This question made me think more about how best to store the document using a Python backend today if one is going make a release now where users expect to be able to upgrade to future versions.
We are currently storing full HTML of the document every 2 minutes + all the steps that have been sent since the last full update. We use PM 0.7.0 in the frontend and the backend doesn't understand the data.
This seems problematic, because if the structure of the steps change, and the administrator upgrades their version, then that will destroy the documents that contain unapplied steps that no longer work with the new transformation model.
I am thinking through a few solutions:
A) When the last collab user leaves a document, apply all unapplied steps serverside. Unfortunately this won't quite work, because even though there is PyV8, it doesn'thave a DOM, so it won't be able to load the document in HTML format.
B) Create a management page that an administrator can call from his/her browser which loads all the documents with unapplied changes and applies those changes and saves the document. The administrator is asked to do this before updating their server with any newer version.
C) Store both HTML and the PM document format on the server. Use the HTML for now, but for future versions plan on switching to the PM document format. Use PyV8 to apply unapplied steps to the PM document format version only whenever a document is closed.
I'm actually not sure which one makes more sense. It would be preferable though if one could find a solution so that we don't need to ship older versions of PM with future versions of our software just to be able to read the steps.
@matthieubellon: Is this a problem you guys are facing? If so, what are you doing about it?