How to cache roster list with memcache?

Hi

How to cache roster list with memcache?

I can pay some service fee if you can provide the code．

Thanks.

odbc_queries.erl:

get_roster(LServer, Username) ->
ejabberd_odbc:sql_query(
LServer,
["select username, jid, nick, subscription, ask, "
"askmessage, server, subscribe, type from rosterusers "
"where username='", Username, "'"]).