This JEP specifies recommended best practices for remote controlling clients using Ad-Hoc Commands.
NOTICE: This JEP is currently within Last Call or under consideration by the Jabber Council for advancement to the next stage in the JSF standards process. For further details, visit <http://www.jabber.org/council/queue.shtml>.
Status: Proposed
Type: Informational
Number: 0146
Version: 0.3
Last Updated: 2006-01-25
JIG: Standards JIG
Approving Body: Jabber Council
Dependencies: XMPP Core, JEP-0050
Supersedes: None
Superseded By: None
Short Name: N/A
Wiki Page: <http://wiki.jabber.org/index.php/Remote Controlling Clients (JEP-0146)>
Email:
remko@el-tramo.be
JID:
remko@fab4.be
Email:
stpeter@jabber.org
JID:
stpeter@jabber.org
This Jabber Enhancement Proposal is copyright 1999 - 2006 by the Jabber Software Foundation (JSF) and is in full conformance with the JSF's Intellectual Property Rights Policy <http://www.jabber.org/jsf/ipr-policy.shtml>. This material may be distributed only subject to the terms and conditions set forth in the Creative Commons Attribution License (<http://creativecommons.org/licenses/by/2.5/>).
The preferred venue for discussion of this document is the Standards-JIG discussion list: <http://mail.jabber.org/mailman/listinfo/standards-jig>.
The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 3920) and XMPP IM (RFC 3921) specifications contributed by the Jabber Software Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this JEP has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.
The keywords "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 RFC 2119.
When one has multiple clients at different locations logged in simultaneously, it is often desirable to control these clients from the client you are currently using. There are a number of common tasks one might want to perform remotely on clients: change the status of the client, forward all received unread messages to this client, and so on. Therefore, it makes sense to define a protocol for performing these tasks.
This JEP describes a protocol to perform a set of common tasks on a remote client, by specifying a profile of Ad-Hoc Commands [1].
This JEP addresses the following requirements:
A client MUST advertise any remote controlling commands it supports via Service Discovery [2] (as described in JEP-0050: Ad-Hoc Commands). Entity Capabilities [3] can be used to query capability of remote controlling commands in a client.
This JEP defines a profile of JEP-0050: Ad-Hoc Commands that enables a user to perform the following tasks on a remote client:
Although this JEP aims to define common use cases for remote controlling clients, an implementation or deployment MAY support any subset and MAY support additional commands not defined herein.
Note: The text that follows assumes that implementors have read and understood JEP-0050: Ad-Hoc Commands.
It is common to forget changing the status of a resource when leaving the client for a longer period. When realizing this while at another location, it might be desirable to change the status from there, to avoid contacts thinking that resource is attended and sending it messages.
Example 1. Local Client Requests to Set the Status of a Remote Client
<iq from='juliet@example.com/chamber'
to='juliet@example.com/balcony'
type='set'
id='set-status-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
action='execute'
node='http://jabber.org/protocol/rc#set-status'/>
</iq>
Unless an error occurs (see the Error Handling section below), the service SHOULD return the appropriate form.
Example 2. Remote Client Replies with a Form to Set its Status
<iq from='juliet@example.com/balcony'
to='juliet@example.com/chamber'
type='result'
id='set-status-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#set-status'
sessionid='set-status:20040727T0337Z'
status='executing'>
<x xmlns='jabber:x:data' type='form'>
<title>Change Status</title>
<instructions>Choose the status and status message</instructions>
<field type='hidden' var='FORM_TYPE'>
<value>http://jabber.org/protocol/rc</value>
</field>
<field label='Status'
type='list-single'
var='status'>
<required/>
<value>online</value>
<option label='Chat'>
<value>chat</value>
</option>
<option label='Online'>
<value>online</value>
</option>
<option label='Away'>
<value>away</value>
</option>
<option label='Extended Away'>
<value>xa</value>
</option>
<option label='Do Not Disturb'>
<value>dnd</value>
</option>
<option label='Invisible'>
<value>invisible</value>
</option>
<option label='Offline'>
<value>offline</value>
</option>
</field>
<field label='Priority'
type='text-single'
var='status-priority'>
<value>5</value>
</field>
<field label='Message'
type='text-multi'
var='status-message'/>
</x>
</command>
</iq>
Example 3. Local Client Submits Set Status Form to Remote Client
<iq from='juliet@example.com/chamber'
to='juliet@example.com/balcony'
type='set'
id='set-status-2'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#set-status'
sessionid='set-status:20040727T0337Z'>
<x xmlns='jabber:x:data' type='form'>
<field type='hidden' var='FORM_TYPE'>
<value>http://jabber.org/protocol/rc</value>
</field>
<field type='list-single' var='status'>
<value>xa</value>
</field>
<field type='text-single' var='status-priority'>
<value>-1</value>
</field>
<field type='text-multi' var='status-message'>
<value>In my chamber.</value>
</field>
</x>
</command>
</iq>
If the 'status-priority' variable is omitted, the client SHOULD NOT change the priority of the client
Example 4. Remote Client Informs Local Client of Completion
<iq from='juliet@example.com/balcony'
to='juliet@example.com/chamber'
type='result'
id='set-status-2'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#set-status'
sessionid='set-status:20040727T0337Z'
status='completed'/>
</iq>
Notification of completion MAY include the processed data in a data form of type 'result'.
A user might want to forward all the unread messages residing at the remote client to the local client (e.g. when the remote client was accidentally left on-line, and has received messages in the meantime).
For example, suppose Romeo sends a message to Juliet, thinking she is still on her balcony. The balcony client receives the message:Example 5. Remote Client Receives Message
<message from='romeo@example.com/orchard'
to='juliet@example.com/balcony'>
<subject>Just saying hi</subject>
<body>Hello Juliet!</body>
</message>
Example 6. Local Client Requests to Forward Unread Messages Currently Residing at the Remote Client
<iq from='juliet@example.com/chamber'
to='juliet@example.com/balcony'
type='set'
id='forward-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
action='execute'
node='http://jabber.org/protocol/rc#forward'
sessionid='forward:20040727T0337Z'/>
</iq>
Example 7. Remote Client Forwards All Unread Messages to Local Client
<message from='juliet@example.com/balcony'
to='juliet@example.com/chamber'>
<subject>Just saying hi</subject>
<body>Hello Juliet!</body>
<addresses xmlns='http://jabber.org/protocol/address'>
<address type='ofrom' jid='romeo@example.com/orchard'/>
</addresses>
</message>
Example 8. Remote Client Informs Local Client of Completion
<iq from='juliet@example.com/balcony'
to='juliet@example.com/chamber'
type='result'
id='forward-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#forward'
sessionid='forward:20040727T0337Z'
status='completed'/>
</iq>
It might be desirable to remotely set some run-time options of a client. For example, when neighbours complain about the sounds your client makes while you're at another location, you could turn the sounds off at the remote client.
Example 9. Local Client Requests to Change Options of a Remote Client
<iq from='juliet@example.com/chamber'
to='juliet@example.com/balcony'
type='set'
id='set-options-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
action='execute'
node='http://jabber.org/protocol/rc#set-options'/>
</iq>
Unless an error occurs (see the Error Handling section below), the service SHOULD return the appropriate form.
Example 10. Remote Client Replies with a Form to Set its Options
<iq from='juliet@example.com/balcony'
to='juliet@example.com/chamber'
type='result'
id='set-options-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#set-options'
sessionid='set-options:20040727T0337Z'
status='executing'>
<x xmlns='jabber:x:data' type='form'>
<title>Set Options</title>
<instructions>Set the desired options</instructions>
<field type='hidden' var='FORM_TYPE'>
<value>http://jabber.org/protocol/rc</value>
</field>
<field label='Play sounds'
type='boolean'
var='sounds'>
<value>1</value>
</field>
<field label='Automatically Go Offline when Idle'
type='boolean'
var='auto-offline'>
<value>0</value>
</field>
<field label='Automatically Open New Messages'
type='boolean'
var='auto-msg'>
<value>0</value>
</field>
<field label='Automatically Authorize Contacts'
type='boolean'
var='auto-auth'>
<value>0</value>
</field>
</x>
</command>
</iq>
Example 11. Local Client Submits Set Options Form to Remote Client
<iq from='juliet@example.com/chamber'
to='juliet@example.com/balcony'
type='set'
id='set-options-2'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#set-options'
sessionid='set-options:20040727T0337Z'>
<x xmlns='jabber:x:data' type='form'>
<field type='hidden' var='FORM_TYPE'>
<value>http://jabber.org/protocol/rc</value>
</field>
<field type='boolean' var='sounds'>
<value>0</value>
</field>
<field type='boolean' var='auto-offline'>
<value>0</value>
</field>
<field type='boolean' var='auto-msg'>
<value>0</value>
</field>
<field type='boolean' var='auto-files'>
<value>0</value>
</field>
<field type='boolean' var='auto-auth'>
<value>0</value>
</field>
</x>
</command>
</iq>
The remote client sets the values of the options to their requested value. If a variable is omitted, the client SHOULD NOT change the value of the corresponding option.
Example 12. Remote Client Informs Local Client of Completion
<iq from='juliet@example.com/balcony'
to='juliet@example.com/chamber'
type='result'
id='set-options-2'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#set-options'
sessionid='set-options:20040727T0337Z'
status='completed'/>
</iq>
Notification of completion MAY include the processed data in a data form of type 'result'.
Example 13. Local Client Requests to Accept Pending File Transfer Requests on the Remote Client
<iq from='juliet@example.com/chamber'
to='juliet@example.com/balcony'
type='set'
id='accept-files-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
action='execute'
node='http://jabber.org/protocol/rc#accept-files'/>
</iq>
Unless an error occurs (see the Error Handling section below), the service SHOULD return the appropriate form.
Example 14. Remote Client Replies with a Form Containing Pending File Transfers
<iq from='juliet@example.com/balcony'
to='juliet@example.com/chamber'
type='result'
id='accept-files-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#accept-files'
sessionid='set-status:20040727T0337Z'
status='executing'>
<x xmlns='jabber:x:data' type='form'>
<title>Pending File Transfers</title>
<instructions>Select the pending file transfers to accept</instructions>
<field type='hidden' var='FORM_TYPE'>
<value>http://jabber.org/protocol/rc</value>
</field>
<field label='Files'
type='list-multi'
var='files'>
<required/>
<option label='ballad.ogg (romeo@example.com)'>
<value>romeo@example.com/orchard:1</value>
</option>
<option label='picture.jpg (romeo@example.com)'>
<value>romeo@example.com/orchard:2</value>
</option>
<option label='challenge.txt (mercutio@example.com)'>
<value>mercutio@example.com/orchard:1</value>
</option>
</field>
</x>
</command>
</iq>
Example 15. Local Client Submits Form to Remote Client
<iq from='juliet@example.com/chamber'
to='juliet@example.com/balcony'
type='set'
id='accept-files-2'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#accept-files'
sessionid='accept-files:20040727T0337Z'>
<x xmlns='jabber:x:data' type='form'>
<field type='hidden' var='FORM_TYPE'>
<value>http://jabber.org/protocol/rc</value>
</field>
<field type='list-multi' var='files'>
<value>romeo@example.com/orchard:2</value>
</field>
</x>
</command>
</iq>
Example 16. Remote Client Informs Local Client of Completion
<iq from='juliet@example.com/balcony'
to='juliet@example.com/chamber'
type='result'
id='accept-files-2'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#accept-files'
sessionid='accept-files:20040727T0337Z'
status='completed'/>
</iq>
Example 17. Local Client Requests the Remote Client to Leave Groupchats
<iq from='juliet@example.com/chamber'
to='juliet@example.com/balcony'
type='set'
id='leave-groupchats-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
action='execute'
node='http://jabber.org/protocol/rc#leave-groupchats'/>
</iq>
Example 18. Remote Client Replies with a Form with a List of Groupchats it is currently in
<iq from='juliet@example.com/balcony'
to='juliet@example.com/chamber'
type='result'
id='leave-groupchats-1'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#leave-groupchats'
sessionid='leave-groupchats:20040727T0337Z'
status='executing'>
<x xmlns='jabber:x:data' type='form'>
<title>Leave Groupchats</title>
<instructions>Choose the groupchats you want to leave</instructions>
<field type='hidden' var='FORM_TYPE'>
<value>http://jabber.org/protocol/rc</value>
</field>
<field label='Groupchats'
type='list-multi'
var='groupchats'>
<required/>
<option label='juliet on jdev@conference.jabber.org'>
<value>jdev@conference.jabber.org/juliet</value>
</option>
<option label='juliette on jdev@conference.jabber.org'>
<value>jdev@conference.jabber.org/juliette</value>
</option>
<option label='juliet on girlsonly@jabber.com'>
<value>girlsonly@jabber.com/juliet</value>
</option>
</field>
</x>
</command>
</iq>
Example 19. Local Client Submits Form to Remote Client
<iq from='juliet@example.com/chamber'
to='juliet@example.com/balcony'
type='set'
id='leave-groupchats-2'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#leave-groupchats'
sessionid='leave-groupchats:20040727T0337Z'>
<x xmlns='jabber:x:data' type='form'>
<field type='hidden' var='FORM_TYPE'>
<value>http://jabber.org/protocol/rc</value>
</field>
<field type='list-multi' var='groupchats'>
<value>jdev@conference.jabber.org/juliet</value>
<value>girlsonly@jabber.com/juliet</value>
</field>
</x>
</command>
</iq>
The remote client leaves the requested groupchats, and informs the local client of completion.
Example 20. Remote Client Informs Local Client of Completion
<iq from='juliet@example.com/balcony'
to='juliet@example.com/chamber'
type='result'
id='leave-groupchats-2'
xml:lang='en'>
<command xmlns='http://jabber.org/protocol/commands'
node='http://jabber.org/protocol/rc#leave-groupchats'
sessionid='leave-groupchats:20040727T0337Z'
status='completed'/>
</iq>
Several error conditions are possible when an entity sends a command request to the service, as defined in the following table. If one of these errors occurs, the service MUST return an error stanza to the requesting entity.
Table 1: Error Conditions
| Condition | Cause |
|---|---|
| <feature-not-implemented/> | The specific command is not supported (even though the ad-hoc commands protocol is) |
| <forbidden/> | The requesting entity does not have sufficient privileges to perform the command |
| <service-unavailable/> | The ad-hoc commands protocol is not supported |
For the syntax of these errors, see Error Condition Mappings [5]. Naturally, other errors may be returned as well.
Implementations of this protocol MAY add or remove fields to forms as they see fit. For example, when setting the status of a remote client that supports multiple accounts, the client may choose to add a boolean field to allow the user to specify whether the status change should be applied globally or only to the receiving account.
Implementations MAY also introduce extra forms for commands. For example, when forwarding unread messages, a client could return a form containing a list of short descriptions of unread messages, allowing the user to select the messages he wants to forward.
The ability to complete the tasks specified herein MUST NOT be granted to users who lack privileges to control a client. A sensible access policy is to only allow remote controlling by other resources of the same account used by the client. If other accounts are to be able to remote control the client, the client needs more complex access right management.
This JEP requires no interaction with the Internet Assigned Numbers Authority (IANA) [6].
The Jabber Registrar [7] shall include the following information in its registries.
The Jabber Registrar shall include 'http://jabber.org/protocol/rc' in its registry of protocol namespaces.
Field Standardization for Data Forms [8] defines a process for standardizing the fields used within Data Forms scoped by a particular namespace. The reserved fields for the 'http://jabber.org/protocol/rc' namespace are specified below.
Registry Submission
<form_type>
<name>http://jabber.org/protocol/rc</name>
<doc>JEP-0144</doc>
<desc>Forms used for remote controlling clients</desc>
<field var='status'
type='list-single'
var='The list of statuses'/>
<field var='status-priority'
type='text-single'
var='The new priority for the client'/>
<field var='status-message'
type='text-multi'
label='The status message text'/>
</form_type>
Because the protocol defined here is a profile of JEP-0050: Ad-Hoc Commands, no schema definition is needed.
1. JEP-0050: Ad-Hoc Commands <http://www.jabber.org/jeps/jep-0050.html>.
2. JEP-0030: Service Discovery <http://www.jabber.org/jeps/jep-0030.html>.
3. JEP-0115: Entity Capabilities <http://www.jabber.org/jeps/jep-0115.html>.
4. JEP-0033: Extended Stanza Addressing <http://www.jabber.org/jeps/jep-0033.html>.
5. JEP-0086: Error Condition Mappings <http://www.jabber.org/jeps/jep-0086.html>.
6. The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>.
7. The Jabber Registrar maintains a list of reserved Jabber protocol namespaces as well as registries of parameters used in the context of protocols approved by the Jabber Software Foundation. For further information, see <http://www.jabber.org/registrar/>.
8. JEP-0068: Field Data Standardization for Data Forms <http://www.jabber.org/jeps/jep-0068.html>.
END