Expose fastapi-mcp

Author: danlapid

README.md

@@ -1,6 +1,6 @@
-# Python Workers: FastMCP Example
+# Python Workers: FastAPI-MCP Example
 
-This is an example of a Python Worker that uses the FastMCP package.
+This is an example of a Python Worker that uses the FastAPI-MCP package.
 
 ## Adding Packages
 

src/httpx_patch.py

@@ -0,0 +1,11 @@
+from httpx._transports.jsfetch import AsyncJavascriptFetchTransport
+
+orig_handle_async_request = AsyncJavascriptFetchTransport.handle_async_request
+
+async def handle_async_request(self, request):
+    response = await orig_handle_async_request(self, request)
+    # fix content-encoding headers because the javascript fetch handles that
+    response.headers.update({"content-encoding": "identity"})
+    return response
+
+AsyncJavascriptFetchTransport.handle_async_request = handle_async_request

src/worker.py

@@ -2,45 +2,63 @@
 from workers import DurableObject
 from logger import logger
 import sys
+import httpx_patch  # noqa: F401
 sys.path.insert(0, "/session/metadata/vendor")
 sys.path.insert(0, "/session/metadata")
 
 
-def setup_server():
+def setup_server(env):
+    from fastapi import FastAPI, Request
+    from pydantic import BaseModel
+    from fastapi_mcp import FastApiMCP
     from exceptions import HTTPException, http_exception
-    from mcp.server.fastmcp import FastMCP
-    mcp = FastMCP("Demo")
-
-    @mcp.tool()
-    def add(a: int, b: int) -> int:
-        """Add two numbers"""
-        return a + b
-
-    @mcp.resource("greeting://{name}")
-    def get_greeting(name: str) -> str:
-        """Get a personalized greeting"""
-        return f"Hello, {name}!"
-
-    @mcp.tool()
-    def calculate_bmi(weight_kg: float, height_m: float) -> float:
-        """Calculate BMI given weight in kg and height in meters"""
-        return weight_kg / (height_m**2)
-
-    @mcp.prompt()
-    def echo_prompt(message: str) -> str:
-        """Create an echo prompt"""
-        return f"Please process this message: {message}"
-
-    app = mcp.sse_app()
+
+    app = FastAPI()
     app.add_exception_handler(HTTPException, http_exception)
+
+    mcp = FastApiMCP(app)
+
+    # Mount the MCP server directly to your FastAPI app
+    mcp.mount()
+    # Auto-generated operation_id (something like "read_user_users__user_id__get")
+    @app.get("/")
+    async def root():
+        return {"message": "Hello, World!"}
+
+    @app.get("/env")
+    async def root():
+        return {"message": "Here is an example of getting an environment variable: " + env.MESSAGE}
+
+    class Item(BaseModel):
+        name: str
+        description: str | None = None
+        price: float
+        tax: float | None = None
+
+    @app.post("/items/")
+    async def create_item(item: Item):
+        return item
+
+    @app.put("/items/{item_id}")
+    async def create_item(item_id: int, item: Item, q: str | None = None):
+        result = {"item_id": item_id, **item.dict()}
+        if q:
+            result.update({"q": q})
+        return result
+
+    @app.get("/items/{item_id}")
+    async def read_item(item_id: int):
+        return {"item_id": item_id}
+    
+    mcp.setup_server()
     return mcp, app
 
 
 class FastMCPServer(DurableObject):
     def __init__(self, ctx, env):
         self.ctx = ctx
         self.env = env
-        self.mcp, self.app = setup_server()
+        self.mcp, self.app = setup_server(self.env)
 
     async def call(self, request):
         import asgi

vendor.txt

@@ -1,2 +1,4 @@
-mcp
-structlog
+fastapi-mcp
+fastapi
+pydantic
+structlog

wrangler.jsonc

@@ -3,11 +3,10 @@
     "main": "src/worker.py",
     "compatibility_flags": [
         "python_workers",
-        "python_workers_durable_objects"
     ],
     "compatibility_date": "2025-04-10",
     "vars": {
-        "API_HOST": "example.com"
+        "MESSAGE": "hello world"
     },
     "rules": [
         {