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The idea is to combine multiple backend systems of same or different type behind a single web address or web origin. An origin is the combination of protocol, host and port. Can this be done with Web Dispatcher? Actually, this is not a Web Dispatcher question, the question is rather whether this is possible at all.

There are two variants to this question:

First scenario: Use additional URL prefixes to address multiple backend systems

For each system, an URL prefix would be added in front of the path to identify the system. The prefix could be either removed by the Web Dispatcher or tolerated by the backend system.

Example:

  • Web Dispatcher would run on https://web.acme.com. Backend systems would be addressed with the following URLs:
     
  • Path prefix /erp1 should reach an SAP ERP system
  • Path prefix /erp2 should reach another SAP ERP system
  • Path prefix /pi would reach an SAP PI system
  • Path prefix /ep should reach an SAP Enterprise Portal system

Unfortunately, the general answer is No. There are two major reasons:

  • When backend systems generate URLs, they are not prepared to generate such a variable prefix.
  • Cookies issued to path "/" would clash.

Therefore, SAP does not support adding a prefix in front of system paths to identify multiple backend systems. Instead, each backend system should be addressed by a different hostname.

Second scenario: Partition the path tree of all backend systems and route request accordingly

Differentiate backend systems by different paths to the applications.

Example: Web Dispatcher would run on https://web.acme.com. Backend systems would be addressed with the following URLs:

  • Web Dispatcher would run on https://web.acme.com. Backend systems would be addressed with the following URLs:
  • All path prefixes /sap/hba, /hana, /sap/hana and /sap/ui5 should be routed to an SAP HANA XS system
  • The path /sap/es/ina/ should be routed to an SAP ERP system
  • All remaining paths should be routed to an SAP Gateway system

Such a setup is possible, and is actually required for SAP Fiori to overcome the restrictions of the Same-origin policy. However, only specific combinations of systems are possible, because.

  • Cookies issued to path "/" would clash.
  • Overlapping resources must be avoided.

In general, systems of different type can be combined like this, because they have no clashes and no overlapping resources. Systems of same type, like two ABAP systems, cannot be combined. The only exception is that web services (OData, INA search protocol, SOAP) from multiple ABAP systems can be combined. Only one ABAP system may provide the web user interface, like SAP UI5 or WebDynpro.

 

 

 

 

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