为什么代码在 c# Interactive (Roslyn) 和调试\发布模式下表现不同？

Question

更新 实际上，在挖掘网络监控之后，我发现请求方式的差异是由执行 Roslyn 的代码和正常的调试\发布模式产生的。 debug\release 模式下 Fiddler 跟踪报错：

[Fiddler] The connection to 'host.com' failed.  <br/>System.Security.SecurityException Failed to negotiate HTTPS connection with server.fiddler.network.https&gt; HTTPS handshake to host.com (for #76) failed. System.IO.IOException Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. &lt; An existing connection was forcibly closed by the remote host

原始问题： 我得到了一段代码：

HttpTransportOverWebClient c = new HttpTransportOverWebClient();
c.GetURL("https://web.page/query")

GetUrl 是一些包装器：

public bool GetURL(string URL)
        {
            try
            {
                web.Headers.Add("User-Agent", browserAgent);
                byte[] data = web.DownloadData(URL);
                string characterSet = web.Response.CharacterSet;
                string encoding = (characterSet == null || characterSet == "" || characterSet.ToUpper() == "NONE") ? "UTF-8" : web.Response.CharacterSet.ToUpper();
                html = Encoding.GetEncoding(encoding).GetString(data);
                return true;
            }
            catch (Exception ex)
            {
                lastException = web.LastException == null ? new WebException(ex.Message) : web.LastException;
            }
            return false;
        }

c#Interactive 模式下的行为：

GetURL 返回 true 并且 html 包含数据

调试\发布模式下的行为：

GetURL 返回 false 并且 ex 包含以下错误：

An exception occurred during a WebClient request.
   at System.Net.WebClient.DownloadDataInternal(Uri address, WebRequest& request)
   at System.Net.WebClient.DownloadData(Uri address)
   at HttpCrawler.HttpTransportOverWebClient.GetURL(String URL) in ..HttpTransportOverWebClient.cs:line xx

内部异常：

 at System.Net.WebClient.DownloadBitsState.SetResponse(WebResponse response)
   at System.Net.WebClient.DownloadBits(WebRequest request, Stream writeStream, CompletionDelegate completionDelegate, AsyncOperation asyncOp)
   at System.Net.WebClient.DownloadDataInternal(Uri address, WebRequest& request)

请多指教

Answer 1

解决方案

我想 C#interactive 以某种方式预先配置，它能够将 ServicePointManager.SecurityProtocol 默认为旧版本。作为解决方案，我添加到代码中：

using System.Net;
....
ServicePointManager.SecurityProtocol = 
       SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;