[{"param1":"1","user":"name1","pass":"pass1"}]

procedure TForm1.IdHTTPServer1CommandGet(AContext: TIdContext;
  ARequestInfo: TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo);
var
  strStream: TStringStream;
  s: string;
begin
  if ARequestInfo.CommandType = hcPOST then
  begin
    strStream:= TStringStream.Create('',CP_UTF8);
    strStream.LoadFromStream(ARequestInfo.PostStream);
    s := strStream.Datastring;
    TThread.Queue(nil,
        procedure
        begin
          Memo1.Lines.Add(s);
        end
      );
    AResponseInfo.ResponseNo := 200;
  end
end;

procedure TForm1.IdHTTPServer1CommandGet(AContext: TIdContext;
  ARequestInfo: TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo);
var
  strStream: TStringStream;
  s: string;
  json: TJSONObject;

begin
  if ARequestInfo.CommandType = hcPOST then
  begin
    strStream:= TStringStream.Create('',CP_UTF8);
    strStream.LoadFromStream(ARequestInfo.PostStream);
    s := strStream.Datastring;
    json:= TJSONObject.Create;
    json:= TJSONObject.ParseJSONValue(s) as TJSONObject;
    if Assigned(json) then
      TThread.Queue(nil,
        procedure
        begin
          Memo1.Lines.Add(json.GetValue<string>('user'));
        end
      );
    AResponseInfo.ResponseNo := 200;
  end
end;

{$APPTYPE CONSOLE}
 
uses
  DBXJSON,
  System.SysUtils;
 
Const
StrJson =
  '['+
  '{"EventType":49,"Code":"234","EventDate":"20050202", "Result":1},'+
  '{"EventType":48,"Code":"0120","EventDate":"20130201", "Group":"g1"}'+
  ']';
 
 
procedure ParseJson;
var
  LJsonArr   : TJSONArray;
  LJsonValue : TJSONValue;
  LItem     : TJSONValue;
begin
   LJsonArr    := TJSONObject.ParseJSONValue(TEncoding.ASCII.GetBytes(StrJson),0) as TJSONArray;
   for LJsonValue in LJsonArr do
   begin
      for LItem in TJSONArray(LJsonValue) do
        Writeln(Format('%s : %s',[TJSONPair(LItem).JsonString.Value, TJSONPair(LItem).JsonValue.Value]));
     Writeln;
   end;
end;
 
begin
  try
    ParseJson;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
  Readln;
end.