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We're trying to save the content (HTML) of WKWebView in a persistent storage (NSUserDefaults, CoreData or disk file). The user can see the same content when he re-enters the application with no internet connection. WKWebView doesn't use NSURLProtocol like UIWebView (see post here).
Although I have seen posts that "The offline application cache is not enabled in WKWebView." (Apple dev forums), I know that a solution exists.
I've learned of two possibilities, but I couldn't make them work:
1) If I open a website in Safari for Mac and select File >> Save As, it will appear the following option in the image below. For Mac apps exists [[[webView mainFrame] dataSource] webArchive], but on UIWebView or WKWebView there is no such API. But if I load a .webarchive file in Xcode on WKWebView (like the one I obtained from Mac Safari), then the content is displayed correctly (html, external images, video previews) if there is no internet connection. The .webarchive file is actually a plist (property list). I tried to use a mac framework that creates a .webarchive file, but it was incomplete.
2) I obtanined the HTML in webView:didFinishNavigation but it doesn't save external images, css, javascript
func webView(webView: WKWebView, didFinishNavigation navigation: WKNavigation!) {
webView.evaluateJavaScript("document.documentElement.outerHTML.toString()",
completionHandler: { (html: AnyObject?, error: NSError?) in
print(html)
})
}
We're struggling over a week and it is a main feature for us. Any idea is really appreciated.
Thank you!
596
Difference Between UIWebview and WKWebViewUIWebview is a part of UIKit, so it is available to your apps as standard. You don't need to import anything, it will we there by default. But WKWebView is run in a separate process to your app,. You need to import Webkit to use WKWebView in your app.
The current app manages the users login / session outside of the webview and sets the cookies required for authentication into the the NSHTTPCookieStore . Unfortunately new WKWebView doesn't use the cookies from the NSHTTPCookieStorage .
To check if your WKWebView has loaded easily implement the following method: import WebKit import UIKit class ViewController: UIViewController, WKNavigationDelegate { let webView = WKWebView() func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!)
I know I'm late, but I have recently been looking for a way to store web pages for offline reading, and still could't find any reliable solution that wouldn't depend on the page itself and wouldn't use the deprecated UIWebView. A lot of people write that one should use the existing HTTP caching, but WebKit seems to do a lot of stuff out-of-process, making it virtually impossible to enforce complete caching (see here or here). However, this question guided me into the right direction. Tinkering with the web archive approach, I found that it's actually quite easy to write your own web archive exporter.
As written in the question, web archives are just plist files, so all it takes is a crawler that extracts the required resources from the HTML page, downloads them all and stores them in a big plist file. This archive file can then later be loaded into the WKWebView via loadFileURL(URL:allowingReadAccessTo:).
I created a demo app that allows archiving from and restoring to a WKWebView using this approach: https://github.com/ernesto-elsaesser/OfflineWebView
EDIT: The archive generation code is now available as standalone Swift package: https://github.com/ernesto-elsaesser/WebArchiver
The implementation only depends on Fuzi for HTML parsing.
95
I would recommend investigating the feasibility of using App Cache, which is now supported in WKWebView as of iOS 10: https://stackoverflow.com/a/44333359/233602
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