convert dataset to json format

unit writedatasetJSONFormat_helper;

{$mode objfpc}{$H+}

interface

uses
  Classes,
  SysUtils,
  DB,
  SQLDB,
  jsonscanner,
  jsonparser,
  fpsimplejsonexport;

type
  TQueryDataToJSON = class helper for TSQLQuery
  private
  public
    function WriteJSONFormat : string;
  end;

implementation

function TQueryDataToJSON.WriteJSONFormat: string;
var
  LStream: TStringStream;
  LJSONExp: TSimpleJSONExporter;
  LParser : TJSONParser;
  memText : string;
begin
  LStream  := TStringStream.Create('');
  LJSONExp := TSimpleJSONExporter.Create(nil);
  with LJSONExp do
  begin
    FormatSettings.DateFormat := 'YYYY-MM-DD';
    FormatSettings.DateTimeFormat := 'YYYY-MM-DD hh:mm:ss';
    FormatSettings.DecimalSeparator := '.';
    FormatSettings.IndentSize:= 5;
    FormatSettings.ColumnFormat := cfObject;
    FormatSettings.RowFormat := rfArray;
    FileName := 'ConvertJSON';
  end;
  //
  try
    try
      LJSONExp.Dataset := Self;
      LJSONExp.ExportToStream(LStream);
    except
      on Exception do
      begin
        FreeAndNil(LJSONExp);
      end;
    end;

  finally
    memText := StringReplace(LStream.DataString, ';', ',', [rfReplaceAll]);
    memText := concat(LeftStr(memText, Length(memText) - 6),']');
    LParser:=TJSONParser.Create(memText, [joUTF8]);
    Result := LParser.Parse.FormatJSON([], 2);
  end;

end;

end.