ASP.NET

ASP.NET

ASP.NET is a Web application framework developed and marketed by Microsoft to allow programmers to build dynamic Web sites, Web applications and Web services. It was first released in January 2002 with version 1.0 of the .NET Framework, and is the successor to Microsoft's Active Server Pages ...

 HTTP Handlers are a new technique presented in ASP.NET that was not present in the "Classic" ASP

Active Server Pages

Active Server Pages , also known as Classic ASP or ASP Classic, was Microsoft's first server-side script engine for dynamically-generated Web pages. Initially released as an add-on to Internet Information Services via the Windows NT 4.0 Option Pack Active Server Pages (ASP), also known as Classic...

. HTTP Handlers are components that implement the System.Web.IHttpHandler interface. Unlike ASP.NET Pages they have no HTML-markup file, no events and other supporting. All they have is a code-file (written in any .NET-compatible language) that writes some data to the server HTTP response.

ASP.NET handlers have ".ashx" file extension (unlike pages, that have ".aspx" file extension).

Handlers are considered to be more lightweight object than pages. That's why they are used to serve dynamically-generated images, on-the-fly generated PDF

Portable Document Format

Portable Document Format is an open standard for document exchange. This file format, created by Adobe Systems in 1993, is used for representing documents in a manner independent of application software, hardware, and operating systems....

-files and similar content to the web browser

Web browser

A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

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External links

• IHttpHandlers at MSDN