SAP Function Module SCMS_AO_URL_READ Returns a Communications Error when called from the SAP Portal

Question

We have upgraded our development SAP system from (ECC6 and SAP Portal) from SPS3 to SPS5.

Now when a user logs onto the SAP Portal and run a bespoke Java Web Dynpro screen (which in turn calls SAP standard Function Module SCMS_AO_URL_READ in order to retrieve a UWL), an exception is returned.

When the Function Module SCMS_AO_URL_READ is manually called from the SAP ECC system (by running transaction SE37 from the SAP GUI) and the same parameters are passed, no exception is returned.

Investigation has shown that the failure occurs when SAP standard Function Module RFC_PING for destination SAPGUI is called (the call sequence is SCMS_AO_URL_READ -> SCMS_DOC_URL_READ -> SCMS_URL_GENERATE -> perform location_from_client -> perform location_from_lca -> SCMS_LOCATION_GET -> SCMS_FE_CHECK_REG_SERVER -> SCMS_FE_CHECK_GUI -> RFC_PING). The exception 'Communication failure' is being returned.

This error did not occur pre-patching, or in an identical system that we have which has not been patched.

Any ideas why the parameters are not being automatically populated?

Thanks.

Answer 1

I don't know the details of the function modules involved, but the purpose is clear - the program wants to make sure that a "real" SAP GUI is present, and obviously that's not the case when you're in the WebDynpro world. The RFC destination SAPGUI is a "virtual" destination that always points "back" to the GUI instance of the user session executing the program. I'd recommend creating a SAPnet message and asking SAP directly.

Answer 2

After further investigation we found that the issue is caused when the user has access to the Authorisation Object S_RFC_ADM.

I do not know why this is yet (especially as SAP authorisations are supposed to be accumulative and not have exclusions), but that is definitely the issue.