Merge pull request #62 from nextcloud/feat/mcp-server

Feat: add mcp server

Author: lukasdotcom

appinfo/info.xml

@@ -46,5 +46,13 @@ Positive:
 			<image>nextcloud/context_agent</image>
 			<image-tag>1.2.2</image-tag>
 		</docker-install>
+        <routes>
+			<route>
+				<url>mcp</url>
+				<verb>POST,GET,DELETE</verb>
+				<access_level>USER</access_level>
+				<headers_to_exclude>[]</headers_to_exclude>
+			</route>
+		</routes>
 	</external-app>
 </info>

ex_app/lib/all_tools/audio2text.py

@@ -18,6 +18,7 @@ def transcribe_file(file_url: str) -> str:
 		:param file_url: The file URL to the media file in nextcloud (The user can input this using the smart picker for example)
 		:return: the transcription result
 		"""
+
 		task_input = {
 			'input': get_file_id_from_file_url(file_url),
 		}

ex_app/lib/all_tools/calendar.py

@@ -125,6 +125,7 @@ def find_free_time_slot_in_calendar(participants: list[str], slot_duration: Opti
 		:param end_time: the end time of the range within which to check for free slots (by default this will be 7 days after start_time; use the following format: 2025-01-31)
 		:return:
 		"""
+
 		me = nc.ocs('GET', '/ocs/v2.php/cloud/user')
 
 		attendees = 'ORGANIZER:mailto:'+me['email']+'\n'

ex_app/lib/all_tools/files.py

@@ -17,7 +17,7 @@ def get_file_content(file_path: str):
 		Get the content of a file
 		:param file_path: the path of the file
 		:return: 
-		""" 
+		"""
 
 		user_id = nc.ocs('GET', '/ocs/v2.php/cloud/user')["id"]
 
@@ -34,7 +34,7 @@ def get_folder_tree(depth: int):
 		Get the folder tree of the user
 		:param depth: the depth of the returned folder tree
 		:return: 
-		""" 
+		"""
 
 		return nc.ocs('GET', '/ocs/v2.php/apps/files/api/v1/folder-tree', json={'depth': depth}, response_type='json')
 
@@ -45,7 +45,7 @@ def create_public_sharing_link(path: str):
 		Creates a public sharing link for a file or folder
 		:param path: the path of the file or folder
 		:return: 
-		""" 
+		"""
 
 		response = nc.ocs('POST', '/ocs/v2.php/apps/files_sharing/api/v1/shares', json={
 					'path': path,

ex_app/lib/main.py

@@ -22,12 +22,21 @@
 
 from ex_app.lib.agent import react
 from ex_app.lib.logger import log
+from ex_app.lib.mcp_server import UserAuthMiddleware, ToolListMiddleware
 from ex_app.lib.provider import provider
 from ex_app.lib.tools import get_categories
 
 from contextvars import ContextVar
 from gettext import translation
+from fastmcp import FastMCP
 
+mcp = FastMCP(name="nextcloud")
+mcp.add_middleware(UserAuthMiddleware())
+mcp.add_middleware(ToolListMiddleware(mcp))
+mcp.stateless_http = True
+http_mcp_app = mcp.http_app("/", transport="http")
+
+fast_app = FastAPI(lifespan=http_mcp_app.lifespan)
 
 app_enabled = Event()
 
@@ -40,6 +49,11 @@ def _(text):
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
+    async with exapp_lifespan(app):
+        async with http_mcp_app.lifespan(app):
+            yield
+@asynccontextmanager
+async def exapp_lifespan(app: FastAPI):
     set_handlers(app, enabled_handler)
     start_bg_task()
     nc = NextcloudApp()
@@ -176,6 +190,8 @@ def start_bg_task():
     loop = asyncio.get_event_loop()
     loop.create_task(background_thread_task())
 
+APP.mount("/mcp", http_mcp_app)
+
 if __name__ == "__main__":
     # Wrapper around `uvicorn.run`.
     # You are free to call it directly, with just using the `APP_HOST` and `APP_PORT` variables from the environment.

ex_app/lib/mcp_server.py

@@ -0,0 +1,79 @@
+# SPDX-FileCopyrightText: 2024 LangChain, Inc.
+# SPDX-License-Identifier: MIT
+import time
+from functools import wraps
+
+from fastmcp.server.dependencies import get_context
+from nc_py_api import NextcloudApp
+from fastmcp.server.middleware import Middleware, MiddlewareContext, CallNext
+from fastmcp.tools import Tool
+from mcp import types as mt
+from ex_app.lib.tools import get_tools
+import requests
+
+def get_user(authorization_header: str, nc: NextcloudApp) -> str:
+	response = requests.get(
+		f"{nc.app_cfg.endpoint}/ocs/v2.php/cloud/user",
+		headers={
+			"Accept": "application/json",
+			"Ocs-Apirequest": "1",
+			"Authorization": authorization_header,
+		},
+	)
+	if response.status_code != 200:
+		raise Exception("Failed to get user info")
+	return response.json()["ocs"]["data"]["id"]
+
+
+class UserAuthMiddleware(Middleware):
+	async def on_message(self, context: MiddlewareContext, call_next):
+		# Middleware stores user info in context state
+		authorization_header = context.fastmcp_context.request_context.request.headers.get("Authorization")
+		if authorization_header is None:
+			raise Exception("Authorization header is missing/invalid")
+		nc = NextcloudApp()
+		user = get_user(authorization_header, nc)
+		nc.set_user(user)
+		context.fastmcp_context.set_state("nextcloud", nc)
+		return await call_next(context)
+
+
+LAST_MCP_TOOL_UPDATE = 0
+
+
+class ToolListMiddleware(Middleware):
+	def __init__(self, mcp):
+		self.mcp = mcp
+
+	async def on_message(
+			self,
+			context: MiddlewareContext[mt.ListToolsRequest],
+			call_next: CallNext[mt.ListToolsRequest, list[Tool]],
+	) -> list[Tool]:
+		global LAST_MCP_TOOL_UPDATE
+		if LAST_MCP_TOOL_UPDATE + 60 < time.time():
+			safe, dangerous = await get_tools(context.fastmcp_context.get_state("nextcloud"))
+			tools = await self.mcp.get_tools()
+			if LAST_MCP_TOOL_UPDATE + 60 < time.time():
+				for tool in tools.keys():
+					self.mcp.remove_tool(tool)
+				for tool in safe + dangerous:
+					if not hasattr(tool, "func") or tool.func is None:
+						continue
+					self.mcp.tool()(mcp_tool(tool.func))
+				LAST_MCP_TOOL_UPDATE = time.time()
+		return await call_next(context)
+
+# Regenerates the tools with the correct nc object
+def mcp_tool(tool):
+	@wraps(tool)
+	async def wrapper(*args, **kwargs):
+		ctx = get_context()
+		nc = ctx.get_state('nextcloud')
+		safe, dangerous = await get_tools(nc)
+		tools = safe + dangerous
+		for t in tools:
+			if hasattr(t, "func") and t.func and t.name == tool.__name__:
+				return t.func(*args, **kwargs)
+		raise RuntimeError("Tool not found")
+	return wrapper

ex_app/lib/tools.py

@@ -6,7 +6,6 @@
 import json
 from os.path import dirname
 
-from langchain_mcp_adapters.client import MultiServerMCPClient
 from nc_py_api import Nextcloud
 from ex_app.lib.all_tools.lib.decorator import timed_memoize