improve TMS imagery caching

[bastiK]

Currently, the TMS caching is a little strange:

(1)

• After first download, the offline cache will be used for 7 days.
• From that point on, the check period is reduced to 1 day.

A check is as good as a download, so instead it should only check after another 7 days, and so on.

(2)

• When cache is stale, and image cannot be downloaded (e.g. no network connection), it displays no tile.

Instead, the old cached image should be used. This is better than displaying nothing.

[bastiK]

In [o30849].

[skyper]

Replying to bastiK:

Currently, the TMS caching is a little strange:

(1)

• After first download, the offline cache will be used for 7 days.
• From that point on, the check period is reduced to 1 day.

Are these periods configurable ? I'd like to check every 24h as a check is fast but waiting seven days is quite a long time in a world of seconds or below.

[bastiK]

In [o30850] - see ​#josm10849 - minor fixes for TMS cache handling.

[bastiK]

Replying to skyper:

Replying to bastiK:

Currently, the TMS caching is a little strange:

(1)

• After first download, the offline cache will be used for 7 days.
• From that point on, the check period is reduced to 1 day.

Are these periods configurable ? I'd like to check every 24h as a check is fast but waiting seven days is quite a long time in a world of seconds or below.

7 days seems okay for aerial imagery, with update periods of one year or more. But the OSM tiles should probably be checked every day or more, as the user probably want to see their own edits on the map as soon as possible.

[Don-vip]

finish all cache-related tickets next month

[stoecker]

Again delayed.

[wiktorn]

Fixed within #11193