python-sdk/src/mcp/server/mcpserver/resources/resource_manager.py

113 lines
3.9 KiB
Python

"""Resource manager functionality."""
from __future__ import annotations
from collections.abc import Callable
from typing import TYPE_CHECKING, Any
from pydantic import AnyUrl
from mcp.server.mcpserver.resources.base import Resource
from mcp.server.mcpserver.resources.templates import ResourceTemplate
from mcp.server.mcpserver.utilities.logging import get_logger
from mcp.types import Annotations, Icon
if TYPE_CHECKING:
from mcp.server.mcpserver.server import Context
from mcp.server.session import ServerSessionT
from mcp.shared.context import LifespanContextT, RequestT
logger = get_logger(__name__)
class ResourceManager:
"""Manages MCPServer resources."""
def __init__(self, warn_on_duplicate_resources: bool = True):
self._resources: dict[str, Resource] = {}
self._templates: dict[str, ResourceTemplate] = {}
self.warn_on_duplicate_resources = warn_on_duplicate_resources
def add_resource(self, resource: Resource) -> Resource:
"""Add a resource to the manager.
Args:
resource: A Resource instance to add
Returns:
The added resource. If a resource with the same URI already exists,
returns the existing resource.
"""
logger.debug(
"Adding resource",
extra={
"uri": resource.uri,
"type": type(resource).__name__,
"resource_name": resource.name,
},
)
existing = self._resources.get(str(resource.uri))
if existing:
if self.warn_on_duplicate_resources:
logger.warning(f"Resource already exists: {resource.uri}")
return existing
self._resources[str(resource.uri)] = resource
return resource
def add_template(
self,
fn: Callable[..., Any],
uri_template: str,
name: str | None = None,
title: str | None = None,
description: str | None = None,
mime_type: str | None = None,
icons: list[Icon] | None = None,
annotations: Annotations | None = None,
meta: dict[str, Any] | None = None,
) -> ResourceTemplate:
"""Add a template from a function."""
template = ResourceTemplate.from_function(
fn,
uri_template=uri_template,
name=name,
title=title,
description=description,
mime_type=mime_type,
icons=icons,
annotations=annotations,
meta=meta,
)
self._templates[template.uri_template] = template
return template
async def get_resource(
self, uri: AnyUrl | str, context: Context[ServerSessionT, LifespanContextT, RequestT] | None = None
) -> Resource:
"""Get resource by URI, checking concrete resources first, then templates."""
uri_str = str(uri)
logger.debug("Getting resource", extra={"uri": uri_str})
# First check concrete resources
if resource := self._resources.get(uri_str):
return resource
# Then check templates
for template in self._templates.values():
if params := template.matches(uri_str):
try:
return await template.create_resource(uri_str, params, context=context)
except Exception as e: # pragma: no cover
raise ValueError(f"Error creating resource from template: {e}")
raise ValueError(f"Unknown resource: {uri}")
def list_resources(self) -> list[Resource]:
"""List all registered resources."""
logger.debug("Listing resources", extra={"count": len(self._resources)})
return list(self._resources.values())
def list_templates(self) -> list[ResourceTemplate]:
"""List all registered templates."""
logger.debug("Listing templates", extra={"count": len(self._templates)})
return list(self._templates.values())