#!/usr/bin/env python
"""Connector for mod_wsgi.
"""
import os
from os.path import isdir

from aspen import website_factory
from aspen._configuration import ConfigurationError

ROOT = None
_application = None

def application(environ, start_response):
    """Define a WSGI callable with the name mod_wsgi expects.

    mod_wsgi communicates to us in the WSGI environ, so we need this shim to
    get the website root we want to serve out of httpd.conf.

    """
    global ROOT, _application
    if _application is None:
        try:
            ROOT = environ['aspen.root']
        except KeyError:
            raise ConfigurationError("Please specify aspen.root using SetEnv.")
        if not isdir(ROOT):
            raise ConfigurationError("Path does not exist: " + ROOT)
        _application = website_factory(['--root', ROOT])
    return _application(environ, start_response)