iOS-如何从wkwebview获取缓存资源?

据我所知,wkwebview中加载的所有资源的缓存是由 违约: 真

记住,如果您请求相同的资源,webview将不会从internet加载内容,它将从缓存的资源中为您提供内容。对于请求相同的资源,可以使用 javascript 获取内容。

请看下面的代码。一旦加载pdf并点击save按钮。它将执行javascript代码,当数据准备好由javascript交付时

它会燃烧 window.webkit.messageHandlers.myInterface.postMessage(base64)

让viewcontroller知道数据已准备好共享。

你可以通过

1. 让它加载pdf

2. 关闭模拟器的互联网( see )

3. 点击保存按钮

您将获得base64格式的pdf数据。保存并共享:)

    import UIKit
    import WebKit
    class ViewController: UIViewController {

        @IBOutlet weak var webView: WKWebView!
        var activityIndicator: UIActivityIndicatorView?
        override func viewDidLoad() {
            super.viewDidLoad()

        }

        override func viewDidAppear(_ animated: Bool) {
            super.viewDidAppear(animated)
            activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: .gray)
            webView.navigationDelegate = self
            activityIndicator?.center = self.view.center
            self.view.addSubview(activityIndicator!)
            webView.configuration.userContentController.add(self, name: "myInterface")
            webView.load(URLRequest(url: URL(string: "http://www.africau.edu/images/default/sample.pdf")!))
            activityIndicator?.startAnimating()
        }

        @IBAction func saveAction(_ sender: Any) {
            let s = """
            var xhr = new XMLHttpRequest();
            xhr.open('GET', "\(webView.url?.absoluteString ?? "")", true);
            xhr.responseType = 'arraybuffer';
            xhr.onload = function(e) {
            if (this.status == 200) {
            var uInt8Array = new Uint8Array(this.response);
            var i = uInt8Array.length;
            var binaryString = new Array(i);
            while (i--){
            binaryString[i] = String.fromCharCode(uInt8Array[i]);
            }
            var data = binaryString.join('');
            var base64 = window.btoa(data);

       window.webkit.messageHandlers.myInterface.postMessage(base64);
            }
            };
            xhr.send();
            """




            webView?.evaluateJavaScript(s, completionHandler: {(string,error) in
                print(error ?? "no error")
            })
        }
    }

    extension ViewController: WKScriptMessageHandler{
      func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
    //    print("Message received: \(message.name) with body: \(message.body)")

        guard
          var documentsURL = (FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)).last,
          let convertedData = Data.init(base64Encoded: message.body as! String)
          else {
            //handle error when getting documents URL
            return
        }

        //name your file however you prefer
        documentsURL.appendPathComponent("sample.pdf")

        do {
          try convertedData.write(to: documentsURL)
        } catch {
          //handle write error here
        }

        //if you want to get a quick output of where your
        //file was saved from the simulator on your machine
        //just print the documentsURL and go there in Finder
        print(documentsURL)

        let activityViewController = UIActivityViewController.init(activityItems: [documentsURL], applicationActivities: nil)
        present(activityViewController, animated: true, completion: nil)
      }
    }

    extension ViewController: WKNavigationDelegate{
        func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
            self.activityIndicator?.stopAnimating()
            self.activityIndicator?.removeFromSuperview()
            self.activityIndicator = nil
        }
    }

顺便说一下,你提供的pdf链接使用的是http而不是https。为了测试的目的,在 info.plist

<key>NSAppTransportSecurity</key>
    <dict>
        <key>NSAllowsArbitraryLoadsInWebContent</key>
        <true/>
    </dict>