Minimum value for "limit" too restrictive (0 should be allowed)

[ycespb]

The requirement (20) /req/core/fc-limit-definition combined with permission 5 in OGC 17-069r2 do not allow to make queries with "limit=0" to allow a client to count results without actually retrieving results (This is currently used by clients/servers implementing EO OpenSearch in a distributed context and related CEOS Best Practices). It requires that at least one result is requested/returned. Propose to relax this and either allow 0 or state in permission 5 that the value for "minimum" is also an example.

[cportele]

I see, you are using limit=0 to mimic the resultType=hits behavior from WFS 2.0. Originally this was part of the Core, but we moved it out (#22) early in the process.

Allowing limit=0 to achieve this could be an option. It wouldn't make it a requirement to support such a capability (it would be up to the implementing software) and at the same time we wouldn't need an extension to support the capability.

[pvretano]

This bring up an interesting point related to HEAD. What about defining a set of OGC headers that return information similar to what we used to be able to get with resultType=hits?
The idea is, someone does a HEAD request and gets back something like an OGC-NumberMatched header or something like that... I would prefer this to limit=0. In my mind, limit=0 simply returns an empty container whose content is dependent on the output format and may or may not contain information similar to resultType=hits.

[cportele]

Yes, using HEAD would be cleaner, but it clearly would be an extension. limit=0 is somewhat of a hack, but not a bad one.

Maybe one way to do it would be to just allow that servers can state other "minimum" values for limit than 1 (including values>1, maybe someone has such a requirement, too), but do not mention/discuss limit=0. And for the proper approach work on a HEAD extension?

[cportele]

SWG call 2019-08-12: Clemens to create a pull request (see previous comment). Close this issue and open a new one to work on a HEAD extension.