# __init__.py - general scheme interface
#
# Copyright (C) 2005 Arthur de Jong <arthur@tiefighter.et.tudelft.nl>
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

"""This package groups all the supported schemes.

A scheme module can be requested by the get_schememodule function.
Each module should export the following functions:

    get_info(link)
        Fetch the link and get some basic information from the
        document.

    get_document(link)
        Fetch the content of the referenced link."""

# Note: the difference between calling both methods is that the
#       content is only fetched if the link does not have a proble
#       and has a supported mimetype

# a map of schemes to modules
_schememodules={}

def get_schememodule(scheme):
    """Look up the correct module for the specified scheme."""
    if not _schememodules.has_key(scheme):
        try:
            _schememodules[scheme]=__import__('schemes.'+scheme,globals(),locals(),[scheme])
        except ImportError:
            _schememodules[scheme]=None
    return _schememodules[scheme]