?_ttl= parameter to control caching

[simonw]

This would allow clients to specify the max-age caching header that should be returned with the query.

Most important this will allow caching to be completely urned off for specific queries using ?_ttl=0. Sending 0 should cause a Cache-Control: no-cache header to be returned.

[simonw]

An example of a query where you might want to use this option: https://fivethirtyeight.datasettes.com/fivethirtyeight-5de27e3?sql=select+rowid%2C+*+from+%5Balcohol-consumption%2Fdrinks%5D+order+by+random%28%29+limit+1

[simonw]

Documented here https://datasette.readthedocs.io/en/latest/json_api.html#special-table-arguments and here: https://datasette.readthedocs.io/en/latest/config.html#default-cache-ttl

[simonw]

Demo: hit refresh on https://fivethirtyeight.datasettes.com/fivethirtyeight-5de27e3?sql=select+rowid%2C+*+from+%5Balcohol-consumption%2Fdrinks%5D+order+by+random%28%29+limit+1&_ttl=0