DescribeFeatureType reponse of deegree WFS causes ArcGIS online to fail

[tfr42]

The issues we've been having is that most of our services using deegree either do not open, or do not show any data when using ArcGIS online as a client. We don't get any useful error messages back unfortunately.
We think it's a DescribeFeatureType issue, so we've been doing some more research (with both QGIS and ArcGis Online) and what we've found out is that the configuration of DisableDynamicSchema is relevant. Either the returned schema is not valid or the clients can not process the response of the DescribeFeatureType request.
We're assuming is that the only way our services can work in ArcGIS online (and with a schema that validates), is if the response from a DescribeFeatureType request is a full schema coming directly from the file system or external resources.

[tfr42]

Reproducer will be setup with deegree 3.4.12 + merged PR #1005

The issue may relates to #892 and #455

[tfr42]

Currently the deegree WFS returns for a DescribeFeatureType response the defined XSD using a W3C XSD include element. This include element provides support for schema modularity in which an XML schema can be partitioned into more than one physical file.

Some WFS clients such as ArcGIS Online currently does not support this element in the DescribeFeatureType response. XML schemas that include this element will be rejected by the server.

As a solution, XML schemas that include the <xsd:include> directive can be preprocessed to copy and merge the contents of any included schemas into a single schema for uploading to the server.

When one single XSD file is present in the workspace or referenced locally by the SQLFeatureStore configuration deegree shall return this XSD file directly.

[tfr42]

The proposed solution shall return a XSD file from deegree workspace as it is in the response of a DescribeFeatureType request.
As a prequisite a <SQLFeatureStore/> shall contain only one element of <GMLSchema/> pointing to a local file, e.g.:

<SQLFeatureStore configVersion="3.4.0" xmlns="http://www.deegree.org/datasource/feature/sql" xmlns:app="http://domain.com/path/to/xsd/Schema/Version" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.deegree.org/datasource/feature/sql
  http://schemas.deegree.org/datasource/feature/sql/3.4.0/sql.xsd">
   <JDBCConnId>testdata</JDBCConnId>
   <StorageCRS srid="4326" dim="2D">EPSG:4326</StorageCRS>
   <GMLSchema>../../appschemas/MySchemaFile.xsd</GMLSchema>
   <FeatureTypeMapping>
...
</SQLFeatureStore>

[tfr42]

A PR containing an enhanced XSD schema handling will be available soon.