The story of state: AppData, settings, and the process lifecycle (Channel 9)

The story of state: AppData, settings, and the process lifecycle

Date: October 31, 2012 from 1:45PM to 2:45PM

Day 2

B33 Baker

3-126

Speakers: Kraig Brockschmidt

(5)

6,976 Views

5 Comments

Video format

Option selected may change based on video formats available and browser capability.

Auto

Use our suggested format for this video.

Smooth Streaming

Adaptive bitrate streaming - little buffering but lower video quality at times of low bandwidth. Silverlight 5 required

Progressive

Traditional buffered video format. Silverlight 5 required

HTML5

For browsers that support H.264 MP4 or WebM video playback such as:
IE9+, Firefox 4+, Chrome 5+, or Safari 4+.

Flash

For browsers that have the Adobe Flash Player plugin installed.

Good question, Alex. Local and roaming app state is preserved across app updates. As I discuss in the talk, if you change the version number of the app data (as opposed to the version of the app), you use Windows.Storage.ApplicationData.SetVersionAsync to indicate that. The version applies to local/temp/roaming state as a whole.

If you uninstall the app, local and temp state is wholly deleted (the folders in appdata for your package are deleted). Roaming state will remain in the cloud for "a reasonable time" so it's still there if you reinstall the app. The time is something like a month, but there's no particular guarantee of the timeframe. But it will be there. This is to accommodate cases where you uninstall the app from a device and then reinstall or install on another device (e.g. you buy a new device, you clean off and sell your other one, then set up the new one).

Do note that if your roaming state is greater than the quota such that it *hasn't* been roamed, then it gets deleted along with everything else and there won't be present in the cloud.

.Kraig

Follow the Discussion

Subscribe to these comments

Sempf Bill Sempf

Oct 31, 2012 at 9:47 PM

There aren't many people on the planet who understand the underpinnings of WinJS better than Kraig. Very informative talk.
Alex

Nov 01, 2012 at 4:53 PM

How does the state managed across app updates/deletes/reinstalls? What stays and what is deleted?
gcowin

Nov 02, 2012 at 10:51 AM

Great session Kraig. State a great thread that brings together different API's and considerations. Enjoyed it.
KraigB

Nov 02, 2012 at 6:46 PM

Good question, Alex. Local and roaming app state is preserved across app updates. As I discuss in the talk, if you change the version number of the app data (as opposed to the version of the app), you use Windows.Storage.ApplicationData.SetVersionAsync to indicate that. The version applies to local/temp/roaming state as a whole.
If you uninstall the app, local and temp state is wholly deleted (the folders in appdata for your package are deleted). Roaming state will remain in the cloud for "a reasonable time" so it's still there if you reinstall the app. The time is something like a month, but there's no particular guarantee of the timeframe. But it will be there. This is to accommodate cases where you uninstall the app from a device and then reinstall or install on another device (e.g. you buy a new device, you clean off and sell your other one, then set up the new one).
Do note that if your roaming state is greater than the quota such that it *hasn't* been roamed, then it gets deleted along with everything else and there won't be present in the cloud.
.Kraig
Rohit

Nov 06, 2012 at 1:38 AM

This has to be by far the best session.