filters.py 文件源码

def autolink(text, trim_url_limit=None, nofollow=False):
    """
    Converts any URLs in text into clickable links. Works on http://, https:// and
    www. links. Links can have trailing punctuation (periods, commas, close-parens)
    and leading punctuation (opening parens) and it'll still do the right thing.

    If trim_url_limit is not None, the URLs in link text will be limited to
    trim_url_limit characters.

    If nofollow is True, the URLs in link text will get a rel="nofollow" attribute.
    """
    trim_url = lambda x, limit=trim_url_limit: limit is not None and (x[:limit] + (len(x) >=limit and '...' or ''))  or x
    words = word_split_re.split(text)
    nofollow_attr = nofollow and ' rel="nofollow"' or ''
    for i, word in enumerate(words):
        match = punctuation_re.match(word)
        if match:
            lead, middle, trail = match.groups()
            if middle.startswith('www.') or ('@' not in middle and not middle.startswith('http://') and not middle.startswith('https://') and \
                    len(middle) > 0 and middle[0] in string.letters + string.digits and \
                    (middle.endswith('.org') or middle.endswith('.net') or middle.endswith('.com'))):
                middle = '<a href="http://%s"%s target="_blank">%s</a>' % (middle, nofollow_attr, trim_url(middle))
            if middle.startswith('http://') or middle.startswith('https://'):
                middle = '<a href="%s"%s target="_blank">%s</a>' % (middle, nofollow_attr, trim_url(middle))
            if '@' in middle and not middle.startswith('www.') and not ':' in middle \
                and simple_email_re.match(middle):
                middle = '<a href="mailto:%s">%s</a>' % (middle, middle)
            if lead + middle + trail != word:
                words[i] = lead + middle + trail
    return ''.join(words)


# auto convert img.ly/abcd links to image tags