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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 2818 (Obsoleted by RFC 9110) ** Obsolete normative reference: RFC 5246 (Obsoleted by RFC 8446) ** Obsolete normative reference: RFC 7235 (Obsoleted by RFC 9110) ** Obsolete normative reference: RFC 7525 (Obsoleted by RFC 9325) ** Obsolete normative reference: RFC 7540 (Obsoleted by RFC 9113) Summary: 5 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 JMAP K. Murchison 3 Internet-Draft Fastmail 4 Intended status: Standards Track March 19, 2020 5 Expires: September 20, 2020 7 A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket 8 draft-ietf-jmap-websocket-07 10 Abstract 12 This document defines a binding for the JSON Meta Application 13 Protocol (JMAP) over a WebSocket transport layer. The WebSocket 14 binding for JMAP provides higher performance than the current HTTP 15 binding for JMAP. 17 Status of This Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at https://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on September 20, 2020. 34 Copyright Notice 36 Copyright (c) 2020 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (https://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 2. Conventions Used in This Document . . . . . . . . . . . . . . 3 53 3. Discovering Support for JMAP over WebSocket . . . . . . . . . 3 54 4. JMAP Subprotocol . . . . . . . . . . . . . . . . . . . . . . 3 55 4.1. Authentication . . . . . . . . . . . . . . . . . . . . . 4 56 4.2. Handshake . . . . . . . . . . . . . . . . . . . . . . . . 4 57 4.3. WebSocket Messages . . . . . . . . . . . . . . . . . . . 5 58 4.3.1. Handling Invalid Data . . . . . . . . . . . . . . . . 5 59 4.3.2. JMAP Requests . . . . . . . . . . . . . . . . . . . . 5 60 4.3.3. JMAP Responses . . . . . . . . . . . . . . . . . . . 6 61 4.3.4. JMAP Request-Level Errors . . . . . . . . . . . . . . 6 62 4.3.5. JMAP Push Notifications . . . . . . . . . . . . . . . 6 63 4.4. Examples . . . . . . . . . . . . . . . . . . . . . . . . 8 64 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12 65 5.1. Connection Confidentiality and Integrity . . . . . . . . 12 66 5.2. Non-Browser Clients . . . . . . . . . . . . . . . . . . . 12 67 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 68 6.1. Registration of the WebSocket JMAP Subprotocol . . . . . 12 69 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 70 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 71 8.1. Normative References . . . . . . . . . . . . . . . . . . 13 72 8.2. Informative References . . . . . . . . . . . . . . . . . 14 73 Appendix A. Change History (To be removed by RFC Editor before 74 publication) . . . . . . . . . . . . . . . . . . . . 14 75 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 16 77 1. Introduction 79 JMAP [RFC8620] over HTTP [RFC7235] requires that every JMAP API 80 request be authenticated. Depending on the type of authentication 81 used by the JMAP client and the configuration of the JMAP server, 82 authentication could be an expensive operation both in time and 83 resources. In such circumstances, reauthenticating for every JMAP 84 API request may harm performance. 86 The WebSocket [RFC6455] binding for JMAP eliminates this performance 87 hit by authenticating just the WebSocket handshake request and having 88 those credentials remain in effect for the duration of the WebSocket 89 connection. This binding supports JMAP API requests and responses, 90 with optional support for push notifications. 92 Furthermore, the WebSocket binding for JMAP can optionally compress 93 [RFC7692] both JMAP API requests and responses. Although compression 94 of HTTP responses is ubiquitous, compression of HTTP requests has 95 very low, if any deployment, and therefore isn't a viable option for 96 JMAP API requests over HTTP. 98 2. Conventions Used in This Document 100 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 101 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 102 "OPTIONAL" in this document are to be interpreted as described in 103 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all 104 capitals, as shown here. 106 The same terminology is used in this document as in the core JMAP 107 specification. 109 3. Discovering Support for JMAP over WebSocket 111 The JMAP capabilities object is returned as part of the standard JMAP 112 Session object (see Section 2 of [RFC8620]). Servers supporting this 113 specification MUST add a property named 114 "urn:ietf:params:jmap:websocket" to the capabilities object. The 115 value of this property is an object which MUST contain the following 116 information on server capabilities: 118 o url: "String" 120 The wss-URI (see Section 3 of [RFC6455]) to use for initiating a 121 JMAP over WebSocket handshake (the "WebSocket URL endpoint" 122 colloquially). 124 o supportsPush: "Boolean" 126 This is true if the server supports push notifications over the 127 WebSocket, as described in Section 4.3.5. 129 Example: 131 "urn:ietf:params:jmap:websocket": { 132 "url": "wss://server.example.com/jmap/ws/", 133 "supportsPush": true 134 } 136 4. JMAP Subprotocol 138 The term WebSocket subprotocol refers to an application-level 139 protocol layered on top of a WebSocket connection. This document 140 specifies the WebSocket JMAP subprotocol for carrying JMAP API 141 requests, responses, and optional push notifications through a 142 WebSocket connection. Binary data is handled per Section 6 of 143 [RFC8620] via a separate HTTP connection or stream. 145 4.1. Authentication 147 A JMAP WebSocket connection is authenticated by presenting a user's 148 credentials in the HTTP request [RFC7235] that initiates the 149 WebSocket handshake. See Section 8.2 of [RFC8620] for 150 recommendations regarding the selection of HTTP authentication 151 schemes. 153 4.2. Handshake 155 The JMAP WebSocket client and JMAP WebSocket server negotiate the use 156 of the WebSocket JMAP subprotocol during the WebSocket handshake, 157 either via a HTTP/1.1 Upgrade request (see Section 4 of [RFC6455]) or 158 a HTTP/2 Extended CONNECT request (see Section 5 of [RFC8441]). The 159 WebSocket JMAP subprotocol is also intended to run over future 160 bindings of HTTP (e.g. HTTP/3) provided that there is a defined 161 mechanism for performing a WebSocket handshake over that binding. 163 Regardless of the method used for the WebSocket handshake, the client 164 MUST first perform a TLS handshake on a JMAP WebSocket URL endpoint 165 (Section 3) having the "wss://" scheme (WebSocket over TLS) in 166 accordance with the requirements of running the particular binding of 167 HTTP over TLS (see [RFC2818] and Section 4.1 of [RFC6455] for 168 HTTP/1.1 and Section 9.2 of [RFC7540] for HTTP/2). If the TLS 169 handshake fails, the client MUST close the connection. Otherwise, 170 the client MUST make an authenticated [RFC7235] HTTP request on the 171 encrypted connection, and MUST include the value "jmap" in the list 172 of protocols for the "Sec-WebSocket-Protocol" header field. 174 The reply from the server MUST also contain a corresponding "Sec- 175 WebSocket-Protocol" header field with a value of "jmap" in order for 176 a JMAP subprotocol connection to be established. 178 Once the handshake has successfully completed, the WebSocket 179 connection is established and can be used for JMAP API requests, 180 responses, and optional push notifications. Other message types MUST 181 NOT be transmitted over this connection. 183 The credentials used for authenticating the HTTP request to initiate 184 the handshake remain in effect for the duration of the WebSocket 185 connection. If the authentication credentials for the user expire, 186 the server can either treat subsequent requests as if they are 187 unauthenticated or close the WebSocket connection. In the latter 188 case, the server MAY send a Close frame with a status code of 1008 189 (Policy Violation) as defined in Section 7.4.1 of [RFC6455]. 191 4.3. WebSocket Messages 193 Data frame messages in the JMAP subprotocol MUST be text frames and 194 contain UTF-8 encoded data. The messages MUST be in the form of a 195 single JMAP Request object (see Section 3.3 of [RFC8620]), JMAP 196 WebSocketPushEnable object (see Section 4.3.5.2), or JMAP 197 WebSocketPushDisable object (see Section 4.3.5.3) when sent from the 198 client to the server, and in the form of a single JMAP Response 199 object, JSON Problem Details object, or JMAP StateChange object (see 200 Sections 3.4, 3.6.1, and 7.1 respectively of [RFC8620]) when sent 201 from the server to the client. 203 Note that fragmented WebSocket messages (split over multiple text 204 frames) MUST be coalesced prior to parsing them as JSON objects. 206 4.3.1. Handling Invalid Data 208 If a client or server receives a binary frame, the endpoint can 209 either ignore the frame or close the WebSocket connection. In the 210 latter case, the endpoint MAY send a Close frame with a status code 211 of 1003 (Unsupported Data) as defined in Section 7.4.1 of [RFC6455]. 213 If a client receives a message that is not in the form of either a 214 JSON Problem Details object, a JMAP Response object, or a JMAP 215 StateChange object, the client can either ignore the message or close 216 the WebSocket connection. In the latter case, the endpoint MAY send 217 a Close frame with a status code of 1007 (Invalid frame payload data 218 Data) as defined in Section 7.4.1 of [RFC6455]. 220 A server MUST return an appropriate JSON Problem Details object 221 (Section 4.3.4) for any request-level errors (E.g. an invalid JMAP 222 object, an unsupported capability or method call, or exceeding a 223 server request limit). 225 4.3.2. JMAP Requests 227 The specification extends the Request object with two additional 228 arguments when used over a WebSocket: 230 o @type: "String" 232 This MUST be the string "Request". 234 o id: "String" (optional) 236 A client-specified identifier for the request to be echoed back in 237 the response to this request. 239 JMAP over WebSocket allows the server to process requests out of 240 order. The client-specified identifier is used as a mechanism for 241 the client to correlate requests and responses. 243 Additionally, the "maxConcurrentRequests" limit in the "capabilities" 244 object (see Section 2 of [RFC8620]) also applies to requests made on 245 the WebSocket connection. When using the WebSocket JMAP subprotocol 246 over a binding of HTTP that allows multiplexing of requests (e.g. 247 HTTP/2), this limit applies to the the sum of requests made on both 248 the JMAP API endpoint and the WebSocket connection. 250 4.3.3. JMAP Responses 252 The specification extends the Response object with two additional 253 arguments when used over a WebSocket: 255 o @type: "String" 257 This MUST be the string "Response". 259 o requestId: "String" (optional; MUST be returned if an id is 260 included in the request) 262 The client-specified identifier in the corresponding request. 264 4.3.4. JMAP Request-Level Errors 266 The specification extends the Problem Details object for request- 267 level errors (see Section 3.6.1 of [RFC8620]) with two additional 268 arguments when used over a WebSocket: 270 o @type: "String" 272 This MUST be the string "RequestError". 274 o requestId: "String" (optional; MUST be returned if given in the 275 request) 277 The client-specified identifier in the corresponding request. 279 4.3.5. JMAP Push Notifications 281 JMAP over WebSocket servers that support push notifications on the 282 WebSocket will advertise a "supportsPush" property with a value of 283 true in the "urn:ietf:params:jmap:websocket" server capabilities 284 object. 286 4.3.5.1. Notification Format 288 All push notifications take the form of a standard StateChange object 289 (see Section 7.1 of [RFC8620]). 291 The specification extends the StateChange object with one additional 292 argument when used over a WebSocket: 294 o pushState: "String" (optional) 296 A (preferably short) string that encodes the entire server state 297 visible to the user (not just the objects returned in this call). 299 The purpose of the "pushState" token is to allow a client to 300 immediately get any changes that occurred while is was 301 disconnected (see Section 4.3.5.2). If the server does not 302 support "pushState" tokens, the client will have issue a series of 303 "/changes" requests (see Section 5.2 of [RFC8620]) upon 304 reconnection to update its state to match that of the server. 306 4.3.5.2. Enabling Notifications 308 A client enables push notifications from the server for the current 309 connection by sending a WebSocketPushEnable object to the server. A 310 WebSocketPushEnable object has the following properties: 312 o @type: "String" 314 This MUST be the string "WebSocketPushEnable". 316 o dataTypes: "String[]|null" 318 A list of data type names (e.g. "Mailbox", "Email") that the 319 client is interested in. A StateChange notification will only be 320 sent if the data for one of these types changes. Other types are 321 omitted from the TypeState object. If null, changes will be 322 pushed for all supported data types. 324 o pushState: "String" (optional) 326 The last "pushState" token that the client received from the 327 server. Upon receipt of a "pushState" token, the server SHOULD 328 immediately send all changes since that state token. 330 4.3.5.3. Disabling Notifications 332 A client disables push notifications from the server for the current 333 connection by sending a WebSocketPushDisable object to the server. A 334 WebSocketPushDisable object has the following property: 336 o @type: "String" 338 This MUST be the string "WebSocketPushDisable". 340 4.4. Examples 342 The following examples show WebSocket JMAP opening handshakes, a JMAP 343 Core/echo request and response, and a subsequent closing handshake. 344 The examples assume that the JMAP WebSocket URL endpoint has been 345 advertised in the JMAP Session object as having a path of "/jmap/ws/" 346 and that TLS negotiation has already succeeded. Note that folding of 347 header fields is for editorial purposes only. 349 WebSocket JMAP connection via HTTP/1.1 with push notifications for 350 mail [RFC8621] enabled. This example assumes that the client has 351 cached pushState "aaa" from a previous connection. 353 [[ From Client ]] [[ From Server ]] 355 GET /jmap/ws/ HTTP/1.1 356 Host: server.example.com 357 Upgrade: websocket 358 Connection: Upgrade 359 Authorization: Basic Zm9vOmJhcg== 360 Sec-WebSocket-Key: 361 dGhlIHNhbXBsZSBub25jZQ== 362 Sec-WebSocket-Protocol: jmap 363 Sec-WebSocket-Version: 13 364 Origin: https://www.example.com 366 HTTP/1.1 101 Switching Protocols 367 Upgrade: websocket 368 Connection: Upgrade 369 Sec-WebSocket-Accept: 370 s3pPLMBiTxaQ9kYGzzhZRbK+xOo= 371 Sec-WebSocket-Protocol: jmap 373 [WebSocket connection established] 375 WS_DATA 376 { 377 "@type": "WebSocketPushEnable", 378 "dataTypes": [ "Mailbox", "Email" ], 379 "pushState": "aaa" 380 } 382 WS_DATA 383 { 384 "@type": "StateChange", 385 "changed": { 386 "a456": { 387 "Mailbox": "d35ecb040aab" 388 } 389 }, 390 "pushState": "bbb" 391 } 393 WS_DATA 394 { 395 "@type": "Request", 396 "id": "R1", 397 "using": [ "urn:ietf:params:jmap:core" ], 398 "methodCalls": [ 399 [ 400 "Core/echo", { 401 "hello": true, 402 "high": 5 403 }, 404 "b3ff" 405 ] 406 ] 407 } 409 WS_DATA 410 { 411 "@type": "Response", 412 "requestId": "R1", 413 "methodResponses": [ 414 [ 415 "Core/echo", { 416 "hello": true, 417 "high": 5 418 }, 419 "b3ff" 420 ] 421 ] 422 } 424 WS_DATA 425 The quick brown fox jumps 426 over the lazy dog. 428 WS_DATA 429 { 430 "@type": "RequestError", 431 "requestId": null, 432 "type": 433 "urn:ietf:params:jmap:error:notJSON", 434 "status": 400, 435 "detail": 436 "The request did not parse as I-JSON." 437 } 439 [A new email is received] 441 WS_DATA 442 { 443 "@type": "StateChange", 444 "changed": { 445 "a123": { 446 "Email": "0af7a512ce70" 447 } 448 } 449 "pushState": "ccc" 450 } 452 WS_CLOSE 454 WS_CLOSE 456 [WebSocket connection closed] 457 WebSocket JMAP connection on a HTTP/2 stream which also negotiates 458 compression [RFC7692]: 460 [[ From Client ]] [[ From Server ]] 462 SETTINGS 463 SETTINGS_ENABLE_CONNECT_PROTOCOL = 1 465 HEADERS + END_HEADERS 466 :method = CONNECT 467 :protocol = websocket 468 :scheme = https 469 :path = /jmap/ws/ 470 :authority = server.example.com 471 origin: https://example.com 472 authorization = Basic Zm9vOmJhcg== 473 sec-websocket-protocol = jmap 474 sec-websocket-version = 13 475 sec-websocket-extensions = 476 permessage-deflate 477 origin = https://www.example.com 479 HEADERS + END_HEADERS 480 :status = 200 481 sec-websocket-protocol = jmap 482 sec-websocket-extensions = 483 permessage-deflate 485 [WebSocket connection established] 487 DATA 488 WS_DATA 489 [compressed text] 491 DATA 492 WS_DATA 493 [compressed text] 495 ... 497 DATA + END_STREAM 498 WS_CLOSE 500 DATA + END_STREAM 501 WS_CLOSE 503 [WebSocket connection closed] 504 [HTTP/2 stream closed] 506 5. Security Considerations 508 The security considerations for both WebSocket (see Section 10 of 509 [RFC6455]) and JMAP (see Section 8 of [RFC8620]) apply to the 510 WebSocket JMAP subprotocol. Specific security considerations are 511 described in subsections of this section. 513 5.1. Connection Confidentiality and Integrity 515 To ensure the confidentiality and integrity of data sent and received 516 via JMAP over WebSocket, the WebSocket connection MUST use TLS 1.2 517 [RFC5246] or later, following the recommendations in BCP 195 518 [RFC7525]. Servers SHOULD support TLS 1.3 [RFC8446] or later. 520 5.2. Non-Browser Clients 522 JMAP over WebSocket can be used by clients both running inside and 523 outside of a web browser. As such, the security considerations in 524 Sections 10.2 and 10.1 of [RFC6455] apply to those respective 525 environments. 527 6. IANA Considerations 529 6.1. Registration of the WebSocket JMAP Subprotocol 531 This specification requests IANA to register the WebSocket JMAP 532 subprotocol under the "WebSocket Subprotocol Name" Registry with the 533 following data: 535 Subprotocol Identifier: jmap 537 Subprotocol Common Name: WebSocket Transport for JMAP (JSON Meta 538 Application Protocol) 540 Subprotocol Definition: RFCXXXX (this document) 542 7. Acknowledgments 544 The author would like to thank the following individuals for 545 contributing their ideas and support for writing this specification: 546 Neil Jenkins, Robert Mueller, and Chris Newman. 548 8. References 549 8.1. Normative References 551 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 552 Requirement Levels", BCP 14, RFC 2119, 553 DOI 10.17487/RFC2119, March 1997, 554 . 556 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 557 DOI 10.17487/RFC2818, May 2000, 558 . 560 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 561 (TLS) Protocol Version 1.2", RFC 5246, 562 DOI 10.17487/RFC5246, August 2008, 563 . 565 [RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol", 566 RFC 6455, DOI 10.17487/RFC6455, December 2011, 567 . 569 [RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer 570 Protocol (HTTP/1.1): Authentication", RFC 7235, 571 DOI 10.17487/RFC7235, June 2014, 572 . 574 [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, 575 "Recommendations for Secure Use of Transport Layer 576 Security (TLS) and Datagram Transport Layer Security 577 (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May 578 2015, . 580 [RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext 581 Transfer Protocol Version 2 (HTTP/2)", RFC 7540, 582 DOI 10.17487/RFC7540, May 2015, 583 . 585 [RFC7692] Yoshino, T., "Compression Extensions for WebSocket", 586 RFC 7692, DOI 10.17487/RFC7692, December 2015, 587 . 589 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 590 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 591 May 2017, . 593 [RFC8441] McManus, P., "Bootstrapping WebSockets with HTTP/2", 594 RFC 8441, DOI 10.17487/RFC8441, September 2018, 595 . 597 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol 598 Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, 599 . 601 [RFC8620] Jenkins, N. and C. Newman, "The JSON Meta Application 602 Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July 603 2019, . 605 8.2. Informative References 607 [RFC8621] Jenkins, N. and C. Newman, "The JSON Meta Application 608 Protocol (JMAP) for Mail", RFC 8621, DOI 10.17487/RFC8621, 609 August 2019, . 611 Appendix A. Change History (To be removed by RFC Editor before 612 publication) 614 Changes since ietf-06: 616 o Removed open issue on security of WebSocket compression, per 617 Alexey Melnikov. 619 Changes since ietf-05: 621 o Renamed "webSocketUrl" to "url" and "supportsWebSocketPush" to 622 "supportsPush", per Benjamin Schwartz. 624 o Added a security subsection with a nod to Sections 10.1 and 10.2 625 of RFC6455, per Leif Johansson. 627 o Clarified "unsupported JMAP" vs "unsupported JSON", per Benjamin 628 Kaduk. 630 o Refer to RFC 7525 as BCP 195, per Benjamin Kaduk. 632 o Several editorial improvements from Benjamin Kaduk. 634 o Several editorial improvements from Murray Kucherawy. 636 Changes since ietf-04: 638 o Require the use of TLS for JMAP over WebSocket (per Alissa Cooper 639 and others). 641 o Added a section explaining how to handle unsupported messages (per 642 Bob Briscoe). 644 o Added a section specifically addressing authentication of the 645 WebSocket (per Leif Johansson). 647 o Corrected references into specific sections of RFC 8620 (per 648 Martin Vigoureax). 650 o Made RFC 7692 a normative reference (per Barry Leiba). 652 o Clarified that the "maxConcurrentRequests" limit applies to the 653 sum of all requests on the current connection (per Benjamin 654 Kaduk). 656 o Clarified that the "pushState" token represents the entire server 657 state visible to the user (per Banjamin Kaduk). 659 o Clarified that "WebSocketPushEnable/Disable" only effect the 660 current connection (per Benjamin Kaduk). 662 o Several editorial improvements from Benjamin Kaduk. 664 Changes since ietf-03: 666 o Updated JMAP Mail reference to RFC 8621. 668 o Specified that requestId MUST be present in a response if given in 669 the request. 671 Changes since ietf-02: 673 o Updated JMAP Core reference to RFC 8620. 675 o Added 'WebSocketPushDisable' object. 677 o Editorial and formatting changes. 679 Changes since ietf-01: 681 o Changed 'wsURL' to 'webSocketUrl' and removed push query option. 683 o Added 'supportsWebSocketPush' capability. 685 o Added '@type' argument to Request object. 687 o Added 'WebSocketPushEnable' object. 689 o Added 'pushState' argument to StateChange object. 691 o Updated example. 693 o Minor Editorial changes. 695 Changes since ietf-00: 697 o Added text describing advertisement of and selection of optional 698 push notifications. 700 o Minor Editorial changes. 702 Changes since murchison-02: 704 o Renamed as a JMAP WG document. 706 o Allow out of order processing. 708 o Allow push notifications. 710 o Modified examples. 712 o Add Security Considerations text. 714 o Minor Editorial changes. 716 Changes since murchison-01: 718 o Updated WebSocket over HTTP/2 reference to RFC8144. 720 Changes since murchison-00: 722 o Fleshed out section on discovery of support for JMAP over 723 WebSocket. 725 o Allow JSON Problem Details objects to be returned by the server 726 for toplevel errors. 728 o Mentioned the ability to compress JMAP API requests. 730 o Minor Editorial changes. 732 Author's Address 733 Kenneth Murchison 734 Fastmail US LLC 735 1429 Walnut Street - Suite 1201 736 Philadelphia, PA 19102 737 USA 739 Email: murch@fastmailteam.com 740 URI: http://www.fastmail.com/