Question

我搜索了各种论坛和链接，但还没有得到任何帮助。

实际上我正致力于使用C＃在ASP.net中开发Web应用程序，该应用程序允许用户登录远程服务器，然后从该服务器下载文件。

我可以登录该服务器并查看受保护页面的内容。

但是在下载文件时，我收到了Unauthorize访问错误。

我可以从服务器下载图像，但这些图像不受保护。

我到目前为止开发的代码是

    protected void Unnamed1_Click(object sender, EventArgs e)
{
    try
    {

        string LOGIN_URL = "https://some.server/";

        // first, request the login form to get the value

        HttpWebRequest webRequest = WebRequest.Create(LOGIN_URL) as HttpWebRequest;
        webRequest.ContentType = "application/x-www-form-urlencoded";
        webRequest.KeepAlive = true;
        webRequest.UserAgent = userAgent;
        String received = Encoding.ASCII.GetString(Request.BinaryRead(Request.ContentLength));
        webRequest.ContentLength = received.Length;
        webRequest.Proxy.Credentials = new NetworkCredential("usrname", "password", "domain");
        StreamReader responseReader = new StreamReader(webRequest.GetResponse().GetResponseStream(), Encoding.ASCII);
        string responseData = responseReader.ReadToEnd();
        responseReader.Close();
        string postData = "user=usr&password=pass&switch=Login";
        Response.Write(webRequest.Address);

        // have a cookie container ready to receive the forms auth cookie

        CookieContainer cookies = new CookieContainer();

        // now post to the login form

        webRequest = WebRequest.Create(LOGIN_URL) as HttpWebRequest;
        webRequest.Method = "POST";
        webRequest.ContentType = "application/x-www-form-urlencoded";
        webRequest.CookieContainer = cookies;

        // write the form values into the request message

        StreamWriter requestWriter = new StreamWriter(webRequest.GetRequestStream());
        requestWriter.Write(postData);
        requestWriter.Close();

        // we don't need the contents of the response, just the cookie it issues 

        webRequest.GetResponse().Close();



        // Download files

        WebProxy myProxy = new WebProxy("server.https.com", 443);
        //WebRequest request = WebRequest.Create("https://some.server/file.zip");
        WebRequest request = WebRequest.Create("https://some.server/file.zip");
        request.Proxy.Credentials = new NetworkCredential("usrname", "password", "domain");

        string filename = "file.zip";
        string filepath = "C:\\Documents and Settings\\user\\Desktop\\" + filename.ToString();

        WebClient client = new WebClient();
        client.Credentials = new NetworkCredential("usrname", "password", "domain");
        client.DownloadFile("https://some.server/file.zip", filepath);
    }
    catch (Exception exp)
    {
        Response.Write(exp.ToString());
    }
}

服务器错误。

远程服务器返回错误：（401）未经授权。描述：执行当前Web请求期间发生未处理的异常。请查看堆栈跟踪以获取有关错误及其源自代码的位置的更多信息。

异常详细信息：System.Net.WebException：远程服务器返回错误：（401）未经授权。

来源错误：

第80行：WebClient客户端=新WebClient（）;

第81行：client.Credentials = new NetworkCredential（“username”，“password”，“domain”）;

第82行：client.DownloadFile（“https：//some.server/file.zip”，filepath）;

Answer 1

使用从WebClient派生的此类。每次请求都会传递cookie。

class WebClientWithCookies: WebClient
{
    private CookieContainer _container = new CookieContainer();

    protected override WebRequest GetWebRequest(Uri address) 
    {
        HttpWebRequest request = base.GetWebRequest(address) as HttpWebRequest; 

        if (request != null) 
        { 
            request.Method = "Post";
            request.CookieContainer = _container; 
        } 

        return request;
    }
}

Answer 2

尝试检查此库：http://www.rebex.net/default.aspx

asp.net从受保护的服务器下载文件

2 个答案: