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Versions: (draft-murchison-jmap-sieve) 00 01 02

JMAP                                                        K. Murchison
Internet-Draft                                                  Fastmail
Intended status: Standards Track                       September 4, 2020
Expires: March 8, 2021


                         JMAP for Sieve Scripts
                        draft-ietf-jmap-sieve-00

Abstract

   This document specifies a data model for managing Sieve scripts on a
   server using JMAP.

Open Issues

   o  Do we need/want both "content" and "blobId" in the SieveScript
      object?  It may be simpler to have just one way of specifying
      content and "blobId" is more versatile and doesn't require JSON-
      encoding of the content.  Furthermore, use of the forthcoming(?)
      Blob/set method would avoid the extra roundtrip of having to
      upload the blob first.

   o  Should changes made by onSuccessActivateScript be reported in the
      response to the client-initiated request, or via a second implicit
      SIeveScript/set response?

   o  The strawman for SieveScript/test only uses blobIds.  Will this
      have to change once the issue regarding content/blobId in
      SieveScript is resolved?

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 8, 2021.




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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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Notational Conventions  . . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.3.  Addition to the Capabilities Object . . . . . . . . . . .   3
       1.3.1.  urn:ietf:params:jmap:sieve  . . . . . . . . . . . . .   3
   2.  Sieve Scripts . . . . . . . . . . . . . . . . . . . . . . . .   5
     2.1.  SieveScript/get . . . . . . . . . . . . . . . . . . . . .   6
     2.2.  SieveScript/set . . . . . . . . . . . . . . . . . . . . .   6
     2.3.  SieveScript/query . . . . . . . . . . . . . . . . . . . .   8
     2.4.  SieveScript/validate  . . . . . . . . . . . . . . . . . .   9
     2.5.  SieveScript/test  . . . . . . . . . . . . . . . . . . . .  10
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
     4.1.  JMAP Capability Registration for "sieve"  . . . . . . . .  11
     4.2.  JMAP Error Codes Registry . . . . . . . . . . . . . . . .  12
       4.2.1.  scriptNameExists  . . . . . . . . . . . . . . . . . .  12
       4.2.2.  tooManyScripts  . . . . . . . . . . . . . . . . . . .  12
       4.2.3.  invalidScript . . . . . . . . . . . . . . . . . . . .  12
       4.2.4.  scriptIsActive  . . . . . . . . . . . . . . . . . . .  13
   5.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  13
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  13
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Appendix A.  Change History (To be removed by RFC Editor before
                publication) . . . . . . . . . . . . . . . . . . . .  15
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  15








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1.  Introduction

   JMAP ([RFC8620] - JSON Meta Application Protocol) is a generic
   protocol for synchronizing data, such as mail, calendars or contacts,
   between a client and a server.  It is optimized for mobile and web
   environments, and aims to provide a consistent interface to different
   data types.

   This specification defines a data model for managing Sieve [RFC5228]
   scripts on a server using JMAP.  The data model is designed to allow
   a server to provide consistent access to the same scripts via
   ManageSieve [RFC5804] as well as JMAP, however the functionality
   offered over the two protocols may differ.

1.1.  Notational Conventions

   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.

   Type signatures, examples, and property descriptions in this document
   follow the conventions established in Section 1.1 of [RFC8620].  Data
   types defined in the core specification are also used in this
   document.

1.2.  Terminology

   The same terminology is used in this document as in the core JMAP
   specification, see [RFC8620], Section 1.6.

   The term SieveScript (with this specific capitalization) is used to
   refer to the data type defined in this document and instances of
   those data types.

1.3.  Addition to the Capabilities Object

   The capabilities object is returned as part of the JMAP Session
   object; see [RFC8620], Section 2.  This document defines one
   additional capability URI.

1.3.1.  urn:ietf:params:jmap:sieve

   This represents support for the SieveScript data type and associated
   API methods.  The value of this property in the JMAP Session
   capabilities property is an empty object.




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   The value of this property in an account's accountCapabilities
   property is an object that MUST contain the following information on
   server capabilities:

   o  *supportsTest*: "Boolean"

      If true, the server supports the SieveScript/test (Section 2.5)
      method.



   o  *maxNumberRedirects*: "UnsignedInt|null"

      The maximum number of Sieve "redirect" actions a script can
      perform during a single evaluation (see [RFC5804], Section 1.7),
      or "null" for no limit.



   o  *maxNumberScripts*: "UnsignedInt|null"

      The maximum number of Sieve scripts the server is willing to store
      for the user, or "null" for no limit.



   o  *maxSizeScript*: "UnsignedInt|null"

      The maximum size (in octets) of a Sieve script the server is
      willing to store for the user, or "null" for no limit.



   o  *sieveExtensions*: "String[]"

      A list of case-sensitive Sieve capability strings (as listed in
      Sieve "require" action [RFC5228], Section 3.2) indicating the
      extensions supported by the Sieve engine.



   o  *notificationMethods*: "String[]|null"

      A list of URI schema parts [RFC3986] for notification methods
      supported by the Sieve "enotify" extension [RFC5435], or "null" if
      the extension is not supported by the Sieve engine.





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   o  *externalLists*: "String[]|null"

      A list of URI schema parts [RFC3986] for externally stored list
      types supported by the Sieve "extlists" extension [RFC6134], or
      "null" if the extension is not supported by the Sieve engine.

2.  Sieve Scripts

   A *SieveScript* object represents a single Sieve [RFC5228] script.  A
   user may have multiple SieveScripts on the server, yet only one
   script may be used for filtering of incoming messages.  This is the
   active script.  Users may have zero or one active script.  The
   SieveScript/set (Section 2.2) method described below is used for
   changing the active script or disabling Sieve processing.

   A *SieveScript* object has the following properties:

   o  *id*: "Id" (immutable; server-set)

      The id of the script.



   o  *name*: "String"

      The unique user-visible name for the script, subject to the
      requirements in [RFC5804], Section 1.6.



   o  *content*: "String"

      The raw octets of the script [RFC5228].

      Note that both Sieve and JSON require encoding of special
      characters which MUST be done in the following order:

      1.  Escape any double quote (") or backslash (\) characters
          appearing inside of quoted strings in the Sieve code per
          Section 2.4.2 of [RFC5228].  E.g., A string containing the
          value \foo becomes "\\foo".

      2.  Escape any double quote ("), backslash (\), tab, carriage
          return, or line feed characters appearing in the resultant
          Sieve code per Section 7 of [RFC8259].  E.g., The example
          string in step 1 becomes \"\\\\foo\".

   o  *blobId*: "Id" (immutable)



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      The id of the blob containing the raw octets of the script
      [RFC5228].



   o  *isActive*: "Boolean" (server-set; default: false)

      Is this the user's active script?



   Example (using the Imap4Flags [RFC5232] Extension):

   {
     "id": "665c423a-6991-4733-8c7c-52b299572c66",
     "name": "example.siv",
     "content":
        "require [ \"imap4flags\" ];\r\nkeep :flags \"\\\\flagged\";",
     "isActive": false
   }

2.1.  SieveScript/get

   This is a standard "/get" method as described in [RFC8620],
   Section 5.1.  The _ids_ argument may be "null" to fetch all at once.

   This method provides similar functionality to the GETSCRIPT and
   LISTSCRIPTS commands in [RFC5804].

2.2.  SieveScript/set

   This is a standard "/set" method as described in [RFC8620],
   Section 5.3 but with the following additional request arguments,
   either of which may be omitted:

   o  *replaceOnCreate*: "Boolean" (default: false)

      If false, any attempt to create a SieveScript having the same
      "name" property as an existing SieveScript MUST be rejected with a
      "scriptNameExists" SetError.  If true, the existing SieveScript
      will be destroyed and the new SieveScript created as a single
      atomic action.  The id of the replaced SieveScript MUST be
      reported in the "destroyed" argument in the response.



   o  *onSuccessActivateScript*: "Id|null"




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      The id of the SieveScript to activate if the create/update/destroy
      succeeds.  (For references to SieveScript creations, this is
      equivalent to a creation-reference, so the id will be the creation
      id prefixed with a "#".)  If "null", the currently active script
      (if any) will be deactivated.  If this argument is not present in
      the request, the currently active script (if any) will remain as
      such.



   This method provides similar functionality to the PUTSCRIPT,
   DELETESCRIPT, RENAMESCRIPT, and SETACTIVE commands in [RFC5804].

   When creating or updating a script, a client MUST include either a
   _content_ or a _blobId_ property.  A request that includes neither or
   both properties MUST be rejected with an "invalidProperties"
   SetError.  The server MUST check the script content for syntactic
   validity, which includes checking that all Sieve extensions mentioned
   in Sieve script "require" statement(s) are supported by the Sieve
   interpreter.  (Note that if the Sieve interpreter supports the Sieve
   "ihave" extension [RFC5463], any unrecognized/unsupported extension
   mentioned in the "ihave" test MUST NOT cause the syntactic validation
   failure.)  A script of zero length SHOULD be considered invalid.  If
   the script content is invalid the request MUST be rejected with a
   "invalidScript" SetError.

   Note that simply activating or deactivating a script without changing
   any script content is accomplished via a request containing an
   "onSuccessActivateScript" argument and "null" "create", "update", and
   "delete" arguments.

   The following extra SetError types are defined:

   For "create":

   o  *scriptNameExists*:

      A SieveScript already exists with the given *name* property, and
      the "replaceOnCreate" argument was false.  An _existingId_
      property of type _Id_ MUST be included on the SetError object with
      the id of the existing SieveScript.



   o  *tooManyScripts*:

      Creating the SieveScript would exceed the *maxNumberScripts* limit
      (see Section 1.3.1).



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   For "create" and "update":

   o  *invalidScript*:

      The SieveScript violates the Sieve grammar [RFC5228] and/or one or
      more extensions mentioned in the script's "require" statement(s)
      are not supported by the Sieve interpreter.  The _description_
      property on the SetError object SHOULD contain a specific error
      message giving the line number of the first error.



   For "destroy":

   o  *scriptIsActive*:

      The SieveScript is active and the "onSuccessActivateScript"
      argument was not present.



2.3.  SieveScript/query

   This is a standard "/query" method as described in [RFC8620],
   Section 5.5.  A _FilterCondition_ object has the following
   properties, any of which may be omitted:

   o  *name*: "String"

      The SieveScript "name" property contains the given string.



   o  *isActive*: "Boolean"

      The "isActive" property of the SieveScript must be identical to
      the value given to match the condition.



   The following SieveScript properties MUST be supported for sorting:

   o  "name"

   o  "isActive"






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2.4.  SieveScript/validate

   This method is used by the client to verify Sieve script validity
   without storing the script on the server.

   The method provides similar functionality to the CHECKSCRIPT command
   in [RFC5804].

   The *SieveScript/validate* method takes the following arguments:

   o  *accountId*: "Id"

      The id of the account to use.



   o  *content*: "String"

      The raw octets of the script [RFC5228].



   o  *blobId*: "Id" (immutable)

      The id of the blob containing the raw octets of the script
      [RFC5228].



   A client MUST include either a _content_ or a _blobId_ property.  A
   request that includes neither or both properties MUST be rejected
   with an "invalidProperties" SetError.  The _content_ property, if
   used, MUST be encoded following the same procedure as for the
   _content_ property in the SieveScript (Section 2) object.  The server
   MUST check the script content for syntactic validity, which includes
   checking that all Sieve extensions mentioned in Sieve script
   "require" statement(s) are supported by the Sieve interpreter.  (Note
   that if the Sieve interpreter supports the Sieve "ihave" extension
   [RFC5463], any unrecognized/unsupported extension mentioned in the
   "ihave" test MUST NOT cause the syntactic validation failure.)

   The response has the following arguments:

   o  *accountId*: "Id"

      The id of the account used for this call.





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   o  *error*: "SetError|null"

      A SetError object if the request or the script content invalid, or
      "null" if the script content is valid.



2.5.  SieveScript/test

   This method is used by the client to ask the Sieve interpreter to
   evaluate a Sieve script against a given email and report what actions
   would be performed.

   The *SieveScript/test* method takes the following arguments:

   o  *accountId*: "Id"

      The id of the account to use.



   o  *scriptId*: "Id"

      The id of the SieveScript to test against.



   o  *emailId*: "Id"

      The id of the Email [RFC8621] to test against.



   o  *envelope*: "Envelope|null"

      Information that the Sieve interpreter should assume was present
      in the SMTP transaction that delivered the email when evaluating
      "envelope" tests.  If "null", all "envelope" tests MUST eveluate
      to false.  See Section 7 of Email [RFC8621] for the contents of
      the Envelope object.



   o  *lastVacationResponse*: "Date|null"

      The date-time at which the Sieve interpreter should assume that it
      last auto-replied to the sender of the email, or "null" if the




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      Sieve interpreter should assume that it has not auto-replied to
      the sender.



   The response has the following arguments:

   o  *accountId*: "Id"

      The id of the account used for this call.



   o  *actions*: "String[]|null"

      A set of strings listing the actions that would be performed, or
      "null" if evaluation of the script failed for any reason.



   o  *error*: "SetError|null"

      A SetError object if the request, the SieveScript, or the Email is
      invalid, or if the Sieve interpreter experienced a run-time error.
      Otherwise, "null" indicates that the script evalution completed
      successfully.  A "serverFail" SetError (see Section 3.6.2 of
      [RFC8620]) MUST be used to indicate a Sieve interpreter run-time
      error.



3.  Security Considerations

   All security considerations of JMAP [RFC8620] apply to this
   specification.

4.  IANA Considerations

4.1.  JMAP Capability Registration for "sieve"

   IANA will register the "sieve" JMAP Capability as follows:

   Capability Name: "urn:ietf:params:jmap:sieve"

   Specification document: this document

   Intended use: common




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   Change Controller: IETF

   Security and privacy considerations: this document, Section 3

4.2.  JMAP Error Codes Registry

   The following sub-section register several new error codes in the
   JMAP Error Codes registry, as defined in [RFC8620].

4.2.1.  scriptNameExists

   JMAP Error Code: scriptNameExists

   Intended use: common

   Change controller: IETF

   Reference: This document, Section 2.2

   Description: The client tried to create a SieveScript with the same
   "name" property as an existing SieveScript and the "replaceOnCreate"
   argument was false.  present.

4.2.2.  tooManyScripts

   JMAP Error Code: tooManyScripts

   Intended use: common

   Change controller: IETF

   Reference: This document, Section 2.2

   Description: Creating the SieveScript would exceed the
   "maxNumberScripts" limit.

4.2.3.  invalidScript

   JMAP Error Code: invalidScript

   Intended use: common

   Change controller: IETF

   Reference: This document, Section 2.2






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   Description: The SieveScript violates the Sieve grammar [RFC5228]
   and/or one or more extensions mentioned in the script's "require"
   statement(s) are not supported by the Sieve interpreter.

4.2.4.  scriptIsActive

   JMAP Error Code: scriptIsActive

   Intended use: common

   Change controller: IETF

   Reference: This document, Section 2.2

   Description: The client tried to destroy the active SieveScript, but
   the "OnSuccessActivateScript" argument was not present.

5.  Acknowledgments

   The concepts in this document are based largely on those in
   [RFC5804].  The author would like to thank the authors of that
   document for providing both inspiration and some borrowed text for
   this document.

   The author would also like to thank the following individuals for
   contributing their ideas and support for writing this specification:
   Bron Gondwana, Alexey Melnikov, and Ricardo Signes.

6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC5228]  Guenther, P., Ed. and T. Showalter, Ed., "Sieve: An Email
              Filtering Language", RFC 5228, DOI 10.17487/RFC5228,
              January 2008, <https://www.rfc-editor.org/info/rfc5228>.






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   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              DOI 10.17487/RFC5322, October 2008,
              <https://www.rfc-editor.org/info/rfc5322>.

   [RFC5435]  Melnikov, A., Ed., Leiba, B., Ed., Segmuller, W., and T.
              Martin, "Sieve Email Filtering: Extension for
              Notifications", RFC 5435, DOI 10.17487/RFC5435, January
              2009, <https://www.rfc-editor.org/info/rfc5435>.

   [RFC5804]  Melnikov, A., Ed. and T. Martin, "A Protocol for Remotely
              Managing Sieve Scripts", RFC 5804, DOI 10.17487/RFC5804,
              July 2010, <https://www.rfc-editor.org/info/rfc5804>.

   [RFC6134]  Melnikov, A. and B. Leiba, "Sieve Extension: Externally
              Stored Lists", RFC 6134, DOI 10.17487/RFC6134, July 2011,
              <https://www.rfc-editor.org/info/rfc6134>.

   [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>.

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/info/rfc8259>.

   [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>.

   [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>.

6.2.  Informative References

   [RFC5232]  Melnikov, A., "Sieve Email Filtering: Imap4flags
              Extension", RFC 5232, DOI 10.17487/RFC5232, January 2008,
              <https://www.rfc-editor.org/info/rfc5232>.

   [RFC5463]  Freed, N., "Sieve Email Filtering: Ihave Extension",
              RFC 5463, DOI 10.17487/RFC5463, March 2009,
              <https://www.rfc-editor.org/info/rfc5463>.








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Appendix A.  Change History (To be removed by RFC Editor before
             publication)

   Changes since murchison-01:

   o  Explicitly stated that Sieve capability strings are case-
      sensitive.

   o  errorDescription is now String|null.

   o  Added /query method.

   o  Added /test method.

   Changes since murchison-00:

   o  Added IANA registration for "scriptIsActive" JMAP error code.

   o  Added open issue about /set{create} with an existing script name.

Author's Address

   Kenneth Murchison
   Fastmail US LLC
   1429 Walnut Street - Suite 1201
   Philadelphia, PA  19102
   USA

   Email: murch@fastmailteam.com






















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