问题
While loading HTML5 page from url I'm getting pdf somewhere in that page and I have to download that pdf or save it as base64.
This is where the pdf is in the HTML code. I cannot simply hit the 'src' URL and get the pdf.
< embed width="100%" height="100%" name="plugin" id="plugin" src="https://myurl.com/fileToOpen.pdf” type="application/pdf" internalinstanceid="8" title="">
Any JS which can help me get base64 string of that or any other method to download?
回答1:
Update
From the Docs they say
The Fetch API provides an interface for fetching resources (including across the network). It will seem familiar to anyone who has used XMLHttpRequest
You can also use the following string to get the base64 String from the WKWebview
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" +
"});"
both fetch and xmlhttp works async.. all you need to do is wait when the processing gets completed pass it to the Swift using javascript's bridge to ios (WKScriptMessageHandler)
Use the following code to get the base64 string from javascript to Swift. I am using WKScriptMessageHandler to get the callback from Javascript when the base64 string is ready to be consumed. In the String s you just need to pass the url of the pdf and it will do a ajax request to get the pdf file and then convert it to base64 string.
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
}
}
Update: To get the source from the embed tag as pointed in @Tarun's answer
just put the below line in the starting of string variable s and pass the url in xhr.open
var url = document.getElementById("plugin").src
回答2:
PS: Using answer as comments, as I need formatting
You should execute the below JavaScript in the webview
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;
});
});
Then you can execute another query to access the window.pdf_data assuming get return value from a javascript execution is possible?
回答3:
This question asked sometimes back, But if someone looking for swift solution with WKWebView to download .pdf or any file on File manager, this is how I ended-up
class WebPortalVC: UIViewController, WKNavigationDelegate,WKUIDelegate, UIDocumentInteractionControllerDelegate,URLSessionDownloadDelegate {
override following function, that will intercept url, in our case we check ulr ending with .pdf and .csv and redirect to open with file manger view. which enable view file, download and save on device storage, airdrop or share with other apps
just add following functions and check.
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)
}
}
回答4:
Are you looking to download the PDF to your iPhone or to your Mac? Generally, it's not possible to download PDFs directly to your iPhone because the iPhone doesn't natively have the capability to store PDFs. You'd need to have iBooks or iCloud Drive and then open the PDF in another window, followed by manually downloading it. There would still need to be user-interaction before you download the PDF, meaning the user would have to approve the download. Direct download via the injection of JavaScript into a WKWebView instance is is not possible.
来源：https://stackoverflow.com/questions/48587958/download-embedded-pdf-loaded-in-wkwebview