@app.route('/dowload/<my_vars>/<filename>', methods=['GET'])
def dowload(filename = None, my_vars=None):
    data = filename.split('@')[0]
    file_name = filename.split('@')[1]
    if my_vars == 'radio_usr':
        return send_from_directory('report/usr/%s'%(data), file_name, as_attachment=True)
    else:
        with open(os.path.join('report/logs/%s'%(data), file_name), 'r', encoding='cp1251') as f:
            file = f.readlines()
        return render_template('simpl.html', file=file)

 file_name = filename.split('@')[1]
IndexError: list index out of range

 return file

 01.01.2017@1_042204#06_07_00.log

 try:
  file_name = filename.split('@')[1]
except IndexError:
  print(filename)
  raise