Internet DRAFT - draft-gondwana-jmap-blob
draft-gondwana-jmap-blob
JMAP B. Gondwana, Ed.
Internet-Draft Fastmail
Updates: 8620 (if approved) 16 November 2020
Intended status: Standards Track
Expires: 20 May 2021
JMAP Blob management extension
draft-gondwana-jmap-blob-01
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 handle Blobs, by making inline
method calls within a standard JMAP request.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 20 May 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used In This Document . . . . . . . . . . . . . . 3
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 . . . . . . . . . . . . . . . . . . . 6
5. IANA considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
7. Normative References . . . . . . . . . . . . . . . . . . . . 7
8. Informative References . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
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 is providing
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.
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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.
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 byte 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_
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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
* 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 bytes (not characters!) from the blob
3.3. Blob/lookup
A reverse lookup!
Work to be done here, but something like this.
Map from blobId to object type:
e.g.
[ "Blob/lookup", {
"objects": ["Mailbox", "Thread", "Email"],
"ids": ["Gd2f81008cf07d2425418f7f02a3ca63a8bc82003",
"G6f954bcb620f7f50fc8f21426bde3669da3d9067"]
}, "R1" ]
Response:
[ "Blob/lookup", {
"list": [
{
"id": "Gd2f81008cf07d2425418f7f02a3ca63a8bc82003",
"Mailbox": ["M54e97373", Mcbe6b662"],
"Thread": ["T1530616e"],
"Email": ["E16e70a73eb4", "E84b0930cf16"]
},
],
"notFound": ["G6f954bcb620f7f50fc8f21426bde3669da3d9067"]
}, "R1"]
This tells which objects of each type "contain" a reference to that
blobId. "Contain" is defined somewhat losely here, so for example
"the Mailbox contains an Email which references this blobId" is the
standard in the response above, likewise for Thread.
4. Security considerations
TO BE IMPROVED:
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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.
5. IANA considerations
TBD
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>.
[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>.
[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>.
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>.
Author's Address
Bron Gondwana (editor)
Fastmail
Level 2, 114 William St
Melbourne VIC 3000
Australia
Email: brong@fastmailteam.com
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URI: https://www.fastmail.com
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