Expiring all the schedules and playing a default layout on a button click

[alex]

Have a look at this first:

How do Players communicate with the CMS?

All signage players supporting the Xibo CMS communicate over “web services”. These are available on the CMS via normal HTTP or secure HTTPS connections (the same communication method used to view web pages). Each player has a Collection Interval which determines how often they connect to the CMS to download updated schedule information and new content. There are 8 pieces of information regularly exchanged between Players and the CMS. Register Required Files Schedule File Download Resource Do…

It explains how the players communicate with the CMS, and that should explain why doing anything from the CMS instantly on the Player is not possible within the current model.

You would need to engineer some kind of push mechanism (and deal with firewall/NAT traversal) for that to work.

If you’re happy to wait long enough for the client to connect to the CMS before the change took effect, then you could just intercept the output of the Schedule call and change that so that nothing was scheduled, in which case the default layout would play.