NHibernate
The object-relational mapper for .NET
Note: this was orginally posted on my own blog
Ahh, i'm finally able to use NHibernate again at work, so expect more NHibernate related posts in the future :)
Today i needed a way to add some functionality when NHibernate opens a database connection, and again when NHibernate closes the connection. When the connection is opened, i need to setup some context on the connection for auditing purposes and it needs to be cleared again when the connection is closed. So i started searching on how to plug this into NHibernate. As usual, this was trivially easy to do.
All you need to do is create a type that implements the IConnectionProvider interface. In my case, i only needed to add a bit of behavior so i could just derive from NHibernate's standard DriverConnectionProvider class and add the stuff i needed at the right time:
public class AuditingConnectionProvider : NHibernate.Connection.DriverConnectionProvider
{
public override IDbConnection GetConnection()
{
IDbConnection connection = base.GetConnection();
SetContextInfo(connection);
return connection;
}
public override void CloseConnection(IDbConnection connection)
{
ClearContextInfo(connection);
base.CloseConnection(connection);
}
private void SetContextInfo(IDbConnection connection)
{
// ...
}
private void ClearContextInfo(IDbConnection connection)
{
// ...
}
}
Pretty simple huh? All you have to do now is to configure NHibernate to use this new ConnectionProvider in your hibernate.cfg.xml file:
<property name="connection.provider">My.Assembly.AuditingConnectionProvider, My.Assembly</property>
Was that easy or what? If only all frameworks were extensible in such an easy manner ;)