Ruby IMAP自上次检查后"更改"

Question

我正在使用Ruby和Rails开发IMAP客户端.我可以成功导入邮件,邮箱等...但是,在初始导入后,如何检测自上次同步以来发生的任何更改？

目前,我将UID和UID有效值存储在数据库中,进行比较,并进行适当的搜索.这有效,但它不会检测已删除的消息或对消息标志的更改等.

我是否必须每次都提取所有消息以检测这些更改？其他IMAP客户如何快速完成(即Apple Mail和Postbox).我的脚本每个帐户已经花了10多秒,只有很少的电子邮件地址:

# select ourself as the current mailbox
@imap_connection.examine(self.location)

# grab all new messages and update them in the database
# if the uid's are still valid, we will just fetch the newest UIDs
# otherwise, we need to search when we last synced, which is slower :(
if self.uid_validity.nil? || uid_validity == self.uid_validity
  # for some IMAP servers, if a mailbox is empty, a uid_fetch will fail, so then
  begin
    messages = @imap_connection.uid_fetch(uid_range, ['UID', 'RFC822', 'FLAGS'])
  rescue
    # gmail cries if the folder is empty
    uids = @imap_connection.uid_search(['ALL'])
    messages = @imap_connection.uid_fetch(uids, ['UID', 'RFC822', 'FLAGS']) unless uids.empty?
  end

  messages.each do |imap_message|
    Message.create_from_imap!(imap_message, self.id)
  end unless messages.nil?
else
  query = self.last_synced.nil? ? ['All'] : ['SINCE', Net::IMAP.format_datetime(self.last_synced)]
  @imap_connection.search(query).each do |message_id|
    imap_message = @imap_connection.fetch(message_id, ['RFC822', 'FLAGS', 'UID'])[0]

    # don't mark the messages as read
    #@imap_connection.store(message_id, '-FLAGS', [:Seen])

    Message.create_from_imap!(imap_message, self.id)
  end
end

# now assume all UIDs are valid
self.uid_validity = uid_validity

# now remember that we just fetched all those messages
self.last_synced = Time.now
self.save!

Answer 1

Quick Flag Changes Resynchronization(RFC-4551)有一个IMAP扩展.使用此扩展,可以搜索自上次同步以来已更改的所有消息(基于某种时间戳).但是,据我所知,这种扩展并未得到广泛支持.

有一个信息RFC描述了IMAP客户端应如何进行同步(RFC-4549,第4.3节).该文本建议发出以下两个命令:

tag1 UID FETCH <lastseenuid+1>:* <descriptors>
tag2 UID FETCH 1:<lastseenuid> FLAGS

第一个命令用于获取所有未知邮件所需的信息(不知道有多少邮件).第二个命令用于同步已经看过的邮件的标志.

AFAIK这种方法被广泛使用.因此,许多IMAP服务器都包含优化,以便快速提供此信息.通常,网络带宽是限制因素.