title: WKWebView analog of service worker
body: <p>I'm trying to implement part of app with <code>PWA</code> approach, that works fine on <code>Android</code>, but not for <code>iOS</code>. We need to have</p>
  
  <ul>
  <li>offline content availability</li>
  <li>option to update content dynamically (like special offers or so). With service worker we show prompt to update web content.</li>
  </ul>
  
  <p>As were mentioned <a href="https://stackoverflow.com/questions/49673399/service-workers-unavailable-in-wkwebview-in-ios-11-3">here</a> service workers are not supported within <code>WKWebView</code> (or <code>UIWebView</code>). So is there analog or alternative solution like smart cache control? </p>
  
  <p>Seems like it is possible to store some web content from app and be able to update it if something changes. May there is already a <code>framework/library/approach</code> for that purpose?</p>
  
  <p><strong>EDIT</strong>
  <a href="https://stackoverflow.com/questions/49673399/service-workers-unavailable-in-wkwebview-in-ios-11-3">Service Workers unavailable in WKWebView in iOS 11.3</a> - this question explains the status of ServiceWorkers in WKWebView, but no alternative is given. I would like to discuss any alternative solutions.</p>
  
  <p>One thing I discovered is <a href="https://github.com/xtools-at/iOS-PWA-Wrapper" rel="noreferrer">https://github.com/xtools-at/iOS-PWA-Wrapper</a>. It looks like working based on AppCache, but <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Using_the_application_cache#Browser_compatibility" rel="noreferrer">https://developer.mozilla.org/en-US/docs/Web/HTML/Using_the_application_cache#Browser_compatibility</a> says it is deprecated and adviced to use SW instead (which is not an option for PWA).</p>