NHibernate Glimpse Plugin - full source

hs-blog-NHibernateGlimpsePlugin.txt

http://www.headspring.com/2011/07/creating-a-glimpse-plugin-to-log-sql-generated-by-nhibernate

The following code is all that's required to implement a Glimpse plugin that renders the SQL generated by NHibernate. A full blog post describing this is at the link above.

1. Create a custom Log4Net appender:
-----------------------------------

public class NHibernateQueryAppender : AppenderSkeleton
{
	protected override void Append(LoggingEvent loggingEvent)
	{
		//This part is trivial - you can collect the RenderedMessage (the SQL statement)
		//several ways. SqlLogger is just a wrapper over the HttpContext.Items collection
		SqlLogger.AddSql(loggingEvent.RenderedMessage);
	}
}


3. Configure Log4Net in your web.config:
---------------------------------------

<log4net>
	<appender name="GlimpseAppender" type="Headspring.Data.NHibernateQueryAppender, Headspring" />
	<logger name="NHibernate.SQL">
		<level value="DEBUG"/>
		<appender-ref ref="GlimpseAppender" />
	</logger>
</log4net>


3. Create the Glimpse Plugin:
----------------------------

[Glimpse.Core.Extensibility.GlimpsePluginAttribute()]
public class NHGlimpsePlugin : IGlimpsePlugin
{
	public object GetData(HttpContextBase context)
	{
		var data = new List<object[]> { new[] { "Key", "Value" } };

		data.Add(new object[] { "*count*", SqlLogger.Count });

		foreach (var sqlString in SqlLogger.All())
		{
			data.Add(new object[] { "*sql*", sqlString });
		}

		return data;
	}

	public void SetupInit() { }

	public string Name { get { return "NHibernate"; } }
}


4. The SqlLogger implementation:
-------------------------------

//Again, this is just a mechanism for the logger to log the SQL to, and the Glimpse plugin to retrieve the SQL from.

public static class SqlLogger
{
	public static void AddSql(string sql)
	{
		SqlStatements.Add(sql);
	}

	public static IEnumerable<string> All()
	{
		return SqlStatements;
	}

	public static int Count { get { return SqlStatements.Count; } }

	private static IList<string> SqlStatements
	{
		get 
		{ 
			var statements = HttpContext.Current.Items["sql"] as List<string>;
			if (statements == null)
			{
				statements = new List<string>();
				HttpContext.Current.Items["sql"] = statements;
			}

			return statements;
		}
	}
}