A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket
draft-ietf-jmap-websocket-03
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 8887.
|
|
|---|---|---|---|
| Author | Ken Murchison | ||
| Last updated | 2019-11-16 (Latest revision 2019-07-23) | ||
| Replaces | draft-murchison-jmap-websocket | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews |
TSVART IETF Last Call review
(of
-04)
by Bob Briscoe
Ready w/issues
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Consensus: Waiting for Write-Up | |
| Document shepherd | Jim Fenton | ||
| IESG | IESG state | Became RFC 8887 (Proposed Standard) | |
| Consensus boilerplate | Yes | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | Jim Fenton <fenton@bluepopcorn.net> |
draft-ietf-jmap-websocket-03
JMAP K. Murchison
Internet-Draft Fastmail
Intended status: Standards Track July 22, 2019
Expires: January 23, 2020
A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket
draft-ietf-jmap-websocket-03
Abstract
This document defines a binding for the JSON Meta Application
Protocol (JMAP) over a WebSocket transport layer. The WebSocket
binding for JMAP provides higher performance than the current HTTP
binding for JMAP.
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 January 23, 2020.
Copyright Notice
Copyright (c) 2019 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 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.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. Discovering Support for JMAP over WebSocket . . . . . . . . . 3
4. JMAP Subprotocol . . . . . . . . . . . . . . . . . . . . . . 3
4.1. Handshake . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. WebSocket Messages . . . . . . . . . . . . . . . . . . . 4
4.2.1. JMAP Requests . . . . . . . . . . . . . . . . . . . . 4
4.2.2. JMAP Responses . . . . . . . . . . . . . . . . . . . 5
4.2.3. JMAP Request-level Errors . . . . . . . . . . . . . . 5
4.2.4. JMAP Push Notifications . . . . . . . . . . . . . . . 5
4.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6.1. Registration of the WebSocket JMAP Subprotocol . . . . . 11
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . 12
8.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Appendix A. Change History (To be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 12
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
JMAP [RFC8620] over HTTP [RFC7235] requires that every JMAP API
request be authenticated. Depending on the type of authentication
used by the JMAP client and the configuration of the JMAP server,
authentication could be an expensive operation both in time and
resources. In such circumstances, authenticating every JMAP API
request may harm performance.
The WebSocket [RFC6455] binding for JMAP eliminates this performance
hit by authenticating just the WebSocket handshake request and having
those credentials remain in effect for the duration of the WebSocket
connection. This binding supports JMAP API requests and responses,
with optional support for push notifications.
Furthermore, the WebSocket binding for JMAP can optionally compress
[RFC7692] both JMAP API requests and responses. Although compression
of HTTP responses is ubiquitous, compression of HTTP requests has
very low, if any deployment, and therefore isn't a viable option for
JMAP API requests over HTTP.
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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 [1] [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The same terminology is used in this document as in the core JMAP
specification.
3. Discovering Support for JMAP over WebSocket
The JMAP capabilities object is returned as part of the standard JMAP
Session object (see Section 2 of [RFC8620]). Servers supporting this
specification MUST add a property named
"urn:ietf:params:jmap:websocket" to the capabilities object. The
value of this property is an object which MUST contain the following
information on server capabilities:
o webSocketUrl: "String"
The URL to use for initiating a JMAP over WebSocket handshake.
o supportsWebSocketPush: "Boolean"
This is true if the server supports push notifications over the
WebSocket, as described in Section 4.2.4.
Example:
"urn:ietf:params:jmap:websocket": {
"webSocketUrl": "https://server.example.com/jmap/ws/",
"supportsWebSocketPush": true
}
4. JMAP Subprotocol
The term WebSocket subprotocol refers to an application-level
protocol layered on top of a WebSocket connection. This document
specifies the WebSocket JMAP subprotocol for carrying JMAP API
requests, responses, and optional push notifications through a
WebSocket connection. Binary data MUST NOT be uploaded or downloaded
through a WebSocket JMAP connection. Binary data is handled per
Section 6 of [RFC8620] via a separate HTTP connection or stream.
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4.1. Handshake
The JMAP WebSocket client and JMAP WebSocket server negotiate the use
of the WebSocket JMAP subprotocol during the WebSocket handshake,
either via a HTTP/1.1 Upgrade request (see Section 1.3 of [RFC6455])
or a HTTP/2 Extended CONNECT request (see Section 5 of [RFC8441]).
Regardless of the method used for the WebSocket handshake, the client
MUST make an authenticated [RFC7235] HTTP request on the JMAP
"webSocketUrl" (Section 3), and the client MUST include the value
"jmap" in the list of protocols for the "Sec-WebSocket-Protocol"
header field. The reply from the server MUST also contain "jmap" in
its corresponding "Sec-WebSocket-Protocol" header field in order for
a JMAP subprotocol connection to be established.
If a client receives a handshake response that does not include
"jmap" in the "Sec-WebSocket-Protocol" header, then a JMAP
subprotocol WebSocket connection was not established and the client
MUST close the WebSocket connection.
Once the handshake has successfully completed, the WebSocket
connection is established and can be used for JMAP API requests,
responses, and optional push notifications. Other message types MUST
NOT be transmitted over this connection.
The credentials used for authenticating the HTTP request to initiate
the handshake remain in effect for the duration of the WebSocket
connection.
4.2. WebSocket Messages
Data frame messages in the JMAP subprotocol MUST be of the text type
and contain UTF-8 encoded data. The messages MUST be in the form of
a single JMAP Request object (see Section 3.2 of [RFC8620]), JMAP
WebSocketPushEnable object (see Section 4.2.4.2), or JMAP
WebSocketPushDisable object (see Section 4.2.4.3) when sent from the
client to the server, and in the form of a single JMAP Response
object, JSON Problem Details object, or JMAP StateChange object (see
Sections 3.3, 3.5.1, and 7.1 respectively of [RFC8620]) when sent
from the server to the client.
4.2.1. JMAP Requests
This specification adds two extra arguments to the Request object:
o @type: "String"
This MUST be the string "Request".
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o id: "String" (optional)
A client-specified identifier for the request.
JMAP over WebSocket allows the server to process requests out of
order. The client-specified identifier is used as a mechanism for
the client to correlate requests and responses.
Additionally, the "maxConcurrentRequests" field in the "capabilities"
object (see Section 2 of [RFC8620]) limits the number of inflight
requests over the WebSocket.
4.2.2. JMAP Responses
This specification adds two extra arguments to the Response object:
o @type: "String"
This MUST be the string "Response".
o requestId: "String" (optional; only returned if given in the
request)
The client-specified identifier in the corresponding request.
4.2.3. JMAP Request-level Errors
This specification adds two extra arguments to the Problem Details
object:
o @type: "String"
This MUST be the string "RequestError".
o requestId: "String" (optional; only returned if given in the
request)
The client-specified identifier in the corresponding request.
4.2.4. JMAP Push Notifications
JMAP over WebSocket servers that support push notifications on the
WebSocket will advertise a "supportsWebSocketPush" property with a
value of true in the server capabilities object.
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4.2.4.1. Notification Format
All push notifications take the form of a standard StateChange object
(see Section 7.1 of [RFC8620]).
This specification adds one extra argument to the StateChange object:
o pushState: "String" (optional)
A (preferably short) string representing the state on the server
for ALL of the data types in the account (not just the objects
returned in this call).
4.2.4.2. Enabling Notifications
A client enables push notifications from the server by sending a
WebSocketPushEnable object to the server. A WebSocketPushEnable
object has the following properties:
o @type: "String" This MUST be the string "WebSocketPushEnable".
o dataTypes: "String[]|null"
A list of data type names (e.g. "Mailbox", "Email") that the
client is interested in. A StateChange notification will only be
sent if the data for one of these types changes. Other types are
omitted from the TypeState object. If null, changes will be
pushed for all supported data types.
o pushState: "String" (optional)
The last "pushState" token that the client received from the
server. Upon receipt of a "pushState" token, the server SHOULD
immediately send all changes since that state token.
4.2.4.3. Disabling Notifications
A client disables push notifications from the server by sending a
WebSocketPushDisable object to the server. A WebSocketPushDisable
object has the following property:
o @type: "String"
This MUST be the string "WebSocketPushDisable".
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4.3. Examples
The following examples show WebSocket JMAP opening handshakes, a JMAP
Core/echo request and response, and a subsequent closing handshake.
The examples assume that the JMAP "webSocketUrl" has been advertised
in the JMAP Session object as "/jmap/ws/". Note that folding of
header fields is for editorial purposes only.
WebSocket JMAP connection via HTTP/1.1 with push notifications for
mail [I-D.ietf-jmap-mail] enabled:
[[ From Client ]] [[ From Server ]]
GET /jmap/ws/ HTTP/1.1
Host: server.example.com
Upgrade: websocket
Connection: Upgrade
Authorization: Basic Zm9vOmJhcg==
Sec-WebSocket-Key:
dGhlIHNhbXBsZSBub25jZQ==
Sec-WebSocket-Protocol: jmap
Sec-WebSocket-Version: 13
Origin: http://www.example.com
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept:
s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
Sec-WebSocket-Protocol: jmap
[WebSocket connection established]
WS_DATA
{
"@type": "WebSocketPushEnable",
"dataTypes": [ "Mailbox", "Email" ],
"pushState": "aaa"
}
WS_DATA
{
"@type": "StateChange",
"changed": {
"a456": {
"Email": "d35ecb040aab"
}
},
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"pushState": "bbb"
}
WS_DATA
{
"@type": "Request",
"id": "R1",
"using": [ "urn:ietf:params:jmap:core" ],
"methodCalls": [
[
"Core/echo", {
"hello": true,
"high": 5
},
"b3ff"
]
]
}
WS_DATA
{
"@type": "Response",
"requestId": "R1",
"methodResponses": [
[
"Core/echo", {
"hello": true,
"high": 5
},
"b3ff"
]
]
}
WS_DATA
The quick brown fox jumps
over the lazy dog.
WS_DATA
{
"@type": "RequestError",
"requestId": null,
"type":
"urn:ietf:params:jmap:error:notJSON",
"status": 400,
"detail":
"The request did not parse as I-JSON."
}
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WS_DATA
{
"@type": "StateChange",
"changed": {
"a123": {
"Mailbox": "0af7a512ce70"
}
}
"pushState": "ccc"
}
WS_CLOSE
WS_CLOSE
[WebSocket connection closed]
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WebSocket JMAP connection on a HTTP/2 stream which also negotiates
compression [RFC7692]:
[[ From Client ]] [[ From Server ]]
SETTINGS
SETTINGS_ENABLE_CONNECT_PROTOCOL = 1
HEADERS + END_HEADERS
:method = CONNECT
:protocol = websocket
:scheme = https
:path = /jmap/ws/
:authority = server.example.com
authorization = Basic Zm9vOmJhcg==
sec-websocket-protocol = jmap
sec-websocket-version = 13
sec-websocket-extensions =
permessage-deflate
origin = http://www.example.com
HEADERS + END_HEADERS
:status = 200
sec-websocket-protocol = jmap
sec-websocket-extensions =
permessage-deflate
[WebSocket connection established]
DATA
WS_DATA
[compressed text]
DATA
WS_DATA
[compressed text]
...
DATA + END_STREAM
WS_CLOSE
DATA + END_STREAM
WS_CLOSE
[WebSocket connection closed]
[HTTP/2 stream closed]
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5. Security Considerations
The security considerations for both WebSocket (see Section 10 of
[RFC6455]) and JMAP (see Section 8 of [RFC8620]) apply to the
WebSocket JMAP subprotocol.
6. IANA Considerations
6.1. Registration of the WebSocket JMAP Subprotocol
This specification requests IANA to register the WebSocket JMAP
subprotocol under the "WebSocket Subprotocol Name" Registry with the
following data:
Subprotocol Identifier: jmap
Subprotocol Common Name: WebSocket Transport for JMAP (JSON Meta
Application Protocol)
Subprotocol Definition: RFCXXXX (this document)
7. Acknowledgments
The author would like to thank the following individuals for
contributing their ideas and support for writing this specification:
Neil Jenkins, Robert Mueller, and Chris Newman.
8. References
8.1. 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>.
[RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol",
RFC 6455, DOI 10.17487/RFC6455, December 2011,
<https://www.rfc-editor.org/info/rfc6455>.
[RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Authentication", RFC 7235,
DOI 10.17487/RFC7235, June 2014,
<https://www.rfc-editor.org/info/rfc7235>.
[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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[RFC8441] McManus, P., "Bootstrapping WebSockets with HTTP/2",
RFC 8441, DOI 10.17487/RFC8441, September 2018,
<https://www.rfc-editor.org/info/rfc8441>.
[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>.
8.2. Informative References
[I-D.ietf-jmap-mail]
Jenkins, N. and C. Newman, "JMAP (JSON Meta Application
Protocol) for Mail", draft-ietf-jmap-mail-16 (work in
progress), March 2019.
[RFC7692] Yoshino, T., "Compression Extensions for WebSocket",
RFC 7692, DOI 10.17487/RFC7692, December 2015,
<https://www.rfc-editor.org/info/rfc7692>.
8.3. URIs
[1] https://tools.ietf.org/html/bcp14
Appendix A. Change History (To be removed by RFC Editor before
publication)
Changes since ietf-02:
o Updated JMAP Core reference to RFC 8620.
o Added 'WebSocketPushDisable' object.
o Editorial and formatting changes.
Changes since ietf-01:
o Changed 'wsURL' to 'webSocketUrl' and removed push query option.
o Added 'supportsWebSocketPush' capability.
o Added '@type' argument to Request object.
o Added 'WebSocketPushEnable' object.
o Added 'pushState' argument to StateChange object.
o Updated example.
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o Minor Editorial changes.
Changes since ietf-00:
o Added text describing advertisement of and selection of optional
push notifications.
o Minor Editorial changes.
Changes since murchison-02:
o Renamed as a JMAP WG document.
o Allow out of order processing.
o Allow push notifications.
o Modified examples.
o Add Security Considerations text.
o Minor Editorial changes.
Changes since murchison-01:
o Updated WebSocket over HTTP/2 reference to RFC8144.
Changes since murchison-00:
o Fleshed out section on discovery of support for JMAP over
WebSocket.
o Allow JSON Problem Details objects to be returned by the server
for toplevel errors.
o Mentioned the ability to compress JMAP API requests.
o Minor Editorial changes.
Author's Address
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Kenneth Murchison
Fastmail US LLC
1429 Walnut Street - Suite 1201
Philadelphia, PA 19102
USA
Email: murch@fastmailteam.com
URI: http://www.fastmail.com/
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