RFC: Get Data from an On-Premise System Using a Custom Entity

First, you create the class that implements the data retrieval logic.

1. In ADT, open your ABAP package and choose New > Class.

   

2. Enter the following, then choose Next:

   • Name: zcl_product_via_rfc_###
   • Description: Read product data via RFC
   • Interfaces: if_rap_query_provider

3. Choose the transport request, then choose Finish.

The signature of the method IF_RAP_QUERY_PROVIDER~SELECT contains the import parameter io_request. This parameter represents the OData query options that are delegated from the UI and used as input for the SELECT method. Whenever the OData client requests data, the query implementation class must return the data that matches the request, or throw an exception if the request cannot be fulfilled. Later in this tutorial, you will implement the SELECT method of the interface.

1. Now choose New > Other… > Core Data Services > Data Definition.

2. Enter a name and description:

   • zce_product_###
   • Read product data via RFC
   • Referenced Object: Leave blank

3. Choose the transport request, then choose Next. Do not choose Finish, yet!

4. Choose Define Custom Entity with Parameters, then choose Finish. Ignore the errors for now.

   

Add the following annotation to the view (immediately after the ‘@EndUserText.label’ annotation), pointing to the class you have just created - NOTE: Use upper case!

@ObjectModel.query.implementedBy: 'ABAP:ZCL_PRODUCT_VIA_RFC_###'

1. Remove the following lines from the view:

   CDS Copy

   
   with parameters parameter_name : parameter_type {
    key key_element_name : key_element_type;
    element_name : element_type;
   
   }

2. Add the header information to the view, after the @QueryImplementedBy annotation. For more information on the UI Annotations used here, see SAP Help Portal: SAP BTP: ABAP RESTful PM: Defining UI Annotations

   CDS Copy

   
   @UI: {
     headerInfo: {
     typeName: 'Product',
     typeNamePlural: 'Products'
     }
   }

3. Add the fields and their associations.

   CDS Copy

   
   define root custom entity zce_product_###
   {
   
         @UI.facet     : [
           {
             id        :       'Product',
             purpose   :  #STANDARD,
             type      :     #IDENTIFICATION_REFERENCE,
             label     :    'Product',
             position  : 10 }
         ]
         // DDL source code for custom entity for BAPI_EPM_PRODUCT_HEADER
   
         @UI           : {
         lineItem      : [{position: 10, importance: #HIGH}],
         identification: [{position: 10}],
         selectionField: [{position: 10}]
         }
     key product_id     : abap.char( 10 );
         TypeCode      : abap.char( 2 );
         @UI           : {
         lineItem      : [{position: 20, importance: #HIGH}],
         identification: [{position: 20}],
         selectionField: [{position: 20}]
         }
         Category      : abap.char( 40 );
         @UI           : {
         lineItem      : [{position: 30, importance: #HIGH}],
         identification: [{position: 30}]
         }
         Name          : abap.char( 255 );
         @UI           : {
         identification: [{position: 40}]
         }
         Description   : abap.char( 255 );
         SupplierId    : abap.char( 10 );
         SupplierName  : abap.char( 80 );
         TaxTarifCode  : abap.int1;
         @Semantics.unitOfMeasure: true
         MeasureUnit   : abap.unit( 3 );
         @Semantics.quantity.unitOfMeasure: 'WeightUnit'
         WeightMeasure : abap.quan( 13, 3 );
         @Semantics.unitOfMeasure: true
         WeightUnit    : abap.unit( 3 );
         @UI           : {
         lineItem      : [{position: 50, importance: #HIGH}],
         identification: [{position: 50}]
         }
         Price         : abap.dec( 23, 4 );
         @Semantics.currency_code: true
         currency_code  : abap.cuky( 5 );
         @Semantics.quantity.unitOfMeasure: 'DimUnit'
         Width         : abap.quan( 13, 3 );
         @Semantics.quantity.unitOfMeasure: 'DimUnit'
         Depth         : abap.quan( 13, 3 );
         @Semantics.quantity.unitOfMeasure: 'DimUnit'
         Height        : abap.quan( 13, 3 );
         @Semantics.unitOfMeasure: true
         DimUnit       : abap.unit( 3 );
         ProductPicUrl : abap.char( 255 );
   
   }

   Show all 62 lines Show less

You will now implement the data retrieval logic in the class.

Go back to the class.

1. First, in the CLASS...DEFINITION , PUBLIC SECTION., define a type for the variable maxrows. You will need this later to call the BAPI:

   ABAP Copy

   
       TYPES:
           BEGIN OF bapi_epm_max_rows,
               bapimaxrow TYPE bapimaxrow,
           END OF bapi_epm_max_rows.

2. Now, in the CLASS...IMPLEMENTATION, define an local internal table, which you will fill by retrieving the data from the back end. The type of the local variable is the CDS View that you just created. Add the following code to the if_rap_query_provider~select method.

   ABAP Copy

   DATA lt_product TYPE STANDARD TABLE OF zce_product_###.

3. Create a variable, lv_abap_trial. If you are using the full version of SAP BTP, ABAP Environment, set it to false, otherwise true.

   ABAP Copy

   
   DATA(lv_abap_trial) = abap_false.  

If you are working in the trial version, omit this step.

If you are working in the full version of ABAP Environment: Define the connection as follows, replacing ### with your initials or group number. Ignore any warnings for now. Wrap this in a TRY. ...CATCH... ENDTRY.

IMPORTANT: Always specify the authentication mode using the interface if_a4c_cp_service. Never hard-code your password in the class.

```ABAP

IF lv_abap_trial = abap_false.

  TRY.
    DATA(lo_destination) = cl_rfc_destination_provider=>create_by_comm_arrangement(
             comm_scenario          = 'Z_OUTBOUND_RFC_000_CSCEN'   " Communication scenario
             service_id             = 'Z_OUTBOUND_RFC_000_SRFC'    " Outbound service

                         ).

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

  CATCH cx_rfc_dest_provider_error INTO DATA(lx_dest).
  ENDTRY.

ENDIF.

```

1. Check whether data is being requested.

   ABAP Copy

   
   IF io_request->is_data_requested( ).
   
   ENDIF.

2. Now, in the CLASS...IMPLEMENTATION., add an IF... ELSE. ... ENDIF. block. If you are using the trial version, fill the internal table lt_product with the mock data. If not, call the BAPI.

   ABAP Copy

   
   DATA ls_maxrows TYPE bapi_epm_max_rows.
   DATA(lv_skip) = io_request->get_paging( )->get_offset(  ).
   DATA(lv_top) = io_request->get_paging( )->get_page_size(  ).
   ls_maxrows-bapimaxrow = lv_skip + lv_top.
   
    IF lv_abap_trial = abap_true.
         lt_product = VALUE #( ( product_id = 'HT-1000' name = 'Notebook' )
                               ( product_id = 'HT-1001' name = 'Notebook' )
                               ( product_id = 'HT-1002' name = 'Notebook' )
                               ( product_id = 'HT-1003' name = 'Notebook' )
                               ( product_id = 'HT-1004' name = 'Notebook' )
                               ( product_id = 'HT-1005' name = 'Notebook' )
                         ).
   
   
   ELSE.
   "Call BAPI                      
   CALL FUNCTION 'BAPI_EPM_PRODUCT_GET_LIST'
      DESTINATION lv_destination
      EXPORTING
            max_rows   = ls_maxrows
      TABLES
            headerdata = lt_product.
   
   ENDIF.

1. Set the total number of records requested.

   ABAP Copy

   
   IF io_request->is_total_numb_of_rec_requested( ).
   io_response->set_total_number_of_records( lines( lt_product ) ).
   ENDIF.

2. Output the data in the internal table.

   ABAP Copy

   
   io_response->set_data( lt_product ).

Wrap the whole data retrieval logic call in a second TRY. ..CATCH...ENDTRY block.

```ABAP

TRY.
...
  CATCH cx_rfc_dest_provider_error INTO DATA(lx_dest).
ENDTRY.

```

Now that you have defined your view, and retrieved the data using the class, you can expose the view as a Business Service. A Business Service consists of a Service Definition and a Service Binding.

You use a Service Definition to define which data is to be exposed (with the required granularity) as a Business Service.

You then use the Service Binding to bind a service definition to a client-server communication protocol such as OData. This allows you to provide several bindings for the same definition, e.g. to expose the service to a UI, and to an A2X provider.

Start with the Service Definition:

1. From your package, select your custom entity, zce_product_###, then choose New > Service Definition from the context menu, then choose Next.

   

2. Enter the following and choose Next:

   • Name: ZCE_PRODUCT_###
   • Description: Expose product data via RFC
   • Source Type: Definition
   • Referenced Object: ZCE_PRODUCT_###

   

3. Choose the transport request; choose Next.

4. Use the selected template; choose Finish. The name of your custom entity is inserted automatically.

   

5. Optional: For readability, add an alias, such as Products:

   CDS Copy

   expose zce_product_### as Products;

6. Save and activate ( Ctrl+S, Ctrl+F3 ) the service definition.

1. Select your service definition, then choose Service Binding from the context menu, then choose Next.

2. Enter the following, then choose Next:

   • Name = ZUI_CE_PRODUCT_###
   • Description = Bind product data via RFC
   • Binding Type = ODATA V2 (UI…)
   • Service Definition = ZCE_PRODUCT_###

   

3. Choose the transport request; choose Finish.

The service binding automatically references the service definition and thus the exposed custom entity.

The names of the service definition and binding comply with the Naming Conventions for Development Objects in SAP Help Portal.

1. In the editor that appears, choose Activate.

   

2. Then choose Publish. You can now see the Service URL and Entity Set.

   

3. You can open the Service Document (XML) in your browser, by choosing Service URL.

   

4. In the browser, you can also see the Metadata Document of the Business Service by adding the suffix $metadata to the URL: sap/opu/odata/sap/Z_BIND_PRODUCT_TEST_001/$metadata.

   

1. Select the entity set and choose Preview.

   

2. Log in using your ABAP Environment user and password; the Fiori Elements preview appears.

3. Display the data by choosing Go.

   

If the data does not display (and you are using the licensed version), check that the BAPI is retrieving the data, as follows:

1. Open the class you created in Test the Connection to the Remote System.

2. Replace the type ty_bapi_epm_product_header:

   ABAP Copy

   
   DATA lt_product TYPE STANDARD TABLE OF  ty_bapi_epm_product_header.
   DATA ls_product TYPE ty_bapi_epm_product_header.

with the type of your custom entity:

```ABAP

DATA lt_product TYPE STANDARD TABLE OF zce_product_via_rfc_###.
DATA ls_product TYPE zce_product_via_rfc_###.

```

The console output should look like this:

More Information

• SAP Help Portal: BAPI

• SAP Help Portal: Using a CDS Custom Entity to Define the Data Model for an OData Service

• SAP Help Portal: Service Definition

• Implement a custom entity in the ABAP RESTful Programming Model using RFC - includes handling a single record, filtering, and ordering

• Insert test data into tables in SAP BTP, ABAP Environment

• Call a remote OData service from the trial version of SAP BTP ABAP environment

• Find out more about SAP Business Technology Platform ABAP Environment on SAP Community: SAP Business Technology Platform ABAP Environment