Offline mode in ASP.NET Web Application

Question

I want to build a web application (SaaS) that can work both in Online and Offline modes. The user needs limited features in case he is offline and full feature access when he becomes online again. I thought of the following options:

1. Make the user download a local server such as Cassini and devise an architecture to allow online and offline modes in the web application. I am not sure how it will be done but I believe all the commands will be routed through this local server. The local server will then decide whether it accesses the local resources or the server. Making a user install application on his system will defeat the whole idea behind SaaS.

2. Use Google Gears - I just checked how Google Docs work in offline mode. It installs Google Gears on the user's system which was pretty neat and fast and copies all the files locally. A link is provided to access the offline version. This seems like a good option to me as it integrates a local server, relational datastore and a worker pool in itself but is Google Gears mature enough to be used in production?

Has anyone worked/working on such an application. Ideas welcome.

EDIT @1: I am not very familiar with Silverlight and whether it can be used in such a scenario.

EDIT @2: The following link mentions that SilverLight can be used to develop Offline applications Offline SilverLight I am looking for expert comments from people who have used SilverLight in their development. Can user work offline? Can user re-open the same webpage after closing the browser window?

Answer 1

Seems to me that "web application" and "offline mode" are a bit contradictory.

I have seen some examples of Silverlight being used in such a way however. And, at one time, I implemented a WinForms smart client application that worked in such a way. These days, though, I would definately look into Silverlight.

Answer 2

If you choose to let users install an app on their computer, I would consider developing a Windows Forms app instead of a web app, basically because this seem like a more logical solution. If you deploy the app using ClickOnce it is remarkably easy to keep the clients up to date.

From a user's point of view, I think that Gears is mature. I use in it Gmail, Google Calendar and Google Docs, pretty much without any problems. I don't know about the developer tools. It might help to use Google Clusure Library since it has methods specific for Google Gears.

Depending on the web browser that you need to support, you could also take a look at HTML 5. O'Reilly's online book Building iPhone Apps with HTML, CSS, and JavaScript has a chapter about making a web app work in offline mode.