def truncate_string(text, strip_html=True, chars=255, truncate='…', at_word_boundary=False):
    """Truncate a string to a certain length, removing line breaks and mutliple
    spaces, optionally removing HTML, and appending a 'truncate' string.

    Keyword arguments:
    strip_html -- boolean.
    chars -- Number of characters to return.
    at_word_boundary -- Only truncate at a word boundary, which will probably
        result in a string shorter than chars.
    truncate -- String to add to the end.
    """
    if strip_html:
        text = strip_tags(text)
    text = text.replace('\n', ' ').replace('\r', '')
    text = ' '.join(text.split())
    if at_word_boundary:
        if len(text) > chars:
            text = text[:chars].rsplit(' ', 1)[0] + truncate
    else:
        text = Truncator(text).chars(chars, html=False, truncate=truncate)
    return text