Add an option to filter out empty rooms in room list

[JOJ0]

as discussed in #synadm:peek-a-boo.at (specific message)

To be decicded:

• Should it really be an option in synadm room list that just shows empty rooms and purging has to be done using jq/shell magic/looping and invoking synadm room delete?
• or rather be a separate command named something like synadm room purge-empty (similar to synadm user prune-devices
• Or even both?

[erdnaxeli]

I am for the synadm room purge-empty 👍

[JOJ0]

Hi @erdnaxeli, thanks for the vote! Yes I like the separate purge/prune command as well and will implement it. Nonetheless I had started already to implement a --empty flag to the room list command. It turned out that it it's not as straight forward as I thought due the pagination features. I kind of solved it but rather ugly, quick and dirty. This is the feature draft for now but I am not really happy with it. If you have a minute, give it a try on your server: https://github.com/JOJ0/synadm/tree/room_empty
I would welcome any input on how to proceed with this.

[JacksonChen666]

synadm room purge-empty was implemented in 48fa5de.

synadm room list --empty was not implemented because that had shortcomings (needing the right sorting arguments, plus room listing is technically already implemented via synadm room purge-empty).