An asynchronous handler returns data immediately and is usually tasked
with launching a process that can be lengthy. As mentioned previously, HttpHandlers have a
Table 3-1. Built-in ASP.NET Handlers
Handler Description
ASP.NET service handler Default HttpHandler for all ASP.NET service (.asmx) pages
ASP.NET page handler Default HttpHandler for all ASP.NET (.aspx) pages
88 CHAPTER 3 ?– ASP.NET S TATE MANAGEMENT
simple implementation compared to writing an ISAPI extension library. After writing and
compiling code to implement an HttpHandler, deployment is a matter of registering the handler
in the application??™s web.config file.
The single drawback when you compare HttpHandlers to ISAPI extensions is that you cannot
use HttpModules and HttpHandlers outside of ASP.NET in this manner.
ASP.NET and Server-Side State Management
Server-side state in ASP.NET consists of the familiar Application and Session objects, which
store application and user state data in a collection.
In general, data stored in Application variables tends to be like constants, shared by application
users and unchanging. Application variables are usually set in the global.asax file. Session
variables are user-connection specific and quite convenient for maintaining state throughout
an application.
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