Call a Remote Function Module From SAP Business Technology Platform (BTP), ABAP Environment

First, you need to connect your ABAP on-premise system to a Cloud Foundry subaccount 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. Choose Add Subaccount:

   Field Name	Value
   Region	Your region. You can find this in SAP BTP cockpit (see screenshot below) - e.g. here, Europe (Frankfurt) - AWS
   Subaccount	Cloud Foundry Subaccount ID. You can find this by choosing your subaccount in SAP BTP cockpit and choosing the information (i) icon. (see screenshot below)
   Display Name	(Subaccount) Display Name. You can find this in by choosing your subaccount in SAP BTP cockpit (see screenshot below)
   Subaccount User
   Password
   Location ID	Optional here. However, it is mandatory if you want to connect several Cloud Connectors to your subaccount. This can be any text, e.g. XXX for your initials or group number as here

   

Your configuration should now look like this. Note down the Location ID, here XXX. You will need it later.

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

   

2. In the Mapping Virtual to Internal System pane, choose Add (+).

   

3. Enter the following values, and choose Save.

   Field Name	Value
   Backend Type	ABAP
   Protocol	RFC
   	Without Load Balancing
   Application Server	IP address of the on-premise server, e.g. of NPL
   Instance Number	00
   Virtual Host	e.g. nplhost. 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.
   Virt. Inst. No.	00
   Principal Type	None
   Description	Optional
   Check Internal Host	Ticked

   

The mapping should now look something like this. Check that the status = Reachable. If not, check that you chose the correct port, or whether an internal firewall is preventing communication:

Now, still in the Cloud to On-Premise > Access Control tab, enter the resource you need, RFC_SYSTEM_INFO.

1. Add the resource RFC_SYSTEM_INFO by choosing the Protocol = RFC, then choosing +.

   

2. Enter the name of the RFC, e.g. RFC_SYSTEM_INFO. Alternatively, add RFC as a Prefix. Then choose Save

   

3. Add BAPIs to the list of resources by choosing + again. (You will need this BAPI in a later tutorial.)

4. Enter the name BAPI_EPM as a Prefix, then choose Save.

5. The list of resources should now look roughly like this.

   

In the SAP BTP cockpit of your Cloud Foundry subaccount, choose Cloud Connectors:

The location ID points to the correct SAP Cloud Connector (located in the on-Premise system); The virtual host points to the on-Premise connection mapped in SAP Cloud Connector.

You will now create a destination in the ABAP Environment. This must be created at subaccount (not Space) level.

1. In the SAP BTP cockpit of your Cloud Foundry subaccount, choose Destinations, then choose New Destinations.

   

2. Enter the following values:

   Field Name	Value
   Name	e.g. NPL_JP as here
   Type	RFC
   Description	Can be anything, here NPL
   Location ID	same as in step 1, e.g. XXX
   User	Your user for the on-premise system, e.g. DEVELOPER
   Password	Your password

3. Add the following additional properties and values, by choosing New Property:

   Field Name	Value
   jco.client.ashost	Virtual hostname of your on-premise ABAP System, defined in SAP Cloud Connector, e.g. <nplhost>
   jco.client.client	<Your ABAP System client, e.g. 001
   jco.client.sysnr	<Your ABAP System number>, e.g. 00

   

   .
   

   

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

2. Enter a name and description. The name should be in the form ZCL_...RFC_XXX. Replace XXX with your group number or initials.

3. Create or assign a transport request.

1. Implement the interface by adding this statement to the public section:

   interfaces if_oo_adt_classrun.

   This allows you to test your class by displaying the output in the ABAP Console.

2. In the implementation section, add the METHOD and ENDMETHOD statements:

   METHOD IF_OO_ADT_CLASSRUN~MAIN.
ENDMETHOD.

Create the data types that specify your remote connection information, replacing the i_name with your the name of the specific RFC destination, which you created in SAP BTP cockpit (in step 5 of this tutorial).

```ABAP
DATA(lo_destination) = cl_rfc_destination_provider=>CREATE_BY_CLOUD_DESTINATION(
                        i_name                  = 'NPL_JP'

                       ).

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

DATA lv_result type c length 200.

```

CALL function 'RFC_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.

Your code should look roughly like this:

CLASS ZCL_A4C_RFC_XXX DEFINITION
  public
  final
  create public .

public section.
  interfaces if_oo_adt_classrun.
protected section.
private section.
ENDCLASS.

CLASS ZCL_A4C_RFC_XXX IMPLEMENTATION.
  METHOD IF_OO_ADT_CLASSRUN~MAIN.
    TRY.
      DATA(lo_destination) = cl_rfc_destination_provider=>CREATE_BY_CLOUD_DESTINATION(
                              i_name                  = 'NPL_JP'
                             ).

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

      DATA lv_result type c length 200.

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

        out->write( lv_result ).
    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. Some system information, such as the hostname, the System ID ( <SID> ), and the IP address should be displayed.

1. Go back to your RFC class. Remove the period (.) after the IMPORTING parameter and add the following exception parameters to the function call RFC_SYSTEM_INFO:

   ABAP

   Copy

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

2. Now evaluate sy-subrc by adding 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.