Monday, March 26, 2012

Handlers vs. Modules

Modules are units of code that have registered for one or more pipeline events. They perform authentication, authorization, logging, etc. There is one task that is reserved for a special module, known as a handler. The handler’s unique job is to retrieve the resource that is requested in the URL. All resources served by IIS are mapped to a handler in configuration. If the configuration mapping does not exist, requests for the resource will receive a 404 HTTP status. In addition to the configuration mapping, which takes place before the pipeline begins, the handler mapping can be changed during request execution in the MAP_REQUEST_HANDLER event. This allows scenarios such as URL rewriting to work. Handlers are notified, or executed, in the EXECUTE_REQUEST_HANDLER step. (Note that only the mapped handler is notified, as you would expect.)

1 comment:

  1. How ASP .NET different from ASP?- Scripting is separated from the HTML, Code is compiled as a DLL, these DLLs can be executed on the server.
    What is smart navigation?- The cursor position is maintained when the page gets refreshed due to the server side validation and the page gets refreshed.
    What is view state?- The web is stateless. But in ASP.NET, the state of a page is maintained in the in the page itself automatically. How? The values are encrypted and saved in hidden controls. this is done automatically by the ASP.NET. This can be switched off / on for a single control
    How do you validate the controls in an ASP .NET page?- Using special validation controls that are meant for this. We have Range Validator, Email Validator.
    Can the validation be done in the server side? Or this can be done only in the Client side?- Client side is done by default. Server side validation is also possible. We can switch off the client side and server side can be done.
    How to manage pagination in a page?- Client side is done by default. Server side validation is also possible. We can switch off the client side and server side can be done.
    What’ is the sequence in which ASP.NET events are processed?- Following is the sequence in which the events occur :-
    1. Page_Init.
    2. Page_Load.
    3. Control events
    4. Page_Unload event.
    Page_init event only occurs when first time the page is started, but Page_Load occurs in subsequent request of the page.
    What is an application object?-Application object ca be n used in situation where we want data to be shared across users globally.
    What’s the difference between Cache object and application object?-The main difference between the Cache and Application objects is that the Cache object provides cache-specific features, such as dependencies and expiration policies.
    How can get access to cache object?-The Cache object is defined in the System.Web.Caching namespace. You can get a reference to the Cache object by using the Cache property of the HttpContext class in the System.Web namespace or by using the Cache property of the Page object.