internal Message GetSelectDatabaseCommand(int targetDatabase, Message message)
{
if (targetDatabase < 0)
{
return(null);
}
if (targetDatabase != currentDatabase)
{
var serverEndpoint = Bridge.ServerEndPoint;
int available = serverEndpoint.Databases;
if (!serverEndpoint.HasDatabases) // only db0 is available on cluster/twemproxy
{
if (targetDatabase != 0)
{ // should never see this, since the API doesn't allow it; thus not too worried about ExceptionFactory
throw new RedisCommandException("Multiple databases are not supported on this server; cannot switch to database: " + targetDatabase);
}
return(null);
}
if (message.Command == RedisCommand.SELECT)
{
// this could come from an EVAL/EVALSHA inside a transaction, for example; we'll accept it
Bridge.Trace("Switching database: " + targetDatabase);
currentDatabase = targetDatabase;
return(null);
}
if (TransactionActive)
{// should never see this, since the API doesn't allow it; thus not too worried about ExceptionFactory
throw new RedisCommandException("Multiple databases inside a transaction are not currently supported: " + targetDatabase);
}
if (available != 0 && targetDatabase >= available) // we positively know it is out of range
{
throw ExceptionFactory.DatabaseOutfRange(Multiplexer.IncludeDetailInExceptions, targetDatabase, message, serverEndpoint);
}
Bridge.Trace("Switching database: " + targetDatabase);
currentDatabase = targetDatabase;
return(GetSelectDatabaseCommand(targetDatabase));
}
return(null);
}