android - flutter_inappwebview 和 flutter_downloader - 不知道我做错了什么?
问题描述
前期资料:
Language: Flutter/Dart
Flutter Packages: flutter_inappwebview, flutter_downloader
我在使用 Flutter 为 Android 构建的移动应用程序时遇到问题。该应用程序的一项功能是能够下载与 PDF 文件关联的链接。这些文件位于应用程序已经访问的服务器上。用户已通过应用程序登录,因此已建立身份验证。当单击具有 PDF 的 URL 时,它会执行重定向,并返回并下载主页(index.php)。我不知道这是如何发生的,但我有想法。
- 我需要在当前的 web 视图中进行下载(如在同一会话和窗口中)。
- 禁用 URL 重定向。
- 弄清楚为什么要重定向链接以进行身份验证(假设它正在重定向到主页)。
任何想法或帮助将不胜感激。也很高兴提供更多信息。
在 main.dart 中:
onDownloadStart: (controller, url) async {
print("onDownloadStart $url");
final taskId = await FlutterDownloader.enqueue(
headers: {'My-Custom-Header': 'custom_value=564hgf34'},
url: url,
savedDir: (await getExternalStorageDirectory()).path,
showNotification: true, // show download progress in status bar (for Android)
openFileFromNotification: true, // click on notification to open downloaded file (for Android)
);
return taskId;
},
记录:
I/flutter (28552): onDownloadStart https://hjhvtc.online/pluginfile.php/6723/mod_resource/content/1/Automotive%20industry%20jobs.pdf
W/WM-WorkSpec(28552): Backoff delay duration less than minimum value
D/DownloadWorker(28552): DownloadWorker{url=https://hjhvtc.online/pluginfile.php/6723/mod_resource/content/1/Automotive%20industry%20jobs.pdf,filename=null,savedDir=/storage/emulated/0/Android/data/com.coffeepaulconsulting.hjhvtconline/files,header={"My-Custom-Header": "custom_value=564hgf34"},isResume=false
D/DownloadWorker(28552): Update notification: {notificationId: 1, title: https://hjhvtc.online/pluginfile.php/6723/mod_resource/content/1/Automotive%20industry%20jobs.pdf, status: 2, progress: 0}
D/DownloadWorker(28552): Open connection to https://hjhvtc.online/pluginfile.php/6723/mod_resource/content/1/Automotive%20industry%20jobs.pdf
D/DownloadWorker(28552): Headers = {"My-Custom-Header": "custom_value=564hgf34"}
D/DownloadWorker(28552): Response with redirection code
D/DownloadWorker(28552): Location = https://hjhvtc.online/login/index.php
D/DownloadWorker(28552): New url: https://hjhvtc.online/login/index.php
D/DownloadWorker(28552): Open connection to https://hjhvtc.online/login/index.php
D/DownloadWorker(28552): Headers = {"My-Custom-Header": "custom_value=564hgf34"}
V/InputMethodManager(28552): b/117267690: Failed to get fallback IMM with expected displayId=197 actual IMM#displayId=0 view=com.pichillilorenzo.flutter_inappwebview.InAppWebView.InAppWebView{4592e22 VFEDHVCL. ......ID 0,0-1080,1997}
D/DownloadWorker(28552): Content-Type = text/html; charset=utf-8
D/DownloadWorker(28552): Content-Length = -1
D/DownloadWorker(28552): Charset = UTF-8
D/DownloadWorker(28552): Content-Disposition = null
D/DownloadWorker(28552): fileName = index.php
D/DownloadWorker(28552): Update too frequently!!!!, this should be dropped
D/DownloadWorker(28552): There's no application that can open the file /storage/emulated/0/Android/data/com.coffeepaulconsulting.hjhvtconline/files/index.php
D/DownloadWorker(28552): Update too frequently!!!!, but it is the final update, we should sleep a second to ensure the update call can be processed
D/DownloadWorker(28552): Update notification: {notificationId: 1, title: index.php, status: 3, progress: 100}
D/DownloadWorker(28552): File downloaded
I/WM-WorkerWrapper(28552): Worker result SUCCESS for Work [ id=633dd93d-99e3-46e2-937d-a4782d62a569, tags={ flutter_download_task, vn.hunghd.flutterdownloader.DownloadWorker } ]
解决方案
经过几次尝试,我终于找到了解决方案。DownloadWorker 被重定向到登录页面,因为尽管用户在 InAppWebView 中进行了身份验证,但 Flutter 下载器似乎在单独的上下文中运行,因此用户未经过身份验证。
为了维护用户会话,我创建了一个变量:
// Store cookies to save user session for download
String cookiesString = '';
然后,我创建了updateCookies
从 中检索 cookieCookieManager
并更新cookiesString
变量的函数:
Future<void> updateCookies(Uri url) async {
List<Cookie> cookies = await CookieManager().getCookies(url: url);
cookiesString = '';
for (Cookie cookie in cookies) {
cookiesString += '${cookie.name}=${cookie.value};';
}
print(cookiesString);
}
然后,我调用InAppWebViewupdateCookies
的事件监听器:onLoadStop
onLoadStop: (controller, url) async {
pullToRefreshController.endRefreshing();
if (url != null) {
await updateCookies(url);
}
setState(() {
this.url = url.toString();
urlController.text = this.url;
});
},
onDownloadStart
最后,我将 cookie 传递给事件侦听器中 FlutterDownloader 的标头:
await FlutterDownloader.enqueue(
headers: {
HttpHeaders.authorizationHeader: 'Basic ' +
authToken,
HttpHeaders.connectionHeader: 'keep-alive',
HttpHeaders.cookieHeader: cookiesString,
},
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