static routes need their root directory on startup

[Pike]

Hi, I'm having a little pet project where I want to serve data from multiple discs, including USB drives.

aiohttp/aiohttp/web_urldispatcher.py

Lines 537 to 538 in 3edc43c

	if not directory.is_dir():
	raise ValueError("Not a directory")

errors when the drives aren't mounted. And does so in a way that's non-trivial to work around.

I've tried to track down if that's just convenience or for security-related functionality, but that code changed a number of times, and I've lost track.

I wonder if it'd be OK to just drop that check?

[Raphasha27]

Static routes in aiohttp serve files from a directory, and that directory must exist at the time the route is registered, not when a request comes in:

import os
from aiohttp import web

app = web.Application()

# This fails if /var/data/static doesn't exist at startup
app.router.add_static("/static", "/var/data/static")

Solutions:

1. Ensure the directory exists before starting the app:

os.makedirs("/var/data/static", exist_ok=True)
app.router.add_static("/static", "/var/data/static")

2. Serve files dynamically with a custom handler (if the directory is created later):

async def serve_static(request):
    path = os.path.join("/var/data/static", request.match_info["filename"])
    if not os.path.exists(path):
        raise web.HTTPNotFound()
    return web.FileResponse(path)

app.router.add_get("/static/{filename:.*}", serve_static)

3. Use aiohttp_static for deferred resolution:

# pip install aiohttp-static
from aiohttp_static import static_resource

app.router.register_resource(static_resource("/static", "/var/data/static"))

The create-server script you're using should ensure the directory exists before calling web.run_app(), or use solution #2 for directories that get created at runtime.