def robotsrulesetOfDomain(self, domain):
		'''检查domain是否在数据库中,
			否 --> (False, None)
			是 --> (True, 数据库中存储的robots.txt内容)
		'''
		exist = False
		cur = self.conn.cursor()
		# 是否存在
		cur.execute("SELECT 1 FROM Domains WHERE domain=?", (domain,))
		if cur.fetchone() :
			exist = True
		# 存在的话,结果是什么
		cur.execute("SELECT rules FROM Domains,Rulesets "
			"WHERE domain=? AND Domains.did=Rulesets.did"
			,(domain,) )
		ruleset = cur.fetchone()
		return (exist, ruleset)
def visitdir(self, dir):
        """Decides whether a directory should be visited based on whether it
        has potential matches in it or one of its subdirectories. This is
        based on the match's primary, included, and excluded patterns.

        Returns the string 'all' if the given directory and all subdirectories
        should be visited. Otherwise returns True or False indicating whether
        the given directory should be visited.
        """
        return True