IMAP4 Extension for Returning MYRIGHTS Information in Extended LIST
Extracted elements (10)
Prior to this extension, clients were forced to issue LIST or LSUB commands followed by a separate MYRIGHTS command for each mailbox, wasting bandwidth and degrading performance when requests were not pipelined. Combining both into a single LIST command with a MYRIGHTS return option eliminates this round-trip overhead.
If the server is unable to look up the set of rights for a given mailbox, it does not send the MYRIGHTS reply for that mailbox. The "bar" mailbox example illustrates this: a non-existent mailbox receives a LIST response but no MYRIGHTS reply.
Clients SHOULD use a suitable match pattern and/or selection option to limit the set of mailboxes returned to only those in whose rights they are interested, to avoid overloading the server.
For each listable mailbox matching the list pattern and selection options, the server MUST return an untagged LIST response and SHOULD also return an untagged MYRIGHTS response containing the set of rights granted to the logged-in user.
The server MUST NOT send a MYRIGHTS response for a given mailbox before it sends the LIST response for that mailbox, enforcing a strict ordering constraint on the response sequence.
This specification does not introduce any additional privacy concerns beyond those described in RFC 4314 (IMAP4 Access Control List extension).
The LIST-MYRIGHTS extension adds a new "MYRIGHTS" return option to the IMAP LIST command, allowing clients to request mailbox rights alongside other LIST information in a single command. This is identified by the capability string "LIST-MYRIGHTS".
This document registers the "LIST-MYRIGHTS" IMAP capability in the IANA "IMAP Capabilities" registry, and registers the "MYRIGHTS" RETURN option in the IANA "LIST-EXTENDED options" registry.
The extension makes it easier for clients to overload the server by requesting MYRIGHTS information for a large number of mailboxes in one command. Server implementations must ensure they can still serve other IMAP connections and yield execution when necessary during large MYRIGHTS retrievals.
The ABNF extension adds "MYRIGHTS" as a valid return-option in the LIST command syntax: `return-option =/ "MYRIGHTS"`. Terms not defined here are taken from RFC 5258.