Mobile Safari 5mb HTML5 application cache limit?

Question

It's becoming evident in my testing that there's a 5mb size limit on Mobile Safari's implementation of HTML5's application cache.

Does anyone know how to circumvent or raise this? Is there some unexposed meta tag that I should know about? I have to cache some video content for an offline app and 5mb is not going to be enough.

Oast

Answer 1

I tried to write a simple test with this manifest:

CACHE MANIFEST
# 2010-06-20:v4

http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js
http://peach.blender.org/wp-content/uploads/big_big_buck_bunny.jpg
http://apod.nasa.gov/apod/image/9712/orionfull_jcc_big.jpg
http://www.thelivingmoon.com/43ancients/04images/Titan/titan5km_huygens_big.jpg
http://upload.yeuamnhac.com/musica/dan_lily/dancontent/rh108poster1big.jpg

This cache will need 11.4MB of storage.

When I open a page include that manifest file, it say something like that: "This website require to use up to 25MB of storage, do you want to increase local storage?".

I think I got what the way iOS do:

• You only have 5MB for local storage (include HTML5 application cache)
• If your web need more, Safari need user's agreement for some packages (up to 10MB, or 25MB, or more...)

Hope that useful for you.

Dug

Answer 2

This won't apply to the particular offline-video use case, but you can create Web SQL databases larger than the default 5MB in iOS by simply requesting a larger DB in the openDatabase call. For some kinds of storage, SQLite can be an acceptable solution.

Phane

Answer 3

Also contacted apple about this.

Read my blogpost about this here: http://techblog.viewbook.com/2011/02/mobile-safari-offline-application-cache-limit/

And my StackOverflow post here: Max size iPad / iPhone Offline Application Cache

Bobbette

Answer 4

What else is on the page?

These guys keep their pages under the limit by either splitting up the pages or replacing some of the cached images with links:
http://www.mobilenoter.com/blog/post/2010/04/06/Removing-size-limit-of-a-page.aspx

Tessietessier

I suppose that can be applied to video as well? Cut up the video into 5MB chunks. If there is no need for video seeking, I think the loader is quite trivial to implement. – Informer

Answer 5

I ran a web app that was larger then 5MB on an iPad (iOS 5) although it is an iPad once the page loaded past 5MB it presented a pop-up asking the user if he/she wanted to increase the size of the cache to 10MB.

I would appear that with the latest iOS version that if a web app needs more then 5MB of cache storage it will ask the user if it has permission to increase it so the user can manage his/her own memory space.

It would also stand to reason that when you view your usage data (say via iTunes) the amount you see in the "Other" category is probably web cache mostly. Also you can see how much space is being used per website by going to Settings | Safari | Advanced | Website Data.

Garter

Answer 6

Not sure why every forgets about the good 'ol Web apps (remember these guys? they were around before native apps!), but they're already "offline ready," which means that you don't need to load up your application cache with every component of your app.

To the best of my knowledge, there is no limit to the size of web apps.

http://www.apple.com/webapps/

Spiraea

It's actually a web app that I'm building -- one to show movies (html5 video tag) when user is offline for presentations etc. I can confirm that the cache size limit applies to web apps as well. – Oast