IMAP客户端实现中的陷阱

昨天在程序中实现IMAP收件的时候发现好多服务器都收不了，用Ethereal对OE进行监视发现其中在Fetch命令前有idle命令，网上查资料发现：

在rfc2177中补充了里面的关于IDLE命令http://www.faqs.org/rfcs/rfc2177.html

Example: C: A001 SELECT INBOX

S: * FLAGS (Deleted Seen)

S: * 3 EXISTS

S: * 0 RECENT

S: * OK [UIDVALIDITY 1]

S: A001 OK SELECT completed

C: A002 IDLE

S: + idling

...time passes; new mail arrives...

S: * 4 EXISTS

C: DONE

S: A002 OK IDLE terminated

...another client expunges message 2 now...

C: A003 FETCH 4 ALL

S: * 4 FETCH (...)

S: A003 OK FETCH completed

C: A004 IDLE

S: * 2 EXPUNGE

S: * 3 EXISTS

S: + idling

...time passes; another client expunges message 3...

S: * 3 EXPUNGE

S: * 2 EXISTS

...time passes; new mail arrives...

S: * 3 EXISTS

C: DONE

S: A004 OK IDLE terminated

C: A005 FETCH 3 ALL

S: * 3 FETCH (...)

S: A005 OK FETCH completed

C: A006 IDLE