validators.py 文件源码

def urlify(s, maxlen=80, keep_underscores=False):
    """
    Converts incoming string to a simplified ASCII subset.
    if (keep_underscores): underscores are retained in the string
    else: underscores are translated to hyphens (default)
    """
    s = to_unicode(s)                     # to unicode
    s = s.lower()                         # to lowercase
    s = unicodedata.normalize('NFKD', s)  # replace special characters
    s = to_native(s, charset='ascii', errors='ignore')       # encode as ASCII
    s = re.sub('&\w+?;', '', s)           # strip html entities
    if keep_underscores:
        s = re.sub('\s+', '-', s)         # whitespace to hyphens
        s = re.sub('[^\w\-]', '', s)
        # strip all but alphanumeric/underscore/hyphen
    else:
        s = re.sub('[\s_]+', '-', s)      # whitespace & underscores to hyphens
        s = re.sub('[^a-z0-9\-]', '', s)  # strip all but alphanumeric/hyphen
    s = re.sub('[-_][-_]+', '-', s)       # collapse strings of hyphens
    s = s.strip('-')                      # remove leading and trailing hyphens
    return s[:maxlen]                     # enforce maximum length