IMAP4 Extension for Returning MYRIGHTS Information in Extended LIST
draft-murchison-imap-list-myrights-01

Abstract

This document defines an extension to the to IMAP LIST command that allows the client to request the set of rights that the logged-in user has been granted on mailboxes, along with other information typically returned by the LIST command.

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Table of Contents

• 1. Introduction
• 2. Conventions Used in This Document
• 3. MYRIGHTS Return Option to LIST Command
• 4. Examples
• 5. Formal Syntax
• 6. Security Considerations
• 7. Privacy Considerations
• 8. IANA Considerations
• 8.1. Registration of IMAP capability LIST-MYRIGHTS
• 8.2. Registration of LIST-EXTENDED option MYRIGHTS
• 9. Acknowledgments
• 10. References
• 10.1. Normative References
• 10.2. Informative References
• Appendix A. Change History (To be removed by RFC Editor before publication)
• Authors' Addresses

1. Introduction

IMAP clients typically fetch the set of rights granted on mailboxes so they can expose the allowed functionality to the logged-in user. In order to do that, the client is forced to issue a LIST or LSUB command to list all available mailboxes, followed by a MYRIGHTS command for each mailbox found. This document defines an extension to the to IMAP LIST command that is identified by the capability string "LIST-MYRIGHTS". The LIST-MYRIGHTS extension allows the client to request the set of rights that the logged-in user has been granted on mailboxes, along with other information typically returned by the LIST command.

2. Conventions Used in This Document

In examples, "C:" indicates lines sent by a client that is connected to a server. "S:" indicates lines sent by the server to the client.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

3. MYRIGHTS Return Option to LIST Command

[RFC4314] defines the MYRIGHTS command which is used by an IMAP client to determine the set of rights that the logged-in user has been granted on a given mailbox. Frequently, a client will have to look up the rights for some or all of the mailboxes returned by the LIST command. Doing so in multiple MYRIGHTS commands wastes bandwidth and can degrade performance if the client does not pipeline the requests.

This document extends the LIST command with a new return option, "MYRIGHTS", which allows the client to request all of the desired information in a single command. For each listable mailbox matching the list pattern and selection options, the server MUST return an untagged LIST response followed by an untagged MYRIGHTS response containing the set of rights granted to the logged-in user.

If the server is unable to look up the set of rights for a given mailbox, it MAY drop the corresponding MYRIGHTS reply. In such a situation, the LIST command would still return a tagged OK reply.

4. Examples

In this example the "bar" mailbox doesn't exist, so it has no MYRIGHTS reply.

C: A01 LIST "" % RETURN (MYRIGHTS)
S: * LIST () "."  "INBOX"
S: * MYRIGHTS "INBOX" lrswipkxtecdan
S: * LIST () "." "foo"
S: * MYRIGHTS "foo" lrs
S: * LIST (\NonExistent) "." "bar"
S: A01 OK List completed.

In this example the LIST reply for the "foo" mailbox is returned because it has matching children, but no MYRIGHTS reply is returned because "foo" itself doesn't match the selection criteria.

C: A02 LIST (SUBSCRIBED RECURSIVEMATCH) "" % RETURN (MYRIGHTS)
S: * LIST (\Subscribed) "."  "INBOX"
S: * MYRIGHTS "INBOX" lrswipkxtecdan
S: * LIST () "." "foo" (CHILDINFO ("SUBSCRIBED"))
S: A02 OK List completed.

5. Formal Syntax

The following syntax specification uses the augmented Backus-Naur Form (BNF) as described in [RFC5234]. Terms not defined here are taken from [RFC5258].

return-option =/ "MYRIGHTS"

6. Security Considerations

This specification does not introduce any additional security concerns beyond those described in [RFC5258].

7. Privacy Considerations

This specification does not introduce any additional privacy concerns beyond those described in [RFC4314].

8. IANA Considerations

8.1. Registration of IMAP capability LIST-MYRIGHTS

This document defines the "LIST-MYRIGHTS" IMAP capability to be added to the registry defined in Section 12 of [RFC3501].

8.2. Registration of LIST-EXTENDED option MYRIGHTS

This section registers the "MYRIGHTS" option to be added to the registry defined in Section 9 of [RFC5258].

LIST-EXTENDED option name:

MYRIGHTS

LIST-EXTENDED option type:

RETURN

LIST-EXTENDED option description:

Causes the LIST command to return MYRIGHTS responses in addition to LIST responses.

Published specification:

RFC XXXX, Section 3

Security considerations:

RFC XXXX, Section 6

Intended usage:

COMMON

Person and email address to contact for further information:

Kenneth Murchison <murch@andrew.cmu.edu>

Owner/Change controller:

IESG <iesg@ietf.org>

9. Acknowledgments

This document is based largely on [RFC5819]. The author would like to thank the authors of that document for providing both inspiration and some borrowed text for this document.

10. References

10.1. Normative References

10.2. Informative References

Appendix A. Change History (To be removed by RFC Editor before publication)

Changes in draft-murchison-imap-list-myrights-01:

• Augmented Introduction with mention of "LIST-MYRIGHTS" capability string.
• Minor editorial changes.

Authors' Addresses