IMAP - 由Yahoo X-YMailISG检索邮件

Question

对于所有传入的Yahoo邮件，X-YMailISG是一个可以检索的传入邮件ID邮件。我想知道这在IMAP中是否可行，或者该字段是否完全用于其他内容？

Answer 1

从RFC 3501第6.4.4节开始，您可以使用SEARCH或UID SEARCH与HEADER限定符一起查找该邮件的标识符。

引用：

HEADER <field-name> <string>
         Messages that have a header with the specified field-name (as
         defined in [RFC-2822]) and that contains the specified string
         in the text of the header (what comes after the colon).  If the
         string to search is zero-length, this matches all messages that
         have a header line with the specified field-name regardless of
         the contents.