Fast ASP.NET Websites

Chapter 8. ETags

This chapter covers

• ETags: what they are and why you should change them
• How browsers validate cache components
• Removing ETags in ASP.NET Web Forms and ASP.NET applications

In chapter 4, we examined and implemented HTTP Expires headers in an ASP.NET application. These HTTP headers tell the browser it can store certain components in its cache for a set amount of time, thereby reducing page load times because the browser doesn’t need to retrieve these components from the server. In order to ensure the components are still valid, the browser makes a small validation request. In this chapter, you’re going to investigate the ways the browser validates its cache components and what you can do to eliminate unnecessary HTTP requests. ...