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使用HtmlAgilityPack获取url内容会产生错误

html-agility-pack webforms asp.net c#

Learning · 技术社区 · 6 年前

我正在使用 HtmlAgilityPack 从url抓取文本,这对大多数网站来说都很好,对一些网站来说,今天开始返回错误。

行代码后出现错误 doc = webGet.Load(url); 错误消息: The underlying connection was closed: An unexpected error occurred on a send.

link

我尝试了https网址,比如bbc.com它对它有用。任何指针,如果他们的代码有问题

 HtmlDocument doc = new HtmlDocument();
            var url = txtGrabNewsURL.Text.Trim();

        var webGet = new HtmlWeb();
        doc = webGet.Load(url);
        var baseUrl = new Uri(url);
        //  doc.LoadHtml(response);

        String title = (from x in doc.DocumentNode.Descendants()
                        where x.Name.ToLower() == "title"
                        select x.InnerText).FirstOrDefault();

        String desc = (from x in doc.DocumentNode.Descendants()
                       where x.Name.ToLower() == "meta"
                       && x.Attributes["name"] != null
                       && x.Attributes["name"].Value.ToLower() == "description"
                       select x.Attributes["content"].Value).FirstOrDefault();

        String ogImage = (from x in doc.DocumentNode.Descendants()
                          where x.Name.ToLower() == "meta"
                          && x.Attributes["property"] != null
                          && x.Attributes["property"].Value.ToLower() == "og:image"
                          select x.Attributes["content"].Value).FirstOrDefault();


        List<String> imgs = (from x in doc.DocumentNode.Descendants()
                             where x.Name.ToLower() == "img"
                              && x.Attributes["src"] != null
                             select x.Attributes["src"].Value).ToList<String>();

        List<String> imgList = (from x in doc.DocumentNode.Descendants("img")
                                where x.Attributes["src"] != null
                                select x.Attributes["src"].Value.ToLower()).ToList<String>();

完整错误详细信息

System.Net.WebException was caught
  HResult=-2146233079
  Message=The underlying connection was closed: An unexpected error occurred on a send.
  Source=System
  StackTrace:
       at System.Net.HttpWebRequest.GetResponse()
       at HtmlAgilityPack.HtmlWeb.Get(Uri uri, String method, String path, HtmlDocument doc, IWebProxy proxy, ICredentials creds) in D:\Source\htmlagilitypack.new\Trunk\HtmlAgilityPack\HtmlWeb.cs:line 1355
       at HtmlAgilityPack.HtmlWeb.LoadUrl(Uri uri, String method, WebProxy proxy, NetworkCredential creds) in D:\Source\htmlagilitypack.new\Trunk\HtmlAgilityPack\HtmlWeb.cs:line 1479
       at HtmlAgilityPack.HtmlWeb.Load(String url, String method) in D:\Source\htmlagilitypack.new\Trunk\HtmlAgilityPack\HtmlWeb.cs:line 1106
       at HtmlAgilityPack.HtmlWeb.Load(String url) in D:\Source\htmlagilitypack.new\Trunk\HtmlAgilityPack\HtmlWeb.cs:line 1061
       at _admin_News.btnGrabNews_Click(Object sender, EventArgs e) in c:\path\News.aspx.cs:line 361
  InnerException: System.IO.IOException
       HResult=-2146232800
       Message=Authentication failed because the remote party has closed the transport stream.
       Source=System
       StackTrace:
            at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
            at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
            at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
            at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
            at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
            at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
            at System.Net.TlsStream.CallProcessAuthentication(Object state)
            at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
            at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
            at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
            at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result)
            at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)
            at System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, Int32 size)
            at System.Net.ConnectStream.WriteHeaders(Boolean async)
       InnerException:

2 回复 | 直到 6 年前

Micah Epps Etienne Maheu 6 年前

如果它只发生在HTTP上 S码如果您的目标是.NET4,那么它可能与默认的SSL/TLS支持有关。请尝试以下操作:

using System.Net;

static void Main()
{
    //place this anywhere in your code prior to invoking the Web request
    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12 |  SecurityProtocolType.Ssl3; 
}

Anup Patil 6 年前

我以为当时网站不工作,连接出现问题。

   HtmlDocument doc = new HtmlDocument();
        var url = "https://m.gulfnews.com/business/sectors/banking/rebuilding-lives-10-years-after-lehman-s-fall-1.2277318"

    var webGet = new HtmlWeb();
    doc = webGet.Load(url);

    String title = (from x in doc.DocumentNode.Descendants()
                    where x.Name.ToLower() == "title"
                    select x.InnerText).FirstOrDefault();

产出:重建生活,10。等等。