draft-ietf-extra-imap-objectid-03.txt   draft-ietf-extra-imap-objectid-04.txt 
EXTRA B. Gondwana, Ed. EXTRA B. Gondwana, Ed.
Internet-Draft FastMail Internet-Draft FastMail
Updates: 3501 (if approved) May 28, 2018 Updates: 3501 (if approved) July 17, 2018
Intended status: Standards Track Intended status: Standards Track
Expires: November 29, 2018 Expires: January 18, 2019
IMAP Extension for object identifiers IMAP Extension for object identifiers
draft-ietf-extra-imap-objectid-03 draft-ietf-extra-imap-objectid-04
Abstract Abstract
This document updates RFC3501 (IMAP4rev1) with persistent identifiers This document updates RFC3501 (IMAP4rev1) with persistent identifiers
on mailboxes and messages to allow clients to more efficiently re-use on mailboxes and messages to allow clients to more efficiently re-use
cached data when resources have changed location on the server. cached data when resources have changed location on the server.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 29, 2018. This Internet-Draft will expire on January 18, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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6. New Filters on SEARCH command . . . . . . . . . . . . . . . . 9 6. New Filters on SEARCH command . . . . . . . . . . . . . . . . 9
7. Formal syntax . . . . . . . . . . . . . . . . . . . . . . . . 9 7. Formal syntax . . . . . . . . . . . . . . . . . . . . . . . . 9
8. Implementation considerations . . . . . . . . . . . . . . . . 10 8. Implementation considerations . . . . . . . . . . . . . . . . 10
8.1. Assigning object identifiers . . . . . . . . . . . . . . 10 8.1. Assigning object identifiers . . . . . . . . . . . . . . 10
8.2. Interaction with special cases . . . . . . . . . . . . . 11 8.2. Interaction with special cases . . . . . . . . . . . . . 11
8.3. Client usage . . . . . . . . . . . . . . . . . . . . . . 11 8.3. Client usage . . . . . . . . . . . . . . . . . . . . . . 11
9. Future considerations . . . . . . . . . . . . . . . . . . . . 11 9. Future considerations . . . . . . . . . . . . . . . . . . . . 11
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
11. Security Considerations . . . . . . . . . . . . . . . . . . . 12 11. Security Considerations . . . . . . . . . . . . . . . . . . . 12
12. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 12. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
12.1. draft-ietf-extra-imap-objectid-03 . . . . . . . . . . . 12 12.1. draft-ietf-extra-imap-objectid-04 . . . . . . . . . . . 12
12.2. draft-ietf-extra-imap-objectid-02 . . . . . . . . . . . 12 12.2. draft-ietf-extra-imap-objectid-03 . . . . . . . . . . . 13
12.3. draft-ietf-extra-imap-objectid-01 . . . . . . . . . . . 12 12.3. draft-ietf-extra-imap-objectid-02 . . . . . . . . . . . 13
12.4. draft-ietf-extra-imap-objectid-00 . . . . . . . . . . . 13 12.4. draft-ietf-extra-imap-objectid-01 . . . . . . . . . . . 13
12.5. draft-ietf-extra-imap-uniqueid-00 . . . . . . . . . . . 13 12.5. draft-ietf-extra-imap-objectid-00 . . . . . . . . . . . 14
12.6. draft-gondwana-imap-uniqueid-01 . . . . . . . . . . . . 13 12.6. draft-ietf-extra-imap-uniqueid-00 . . . . . . . . . . . 14
12.7. draft-gondwana-imap-uniqueid-00 . . . . . . . . . . . . 14 12.7. draft-gondwana-imap-uniqueid-01 . . . . . . . . . . . . 14
12.8. draft-gondwana-imap-uniqueid-00 . . . . . . . . . . . . 14
13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
13.1. Appendix 1: ideas for implementing object identifiers . 14 13.1. Appendix 1: ideas for implementing object identifiers . 15
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
14.1. Normative References . . . . . . . . . . . . . . . . . . 15 14.1. Normative References . . . . . . . . . . . . . . . . . . 15
14.2. Informative References . . . . . . . . . . . . . . . . . 15 14.2. Informative References . . . . . . . . . . . . . . . . . 16
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 16 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Introduction
IMAP stores are often used by many clients. Each client may cache IMAP stores are often used by many clients. Each client may cache
data from the server so that they don't need to re-download data from the server so that they don't need to re-download
information. [RFC3501] defines that a mailbox can be uniquely information. [RFC3501] defines that a mailbox can be uniquely
referenced by its name and UIDVALIDITY, and a message within that referenced by its name and UIDVALIDITY, and a message within that
mailbox can be uniquely referenced by its mailbox (name + mailbox can be uniquely referenced by its mailbox (name +
UIDVALIDITY) and UID. The triple of mailbox name, UIDVALIDITY and UIDVALIDITY) and UID. The triple of mailbox name, UIDVALIDITY and
UID is guaranteed to be immutable. UID is guaranteed to be immutable.
[RFC4315] defines a COPYUID response which allows a client which [RFC4315] defines a COPYUID response which allows a client which
copies messages to know the mapping between the UIDs in the source copies messages to know the mapping between the UIDs in the source
and destination mailboxes, and hence update its local cache. and destination mailboxes, and hence update its local cache.
If a mailbox is successfully renamed, the client knows that the same If a mailbox is successfully renamed by a client, that client will
messages exist in the destination mailbox name as previously existed know that the same messages exist in the destination mailbox name as
in the source mailbox name. previously existed in the source mailbox name.
The result is that the client which copies (or [RFC6851] moves) The result is that the client which copies (or [RFC6851] moves)
messages or renames a mailbox can update its local cache, but any messages or renames a mailbox can update its local cache, but any
other client connected to the same store can not know with certainty other client connected to the same store can not know with certainty
that the messages are identical, and so will re-download everything. that the messages are identical, and so will re-download everything.
This extension adds new properties to a message (EMAILID) and mailbox This extension adds new properties to a message (EMAILID) and mailbox
(MAILBOXID) which allow a client to quickly identify messages or (MAILBOXID) which allow a client to quickly identify messages or
mailboxes which have been renamed by another client. mailboxes which have been renamed by another client.
This extension also adds an optional thread identifier (THREADID) to This extension also adds an optional thread identifier (THREADID) to
messages, which can be used by the server to indicate messages which messages, which can be used by the server to indicate messages which
it has identified to be related. it has identified to be related. A server that does not implement
threading will return NIL to all requests for THREADID.
2. Conventions Used In This Document 2. Conventions Used In This Document
In examples, "C:" indicates lines sent by a client that is connected 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. to a server. "S:" indicates lines sent by the server to the client.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119] when they document are to be interpreted as described in [RFC2119] when they
appear in ALL CAPS. These words may also appear in this document in appear in ALL CAPS. These words may also appear in this document in
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3. CAPABILITY Identification 3. CAPABILITY Identification
IMAP servers that support this extension MUST include "OBJECTID" in IMAP servers that support this extension MUST include "OBJECTID" in
the response list to the CAPABILITY command. the response list to the CAPABILITY command.
4. MAILBOXID object identifier 4. MAILBOXID object identifier
The MAILBOXID is a server-allocated unique identifer for each The MAILBOXID is a server-allocated unique identifer for each
mailbox. mailbox.
The server SHOULD return the same MAILBOXID for a server with the The server MUST return the same MAILBOXID for a mailbox with the same
same mailbox name and UIDVALIDITY. This is almost MUST, but weakened name and UIDVALIDITY.
to allow for the possibility of loss of OBJECTID data during disaster
recovery while still keeping the name and UIDVALIDITY the same.
The server MUST NOT report the same MAILBOXID for two mailboxes at The server MUST NOT report the same MAILBOXID for two mailboxes at
the same time. the same time.
The server MUST NOT reuse the same MAILBOXID for a mailbox which does The server MUST NOT reuse the same MAILBOXID for a mailbox which does
not obey all the invarients that [RFC3501] defines for a mailbox not obey all the invarients that [RFC3501] defines for a mailbox
which does not change name or UIDVALIDITY. which does not change name or UIDVALIDITY.
The server MAY choose to create a MAILBOXID value in a way that does The server SHOULD NOT change MAILBOXID when renaming a folder, as
not survive RENAME (e.g. a digest of name + uidvalidity could be this loses the main benefit of having a unique identifier.
used), however the client then loses the major benefit of having an
identifier.
4.1. New response code for CREATE 4.1. New response code for CREATE
This document extends the CREATE command to have the response code This document extends the CREATE command to have the response code
MAILBOXID on successful mailbox creation. MAILBOXID on successful mailbox creation.
A server advertising the OBJECTID capability MUST include the A server advertising the OBJECTID capability MUST include the
MAILBOXID response code in the tagged OK response to all successful MAILBOXID response code in the tagged OK response to all successful
CREATE commands. CREATE commands.
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S: * LIST (\HasNoChildren) "." INBOX S: * LIST (\HasNoChildren) "." INBOX
S: * STATUS INBOX (MAILBOXID (Ff8e3ead4-9389-4aff-adb1-d8d89efd8cbf)) S: * STATUS INBOX (MAILBOXID (Ff8e3ead4-9389-4aff-adb1-d8d89efd8cbf))
S: * LIST (\HasNoChildren) "." bar S: * LIST (\HasNoChildren) "." bar
S: * STATUS bar (MAILBOXID (F6352ae03-b7f5-463c-896f-d8b48ee3)) S: * STATUS bar (MAILBOXID (F6352ae03-b7f5-463c-896f-d8b48ee3))
S: * LIST (\HasNoChildren) "." renamed S: * LIST (\HasNoChildren) "." renamed
S: * STATUS renamed (MAILBOXID (F2212ea87-6097-4256-9d51-71338625)) S: * STATUS renamed (MAILBOXID (F2212ea87-6097-4256-9d51-71338625))
S: 11 OK Completed (0.001 secs 3 calls) S: 11 OK Completed (0.001 secs 3 calls)
5. EMAILID object identifier and THREADID correlator 5. EMAILID object identifier and THREADID correlator
This document defines the data items EMAILID and THREADID on
messages.
5.1. EMAILID identifier for identical messages 5.1. EMAILID identifier for identical messages
The EMAILID data item is an objectid which uniquely identifies the The EMAILID data item is an objectid which uniquely identifies the
content of a single message. Anything which must remain immutable on content of a single message. Anything which must remain immutable on
a {name, uidvalidity, uid} triple must also be the same between a {name, uidvalidity, uid} triple must also be the same between
messages with the same EMAILID. messages with the same EMAILID.
The server SHOULD return the same EMAILID for the same UID triple. The server MUST return the same EMAILID for the same triple, hence
As with MAILBOXID above, this is almost a MUST, but allows for the EMAILID is immutable.
possibility of loss of OBJECTID data in disaster recovery without
having to change UIDVALIDITY.
The server SHOULD return the same EMAILID for the exact same message The server MUST return the same EMAILID as the source message for the
content in different folders after a COPY or [RFC6851] MOVE command. matching destination message in the COPYUID pairing after a COPY or
[RFC6851] MOVE command.
The server MAY assign the same EMAILID as an existing message upon The server MAY assign the same EMAILID as an existing message upon
APPEND if it detects that the new message has exactly identical APPEND (e.g. if it detects that the new message has exactly identical
content to that existing message. content to that of an existing message)
NOTE: EMAILID only identifies the immutable content of the message.
In particular, it is possible for different messages with the same
EMAILID to have different keywords. This document does not specify a
way to STORE by EMAILID.
5.2. THREADID identifer for related messages 5.2. THREADID identifer for related messages
The THREADID data item is an objectid which uniquely identifies a set The THREADID data item is an objectid which uniquely identifies a set
of messages which the server believes should be grouped together when of messages which the server believes should be grouped together when
presented. presented.
THREADID calculation is generally based on some combination of THREADID calculation is generally based on some combination of
References, In-Reply-To and Subject, but the exact logic is left up References, In-Reply-To and Subject, but the exact logic is left up
to the server implementation. [RFC5256] describes some algorithms to the server implementation. [RFC5256] describes some algorithms
that MAY be used, however this specfication does not mandate any that could be used, however this specfication does not mandate any
particular strategy. particular strategy.
The server MUST return the same THREADID for all messages with the The server MUST return the same THREADID for all messages with the
same EMAILID. same EMAILID.
The server SHOULD return the same THREADID for related messages even The server SHOULD return the same THREADID for related messages even
if they are in different mailboxes. if they are in different mailboxes.
THREADID is optional, if the server is unable to calculate THREADID is optional, if the server doesn't support THREADID or is
relationships between messages, it MUST return NIL to in all FETCH unable to calculate relationships between messages, it MUST return
responses for the THREADID data item, and a SEARCH for THREADID MUST NIL to all FETCH responses for the THREADID data item, and a SEARCH
NOT match any messages. for THREADID MUST NOT match any messages.
The server MAY use the same objectid value for both EMAILID and The server MUST NOT use the same objectid value for both EMAILIDs and
THREADID, for example the THREADID could be the EMAILID of the first THREADIDs. If they are stored with the same value internally, the
message that the server has seen in each thread. server can generate prefixed values (as shown in the examples below
with M and T prefixes) to avoid clashes.
5.3. New Message Data Items in FETCH and UID FETCH Commands 5.3. New Message Data Items in FETCH and UID FETCH Commands
This document defines two FETCH items: This document defines two FETCH items:
Syntax: EMAILID Syntax: EMAILID
The EMAILID message data item causes the server to return EMAILID The EMAILID message data item causes the server to return EMAILID
FETCH response data items. FETCH response data items.
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insensitive. The use of upper- or lowercase characters to define insensitive. The use of upper- or lowercase characters to define
token strings is for editorial clarity only. Implementations MUST token strings is for editorial clarity only. Implementations MUST
accept these strings in a case-insensitive fashion. accept these strings in a case-insensitive fashion.
capability =/ "OBJECTID" capability =/ "OBJECTID"
fetch-att =/ "EMAILID" / "THREADID" fetch-att =/ "EMAILID" / "THREADID"
fetch-emailid-resp = "EMAILID" SP "(" objectid ")" ; follows tagged- fetch-emailid-resp = "EMAILID" SP "(" objectid ")" ; follows tagged-
ext production from [RFC4466] ext production from [RFC4466]
fetch-threadid-resp = "THREADID" SP "(" objectid ")" / "THREADID NIL fetch-threadid-resp = "THREADID" SP "(" objectid ")" / "THREADID" NIL
; follows tagged-ext production from [RFC4466] ; follows tagged-ext production from [RFC4466]
objectid = 1*255(ALPHA / DIGIT / "_" / "-") ; characters in object objectid = 1*255(ALPHA / DIGIT / "_" / "-") ; characters in object
identifiers are case ; significant identifiers are case ; significant
resp-text-code =/ "MAILBOXID" SP "(" objectid ")" ; incorporated resp-text-code =/ "MAILBOXID" SP "(" objectid ")" ; incorporated
before the expansion rule of ; atom [SP 1*<any TEXT-CHAR except "]">] before the expansion rule of ; atom [SP 1*<any TEXT-CHAR except "]">]
; that appears in [RFC3501] ; that appears in [RFC3501]
search-key =/ "EMAILID" SP objectid / "THREADID" SP objectid search-key =/ "EMAILID" SP objectid / "THREADID" SP objectid
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o ids which contain only digits o ids which contain only digits
o ids which differ only by ASCII case (A vs a) o ids which differ only by ASCII case (A vs a)
o the specific sequence of 3 characters NIL o the specific sequence of 3 characters NIL
A good solution to these issues is to prefix every ID with a single A good solution to these issues is to prefix every ID with a single
alphabetical character. alphabetical character.
8.2. Interaction with special cases 8.2. Interaction with special cases
The case of RENAME INBOX may need special handling for unique ids. The case of RENAME INBOX may need special handling, as it has special
behaviour as defined in [RFC3501] section 6.3.5.
It is advisable (though not required) to have MAILBOXID be globally It is advisable (though not required) to have MAILBOXID be globally
unique, but it is only required to be unique within messages offered unique, but it is only required to be unique within messages offered
to a single client login to a single server hostname. For example, a to a single client login to a single server hostname. For example, a
proxy which aggregates multiple independent servers MUST NOT proxy which aggregates multiple independent servers MUST NOT
advertise the OBJECTID capability unless it can guarantee that the advertise the OBJECTID capability unless it can guarantee that
backends will not use the same identifiers for different objects. different objects will never use the same identifiers, even if
backend object collide.
8.3. Client usage 8.3. Client usage
Servers that implement both RFC 6154 and this specification SHOULD Servers that implement both RFC 6154 and this specification SHOULD
optimize their execution of command like UID SEARCH OR EMAILID 1234 optimize their execution of command like UID SEARCH OR EMAILID 1234
EMAILID 4321. EMAILID 4321.
Clients can assume that searching the all-mail mailbox using OR/ Clients can assume that searching the all-mail mailbox using OR/
EMAILID or OR/THREADID is a fast way to find messages again if some EMAILID or OR/THREADID is a fast way to find messages again if some
other client has moved them out of the mailbox where they were other client has moved them out of the mailbox where they were
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data. data.
9. Future considerations 9. Future considerations
This extension is intentionally defined to be compatible with the This extension is intentionally defined to be compatible with the
data model in [I-D.ietf-jmap-mail]. data model in [I-D.ietf-jmap-mail].
A future extension could be proposed to give a way to SELECT a A future extension could be proposed to give a way to SELECT a
mailbox by MAILBOXID rather than name. mailbox by MAILBOXID rather than name.
A future extension to [RFC5228] could allow fileinto by MAILBOXID
rather than name.
An extension to allow fetching message content directly via EMAILID An extension to allow fetching message content directly via EMAILID
and message listings by THREADID could be proposed. and message listings by THREADID could be proposed.
10. IANA Considerations 10. IANA Considerations
IANA is requested to add "OBJECTID" to the "IMAP Capabilities" IANA is requested to add "OBJECTID" to the "IMAP Capabilities"
registry located at <http://www.iana.org/assignments/imap- registry located at <http://www.iana.org/assignments/imap-
capabilities>. capabilities>.
IANA is requested to add "MAILBOXID" to the "IMAP Response Codes" IANA is requested to add "MAILBOXID" to the "IMAP Response Codes"
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codes> with a Reference of [[THIS RFC]]. codes> with a Reference of [[THIS RFC]].
11. Security Considerations 11. Security Considerations
It is strongly advised that servers generate OBJECTIDs which are safe It is strongly advised that servers generate OBJECTIDs which are safe
to use as filesystem names, and unlikely to be auto-detected as to use as filesystem names, and unlikely to be auto-detected as
numbers. See implementation considerations. numbers. See implementation considerations.
If a digest is used for ID generation, it must have a collision If a digest is used for ID generation, it must have a collision
resistent property, so server implementations are advised to monitor resistent property, so server implementations are advised to monitor
current security research and choose secure digests. current security research and choose secure digests. As the IDs are
generated by the server, it will be possible to migrate to a new hash
by just creating new IDs with the new algorithm. This is
particularly true if a prefix is used on each ID, which can be
changed when the algorithm changes.
The use of a digest for ID generation may be used as proof that a The use of a digest for ID generation may be used as proof that a
particular sequence of bytes was seen by the server. particular sequence of bytes was seen by the server, however this is
only a risk if IDs are leaked to clients who don't have permission to
fetch the data directly. Servers that are expected to handle highly
sensitive data should consider using a ID generation mechanism which
doesn't derive from a digest.
See also the security considerations in [RFC3501] section 11.
12. Changes 12. Changes
To be removed by the editor before publication To be removed by the editor before publication
12.1. draft-ietf-extra-imap-objectid-03 12.1. draft-ietf-extra-imap-objectid-04
o described NIL THREADID in more detail (ad review)
o made RFC5256 a normative reference (ad review)
o fixed ABNF missing quote (ad review)
o documented hash upgrade process (ad review)
o referenced RFC3501 for INBOX rename (ad review)
o referenced RFC3501 security considerations (secdir review)
o turned mealy-mouthed "SHOULDs" in to "MUSTs" on immutability
(genart review)
o remove suggested algorithms which are no longer legitimate (genart
review)
o updated proxy advice to suggest rewriting ids (genart review)
o fixed minor gramatical issues (genart review)
o required that EMAILID and THREADID are not identical (own
decision)
12.2. draft-ietf-extra-imap-objectid-03
o added RFC3501 to Abstract o added RFC3501 to Abstract
o updated [[THIS RFC]] to not fail idnits o updated [[THIS RFC]] to not fail idnits
o changed jmap-mail to be informative rather than normative o changed jmap-mail to be informative rather than normative
o shortened IDs to stop wrapping and outdents in IMAP examples o shortened IDs to stop wrapping and outdents in IMAP examples
12.2. draft-ietf-extra-imap-objectid-02 12.3. draft-ietf-extra-imap-objectid-02
o added "Client usage" section o added "Client usage" section
12.3. draft-ietf-extra-imap-objectid-01 12.4. draft-ietf-extra-imap-objectid-01
o added "updates" for RFC3501 o added "updates" for RFC3501
o fixed domains in thread example o fixed domains in thread example
o described threading in more detail o described threading in more detail
o added IANA request for Response Code o added IANA request for Response Code
o clarified RFC2119 references o clarified RFC2119 references
o simplified some waffle in wording o simplified some waffle in wording
o added security consideration to choose good digest o added security consideration to choose good digest
o added MAILBOXID-UID suggestion for EMAILID generation o added MAILBOXID-UID suggestion for EMAILID generation
skipping to change at page 13, line 16 skipping to change at page 14, line 5
o clarified RFC2119 references o clarified RFC2119 references
o simplified some waffle in wording o simplified some waffle in wording
o added security consideration to choose good digest o added security consideration to choose good digest
o added MAILBOXID-UID suggestion for EMAILID generation o added MAILBOXID-UID suggestion for EMAILID generation
o updated ABNF normative reference to RFC5234 o updated ABNF normative reference to RFC5234
12.4. draft-ietf-extra-imap-objectid-00 12.5. draft-ietf-extra-imap-objectid-00
o renamed draft to be objectid rather than uniqueid o renamed draft to be objectid rather than uniqueid
o renamed UNIQUEID (capability) to OBJECTID o renamed UNIQUEID (capability) to OBJECTID
o restricted objectid to 64 safe characters o restricted objectid to 64 safe characters
o added security considerations and advice about choosing objectid o added security considerations and advice about choosing objectid
o wrapped all responses in () for RFC4466 compatibility o wrapped all responses in () for RFC4466 compatibility
o signifiant rewrite of all sections o signifiant rewrite of all sections
12.5. draft-ietf-extra-imap-uniqueid-00 12.6. draft-ietf-extra-imap-uniqueid-00
o renamed draft to be an EXTRA document o renamed draft to be an EXTRA document
o added example for LIST RETURN STATUS o added example for LIST RETURN STATUS
o started work on ABNF o started work on ABNF
o attempted to add response codes for EMAILID and THREADID o attempted to add response codes for EMAILID and THREADID
12.6. draft-gondwana-imap-uniqueid-01 12.7. draft-gondwana-imap-uniqueid-01
o renamed UNIQUEID (status item) to MAILBOXID o renamed UNIQUEID (status item) to MAILBOXID
o renamed MSGID to EMAILID o renamed MSGID to EMAILID
o renamed THRID to THREADID o renamed THRID to THREADID
o added TODO section o added TODO section
12.7. draft-gondwana-imap-uniqueid-00 12.8. draft-gondwana-imap-uniqueid-00
o initial upload with names UNIQUEID/MSGID/THRID o initial upload with names UNIQUEID/MSGID/THRID
13. Acknowledgments 13. Acknowledgments
The EXTRA working group at IETF. In particular feedback from Arnt The EXTRA working group at IETF. In particular feedback from Arnt
Gulbrandsen, Brandon Long, Chris Newman and Josef Sipek. Gulbrandsen, Brandon Long, Chris Newman and Josef Sipek.
The Gmail X-GM-THRID and X-GM-MSGID implementation as currently The Gmail X-GM-THRID and X-GM-MSGID implementation as currently
defined at <https://developers.google.com/gmail/imap/imap- defined at <https://developers.google.com/gmail/imap/imap-
extensions>. extensions>.
Dovecot X-GUID implementation. Dovecot X-GUID implementation.
13.1. Appendix 1: ideas for implementing object identifiers 13.1. Appendix 1: ideas for implementing object identifiers
Ideas for implementing MAILBOXID: Ideas for calculating MAILBOXID:
o Digest of (MailboxName/UIDVALIDITY) - not kept when renaming, but
is guaranteed unique and doesn't require storage.
o [RFC4122] UUID o [RFC4122] UUID
o Server assigned sequence number (guaranteed not to be reused) o Server assigned sequence number (guaranteed not to be reused)
Ideas for implementing EMAILID: Ideas for implementing EMAILID:
o Digest of (MailboxName/UIDVALIDITY/UID) - is not kept when copying
messages, but is guaranteed unique and doesn't require storage.
o Concatenation of MAILBOXID-UID - for servers which store MAILBOXID
but not EMAILID.
o Digest of message content (RFC822 bytes) - expensive unless cached o Digest of message content (RFC822 bytes) - expensive unless cached
o [RFC4122] UUID o [RFC4122] UUID
o Server assigned sequence number (guaranteed not to be reused) o Server assigned sequence number (guaranteed not to be reused)
Ideas for implementing THREADID: Ideas for implementing THREADID:
o Derive from EMAILID of first seen message in the thread. o Derive from EMAILID of first seen message in the thread.
skipping to change at page 15, line 30 skipping to change at page 16, line 9
<https://www.rfc-editor.org/info/rfc3501>. <https://www.rfc-editor.org/info/rfc3501>.
[RFC4315] Crispin, M., "Internet Message Access Protocol (IMAP) - [RFC4315] Crispin, M., "Internet Message Access Protocol (IMAP) -
UIDPLUS extension", RFC 4315, DOI 10.17487/RFC4315, UIDPLUS extension", RFC 4315, DOI 10.17487/RFC4315,
December 2005, <https://www.rfc-editor.org/info/rfc4315>. December 2005, <https://www.rfc-editor.org/info/rfc4315>.
[RFC4466] Melnikov, A. and C. Daboo, "Collected Extensions to IMAP4 [RFC4466] Melnikov, A. and C. Daboo, "Collected Extensions to IMAP4
ABNF", RFC 4466, DOI 10.17487/RFC4466, April 2006, ABNF", RFC 4466, DOI 10.17487/RFC4466, April 2006,
<https://www.rfc-editor.org/info/rfc4466>. <https://www.rfc-editor.org/info/rfc4466>.
[RFC5228] Guenther, P., Ed. and T. Showalter, Ed., "Sieve: An Email
Filtering Language", RFC 5228, DOI 10.17487/RFC5228,
January 2008, <https://www.rfc-editor.org/info/rfc5228>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008, DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>. <https://www.rfc-editor.org/info/rfc5234>.
[RFC5256] Crispin, M. and K. Murchison, "Internet Message Access
Protocol - SORT and THREAD Extensions", RFC 5256,
DOI 10.17487/RFC5256, June 2008,
<https://www.rfc-editor.org/info/rfc5256>.
[RFC5819] Melnikov, A. and T. Sirainen, "IMAP4 Extension for [RFC5819] Melnikov, A. and T. Sirainen, "IMAP4 Extension for
Returning STATUS Information in Extended LIST", RFC 5819, Returning STATUS Information in Extended LIST", RFC 5819,
DOI 10.17487/RFC5819, March 2010, DOI 10.17487/RFC5819, March 2010,
<https://www.rfc-editor.org/info/rfc5819>. <https://www.rfc-editor.org/info/rfc5819>.
[RFC6851] Gulbrandsen, A. and N. Freed, Ed., "Internet Message [RFC6851] Gulbrandsen, A. and N. Freed, Ed., "Internet Message
Access Protocol (IMAP) - MOVE Extension", RFC 6851, Access Protocol (IMAP) - MOVE Extension", RFC 6851,
DOI 10.17487/RFC6851, January 2013, DOI 10.17487/RFC6851, January 2013,
<https://www.rfc-editor.org/info/rfc6851>. <https://www.rfc-editor.org/info/rfc6851>.
14.2. Informative References 14.2. Informative References
[I-D.ietf-jmap-mail] [I-D.ietf-jmap-mail]
Jenkins, N., "JMAP for Mail", draft-ietf-jmap-mail-05 Jenkins, N., "JMAP for Mail", draft-ietf-jmap-mail-06
(work in progress), May 2018. (work in progress), July 2018.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122, Unique IDentifier (UUID) URN Namespace", RFC 4122,
DOI 10.17487/RFC4122, July 2005, DOI 10.17487/RFC4122, July 2005,
<https://www.rfc-editor.org/info/rfc4122>. <https://www.rfc-editor.org/info/rfc4122>.
[RFC5256] Crispin, M. and K. Murchison, "Internet Message Access
Protocol - SORT and THREAD Extensions", RFC 5256,
DOI 10.17487/RFC5256, June 2008,
<https://www.rfc-editor.org/info/rfc5256>.
Author's Address Author's Address
Bron Gondwana (editor) Bron Gondwana (editor)
FastMail FastMail
Level 2, 114 William St Level 2, 114 William St
Melbourne VIC 3000 Melbourne VIC 3000
Australia Australia
Email: brong@fastmailteam.com Email: brong@fastmailteam.com
URI: https://www.fastmail.com URI: https://www.fastmail.com
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