Independent Submission K. Murchison Internet-Draft FastMail Intended status: Standards Track August 3, 2018 Expires: February 4, 2019 A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket draft-murchison-jmap-websocket-01 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 Should we allow push notifications over the WS connection? o Should we allow out of order processing od requests? 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 February 4, 2019. 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 Murchison Expires February 4, 2019 [Page 1]
Internet-Draft JMAP Over WebSocket August 2018 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 . . . . . . . . . . . . . . 3 3. Discovering Support for JMAP over WebSocket . . . . . . . . . 3 4. JMAP Subprotocol . . . . . . . . . . . . . . . . . . . . . . 3 4.1. Handshake . . . . . . . . . . . . . . . . . . . . . . . . 3 4.2. WebSocket Messages . . . . . . . . . . . . . . . . . . . 4 4.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 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 Appendix A. Change History (To be removed by RFC Editor before publication) . . . . . . . . . . . . . . . . . . . . 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. Furthermore, the WebSocket binding for JMAP can optionally compress [RFC7692] JMAP API requests. Although compression of HTTP responses is ubiquitous, compression of HTTP requests has very low, if any deployment, and therefore isn't an option for JMAP API requests over HTTP. Murchison Expires February 4, 2019 [Page 2]
Internet-Draft JMAP Over WebSocket August 2018 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 capabilities object is returned as part of the standard JMAP Session object (see Section 2 of [I-D.ietf-jmap-core]). Servers supporting this specification MUST add a property called "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: wsUrl: "String" The URL to use for JMAP over WebSocket. 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 and responses through a WebSocket connection. Binary data MUST NOT be uploaded or downloaded through a WebSocket JMAP connection. 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 [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 'wsURL' (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. Murchison Expires February 4, 2019 [Page 3]
Internet-Draft JMAP Over WebSocket August 2018 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. 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 [I-D.ietf-jmap-core]) when sent from the client to the server, and in the form of a single JMAP Response object or JSON Problem Details object (see Sections 3.4 and 3.6.1 respectively of [I-D.ietf-jmap-core]) when sent from the server to the client. 4.3. 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 'wsURL' has been advertised in the JMAP Session object as '/jmap/'. Note that folding of header fields is for editorial purposes only. Murchison Expires February 4, 2019 [Page 4]
Internet-Draft JMAP Over WebSocket August 2018 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: Basic 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": [ ... ] } Murchison Expires February 4, 2019 [Page 5]
Internet-Draft JMAP Over WebSocket August 2018 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 = Basic 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": [ ... ] } 5. Security Considerations TODO Murchison Expires February 4, 2019 [Page 6]
Internet-Draft JMAP Over WebSocket August 2018 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-07 (work in progress), June 2018. [I-D.ietf-jmap-core] Jenkins, N., "JSON Meta Application Protocol", draft-ietf- jmap-core-06 (work in progress), July 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>. [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>. Murchison Expires February 4, 2019 [Page 7]
Internet-Draft JMAP Over WebSocket August 2018 [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-06 (work in progress), July 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 Appendix A. Change History (To be removed by RFC Editor before publication) Changes since -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 Kenneth Murchison FastMail US LLC 1315 Walnut Street - Suite 320 Philadelphia, PA 19107 USA Email: murch@fastmailteam.com Murchison Expires February 4, 2019 [Page 8]