CapabilitiesCacheHeadersCallback should not set eTag, causes clients to cache capabilities when dimension values changes

Description

Please see mailing list discussion.
http://osgeo-org.1560.x6.nabble.com/CapabilitiesCacheHeadersCallback-caches-getcap-inappropriately-Time-Series-td5315205.html

Main issue: not all catalog changes are detected, leading to caching issues. For example, security and adding/removing Dimensions (Time/Elevation).
Workaround: "-DCAPABILITIES_CACHE_CONTROL_ENABLED=false"


I noticed that the GetCap document was not up-to-date. When I dug into it, I found that CapabilitiesCacheHeadersCallback was returning a 304 (i.e. no changes).

However, this is a timeseries dataset (ie. Time Dimension tab on Layer Publish).

(i.e. a GeoGIG or PostGIS dataset with a time column)

The issue is that the dataset is changing. A new Time value is inserted into the dataset - the getcap (set to LIST) should show this new value. However, the document is cached because the catalog hasn't detected any changes.

We talked about this earlier ("Time dimension on Vector Layer is SLOW") and decided that caching this information is inappropriate (and I agree) for this reason.

Environment

None

Status

Assignee

Andrea Aime

Reporter

David Blasby

Triage

None

Fix versions

Affects versions

None

Components

Priority

Highest
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