wkwebview: find out if loaded content in web view is PDF and give download button

Question

I am using wkWebView to load research papers published on IEEE, Science Direct, etc. so when I click on any PDF in the research papers, PDF gets loaded into webview, so is there a way to detect and enable a download icon in wkWebView.

Tried Solution: I have tried to get the pdf from URLs via URLSession and this is working for like 95% of the times but sometimes I don't get the content of PDF via URLSession and pdf gets loaded into webview because of dynamic URL/PDF creation.

In research, I came across: Get already loaded PDF directly from WKWebView without downloading again But in my case first I need to check if the loaded content is PDF.

A relevant question: add download button for pdf in wkwebview in swift 4 But no answer!!!

To test: open URL: https://www.sciencedirect.com/science/article/pii/S0946672X17308763 in wkWebView and click on the "Download PDF" button this will load the pdf into webview.

In short: Any way to detect if the loaded content is PDF and give a download button to download the pdf content into the documents folder.

Any help appreciated...Thanks

Answer 1

You can detect if the content of the current page is a PDF by checking its mime/content type via the DOM Document.contentType API. If it's application/pdf, we know the web view is currently displaying a PDF, and can show a download button:

func isCurrentDocumentPDF(_ onCompletion: (Bool) -> Void) {
    webView.evaluateJavascript("document.contentType") {
        _, result in

        if let contentType = result as? String, contentType == "application/pdf" {
            onCompletion(true)
        } else {
            onCompletion(false)
        }
    }
}

isCurrentDocumentPDF() {
    isPDF in

    if isPDF {
        pdfDownloadButton.isHidden = false
    }
}