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Create RFC Functions

This section shows how to create, register and use RFC server functions.

Register the RFC Server Function

  1. Initialize an RFCServer object. Provide the gateway host, the gateway service and the program ID to register on the SAP gateway. The program ID must be available as a registered destination in SAP, see Set Up an RFC Destination.
  2. Register an RFCServerFunction object using RegisteredFunctions.Add. An RFCServer object can hold more than one RFCServerFunction object.
  3. Add Imports and Exports. They are handled the same way as when calling RFC functions as a client.
  4. When an ABAP program calls the function, the event IncomingCall is triggered.
    When using C#, the event call-back must be defined in a separate line of code.
  5. Start the server using Start.

Note

If the RFC destination is set to Unicode (SAP transaction code SM59), the property IsUnicode of the RFCServer object must be set to true.

In the following sample applications a simple RFC server function is created that allows ABAP programs to add numbers.

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using ERPConnect; 

static void Main(string[] args) 
{ 
   RFCServer s = new RFCServer();
   s.GatewayHost = "sap-erp-as05.example.com"; 
   s.GatewayService = "sapgw11"; 
   s.ProgramID = "ERPTEST"; 

   s.IncomingCall+=new ERPConnect.RFCServer.OnIncomingCall(s_IncomingCall); 

   RFCServerFunction f = s.RegisteredFunctions.Add("Z_ADD"); 

   f.Imports.Add("NUMBER1",RFCTYPE.INT); 
   f.Imports.Add("NUMBER2",RFCTYPE.INT); 
   f.Exports.Add("RES",RFCTYPE.INT); 

   s.Start(); 

   Console.Write( "Server is running. Press any key to exit."); 
   Console.ReadLine(); 
}

Two input parameters (NUMBER1 and NUMBER2) are added in a new function (Z_ADD). The result (RES) is passed back to the calling ABAP program, see Call RFC Server Functions in ABAP. 

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using ERPConnect; 

static void Main(string[] args)
{

    static RFCServer s = new RFCServer();
    s.GatewayHost = "SAPServer";
    s.GatewayService = "sapgw00";
    s.ProgramID = "ERPConnectTEST";

    s.IncomingCall += new RFCServer.OnIncomingCall(s_IncomingCall);

    RFCServerFunction f = s.RegisteredFunctions.Add("Z_ADD_2");

    f.Exports.Add("RES", RFCTYPE.INT);

    RFCTable numbertable = f.Tables.Add("NUMBERS");
    numbertable.Columns.Add("NUMB", 10, 0, RFCTYPE.NUM); 

    s.Start();

    Console.WriteLine("Press Enter to quit");
    Console.ReadLine();
}

A table (NUMBERS) with a column (NUMB) is added to a table collection using Add(). The result (RES) is passed back to the calling ABAP program, see Call RFC Server Functions in ABAP. 

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using ERPConnect; 

static void Main(string[] args)
{
    static RFCServer s = new RFCServer();
    s.GatewayHost = "hamlet";
    s.GatewayService = "sapgw11";
    s.ProgramID = "ERPTEST";

    s.IncomingCall += new RFCServer.OnIncomingCall(s_IncomingCall);

    RFCServerFunction f = s.RegisteredFunctions.Add("Z_ADD_3");

    RFCTableColumnCollection Columns = new RFCTableColumnCollection ();
    Columns.Add("NUMB", 10, 0, RFCTYPE.NUM);
    Columns.Add("NUMB2", 10, 0, RFCTYPE.NUM);

    f.Imports.Add("NUMBERS",Columns );
    f.Exports.Add("RES", RFCTYPE.INT);

    s.Start();

    Console.WriteLine("Press Enter to quit");
    Console.ReadLine();
}

A structure (NUMBERS) with 2 columns (NUMB1 and NUMB2) is added to a column collection via RFCTableColumnCollection(). The result (RES) is passed back to the calling ABAP program, see Call RFC Server Functions in ABAP. 

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using ERPConnect; 

static void Main(string[] args)
{

    static RFCServer s = new RFCServer();
    s.GatewayHost = "hamlet";
    s.GatewayService = "sapgw11";
    s.ProgramID = "ERPTEST";

    s.IncomingCall += new RFCServer.OnIncomingCall(s_IncomingCall);

    RFCServerFunction f = s.RegisteredFunctions.Add("Z_ADD_4");

    RFCTableColumnCollection Columns = new RFCTableColumnCollection ();
    Columns.Add("NUMB1", 10, 0, RFCTYPE.NUM);
    Columns.Add("NUMB2", 10, 0, RFCTYPE.NUM);

    RFCTableColumnCollection EXColumns = new RFCTableColumnCollection();
    EXColumns.Add("NUMB1", 10, 0, RFCTYPE.NUM);
    EXColumns.Add("NUMB2", 10, 0, RFCTYPE.NUM);

    f.Imports.Add("NUMBERS",Columns );
    f.Exports.Add("EXNUMBERS", EXColumns);

    s.Start();

    Console.WriteLine("Press Enter to quit");
    Console.ReadLine();
}

Two structures (NUMBERS and EXNUMBERS) with 2 columns (NUMB1 and NUMB2) are added to column collections via RFCTableColumnCollection(). One structure (NUMBERS) is used for import and the other (EXNUMBERS) is passed back to the calling ABAP program, see Call RFC Server Functions in ABAP.

Handle Incoming Calls

The following code shows how the IncomingCall event is handled:

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private static void s_IncomingCall(RFCServer Sender, RFCServerFunction CalledFunction) 
{ 
   if (CalledFunction.FunctionName=="Z_ADD") 
   { 
      Int32 i1 = (Int32)CalledFunction.Imports["NUMBER1"].ParamValue; 
      Int32 i2 = (Int32)CalledFunction.Imports["NUMBER2"].ParamValue; 
      Int32 res = i1 + i2; 
      CalledFunction.Exports["RES"].ParamValue = res; 
      Console.WriteLine("Incoming Call"); 
   } 
   Else 
      throw new ERPConnect.ERPException("Function unknown"); 
}

The result is returned in the scalar export parameter RES.

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static void s_IncomingCall(RFCServer Sender, RFCServerFunction CalledFunction)
{
    Console.WriteLine("Incoming call!!");

    Int32 res = 0;

    foreach (RFCStructure row in CalledFunction.Tables["NUMBERS"].Rows)
        res += Convert.ToInt32(row["NUMB"]);

    CalledFunction.Exports["RES"].ParamValue = res;
}

Use the object hierarchy to iterate through the rows and add the values. The result is returned in the scalar export parameter RES.

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static void s_IncomingCall(RFCServer Sender, RFCServerFunction CalledFunction)
{
    Console.WriteLine("Incoming call!!");

    Int32 res = 0;
    RFCStructure numberstruc = CalledFunction.Imports["NUMBERS"].ToStructure();

    Int32 i1 = Convert.ToInt32(numberstruc["NUMB"].ToString());
    Int32 i2 = Convert.ToInt32(numberstruc["NUMB2"].ToString());

    res = i1 + i2;

    CalledFunction.Exports["RES"].ParamValue = res;
}

The result is returned in the scalar export parameter RES.

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static void s_IncomingCall(RFCServer Sender, RFCServerFunction CalledFunction)
{
    Console.WriteLine("Incoming call!!");

    RFCTableColumnCollection EXColumns = new RFCTableColumnCollection();
    EXColumns.Add("NUMB1", 10, 0, RFCTYPE.NUM);
    EXColumns.Add("NUMB2", 10, 0, RFCTYPE.NUM);

    CalledFunction.Exports.Add("EXNUMBER", EXColumns);
    RFCStructure numberstruc = CalledFunction.Imports["NUMBERS"].ToStructure();

    Int32 i1 = Convert.ToInt32(numberstruc["NUMB1"].ToString());
    Int32 i2 = Convert.ToInt32(numberstruc["NUMB2"].ToString());

    RFCStructure EXnumbers = CalledFunction.Exports["EXNUMBERS"].ToStructure();
    EXnumbers["NUMB1"] = i1 + 1;
    EXnumbers["NUMB2"] = i2 + 98;
}

The values from the IMPORT collection (numberstruc) are set in variables. Then different values are added to them and are written back to the EXPORT collection (EXnumbers).

The import parameters are passed by the calling SAP system.
The export parameters are passed back to SAP.

Call RFC Server Functions in ABAP

The following ABAP code is used to call the new function Z_ADD in the remote destination ERPTEST.

REPORT z_add_test 

DATA result TYPE i.
CALL FUNCTION 'Z_ADD' DESTINATION 'ERPTEST' 
   EXPORTING 
      number1 = 26 
      number2 = 25 
   IMPORTING 
      res = result. 
   WRITE: / 'Result: ', result.

The two numbers 26 and 25 are passed, and the result 51 is passed back. 

REPORT  zaddtest2 

DATA res TYPE i.
DATA numbs LIKE zaddstruc OCCURS 0 WITH HEADER LINE.

numbs-numb = '1'.
APPEND numbs.
numbs-numb = '2'.
APPEND numbs.
numbs-numb = '3'.
APPEND numbs.

CALL FUNCTION 'Z_ADD_2' DESTINATION 'ERPConnectTEST'
  IMPORTING
    res     = res
  TABLES
    numbers = numbs.

WRITE: / 'Result: ', res.

The two numbers 1, 2 and 3 are passed, and the result 6 is passed back. 

REPORT  ZADDTEST3

DATA res TYPE i.
DATA numbs LIKE zaddstruc2.

numbs-numb1 = '1'.
numbs-numb2 = '2'.

CALL FUNCTION 'Z_ADD_3' DESTINATION 'ERPTEST'
  EXPORTING
    NUMBERS       = numbs
 IMPORTING
   RES           = res.

WRITE: / 'Result: ', res.

The two numbers 1 and 2 are passed, and the result 3 is passed back. 

REPORT  ZADDTEST4                               .
                            .
DATA numbs LIKE zaddstruc2.
DATA exnumbers like zaddstruc2.

numbs-numb1 = '1'.
numbs-numb2 = '2'.

CALL FUNCTION 'Z_ADD_4' DESTINATION 'ERPTEST'
  EXPORTING
    NUMBERS       = numbs
   IMPORTING
   EXNUMBERS      = exnumbers.

WRITE: / 'First result is (added 1): ', exnumbers-numb1 .
WRITE: / 'Second result is (added 98): ', exnumbers-numb2 .

The two numbers 1 and 2 are passed, and the results 2 and 100 are passed back.

Last update: January 2, 2024