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Question about Updating Images

I am developing an application that uses a web service on a myRIO along with a gesture sensor to act as a slide presentation system (i.e. powerpoint).  The myRIO will run standalone and client can view the presentation by connecting to the myRIO over WiFi.

 

I have the code working to recognize gestures that change the current slide (image) in the presentation to the next or previous one.  I also have the web service configured to display this slide as an image in a browser.  However, as of now the user has to hit refresh on the client side to see the updated slide.

 

I have been looking at methods of having the client to perform some sort of auto-update to refresh this image.  I have been studying the example http://forums.ni.com/t5/LabVIEW-Web-Development/Getting-Started-Series-See-an-Image-of-the-Front-Pan... and considering trying to implement this approach to have the client automatically update the image that is being served by the web service.  However, this doesn't seem particularly efficient use of resources either for the client or the server.  Instead, I am thinking of having the client poll the server to request a timestamp of the last time the image has changed and if this is different from what it has in memory then to request an updated image.  I'm not exactly sure how to implement this or even if this is the best approach.  I would prefer a method where the server could push a new image only whenever it has changed but I haven't seen anything similar to this in your getting started examples.  Any advice on automating the experience for the client to where the images will automatically change on its browser as new slides are served up following the gestures would be appreciated.

 

Thanks,

 

Doug Harper

 

 

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