Difference between revisions of "RFC8887"

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Internet Engineering Task Force (IETF)                      K. Murchison
 
Internet Engineering Task Force (IETF)                      K. Murchison
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ISSN: 2070-1721
 
ISSN: 2070-1721
  
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+
A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket
−
  A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket
 
  
 
Abstract
 
Abstract
  
−
  This document defines a binding for the JSON Meta Application
+
This document defines a binding for the JSON Meta Application
−
  Protocol (JMAP) over a WebSocket transport layer.  The WebSocket
+
Protocol (JMAP) over a WebSocket transport layer.  The WebSocket
−
  binding for JMAP provides higher performance than the current HTTP
+
binding for JMAP provides higher performance than the current HTTP
−
  binding for JMAP.
+
binding for JMAP.
  
 
Status of This Memo
 
Status of This Memo
  
−
  This is an Internet Standards Track document.
+
This is an Internet Standards Track document.
  
−
  This document is a product of the Internet Engineering Task Force
+
This document is a product of the Internet Engineering Task Force
−
  (IETF).  It represents the consensus of the IETF community.  It has
+
(IETF).  It represents the consensus of the IETF community.  It has
−
  received public review and has been approved for publication by the
+
received public review and has been approved for publication by the
−
  Internet Engineering Steering Group (IESG).  Further information on
+
Internet Engineering Steering Group (IESG).  Further information on
−
  Internet Standards is available in Section 2 of RFC 7841.
+
Internet Standards is available in Section 2 of RFC 7841.
  
−
  Information about the current status of this document, any errata,
+
Information about the current status of this document, any errata,
−
  and how to provide feedback on it may be obtained at
+
and how to provide feedback on it may be obtained at
−
  https://www.rfc-editor.org/info/rfc8887.
+
https://www.rfc-editor.org/info/rfc8887.
  
 
Copyright Notice
 
Copyright Notice
  
−
  Copyright (c) 2020 IETF Trust and the persons identified as the
+
Copyright (c) 2020 IETF Trust and the persons identified as the
−
  document authors.  All rights reserved.
+
document authors.  All rights reserved.
  
−
  This document is subject to BCP 78 and the IETF Trust's Legal
+
This document is subject to BCP 78 and the IETF Trust's Legal
−
  Provisions Relating to IETF Documents
+
Provisions Relating to IETF Documents
−
  (https://trustee.ietf.org/license-info) in effect on the date of
+
(https://trustee.ietf.org/license-info) in effect on the date of
−
  publication of this document.  Please review these documents
+
publication of this document.  Please review these documents
−
  carefully, as they describe your rights and restrictions with respect
+
carefully, as they describe your rights and restrictions with respect
−
  to this document.  Code Components extracted from this document must
+
to this document.  Code Components extracted from this document must
−
  include Simplified BSD License text as described in Section 4.e of
+
include Simplified BSD License text as described in Section 4.e of
−
  the Trust Legal Provisions and are provided without warranty as
+
the Trust Legal Provisions and are provided without warranty as
−
  described in the Simplified BSD License.
+
described in the Simplified BSD License.
  
 
Table of Contents
 
Table of Contents
  
−
  1.  Introduction
+
1.  Introduction
−
  2.  Conventions Used in This Document
+
2.  Conventions Used in This Document
−
  3.  Discovering Support for JMAP over WebSocket
+
3.  Discovering Support for JMAP over WebSocket
−
  4.  JMAP Subprotocol
+
4.  JMAP Subprotocol
−
    4.1.  Authentication
+
  4.1.  Authentication
−
    4.2.  Handshake
+
  4.2.  Handshake
−
    4.3.  WebSocket Messages
+
  4.3.  WebSocket Messages
−
      4.3.1.  Handling Invalid Data
+
    4.3.1.  Handling Invalid Data
−
      4.3.2.  JMAP Requests
+
    4.3.2.  JMAP Requests
−
      4.3.3.  JMAP Responses
+
    4.3.3.  JMAP Responses
−
      4.3.4.  JMAP Request-Level Errors
+
    4.3.4.  JMAP Request-Level Errors
−
      4.3.5.  JMAP Push Notifications
+
    4.3.5.  JMAP Push Notifications
−
    4.4.  Examples
+
  4.4.  Examples
−
  5.  Security Considerations
+
5.  Security Considerations
−
    5.1.  Connection Confidentiality and Integrity
+
  5.1.  Connection Confidentiality and Integrity
−
    5.2.  Non-browser Clients
+
  5.2.  Non-browser Clients
−
  6.  IANA Considerations
+
6.  IANA Considerations
−
    6.1.  Registration of the WebSocket JMAP Subprotocol
+
  6.1.  Registration of the WebSocket JMAP Subprotocol
−
  7.  References
+
7.  References
−
    7.1.  Normative References
+
  7.1.  Normative References
−
    7.2.  Informative References
+
  7.2.  Informative References
−
  Acknowledgments
+
Acknowledgments
−
  Author's Address
+
Author's Address
  
−
1.  Introduction
+
== Introduction ==
  
−
  JMAP [RFC8620] over HTTP [RFC7235] requires that every JMAP API
+
JMAP [RFC8620] over HTTP [RFC7235] requires that every JMAP API
−
  request be authenticated.  Depending on the type of authentication
+
request be authenticated.  Depending on the type of authentication
−
  used by the JMAP client and the configuration of the JMAP server,
+
used by the JMAP client and the configuration of the JMAP server,
−
  authentication could be an expensive operation both in time and
+
authentication could be an expensive operation both in time and
−
  resources.  In such circumstances, reauthenticating for every JMAP
+
resources.  In such circumstances, reauthenticating for every JMAP
−
  API request may harm performance.
+
API request may harm performance.
  
−
  The WebSocket [RFC6455] binding for JMAP eliminates this performance
+
The WebSocket [RFC6455] binding for JMAP eliminates this performance
−
  hit by authenticating just the WebSocket handshake request and having
+
hit by authenticating just the WebSocket handshake request and having
−
  those credentials remain in effect for the duration of the WebSocket
+
those credentials remain in effect for the duration of the WebSocket
−
  connection.  This binding supports JMAP API requests and responses,
+
connection.  This binding supports JMAP API requests and responses,
−
  with optional support for push notifications.
+
with optional support for push notifications.
  
−
  Furthermore, the WebSocket binding for JMAP can optionally compress
+
Furthermore, the WebSocket binding for JMAP can optionally compress
−
  [RFC7692] both JMAP API requests and responses.  Although compression
+
[RFC7692] both JMAP API requests and responses.  Although compression
−
  of HTTP responses is ubiquitous, compression of HTTP requests has
+
of HTTP responses is ubiquitous, compression of HTTP requests has
−
  very low, if any, deployment and therefore isn't a viable option for
+
very low, if any, deployment and therefore isn't a viable option for
−
  JMAP API requests over HTTP.
+
JMAP API requests over HTTP.
  
−
2.  Conventions Used in This Document
+
== Conventions Used in This Document ==
  
−
  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
−
  "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
+
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
−
  "OPTIONAL" in this document are to be interpreted as described in
+
"OPTIONAL" in this document are to be interpreted as described in
−
  BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
+
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
−
  capitals, as shown here.
+
capitals, as shown here.
  
−
  This document uses the terminology defined in the core JMAP
+
This document uses the terminology defined in the core JMAP
−
  specification [RFC8620].
+
specification [RFC8620].
  
−
3.  Discovering Support for JMAP over WebSocket
+
== Discovering Support for JMAP over WebSocket ==
  
−
  The JMAP capabilities object is returned as part of the standard JMAP
+
The JMAP capabilities object is returned as part of the standard JMAP
−
  Session object (see Section 2 of [RFC8620]).  Servers supporting this
+
Session object (see Section 2 of [RFC8620]).  Servers supporting this
−
  specification MUST add a property named
+
specification MUST add a property named
−
  "urn:ietf:params:jmap:websocket" to the capabilities object.  The
+
"urn:ietf:params:jmap:websocket" to the capabilities object.  The
−
  value of this property is an object that MUST contain the following
+
value of this property is an object that MUST contain the following
−
  information on server capabilities:
+
information on server capabilities:
  
−
  *  url: "String"
+
*  url: "String"
  
−
      The wss-URI (see Section 3 of [RFC6455]) to use for initiating a
+
  The wss-URI (see Section 3 of [RFC6455]) to use for initiating a
−
      JMAP-over-WebSocket handshake (the "WebSocket URL endpoint"
+
  JMAP-over-WebSocket handshake (the "WebSocket URL endpoint"
−
      colloquially).
+
  colloquially).
  
−
  *  supportsPush: "Boolean"
+
*  supportsPush: "Boolean"
  
−
      This is true if the server supports push notifications over the
+
  This is true if the server supports push notifications over the
−
      WebSocket, as described in Section 4.3.5.
+
  WebSocket, as described in Section 4.3.5.
  
−
  Example:
+
Example:
  
−
  "urn:ietf:params:jmap:websocket": {
+
"urn:ietf:params:jmap:websocket": {
−
    "url": "wss://server.example.com/jmap/ws/",
+
  "url": "wss://server.example.com/jmap/ws/",
−
    "supportsPush": true
+
  "supportsPush": true
−
  }
+
}
  
−
4.  JMAP Subprotocol
+
== JMAP Subprotocol ==
  
−
  The term WebSocket subprotocol refers to an application-level
+
The term WebSocket subprotocol refers to an application-level
−
  protocol layered on top of a WebSocket connection.  This document
+
protocol layered on top of a WebSocket connection.  This document
−
  specifies the WebSocket JMAP subprotocol for carrying JMAP API
+
specifies the WebSocket JMAP subprotocol for carrying JMAP API
−
  requests, responses, and optional push notifications through a
+
requests, responses, and optional push notifications through a
−
  WebSocket connection.  Binary data is handled per Section 6 of
+
WebSocket connection.  Binary data is handled per Section 6 of
−
  [RFC8620] (via a separate HTTP connection or stream) or per a future
+
[RFC8620] (via a separate HTTP connection or stream) or per a future
−
  extension to JMAP or this specification.
+
extension to JMAP or this specification.
  
−
4.1.  Authentication
+
=== Authentication ===
  
−
  A JMAP WebSocket connection is authenticated by presenting a user's
+
A JMAP WebSocket connection is authenticated by presenting a user's
−
  credentials in the HTTP request [RFC7235] that initiates the
+
credentials in the HTTP request [RFC7235] that initiates the
−
  WebSocket handshake.  See Section 8.2 of [RFC8620] for
+
WebSocket handshake.  See Section 8.2 of [RFC8620] for
−
  recommendations regarding the selection of HTTP authentication
+
recommendations regarding the selection of HTTP authentication
−
  schemes.
+
schemes.
  
−
4.2.  Handshake
+
=== Handshake ===
  
−
  The JMAP WebSocket client and JMAP WebSocket server negotiate the use
+
The JMAP WebSocket client and JMAP WebSocket server negotiate the use
−
  of the WebSocket JMAP subprotocol during the WebSocket handshake,
+
of the WebSocket JMAP subprotocol during the WebSocket handshake,
−
  either via an HTTP/1.1 Upgrade request (see Section 4 of [RFC6455])
+
either via an HTTP/1.1 Upgrade request (see Section 4 of [RFC6455])
−
  or an HTTP/2 Extended CONNECT request (see Section 5 of [RFC8441]).
+
or an HTTP/2 Extended CONNECT request (see Section 5 of [RFC8441]).
−
  The WebSocket JMAP subprotocol is also intended to run over future
+
The WebSocket JMAP subprotocol is also intended to run over future
−
  bindings of HTTP (e.g., HTTP/3) provided that there is a defined
+
bindings of HTTP (e.g., HTTP/3) provided that there is a defined
−
  mechanism for performing a WebSocket handshake over that binding.
+
mechanism for performing a WebSocket handshake over that binding.
  
−
  Regardless of the method used for the WebSocket handshake, the client
+
Regardless of the method used for the WebSocket handshake, the client
−
  MUST first perform a TLS handshake on a JMAP WebSocket URL endpoint
+
MUST first perform a TLS handshake on a JMAP WebSocket URL endpoint
−
  (Section 3) having the "wss://" scheme (WebSocket over TLS) in
+
(Section 3) having the "wss://" scheme (WebSocket over TLS) in
−
  accordance with the requirements of running the particular binding of
+
accordance with the requirements of running the particular binding of
−
  HTTP over TLS (see [RFC2818] and Section 4.1 of [RFC6455] for
+
HTTP over TLS (see [RFC2818] and Section 4.1 of [RFC6455] for
−
  HTTP/1.1 and Section 9.2 of [RFC7540] for HTTP/2).  If the TLS
+
HTTP/1.1 and Section 9.2 of [RFC7540] for HTTP/2).  If the TLS
−
  handshake fails, the client MUST close the connection.  Otherwise,
+
handshake fails, the client MUST close the connection.  Otherwise,
−
  the client MUST make an authenticated HTTP request [RFC7235] on the
+
the client MUST make an authenticated HTTP request [RFC7235] on the
−
  encrypted connection and MUST include the value "jmap" in the list of
+
encrypted connection and MUST include the value "jmap" in the list of
−
  protocols for the "Sec-WebSocket-Protocol" header field.
+
protocols for the "Sec-WebSocket-Protocol" header field.
  
−
  The reply from the server MUST also contain a corresponding "Sec-
+
The reply from the server MUST also contain a corresponding "Sec-
−
  WebSocket-Protocol" header field with a value of "jmap" in order for
+
WebSocket-Protocol" header field with a value of "jmap" in order for
−
  a JMAP subprotocol connection to be established.
+
a JMAP subprotocol connection to be established.
  
−
  Once the handshake has successfully completed, the WebSocket
+
Once the handshake has successfully completed, the WebSocket
−
  connection is established and can be used for JMAP API requests,
+
connection is established and can be used for JMAP API requests,
−
  responses, and optional push notifications.  Other message types MUST
+
responses, and optional push notifications.  Other message types MUST
−
  NOT be transmitted over this connection.
+
NOT be transmitted over this connection.
  
−
  The credentials used for authenticating the HTTP request to initiate
+
The credentials used for authenticating the HTTP request to initiate
−
  the handshake remain in effect for the duration of the WebSocket
+
the handshake remain in effect for the duration of the WebSocket
−
  connection.  If the authentication credentials for the user expire,
+
connection.  If the authentication credentials for the user expire,
−
  the server can either treat subsequent requests as if they are
+
the server can either treat subsequent requests as if they are
−
  unauthenticated or close the WebSocket connection.  In the latter
+
unauthenticated or close the WebSocket connection.  In the latter
−
  case, the server MAY send a Close frame with a status code of 1008
+
case, the server MAY send a Close frame with a status code of 1008
−
  (Policy Violation), as defined in Section 7.4.1 of [RFC6455].
+
(Policy Violation), as defined in Section 7.4.1 of [RFC6455].
  
−
4.3.  WebSocket Messages
+
=== WebSocket Messages ===
  
−
  Data frame messages in the JMAP subprotocol MUST be text frames and
+
Data frame messages in the JMAP subprotocol MUST be text frames and
−
  contain UTF-8 encoded data.  The messages MUST be in the form of a
+
contain UTF-8 encoded data.  The messages MUST be in the form of a
−
  single JMAP Request object (see Section 3.3 of [RFC8620]), JMAP
+
single JMAP Request object (see Section 3.3 of [RFC8620]), JMAP
−
  WebSocketPushEnable object (see Section 4.3.5.2), or JMAP
+
WebSocketPushEnable object (see Section 4.3.5.2), or JMAP
−
  WebSocketPushDisable object (see Section 4.3.5.3) when sent from the
+
WebSocketPushDisable object (see Section 4.3.5.3) when sent from the
−
  client to the server, and MUST be in the form of a single JMAP
+
client to the server, and MUST be in the form of a single JMAP
−
  Response object, JSON Problem Details object, or JMAP StateChange
+
Response object, JSON Problem Details object, or JMAP StateChange
−
  object (see Sections 3.4, 3.6.1, and 7.1 of [RFC8620], respectively)
+
object (see Sections 3.4, 3.6.1, and 7.1 of [RFC8620], respectively)
−
  when sent from the server to the client.
+
when sent from the server to the client.
  
−
  Note that fragmented WebSocket messages (split over multiple text
+
Note that fragmented WebSocket messages (split over multiple text
−
  frames) MUST be coalesced prior to parsing them as JSON objects.
+
frames) MUST be coalesced prior to parsing them as JSON objects.
  
−
4.3.1.  Handling Invalid Data
+
==== Handling Invalid Data ====
  
−
  If a client or server receives a binary frame, the endpoint can
+
If a client or server receives a binary frame, the endpoint can
−
  either ignore the frame or close the WebSocket connection.  In the
+
either ignore the frame or close the WebSocket connection.  In the
−
  latter case, the endpoint MAY send a Close frame with a status code
+
latter case, the endpoint MAY send a Close frame with a status code
−
  of 1003 (Unsupported Data), as defined in Section 7.4.1 of [RFC6455].
+
of 1003 (Unsupported Data), as defined in Section 7.4.1 of [RFC6455].
  
−
  If a client receives a message that is not in the form of a JSON
+
If a client receives a message that is not in the form of a JSON
−
  Problem Details object, a JMAP Response object, or a JMAP StateChange
+
Problem Details object, a JMAP Response object, or a JMAP StateChange
−
  object, the client can either ignore the message or close the
+
object, the client can either ignore the message or close the
−
  WebSocket connection.  In the latter case, the endpoint MAY send a
+
WebSocket connection.  In the latter case, the endpoint MAY send a
−
  Close frame with a status code of 1007 (Invalid frame payload data),
+
Close frame with a status code of 1007 (Invalid frame payload data),
−
  as defined in Section 7.4.1 of [RFC6455].
+
as defined in Section 7.4.1 of [RFC6455].
  
−
  A server MUST return an appropriate JSON Problem Details object
+
A server MUST return an appropriate JSON Problem Details object
−
  (Section 4.3.4) for any request-level errors (e.g., an invalid JMAP
+
(Section 4.3.4) for any request-level errors (e.g., an invalid JMAP
−
  object, an unsupported capability or method call, or exceeding a
+
object, an unsupported capability or method call, or exceeding a
−
  server request limit).
+
server request limit).
  
−
4.3.2.  JMAP Requests
+
==== JMAP Requests ====
  
−
  The specification extends the Request object with two additional
+
The specification extends the Request object with two additional
−
  arguments when used over a WebSocket:
+
arguments when used over a WebSocket:
  
−
  *  @type: "String"
+
*  @type: "String"
  
−
      This MUST be the string "Request".
+
  This MUST be the string "Request".
  
−
  *  id: "String" (optional)
+
*  id: "String" (optional)
  
−
      A client-specified identifier for the request to be echoed back in
+
  A client-specified identifier for the request to be echoed back in
−
      the response to this request.
+
  the response to this request.
  
−
  JMAP over WebSocket allows the server to process requests out of
+
JMAP over WebSocket allows the server to process requests out of
−
  order.  The client-specified identifier is used as a mechanism for
+
order.  The client-specified identifier is used as a mechanism for
−
  the client to correlate requests and responses.
+
the client to correlate requests and responses.
  
−
  Additionally, the "maxConcurrentRequests" limit in the "capabilities"
+
Additionally, the "maxConcurrentRequests" limit in the "capabilities"
−
  object (see Section 2 of [RFC8620]) also applies to requests made on
+
object (see Section 2 of [RFC8620]) also applies to requests made on
−
  the WebSocket connection.  When using the WebSocket JMAP subprotocol
+
the WebSocket connection.  When using the WebSocket JMAP subprotocol
−
  over a binding of HTTP that allows multiplexing of requests (e.g.,
+
over a binding of HTTP that allows multiplexing of requests (e.g.,
−
  HTTP/2), this limit applies to the sum of requests made on both the
+
HTTP/2), this limit applies to the sum of requests made on both the
−
  JMAP API endpoint and the WebSocket connection.
+
JMAP API endpoint and the WebSocket connection.
  
−
4.3.3.  JMAP Responses
+
==== JMAP Responses ====
  
−
  The specification extends the Response object with two additional
+
The specification extends the Response object with two additional
−
  arguments when used over a WebSocket:
+
arguments when used over a WebSocket:
  
−
  *  @type: "String"
+
*  @type: "String"
  
−
      This MUST be the string "Response".
+
  This MUST be the string "Response".
  
−
  *  requestId: "String" (optional; MUST be returned if an identifier
+
*  requestId: "String" (optional; MUST be returned if an identifier
−
      is included in the request)
+
  is included in the request)
  
−
      The client-specified identifier in the corresponding request.
+
  The client-specified identifier in the corresponding request.
  
−
4.3.4.  JMAP Request-Level Errors
+
==== JMAP Request-Level Errors ====
  
−
  The specification extends the Problem Details object for request-
+
The specification extends the Problem Details object for request-
−
  level errors (see Section 3.6.1 of [RFC8620]) with two additional
+
level errors (see Section 3.6.1 of [RFC8620]) with two additional
−
  arguments when used over a WebSocket:
+
arguments when used over a WebSocket:
  
−
  *  @type: "String"
+
*  @type: "String"
  
−
      This MUST be the string "RequestError".
+
  This MUST be the string "RequestError".
  
−
  *  requestId: "String" (optional; MUST be returned if given in the
+
*  requestId: "String" (optional; MUST be returned if given in the
−
      request)
+
  request)
  
−
      The client-specified identifier in the corresponding request.
+
  The client-specified identifier in the corresponding request.
  
−
4.3.5.  JMAP Push Notifications
+
==== JMAP Push Notifications ====
  
−
  JMAP-over-WebSocket servers that support push notifications on the
+
JMAP-over-WebSocket servers that support push notifications on the
−
  WebSocket will advertise a "supportsPush" property with a value of
+
WebSocket will advertise a "supportsPush" property with a value of
−
  true in the "urn:ietf:params:jmap:websocket" server capabilities
+
true in the "urn:ietf:params:jmap:websocket" server capabilities
−
  object.
+
object.
  
−
4.3.5.1.  Notification Format
+
===== Notification Format =====
  
−
  All push notifications take the form of a standard StateChange object
+
All push notifications take the form of a standard StateChange object
−
  (see Section 7.1 of [RFC8620]).
+
(see Section 7.1 of [RFC8620]).
  
−
  The specification extends the StateChange object with one additional
+
The specification extends the StateChange object with one additional
−
  argument when used over a WebSocket:
+
argument when used over a WebSocket:
  
−
  *  pushState: "String" (optional)
+
*  pushState: "String" (optional)
  
−
      A (preferably short) string that encodes the entire server state
+
  A (preferably short) string that encodes the entire server state
−
      visible to the user (not just the objects returned in this call).
+
  visible to the user (not just the objects returned in this call).
  
−
      The purpose of the "pushState" token is to allow a client to
+
  The purpose of the "pushState" token is to allow a client to
−
      immediately get any changes that occurred while it was
+
  immediately get any changes that occurred while it was
−
      disconnected (see Section 4.3.5.2).  If the server does not
+
  disconnected (see Section 4.3.5.2).  If the server does not
−
      support "pushState" tokens, the client will have to issue a series
+
  support "pushState" tokens, the client will have to issue a series
−
      of "/changes" requests (see Section 5.2 of [RFC8620]) upon
+
  of "/changes" requests (see Section 5.2 of [RFC8620]) upon
−
      reconnection to update its state to match that of the server.
+
  reconnection to update its state to match that of the server.
  
−
4.3.5.2.  Enabling Notifications
+
===== Enabling Notifications =====
  
−
  A client enables push notifications from the server for the current
+
A client enables push notifications from the server for the current
−
  connection by sending a WebSocketPushEnable object to the server.  A
+
connection by sending a WebSocketPushEnable object to the server.  A
−
  WebSocketPushEnable object has the following properties:
+
WebSocketPushEnable object has the following properties:
  
−
  *  @type: "String"
+
*  @type: "String"
  
−
      This MUST be the string "WebSocketPushEnable".
+
  This MUST be the string "WebSocketPushEnable".
  
−
  *  dataTypes: "String[]|null"
+
*  dataTypes: "String[]|null"
  
−
      A list of data type names (e.g., "Mailbox" or "Email") that the
+
  A list of data type names (e.g., "Mailbox" or "Email") that the
−
      client is interested in.  A StateChange notification will only be
+
  client is interested in.  A StateChange notification will only be
−
      sent if the data for one of these types changes.  Other types are
+
  sent if the data for one of these types changes.  Other types are
−
      omitted from the TypeState object.  If null, changes will be
+
  omitted from the TypeState object.  If null, changes will be
−
      pushed for all supported data types.
+
  pushed for all supported data types.
  
−
  *  pushState: "String" (optional)
+
*  pushState: "String" (optional)
  
−
      The last "pushState" token that the client received from the
+
  The last "pushState" token that the client received from the
−
      server.  Upon receipt of a "pushState" token, the server SHOULD
+
  server.  Upon receipt of a "pushState" token, the server SHOULD
−
      immediately send all changes since that state token.
+
  immediately send all changes since that state token.
  
−
4.3.5.3.  Disabling Notifications
+
===== Disabling Notifications =====
  
−
  A client disables push notifications from the server for the current
+
A client disables push notifications from the server for the current
−
  connection by sending a WebSocketPushDisable object to the server.  A
+
connection by sending a WebSocketPushDisable object to the server.  A
−
  WebSocketPushDisable object has the following property:
+
WebSocketPushDisable object has the following property:
  
−
  *  @type: "String"
+
*  @type: "String"
  
−
      This MUST be the string "WebSocketPushDisable".
+
  This MUST be the string "WebSocketPushDisable".
  
−
4.4.  Examples
+
=== Examples ===
  
−
  The following examples show WebSocket JMAP opening handshakes, a JMAP
+
The following examples show WebSocket JMAP opening handshakes, a JMAP
−
  Core/echo request and response, and a subsequent closing handshake.
+
Core/echo request and response, and a subsequent closing handshake.
−
  The examples assume that the JMAP WebSocket URL endpoint has been
+
The examples assume that the JMAP WebSocket URL endpoint has been
−
  advertised in the JMAP Session object as having a path of "/jmap/ws/"
+
advertised in the JMAP Session object as having a path of "/jmap/ws/"
−
  and that TLS negotiation has already succeeded.  Note that folding of
+
and that TLS negotiation has already succeeded.  Note that folding of
−
  header fields is for editorial purposes only.
+
header fields is for editorial purposes only.
  
−
  WebSocket JMAP connection via HTTP/1.1 with push notifications for
+
WebSocket JMAP connection via HTTP/1.1 with push notifications for
−
  mail [RFC8621] is enabled.  This example assumes that the client has
+
mail [RFC8621] is enabled.  This example assumes that the client has
−
  cached pushState "aaa" from a previous connection.
+
cached pushState "aaa" from a previous connection.
  
−
  [[ From Client ]]                [[ From Server ]]
+
[[ From Client ]]                [[ From Server ]]
  
−
  GET /jmap/ws/ HTTP/1.1
+
GET /jmap/ws/ HTTP/1.1
−
  Host: server.example.com
+
Host: server.example.com
−
  Upgrade: websocket
+
Upgrade: websocket
−
  Connection: Upgrade
+
Connection: Upgrade
−
  Authorization: Basic Zm9vOmJhcg==
+
Authorization: Basic Zm9vOmJhcg==
−
  Sec-WebSocket-Key:
+
Sec-WebSocket-Key:
−
    dGhlIHNhbXBsZSBub25jZQ==
+
  dGhlIHNhbXBsZSBub25jZQ==
−
  Sec-WebSocket-Protocol: jmap
+
Sec-WebSocket-Protocol: jmap
−
  Sec-WebSocket-Version: 13
+
Sec-WebSocket-Version: 13
−
  Origin: https://www.example.com
+
Origin: https://www.example.com
  
−
                                    HTTP/1.1 101 Switching Protocols
+
                                HTTP/1.1 101 Switching Protocols
−
                                    Upgrade: websocket
+
                                Upgrade: websocket
−
                                    Connection: Upgrade
+
                                Connection: Upgrade
−
                                    Sec-WebSocket-Accept:
+
                                Sec-WebSocket-Accept:
−
                                      s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
+
                                  s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
−
                                    Sec-WebSocket-Protocol: jmap
+
                                Sec-WebSocket-Protocol: jmap
  
−
  [WebSocket connection established]
+
[WebSocket connection established]
  
−
  WS_DATA
+
WS_DATA
−
  {
+
{
−
    "@type": "WebSocketPushEnable",
+
  "@type": "WebSocketPushEnable",
−
    "dataTypes": [ "Mailbox", "Email" ],
+
  "dataTypes": [ "Mailbox", "Email" ],
−
    "pushState": "aaa"
+
  "pushState": "aaa"
−
  }
+
}
  
−
                                    WS_DATA
+
                                WS_DATA
−
                                    {
+
                                {
−
                                      "@type": "StateChange",
+
                                  "@type": "StateChange",
−
                                      "changed": {
+
                                  "changed": {
−
                                        "a456": {
+
                                    "a456": {
−
                                          "Mailbox": "d35ecb040aab"
+
                                      "Mailbox": "d35ecb040aab"
−
                                        }
+
                                    }
−
                                      },
+
                                  },
−
                                      "pushState": "bbb"
+
                                  "pushState": "bbb"
−
                                    }
+
                                }
  
−
  WS_DATA
+
WS_DATA
−
  {
+
{
−
    "@type": "Request",
+
  "@type": "Request",
−
    "id": "R1",
+
  "id": "R1",
−
    "using": [ "urn:ietf:params:jmap:core" ],
+
  "using": [ "urn:ietf:params:jmap:core" ],
−
    "methodCalls": [
+
  "methodCalls": [
−
      [
+
    [
−
        "Core/echo", {
+
      "Core/echo", {
−
          "hello": true,
+
        "hello": true,
−
          "high": 5
+
        "high": 5
−
        },
+
      },
−
        "b3ff"
+
      "b3ff"
−
      ]
+
    ]
−
    ]
+
  ]
−
  }
+
}
  
−
                                    WS_DATA
+
                                WS_DATA
−
                                    {
+
                                {
−
                                      "@type": "Response",
+
                                  "@type": "Response",
−
                                      "requestId": "R1",
+
                                  "requestId": "R1",
−
                                      "methodResponses": [
+
                                  "methodResponses": [
−
                                        [
+
                                    [
−
                                          "Core/echo", {
+
                                      "Core/echo", {
−
                                            "hello": true,
+
                                        "hello": true,
−
                                            "high": 5
+
                                        "high": 5
−
                                          },
+
                                      },
−
                                          "b3ff"
+
                                      "b3ff"
−
                                        ]
+
                                    ]
−
                                      ]
+
                                  ]
−
                                    }
+
                                }
  
−
  WS_DATA
+
WS_DATA
−
  The quick brown fox jumps
+
The quick brown fox jumps
−
    over the lazy dog.
+
over the lazy dog.
  
−
                                    WS_DATA
+
                                WS_DATA
−
                                    {
+
                                {
−
                                      "@type": "RequestError",
+
                                  "@type": "RequestError",
−
                                      "requestId": null,
+
                                  "requestId": null,
−
                                      "type":
+
                                  "type":
−
                                "urn:ietf:params:jmap:error:notJSON",
+
                            "urn:ietf:params:jmap:error:notJSON",
−
                                      "status": 400,
+
                                  "status": 400,
−
                                      "detail":
+
                                  "detail":
−
                                "The request did not parse as I-JSON."
+
                            "The request did not parse as I-JSON."
−
                                    }
+
                                }
  
−
  [A new email is received]
+
[A new email is received]
  
−
                                    WS_DATA
+
                                WS_DATA
−
                                    {
+
                                {
−
                                      "@type": "StateChange",
+
                                  "@type": "StateChange",
−
                                      "changed": {
+
                                  "changed": {
−
                                        "a123": {
+
                                    "a123": {
−
                                          "Email": "0af7a512ce70"
+
                                      "Email": "0af7a512ce70"
−
                                        }
+
                                    }
−
                                      }
+
                                  }
−
                                      "pushState": "ccc"
+
                                  "pushState": "ccc"
−
                                    }
+
                                }
  
−
  WS_CLOSE
+
WS_CLOSE
  
−
                                    WS_CLOSE
+
                                WS_CLOSE
  
−
  [WebSocket connection closed]
+
[WebSocket connection closed]
  
−
  WebSocket JMAP connection on an HTTP/2 stream that also negotiates
+
WebSocket JMAP connection on an HTTP/2 stream that also negotiates
−
  compression [RFC7692]:
+
compression [RFC7692]:
  
−
  [[ From Client ]]                [[ From Server ]]
+
[[ From Client ]]                [[ From Server ]]
  
−
                                    SETTINGS
+
                                SETTINGS
−
                                    SETTINGS_ENABLE_CONNECT_PROTOCOL = 1
+
                                SETTINGS_ENABLE_CONNECT_PROTOCOL = 1
  
−
  HEADERS + END_HEADERS
+
HEADERS + END_HEADERS
−
  :method = CONNECT
+
:method = CONNECT
−
  :protocol = websocket
+
:protocol = websocket
−
  :scheme = https
+
:scheme = https
−
  :path = /jmap/ws/
+
:path = /jmap/ws/
−
  :authority = server.example.com
+
:authority = server.example.com
−
  origin: https://example.com
+
origin: https://example.com
−
  authorization = Basic Zm9vOmJhcg==
+
authorization = Basic Zm9vOmJhcg==
−
  sec-websocket-protocol = jmap
+
sec-websocket-protocol = jmap
−
  sec-websocket-version = 13
+
sec-websocket-version = 13
−
  sec-websocket-extensions =
+
sec-websocket-extensions =
−
    permessage-deflate
+
  permessage-deflate
−
  origin = https://www.example.com
+
origin = https://www.example.com
  
−
                                    HEADERS + END_HEADERS
+
                                HEADERS + END_HEADERS
−
                                    :status = 200
+
                                :status = 200
−
                                    sec-websocket-protocol = jmap
+
                                sec-websocket-protocol = jmap
−
                                    sec-websocket-extensions =
+
                                sec-websocket-extensions =
−
                                      permessage-deflate
+
                                  permessage-deflate
  
−
  [WebSocket connection established]
+
[WebSocket connection established]
  
−
  DATA
+
DATA
−
  WS_DATA
+
WS_DATA
−
  [compressed text]
+
[compressed text]
  
−
                                    DATA
+
                                DATA
−
                                    WS_DATA
+
                                WS_DATA
−
                                    [compressed text]
+
                                [compressed text]
  
−
  ...
+
...
  
−
  DATA + END_STREAM
+
DATA + END_STREAM
−
  WS_CLOSE
+
WS_CLOSE
  
−
                                    DATA + END_STREAM
+
                                DATA + END_STREAM
−
                                    WS_CLOSE
+
                                WS_CLOSE
  
−
  [WebSocket connection closed]
+
[WebSocket connection closed]
−
  [HTTP/2 stream closed]
+
[HTTP/2 stream closed]
  
−
5.  Security Considerations
+
== Security Considerations ==
  
−
  The security considerations for both WebSocket (see Section 10 of
+
The security considerations for both WebSocket (see Section 10 of
−
  [RFC6455]) and JMAP (see Section 8 of [RFC8620]) apply to the
+
[RFC6455]) and JMAP (see Section 8 of [RFC8620]) apply to the
−
  WebSocket JMAP subprotocol.  Specific security considerations are
+
WebSocket JMAP subprotocol.  Specific security considerations are
−
  described below.
+
described below.
  
−
5.1.  Connection Confidentiality and Integrity
+
=== Connection Confidentiality and Integrity ===
  
−
  To ensure the confidentiality and integrity of data sent and received
+
To ensure the confidentiality and integrity of data sent and received
−
  via JMAP over WebSocket, the WebSocket connection MUST use TLS 1.2
+
via JMAP over WebSocket, the WebSocket connection MUST use TLS 1.2
−
  [RFC5246] or later, following the recommendations in BCP 195
+
[RFC5246] or later, following the recommendations in BCP 195
−
  [RFC7525].  Servers SHOULD support TLS 1.3 [RFC8446] or later.
+
[RFC7525].  Servers SHOULD support TLS 1.3 [RFC8446] or later.
  
−
5.2.  Non-browser Clients
+
=== Non-browser Clients ===
  
−
  JMAP over WebSocket can be used by clients both running inside and
+
JMAP over WebSocket can be used by clients both running inside and
−
  outside of a web browser.  As such, the security considerations in
+
outside of a web browser.  As such, the security considerations in
−
  Sections 10.2 and 10.1 of [RFC6455] apply to those respective
+
Sections 10.2 and 10.1 of [RFC6455] apply to those respective
−
  environments.
+
environments.
  
−
6.  IANA Considerations
+
== IANA Considerations ==
  
−
6.1.  Registration of the WebSocket JMAP Subprotocol
+
=== Registration of the WebSocket JMAP Subprotocol ===
  
−
  Per this specification, IANA has registered the following in the
+
Per this specification, IANA has registered the following in the
−
  "WebSocket Subprotocol Name Registry" within the "WebSocket Protocol
+
"WebSocket Subprotocol Name Registry" within the "WebSocket Protocol
−
  Registries".
+
Registries".
  
−
  Subprotocol Identifier:  jmap
+
Subprotocol Identifier:  jmap
  
−
  Subprotocol Common Name:  WebSocket Transport for JMAP (JSON Meta
+
Subprotocol Common Name:  WebSocket Transport for JMAP (JSON Meta
−
      Application Protocol)
+
  Application Protocol)
  
−
  Subprotocol Definition:  RFC 8887
+
Subprotocol Definition:  RFC 8887
  
−
7.  References
+
== References ==
  
−
7.1.  Normative References
+
=== Normative References ===
  
−
  [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
+
[RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
−
              Requirement Levels", BCP 14, RFC 2119,
+
          Requirement Levels", BCP 14, RFC 2119,
−
              DOI 10.17487/RFC2119, March 1997,
+
          DOI 10.17487/RFC2119, March 1997,
−
              <https://www.rfc-editor.org/info/rfc2119>.
+
          <https://www.rfc-editor.org/info/rfc2119>.
  
−
  [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818,
+
[RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818,
−
              DOI 10.17487/RFC2818, May 2000,
+
          DOI 10.17487/RFC2818, May 2000,
−
              <https://www.rfc-editor.org/info/rfc2818>.
+
          <https://www.rfc-editor.org/info/rfc2818>.
  
−
  [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
+
[RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
−
              (TLS) Protocol Version 1.2", RFC 5246,
+
          (TLS) Protocol Version 1.2", RFC 5246,
−
              DOI 10.17487/RFC5246, August 2008,
+
          DOI 10.17487/RFC5246, August 2008,
−
              <https://www.rfc-editor.org/info/rfc5246>.
+
          <https://www.rfc-editor.org/info/rfc5246>.
  
−
  [RFC6455]  Fette, I. and A. Melnikov, "The WebSocket Protocol",
+
[RFC6455]  Fette, I. and A. Melnikov, "The WebSocket Protocol",
−
              RFC 6455, DOI 10.17487/RFC6455, December 2011,
+
          RFC 6455, DOI 10.17487/RFC6455, December 2011,
−
              <https://www.rfc-editor.org/info/rfc6455>.
+
          <https://www.rfc-editor.org/info/rfc6455>.
  
−
  [RFC7235]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
+
[RFC7235]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
−
              Protocol (HTTP/1.1): Authentication", RFC 7235,
+
          Protocol (HTTP/1.1): Authentication", RFC 7235,
−
              DOI 10.17487/RFC7235, June 2014,
+
          DOI 10.17487/RFC7235, June 2014,
−
              <https://www.rfc-editor.org/info/rfc7235>.
+
          <https://www.rfc-editor.org/info/rfc7235>.
  
−
  [RFC7525]  Sheffer, Y., Holz, R., and P. Saint-Andre,
+
[RFC7525]  Sheffer, Y., Holz, R., and P. Saint-Andre,
−
              "Recommendations for Secure Use of Transport Layer
+
          "Recommendations for Secure Use of Transport Layer
−
              Security (TLS) and Datagram Transport Layer Security
+
          Security (TLS) and Datagram Transport Layer Security
−
              (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
+
          (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
−
              2015, <https://www.rfc-editor.org/info/rfc7525>.
+
          2015, <https://www.rfc-editor.org/info/rfc7525>.
  
−
  [RFC7540]  Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
+
[RFC7540]  Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
−
              Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
+
          Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
−
              DOI 10.17487/RFC7540, May 2015,
+
          DOI 10.17487/RFC7540, May 2015,
−
              <https://www.rfc-editor.org/info/rfc7540>.
+
          <https://www.rfc-editor.org/info/rfc7540>.
  
−
  [RFC7692]  Yoshino, T., "Compression Extensions for WebSocket",
+
[RFC7692]  Yoshino, T., "Compression Extensions for WebSocket",
−
              RFC 7692, DOI 10.17487/RFC7692, December 2015,
+
          RFC 7692, DOI 10.17487/RFC7692, December 2015,
−
              <https://www.rfc-editor.org/info/rfc7692>.
+
          <https://www.rfc-editor.org/info/rfc7692>.
  
−
  [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
+
[RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
−
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
+
          2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
−
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.
+
          May 2017, <https://www.rfc-editor.org/info/rfc8174>.
  
−
  [RFC8441]  McManus, P., "Bootstrapping WebSockets with HTTP/2",
+
[RFC8441]  McManus, P., "Bootstrapping WebSockets with HTTP/2",
−
              RFC 8441, DOI 10.17487/RFC8441, September 2018,
+
          RFC 8441, DOI 10.17487/RFC8441, September 2018,
−
              <https://www.rfc-editor.org/info/rfc8441>.
+
          <https://www.rfc-editor.org/info/rfc8441>.
  
−
  [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
+
[RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
−
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
+
          Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
−
              <https://www.rfc-editor.org/info/rfc8446>.
+
          <https://www.rfc-editor.org/info/rfc8446>.
  
−
  [RFC8620]  Jenkins, N. and C. Newman, "The JSON Meta Application
+
[RFC8620]  Jenkins, N. and C. Newman, "The JSON Meta Application
−
              Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July
+
          Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July
−
              2019, <https://www.rfc-editor.org/info/rfc8620>.
+
          2019, <https://www.rfc-editor.org/info/rfc8620>.
  
−
7.2.  Informative References
+
=== Informative References ===
  
−
  [RFC8621]  Jenkins, N. and C. Newman, "The JSON Meta Application
+
[RFC8621]  Jenkins, N. and C. Newman, "The JSON Meta Application
−
              Protocol (JMAP) for Mail", RFC 8621, DOI 10.17487/RFC8621,
+
          Protocol (JMAP) for Mail", RFC 8621, DOI 10.17487/RFC8621,
−
              August 2019, <https://www.rfc-editor.org/info/rfc8621>.
+
          August 2019, <https://www.rfc-editor.org/info/rfc8621>.
  
 
Acknowledgments
 
Acknowledgments
  
−
  The author would like to thank the following individuals for
+
The author would like to thank the following individuals for
−
  contributing their ideas and support for writing this specification:
+
contributing their ideas and support for writing this specification:
−
  Neil Jenkins, Robert Mueller, and Chris Newman.
+
Neil Jenkins, Robert Mueller, and Chris Newman.
  
 
Author's Address
 
Author's Address
  
−
  Kenneth Murchison
+
Kenneth Murchison
−
  Fastmail US LLC
+
Fastmail US LLC
−
  1429 Walnut Street, Suite 1201
+
1429 Walnut Street, Suite 1201
−
  Philadelphia, PA 19102
+
Philadelphia, PA 19102
−
  United States of America
+
United States of America
  
−+
−
  URI:  http://www.fastmail.com/
+
URI:  http://www.fastmail.com/

Revision as of 13:12, 27 September 2020



Internet Engineering Task Force (IETF) K. Murchison Request for Comments: 8887 Fastmail Category: Standards Track August 2020 ISSN: 2070-1721

A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket

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 is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8887.

Copyright Notice

Copyright (c) 2020 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.

Table of Contents

1. Introduction 2. Conventions Used in This Document 3. Discovering Support for JMAP over WebSocket 4. JMAP Subprotocol 

 4.1.  Authentication
 4.2.  Handshake
 4.3.  WebSocket Messages
   4.3.1.  Handling Invalid Data
   4.3.2.  JMAP Requests
   4.3.3.  JMAP Responses
   4.3.4.  JMAP Request-Level Errors
   4.3.5.  JMAP Push Notifications
 4.4.  Examples

5. Security Considerations 

 5.1.  Connection Confidentiality and Integrity
 5.2.  Non-browser Clients

6. IANA Considerations 

 6.1.  Registration of the WebSocket JMAP Subprotocol

7. References 

 7.1.  Normative References
 7.2.  Informative References

Acknowledgments Author's Address

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, reauthenticating for 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.

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.

This document uses the terminology defined in the core JMAP specification [RFC8620].

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 that MUST contain the following information on server capabilities:

  • url: "String"
  The wss-URI (see Section 3 of [RFC6455]) to use for initiating a
  JMAP-over-WebSocket handshake (the "WebSocket URL endpoint"
  colloquially).
  • supportsPush: "Boolean"
  This is true if the server supports push notifications over the
  WebSocket, as described in Section 4.3.5.

Example:

"urn:ietf:params:jmap:websocket": { 

 "url": "wss://server.example.com/jmap/ws/",
 "supportsPush": true

}

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 is handled per Section 6 of [RFC8620] (via a separate HTTP connection or stream) or per a future extension to JMAP or this specification.

Authentication

A JMAP WebSocket connection is authenticated by presenting a user's credentials in the HTTP request [RFC7235] that initiates the WebSocket handshake. See Section 8.2 of [RFC8620] for recommendations regarding the selection of HTTP authentication schemes.

Handshake

The JMAP WebSocket client and JMAP WebSocket server negotiate the use of the WebSocket JMAP subprotocol during the WebSocket handshake, either via an HTTP/1.1 Upgrade request (see Section 4 of [RFC6455]) or an HTTP/2 Extended CONNECT request (see Section 5 of [RFC8441]). The WebSocket JMAP subprotocol is also intended to run over future bindings of HTTP (e.g., HTTP/3) provided that there is a defined mechanism for performing a WebSocket handshake over that binding.

Regardless of the method used for the WebSocket handshake, the client MUST first perform a TLS handshake on a JMAP WebSocket URL endpoint (Section 3) having the "wss://" scheme (WebSocket over TLS) in accordance with the requirements of running the particular binding of HTTP over TLS (see [RFC2818] and Section 4.1 of [RFC6455] for HTTP/1.1 and Section 9.2 of [RFC7540] for HTTP/2). If the TLS handshake fails, the client MUST close the connection. Otherwise, the client MUST make an authenticated HTTP request [RFC7235] on the encrypted connection and 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 a corresponding "Sec- WebSocket-Protocol" header field with a value of "jmap" in order for a JMAP subprotocol connection to be established.

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. If the authentication credentials for the user expire, the server can either treat subsequent requests as if they are unauthenticated or close the WebSocket connection. In the latter case, the server MAY send a Close frame with a status code of 1008 (Policy Violation), as defined in Section 7.4.1 of [RFC6455].

WebSocket Messages

Data frame messages in the JMAP subprotocol MUST be text frames and contain UTF-8 encoded data. The messages MUST be in the form of a single JMAP Request object (see Section 3.3 of [RFC8620]), JMAP WebSocketPushEnable object (see Section 4.3.5.2), or JMAP WebSocketPushDisable object (see Section 4.3.5.3) when sent from the client to the server, and MUST be in the form of a single JMAP Response object, JSON Problem Details object, or JMAP StateChange object (see Sections 3.4, 3.6.1, and 7.1 of [RFC8620], respectively) when sent from the server to the client.

Note that fragmented WebSocket messages (split over multiple text frames) MUST be coalesced prior to parsing them as JSON objects.

Handling Invalid Data

If a client or server receives a binary frame, the endpoint can either ignore the frame or close the WebSocket connection. In the latter case, the endpoint MAY send a Close frame with a status code of 1003 (Unsupported Data), as defined in Section 7.4.1 of [RFC6455].

If a client receives a message that is not in the form of a JSON Problem Details object, a JMAP Response object, or a JMAP StateChange object, the client can either ignore the message or close the WebSocket connection. In the latter case, the endpoint MAY send a Close frame with a status code of 1007 (Invalid frame payload data), as defined in Section 7.4.1 of [RFC6455].

A server MUST return an appropriate JSON Problem Details object (Section 4.3.4) for any request-level errors (e.g., an invalid JMAP object, an unsupported capability or method call, or exceeding a server request limit).

JMAP Requests

The specification extends the Request object with two additional arguments when used over a WebSocket:

  • @type: "String"
  This MUST be the string "Request".
  • id: "String" (optional)
  A client-specified identifier for the request to be echoed back in
  the response to this 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" limit in the "capabilities" object (see Section 2 of [RFC8620]) also applies to requests made on the WebSocket connection. When using the WebSocket JMAP subprotocol over a binding of HTTP that allows multiplexing of requests (e.g., HTTP/2), this limit applies to the sum of requests made on both the JMAP API endpoint and the WebSocket connection.

JMAP Responses

The specification extends the Response object with two additional arguments when used over a WebSocket:

  • @type: "String"
  This MUST be the string "Response".
  • requestId: "String" (optional; MUST be returned if an identifier
  is included in the request)

  The client-specified identifier in the corresponding request.

JMAP Request-Level Errors

The specification extends the Problem Details object for request- level errors (see Section 3.6.1 of [RFC8620]) with two additional arguments when used over a WebSocket:

  • @type: "String"
  This MUST be the string "RequestError".
  • requestId: "String" (optional; MUST be returned if given in the
  request)

  The client-specified identifier in the corresponding request.

JMAP Push Notifications

JMAP-over-WebSocket servers that support push notifications on the WebSocket will advertise a "supportsPush" property with a value of true in the "urn:ietf:params:jmap:websocket" server capabilities object.

Notification Format

All push notifications take the form of a standard StateChange object (see Section 7.1 of [RFC8620]).

The specification extends the StateChange object with one additional argument when used over a WebSocket:

  • pushState: "String" (optional)
  A (preferably short) string that encodes the entire server state
  visible to the user (not just the objects returned in this call).

  The purpose of the "pushState" token is to allow a client to
  immediately get any changes that occurred while it was
  disconnected (see Section 4.3.5.2).  If the server does not
  support "pushState" tokens, the client will have to issue a series
  of "/changes" requests (see Section 5.2 of [RFC8620]) upon
  reconnection to update its state to match that of the server.
Enabling Notifications

A client enables push notifications from the server for the current connection by sending a WebSocketPushEnable object to the server. A WebSocketPushEnable object has the following properties:

  • @type: "String"
  This MUST be the string "WebSocketPushEnable".
  • dataTypes: "String[]|null"
  A list of data type names (e.g., "Mailbox" or "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.
  • 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.
Disabling Notifications

A client disables push notifications from the server for the current connection by sending a WebSocketPushDisable object to the server. A WebSocketPushDisable object has the following property:

  • @type: "String"
  This MUST be the string "WebSocketPushDisable".

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 WebSocket URL endpoint has been advertised in the JMAP Session object as having a path of "/jmap/ws/" and that TLS negotiation has already succeeded. Note that folding of header fields is for editorial purposes only.

WebSocket JMAP connection via HTTP/1.1 with push notifications for mail [RFC8621] is enabled. This example assumes that the client has cached pushState "aaa" from a previous connection.

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: https://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": {
                                      "Mailbox": "d35ecb040aab"
                                    }
                                  },
                                  "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."
                                }

[A new email is received] 

                                WS_DATA
                                {
                                  "@type": "StateChange",
                                  "changed": {
                                    "a123": {
                                      "Email": "0af7a512ce70"
                                    }
                                  }
                                  "pushState": "ccc"
                                }

WS_CLOSE 

                                WS_CLOSE

[WebSocket connection closed]

WebSocket JMAP connection on an HTTP/2 stream that 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

origin: https://example.com authorization = Basic Zm9vOmJhcg== sec-websocket-protocol = jmap sec-websocket-version = 13 sec-websocket-extensions = 

 permessage-deflate

origin = https://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]

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. Specific security considerations are described below.

Connection Confidentiality and Integrity

To ensure the confidentiality and integrity of data sent and received via JMAP over WebSocket, the WebSocket connection MUST use TLS 1.2 [RFC5246] or later, following the recommendations in BCP 195 [RFC7525]. Servers SHOULD support TLS 1.3 [RFC8446] or later.

Non-browser Clients

JMAP over WebSocket can be used by clients both running inside and outside of a web browser. As such, the security considerations in Sections 10.2 and 10.1 of [RFC6455] apply to those respective environments.

IANA Considerations

Registration of the WebSocket JMAP Subprotocol

Per this specification, IANA has registered the following in the "WebSocket Subprotocol Name Registry" within the "WebSocket Protocol Registries".

Subprotocol Identifier: jmap

Subprotocol Common Name: WebSocket Transport for JMAP (JSON Meta 

  Application Protocol)

Subprotocol Definition: RFC 8887

References

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>.

[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 

          DOI 10.17487/RFC2818, May 2000,
          <https://www.rfc-editor.org/info/rfc2818>.

[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 

          (TLS) Protocol Version 1.2", RFC 5246,
          DOI 10.17487/RFC5246, August 2008,
          <https://www.rfc-editor.org/info/rfc5246>.

[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>.

[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, 

          "Recommendations for Secure Use of Transport Layer
          Security (TLS) and Datagram Transport Layer Security
          (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
          2015, <https://www.rfc-editor.org/info/rfc7525>.

[RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext 

          Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
          DOI 10.17487/RFC7540, May 2015,
          <https://www.rfc-editor.org/info/rfc7540>.

[RFC7692] Yoshino, T., "Compression Extensions for WebSocket", 

          RFC 7692, DOI 10.17487/RFC7692, December 2015,
          <https://www.rfc-editor.org/info/rfc7692>.

[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>.

[RFC8441] McManus, P., "Bootstrapping WebSockets with HTTP/2", 

          RFC 8441, DOI 10.17487/RFC8441, September 2018,
          <https://www.rfc-editor.org/info/rfc8441>.

[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol 

          Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
          <https://www.rfc-editor.org/info/rfc8446>.

[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>.

Informative References

[RFC8621] Jenkins, N. and C. Newman, "The JSON Meta Application 

          Protocol (JMAP) for Mail", RFC 8621, DOI 10.17487/RFC8621,
          August 2019, <https://www.rfc-editor.org/info/rfc8621>.

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.

Author's Address

Kenneth Murchison Fastmail US LLC 1429 Walnut Street, Suite 1201 Philadelphia, PA 19102 United States of America

Email: [email protected] URI: http://www.fastmail.com/

Retrieved from "https://www.rfc-wiki.org/index.php?title=RFC8887&oldid=12134"