Connect to Your On-Premise System from SAP BTP, ABAP Environment Using RFC

First, you need to connect your ABAP on-premise system to your BTP sub-account by means of SAP Cloud Connector.

1. In your browser, log on to SAP Cloud Connector:

   • Address = e.g. https://localhost:<port> (Default = 8443)
   • User = Administrator
   • Initial password = manage (You will change this when you first log in)

2. Your configuration should look like this.

   

> The Location ID is optional. It enables you to connect multiple Cloud Connectors to a subaccount.

1. In the menu in the left pane, expand the sub-account and choose Cloud To On-Premise > Access Control.

2. Note down the Virtual Host, e.g. s4h_rfc:sapgw<instance> as here. This represents an external hostname, so that you can hide the internal hostname from the outside world. You will need this external hostname and port later, when creating a destination from SAP BTP cockpit.

3. Check that Result = Reachable. If not, check that you chose the correct port, or whether an internal firewall is preventing communication.

   

4. Add the following resources:

   • RFC_GET_SYSTEM_INFO (as exact name)
   • BAPI_EPM (as prefix)
   

In the SAP BTP cockpit of your Cloud Foundry sub-account, choose Cloud Connectors:

The Virtual host points to the on-Premise connection mapped in SAP Cloud Connector. If used, The Location ID points to the correct SAP Cloud Connector (located in the on-Premise system). Later, in your Communication System in Fiori Launchpad, you will use these values, as and Target Host and (optionally) SCC Location ID respectively.

Now, in SAP BTP ABAP Environment, you need to create the necessary ABAP artifacts in ABAP Development Tools (ADT), starting with a package.

1. In ABAP Development Tools (ADT), select the ABAP Cloud Project and choose New > ABAP Package from the context menu.

2. Enter the following and choose Next:

   • Name = Z_OUTBOUND_RFC_###
   • Description = Get product data from S/4HANA using RFC
   • Package type = Development
   

3. Choose Create new transport request, enter a description, such as Get product data from S/4HANA using RFC, then choose Finish.

   

Next, you will establish outbound communication from the BTP instance to the S/4HANA instance.

1. Select your ABAP package and choose New > Other Repository Object from the context menu; then enter Outbound Service, then choose Next.

   

   
   
   

   

2. Enter the following and choose Next.

   • Outbound service: Z_OUTBOUND_RFC_###. The SRFC suffix will be added automatically.
   • Description: Get product data from S/4HANA using RFC
   • Service type: RFC Service
   

3. Choose the transport request you just created, then choose Finish.

The outbound service appears. Optional: Add the relevant RFC, RFC_GET_SYSTEM_INFO, then choose Save from the main toolbar.

1. Still in ADT, choose Cloud Communication Management > New > Communication Scenario from the context menu, then choose Next.

   

2. Enter the following and choose Next.

   • Name: Z_OUTBOUND_RFC_###_CSCEN
   • Description: Comm Scen: Call API from S/4HANA using RFC
   

3. Choose the transport request you just created, then choose Finish.

   The communication scenario appears in a new editor. Ensure the following have been entered:

   • Communication Scenario Type: Customer Managed
   • Allowed Instances: One instance per scenario and communication system

4. On the Outbound tab, add your service by choosing Add.

5. Choose Browse, select your outbound service Z_OUTBOUND_RFC_###_SRFC, then choose Finish. The service type RFC is entered automatically.

6. Choose Finish. Your communication scenario should look like this.

   Make sure that Supported Authentication Methods > Basic is ticked, since you will use this method later.

   

7. Leave the other default settings, choose Save, then choose Publish locally.

Now, you need to create the necessary communication artifacts in Fiori Launchpad (of the BTP instance), starting with the communication system.
This artifact specifies the URL of the API (minus the HTTP(S) protocol) and port.

1. In the Fiori Launchpad home page, choose Communication Systems, then choose New.

   step4a-comm-system

   

2. Enter the following and choose Create.

   • System ID: Z_OUTBOUND_RFC_CSYS_###
   • System Name: Z_OUTBOUND_RFC_CSYS_###

3. In General and below, enter:

   Field Name	Value
   Host name	the host name of your ABAP on-premise system, found in the URL of that system’s Fiori Launchpad, e.g.: myhost.s4hana.ondemand.com
   Port	Default = 443
   Destination	Off
   Cloud Connector	On
   SCC Location ID:	SAPDEV

4. In RFC Settings, enter:

   Load Balancing	Off
   Target Host	s4h_rfc
   Client	Client of your ABAP on-premise system, also found in the URL e.g. 100
   Instance Number	Default = 00

   

5. Under Users for Outbound Communication, enter the following, then choose Close:

   • Authentication method: User Name and Password (basic authentication)
   • User name: Your user name from the on-premise system
   • Password: Your password from the on-premise system
   

6. Leave the other default settings as they are and choose Save.

Next, you will create communication arrangement, pointing to the communication scenario and communication system.

1. Choose Communication Arrangements, then choose New.

   

2. Choose your communication scenario, Z_OUTBOUND_RFC_###_CSCEN. This name is also entered automatically for the communication arrangement. You can accept this default.

   
   

3. Choose the communication system you created, Z_OUTBOUND_RFC_CSYS_###.
   The other details, e.g. Communication User, RFC Outbound Service, and RFC Function Module are entered automatically.

4. Check the connection.

1. In ABAP Development Tools (ADT), in Project Explorer, open your ABAP Environment instance.
   For more information, see Set Up SAP BTP, ABAP Environment and create Your First Console Application.

2. In the project, create a new ABAP package.

3. Create a new ABAP class: Choose File > New > Other… > ABAP Class.

4. Enter the following for your class, then choose Next.

   • Name: ZCL_SYSTEM_INFO_RFC_###
   • Description for your class, e.g. Test RFC BTP to on-premise
   • Interface: if_oo_adt_classrun. This enables you to run the class in the console.

5. Create or assign a transport request.

First, you need to create the types and variables that specify your remote connection information.

Since the structure rfcsi is not a released object in SAP BTP, ABAP Environment, or in S/4HANA, Cloud edition, you need to create appropriate types for the variable lv_result. To generate these types for other remote function modules, use the transaction ACO_PROXY.

For readability and reuse, you will create these in an interface.

1. Select your package and choose New > Other ABAP Object > ABAP Interface from the context menu.

2. Enter the following and choose Next.

• Name: ZIF_TYPES_FOR_SYSTEM_INFO
• Description: Types for RFC_GET_SYSTEM_INFO

1. Choose the transport request, then choose Finish.

2. Add the following to the interface:

   ABAP

   Copy

     types:
       RFCPROTO TYPE C LENGTH 000003 .
     types:
       RFCCHARTYP TYPE C LENGTH 000004   .
     types:
       RFCINTTYP TYPE C LENGTH 000003   .
     types:
       RFCFLOTYP TYPE C LENGTH 000003   .
     types:
       RFCDEST TYPE C LENGTH 000032   .
     types:
       RFCCHAR8 TYPE C LENGTH 000008  .
     types:
       SYSYSID TYPE C LENGTH 000008  .
     types:
       RFCDBHOST TYPE C LENGTH 000032  .
     types:
       SYDBSYS TYPE C LENGTH 000010  .
     types:
       SYSAPRL TYPE C LENGTH 000004  .
     types:
       RFCMACH TYPE C LENGTH 000005  .
     types:
       SYOPSYS TYPE C LENGTH 000010  .
     types:
       RFCTZONE TYPE C LENGTH 000006  .
     types:
       SYDAYST TYPE C LENGTH 000001  .
     types:
       RFCIPADDR TYPE C LENGTH 000015  .
     types:
       SYKERNRL TYPE C LENGTH 000004  .
     types:
       SYHOST TYPE C LENGTH 000032  .
     types:
       RFCSI_RESV TYPE C LENGTH 000012  .
     types:
       RFCIPV6ADDR TYPE C LENGTH 000045  .
     types:
       BEGIN OF RFCSI                         ,
             RFCPROTO                       TYPE RFCPROTO                      ,
             RFCCHARTYP                     TYPE RFCCHARTYP                    ,
             RFCINTTYP                      TYPE RFCINTTYP                     ,
             RFCFLOTYP                      TYPE RFCFLOTYP                     ,
             RFCDEST                        TYPE RFCDEST                       ,
             RFCHOST                        TYPE RFCCHAR8                      ,
             RFCSYSID                       TYPE SYSYSID                       ,
             RFCDATABS                      TYPE SYSYSID                       ,
             RFCDBHOST                      TYPE RFCDBHOST                     ,
             RFCDBSYS                       TYPE SYDBSYS                       ,
             RFCSAPRL                       TYPE SYSAPRL                       ,
             RFCMACH                        TYPE RFCMACH                       ,
             RFCOPSYS                       TYPE SYOPSYS                       ,
             RFCTZONE                       TYPE RFCTZONE                      ,
             RFCDAYST                       TYPE SYDAYST                       ,
             RFCIPADDR                      TYPE RFCIPADDR                     ,
             RFCKERNRL                      TYPE SYKERNRL                      ,
             RFCHOST2                       TYPE SYHOST                        ,
             RFCSI_RESV                     TYPE RFCSI_RESV                    ,
             RFCIPV6ADDR                    TYPE RFCIPV6ADDR                   ,
       END OF RFCSI                           .
   
   

3. Format, save, and activate ( Sh+F1, Ctrl + Save, Ctrl + F3) your interface.

In the class implementation, in the method if_oo_adt_classrun~main, add the following variables.

```ABAP
DATA(lo_destination) = cl_rfc_destination_provider=>create_by_comm_arrangement(

    comm_scenario          = 'Z_OUTBOUND_RFC_###_CSCEN'   " Communication scenario
    service_id             = 'Z_OUTBOUND_RFC_###_SRFC'    " Outbound service

                      ).

DATA(lv_destination) = lo_destination->get_destination_name( ).

DATA lv_result type ZIF_TYPES_FOR_SYSTEM_INFO=>rfcsi.
DATA msg TYPE c LENGTH 255.

```

CALL function 'RFC_GET_SYSTEM_INFO'
destination lv_destination
  IMPORTING
    RFCSI_EXPORT      = lv_result.

Output the result of the RFC call to the ABAP Console

out->write( lv_result ).

Wrap the whole method in an exception using TRY…CATCH.

catch cx_root into data(lx_root).
  out->write( lx_root->get_text( ) ).
endtry.

1. Go back to your RFC class.

   In the method implementation for if_oo_adt_classrun~main, add a DATA statement (before you call the function):

   ABAP

   Copy

   
   DATA msg TYPE c LENGTH 255.
   
   

2. Now, in the function call for RFC_GET_SYSTEM_INFO, remove the period (.) after the IMPORTING parameter and add the following exception parameters to the function call RFC_GET_SYSTEM_INFO:

   ABAP

   Copy

   
   EXCEPTIONS
     system_failure        = 1 MESSAGE msg
     communication_failure = 2 MESSAGE msg
   OTHERS                    = 3.
   
   

3. Now evaluate sy-subrc by changing out->write( lv_result ). to include the following CASE...ENDCASE statement:

   ABAP

   Copy

   
   CASE sy-subrc.
      WHEN 0.
        out->write( lv_result ).
      WHEN 1.
        out->write( | EXCEPTION SYSTEM_FAILURE | && msg ).
      WHEN 2.
        out->write( | EXCEPTION COMMUNICATION_FAILURE | && msg ).
      WHEN 3.
        out->write( | EXCEPTION OTHERS | ).
   ENDCASE.
   
   

Your code should look roughly like this:

CLASS ZCL_SYSTEM_INFO_RFC_### DEFINITION
  public
  final
  create public .

public section.
  interfaces if_oo_adt_classrun.

protected section.
private section.
ENDCLASS.

CLASS ZCL_SYSTEM_INFO_RFC_### IMPLEMENTATION.
  METHOD IF_OO_ADT_CLASSRUN~MAIN.
    TRY.
        DATA(lo_destination) = cl_rfc_destination_provider=>create_by_comm_arrangement(

            comm_scenario          = 'Z_OUTBOUND_RFC_###_CSCEN'   " Communication scenario
            service_id             = 'Z_OUTBOUND_RFC_###_SRFC'    " Outbound service
            comm_system_id         = 'Z_OUTBOUND_RFC_CSYS_###'        " Communication system

        ).

        DATA(lv_destination) = lo_destination->get_destination_name( ).

        DATA lv_result TYPE ZIF_TYPES_FOR_SYSTEM_INFO=>RFCSI.
        DATA msg TYPE c LENGTH 255.

        CALL FUNCTION 'RFC_GET_SYSTEM_INFO'
          DESTINATION lv_destination
          IMPORTING
            rfcsi_export          = lv_result
          EXCEPTIONS
            system_failure        = 1 MESSAGE msg
            communication_failure = 2 MESSAGE msg
            OTHERS                = 3.

        CASE sy-subrc.
          WHEN 0.
            out->write( lv_result ).
          WHEN 1.
            out->write( | EXCEPTION SYSTEM_FAILURE | && msg ).
          WHEN 2.
            out->write( | EXCEPTION COMMUNICATION_FAILURE | && msg ).
          WHEN 3.
            out->write( | EXCEPTION OTHERS | ).
        ENDCASE.

      CATCH cx_root INTO DATA(lx_root).
        out->write( lx_root->get_text( ) ).
    ENDTRY.
    
  ENDMETHOD.

ENDCLASS.

1. Save and activate the class, using Ctrl+S, Ctrl+F3.

2. Run the class by choosing F9. The ABAP Console output should look roughly like this:

3. 

For information on ACO_PROXY, see:

• SAP Help Portal: RFC: Generating Static Proxies