/`..` segments, " \
|
|
"per the MCP authorization specification and `draft-ietf-oauth-client-id-metadata-document`."
|
|
end
|
|
|
|
@client_metadata = client_metadata
|
|
@redirect_uri = redirect_uri
|
|
@redirect_handler = redirect_handler
|
|
@callback_handler = callback_handler
|
|
@scope = scope
|
|
@storage = storage || InMemoryStorage.new
|
|
@client_id_metadata_document_url = client_id_metadata_document_url
|
|
end
|
|
|
|
# Identifies the OAuth flow this provider drives.
|
|
# `Flow` dispatches on this rather than inspecting `client_metadata[:grant_types]`,
|
|
# which is protocol metadata for the authorization server, not an SDK control signal.
|
|
def authorization_flow
|
|
:authorization_code
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end
|