当 PDF 受 cookie 保护时，如何从 WebView 打开 PDF？

Question

I am trying to download and open a PDF file from my WebView. I have tried retrieving the cookie from the WebView, and setting the cookie on a DownloadManager.Request. When my BroadCastReceiver is triggered, the download status states that it has failed.

this.webView?.apply {
            settings.domStorageEnabled = true
            settings.javaScriptEnabled = true

            setDownloadListener { url, _, _, mimetype, _ ->
                Log.w("downloading file", url)
                val downloadUri = Uri.parse(url)
                val downloadRequest = DownloadManager.Request(downloadUri).apply {
                    setTitle("Title")
                    setDescription("Downloading file")
                    Log.w("path", "${downloadUri.lastPathSegment}")
                    setDestinationInExternalFilesDir(context, Environment.DIRECTORY_DOWNLOADS, downloadUri.lastPathSegment)
                    val cookie = getCookie("https://www.example.com", "example_cookie_name")
                    Log.w("cookie", "${cookie}")
                    addRequestHeader("Cookie", cookie)
                }

                val manager: DownloadManager = getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
                val downloadId = manager.enqueue(downloadRequest)

                registerReceiver(
                    object: BroadcastReceiver() {
                        override fun onReceive(context: Context?, intent: Intent?) {
                            Log.w("onReceive", "${intent?.action}")
                            if (intent !== null && DownloadManager.ACTION_DOWNLOAD_COMPLETE == intent.action) {
                                val cursor = manager.query(DownloadManager.Query().apply{ setFilterById(downloadId) })

                                if (cursor.moveToFirst()) {
                                    Log.w("onReceive", "cursor moved")
                                    val downloadStatus = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS))
                                    val downloadLocalUri = cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI))
                                    val downloadMimeType = cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_MEDIA_TYPE))
                                    Log.w("onReceive", "$downloadStatus $downloadLocalUri $downloadMimeType")
                                    if (downloadStatus == DownloadManager.STATUS_SUCCESSFUL && downloadLocalUri !== null) {
                                        val viewIntent = Intent(Intent.ACTION_VIEW).apply {
                                            this.setDataAndType(Uri.parse(downloadLocalUri), downloadMimeType)
                                        }
                                        if (viewIntent.resolveActivity(packageManager) !== null) {
                                            startActivity(
                                                Intent.createChooser(viewIntent, "Choose app")
                                            )
                                        } else {
                                            Toast.makeText(
                                                context,
                                                "No app available that can open file",
                                                Toast.LENGTH_SHORT
                                            )
                                                .show()
                                        }
                                    }
                                }


                            }
                        }
                    },
                    IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE)
                )
            }
}

Through the logging in this code, I can confirm that I am getting the cookie out of the WebView.

Is there a better approach to handle this? If not, how do I determine why the download is failing? Also, what am I doing wrong?

Ideally, I would also be able to download the file, and ensure it is deleted after the user has finished viewing the PDF.

Answer 1

You could try something like this before loading the webview's content.

fun setCookies() {
       val cookieManager = CookieManager.getInstance()
       val cookieString = "your_cookie_here"
       cookieManager.setCookie("domain_name_of_the_dowload_url", cookieString)
       cookieManager.setAcceptThirdPartyCookies(your_webview_here, true)
}

Answer 2

It turned out that the way I was retrieving the cookie was wrong, it ended up stripping out the key. For future reference, it is quite simple to set the cookie on the download request, with:

addRequestHeader("Cookie", CookieManager.getInstance().getCookie(url))