JMAP for Quotas
draft-ietf-jmap-quotas-06

JMAP                                                   R.C. Cordier, Ed.
Internet-Draft                                          Linagora Vietnam
Intended status: Standards Track                       28 September 2022
Expires: 1 April 2023

                            JMAP for Quotas
                       draft-ietf-jmap-quotas-06

Abstract

   This document specifies a data model for handling quotas on accounts
   with a server using JMAP.

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   This Internet-Draft will expire on 1 April 2023.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2

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     1.1.  Notational conventions  . . . . . . . . . . . . . . . . .   2
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.3.  Addition to the capabilities object . . . . . . . . . . .   3
       1.3.1.  urn:ietf:params:jmap:quota  . . . . . . . . . . . . .   3
     1.4.  Data types  . . . . . . . . . . . . . . . . . . . . . . .   3
       1.4.1.  Scope . . . . . . . . . . . . . . . . . . . . . . . .   3
       1.4.2.  ResourceType  . . . . . . . . . . . . . . . . . . . .   4
     1.5.  Push  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Quota . . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Quota/get . . . . . . . . . . . . . . . . . . . . . . . .   5
     2.2.  Quota/changes . . . . . . . . . . . . . . . . . . . . . .   5
     2.3.  Quota/query . . . . . . . . . . . . . . . . . . . . . . .   6
     2.4.  Quota/queryChanges  . . . . . . . . . . . . . . . . . . .   6
     2.5.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .   6
       2.5.1.  Fetching quotas . . . . . . . . . . . . . . . . . . .   7
       2.5.2.  Requesting latest quota changes . . . . . . . . . . .   7
   3.  Security considerations . . . . . . . . . . . . . . . . . . .   8
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     4.1.  JMAP Capability Registration for "quota"  . . . . . . . .   9
   5.  Normative References  . . . . . . . . . . . . . . . . . . . .   9
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

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

   This specification defines a data model for handling quotas over
   JMAP, allowing you to read and explain quota information.

   This specification does not address quota administration, which
   should be handled by other means.

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.

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   Servers MUST support all properties specified for the new data types
   defined in this document.

1.2.  Terminology

   The same terminology is used in this document as in the core JMAP
   specification.

   The term Quota (with that specific capitalization) is used to refer
   to the data type defined in this document and instance of that data
   type.

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:quota

   This represents support for the Quota data type and associated API
   methods.  Servers supporting this specification MUST add a property
   called urn:ietf:params:jmap:quota to the capabilities object.

   The value of this property is an empty object in both the JMAP
   session capabilities property and an account's accountCapabilities
   property.

1.4.  Data types

   In addition to the standard JSON data types, a couple of additional
   data types are common to the definition of Quota objects and
   properties.

1.4.1.  Scope

   The *Scope* is a String from an enumeration defined list of values,
   handled by the server.

   It explains the entities this value applies to.  Values for the
   *Scope* are:

   *  account: Applies for this account

   *  domain: All accounts of this domain share this part of the quota

   *  global: All accounts of this server share this part of the quota

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1.4.2.  ResourceType

   The *ResourceType* is a String from an enumeration defined list of
   values, handled by the server.

   A resource type is like an unit of measure for the quota usage.
   Values for the *ResourceType* are:

   *  count: The quota is measured in number of data type objects.  For
      example, a quota can have a limit of 50 Mail objects.

   *  octets: The quota is measured in size (in octets).  For example, a
      quota can have a limit of 25000 octets.

1.5.  Push

   Servers MUST support the JMAP push mechanisms, as specified in
   [RFC8620] Section 7, to receive notifications when the state changes
   for the Quota type defined in this specification.

2.  Quota

   The quota is an object that displays the limit set to an account
   usage as well as the current usage in regard to that limit.

   The quota object MUST contain the following fields:

   *  *id*: Id The unique identifier for this object.  It should respect
      the JMAP ID datatype defined in section 1.2 of [RFC8620]

   *  *resourceType*: ResourceType The resource type of the quota.

   *  *used*: UnsignedInt The current usage of the defined quota.
      Computation of this value is handled by the server.

   *  *limit*: UnsignedInt The hard limit set by this quota.  Objects in
      scope may not be created or updated if we reach this limit.  It
      should be higher than the warnLimit and the softLimit.

   *  *scope*: Scope The Scope of this quota.

   *  *name*: String The name of the quota object.  Useful for managing
      quotas and use queries for searching.

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   *  *datatypes*: String[] A list of all the data types values that are
      applying to this quota.  This allows to assign quotas to separated
      or shared data types.  This MAY include data types the client does
      not recognise.  Clients MUST ignore any unknown data type in the
      list.

   The quota object MAY contain the following field:

   *  *warnLimit*: UnsignedInt|null The warn limit set by this quota
      object.  It can be used to send a warning to an entity about to
      reach the hard limit soon, but with no action taken yet.  If set,
      it should be lower than the softLimit and the limit.

   *  *softLimit*: UnsignedInt|null The soft limit set by this quota
      object.  It can be used to still allow some operations, but
      refusing some others.  What is allowed or not is up to the server.
      For example, it could be used for blocking outgoing events of an
      entity (sending emails, creating calendar events, ...) while still
      receiving incoming events (receiving emails, receiving calendars
      events, ...).  If set, it should be higher than the warnLimit but
      lower than the limit.

   *  *description*: String|null Arbitrary free, human readable,
      description of this quota.  Might be used to explain where the
      limit comes from and explain the entities and data types this
      quota applies to.

2.1.  Quota/get

   Standard "/get" method as described in [RFC8620] section 5.1.  The
   ids argument may be null to fetch all at once.

2.2.  Quota/changes

   Standard "/changes" method as described in [RFC8620] section 5.2 but
   with one extra argument to the response:

   *  *updatedProperties*: String[]|null If only the "used" Quota
      properties has changed since the old state, this will be the list
      of properties that may have changed.  If the server is unable to
      tell if only "used" has changed, it MUST just be null.

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   Since "used" frequently changes but other properties are generally
   only changed rarely, the server can help the client optimise data
   transfer by keeping track of changes to Quota usage separate from
   other state changes.  The updatedProperties array may be used
   directly via a back-reference in a subsequent Quota/get call in the
   same request, so only these properties are returned if nothing else
   has changed.

   Servers MAY decide to add other properties to the list that they
   judge changing frequently.

2.3.  Quota/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:

   *  *name*: String The Quota _name_ property contains the given
      string.

   *  *scopes*: Scope[] The Quota _scope_ property must be in this list
      to match the condition.

   *  *resourceTypes*: ResourceType[] The Quota _resourceType_ property
      must be in this list to match the condition.

   *  *datatypes*: String[] The Quota _datatypes_ property must contain
      the elements in this list to match the condition.

   A Quota object matches the FilterCondition if and only if all of the
   given conditions match.  If zero properties are specified, it is
   automatically true for all objects.

   The following Quota properties MUST be supported for sorting:

   *  *name*

   *  *used*

2.4.  Quota/queryChanges

   This is a standard "/queryChanges" method as described in [RFC8620],
   Section 5.6.

2.5.  Examples

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2.5.1.  Fetching quotas

   Request fetching all quotas related to an account :

                        [[ "Quota/get", {
                          "accountId": "u33084183",
                          "ids": null
                        }, "0" ]]

   With response :

            [[ "Quota/get", {
              "accountId": "u33084183",
              "state": "78540",
              "list": [{
                "id": "2a06df0d-9865-4e74-a92f-74dcc814270e",
                "resourceType": "count",
                "used": 1056,
                "warnLimit": 1600,
                "softLimit": 1800,
                "limit": 2000,
                "scope": "account",
                "name": "bob@example.com",
                "description": "Personal account usage",
                "datatypes" : [ "Mail", "Calendar", "Contact" ]
              }, {
                "id": "3b06df0e-3761-4s74-a92f-74dcc963501x",
                "resourceType": "octets",
                ...
              }, ...],
              "notFound": []
            }, "0" ]]

2.5.2.  Requesting latest quota changes

   Request fetching the changes for a specific quota:

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                     [[ "Quota/changes", {
                       "accountId": "u33084183",
                       "sinceState": "10824",
                       "maxChanges": 20,
                       "updatedProperties": ["used"]
                     }, "0" ],
                     [ "Quota/get", {
                       "accountId": "u33084183",
                       "#ids": {
                         "resultOf": "0",
                         "name": "Quota/changes",
                         "path": "/updated"
                       },
                       "#properties": {
                         "resultOf": "0",
                         "name": "Quota/changes",
                         "path": "/updatedProperties"
                       }
                     }, "1" ]]

   With response:

          [[ "Quota/changes", {
            "accountId": "u33084183",
            "oldState": "10824",
            "newState": "10826",
            "hasMoreChanges": false,
            "created": [],
            "updated": ["2a06df0d-9865-4e74-a92f-74dcc814270e"],
            "destroyed": []
          }, "0" ],
          [ "Quota/get", {
            "accountId": "u33084183",
            "state": "10826",
            "list": [{
              "id": "2a06df0d-9865-4e74-a92f-74dcc814270e",
              "used": 1246
            }],
            "notFound": []
          }, "1" ]]

3.  Security considerations

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

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   Implementors should be careful to make sure the implementation of
   that extension does not violate the site's security policy.  The
   resource usage of other users is likely to be considered confidential
   information and should not be divulged to unauthorized persons.

   As for any resource shared across users (for example, a quota with
   the domain or global scope), a user that can consume the resource can
   affect the resources available to the other users.  For example, a
   user could spam himself with events and make the shared resource hit
   the limit and unusable for others (implementors could mitigate that
   with some rate limiting implementation on the server).

4.  IANA Considerations

4.1.  JMAP Capability Registration for "quota"

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

   Capability Name: urn:ietf:params:jmap:quota

   Specification document: this document

   Intended use: common

   Change Controller: IETF

   Security and privacy considerations: this document, section 4.

5.  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>.

   [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>.

   [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>.

Author's Address

   René Cordier (editor)
   Linagora Vietnam
   5 Dien Bien Phu

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   Hanoi
   10000
   Vietnam
   Email: rcordier@linagora.com
   URI:   https://linagora.vn

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