gistfile1.erl

 is_primary_for_doc(BKey) ->    
     {ok, CHBin} = riak_core_ring_manager:get_chash_bin(),
     DocIdx = riak_core_util:chash_key(BKey),
     Itr = chashbin:iterator(DocIdx, CHBin),
     MyNode = node(),
     case chashbin:itr_value(Itr) of
         {_Idx, Node} when Node == MyNode -> true;
         {_Idx, _Node} -> false
     end.

 copy_to_cache(Object) ->
     {ok, Client} = riak:local_client(),
     Bucket = << "cached_events" >>,
     Key = riak_object:key(Object),
     case is_primary_for_doc({Bucket, Key}) of
 	true ->
 	    NewObj = riak_object:new( Bucket,
 				      Key,
 				      riak_object:get_value(Object) ),
 	    riak_client:put(NewObj, 0, 0, Client),
 	    Object;
 	false ->
 	    Object
     end.