detail:
1. add utils.BytesToString function instead of string() convert bytes to string.
2. use bytes.NewReader instead of strings.NewReader(string(sb)).
3. use w.Body.Bytes() instead of []byte(w.Body.String()).
1. Mongo dial add 5 seconds connection timeout.
2. Redis uses connection pool mode.
3. Redis pool new connection have 10 seconds write timeout and read timeout and connection timeout.