Question

I have one difficult situation.

As we know NH SessionFactory is a singleton in our app.

“Heavyweight, thread-safe, and you only should ever have one per
database”.

And SessionFactory is created from Configuration().BuildSessionFactory() where Configuration() is my fluently configured database.

Here is the poblem.
I need to use different users for my connection string in an MVC app. This is needed to connect to the database by different users. When connection is ok, then I use NH to manipulate domain mapped objects.

Question here is how to pass different users to Configuration and use this SessionFactory in case when we need create Configuration first of all? Creating the SessionFactory again is a wrong way, right?

And this becomes more harder because I use Windsor container to register all objects before my MVC app’s run.

Answer 1

It sounds like you are wanting to provide a different connection string for different users of your application.

NHibernate has a feature in which you can provide your own DriverConnectionProvider which will allow you to ultimately be able to create custom connection strings on the fly by overriding the GetConnection() method.

Example:

class DynamicConnectionProvider : DriverConnectionProvider
{
    public override IDbConnection GetConnection()
    {
        IDbConnection connection = Driver.CreateConnection();

        try
        {
            connection.ConnectionString = // Add your logic for dynamically creating a connection string

            connection.Open();
        }
        catch ( Exception e )
        {
            connection.Dispose();

            throw;
        }

        return connection;
    }
}

You can also take a look at the following links for examples:

• https://stackoverflow.com/a/2927967/670028
• http://nhforge.org/blogs/nhibernate/archive/2008/09/18/extending-nhibernate-s-driverconnectionprovider.aspx

And yes, creating duplicate SessionFactories would be quite costly to your applications memory usage, would complicate your applications architecture, and is really unnecessary as there are other options such as the one I listed above.