Off hours access token refresh

[BobGlicksman]

The current station firmware checks to see if the Amilia access token is valid at about 8 am each day. If the token has expired, a new token is obtained so that the token shouldn't need to be refreshed during normal operational hours. However, if a station is powered up during the day and needs a new token, it will get a token that is not refreshed the next 8 am but will need to be refreshed in the middle of the operational day. Also, tokens are set to expire (by us) about 1 second less than 24 hours since the token was obtained, which means that the 8 am check (which has a little randomness to its time) may or may not detect a token that is about to expire, meaning that a new token will need to be gotten when the station is next operated.

Perhaps we should (a) always get a new token at 8 am each day, regardless of whether the current token has expired or not, or (b) set the token lifetime to be e.g. 23 hours, so that a token gotten at about 8 am one day will have expired at 8 am the next day.

The occasional getting a new token does not take very long with Amilia, so this is not an urgent issue. However, it would be best to ensure that we have a fresh token at 8 am each day, so that a new token will only be needed during the operational day if the station is power-cycled.

[jschrempp]

As I understand it, the stations all do a reboot at 1am; they do not get a token at that time. A reboot invalidates the current token - the global variables are reinitialized on reboot.

If someone taps a card, the station will examine the token expiration time and get a new one if needed. The tap will take a bit longer to complete, but should not fail.

Between the hours of 8am and 11pm the station will periodically check the token expiration time. If the token will expire within the next 60 (?) seconds, then the station will proactively request a new token.

The Amilia tokens are good for one year, but we artificially set the expiration time to one second less than 24 hours.