FastAPI
The FastAPI package is supported in Python Workers.
FastAPI applications use a protocol called the Asynchronous Server Gateway Interface (ASGI). This means that FastAPI never reads from or writes to a socket itself. An ASGI application expects to be hooked up to an ASGI server, typically uvicorn. The ASGI server handles all of the raw sockets on the application’s behalf.
The Workers runtime provides an ASGI server directly to your Python Worker, which lets you use FastAPI in Python Workers.
Get Started
Clone the cloudflare/python-workers-examples repository and run the FastAPI example:
git clone https://github.com/cloudflare/python-workers-examplescd 03-fastapinpx wrangler@latest dev Example code
index.pyfrom fastapi import FastAPI, Requestfrom pydantic import BaseModel
async def on_fetch(request, env): import asgi
return await asgi.fetch(app, request, env)
app = FastAPI()
@app.get("/")
async def root(): return {"message": "Hello, World!"}
@app.get("/env")
async def root(req: Request): env = req.scope["env"] 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}