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 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 working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." 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. Gondwana Expires 20 May 2021 [Page 1] Internet-Draft JMAP Blob November 2020 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 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 . . . . . . . . . . . . . . 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. Gondwana Expires 20 May 2021 [Page 2] Internet-Draft JMAP Blob November 2020 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_ Gondwana Expires 20 May 2021 [Page 3] Internet-Draft JMAP Blob November 2020 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: Gondwana Expires 20 May 2021 [Page 4] Internet-Draft JMAP Blob November 2020 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". Gondwana Expires 20 May 2021 [Page 5] Internet-Draft JMAP Blob November 2020 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: Gondwana Expires 20 May 2021 [Page 6] Internet-Draft JMAP Blob November 2020 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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [RFC8620] Jenkins, N. and C. Newman, "The JSON Meta Application Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July 2019, . 8. Informative References [RFC7888] Melnikov, A., Ed., "IMAP4 Non-synchronizing Literals", RFC 7888, DOI 10.17487/RFC7888, May 2016, . Author's Address Bron Gondwana (editor) Fastmail Level 2, 114 William St Melbourne VIC 3000 Australia Email: brong@fastmailteam.com Gondwana Expires 20 May 2021 [Page 7] Internet-Draft JMAP Blob November 2020 URI: https://www.fastmail.com Gondwana Expires 20 May 2021 [Page 8]