It's an older post, from 2016 when there were no Extension support. With Tableau Extension API you can do the same without going "unsupported".
Is there anything you need not in the Extensions API?
Agree Tamas Foldi I have switched to Extension API and able to solve all the issue which I was facing before.
But one thing I am not able to know is whether a dim/fact is placed on a row or column field on a Tableau worksheet. I have asked the same question on the Tableau community here
Another question, as Tableau Extension needs a separate https server to host the HTML and JS scripts. What I tried was your technique and used 'tabadmin import_webdataconnector' to add all HTML and JS files. And it works. So is this ok to do or this comes under "going unsupported"?
you can still use tabadmin import_webdataconnector as long as you are on an older version of the server. in the new version, you simply do not have that function. Still, you can use tableau server to host your extensions: just copy the files to gateway's webroot. However, it is easier to host your extensions on github or other providers who supports static page hosting.
At the moment you cannot get the dim/fact information using extension api. The best you can do is get this information using the new metadata api (graphql). Like the extension will get the workbook name and sheetname, underlying data and calls metadata api to obtain the object level information dim-measures.