The API of http.server supports the directory optional parameter for CGIHTTPRequestHandler (which is inherited from SimpleHTTPRequestHandler). The CLI of http.server supports the corresponding -d/--directory option.

The -d/--directory option is passed to SimpleHTTPRequestHandler as the directory argument:

python -m http.server --directory /tmp/

But the -d/--directory option is not passed to CGIHTTPRequestHandler (which is enabled with the --cgi option):

python -m http.server --directory /tmp/ --cgi

So the option is ignored in that case.

The use of partial may cause bugs!

Here is reported that the protocol parameter (of the test function) is ignored because it’s set on the partial object instead of the handler class: https://bugs.python.org/issue46285

Thanks for mentioning this issue @merwok.

As you pointed out, function test in module http.server expects a real request handler class argument (SimpleHTTPRequestHandler or CGIHTTPRequestHandler), not a partial object partial(SimpleHTTPRequestHandler, directory=args.directory) or partial(CGIHTTPRequestHandler, directory=args.directory), so that the assignment of protocol_version class attribute in test is not ignored.

The partial object in the if __name__ == '__main__' branch of module http.server was introduced in the first place to pass the directory argument to the request handler class’s __init__ method called in method BaseServer.finish_request of module socketserver:

    def finish_request(self, request, client_address):
        """Finish one request by instantiating RequestHandlerClass."""
        self.RequestHandlerClass(request, client_address, self)

But BaseServer.finish_request is a factory method of BaseServer (the abstract creator) so it is designed to be overridden in subclasses to customize the instantiation of the request handler class BaseRequestHandler (the abstract product). So the proper way to instantiate SimpleHTTPRequestHandler and CGIHTTPRequestHandler with the directory argument is to override BaseServer.finish_request.

I have just updated my PR to implement this. It fixes both bpo-46285 and bpo-46436.

New changeset 2d08034 by Géry Ogam in branch 'main':
bpo-46436: Fix command-line option -d/--directory in module http.server (GH-30701)
2d08034

New changeset 502ad39 by Miss Islington (bot) in branch '3.9':
bpo-46436: Fix command-line option -d/--directory in module http.server (GH-30701)
502ad39

New changeset b271953 by Miss Islington (bot) in branch '3.10':
bpo-46436: Fix command-line option -d/--directory in module http.server (GH-30701)
b271953

Thanks again!