具有凭据的WebClient仍未下载文件 [英] WebClient with credentials still not downloading file

问题描述

我正在尝试使用用户名/密码从网站下载文件.您需要为注册文件付费才能下载文件-我们已经完成了.我正在尝试传递用户名/密码并下载文件，如下所示:

I am trying to download files from a website with username/password. You need to pay for a registered account in order to download files - which we have done. I am attempting to pass in the username/password and download a file as follows:

if (docUrl != null)
            {
                if (!string.IsNullOrEmpty(username) && !string.IsNullOrEmpty(password))
                    this.WebClientInstance.Credentials = new NetworkCredential(username, password);

                fileData = this.WebClientInstance.DownloadData(docUrl);
                this.WebClientInstance.Dispose();
                isDataDownloaded = true;
            }

WebClientInstance是一个System.Net.WebClient.我调试并验证它是否可以设置凭据.我没有下载PDF，而是获得了一个HTML页面，该页面提示我登录以访问文件.我已验证用户名/密码正确.我使用相同的凭据通过WatiN抓取该网站.

WebClientInstance is a System.Net.WebClient. I debugged and verified that it is hitting the line to set credentials. Instead of downloading the PDF, I end up with an HTML page that prompts me to log in to get access to the file. I have verified that the username/password is correct. I use the same credentials to scrape the website with WatiN.

我还要在这里做什么吗?

Is there something else that I'm supposed to be doing here?

更新

好的，我已经进行了一些嗅探，并找到了一些有关此问题的有用信息.我仍然没有使它起作用，但是我想我离得更近了.首先，您需要创建一个支持cookie的WebClient，以扩展WebClient类，如下所示:

Okay, I've done some sniffing around and found some useful info on this issue. I still haven't gotten it to work, but I think I'm closer. First, you need to create a cookie aware WebClient that extends the WebClient class, as follows:

public class CookiesAwareWebClient : WebClient
{
    public CookieContainer CookieContainer { get; private set; }

    public CookiesAwareWebClient()
    {
        this.CookieContainer = new CookieContainer();
    }

    protected override WebRequest GetWebRequest(Uri address)
    {
        var webRequest = base.GetWebRequest(address);

        if (webRequest is HttpWebRequest)
            (webRequest as HttpWebRequest).CookieContainer = this.CookieContainer;

        return webRequest;
    }
}

下一步是使用WebClient.UploadValues()方法将登录信息上载到目标网站.认证和下载目标资源的完整过程如下:

Next is to use the WebClient.UploadValues() method to upload the login info to the target website. The full process of authenticating and downloading the target resource is as follows:

using (var webClient = new CookiesAwareWebClient())
                    {
                        var postData = new NameValueCollection()
                        {
                            { "userId", username },
                            { "password", password }
                        };

                        webClient.UploadValues(docUrl, postData);

                        fileData = webClient.DownloadData(docUrl);
                    }

对于使用表单身份验证的网站，我错了.这是一个JSP网站，并使用JSESSIONID.我已验证自己是否正在返回cookie，其中包含似乎是有效的32字节JSESSIONID值.

I was wrong about the site using forms auth. It is a JSP website and uses a JSESSIONID. I have verified that I am getting a cookie back with what appears to be a valid 32-byte JSESSIONID value.

但是，当我调用WebClient.DownloadData()时，它仍然仅返回重定向的登录页面.我试图通过将HttpWebRequest上的AllowAutoRedirect属性设置为false来解决此问题，但是它返回0个字节.

However, when I call WebClient.DownloadData() it is still only returning the redirected login page. I've tried to fix this by setting the AllowAutoRedirect property on the HttpWebRequest to false, but then it returns 0 bytes.

我还有其他需要做的事情，它不会重定向，并且在我通过身份验证后将带我到资源中吗?

Is there something else that I need to do so it won't redirect and will take me to the resource once I have authenticated?

推荐答案

(在问题编辑中回答.转换为社区Wiki答案.请参见

(Answered in a question edit. Converted to a community wiki answer. See Question with no answers, but issue solved in the comments (or extended in chat) )

OP写道:

已解决.所以问题出在我的耳朵之间.我将安全资源的URL传递给.UploadValues()方法，因为它会重定向到登录页面.但是，我确实需要从登录表单(提交时即输入)中传递URL，而不是登录页面本身.一旦这样做，它就可以正常工作.我想我现在要去寻找餐饮服务职业.

Solved. So the problem was between my ears. I was passing in the URL for the secure resource to the .UploadValues() method, knowing that it would redirect to the login page. However, I really needed to pass in the URL from the login form (where it goes upon submitting) - not the login page itself. Once I did that, it worked correctly. I think I'm going to go find a career in food service now.

链接

SO上已经发布了一些解决此问题的问题.起初我只是不知道自己在寻找什么，所以我没有看到那些……在解决此问题时，我在这里遇到了很多不错的资源:

There were already a few questions posted on SO that addressed this issue. I just didn't know what I was looking for at first so I didn't see those... Anywhere here are a couple good resources that I came across when working on this issue:

如何在两个之间维护cookie网址位于asp.net

尝试使用HttpWebRequest获取认证cookie

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