refactor: replace lowlevel Server decorators with on_* constructor kwargs (#1985)
This commit is contained in:
Max Isbey
GitHub
parent
d6d3ad9a7c
commit
0a22a9dc33
1 changed files with 3563 additions and 5481 deletions
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@ -2,82 +2,49 @@
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This module provides a framework for creating an MCP (Model Context Protocol) server.
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It allows you to easily define and handle various types of requests and notifications
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in an asynchronous manner.
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using constructor-based handler registration.
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Usage:
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1. Create a Server instance:
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server = Server("your_server_name")
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1. Define handler functions:
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async def my_list_tools(ctx, params):
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return types.ListToolsResult(tools=[...])
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2. Define request handlers using decorators:
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@server.list_prompts()
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async def handle_list_prompts(request: types.ListPromptsRequest) -> types.ListPromptsResult:
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# Implementation
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async def my_call_tool(ctx, params):
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return types.CallToolResult(content=[...])
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@server.get_prompt()
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async def handle_get_prompt(
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name: str, arguments: dict[str, str] | None
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) -> types.GetPromptResult:
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# Implementation
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2. Create a Server instance with on_* handlers:
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server = Server(
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"your_server_name",
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on_list_tools=my_list_tools,
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on_call_tool=my_call_tool,
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)
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@server.list_tools()
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async def handle_list_tools(request: types.ListToolsRequest) -> types.ListToolsResult:
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# Implementation
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@server.call_tool()
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async def handle_call_tool(
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name: str, arguments: dict | None
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) -> list[types.TextContent | types.ImageContent | types.EmbeddedResource]:
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# Implementation
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@server.list_resource_templates()
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async def handle_list_resource_templates() -> list[types.ResourceTemplate]:
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# Implementation
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3. Define notification handlers if needed:
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@server.progress_notification()
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async def handle_progress(
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progress_token: str | int, progress: float, total: float | None,
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message: str | None
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) -> None:
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# Implementation
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4. Run the server:
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3. Run the server:
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async def main():
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async with mcp.server.stdio.stdio_server() as (read_stream, write_stream):
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await server.run(
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read_stream,
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write_stream,
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InitializationOptions(
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server_name="your_server_name",
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server_version="your_version",
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capabilities=server.get_capabilities(
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notification_options=NotificationOptions(),
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experimental_capabilities={},
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),
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),
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server.create_initialization_options(),
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)
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asyncio.run(main())
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The Server class provides methods to register handlers for various MCP requests and
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notifications. It automatically manages the request context and handles incoming
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messages from the client.
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The Server class dispatches incoming requests and notifications to registered
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handler callables by method string.
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"""
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from __future__ import annotations
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import base64
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import contextvars
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import json
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import logging
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import warnings
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from collections.abc import AsyncIterator, Awaitable, Callable, Iterable
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from collections.abc import AsyncIterator, Awaitable, Callable
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from contextlib import AbstractAsyncContextManager, AsyncExitStack, asynccontextmanager
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from importlib.metadata import version as importlib_version
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from typing import Any, Generic, TypeAlias, cast
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from typing import Any, Generic
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import anyio
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import jsonschema
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from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
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from starlette.applications import Starlette
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from starlette.middleware import Middleware
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@ -94,30 +61,20 @@ from mcp.server.auth.settings import AuthSettings
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from mcp.server.context import ServerRequestContext
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from mcp.server.experimental.request_context import Experimental
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from mcp.server.lowlevel.experimental import ExperimentalHandlers
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from mcp.server.lowlevel.func_inspection import create_call_wrapper
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from mcp.server.lowlevel.helper_types import ReadResourceContents
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from mcp.server.models import InitializationOptions
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from mcp.server.session import ServerSession
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from mcp.server.streamable_http import EventStore
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from mcp.server.streamable_http_manager import StreamableHTTPASGIApp, StreamableHTTPSessionManager
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from mcp.server.transport_security import TransportSecuritySettings
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from mcp.shared.exceptions import MCPError, UrlElicitationRequiredError
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from mcp.shared.exceptions import MCPError
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from mcp.shared.message import ServerMessageMetadata, SessionMessage
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from mcp.shared.session import RequestResponder
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from mcp.shared.tool_name_validation import validate_and_warn_tool_name
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logger = logging.getLogger(__name__)
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LifespanResultT = TypeVar("LifespanResultT", default=Any)
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RequestT = TypeVar("RequestT", default=Any)
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# type aliases for tool call results
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StructuredContent: TypeAlias = dict[str, Any]
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UnstructuredContent: TypeAlias = Iterable[types.ContentBlock]
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CombinationContent: TypeAlias = tuple[UnstructuredContent, StructuredContent]
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# This will be properly typed in each Server instance's context
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request_ctx: contextvars.ContextVar[ServerRequestContext[Any, Any]] = contextvars.ContextVar("request_ctx")
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request_ctx: contextvars.ContextVar[ServerRequestContext[Any]] = contextvars.ContextVar("request_ctx")
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class NotificationOptions:
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@ -128,7 +85,7 @@ class NotificationOptions:
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@asynccontextmanager
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async def lifespan(_: Server[LifespanResultT, RequestT]) -> AsyncIterator[dict[str, Any]]:
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async def lifespan(_: Server[LifespanResultT]) -> AsyncIterator[dict[str, Any]]:
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"""Default lifespan context manager that does nothing.
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Args:
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@ -140,10 +97,15 @@ async def lifespan(_: Server[LifespanResultT, RequestT]) -> AsyncIterator[dict[s
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yield {}
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class Server(Generic[LifespanResultT, RequestT]):
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async def _ping_handler(ctx: ServerRequestContext[Any], params: types.RequestParams | None) -> types.EmptyResult:
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return types.EmptyResult()
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class Server(Generic[LifespanResultT]):
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def __init__(
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self,
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name: str,
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*,
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version: str | None = None,
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title: str | None = None,
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description: str | None = None,
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@ -151,9 +113,80 @@ class Server(Generic[LifespanResultT, RequestT]):
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website_url: str | None = None,
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icons: list[types.Icon] | None = None,
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lifespan: Callable[
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[Server[LifespanResultT, RequestT]],
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[Server[LifespanResultT]],
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AbstractAsyncContextManager[LifespanResultT],
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] = lifespan,
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# Request handlers
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on_list_tools: Callable[
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[ServerRequestContext[LifespanResultT], types.PaginatedRequestParams | None],
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Awaitable[types.ListToolsResult],
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]
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| None = None,
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on_call_tool: Callable[
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[ServerRequestContext[LifespanResultT], types.CallToolRequestParams],
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Awaitable[types.CallToolResult | types.CreateTaskResult],
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]
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| None = None,
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on_list_resources: Callable[
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[ServerRequestContext[LifespanResultT], types.PaginatedRequestParams | None],
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Awaitable[types.ListResourcesResult],
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]
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| None = None,
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on_list_resource_templates: Callable[
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[ServerRequestContext[LifespanResultT], types.PaginatedRequestParams | None],
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Awaitable[types.ListResourceTemplatesResult],
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]
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| None = None,
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on_read_resource: Callable[
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[ServerRequestContext[LifespanResultT], types.ReadResourceRequestParams],
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Awaitable[types.ReadResourceResult],
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]
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| None = None,
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on_subscribe_resource: Callable[
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[ServerRequestContext[LifespanResultT], types.SubscribeRequestParams],
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Awaitable[types.EmptyResult],
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]
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| None = None,
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on_unsubscribe_resource: Callable[
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[ServerRequestContext[LifespanResultT], types.UnsubscribeRequestParams],
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Awaitable[types.EmptyResult],
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]
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| None = None,
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on_list_prompts: Callable[
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[ServerRequestContext[LifespanResultT], types.PaginatedRequestParams | None],
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Awaitable[types.ListPromptsResult],
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]
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| None = None,
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on_get_prompt: Callable[
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[ServerRequestContext[LifespanResultT], types.GetPromptRequestParams],
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Awaitable[types.GetPromptResult],
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]
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| None = None,
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on_completion: Callable[
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[ServerRequestContext[LifespanResultT], types.CompleteRequestParams],
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Awaitable[types.CompleteResult],
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]
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| None = None,
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on_set_logging_level: Callable[
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[ServerRequestContext[LifespanResultT], types.SetLevelRequestParams],
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Awaitable[types.EmptyResult],
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]
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| None = None,
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on_ping: Callable[
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[ServerRequestContext[LifespanResultT], types.RequestParams | None],
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Awaitable[types.EmptyResult],
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] = _ping_handler,
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# Notification handlers
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on_roots_list_changed: Callable[
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[ServerRequestContext[LifespanResultT], types.NotificationParams | None],
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Awaitable[None],
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]
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| None = None,
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on_progress: Callable[
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[ServerRequestContext[LifespanResultT], types.ProgressNotificationParams],
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Awaitable[None],
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]
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| None = None,
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):
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self.name = name
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self.version = version
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@ -163,15 +196,64 @@ class Server(Generic[LifespanResultT, RequestT]):
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self.website_url = website_url
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self.icons = icons
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self.lifespan = lifespan
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self.request_handlers: dict[type, Callable[..., Awaitable[types.ServerResult]]] = {
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types.PingRequest: _ping_handler,
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}
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self.notification_handlers: dict[type, Callable[..., Awaitable[None]]] = {}
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self._tool_cache: dict[str, types.Tool] = {}
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self._experimental_handlers: ExperimentalHandlers | None = None
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self._request_handlers: dict[str, Callable[[ServerRequestContext[LifespanResultT], Any], Awaitable[Any]]] = {}
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self._notification_handlers: dict[
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str, Callable[[ServerRequestContext[LifespanResultT], Any], Awaitable[None]]
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] = {}
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self._experimental_handlers: ExperimentalHandlers[LifespanResultT] | None = None
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self._session_manager: StreamableHTTPSessionManager | None = None
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logger.debug("Initializing server %r", name)
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# Populate internal handler dicts from on_* kwargs
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self._request_handlers.update(
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{
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method: handler
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for method, handler in {
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"ping": on_ping,
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"prompts/list": on_list_prompts,
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"prompts/get": on_get_prompt,
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"resources/list": on_list_resources,
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"resources/templates/list": on_list_resource_templates,
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"resources/read": on_read_resource,
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"resources/subscribe": on_subscribe_resource,
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"resources/unsubscribe": on_unsubscribe_resource,
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"tools/list": on_list_tools,
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"tools/call": on_call_tool,
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"logging/setLevel": on_set_logging_level,
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"completion/complete": on_completion,
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}.items()
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if handler is not None
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}
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)
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self._notification_handlers.update(
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{
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method: handler
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for method, handler in {
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"notifications/roots/list_changed": on_roots_list_changed,
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"notifications/progress": on_progress,
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}.items()
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if handler is not None
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}
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)
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def _add_request_handler(
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self,
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method: str,
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handler: Callable[[ServerRequestContext[LifespanResultT], Any], Awaitable[Any]],
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) -> None:
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"""Add a request handler, silently replacing any existing handler for the same method."""
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self._request_handlers[method] = handler
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def _has_handler(self, method: str) -> bool:
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"""Check if a handler is registered for the given method."""
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return method in self._request_handlers or method in self._notification_handlers
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# TODO: Rethink capabilities API. Currently capabilities are derived from registered
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# handlers but require NotificationOptions to be passed externally for list_changed
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# flags, and experimental_capabilities as a separate dict. Consider deriving capabilities
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# entirely from server state (e.g. constructor params for list_changed) instead of
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# requiring callers to assemble them at create_initialization_options() time.
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def create_initialization_options(
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self,
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notification_options: NotificationOptions | None = None,
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@ -214,25 +296,26 @@ class Server(Generic[LifespanResultT, RequestT]):
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completions_capability = None
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# Set prompt capabilities if handler exists
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if types.ListPromptsRequest in self.request_handlers:
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if "prompts/list" in self._request_handlers:
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prompts_capability = types.PromptsCapability(list_changed=notification_options.prompts_changed)
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# Set resource capabilities if handler exists
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if types.ListResourcesRequest in self.request_handlers:
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if "resources/list" in self._request_handlers:
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resources_capability = types.ResourcesCapability(
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subscribe=False, list_changed=notification_options.resources_changed
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subscribe="resources/subscribe" in self._request_handlers,
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list_changed=notification_options.resources_changed,
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)
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# Set tool capabilities if handler exists
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if types.ListToolsRequest in self.request_handlers:
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if "tools/list" in self._request_handlers:
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tools_capability = types.ToolsCapability(list_changed=notification_options.tools_changed)
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# Set logging capabilities if handler exists
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if types.SetLevelRequest in self.request_handlers:
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if "logging/setLevel" in self._request_handlers:
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logging_capability = types.LoggingCapability()
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# Set completions capabilities if handler exists
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if types.CompleteRequest in self.request_handlers:
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if "completion/complete" in self._request_handlers:
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completions_capability = types.CompletionsCapability()
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capabilities = types.ServerCapabilities(
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@ -248,12 +331,7 @@ class Server(Generic[LifespanResultT, RequestT]):
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return capabilities
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@property
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def request_context(self) -> ServerRequestContext[LifespanResultT, RequestT]:
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"""If called outside of a request context, this will raise a LookupError."""
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return request_ctx.get()
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@property
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def experimental(self) -> ExperimentalHandlers:
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def experimental(self) -> ExperimentalHandlers[LifespanResultT]:
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"""Experimental APIs for tasks and other features.
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WARNING: These APIs are experimental and may change without notice.
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@ -261,7 +339,10 @@ class Server(Generic[LifespanResultT, RequestT]):
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# We create this inline so we only add these capabilities _if_ they're actually used
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if self._experimental_handlers is None:
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self._experimental_handlers = ExperimentalHandlers(self, self.request_handlers, self.notification_handlers)
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self._experimental_handlers = ExperimentalHandlers(
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add_request_handler=self._add_request_handler,
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has_handler=self._has_handler,
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)
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return self._experimental_handlers
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@property
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@ -278,374 +359,6 @@ class Server(Generic[LifespanResultT, RequestT]):
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)
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return self._session_manager # pragma: no cover
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def list_prompts(self):
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def decorator(
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func: Callable[[], Awaitable[list[types.Prompt]]]
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| Callable[[types.ListPromptsRequest], Awaitable[types.ListPromptsResult]],
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):
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logger.debug("Registering handler for PromptListRequest")
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wrapper = create_call_wrapper(func, types.ListPromptsRequest)
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async def handler(req: types.ListPromptsRequest):
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result = await wrapper(req)
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# Handle both old style (list[Prompt]) and new style (ListPromptsResult)
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if isinstance(result, types.ListPromptsResult):
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return result
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else:
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# Old style returns list[Prompt]
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return types.ListPromptsResult(prompts=result)
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self.request_handlers[types.ListPromptsRequest] = handler
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return func
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return decorator
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def get_prompt(self):
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def decorator(
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func: Callable[[str, dict[str, str] | None], Awaitable[types.GetPromptResult]],
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):
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logger.debug("Registering handler for GetPromptRequest")
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async def handler(req: types.GetPromptRequest):
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prompt_get = await func(req.params.name, req.params.arguments)
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return prompt_get
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self.request_handlers[types.GetPromptRequest] = handler
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return func
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return decorator
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def list_resources(self):
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def decorator(
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func: Callable[[], Awaitable[list[types.Resource]]]
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| Callable[[types.ListResourcesRequest], Awaitable[types.ListResourcesResult]],
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):
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logger.debug("Registering handler for ListResourcesRequest")
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wrapper = create_call_wrapper(func, types.ListResourcesRequest)
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async def handler(req: types.ListResourcesRequest):
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result = await wrapper(req)
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# Handle both old style (list[Resource]) and new style (ListResourcesResult)
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if isinstance(result, types.ListResourcesResult):
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return result
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else:
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# Old style returns list[Resource]
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return types.ListResourcesResult(resources=result)
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self.request_handlers[types.ListResourcesRequest] = handler
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return func
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return decorator
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def list_resource_templates(self):
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def decorator(func: Callable[[], Awaitable[list[types.ResourceTemplate]]]):
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logger.debug("Registering handler for ListResourceTemplatesRequest")
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async def handler(_: Any):
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templates = await func()
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return types.ListResourceTemplatesResult(resource_templates=templates)
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self.request_handlers[types.ListResourceTemplatesRequest] = handler
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return func
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return decorator
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def read_resource(self):
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def decorator(
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func: Callable[[str], Awaitable[str | bytes | Iterable[ReadResourceContents]]],
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):
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logger.debug("Registering handler for ReadResourceRequest")
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async def handler(req: types.ReadResourceRequest):
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result = await func(req.params.uri)
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|
||||
def create_content(data: str | bytes, mime_type: str | None, meta: dict[str, Any] | None = None):
|
||||
# Note: ResourceContents uses Field(alias="_meta"), so we must use the alias key
|
||||
meta_kwargs: dict[str, Any] = {"_meta": meta} if meta is not None else {}
|
||||
match data:
|
||||
case str() as data:
|
||||
return types.TextResourceContents(
|
||||
uri=req.params.uri,
|
||||
text=data,
|
||||
mime_type=mime_type or "text/plain",
|
||||
**meta_kwargs,
|
||||
)
|
||||
case bytes() as data: # pragma: no branch
|
||||
return types.BlobResourceContents(
|
||||
uri=req.params.uri,
|
||||
blob=base64.b64encode(data).decode(),
|
||||
mime_type=mime_type or "application/octet-stream",
|
||||
**meta_kwargs,
|
||||
)
|
||||
|
||||
match result:
|
||||
case str() | bytes() as data: # pragma: lax no cover
|
||||
warnings.warn(
|
||||
"Returning str or bytes from read_resource is deprecated. "
|
||||
"Use Iterable[ReadResourceContents] instead.",
|
||||
DeprecationWarning,
|
||||
stacklevel=2,
|
||||
)
|
||||
content = create_content(data, None)
|
||||
case Iterable() as contents:
|
||||
contents_list = [
|
||||
create_content(
|
||||
content_item.content, content_item.mime_type, getattr(content_item, "meta", None)
|
||||
)
|
||||
for content_item in contents
|
||||
]
|
||||
return types.ReadResourceResult(contents=contents_list)
|
||||
case _: # pragma: no cover
|
||||
raise ValueError(f"Unexpected return type from read_resource: {type(result)}")
|
||||
|
||||
return types.ReadResourceResult(contents=[content]) # pragma: no cover
|
||||
|
||||
self.request_handlers[types.ReadResourceRequest] = handler
|
||||
return func
|
||||
|
||||
return decorator
|
||||
|
||||
def set_logging_level(self):
|
||||
def decorator(func: Callable[[types.LoggingLevel], Awaitable[None]]):
|
||||
logger.debug("Registering handler for SetLevelRequest")
|
||||
|
||||
async def handler(req: types.SetLevelRequest):
|
||||
await func(req.params.level)
|
||||
return types.EmptyResult()
|
||||
|
||||
self.request_handlers[types.SetLevelRequest] = handler
|
||||
return func
|
||||
|
||||
return decorator
|
||||
|
||||
def subscribe_resource(self):
|
||||
def decorator(func: Callable[[str], Awaitable[None]]):
|
||||
logger.debug("Registering handler for SubscribeRequest")
|
||||
|
||||
async def handler(req: types.SubscribeRequest):
|
||||
await func(req.params.uri)
|
||||
return types.EmptyResult()
|
||||
|
||||
self.request_handlers[types.SubscribeRequest] = handler
|
||||
return func
|
||||
|
||||
return decorator
|
||||
|
||||
def unsubscribe_resource(self):
|
||||
def decorator(func: Callable[[str], Awaitable[None]]):
|
||||
logger.debug("Registering handler for UnsubscribeRequest")
|
||||
|
||||
async def handler(req: types.UnsubscribeRequest):
|
||||
await func(req.params.uri)
|
||||
return types.EmptyResult()
|
||||
|
||||
self.request_handlers[types.UnsubscribeRequest] = handler
|
||||
return func
|
||||
|
||||
return decorator
|
||||
|
||||
def list_tools(self):
|
||||
def decorator(
|
||||
func: Callable[[], Awaitable[list[types.Tool]]]
|
||||
| Callable[[types.ListToolsRequest], Awaitable[types.ListToolsResult]],
|
||||
):
|
||||
logger.debug("Registering handler for ListToolsRequest")
|
||||
|
||||
wrapper = create_call_wrapper(func, types.ListToolsRequest)
|
||||
|
||||
async def handler(req: types.ListToolsRequest):
|
||||
result = await wrapper(req)
|
||||
|
||||
# Handle both old style (list[Tool]) and new style (ListToolsResult)
|
||||
if isinstance(result, types.ListToolsResult):
|
||||
# Refresh the tool cache with returned tools
|
||||
for tool in result.tools:
|
||||
validate_and_warn_tool_name(tool.name)
|
||||
self._tool_cache[tool.name] = tool
|
||||
return result
|
||||
else:
|
||||
# Old style returns list[Tool]
|
||||
# Clear and refresh the entire tool cache
|
||||
self._tool_cache.clear()
|
||||
for tool in result:
|
||||
validate_and_warn_tool_name(tool.name)
|
||||
self._tool_cache[tool.name] = tool
|
||||
return types.ListToolsResult(tools=result)
|
||||
|
||||
self.request_handlers[types.ListToolsRequest] = handler
|
||||
return func
|
||||
|
||||
return decorator
|
||||
|
||||
def _make_error_result(self, error_message: str) -> types.CallToolResult:
|
||||
"""Create a CallToolResult with an error."""
|
||||
return types.CallToolResult(
|
||||
content=[types.TextContent(type="text", text=error_message)],
|
||||
is_error=True,
|
||||
)
|
||||
|
||||
async def _get_cached_tool_definition(self, tool_name: str) -> types.Tool | None:
|
||||
"""Get tool definition from cache, refreshing if necessary.
|
||||
|
||||
Returns the Tool object if found, None otherwise.
|
||||
"""
|
||||
if tool_name not in self._tool_cache:
|
||||
if types.ListToolsRequest in self.request_handlers:
|
||||
logger.debug("Tool cache miss for %s, refreshing cache", tool_name)
|
||||
await self.request_handlers[types.ListToolsRequest](None)
|
||||
|
||||
tool = self._tool_cache.get(tool_name)
|
||||
if tool is None:
|
||||
logger.warning("Tool '%s' not listed, no validation will be performed", tool_name)
|
||||
|
||||
return tool
|
||||
|
||||
def call_tool(self, *, validate_input: bool = True):
|
||||
"""Register a tool call handler.
|
||||
|
||||
Args:
|
||||
validate_input: If True, validates input against inputSchema. Default is True.
|
||||
|
||||
The handler validates input against inputSchema (if validate_input=True), calls the tool function,
|
||||
and builds a CallToolResult with the results:
|
||||
- Unstructured content (iterable of ContentBlock): returned in content
|
||||
- Structured content (dict): returned in structuredContent, serialized JSON text returned in content
|
||||
- Both: returned in content and structuredContent
|
||||
|
||||
If outputSchema is defined, validates structuredContent or errors if missing.
|
||||
"""
|
||||
|
||||
def decorator(
|
||||
func: Callable[
|
||||
[str, dict[str, Any]],
|
||||
Awaitable[
|
||||
UnstructuredContent
|
||||
| StructuredContent
|
||||
| CombinationContent
|
||||
| types.CallToolResult
|
||||
| types.CreateTaskResult
|
||||
],
|
||||
],
|
||||
):
|
||||
logger.debug("Registering handler for CallToolRequest")
|
||||
|
||||
async def handler(req: types.CallToolRequest):
|
||||
try:
|
||||
tool_name = req.params.name
|
||||
arguments = req.params.arguments or {}
|
||||
tool = await self._get_cached_tool_definition(tool_name)
|
||||
|
||||
# input validation
|
||||
if validate_input and tool:
|
||||
try:
|
||||
jsonschema.validate(instance=arguments, schema=tool.input_schema)
|
||||
except jsonschema.ValidationError as e:
|
||||
return self._make_error_result(f"Input validation error: {e.message}")
|
||||
|
||||
# tool call
|
||||
results = await func(tool_name, arguments)
|
||||
|
||||
# output normalization
|
||||
unstructured_content: UnstructuredContent
|
||||
maybe_structured_content: StructuredContent | None
|
||||
if isinstance(results, types.CallToolResult):
|
||||
return results
|
||||
elif isinstance(results, types.CreateTaskResult):
|
||||
# Task-augmented execution returns task info instead of result
|
||||
return results
|
||||
elif isinstance(results, tuple) and len(results) == 2:
|
||||
# tool returned both structured and unstructured content
|
||||
unstructured_content, maybe_structured_content = cast(CombinationContent, results)
|
||||
elif isinstance(results, dict):
|
||||
# tool returned structured content only
|
||||
maybe_structured_content = cast(StructuredContent, results)
|
||||
unstructured_content = [types.TextContent(type="text", text=json.dumps(results, indent=2))]
|
||||
elif hasattr(results, "__iter__"):
|
||||
# tool returned unstructured content only
|
||||
unstructured_content = cast(UnstructuredContent, results)
|
||||
maybe_structured_content = None
|
||||
else: # pragma: no cover
|
||||
return self._make_error_result(f"Unexpected return type from tool: {type(results).__name__}")
|
||||
|
||||
# output validation
|
||||
if tool and tool.output_schema is not None:
|
||||
if maybe_structured_content is None:
|
||||
return self._make_error_result(
|
||||
"Output validation error: outputSchema defined but no structured output returned"
|
||||
)
|
||||
else:
|
||||
try:
|
||||
jsonschema.validate(instance=maybe_structured_content, schema=tool.output_schema)
|
||||
except jsonschema.ValidationError as e:
|
||||
return self._make_error_result(f"Output validation error: {e.message}")
|
||||
|
||||
# result
|
||||
return types.CallToolResult(
|
||||
content=list(unstructured_content),
|
||||
structured_content=maybe_structured_content,
|
||||
is_error=False,
|
||||
)
|
||||
except UrlElicitationRequiredError:
|
||||
# Re-raise UrlElicitationRequiredError so it can be properly handled
|
||||
# by _handle_request, which converts it to an error response with code -32042
|
||||
raise
|
||||
except Exception as e:
|
||||
return self._make_error_result(str(e))
|
||||
|
||||
self.request_handlers[types.CallToolRequest] = handler
|
||||
return func
|
||||
|
||||
return decorator
|
||||
|
||||
def progress_notification(self):
|
||||
def decorator(
|
||||
func: Callable[[str | int, float, float | None, str | None], Awaitable[None]],
|
||||
):
|
||||
logger.debug("Registering handler for ProgressNotification")
|
||||
|
||||
async def handler(req: types.ProgressNotification):
|
||||
await func(
|
||||
req.params.progress_token,
|
||||
req.params.progress,
|
||||
req.params.total,
|
||||
req.params.message,
|
||||
)
|
||||
|
||||
self.notification_handlers[types.ProgressNotification] = handler
|
||||
return func
|
||||
|
||||
return decorator
|
||||
|
||||
def completion(self):
|
||||
"""Provides completions for prompts and resource templates"""
|
||||
|
||||
def decorator(
|
||||
func: Callable[
|
||||
[
|
||||
types.PromptReference | types.ResourceTemplateReference,
|
||||
types.CompletionArgument,
|
||||
types.CompletionContext | None,
|
||||
],
|
||||
Awaitable[types.Completion | None],
|
||||
],
|
||||
):
|
||||
logger.debug("Registering handler for CompleteRequest")
|
||||
|
||||
async def handler(req: types.CompleteRequest):
|
||||
completion = await func(req.params.ref, req.params.argument, req.params.context)
|
||||
return types.CompleteResult(
|
||||
completion=completion
|
||||
if completion is not None
|
||||
else types.Completion(values=[], total=None, has_more=None),
|
||||
)
|
||||
|
||||
self.request_handlers[types.CompleteRequest] = handler
|
||||
return func
|
||||
|
||||
return decorator
|
||||
|
||||
async def run(
|
||||
self,
|
||||
read_stream: MemoryObjectReceiveStream[SessionMessage | Exception],
|
||||
|
|
@ -715,7 +428,7 @@ class Server(Generic[LifespanResultT, RequestT]):
|
|||
if raise_exceptions:
|
||||
raise message
|
||||
case _:
|
||||
await self._handle_notification(message)
|
||||
await self._handle_notification(message, session, lifespan_context)
|
||||
|
||||
for warning in w: # pragma: lax no cover
|
||||
logger.info("Warning: %s: %s", warning.category.__name__, warning.message)
|
||||
|
|
@ -730,10 +443,9 @@ class Server(Generic[LifespanResultT, RequestT]):
|
|||
):
|
||||
logger.info("Processing request of type %s", type(req).__name__)
|
||||
|
||||
if handler := self.request_handlers.get(type(req)):
|
||||
if handler := self._request_handlers.get(req.method):
|
||||
logger.debug("Dispatching request of type %s", type(req).__name__)
|
||||
|
||||
token = None
|
||||
try:
|
||||
# Extract request context and close_sse_stream from message metadata
|
||||
request_data = None
|
||||
|
|
@ -744,32 +456,32 @@ class Server(Generic[LifespanResultT, RequestT]):
|
|||
close_sse_stream_cb = message.message_metadata.close_sse_stream
|
||||
close_standalone_sse_stream_cb = message.message_metadata.close_standalone_sse_stream
|
||||
|
||||
# Set our global state that can be retrieved via
|
||||
# app.get_request_context()
|
||||
client_capabilities = session.client_params.capabilities if session.client_params else None
|
||||
task_support = self._experimental_handlers.task_support if self._experimental_handlers else None
|
||||
# Get task metadata from request params if present
|
||||
task_metadata = None
|
||||
if hasattr(req, "params") and req.params is not None:
|
||||
task_metadata = getattr(req.params, "task", None)
|
||||
token = request_ctx.set(
|
||||
ServerRequestContext(
|
||||
request_id=message.request_id,
|
||||
meta=message.request_meta,
|
||||
session=session,
|
||||
lifespan_context=lifespan_context,
|
||||
experimental=Experimental(
|
||||
task_metadata=task_metadata,
|
||||
_client_capabilities=client_capabilities,
|
||||
_session=session,
|
||||
_task_support=task_support,
|
||||
),
|
||||
request=request_data,
|
||||
close_sse_stream=close_sse_stream_cb,
|
||||
close_standalone_sse_stream=close_standalone_sse_stream_cb,
|
||||
)
|
||||
ctx = ServerRequestContext(
|
||||
request_id=message.request_id,
|
||||
meta=message.request_meta,
|
||||
session=session,
|
||||
lifespan_context=lifespan_context,
|
||||
experimental=Experimental(
|
||||
task_metadata=task_metadata,
|
||||
_client_capabilities=client_capabilities,
|
||||
_session=session,
|
||||
_task_support=task_support,
|
||||
),
|
||||
request=request_data,
|
||||
close_sse_stream=close_sse_stream_cb,
|
||||
close_standalone_sse_stream=close_standalone_sse_stream_cb,
|
||||
)
|
||||
response = await handler(req)
|
||||
token = request_ctx.set(ctx)
|
||||
try:
|
||||
response = await handler(ctx, req.params)
|
||||
finally:
|
||||
request_ctx.reset(token)
|
||||
except MCPError as err:
|
||||
response = err.error
|
||||
except anyio.get_cancelled_exc_class():
|
||||
|
|
@ -779,10 +491,6 @@ class Server(Generic[LifespanResultT, RequestT]):
|
|||
if raise_exceptions: # pragma: no cover
|
||||
raise err
|
||||
response = types.ErrorData(code=0, message=str(err), data=None)
|
||||
finally:
|
||||
# Reset the global state after we are done
|
||||
if token is not None: # pragma: no branch
|
||||
request_ctx.reset(token)
|
||||
|
||||
await message.respond(response)
|
||||
else: # pragma: no cover
|
||||
|
|
@ -790,12 +498,29 @@ class Server(Generic[LifespanResultT, RequestT]):
|
|||
|
||||
logger.debug("Response sent")
|
||||
|
||||
async def _handle_notification(self, notify: Any):
|
||||
if handler := self.notification_handlers.get(type(notify)): # type: ignore
|
||||
async def _handle_notification(
|
||||
self,
|
||||
notify: types.ClientNotification,
|
||||
session: ServerSession,
|
||||
lifespan_context: LifespanResultT,
|
||||
) -> None:
|
||||
if handler := self._notification_handlers.get(notify.method):
|
||||
logger.debug("Dispatching notification of type %s", type(notify).__name__)
|
||||
|
||||
try:
|
||||
await handler(notify)
|
||||
client_capabilities = session.client_params.capabilities if session.client_params else None
|
||||
task_support = self._experimental_handlers.task_support if self._experimental_handlers else None
|
||||
ctx = ServerRequestContext(
|
||||
session=session,
|
||||
lifespan_context=lifespan_context,
|
||||
experimental=Experimental(
|
||||
task_metadata=None,
|
||||
_client_capabilities=client_capabilities,
|
||||
_session=session,
|
||||
_task_support=task_support,
|
||||
),
|
||||
)
|
||||
await handler(ctx, notify.params)
|
||||
except Exception: # pragma: no cover
|
||||
logger.exception("Uncaught exception in notification handler")
|
||||
|
||||
|
|
@ -910,7 +635,3 @@ class Server(Generic[LifespanResultT, RequestT]):
|
|||
middleware=middleware,
|
||||
lifespan=lambda app: session_manager.run(),
|
||||
)
|
||||
|
||||
|
||||
async def _ping_handler(request: types.PingRequest) -> types.ServerResult:
|
||||
return types.EmptyResult()
|
||||
|
|
|
|||
Loading…
Reference in a new issue