View source for Features/Fixing Collab (Tubes)

= Fixing Collaboration (Tubes) =

== Summary ==

Collaboration (hereon called collab) is build upon a framework called telepathy. Many years ago, the Telepathy Tubes (one type of channel) was deprecated. They have now been removed from telepathy (Fedora 22+) and therefore sugar collab does not work on newer systems.

This feature is to migrate to a new method, as well as moving the boilerplate code that activities use to do collab into an abstraction for easy porting.

== Background ==

Sugar uses telepathy to do collab. Lets look a how telepathy works from my understanding:

* Accounts (eg. jabber server, salut local network link)
* Connections - when you connect to a buddy over an account
* Channels - using a connection, you can make a channel to send data to a buddy

Let's look at some of the types of channels:

* Text - you can send text. Used for IM applications, but realistically can be used to transfer any text data. Chat activity uses this
* FileTransfer - a buddy can offer to send another buddy a file, which can be backed by anything (eg. can be send from memory to memory)
* DBusTube - a shared dbus thing
* StreamTube - shared socket thing
* Tubes - DEPRECATED. Many sugar activities use this. It is like a whole connection due to the fact that you can negotiate other tubes over your Tubes channel. For design reasons, it got replaces by DBusTUbe and StreamTube channels.

== Scope ==

# Sugar toolkit negotiates channels for the activity. It gives them a text and tubes channel. This is where the error happens, and must be changed to only give the activity a text channel. However, since OLPC OS still supports tubes, this should be behind a flag.  (namely, the gsetting org.sugarlabs.collaboration.tubes-supported).  See https://github.com/sugarlabs/sugar-toolkit-gtk3/pull/282 (and the required https://github.com/sugarlabs/sugar/pull/644)
# Activities that depend on tubes now don't work. Hypothetically, they could be ported to use DBusTube and StreamTube channels. However, that is very hard and generally a massive pain, given that most activities have about 150 lines of slightly varying boilerplate tube negotiation. This can be replaced with a high level abstraction, so that the activity only deals with what data to send, rather than how to send that data. See https://github.com/sugarlabs/sugar-toolkit-gtk3/pull/272
# However, some activities need to send large blobs to single buddies (eg. a new buddy joins read, needs a copy of the file). This is not suited to a json encoded message. However, we can use FileTransfer tubes (see the patch above). However, the shell currently claims all file transfers, so we need to have a special identifier for the shell to know to disregard these, see https://github.com/sugarlabs/sugar/pull/621
# All activities (other than Chat) need to be ported to the collab wrapper
# To maintain backwards compatability for activities, they can use a polyfill version of the CollabWrapper, see https://github.com/walterbender/physics/pull/10

= Benefit to Sugar =

For users, they get working collab on newer platforms.

For developers, they get a high level api that makes it easy to add collab to their activities. They no longer need to add 150 lines of confusing tube negotiation boilerplate or reinvent a message passing system.

= UI Design =

N/A

= How to test =

Run activities. Share them between computers with the patch, and old (fedora 18) XOs. See them working together.

This is TODO.

= Dependencies =

None

= Contingency Plan =

Collab will be broken again.

= Release Notes =

Sugar now sports a brand new collaboration engine that makes collaboration work in new and exciting places. Developers can now use the new CollabWrapper API to enable collaboration in their activities with ease.