jarn.xmpp.collaboration 0.1a2

Initialization

In order to initiate a collaborative editing session, the party sends a presence to the server indicating on which node he wishes to work on. The party MUST specify the node attribute in the query element:

<presence from='foo@example.com/work' to='collaboration.example.com'>
    <query xmlns='http://jarn.com/ns/collaborative-editing'
        node='collab-node'/>
</presence>

Upon receipt the server sends a message to the party setting the initial text of the node. If the node is already being edited the initial text is the most current copy on the server:

<message from='collaboration.example.com' to='foo@example.com/work'>
    <x xmlns='http://jarn.com/ns/collaborative-editing'>
        <item action='set' node='collab-node'>Hello world</item>
    </x>
</message>

Editing cycle

When a party edits the text, it notifies the server by sending a message. The message contains one or more item elements which MUST specify the node they apply to, have the attribute action set to patch, and in their body contain the patch created by the Diff-Match-Patch algorithm in text format. For instance if the text changed from “Hello world” to “Hello world, have a nice day!” the message would be:

<message from='foo@example.com/work' to='collaboration.example.com'>
    <x xmlns='http://jarn.com/ns/collaborative-editing'>
        <item node='collab-node' action='patch'>@@ -4,8 +4,26 @@\n lo world\n+, have a nice day!\n</item>
    </x>
</message>

If the server succeeds to apply the patch to its shadow copy, it broadcasts the patch to all other parties who are present on the node. The parties MUST apply it to their text:

<message from='collaboration.example.com' to='bar@example.com/home'>
    <x xmlns='http://jarn.com/ns/collaborative-editing'>
        <item node='collab-node' action='patch'>@@ -4,8 +4,26 @@\n lo world\n+, have a nice day!\n</item>
    </x>
</message>

If the server fails to apply the patch (because for instance there was a network problem and the client fell out of sync, or the diff-match-patch application failed), it SHOULD send a set action to the party with its shadow copy as text.

Focusing

In an environment where multiple nodes are edited in the same time (for instance in a context where the content has more than one collaboratively editable fields) the client CAN send a notification specifying which particular node he is currently editing:

<message from='foo@example.com/work' to='collaboration.example.com'>
    <x xmlns='http://jarn.com/ns/collaborative-editing'>
        <item node='collab-node' action='focus' user='foo@example.com/work'/>
    </x>
</message>

The server MUST propagate the message to all other users that are currently collaborating on the node:

<message from='collaboration.example.com' to='bar@example.com/home'>
    <x xmlns='http://jarn.com/ns/collaborative-editing'>
        <item node='collab-node' action='focus' user='foo@example.com/work'/>
    </x>
</message>

Saving

At any point a party can request a save. This is done by sending a message whose item MUST indicate the node and its action must be set to save:

<message from='foo@example.com/work' to='collaboration.example.com'>
    <x xmlns='http://jarn.com/ns/collaborative-editing'>
        <item node='collab-node' action='save'></item>
    </x>
</message>

It is up to the server component to enforce any security considerations on saving.

Termination

The session is terminated when the party sends an unavailable presence:

<presence from='foo@example.com/work' type='unavailable' />

0.1a2 - 2010-06-06

• Configure the component/server password and connection port in p.a.registry. [ggozad]

• Dexterity content type support. [davisagli, ggozad]

• Generalized ATContentTypes support. [ggozad]

• Provide visual feedback when a user updates a node. [ggozad]

• JS cleanup. [ggozad]

• Test coverage. [ggozad]

0.1a1 2010-05-09

• Initial release [ggozad]