Using Spark To Transform template files or strings.cs

public abstract class RuleContextView : AbstractSparkView
{
	public IRuleContext Context { get; set; }

	public override string ToString()
	{
		return Context.ToString();
	}
}

public interface ITemplateTransformer
{
	string TransformFromTemplate(string templateName, IRuleContext ruleContext);
	string TransformFromString(string templateContents, IRuleContext ruleContext);
}

public class TemplateTransformer : ITemplateTransformer
{
	private readonly EmailSettings _emailSettings;

	public TemplateTransformer(EmailSettings emailSettings)
	{
		_emailSettings = emailSettings;
	}

	private static ISparkSettings getSparkSettings()
	{
		return (SparkSectionHandler) ConfigurationManager.GetSection("spark");
	}

	public string TransformFromTemplate(string templateName, IRuleContext ruleContext)
	{
		return generateFromView(ruleContext, engine =>
		{
			var viewFolder = new FileSystemViewFolder(_emailSettings.EmailTemplatePath);
			engine.ViewFolder = viewFolder;
			var sparkViewDescriptor = new SparkViewDescriptor().AddTemplate(templateName);

			var view = (RuleContextView)engine.CreateInstance(sparkViewDescriptor);

			return view;
		});
	}

	public string TransformFromString(string templateContents, IRuleContext ruleContext)
	{
		return generateFromView(ruleContext, engine =>
		{
			var templateName = templateContents.GetMD5Hash();
			var viewFolder = new InMemoryViewFolder
			                 {
			                 	{templateName, templateContents}
			                 };

			engine.ViewFolder = viewFolder;
			var sparkViewDescriptor = new SparkViewDescriptor().AddTemplate(templateName);

			var view = (RuleContextView)engine.CreateInstance(sparkViewDescriptor);

			return view;
		});
	}

	private static string generateFromView(IRuleContext ruleContext, Func<SparkViewEngine, RuleContextView> viewFactoryFunction)
	{
		var sparkViewEngine = new SparkViewEngine(getSparkSettings());

		var sparkView = viewFactoryFunction(sparkViewEngine);

		sparkView.Context = ruleContext;

		string output;
		using (var writer = new StringWriter())
		{
			try
			{
				sparkView.RenderView(writer);
			}
			finally
			{
				sparkViewEngine.ReleaseInstance(sparkView);
			}
			output = writer.ToString();
		}

		return output;
	}
}