HTTP 500 when computing zim-file attribute

[benoit74]

1738458321524	ERROR: unsupported operand type(s) for +: 'NoneType' and 'str'
1738458321524	Traceback (most recent call last):
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/middleware/errors.py", line 165, in __call__
1738458321524	    await self.app(scope, receive, _send)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/middleware/cors.py", line 93, in __call__
1738458321524	    await self.simple_response(scope, receive, send, request_headers=headers)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/middleware/cors.py", line 144, in simple_response
1738458321524	    await self.app(scope, receive, send)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/middleware/exceptions.py", line 62, in __call__
1738458321524	    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/_exception_handler.py", line 62, in wrapped_app
1738458321524	    raise exc
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/_exception_handler.py", line 51, in wrapped_app
1738458321524	    await app(scope, receive, sender)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/routing.py", line 715, in __call__
1738458321524	    await self.middleware_stack(scope, receive, send)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/routing.py", line 735, in app
1738458321524	    await route.handle(scope, receive, send)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/routing.py", line 288, in handle
1738458321524	    await self.app(scope, receive, send)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/routing.py", line 76, in app
1738458321524	    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/_exception_handler.py", line 62, in wrapped_app
1738458321524	    raise exc
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/_exception_handler.py", line 51, in wrapped_app
1738458321524	    await app(scope, receive, sender)
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/routing.py", line 73, in app
1738458321524	    response = await f(request)
1738458321524	               ^^^^^^^^^^^^^^^^
1738458321524	  File "/usr/local/lib/python3.12/site-packages/fastapi/routing.py", line 301, in app
1738458321524	    raw_response = await run_endpoint_function(
1738458321524	                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1738458321524	  File "/usr/local/lib/python3.12/site-packages/fastapi/routing.py", line 214, in run_endpoint_function
1738458321524	    return await run_in_threadpool(dependant.call, **values)
1738458321524	           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1738458321524	  File "/usr/local/lib/python3.12/site-packages/starlette/concurrency.py", line 39, in run_in_threadpool
1738458321524	    return await anyio.to_thread.run_sync(func, *args)
1738458321524	           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1738458321524	  File "/usr/local/lib/python3.12/site-packages/anyio/to_thread.py", line 56, in run_sync
1738458321524	    return await get_async_backend().run_sync_in_worker_thread(
1738458321524	           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1738458321524	  File "/usr/local/lib/python3.12/site-packages/anyio/_backends/_asyncio.py", line 2461, in run_sync_in_worker_thread
1738458321524	    return await future
1738458321524	           ^^^^^^^^^^^^
1738458321524	  File "/usr/local/lib/python3.12/site-packages/anyio/_backends/_asyncio.py", line 962, in run
1738458321524	    result = context.run(func, *args)
1738458321524	             ^^^^^^^^^^^^^^^^^^^^^^^^
1738458321524	  File "/usr/local/lib/python3.12/site-packages/zimitfrontend/routes/requests.py", line 68, in create_task
1738458321524	    flags["zim-file"] = flags.get("zim-file", url.hostname) + f"_{ident}.zim"
1738458321524	                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
1738458321524	TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'
1738458321524	INFO:     100.64.6.209:58384 - "POST /api/v1/requests HTTP/1.1" 500 Internal