SOAP : WSDL with includes fails parsing

[driesva]

We have been provided a large set of WSDLs as an artifact. These WSDLs are including their schemas through xs:include using a relative path. Schemas are also located in a hierarchical structure.

When configuring such a WSDL in Imposter, we encounter a Schema compilation error.
In the end it turns out to be an XmlBeans error:
Caused by: org.apache.xmlbeans.XmlException: error: Could not load resource "schema-include.xsd" (network downloads disabled).

I found issue https://issues.apache.org/jira/browse/XMLBEANS-479 but when enabling downloads (using XmlOptions().setCompileDownloadUrls()) other issues appear (with existing tests):
Caused by: org.apache.xmlbeans.XmlException: error: URL "schema.xsd" is not well-formed
(Error is also mentioned in comments of that XmlBeans issue, however issue is resolved...)

A quick solution I've found was to provide a custom entity resolver using
XmlOptions().setEntityResolver(...). That entity resolver will look for XML schemas relative to the configured WSDL.

This worked for the parsing part. However the same problem appears when generating sample responses in SoapExampleService by calling XmlBean's SchemaInstanceGenerator. The latter does not let you configure XmlOptions directly.

Therefore the alternative I found was to configure this entity resolver globally. This was however a challenge on its own as the resolver needs the WSDL path, which is config specific. Given multiple threads are being used, I opted for a ThreadLocal.

I'll provide a PR with these changes.

[outofcoffee]

Thank you very much for your work on this @driesva.

Released in v3.36.3.