by default it's r123:fffeeefffeee

    :param cs: changeset instance

    """

    from kallithea import CONFIG

    def_len = safe_int(CONFIG.get('show_sha_length', 12))

    show_rev = str2bool(CONFIG.get('show_revision_number', False))

    raw_id = cs.raw_id[:def_len]

    if show_rev:

        return 'r%s:%s' % (cs.revision, raw_id)

    else:

        return raw_id

def fmt_date(date):

    if date:

        return date.strftime("%Y-%m-%d %H:%M:%S").decode('utf8')

    return ""

def is_git(repository):

    if hasattr(repository, 'alias'):

        _type = repository.alias

    elif hasattr(repository, 'repo_type'):

        _type = repository.repo_type

    else:

        _type = repository

    return _type == 'git'

def is_hg(repository):

    if hasattr(repository, 'alias'):

        _type = repository.alias

    elif hasattr(repository, 'repo_type'):

        _type = repository.repo_type

    else:

        _type = repository

    return _type == 'hg'

def user_or_none(author):

    email = author_email(author)

    if email:

        user = User.get_by_email(email, case_insensitive=True, cache=True)

        if user is not None:

            return user

    return None

def email_or_none(author):

    if not author:

        return None

    user = user_or_none(author)

    if user is not None:

        return user.email # always use main email address - not necessarily the one used to find user

    # extract email from the commit string

    email = author_email(author)

    if email:

        return email

    # No valid email, not a valid user in the system, none!

    return None

def person(author, show_attr="username"):

    """Find the user identified by 'author', return one of the users attributes,

    default to the username attribute, None if there is no user"""

    # attr to return from fetched user

    person_getter = lambda usr: getattr(usr, show_attr)

    # if author is already an instance use it for extraction

    if isinstance(author, User):

        return person_getter(author)

    user = user_or_none(author)

    if user is not None:

        return person_getter(user)

    # Still nothing?  Just pass back the author name if any, else the email

    return author_name(author) or email(author)

def person_by_id(id_, show_attr="username"):

    # attr to return from fetched user

    person_getter = lambda usr: getattr(usr, show_attr)

    #maybe it's an ID ?

    if str(id_).isdigit() or isinstance(id_, int):

        id_ = int(id_)

        user = User.get(id_)

        if user is not None:

            return person_getter(user)

    return id_