def get_resource(request, theme, file):
"""Returns a file from the theme."""
theme = get_theme(theme)
if theme is None:
raise NotFound()
f = theme.open_resource(file)
if f is None:
raise NotFound()
resp = Response(wrap_file(request.environ, f),
mimetype=mimetypes.guess_type(file)[0] or 'text/plain',
direct_passthrough=True)
resp.add_etag()
return resp.make_conditional(request)
