protected virtual Task DbGc()
{
const string sql = "delete SheepJaxMessages where CreatedUtcTime < dateadd(minute, -10, GetUtcDate())";
return(_connectionFactory().WithinTransaction(tx =>
TplHelper.Using(new SqlCommand(sql, tx.Connection, tx), cmd =>
cmd.ExecuteNonQueryAsync().Success(_ => tx.Commit())
)
).Catch(_logger));
}
public virtual Task Consumed(CommandMessage last)
{
var msg = last as SqlCommandMessage;
if (msg == null)
{
return(TplHelper.Empty);
}
const string sql = "delete SheepJaxMessages where ClientId=@clientId and timestamp<@timestamp";
var dbTask = _connectionFactory().WithinTransaction(tx =>
TplHelper.Using(new SqlCommand(sql, tx.Connection, tx)
{
Parameters =
{
new SqlParameter("clientId", msg.ClientId),
new SqlParameter("timestamp", msg.Timestamp)
}
}
, cmd => cmd.ExecuteNonQueryAsync().Finally(_ => tx.Commit())
)
).Catch(_logger);
using (_cacheLock.BeginUpgradeableReadLock())
{
var node = _cache.Last;
while (node != null && node.Value != last)
{
node = node.Previous;
}
using (_cacheLock.BeginWriteLock())
{
while (node != null)
{
var previousNode = node.Previous;
while (previousNode != null && previousNode.Value.ClientId != node.Value.ClientId)
{
previousNode = previousNode.Previous;
}
node.List.Remove(node);
node = previousNode;
}
}
}
return(dbTask);
}
private void SendMessage(Guid clientId, string msg)
{
const string sql = "insert into SheepJaxMessages (ClientId, Message) values (@clientId, @message)";
Task.Factory.StartNew(delegate
{
_connectionFactory().WithinTransaction(tx =>
TplHelper.Using(new SqlCommand(sql, tx.Connection, tx)
{
Parameters =
{
new SqlParameter("clientId", clientId),
new SqlParameter("message", msg)
}
},
cmd => cmd.ExecuteNonQueryAsync().Finally(t => tx.Commit())
)
);
}).Catch(_logger);
}
protected virtual Task PollDb(IObserver <SqlCommandMessage> observer)
{
const string sql = "select ClientId, Message, CreatedUtcTime, Timestamp from SheepJaxMessages where CreatedUtcTime > dateadd(minute, -10, GetUtcDate())";
return(_connectionFactory().WithinTransaction(tx =>
TplHelper.Using(new SqlCommand(sql, tx.Connection, tx), cmd =>
{
if (_lastTimestamp != null)
{
cmd.CommandText += " and timestamp > @lastTimestamp";
cmd.Parameters.Add(new SqlParameter("lastTimestamp", _lastTimestamp));
}
cmd.CommandText += " order by timestamp asc";
return cmd.ExecuteReaderAsync()
.Select(reader =>
{
using (reader)
while (reader.Read())
{
var timestamp = _lastTimestamp = new byte[8];
reader.GetBytes(3, 0, timestamp, 0, 8);
var msg = new SqlCommandMessage
{
ClientId = reader.GetGuid(0),
Message = reader.GetString(1),
CreatedUtcTime = reader.GetDateTime(2),
Timestamp = timestamp
};
using (_cacheLock.BeginWriteLock())
{
_cache.AddLast(msg);
observer.OnNext(msg);
}
}
});
})
).Catch(_logger));
}
