WFS: correct data types for describefeaturetype

[havatv]

In the WFS (and WMS) server documentation, gml_[item name]_type is used to specify the type of the non-spatial properties of a feature. Currently the documentation is:

gml_[item name]_type (Optional) Specifies the type of the attribute.
Valid values are Integer|Real|Character|Date|Boolean.

The value specified in gml_[item name]_type is used as it is in the describefeaturetype response, so I guess that the values need to be valid GML types.

An overview of the XML schema type library can be found in: http://books.xmlschemata.org/relaxng/relax-CHP-8-SECT-1.html

"Real" and "Character" are not mentioned there, and "Integer", "Date" and "Boolean" are all specified with a lower case first letter.
I assume that "double" could be used instead of "Real", and "string" instead of "Character".

What should we write in the gml_[item name]_type documentation?
I think we need to say that the values need to be valid GML or XML data types. But should we give directions when it comes to which of the valid GML or XML data types that should be used? Should only primitive types be allowed?
Should a prefix (for example "xsd:") be mandatory?

Relevant open issue: MapServer/MapServer#462

[rouault]

I think that it is not a documentation issue but an implementation one. See MapServer/MapServer#4800 I've just created related to that

[havatv]

Thank you, @rouault for the clarification. However, the documentation could perhaps be made clearer / more informative.
Should OGR be mentioned?
I am not sure if I read your code right, but should it be mentioned that it is possible to use other data types - the OGR data types mentioned in the docs are "translated", but other data types are just sent as they are specified (e.g. "xsd:double")?

[rouault]

@havatv if you have ideas how to make the doc clearer, don't hesitate. Actually OGR is mentionned in the doc of the "gml_types" option. But the precision "Currently this is only used for OGR based output formats, not the WFS GML2/GML3 output" is no longer true since my fix. Actually DescribeFeatureType will now take into account item type, either if it is specified manually with gml_[item_name]_type or gml_types = "auto"

As far as mentionning that other data types are sent as they are specified, this is no longer true. It should not be advertized. It is just a way of keeping backward compatibility if people used xsd types into gml_[item_name]_type even if it was not legal. Users should only use the advertized types "Integer|Real|Character|Date|Boolean" since it is the only "universal" way of specifying them in MapServer internals.

[havatv]

Thank you for the clarification, @rouault .
Your fix has not yet made it into the current release, so it could perhaps be useful to mention this problem in the 6.4 documentation for the time being?

[rouault]

Yes, probably. But the next point release of 6.4 will have the fix. I'm now wondering if it was appropriate to push it in the 6.4 branch if ever people relied on the undocumented behaviour...

[havatv]

I suggest we leave this open until @rouault 's fixes has made it to the current release. Then the note should be removed.