Friday, September 30, 2011

ASP.NET MVC: Performance tips

Although there are a lot of different ways to optimize your ASP.NET MVC web applications, some are cheaper then others. Here are some very simple tips that still can make a significant difference:
Run in Release mode
Always make sure that your application is compiled in Release mode and that your web.config file is configured with <compilation debug="false" />. Use the web.config transformations feature to automatically change this value in release mode.
Use only the View Engines that you need
As you probably know the MVC framework supports multiple view engines. This means that each time MVC is trying to find a view it’s searching through all these view engines. In MVC 3 two view engines are registered by default (WebForms and Razor). So if you use only one view engine, remove the ones you are not using:
protected void Application_Start() 
	ViewEngines.Engines.Add(new RazorViewEngine()); 
Use the CachedDataAnnotationsModelMetadataProvider from ASP.NET MVC Futures
In the ASP.NET MVC 3 Futures you can find a little gem called the CachedDataAnnotationsModelMetadataProvider. For using this provider, just open global.asax file and add the following line in the Application_Start method, 

ModelMetadataProviders.Current = new CachedDataAnnotationsModelMetadataProvider();

Avoid passing null models to views
Don’t pass in a null model to a view that uses strongly-typed html helpers (such as Html.TextBoxFor). Strongly-typed html helpers such as Html.TextBoxFor(m => m.Name) will try to emit the value of the model using the provided expression. However when something along the expression chain is null a NullReferenceException will be thrown when the expression gets evaluated. MVC’s expression evaluator catches the exception but on a page with multiple such html helpers the cost of the exception adds up. You can avoid that cost by always passing an empty instance of the model to the view:

public ActionResult Insert() 
	return View(new Product()); 

Uninstall URL Rewrite if you don’t use it
When performing URL generation (for example via a method like Html.ActionLink) in some cases MVC checks to see if the currently requested URL has been rewritten by the URL Rewrite module. If that is the case the result is processed so that it correctly matches the URL requested by the client. The act of checking if a URL has been rewritten has a non-trivial cost (because it involves checking server variables). ASP.NET MVC 3 checks to see if URL Rewrite is turned off and can cache that fact thus avoiding the need to inspect server variables for each request. If URL Rewrite is turned on MVC will have to check server variables even if no rewriting happened for a particular request so if you are not using URL Rewrite you should turn it off.

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