c# - 在 WebClient 中接受 Cookies？

Question

我刚开始尝试使用 C# WebClient。我所拥有的是下面的代码，它从网站获取 html 代码并将其写入 .txt 文件。我遇到的唯一问题是某些网站要求您在使用该网站之前接受 cookie。这导致的不是将真正的网站 html 代码写入 .txt 文件，而是写入 cookie 弹出 html 代码。

代码:

string downloadedString;
System.Net.WebClient client;

client = new System.Net.WebClient();
 
//"http://nl.wikipedia.org/wiki/Lijst_van_spelers_van_het_Nederlands_voetbalelftal"
downloadedString = client.DownloadString(textBox1.Text);

using (StreamWriter write = new StreamWriter("Data.txt"))
{
    write.Write(downloadedString);
}

那么解决这个问题的方法是什么？有人可以指引我走上正确的道路吗？

Answer 1

用法:

        CookieContainer cookieJar = new CookieContainer();
        cookieJar.Add(new Cookie("my_cookie", "cookie_value", "/", "mysite"));

        CookieAwareWebClient client = new CookieAwareWebClient(cookieJar);

        string response = client.DownloadString("http://example.com/response_with_cookie_only.php");

---

public class CookieAwareWebClient : WebClient
{
    public CookieContainer CookieContainer { get; set; }
    public Uri Uri { get; set; }

    public CookieAwareWebClient()
        : this(new CookieContainer())
    {
    }

    public CookieAwareWebClient(CookieContainer cookies)
    {
        this.CookieContainer = cookies;
    }

    protected override WebRequest GetWebRequest(Uri address)
    {
        WebRequest request = base.GetWebRequest(address);
        if (request is HttpWebRequest)
        {
            (request as HttpWebRequest).CookieContainer = this.CookieContainer;
        }
        HttpWebRequest httpRequest = (HttpWebRequest)request;
        httpRequest.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
        return httpRequest;
    }

    protected override WebResponse GetWebResponse(WebRequest request)
    {
        WebResponse response = base.GetWebResponse(request);
        String setCookieHeader = response.Headers[HttpResponseHeader.SetCookie];

        //do something if needed to parse out the cookie.
        if (setCookieHeader != null)
        {
            Cookie cookie = new Cookie(); //create cookie
            this.CookieContainer.SetCookies(request.RequestUri, setCookieHeader);
        }
        
        return response;
    }
}

您将看到 GetWebRequest 和 GetWebResponse 的两个覆盖方法。可以重写这些方法来处理 cookie 容器。