SAP Gateway SEGW DPC_EXT CRUD Methods Generator for OData in ABAP

" Project ZPM_ORDERS, entity type Order, entity set OrderSet
" In SE24 or SEGW use Redefine; in ADT add the lines below.
CLASS ZCL_ZPM_ORDERS_DPC_EXT DEFINITION
  PUBLIC
  INHERITING FROM ZCL_ZPM_ORDERS_DPC
  CREATE PUBLIC.

  PROTECTED SECTION.
    METHODS OrderSet_get_entityset REDEFINITION.
    METHODS OrderSet_get_entity REDEFINITION.
    METHODS OrderSet_create_entity REDEFINITION.
    METHODS OrderSet_update_entity REDEFINITION.
    METHODS OrderSet_delete_entity REDEFINITION.
ENDCLASS.

METHOD OrderSet_get_entityset.
  DATA lr_key TYPE RANGE OF AUFK-AUFNR.
  DATA lt_entityset LIKE et_entityset.
  DATA lv_max TYPE i.

  " Filter on the key: technical context returns ABAP (internal) property names
  DATA(lt_filter) = io_tech_request_context->get_filter( )->get_filter_select_options( ).
  READ TABLE lt_filter INTO DATA(ls_filter) WITH KEY property = 'AUFNR'.
  IF sy-subrc = 0.
    lr_key = CORRESPONDING #( ls_filter-select_options ).
  ENDIF.

  " Read only what the page needs: $top plus $skip rows (0 means no limit)
  IF is_paging-top > 0.
    lv_max = is_paging-top + is_paging-skip.
  ENDIF.

  SELECT aufnr, auart, ktext, werks, erdat
    FROM AUFK
    WHERE AUFNR IN @lr_key
    ORDER BY AUFNR
    INTO CORRESPONDING FIELDS OF TABLE @lt_entityset
    UP TO @lv_max ROWS.

  IF is_paging-skip > 0.
    DELETE lt_entityset FROM 1 TO is_paging-skip.
  ENDIF.

  IF io_tech_request_context->has_inlinecount( ) = abap_true.
    SELECT COUNT(*) FROM AUFK
      WHERE AUFNR IN @lr_key
      INTO @DATA(lv_count).
    es_response_context-inlinecount = lv_count.
  ENDIF.

  et_entityset = lt_entityset.
ENDMETHOD.

METHOD OrderSet_get_entity.
  DATA lv_key TYPE AUFK-AUFNR.

  READ TABLE it_key_tab INTO DATA(ls_key) WITH KEY name = 'Aufnr'.
  IF sy-subrc <> 0.
    RAISE EXCEPTION TYPE /iwbep/cx_mgw_busi_exception
      EXPORTING
        textid  = /iwbep/cx_mgw_busi_exception=>business_error
        message = 'Key Aufnr missing in request'.
  ENDIF.

  " Add leading zeros, for example order 4711 becomes 000000004711
  CALL FUNCTION 'CONVERSION_EXIT_ALPHA_INPUT'
    EXPORTING
      input  = ls_key-value
    IMPORTING
      output = lv_key.

  SELECT SINGLE aufnr, auart, ktext, werks, erdat
    FROM AUFK
    WHERE AUFNR = @lv_key
    INTO CORRESPONDING FIELDS OF @er_entity.
  IF sy-subrc <> 0.
    RAISE EXCEPTION TYPE /iwbep/cx_mgw_busi_exception
      EXPORTING
        textid  = /iwbep/cx_mgw_busi_exception=>business_error
        message = 'Entry not found'.
  ENDIF.
ENDMETHOD.

METHOD OrderSet_create_entity.
  DATA ls_entity TYPE ZCL_ZPM_ORDERS_MPC=>TS_ORDER.

  io_data_provider->read_entry_data( IMPORTING es_data = ls_entity ).

  IF ls_entity-ktext IS INITIAL.
    RAISE EXCEPTION TYPE /iwbep/cx_mgw_busi_exception
      EXPORTING
        textid  = /iwbep/cx_mgw_busi_exception=>business_error
        message = 'ktext is required'.
  ENDIF.

  " Create the business object with a released BAPI here and map
  " its RETURN messages to the exception above. Never INSERT into
  " standard tables such as AUFK directly.

  er_entity = ls_entity.
ENDMETHOD.

METHOD OrderSet_update_entity.
  DATA ls_entity TYPE ZCL_ZPM_ORDERS_MPC=>TS_ORDER.

  READ TABLE it_key_tab INTO DATA(ls_key) WITH KEY name = 'Aufnr'.
  IF sy-subrc <> 0.
    RAISE EXCEPTION TYPE /iwbep/cx_mgw_busi_exception
      EXPORTING
        textid  = /iwbep/cx_mgw_busi_exception=>business_error
        message = 'Key Aufnr missing in request'.
  ENDIF.

  io_data_provider->read_entry_data( IMPORTING es_data = ls_entity ).

  " The key in the URL wins over any key in the payload
  CALL FUNCTION 'CONVERSION_EXIT_ALPHA_INPUT'
    EXPORTING
      input  = ls_key-value
    IMPORTING
      output = ls_entity-AUFNR.

  " Change the business object with a released BAPI here.

  er_entity = ls_entity.
ENDMETHOD.

METHOD OrderSet_delete_entity.
  DATA lv_key TYPE AUFK-AUFNR.

  READ TABLE it_key_tab INTO DATA(ls_key) WITH KEY name = 'Aufnr'.
  IF sy-subrc <> 0.
    RAISE EXCEPTION TYPE /iwbep/cx_mgw_busi_exception
      EXPORTING
        textid  = /iwbep/cx_mgw_busi_exception=>business_error
        message = 'Key Aufnr missing in request'.
  ENDIF.

  CALL FUNCTION 'CONVERSION_EXIT_ALPHA_INPUT'
    EXPORTING
      input  = ls_key-value
    IMPORTING
      output = lv_key.

  SELECT SINGLE @abap_true FROM AUFK
    WHERE AUFNR = @lv_key
    INTO @DATA(lv_exists).
  IF sy-subrc <> 0.
    RAISE EXCEPTION TYPE /iwbep/cx_mgw_busi_exception
      EXPORTING
        textid  = /iwbep/cx_mgw_busi_exception=>business_error
        message = 'Entry not found'.
  ENDIF.

  " Set the deletion flag or status with a released BAPI here.
ENDMETHOD.

GET  /sap/opu/odata/sap/ZPM_ORDERS_SRV/OrderSet?$filter=Aufnr eq '4711'&$top=20&$skip=0&$inlinecount=allpages
GET  /sap/opu/odata/sap/ZPM_ORDERS_SRV/OrderSet('000000004711')

For POST, PUT and DELETE first send a GET with header
  X-CSRF-Token: Fetch
then copy the returned token into the X-CSRF-Token header of the write request.