Hello, colleagues,
I am exploring the HANA Cloud platform and want to implement simple scenario with UI5 frontend and HANA XS backend.
Both parts are running in the same trial account.
When XS service is called from the UI5 app, the call is failing with error with following message:
HTTP Status 500 - System headers cannot be generated due to : com.sap.core.connectivity.httpdestination.common.HeaderGenerationException: com.sap.security.saml2.lib.common.SAML2Exception: Failed to sign the Assertion
I have set the destination for UI5 application via neo-app.json which should point to the xsjs file that should provide me the test data.
.xsaccess file content is following:
{
"exposed" : true
}When accessed directly, xsjs service works perfectly, presenting me SAP ID Service authentication dialog, and then -- desired content.
UI5 destination is configured in the cockpit with authentication like this:
When I have changed the authentication method to the NoAuthentication and changed the .xsaccess to eliminate authentication, the XS service had been called smoothly.
How should I set authentication for the destination to allow XS service to be protected by SAP ID Service, but to be able to call it from the UI5 application authenticated by the same method? Does cloud HANA support this? I just cannot get how to glue it together. 
I also interested in the way to obtain information about authenticated user (name, attributes, etc).