如何在C#中使用HTTP GET请求并带有SSL？（协议违规）

Question

我目前正在尝试在C＃中从使用SSL的服务器获取响应。我有Java代码可以做到这一点，但看起来它们并不能逐字翻译。

我找到了一些可用于常规页面的代码，但对于我需要的那个页面不起作用（也许是因为SSL的原因）。以下是代码：

        WebRequest request = WebRequest.Create("https://" + sslServerHost + ":" + sslServerPort);
    request.Proxy = null;
    request.Credentials = CredentialCache.DefaultCredentials;

    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    Stream dataStream = response.GetResponseStream();
    StreamReader reader = new StreamReader(dataStream);
    string responseFromServer = reader.ReadToEnd();

更新：很抱歉，我似乎忘记了错误是什么。 我在“HttpWebResponse response = (HttpWebResponse)request.GetResponse();��这一行处收到协议违规异常。 有什么想法吗？谢谢大家。

- Amber

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请描述出现了什么问题？它只是没有返回结果吗？你是否收到了某种异常？如果是这样，是什么类型的异常，以及消息是什么？ - JMarsch

可能是不受信任的证书问题？ - Dscoduc

Answer 1

通过SSL进行的HTTP对话需要使用正确颁发的证书进行验证。

您可以使用RemoteCertificateValidationCallback委托来验证SSL证书，如下所示：

public static void ConnectSSL()
{

    WebRequest request = WebRequest.Create("https://" + sslServerHost + ":" + sslServerPort);
    request.Proxy = null;
    request.Credentials = CredentialCache.DefaultCredentials;

   //allows for validation of SSL certificates 

    ServicePointManager.ServerCertificateValidationCallback += new  System.Net.Security.RemoteCertificateValidationCallback(ValidateServerCertificate);

    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    Stream dataStream = response.GetResponseStream();
    StreamReader reader = new StreamReader(dataStream);
    string responseFromServer = reader.ReadToEnd();

}

//for testing purpose only, accept any dodgy certificate... 
public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
          return true; 
}

- aamit

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请确保正确处理HttpWebResponse对象，或者至少在finally块中调用Close()方法以释放资源！ - Mike Atlas

Answer 2

只是一个想法，你试过在末尾加上“/”吗？另外，你可能会觉得这种方法更容易：

string s;
using(WebClient client = new WebClient()) {
    client.UseDefaultCredentials = true;
    s = client.DownloadString("https://" + sslServerHost + ":"
       + sslServerPort + "/");
}

- Marc Gravell

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谢谢你的建议，但是不行。 - Amber

Answer 3

这里是一些测试代码，我已经成功地用它来测试SSL连接...

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://www.dscoduc.com");
//request.Method = "HEAD";
//request.AllowAutoRedirect = false;
request.Credentials = CredentialCache.DefaultCredentials;

// Ignore Certificate validation failures (aka untrusted certificate + certificate chains)
ServicePointManager.ServerCertificateValidationCallback = ((sender, certificate, chain, sslPolicyErrors) => true); 

HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream resStream = response.GetResponseStream();
StreamReader reader = new StreamReader(resStream);
string responseFromServer = reader.ReadToEnd();

- Dscoduc