如何在 WebClient 中设置 User-Agent [英] How to set User-Agent in WebClient
本文介绍了如何在 WebClient 中设置 User-Agent的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我使用下面的代码打开对 youtube 视频的流请求,但它总是返回异常远程服务器返回错误:NotFound".然后我尝试使用 Fiddler 来检测问题,我看到 WebClient 自动将 User-Agent 字段设置为 NativeHost,而不是我的 User-Agent 如下.
I used the code below to open a stream request to a youtube video, but it always return an exception "The remote server returned an error: NotFound". Then I tried to use Fiddler to detect the problem, and I saw that the WebClient auto set User-Agent field to NativeHost, not my User-Agent as below.
我向 youtube 发送请求的代码:
private static Task<string> HttpGet(string uri)
{
var task = new TaskCompletionSource<string>();
var web = new WebClient();
web.OpenReadCompleted += (sender, args) =>
{
if (args.Cancelled)
task.SetCanceled();
else if (args.Error != null)
task.SetException(args.Error);
else
{
//var bytes = args.Result.ReadToEnd();
byte[] bytes = new byte[] { };
using (MemoryStream memoryStream = new MemoryStream())
{
args.Result.CopyTo(memoryStream);
bytes = memoryStream.ToArray();
task.SetResult(Encoding.UTF8.GetString(bytes, 0, bytes.Length));
}
}
};
web.Headers[HttpRequestHeader.UserAgent] = "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)";
web.OpenReadAsync(new Uri(uri));
return task.Task;
}
从 Fiddler 捕获的标题:
CONNECT www.youtube.com:443 HTTP/1.0
User-Agent: NativeHost
Host: www.youtube.com:443
Content-Length: 0
Connection: Keep-Alive
Pragma: no-cache
请给我一些建议.非常感谢
Please give me some advice. Many thanks
推荐答案
您可以使用此代码
using (WebClient web = new WebClient())
{
web.Headers["User-Agent"] =
"Mozilla/4.0 (Compatible; Windows NT 5.1; MSIE 6.0) " +
"(compatible; MSIE 6.0; Windows NT 5.1; " +
".NET CLR 1.1.4322; .NET CLR 2.0.50727)";
}
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