~launchpad-pqm/launchpad/devel

# Copyright 2009 Canonical Ltd.  This software is licensed under the

# GNU Affero General Public License version 3 (see the file LICENSE).

"""Helpers for examining the browser user_agent header."""

__metaclass__ = type

__all__ = [

    'get_user_agent_distroseries',

    'get_plural_text',

    ]

import re

def get_user_agent_distroseries(user_agent_string):

    """Return the `DistroSeries` version number from the user-agent."""

    if user_agent_string is None:

        return None

    # We're matching on the Ubuntu/10.09 section of the user-agent string.

    pattern = 'Ubuntu/(?P<version>\d*\.\d*)'

    match = re.search(pattern, user_agent_string)

    if match is not None:

        # Great, the browser is telling us the platform is Ubuntu.

        # Now grab the Ubuntu series/version number:

        return match.groupdict()['version']

    else:

        return None

def get_plural_text(count, singular, plural):

    """Return 'singular' if 'count' is 1, 'plural' otherwise."""

    if count == 1:

        return singular

    else:

        return plural