WKWebView doesn't support custom NSURLProtocol (Score 2)

Since iOS 8, Apple recommends everybody uses the new WKWebView which replaces UIWebView: https://developer.apple.com/re...

However, WKWebView is not as flexible as UIWebView; more specifically, there is no support for a custom NSURLProtocol. Basically to get the performance gains of using WKWebView, you can't do the things you want to do.

For Opera specifically, this bug filed against webkit lays out the features they would like to implement, but are unable to: https://bugs.webkit.org/show_b...

Opera on iOS implements a custom HTTP(S) protocol to do:
1. Data savings (see http://www.opera.com/turbo ). This greatly improves connectivity under crappy network conditions for millions of users. It's especially important for people in countries which can only dream about 4G.
2. Peer-to-peer inobtrusive security. For that we collect bits of site security information that is only available via low-level network APIs.
3. Presenting sites as icons (and grouping multiple pages into the same icons). For that we hook into the HTML data stream to parse meta data ASAP. In addition we intercept and react on HTTP redirects. This is a part of the http://operacoast.com/ app identity.
4. Progress loading reporting, automatic retries on bad networks. For that we do traffic QoS monitoring.
5. Fast going back and offline content. That is controlled partially by a custom cache, and partially in NSURLProtocol.
6. Ad-blocking.