Enable Application cache in WKWebView

Question

I am aware that offline application cache is not supported in iOS WKWebView.

This is enabled in Safari, so I searched webkit project for the responsible code & found this

WKPreferences

- (void)_setOfflineApplicationCacheIsEnabled:(BOOL)offlineApplicationCacheIsEnabled;

Anyone familiar with this method? is it possible to enable app cache in iOS by accessing this private methods? (I am not going to ship the app to Appstore)

Answer 1

Yes, we can enable App cache by accessing private API

Create a category for WKPreferences and add to following method signature.

@interface WKPreferences (MyPreferences)
- (void)_setOfflineApplicationCacheIsEnabled:(BOOL)offlineApplicationCacheIsEnabled;
@end

(I tried performSelector:withObject: but it didn't work. No idea why)

After initializing the WKWebView, enable the appcache by calling the above method in the following object

  [_wkWebView.configuration.preferences _setOfflineApplicationCacheIsEnabled:YES];

It will create the ApplicationCache.db file in the Cache directory and allow the web app to work offline.

Warning :

2.5. Apps that use non-public APIs will be rejected

Answer 2

According to this tweet from at Apple, as of iOS 10, App Cache is now supported in WKWebView:

https://twitter.com/andersca/status/743259582252879872

...as does this WebKit bug report:

https://bugs.webkit.org/show_bug.cgi?id=152490

I've tested this in WKWebView using this site:

http://webdbg.com/test/appcache/

and can confirm it works as expected both in the iOS Simulator and on devices running iOS 10.