markdown2.py django custom filter

templatetags.py

urlfinder = re.compile('^(http:\/\/\S+)')
urlfinder2 = re.compile('\s(http:\/\/\S+)')
@register.filter('markdownify')
def markdownify(value):
    import feedparser
    import markdown2
    value = urlfinder.sub(r'<\1>', value)
    value = urlfinder2.sub(r' <\1>', value)
    html = markdown2.markdown(value)
    html = feedparser._sanitizeHTML(html, 'utf-8')
    html = html.replace('<a href=', '<a rel="nofollow" href=')
    return safestring.mark_safe(html)
markdownify.is_safe = True