ABAP Utility class for mapping JSON to ABAP data and vice versa - Rather use https://gist.github.com/mydoghasworms/4888a832e28491c3fe47

json_util.abap

* Rather use https://gist.github.com/mydoghasworms/4888a832e28491c3fe47
* The alternative is a better parser although it is not an emmitter)
*----------------------------------------------------------------------*
*       CLASS json_util DEFINITION
*----------------------------------------------------------------------*
class json_util definition.
  public section.
    class-methods:
      data_to_json importing data type any
                   returning value(json) type string,
      json_to_data importing json type string
                   changing data type any.
endclass.                    "json_util DEFINITION

*----------------------------------------------------------------------*
*       CLASS json_util IMPLEMENTATION
*----------------------------------------------------------------------*
class json_util implementation.
  method data_to_json.

    data: lr_desc type ref to cl_abap_typedescr.
    data: lr_elem type ref to cl_abap_elemdescr.
    data: lr_sdes type ref to cl_abap_structdescr.
    data: ls_comp type cl_abap_structdescr=>component.
    data: lt_comp type cl_abap_structdescr=>component_table.
    data: lv_json type string.
    data: lv_field type string.
    data: lv_value type text255.
    field-symbols: <field> type any.
    data: lt_x031l type dd_x031l_table.
    data: ls_x031l type x031l.
    data: ls_dfies type dfies.
    data: lv_meth(30) type c value 'GET_DDIC_FIELD'.
    data: lv_date type d.
    data: lv_date_c(10) type c.
    data: lv_time type t.
    data: lv_time_c(8) type c.
    data: lv_tabix type i.
    data: lv_index type i.
    data: lv_passed1st type boole_d.

    lr_desc = cl_abap_typedescr=>describe_by_data( data ).

    case lr_desc->type_kind.

      when cl_abap_typedescr=>typekind_struct1 or cl_abap_typedescr=>typekind_struct2.
        json = '{'.
* Use RTTI to discover structure members and process them individually
        lr_sdes ?= lr_desc.
        lt_comp = lr_sdes->get_components( ).
        loop at lt_comp into ls_comp.

          assign component ls_comp-name of structure data
            to <field>.
          if sy-subrc = 0 and <field> is not initial.

* For consecutive elements, add a comma separator after the previous value
            if lv_passed1st = 'X'.
              concatenate json ',' into json.
            endif.

            lv_json = data_to_json( data = <field> ).

            concatenate json ' "' ls_comp-name '": ' lv_json into json.

            lv_passed1st = 'X'.
          endif.

        endloop.
        concatenate json '}' into json.
      when cl_abap_typedescr=>typekind_table.
        data: ld_line type ref to data.
        field-symbols: <tab> type any table.
        field-symbols: <line> type any.
        assign data to <tab>.
        create data ld_line like line of <tab>.
        assign ld_line->* to <line>.

* Open array for table entries
        json = '['.

        loop at <tab> into <line>.
          lv_json = data_to_json( data = <line> ).
          concatenate json lv_json into json separated by space.
          at last.
            continue.
          endat.
* Separate consecutive values by commas
          concatenate json ',' into json.
        endloop.

* Close array for table entries
        concatenate json ']' into json separated by space.

      when cl_abap_typedescr=>typekind_dref.
* For data references, dereference the data and call method again
        field-symbols: <data> type any.
        assign data->* to <data>.
        if sy-subrc = 0.
          json = data_to_json( data = <data> ).
        else.
          json = '{}'. "Will produce empty JS object
        endif.
      when others.
* For elementary types, we merely return a text representation of the value
        json = data.
        condense json.

* Escape special characters
        replace all occurrences of '\'                                    in json with '\\'.
        replace all occurrences of '"'                                    in json with '\"'.
        replace all occurrences of cl_abap_char_utilities=>newline        in json with '\n'.
        replace all occurrences of cl_abap_char_utilities=>horizontal_tab in json with '\t'.
        replace all occurrences of cl_abap_char_utilities=>form_feed      in json with '\f'.
        replace all occurrences of cl_abap_char_utilities=>vertical_tab   in json with '\v'.
        replace all occurrences of cl_abap_char_utilities=>backspace      in json with '\b'.

* Numeric values do not need to be escaped
        if lr_desc->type_kind ne cl_abap_typedescr=>typekind_num and
           lr_desc->type_kind ne cl_abap_typedescr=>typekind_packed and
           lr_desc->type_kind ne cl_abap_typedescr=>typekind_float and
           lr_desc->type_kind ne cl_abap_typedescr=>typekind_int and
           lr_desc->type_kind ne cl_abap_typedescr=>typekind_int1 and
           lr_desc->type_kind ne cl_abap_typedescr=>typekind_int2.
          concatenate '"' json '"' into json.
        endif.

    endcase.

  endmethod.                    "data_to_json

  method json_to_data.
    data: lv_off type i.
    data: lv_len type i.
    data: lv_key type string.
    data: lv_value type string.
    data: lv_char type char1.    "Current chacater
    data: lv_pchar type char1.   "Previous character
    data: lv_instr type boole_d. "Indicator: cursor in string
    data: lv_level type i.       "Depth inside a block
    data: lv_table type boole_d.
    field-symbols: <fk> type string.
    field-symbols: <data> type any.
    field-symbols: <table> type any table.
    field-symbols: <sotab> type sorted table.
    field-symbols: <sttab> type standard table.
    field-symbols: <line> type any.
    data: ls_line type ref to data.
    data: lr_td type ref to cl_abap_typedescr.
    data: lr_ttd type ref to cl_abap_tabledescr.

* If the incoming json contains no '{}[]', we are dealing with
* a basic (scalar) value that is simply assigned to the data
* and then we return
    if json na '{}[]'.
* Replace escape characters (TODO: Check if there are more!)
      lv_value = json.
      replace all occurrences of '\n' in lv_value with cl_abap_char_utilities=>newline.
      replace all occurrences of '\t' in lv_value with cl_abap_char_utilities=>horizontal_tab.
      replace all occurrences of '\f' in lv_value with cl_abap_char_utilities=>form_feed.
      replace all occurrences of '\v' in lv_value with cl_abap_char_utilities=>vertical_tab.
      replace all occurrences of '\b' in lv_value with cl_abap_char_utilities=>backspace.
      replace all occurrences of '\\' in lv_value with '\'.
* TODO: Deal with specific data types, e.g. dates etc.
      data = lv_value.
      exit.
    endif.

    lv_len = strlen( json ).

* Check if we are dealing with a table
    lr_td = cl_abap_typedescr=>describe_by_data( data ).
    if lr_td->type_kind = cl_abap_typedescr=>typekind_table.
* This information is used later...
      lv_table = 'X'.
      assign data to <table>.
      create data ls_line like line of <table>.
      assign ls_line->* to <line>.
    else.
      lv_table = ' '.
    endif.

* Reset counters/flags
    lv_off = 0.
    lv_instr = ' '.
    lv_level = 0.
    assign lv_key to <fk>.

    while lv_off < lv_len.
      lv_char = json+lv_off(1).

**********************************************************************
* IN STRING
**********************************************************************
* Character is in a string delimited by double quotes
      if lv_instr = 'X'.
        if lv_char = '"'.
* Switch out of delimited character string
          if lv_pchar ne '\'.
            lv_instr = ' '.
          else.
            concatenate <fk> lv_char into <fk> respecting blanks.
          endif.
        else.
          concatenate <fk> lv_char into <fk> respecting blanks.
        endif.

**********************************************************************
* OUTSIDE STRING
**********************************************************************
* Character is not in a string delimited by double quotes
      else.

* On opening character, shift level up
        if lv_char ca '{['.
          add 1 to lv_level.
        endif.

* When the value is contained in a {}/[], the entire value must
* be passed to the next level of processing
        if lv_level > 1.
          concatenate <fk> lv_char into <fk> respecting blanks.
        else.
          if lv_char ca '[{'. "<- Chars ignored outside of str
          elseif lv_char = ':'.
            assign lv_value to <fk>.
* The key collected up to now is assigned to the data member
            translate lv_key to upper case.
            shift lv_key left deleting leading space.
            assign component lv_key of structure data to <data>.

* End of a key/value pair (we bump up against delimiter) - pass to next level
          elseif ( lv_char = ',' or lv_char = '}' ) and lv_table = space.

* Process collected value
            shift lv_value left deleting leading space.
            json_to_data( exporting json = lv_value changing data = <data> ).

* Clear key and value
            clear: lv_key, lv_value.

            assign lv_key to <fk>.

            clear: lv_key, lv_value.

* End of a key/value pair (we bump up against delimiter) - pass to next level
* But in table mode, we pass an instance of a row of the table, and afterward
* add it to the table
          elseif ( lv_char = ',' or lv_char = ']' ) and lv_table = 'X'.

* Process collected value
* Inside array in JSON, there are no keys, only list of values, the collected
* value is in lv_key
            shift lv_key left deleting leading space.
            json_to_data( exporting json = lv_key changing data = <line> ).

* On return: if dealing with table, add the record to the table
            lr_ttd ?= lr_td.
            if lr_ttd->table_kind = cl_abap_tabledescr=>tablekind_sorted
              or lr_ttd->table_kind = cl_abap_tabledescr=>tablekind_hashed.
              assign data to <sotab>.
              insert <line> into table <sotab>.
            else.
              assign data to <sttab>.
              append <line> to <sttab>.
            endif.
            clear <line>.

* Clear key and value
            clear: lv_key, lv_value.

            assign lv_key to <fk>.

            clear: lv_key, lv_value.

* Switch cursor into delimited string; consecutive characters
* are then treated as part of a key or value, even if they are
* special characters
          elseif lv_char = '"'.
            lv_instr = 'X'.

* Other chars processed as either key or value
          else.
            concatenate <fk> lv_char into <fk> respecting blanks.
          endif.

        endif.

* On closing character, shift level down again
        if lv_char ca '}]'.
          subtract 1 from lv_level.
        endif.

* END: Are we in string or out?
      endif.

      lv_pchar = lv_char.
      add 1 to lv_off.
    endwhile.
  endmethod.                    "json_to_data
endclass.                    "json_util IMPLEMENTATION

Hi,

if a structure includes another structure you need to insert code between line 48 and 49 to extract the components of each structure recursively and make sure that gt_comp has all fields like SE11 expands the .INCLUDE structures.

also if a numeric value is processed and has leading zeros I would suggest to call this FM like here (line #116):

() Numeric values do not need to be escaped
IF lo_desc->type_kind NE cl_abap_typedescr=>typekind_num AND
lo_desc->type_kind NE cl_abap_typedescr=>typekind_packed AND
lo_desc->type_kind NE cl_abap_typedescr=>typekind_float AND
lo_desc->type_kind NE cl_abap_typedescr=>typekind_int AND
lo_desc->type_kind NE cl_abap_typedescr=>typekind_int1 AND
lo_desc->type_kind NE cl_abap_typedescr=>typekind_int2.
CONCATENATE '"' rv_json '"' INTO rv_json.
ELSE.
() Eliminate leading zeros for numeric values
CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
EXPORTING
input = rv_json
IMPORTING
output = rv_json.
ENDIF.

Cheers,
Martin

hey please help me out i am new in abap .
How to get field from json format webervice into abap code.

hi i need to consume the rest web service through abap program... I have all the details for the WSDL URL or rest web service which is created in cake PHP .Now i need to send some data in structure through our abap code ... i stuck in this process please let me know the solution.. i will be very grateful to you guys ...thanks pallavi

Thank you very much for such simplicity. I'm dealing with an old SAP version (4.7). None of the actual implementations worked like that, due the syntax limitations.