http.py 文件源码

def modified(date=None, etag=None):
    n = set(x.strip('" ') for x in web.ctx.env.get('HTTP_IF_NONE_MATCH', '').split(','))
    m = net.parsehttpdate(web.ctx.env.get('HTTP_IF_MODIFIED_SINCE', '').split(';')[0])
    validate = False
    if etag:
        if '*' in n or etag in n:
            validate = True
    if date and m:
        # we subtract a second because 
        # HTTP dates don't have sub-second precision
        if date-datetime.timedelta(seconds=1) <= m:
            validate = True

    if validate: web.ctx.status = '304 Not Modified'
    return not validate