JMAP Blob management extension
draft-ietf-jmap-blob-00
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (jmap WG) | |
|---|---|---|---|
| Author | Bron Gondwana | ||
| Last updated | 2021-07-11 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html xml htmlized pdfized bibtex | ||
| Stream | WG state | WG Document | |
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| IESG | IESG state | I-D Exists | |
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draft-ietf-jmap-blob-00
JMAP B. Gondwana, Ed.
Internet-Draft Fastmail
Updates: 8620 (if approved) 12 July 2021
Intended status: Standards Track
Expires: 13 January 2022
JMAP Blob management extension
draft-ietf-jmap-blob-00
Abstract
The JMAP base protocol (RFC8620) provides the ability to upload and
download arbitrary binary data via HTTP PUT and GET on defined
endpoint. This binary data is called a "Blob".
This extension adds additional ways to create and access Blobs, by
making inline method calls within a standard JMAP request.
This extension also adds a reverse lookup mechanism to discover where
blobs are referenced within other datatypes.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 13 January 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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and restrictions with respect to this document. Code Components
extracted from this document must include Simplified BSD License text
as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used In This Document . . . . . . . . . . . . . . 2
3. Blobs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Blob/set . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1.1. create . . . . . . . . . . . . . . . . . . . . . . . 3
3.1.2. update . . . . . . . . . . . . . . . . . . . . . . . 4
3.1.3. destroy . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Blob/get . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Blob/lookup . . . . . . . . . . . . . . . . . . . . . . . 6
4. Security considerations . . . . . . . . . . . . . . . . . . . 7
5. IANA considerations . . . . . . . . . . . . . . . . . . . . . 8
5.1. JMAP Capability registration for "blob" . . . . . . . . . 8
5.2. JMAP Error Codes Registration for "unknownDataType" . . . 8
5.3. Creation of "JMAP Datatypes" Registry . . . . . . . . . . 8
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
7. Normative References . . . . . . . . . . . . . . . . . . . . 9
8. Informative References . . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
Sometimes JMAP ([RFC8620]) interactions require creating a Blob and
then referencing it. In the same way that IMAP Literals ([RFC7888])
were extended to reduce roundtrips for simple data, embedding simple
small blobs into the JMAP method stream can reduce roundtrips.
Likewise, when fetching an object, it can be useful to also fetch the
raw content of that object without a separate roundtrip.
Where JMAP is being proxied through a system which applies additional
access restrictions, it can be useful to be able to see where a blob
is referenced in order to decide whether to allow it to be
downloaded.
2. Conventions Used In This Document
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 BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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3. Blobs
A blob is a sequence of zero or more octets.
The JMAP base spec [RFC8210] defines the "Blob/copy" method, which is
unchanged by this specfication.
3.1. Blob/set
This is a standard JMAP "set" method.
3.1.1. create
*Properties:*
Any one of:
* data:asText: String|null
* data:asBase64: String|null
* data:asHex: String|null
* catenate: [SetObject] _list of octet sources in order_
Also:
* type: String|null
Result is:
* id: Id the blobId
* type: String|null _as given in the creation (if any); or detected
from content; or null_
* size: UnsignedInt _as per RFC8620 - the size of the file in
Octets_
Any other properties identical to those that would be returned in the
JSON response of the RFC8620 upload endpoint.
SetObject:
Any one of
* data:asText: String|null
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* data:asBase64: String|null
* data:asHex: String|null
OR a blobId source:
* blobId: Id
* offset: UnsignedInt|null
* length: UnsignedInt|null
3.1.2. update
It is not possible to update a Blob, so any update will result in a
"notUpdated" response.
3.1.3. destroy
If an uploaded Blob is not referenced by any persistent object, the
server SHOULD destroy the object. Some systems use a content-based
ID for blobs, so the server MAY respond "destroyed" and yet that
blobId still exist with the same content.
Example:
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Method Call:
[ "Blob/set", {
"accountId" : "account1",
"create" : {
"1": {
"data:asBase64": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKA
AAAA1BMVEX/AAAZ4gk3AAAAAXRSTlN/gFy0ywAAAApJRE
FUeJxjYgAAAAYAAzY3fKgAAAAASUVORK5CYII=",
"type" : "image/png"
},
},
}, "R1" ]
Response:
[ "Blob/set", {
"accountId" : "account1",
"created" : {
"1": {
"id" : "G4c6751edf9dd6903ff54b792e432fba781271beb",
"type" : "image/png",
"size" : 95
},
},
}, "R1" ]
3.2. Blob/get
A standard JMAP get.
*Properties:*
Any of
* data:asText
* data:asBase64
* data:asHex
* data _selects data:asText if the content is UTF-8, or
data:asBase64_
* size
If not given, returns "data" and "size".
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QUESTION: do we want to add range operators?
* offset: UnsignedInt|null
* length: UnsignedInt|null
Returns that range of octets (not characters!) from the blob.
Alternative possible syntax - ranges within the properties, e.g:
"data:asText:0:3000"
3.3. Blob/lookup
Given a list of blobIds, this method does a reverse lookup in each of
the provided datatypes to find the list of Ids within that datatype
which reference the provided blob.
The definition of reference is somewhat loosely defined, but roughly
means "you could discover this blobId by looking inside this object",
for example if a Mailbox contains an Email which references the
blobId, then it references that blobId. Likewise for a Thread.
*Parameters*
* accountId: "Id"
The id of the account used for the call.
* datatypes: [String]
A list of datatype names from the "JMAP Datatypes" registry for which
"Can Reference Blobs" is "Yes". The capability which defines each
type must also be requested.
If a datatype is not known by the server or the associated capability
has not been included then the server returns an "unknownDataType"
error.
* ids: [Id]
A list of blobId values to be looked for.
*Response*
* list: [BlobInfo]
A list of BlobInfo objects.
*BlobInfo Object*
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* id: Id
The Blob Identifier.
* datatypes: DataType[Id List]
A map from datatype to list of Ids of that datatype (e.g. the
datatype "Email" maps to a list of emailIds)
e.g.
[ "Blob/lookup", {
"datatypes": ["Mailbox", "Thread", "Email"],
"ids": ["Gd2f81008cf07d2425418f7f02a3ca63a8bc82003",
"G6f954bcb620f7f50fc8f21426bde3669da3d9067"]
}, "R1" ]
Response:
[ "Blob/lookup", {
"list": [
{
"id": "Gd2f81008cf07d2425418f7f02a3ca63a8bc82003",
"datatypes": {
"Mailbox": ["M54e97373", Mcbe6b662"],
"Thread": ["T1530616e"],
"Email": ["E16e70a73eb4", "E84b0930cf16"]
}
}
],
"notFound": ["G6f954bcb620f7f50fc8f21426bde3669da3d9067"]
}, "R1"]
4. Security considerations
TO BE IMPROVED:
JSON parsers are not all consistent in handling non-UTF-8 data. JMAP
requires that all JSON data be UTF-8 encoded, so servers MUST either
return "data:asBase64" or "isEncodingProblem: true" and modify the
data to be UTF-8 safe.
Servers MUST apply any access controls such that if the authenticated
user would be unable to discover the blobId by making queries, then
this fact can't be discovered via a Blob/lookup. For example, if an
Email exists in a Mailbox which the authenticated user does not have
access to see, then that emailId MUST not be returned in a lookup for
a blob which is referenced by that email.
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If a blob is not visible to a user at all, then the server SHOULD
return that blobId in the notFound array, however it may also return
an empty list for each datatype, as it may not be able to know if
other datatypes do reference that blob.
5. IANA considerations
5.1. JMAP Capability registration for "blob"
IANA is requested to register the "blob" JMAP Capability as follows:
Capability Name: urn:ietf:params:jmap:blob
Specification document: this document
Intended use: common
Change Controller: IETF
Security and privacy considerations: this document, Section XXX
5.2. JMAP Error Codes Registration for "unknownDataType"
IANA is requested to register the "unknownDataType" JMAP Error Code
as follows:
JMAP Error Code: unknownDataType
Intended use: common
Change Controller: IETF
Reference: this document
Description: The server does not recognise this data type, or the
capability to enable it was not present.
5.3. Creation of "JMAP Datatypes" Registry
IANA is requested to create a new registry "JMAP Datatypes" with the
initial content:
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+================+=========+======+=====================================+=========+
|Datatype name |Can |Can |Capability |Reference|
| |Reference|use | | |
| |Blobs |for | | |
| | |State | | |
| | |Change| | |
+================+=========+======+=====================================+=========+
|Core |No |No |urn:ietf:params:jmap:core |[RFC8620]|
+----------------+---------+------+-------------------------------------+---------+
|PushSubscription|No |No |urn:ietf:params:jmap:core |[RFC8620]|
+----------------+---------+------+-------------------------------------+---------+
|Mailbox |Yes |Yes |urn:ietf:params:jmap:mail |[RFC8621]|
+----------------+---------+------+-------------------------------------+---------+
|Thread |Yes |Yes |urn:ietf:params:jmap:mail |[RFC8621]|
+----------------+---------+------+-------------------------------------+---------+
|Email |Yes |Yes |urn:ietf:params:jmap:mail |[RFC8621]|
+----------------+---------+------+-------------------------------------+---------+
|EmailDelivery |No |Yes |urn:ietf:params:jmap:mail |[RFC8621]|
+----------------+---------+------+-------------------------------------+---------+
|SearchSnippet |No |No |urn:ietf:params:jmap:mail |[RFC8621]|
+----------------+---------+------+-------------------------------------+---------+
|Identity |No |Yes |urn:ietf:params:jmap:submission |[RFC8621]|
+----------------+---------+------+-------------------------------------+---------+
|EmailSubmission |No |Yes |urn:ietf:params:jmap:submission |[RFC8621]|
+----------------+---------+------+-------------------------------------+---------+
|VacationResponse|No |Yes |urn:ietf:params:jmap:vacationresponse|[RFC8621]|
+----------------+---------+------+-------------------------------------+---------+
|MDN |No |No |urn:ietf:params:jmap:mdn |[RFC9007]|
+----------------+---------+------+-------------------------------------+---------+
Table 1
6. Acknowledgements
TBD
7. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
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[RFC8210] Bush, R. and R. Austein, "The Resource Public Key
Infrastructure (RPKI) to Router Protocol, Version 1",
RFC 8210, DOI 10.17487/RFC8210, September 2017,
<https://www.rfc-editor.org/info/rfc8210>.
8. Informative References
[RFC7888] Melnikov, A., Ed., "IMAP4 Non-synchronizing Literals",
RFC 7888, DOI 10.17487/RFC7888, May 2016,
<https://www.rfc-editor.org/info/rfc7888>.
[RFC8620] Jenkins, N. and C. Newman, "The JSON Meta Application
Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July
2019, <https://www.rfc-editor.org/info/rfc8620>.
[RFC8621] Jenkins, N. and C. Newman, "The JSON Meta Application
Protocol (JMAP) for Mail", RFC 8621, DOI 10.17487/RFC8621,
August 2019, <https://www.rfc-editor.org/info/rfc8621>.
Author's Address
Bron Gondwana (editor)
Fastmail
Level 2, 114 William St
Melbourne VIC 3000
Australia
Email: brong@fastmailteam.com
URI: https://www.fastmail.com
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