SAP Cloud Connector: Connect to an On-Premises system when there is no transparent network connection
Configuring the SAP Cloud Connector to connect SAP Cloud Platform with an On-Premise network is a standardized and well documented process. As a prerequisite within all documentations a transparent network connection between SAP Cloud Connector and the backend system is mentioned. Transparent means that there is no third system that interferes the direct communication between SAP Cloud Connector and backend system. Now the question arises, what happens if we put a SAP Web Dispatcher in the transparent network connection that hides the ABAP system’s host name from the Cloud Connector? In this blog post, we would like to share a solution how you can make this scenario work.
In our architecture, we access an On-Premises ABAP System from SAP Web IDE located in the SAP Cloud Platform. The connection comprises four steps:
- WebIDE calls the destination which is configured in the connectivity service of the SAP Cloud Platform.
- The SCP Connectivity Service adds a virtual host to the request header and forwards the call to the SAP Cloud Connector.
- The SAP Cloud Connector maps the virtual host to the internal host. Since the ABAP System is not visible to the Cloud Connector, we must call the alias of the backend system.
- The SAP Web dispatcher takes the request, replaces the alias with the physical hostname and sends it to the ABAP system.
Our configuration includes two steps, first configuring the SAP Cloud Connector and second configuring the SAP Cloud Platform. We assume that the SAP Web Dispatcher is just translating the URL from alias to the real name.
In order to make the proposed architecture work, SAP Cloud Connector version 220.127.116.11 or higher is required, since there is a new parameter in the system mapping configuration called “Host in Request Header”. The parameter is responsible which hostname will be used when calling the backend system. Till SAP Cloud Connector 2.11 this option didn’t exist, and we saw from the log that always the virtual host was used in the request header, which lead to an error in the Web Dispatcher. In the subsequent screenshot the configuration of the system mapping is provided. As an internal host and port, you have to use the backend system’s alias. For the parameter “Host in Request Header” choose “Use Internal Host”. With this configuration, the SAP Web Dispatcher is able to recognize the alias URL and to rewrite it into the URL of the backend system.
Figure 1: SAP Cloud Connector: Configuration of system mapping
Once you have finished the cloud connector configuration, open the Connectivity Service in the SAP Cloud Platform and create a new destination. You can provide a name of your choice. The URL needs to match the pattern http://<Virtual Host>:<Virtual Port> with the values from the Cloud Connector and you have to add additional parameters in order to use the destination from within the SAP Web IDE. Detailed Information about all additional parameters available for SAP Web IDE can be found at SAP Help.
Figure 2: SAP Cloud Platform: Configuration of Connectivity Service
Once this configuration is done, you can access the backend system from SAP Web IDE and import projects from the backend system’s ABAP repository.
In this blog post, we provided a solution on how to connect SAP Cloud Connector to an ABAP backend system when there is no given transparent network connectivity. The key configurations are to upgrade the SAP Cloud Connector to version 18.104.22.168 and to set parameter “Host in Request Header” to “Use Internal Host”. With this configuration, the SAP Cloud Connector puts the internal Host name in the Request Header so that the requests can be processed by the Web Dispatcher.
About the authors
Michael Christa is SAP Consultant at Q_PERIOR focusing on technology and innovation. His professional interests are developing end-to-end SAPUI5 applications as well as working with the SAP Cloud Platform.
Ilan van der Borght
Ilan van der Borght is Cross Technology Consultant at Q_PERIOR focusing on technology and innovation. His professional interests are developing end-to-end SAPUI5 applications as well as integrating SAP and Non-SAP technologies.
Natalie Uhly is SAP Consultant at Q_PERIOR focusing on technology and innovation. Her professional interests cover ABAP including ABAP CDS and UI technologies especially SAPUI5.