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Versions: 00

Independent Submission                                      K. Murchison
Internet-Draft                                                  FastMail
Intended status: Standards Track                            May 29, 2018
Expires: November 30, 2018


   A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket
                   draft-murchison-jmap-websocket-00

Abstract

   This document defines a binding for the JSON Meta Application
   Protocol (JMAP) over a WebSocket transport layer.  A WebSocket
   binding for JMAP provides higher performance than the current HTTP
   binding for JMAP.

Open Issues

   o  Discovering support for JMAP over WebSocket.

   o  Should we allow push notifications over the WS connection?

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 November 30, 2018.

Copyright Notice

   Copyright (c) 2018 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



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   carefully, as they describe your rights and restrictions with respect
   to this document.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   2
   3.  JMAP Subprotocol  . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Handshake . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  WebSocket Messages  . . . . . . . . . . . . . . . . . . .   3
     3.3.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Discovering Support for JMAP over WebSocket . . . . . . . . .   6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Registration of the WebSocket JMAP Sub-Protocol . . . . .   7
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   8
     8.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   JMAP over HTTP 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 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.

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.








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3.  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 and responses through a WebSocket connection.  Binary data
   MUST NOT be uploaded or downloaded through a WebSocket JMAP
   connection.

3.1.  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
   [I-D.ietf-httpbis-h2-websockets]).

   Regardless of the method used for the WebSocket handshake, the client
   MUST make an authenticated [RFC7235] HTTP request on the JMAP
   'apiURL' (see Section 2 of [I-D.ietf-jmap-core]), 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 and
   responses.  Messages other than JMAP API requests and responses 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.

3.2.  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
   [I-D.ietf-jmap-core]) when sent from the client to the server, and in
   the form of a single JMAP Response object (see Section 3.4 of
   [I-D.ietf-jmap-core]) when sent from the server to the client.



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3.3.  Examples

   The following examples show WebSocket JMAP handshakes and a
   subsequent JMAP for Mail [I-D.ietf-jmap-mail] request and response.
   The examples assume that the JMAP 'apiURL' has been advertised in the
   JMAP Session object as '/jmap/'.  Note that folding of header fields
   is for editorial purposes only.












































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   WebSocket JMAP handshake via HTTP/1.1 which also negotiates
   compression [RFC7692]:

   [[ From Client ]]                  [[ From Server ]]

   GET /jmap/ HTTP/1.1
   Host: server.example.com
   Upgrade: websocket
   Connection: Upgrade
   Authorization: Zm9vOmJhcg==
   Sec-WebSocket-Key:
     dGhlIHNhbXBsZSBub25jZQ==
   Sec-WebSocket-Protocol: jmap
   Sec-WebSocket-Version: 13
   Sec-Websocket-Extensions:
     permessage-deflate
   Origin: http://www.example.com

                                      HTTP/1.1 101 Switching Protocols
                                      Upgrade: websocket
                                      Connection: Upgrade
                                      Sec-WebSocket-Accept:
                                        s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
                                      Sec-WebSocket-Protocol: jmap
                                      Sec-Websocket-Extensions:
                                        permessage-deflate

   [WebSocket connection established]

   {
     "using": [ "urn:ietf:params:jmap:core",
                "urn:ietf:params:jmap:mail" ],
     "methodCalls": [
       ...
     ]
   }

                                      {
                                        "methodResponses": [
                                          ...
                                        ]
                                      }









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   WebSocket JMAP handshake on a HTTP/2 stream:

 [[ From Client ]]                  [[ From Server ]]

                                    SETTINGS
                                    SETTINGS_ENABLE_CONNECT_PROTOCOL = 1

 HEADERS + END_HEADERS
 :method = CONNECT
 :protocol = websocket
 :scheme = https
 :path = /jmap/
 :authority = server.example.com
 authorization = Zm9vOmJhcg==
 sec-websocket-protocol = jmap
 sec-websocket-version = 13
 origin = http://www.example.com

                                    HEADERS + END_HEADERS
                                    :status = 200
                                    sec-websocket-protocol = jmap

 [WebSocket connection established]

 DATA
 {
   "using": [ "urn:ietf:params:jmap:core",
              "urn:ietf:params:jmap:mail" ],
   "methodCalls": [
     ...
   ]
 }

                                    DATA
                                    {
                                      "methodResponses": [
                                        ...
                                      ]
                                    }

4.  Discovering Support for JMAP over WebSocket

   TODO

   o  Do we define a new capability for the Session resource?

   o  Do we simply return an Upgrade:websocket header field in HTTP/1.1
      responses to API requests?



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   o  How would we advertise via HTTP/2 protocol as Alt-Svc is per
      origin, NOT per-source?

5.  Security Considerations

   TODO

6.  Privacy Considerations

   TODO

7.  IANA Considerations

7.1.  Registration of the WebSocket JMAP Sub-Protocol

   This specification requests IANA to register the WebSocket JMAP sub-
   protocol 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)

8.  References

8.1.  Normative References

   [I-D.ietf-httpbis-h2-websockets]
              McManus, P., "Bootstrapping WebSockets with HTTP/2",
              draft-ietf-httpbis-h2-websockets-05 (work in progress),
              May 2018.

   [I-D.ietf-jmap-core]
              Jenkins, N., "JSON Meta Application Protocol", draft-ietf-
              jmap-core-05 (work in progress), May 2018.

   [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>.




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   [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>.

8.2.  Informative References

   [I-D.ietf-jmap-mail]
              Jenkins, N., "JMAP for Mail", draft-ietf-jmap-mail-05
              (work in progress), May 2018.

   [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

Author's Address

   Kenneth Murchison
   FastMail US LLC

   Email: murch@fastmailteam.com






















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