[cse491] HW8 Calling FileServer

C. Titus Brown ctb at msu.edu
Sun Nov 1 16:10:54 PST 2009

On Sun, Nov 01, 2009 at 06:36:41PM -0500, Andrew Kos wrote:
> Good Evening,
> In the homework guidelines, it says that we should be able to call
> FileServer as:
> import apps app = FileServer('/some/path')
> but with the process_form app we had to be able to pass a start_response and
> environ as arguments. Is there a different way that we're supposed to
> implement FileServer, or am I just missing something?

Hi Andrew,

first, the code example above is messed up -- a formatting error when
converting the .txt to .html... I've fixed


The real code must look something like this,

	from apps import FileServer
	app = FileServer('/some/path')

OK, so on to the actual question -- here, 'app' must be WSGI compliant,
which means that *when you call the object as if it were a function*,
it takes start_response and environ.  There are many ways to construct
such an object, and the above code is telling you that *this* object
must be constructed as

	app = FileServer('/some/path')

I think the most natural way to implement FileServer is as a class, 2nd
example under "Callables in WSGI", here:


although there are other ways to make it work.  The whole set of lab notes
through that section might be worth reading...

C. Titus Brown, ctb at msu.edu

More information about the cse491-fall-2009 mailing list