JSON Meta Application Protocol (JMAP) Email Delivery Push Notifications
draft-jenkins-emailpush-00
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Author | Neil Jenkins | ||
| Last updated | 2024-11-14 | ||
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draft-jenkins-emailpush-00
JMAP N.M. Jenkins, Ed.
Internet-Draft Fastmail
Intended status: Standards Track 15 November 2024
Expires: 19 May 2025
JSON Meta Application Protocol (JMAP) Email Delivery Push Notifications
draft-jenkins-emailpush-00
Abstract
This document specifies an extension to the JSON Meta Application
Protocol (JMAP) that allows clients to receive an object via the JMAP
push channel whenever a new email is delivered that matches a client-
defined filter. The object can also include properties from the
email, to allow a user notification to be displayed without having to
make a further request.
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
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This Internet-Draft will expire on 19 May 2025.
Copyright Notice
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document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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provided without warranty as described in the Revised BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Addition to the Capabilities Object . . . . . . . . . . . . . 3
2.1. urn:ietf:params:jmap:emailpush . . . . . . . . . . . . . 3
3. The EmailDelivery object . . . . . . . . . . . . . . . . . . 4
4. Extension to the PushSubscription object . . . . . . . . . . 4
5. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7.1. JMAP Capability Registration for "emailpush" . . . . . . 8
8. Normative References . . . . . . . . . . . . . . . . . . . . 8
9. Informative References . . . . . . . . . . . . . . . . . . . 9
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The JSON Meta Application Protocol (JMAP) [RFC8620] defines a
mechanism for creating a push subscription, allowing a client to be
efficiently notified whenever the state on the server changes for a
data type the client is interested in. This can be used to trigger a
resync of that data in the client.
Many email clients wish to show the user a notification when a new
email arrives. Email clients implementing JMAP for Mail [RFC8621]
may subscribe to changes in the pseudo-type "EmailDelivery" to be
notified just whenever a new email is delivered to the store (as
opposed to whenever changes are made to the Email data in general,
which may be caused by user actions such as reading, organising, or
deleting their mail). However, this does not meet the needs of some
email clients in constrained environments, particularly on mobile:
1. Data is pushed for all email deliveries, but the client needs to
receive them only when a message arrives for which it intends to
show the user a notification. For example, this is commonly only
shown for messages delivered to the inbox by default, not
messages filtered to other mailboxes.
2. The client needs to make at least one HTTP request, and sometimes
more, to resynchronise its datastore before it can show a visible
notification to the user. This can sometimes fail when there is
poor connectivity. In such circumstances, the client is only
able to tell the user a new message has arrived, not any of the
details such as who sent it, or the subject.
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To address these issues, this document defines a way to receive a new
EmailDelivery object via the JMAP push subscription. Clients can
request a filter be applied to precisely restrict which messages they
are notified about. Clients may request certain properties of the
email sent in the EmailDelivery object, so it has sufficient
information to show the user a notification having to make any
further requests to the server.
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].
1.2. Terminology
The same terminology is used in this document as in the core JMAP
specification, see Section 1.6 of [RFC8620].
The term Email (with this specific capitalization) is used to refer
to the data type defined in Section 4 of [RFC8621].
2. Addition to the Capabilities Object
The capabilities object is returned as part of the JMAP Session
object; see Section 2 of [RFC8620]. This document defines an
additional capability URI.
2.1. urn:ietf:params:jmap:emailpush
The urn:ietf:params:jmap:emailpush capability support for the
extensions to PushSubscription described in this document. The value
of this property in the JMAP Session "capabilities" property is an
empty object.
Accounts for which email delivery push is supported MUST have this
capability in the account's "accountCapabilities" property. The
value is an empty object.
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Note, this capability may be supported in servers or accounts that do
not support the urn:ietf:params:jmap:mail capability — in such
servers, notification of new emails is supported but any further
interaction will require use of a different protocol, such as IMAP
[RFC9051].
3. The EmailDelivery object
An *EmailDelivery* object represents a new message that has been
delivered to the store. It has the following properties:
*@type*: String
This MUST be the string "EmailDelivery".
*accountId*: Id
The id of the Account this Email is in.
*email*: Email
An object with the properties of the Email object (as defined in
Section 4.1 of [RFC8621]) that were requested by the client in the
EmailDeliveryConfig. Note, push channels often have strict
restrictions on the size of data that can be sent. Properties
MUST be added to this object in the order defined in the
properties array of the associated EmailDeliveryConfig. If adding
a property would exceed the size limit for the push channel, the
property MUST be omitted. Clients are RECOMMENDED to only request
the properties they need for the visible notification, plus the
"id" property if they want to then fetch further information.
4. Extension to the PushSubscription object
The PushSubscription object is defined in Section 7.2 of [RFC8620].
This document defines an extra property for this object:
*emailDelivery*: Id[EmailDeliveryConfig]|null
If not null, this is a map. The keys are Account ids for accounts
with support for the urn:ietf:params:jmap:emailpush capability.
The server will push EmailDelivery objects for these accounts when
a new message arrives, in accordance with the associated
EmailDeliveryConfig options for the account.
An *EmailDeliveryConfig* object has the following properties:
*filter*: FilterOperator|FilterCondition|null
A filter to apply to determine which new messages to push an
EmailDelivery object for. The FilterCondition is as defined in
Section 4.4.1 of [RFC8621].
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If urn:ietf:params:jmap:mail capability is not supported for an
account, support for the "inMailbox" and "inMailboxOtherThan"
filter conditions is OPTIONAL. However, if the server supports
IMAP access to the same account with the ObjectID extension
[RFC8474], it MUST support using mailbox ids discovered via IMAP
with these filter conditions.
*properties*: String[]
The list of properties to include in the "email" value of the
EmailDelivery object. This is the same as the properties argument
in "Email/get", as defined in Section 4.2 of [RFC8621].
If urn:ietf:params:jmap:mail capability is supported the server
MUST support all the properties it supports for the "Email/get"
method. Otherwise, it MUST support the following properties:
* keywords
* from
* to
* cc
* subject
* preview
* receivedAt
* sentAt
If the server supports IMAP ObjectID [RFC8474], it MUST also
support the following properties:
* id
* threadId
* mailboxIds
5. Example
An email client connects to a server over IMAP ([RFC9051]) and after
authenticating, sees the OBJECTID [RFC8474] and JMAPACCESS
[I-D.ietf-extra-jmapaccess] capabilities advertised.
The JMAPACCESS IMAP capability gives it the URL for the JMAP session
resource, and guarantees the client can use the same credentials to
authenticate that it used for IMAP. The client fetches the JMAP
Session object and finds the following JMAP capabilities present:
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{
"urn:ietf:params:jmap:core": {
"maxCallsInRequest": 50,
"maxConcurrentUpload": 10,
"maxObjectsInGet": 4096,
"maxObjectsInSet": 4096,
"collationAlgorithms": [
"i;ascii-numeric",
"i;ascii-casemap",
"i;octet"
],
"maxSizeUpload": 250000000,
"maxSizeRequest": 10000000,
"maxConcurrentRequests": 10
},
"urn:ietf:params:jmap:emailpush": {},
}
Figure 1: The "capabilities" property of a JMAP Session object
The server doesn't support urn:ietf:params:jmap:mail yet, so the
client can't switch over to using JMAP fully instead of IMAP, but it
does support urn:ietf:params:jmap:emailpush, so the client can now
use JMAP to receive push notifications.
The user has asked the client to notify it of any message delivered
to the inbox, plus any message delivered to another folder that has
the $notify keyword set. The client discovers the mailbox id of the
inbox over IMAP using ObjectId, then creates a push subscription by
making the following API request:
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[[ "PushSubscription/set", {
"create": {
"4f29": {
"deviceClientId": "a889-ffea-910",
"url": "https://push.example.com/WmYD3enMWsSOE0ndiBZfYeg54j4eWHfI",
"keys": {
"p256dh": "BM0HH37xD8sEh8NeiHu1hFuwxqeeruxPlX5S7XGWGjHY5UT5yZFQKAiihFQLP6GuEQPQOtD9z28HRyV7e1nndh8",
"auth": "uwPFKACOLBipGPTVz4UCDg"
},
"types": [],
"emailDelivery": {
"A1412": {
"filter": {
"operator": "OR",
"conditions": [
{ "inMailbox": "674cc240-95db-49ce-a8a2-054f4f733095" },
{ "hasKeyword": "$notify" }
]
},
"properties": ["from", "subject", "id"]
}
}
}
}
}, "0" ]]
Figure 2: "methodCalls" Property of a JMAP Request
The server creates the push subscription and immediately pushes a
PushVerification object to the client. The client updates the
PushSubscription object with this value to validate it as per
Section 7.2.2 of [RFC8620]. With this done, the server will now push
an EmailDelivery object whenever a new message arrives that's
delivered to the mailbox with id "674cc240-95db-49ce-
a8a2-054f4f733095", or has the "$notify" keyword. As the "types"
property is the empty array, the server will not push any StateChange
objects. For example, a message arrives and the server pushes the
following:
{
"@type": "EmailDelivery",
"accountId": "A1412",
"email": {
"from": [{ "name": "John Smith", "email": "john@example.com" }],
"subject": "Surprise birthday party for Jane tonight",
"id": "M699bb151ca4cbf1c24364a68"
}
}
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Figure 3: An EmailDelivery object
6. Security Considerations
All security considerations of JMAP [RFC8620] apply to this
specification. Additional considerations are detailed below.
With the push defined in JMAP Core, no user data travels over the
push channel, only state strings. The EmailDelivery object on the
other hand contains sensitive user data. As specfied in Section 8.7
of [RFC8620], to ensure confidentiality and integrity of the user's
data, the client MUST specify encryption keys when establishing the
PushSubscription and ignore any push notification received that is
not encrypted with those keys.
7. IANA Considerations
7.1. JMAP Capability Registration for "emailpush"
IANA will register the "emailpush" JMAP Capability as follows:
Capability Name: urn:ietf:params:jmap:emailpush
Specification document: this document
Intended use: common
Change Controller: IETF
Security and privacy considerations: this document, Section 6
8. 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>.
[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>.
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[I-D.ietf-extra-jmapaccess]
Gulbrandsen, A. and B. Gondwana, "The JMAPACCESS Extension
for IMAP", Work in Progress, Internet-Draft, draft-ietf-
extra-jmapaccess-09, 15 May 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-extra-
jmapaccess-09>.
9. Informative References
[RFC8474] Gondwana, B., Ed., "IMAP Extension for Object
Identifiers", RFC 8474, DOI 10.17487/RFC8474, September
2018, <https://www.rfc-editor.org/info/rfc8474>.
[RFC9051] Melnikov, A., Ed. and B. Leiba, Ed., "Internet Message
Access Protocol (IMAP) - Version 4rev2", RFC 9051,
DOI 10.17487/RFC9051, August 2021,
<https://www.rfc-editor.org/info/rfc9051>.
Author's Address
Neil Jenkins (editor)
Fastmail
PO Box 234, Collins St West
Melbourne VIC 8007
Australia
Email: neilj@fastmailteam.com
URI: https://www.fastmail.com
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