当从URL加载HTML5页面时，我在页面中得到了一个PDF文件，我必须下载该PDF文件或将其保存为base64格式。
这是PDF文件在HTML代码中的位置。我不能简单地点击“src”URL获取PDF文件。
< embed width="100%" height="100%" name="plugin" id="plugin" src="https://myurl.com/fileToOpen.pdf” type="application/pdf" internalinstanceid="8" title="">
有没有任何JS可以帮助我获取base64字符串或其他下载方法？
这个问题之前有人问过，但是如果有人正在寻找在File Manager上下载.pdf或任何文件的解决方案，并且希望使用WKWebView，那么这就是我得出的结论。
class WebPortalVC: UIViewController, WKNavigationDelegate,WKUIDelegate, UIDocumentInteractionControllerDelegate,URLSessionDownloadDelegate {
覆盖下面的函数，它将拦截url，在我们的情况下，我们检查url以.pdf和.csv结尾，并重定向到打开文件管理器视图。这使得可以查看文件、下载并保存到设备存储、使用airdrop或与其他应用程序共享。
只需添加以下函数并进行检查。
func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
if let url = navigationAction.request.url {
print("fileDownload: check :: \(url)")
let extention = "\(url)".suffix(4)
if extention == ".pdf" || extention == ".csv"{
print("fileDownload: redirect to download events. \(extention)")
DispatchQueue.main.async {
self.downloadPDF(tempUrl: "\(url)")
}
decisionHandler(.cancel)
return
}
}
decisionHandler(.allow)
}
func downloadPDF(tempUrl:String){
print("fileDownload: downloadPDF")
guard let url = URL(string: tempUrl) else { return }
let urlSession = URLSession(configuration: .default, delegate: self, delegateQueue: OperationQueue())
let downloadTask = urlSession.downloadTask(with: url)
downloadTask.resume()
//showHUD(isShowBackground: true); //show progress if you need
}
func documentInteractionControllerViewControllerForPreview(_ controller: UIDocumentInteractionController) -> UIViewController {
print("fileDownload: documentInteractionControllerViewControllerForPreview")
return self
}
func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
// create destination URL with the original pdf name
print("fileDownload: urlSession")
guard let url = downloadTask.originalRequest?.url else { return }
print("fileDownload: urlSession \(url)")
let documentsPath = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
let destinationURL = documentsPath.appendingPathComponent(url.lastPathComponent)
// delete original copy
try? FileManager.default.removeItem(at: destinationURL)
// copy from temp to Document
do {
try FileManager.default.copyItem(at: location, to: destinationURL)
myViewDocumentsmethod(PdfUrl:destinationURL)
print("fileDownload: downloadLocation", destinationURL)
DispatchQueue.main.async {
NBMaterialToast.showWithText(self.view, text: "Download Completed", duration: NBLunchDuration.long)
}
} catch let error {
print("fileDownload: error \(error.localizedDescription)")
}
// dismissHUD(isAnimated: false); //dismiss progress
}
func myViewDocumentsmethod(PdfUrl:URL){
print("fileDownload: myViewDocumentsmethod \(PdfUrl)")
DispatchQueue.main.async {
let controladorDoc = UIDocumentInteractionController(url: PdfUrl)
controladorDoc.delegate = self
controladorDoc.presentPreview(animated: true)
}
}
更新
根据文档，Fetch API提供了一个获取资源（包括跨网络）的接口。对于任何使用过XMLHttpRequest的人来说，它都会感觉很熟悉。
您还可以使用以下字符串从WKWebview获取base64字符串：
let s = "path = document.getElementById(\"plugin\").src\n" +
"\n" +
"fetch(path).then(function (response) {\n" +
" response.body.getReader().read().then(function(result) {\n" +
" return btoa(String.fromCharCode.apply(null, result.value));\n" +
" }).then(function(b64) {\n" +
" window.webkit.messageHandlers.myInterface.postMessage(b64);\n" +
" });\n" +
"});"
使用以下代码从javascript获取base64字符串到Swift中。我正在使用WKScriptMessageHandler来获取来自Javascript的回调当base64字符串准备好被消耗时。在字符串s中，您只需要传递pdf的url，它将执行ajax请求以获取pdf文件，然后将其转换为base64字符串。
import UIKit
import WebKit
class ViewController: UIViewController {
@IBOutlet weak var btnPDF: UIButton!
@IBOutlet weak var webViewParentView: UIView!
var activityIndicator: UIActivityIndicatorView?
var webView: WKWebView!
@objc func didSelect(_ sender: UIView){
let s="var xhr = new XMLHttpRequest();\n" +
"xhr.open(\'GET\', \"https://codingexceptions.com/wkwebview/dummy.pdf\", true);\n" +
"\n" +
"xhr.responseType = \'arraybuffer\';\n" +
"\n" +
"xhr.onload = function(e) {\n" +
" if (this.status == 200) {\n" +
" var uInt8Array = new Uint8Array(this.response);\n" +
" var i = uInt8Array.length;\n" +
" var binaryString = new Array(i);\n" +
" while (i--)\n" +
" {\n" +
" binaryString[i] = String.fromCharCode(uInt8Array[i]);\n" +
" }\n" +
" var data = binaryString.join(\'\');\n" +
"\n" +
" var base64 = window.btoa(data);\n" +
"\n" +
"window.webkit.messageHandlers.myInterface.postMessage(base64);" +
"\n" +
" }\n" +
"};\n" +
"\n" +
"xhr.send();\n"
webView.configuration.userContentController.add(self, name: "myInterface")
webView?.evaluateJavaScript(s, completionHandler: {(string,error) in
print(error ?? "no error")
})
}
func setupWebView(){
webView = WKWebView.init(frame: CGRect(x: 0, y: 0, width: webViewParentView.frame.width, height: webViewParentView.frame.height))
webView.navigationDelegate = self
webViewParentView.addSubview(webView)
activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: .gray)
activityIndicator?.center = self.view.center
self.view.addSubview(activityIndicator!)
webView.load(URLRequest(url: URL(string: "https://codingexceptions.com/wkwebview/index.php")!))
activityIndicator?.startAnimating()
}
override func viewDidLoad() {
super.viewDidLoad()
btnPDF.addTarget(self, action: #selector(self.didSelect(_:)), for: .touchUpInside)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
setupWebView()
}
}
extension ViewController: WKScriptMessageHandler{
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
print("Message received: \(message.name) with body: \(message.body)")
}
}
extension ViewController: WKNavigationDelegate{
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
self.activityIndicator?.stopAnimating()
self.activityIndicator?.removeFromSuperview()
self.activityIndicator = nil
}
}
var url = document.getElementById("plugin").src
PS：将答案作为评论使用，因为我需要格式
您应该在Webview中执行以下JavaScript代码
path = document.getElementById("plugin").src
fetch(path).then(function (response) {
response.body.getReader().read().then(function(result) {
return btoa(String.fromCharCode.apply(null, result.value));
}).then(function(b64) {
window.pdf_data = b64;
});
});
那么你可以执行另一个查询来访问 window.pdf_data，假设从javascript执行中获取返回值是可能的？
您想将PDF下载到iPhone还是Mac上？通常情况下，直接在iPhone上下载PDF是不可能的，因为iPhone本身没有存储PDF的能力。您需要拥有iBooks或iCloud Drive，然后在另一个窗口中打开PDF，再手动下载。在下载PDF之前仍需要用户交互，也就是说用户必须批准下载。通过将JavaScript注入WKWebView实例进行直接下载是不可能的。