Long running operation on website

What if I have website with a button. User clicks on the button and starts a long running process. After a few hours (or minutes) user update webpage and see results. What is the best (and any other) way to implement long running operation on websi开发者_开发技巧te?

From the user experience point of view I suggest you implement the job like you would implement order handling in an online shop.

When the user starts the job he should be able to track the state of the job. Is the job complete? Did the job fail? What is the progress of the job? He should probably also be able to cancel the job and perhaps modify properties of the job. You could implement an notification mechanism using e-mail or an SMS and the user should be able to control that.

By using JavaScript/AJAX you can provide a more interactive user experience where the job status web page is automatically refreshed at regular intervals in the background without forcing the user to refresh his browser.

The user should be able to leave his computer and later connect to the website from another computer and still be able to get information about pending and completed jobs. This requires some form of user login.

I suggest that you separate the job handling code from the website code. You could expose the job handling user a web service or another similar technology. The website should query the service and display the results providing a user interface on top of the job service.

How long? If it's really going to take hours, you don't want that code running in the web server. Have the server spawn an external process or start a service or something along that line, and put the long running code in there.

You could have that code put status updates somewhere (like in the database) as it runs, and the website can check that when the user comes back to see how it's doing.

I suggest you read up on Threading in asp.Net. For website performance, time consuming processes can be put on a different thread.

A different approach is executing the task with AJAX. This way, you can present the user interface to the user, and start an asynchronous process which handles the request.