Offline capability for web application RRS feed

  • Question

  • I have a web application which contains details about job vacancies and applicant postings.  Now this same application has to be made available to a central operator who will either connect to the web application or for some unavoidable situation if the connectivity to the web application cannot be made connect to an offline version of the application and make any updates, modifications to the content of the web application.  The operator can also apply for job postings on behlaf of other users.


    My question is, how do I develop this offline capability in situations where the connection to the web application cannot be made?  Are there any ready made tools which I can use for this?

    Wednesday, January 19, 2011 4:15 PM

All replies

  • Just look into ASP.NET 4.0 WITH SLIVERLIGHT

    Thursday, January 20, 2011 2:59 AM
  • Thursday, January 20, 2011 3:02 AM
  • Page not found error is coming for your recommeded URL




    Thursday, January 20, 2011 5:55 AM
  • I recently outlined the way such a silverlight application could work.

    The key thing to consider is whether this is almost always going to have connectivity and the disconnected aspect is a rarity or whether it's going to occur a lot.

    For rarely disconnected all you need to do is store the write part of the process in a repository and have a separate thread running to handle this.

    For often disconnected you need to copy all the core data to the pc and quite frankly by the time you allow for all that you might as well have a windows app which stores everything locally but synchs/commits to the remote database server occasionally.

    Given that you seem to have an application already then maybe the latter option is something to consider anyhow.  There's quite a learning curve to silverlight and if you know winforms then maybe a totally separate winforms app is worth thinking about.

    Incidentally, you don't need to have asp.net 4 to use silverlight 4.  So you wouldn't absolutely have to upgrade the asp.net web site if you wanted to use silverlight 4.

    Friday, January 21, 2011 10:56 AM
  • The others may know something I don't but if you need to use a html solution and want to take it offline then Silverlight isn't the answer. The problem with offline is if you are truly offline then the browser needs to know and any links it makes to resources will fail. This is why Google Gears was an install as it would intercept such calls and supply cached versions of the resources, i.e. it acted like a little web server. You can do bits with SL and isolated storage but you have to work hard to avoid the problems I've just mentioned. You could change your implementation and go for a full Silverlight OOB application and that would be fine, but there is no, "I'm working on the html page and now the app has switched me to the OOB version"...I'd like that feature.  If you can upgrade your site to HTML5 then that maybe a better choice...much as it pains me to say so. Hopefully there will be something in SL5 to close the gap.



    Saturday, January 22, 2011 9:02 PM
  • Occasionally connected silverlight apps are a fact mate.  They are not html.

    They don't span multiple html pages so they don't necessarilly require any extra resources.

    You put everything into one xap and the user sits in the same html page even though it looks to him like there are multiple pages. 

    You can check to see if you still have internet connectivity.

    It's not a great way to go for rarely connnected apps though - because silverlight really wants to use web services for data.  WIth wpf you can have a local database.  With silverlight a local database would mean running a web server on the client.  That's possible but has obvious limitations.

    They are really only suited to those sort of apps where you're just going to be disconnected briefly and must not lose your data AND won't need to go read any extrad data off the main database in mid process.

    Google gears is kind of interesting but hasn't it been dropped by Google?

    Monday, January 24, 2011 8:37 AM
  • Yeah I agree it's fine for a quick drop out but it sounds like the original post was a web application that needs to start when no connection exists, and that scuppers SL unless you rely on caching...too risky IMO. Gears was dropped, and I'm not that surprised because of all the interception work it was a lot to stomache/install on your machine, esp. from Google ;) However, I guess the real reason is cause you can implement offline via HTML5 and I guess Google saw it as two conflicting solutions. What I want is to clear the SL mess up around this and OOB and have a much better transition from html web hosted to OOB, AIR seems to do a passable job at it.


    Monday, January 24, 2011 5:58 PM
  • Silverlight able to use a local database would be great.  The ability to allocate raised authority to Silverlight apps which aren't OOB would also be great. 

    If they have any sense then ms will be covering both for mobile apps. 

    Rarely connected apps really need a database on the device and making it a browser based app at all is kind of ignoring the obvious IMO.  I can't help but feel that whoever is in charge of strategy on Win Phone 7 and Win CE 7 needs to get out there and try relying on a device has to be connected all the time.  That guy delivering the parcels or collecting data on his handheld will be using something with WinMo 6.x on it until SQL CE works on later versions.

    If it's a rarely connected app for an admin to use then something like Access would be the simplest way to put something together.   Maybe Access front end with a sync'd SQL server express back end.

    Tuesday, January 25, 2011 8:25 AM
  • Andy, IMO, MS are hell bent on pushing Azure. So there is no need for local databases right, right??? Hmm. If only we all could afford, or even get access to, 3/4G phones networks. Anyway that's a different topic, sorry. There are some interesting databases that are based around isolated storage, 'Sterling' being one.




    Wednesday, January 26, 2011 9:18 AM
  • Azure's the answer - what did you say was the problem again :^)

    Problem isn't really affording the phones.

    Connectivity often isn't available out there in the real world and some apps need a shed load of data.  I wrote a silverlight presentation app for one client.  Raised the issue of occasional connectivity.  They didn't want to spend any extra time worrying about that.  Several conversations later.... Converted it to WPF.  Turns out many clients don't even have a wi-fi network let alone allow salesmen to connect via it.  With oneclick it's arguable whether browser based delivery offers any advantage outweighing it's limits and costs for any in-house app.

    Then there was the pipes app.  I mean water pipes.  England's a pretty small place - so 90% coverage will be fine right?Turns out once you're in them thar hills any sort of signal is pretty tricky and data just ain't going to happen.  Pipes run underground.  So do trains.  Then there are steel skinned buildings.

    There's a resistance in businesses against adopting new technology if the old version works better.  Win Mo 6.x has sql ce which works pretty well.

    That guy delivering your parcel ain't going  to be using Win Phone 7+ until it has sql on it. 

    More than I intended typing, ah well.

    Wednesday, January 26, 2011 12:15 PM
  • Yep I agree, using Scenarios and Persona's to create the wp model is great...but you have to get them right. All of them seem to revolve around rich 30 somethings living in an always-connected part of Seatle. Oh well.


    Thursday, January 27, 2011 10:33 PM