umple
Allow collaborative text editing like in Google Docs
This would be challenging, but it would be super-useful if an UmpleOnline mode could be created that would allow multiple people to edit the model simultaneously like in Google Docs.
Best if it could be done with multiple people but at least 2,
Currently text editing uses CodeMirror. It would be necessary to transmit every keystroke in both directions without disrupting what the other is typing.
Since we don't want to require 'accounts' an invitee would have to be given a special code, stored in the session directory, to allow them to collaborate with the original author.
Some constraints and ideas on this:
Umple is login-free and we want to keep it that way. Access to a repo is by a code (URL) that gives access to the data in a relevant directory in umpleonline/ump ... so in this feature, the person who initiates sharing would be granting other users access to that same directory.
This would not work on 'tmp' session directories, so it would imply making a 'bookmarkable URL' if that has not already been done.
To keep it simple, I suggest a button be added that says 'collaborate ' . That would make available a link that could be sent to the others (the user would copy the URL and send it by whatever means they prefer ... text, email. etc.)
Collaboration should be symmetric. Once it is initiated, all Umpleonline sessions operating on the same directory (including the initiator) would be the same.
Although UmpleOnline is login-less, during the process of setting up a collaboration, there should be a field where the initiator can enter an ID (this should be non-modal). That would make their presence visible to others and would help control the data flow. This ID could be a field in the app that would be always visible and editable even, and likely transmitted with each request. One option would be that a random short id could be set up initially.
The 'collaborating' status would have to be recorded in the shared directory, so that any new access to that directory would require an id before allowing editing.
Some kind of peer to peer arrangement would be needed: Each collaborating session would need to watch for edits from the others. I suggest these be sents as 'diffs' of each ump file (there can be multiple active ump files) that could be applied to the text on the screen if the same ump file is being edited by the other collaborator. Ideally this would be applied as unobtrusively as possible, so if both are editing the text of both displays. Maybe recent text by others appears in a different colour, or a message appears for a few seconds.
If a diagram is edited, this would also update the text, so the text should be primary,.
Different collaborators may be showing different diagram types.
If different collaborators are editing different files, then it is still possible that a diagram update may be needed if there is a use statement between the files.
This needs to be done without adding excess dependencies to Umple.
We have noted that CodeMirror will need to be updated. Either to 6.x or perhaps 5.x
Here is some info on collaboration in CodeMirror https://codemirror.net/examples/collab/