DataSetToJSON

unit FMX.DataSetToJSON;

interface
 uses
  FireDAC.Comp.Client,Data.DB;

  function DataSetToJSON(DataSet:TDataSet):String;
  function JSONToDataSet(JSONTEXT:String):TFDMemTable;


implementation
uses System.Rtti,System.JSON;


function DataSetToJSON(DataSet:TDataSet):String;
var
  I:integer;
  JSONObject,FieldJSONObject:TJSONObject;
  JSONArray:TJSONArray;
begin
  Result:='';
      JSONObject:=TJSONObject.ParseJSONValue('{}') as TJSONObject;
       try
              JSONObject.AddPair('Fields',TJSONArray.Create);
              JSONArray:=JSONObject.GetValue('Fields') as TJSONArray;
              for I := 0 to DataSet.FieldDefs.Count   -1 do
              begin
                          FieldJSONObject:=TJSONObject.Create ;
                          FieldJSONObject.AddPair  ('FieldName',DataSet.FieldDefs[i].Name );
                          FieldJSONObject.AddPair('DataType',TRttiEnumerationType.GetName<TFieldType>(DataSet.FieldDefs[i].DataType));
                          FieldJSONObject.AddPair('DataSize',TJSONNumber.Create(DataSet.FieldDefs[i].Size));
                          JSONArray.Add(FieldJSONObject) ;
              end;
              DataSet.First ;
              JSONObject.AddPair('DATAS',TJSONArray.Create);
              JSONArray:=JSONObject.GetValue('DATAS') as TJSONArray;
              while not DataSet.Eof  do
              begin
                  FieldJSONObject:=TJSONObject.Create ;
                  for I := 0 to DataSet.FieldDefs.Count   -1 do
                  FieldJSONObject.AddPair(DataSet.FieldDefs[i].Name,DataSet.Fields[i].AsString);
                  JSONArray.Add(FieldJSONObject) ;
                  DataSet.Next ;
              end;
              Result :=  JSONObject.ToJSON ;
       finally
           JSONObject.Free ;
       end;
end;


function JSONToDataSet(JSONTEXT:String):TFDMemTable;
var
  I,R:integer;
  JSONObject,FieldJSONObject:TJSONObject;
  JSONArray:TJSONArray;
  DataName,DataType:String;
  FieldType:TFieldType;
  FieldSize:integer;
begin
  Result:=TFDMemTable.Create(nil);
  if JSONTEXT='' then Exit;
       JSONObject:=TJSONObject.ParseJSONValue(JSONTEXT)  as TJSONObject;
       try
              JSONArray:=JSONObject.GetValue('Fields') as TJSONArray;
              for I := 0 to JSONArray.size  -1 do
              begin
                  Result.FieldDefs.Add(((JSONArray.Get(i) as TJSONObject).GetValue('FieldName') as TJSONString).Value,
                  TRttiEnumerationType.GetValue<TFieldType>(((JSONArray.Get(i) as TJSONObject).GetValue('DataType')  as TJSONString).Value),
                  ((JSONArray.Get(i) as TJSONObject).GetValue('DataSize') as TJSONNumber).AsInt64);
              end;
              Result.CreateDataSet ;
              JSONArray:=JSONObject.GetValue('DATAS') as TJSONArray;
              for I := 0 to JSONArray.size  -1 do
              begin
                  Result.Append ;
                  for R := 0 to Result.FieldDefs.Count -1  do
                  begin
                      FieldJSONObject:=(JSONArray.Get(i) as TJSONObject);
                      if FieldJSONObject=nil then continue;

                      try
                      Result.FieldByName(Result.FieldDefs[R].Name).Value :=
                      (FieldJSONObject.GetValue(Result.FieldDefs[R].Name) as TJSONString).Value ;

                      Except
                      end;
                  end;
                  Result.Post ;
              end;
       finally
           JSONObject.Free ;
       end;
end;
end.