HtmlAgilityPack 给出了格式错误的 html 问题

Question

我想从 html 文档中提取有意义的文本，并且我使用 html-agility-pack 来实现相同的目的。这是我的代码：

string convertedContent = HttpUtility.HtmlDecode(
    ConvertHtml(HtmlAgilityPack.HtmlEntity.DeEntitize(htmlAsString))
);

ConvertHtml:

public string ConvertHtml(string html)
{
    HtmlDocument doc = new HtmlDocument();
    doc.LoadHtml(html);

    StringWriter sw = new StringWriter();
    ConvertTo(doc.DocumentNode, sw);
    sw.Flush();
    return sw.ToString();
}

ConvertTo:

public void ConvertTo(HtmlAgilityPack.HtmlNode node, TextWriter outText)
{
    string html;
    switch (node.NodeType)
    {
        case HtmlAgilityPack.HtmlNodeType.Comment:
            // don't output comments
            break;

        case HtmlAgilityPack.HtmlNodeType.Document:
            foreach (HtmlNode subnode in node.ChildNodes)
            {
              ConvertTo(subnode, outText);
            }
            break;

        case HtmlAgilityPack.HtmlNodeType.Text:
            // script and style must not be output
            string parentName = node.ParentNode.Name;
            if ((parentName == "script") || (parentName == "style"))
                break;

            // get text
            html = ((HtmlTextNode)node).Text;

            // is it in fact a special closing node output as text?
            if (HtmlNode.IsOverlappedClosingElement(html))
                break;

            // check the text is meaningful and not a bunch of whitespaces
            if (html.Trim().Length > 0)
            {
                outText.Write(HtmlEntity.DeEntitize(html) + " ");
            }
            break;

        case HtmlAgilityPack.HtmlNodeType.Element:
            switch (node.Name)
            {
                case "p":
                    // treat paragraphs as crlf
                    outText.Write("\r\n");
                    break;
            }

            if (node.HasChildNodes)
            {
            foreach (HtmlNode subnode in node.ChildNodes)
             {
              ConvertTo(subnode, outText);
             }
            }
            break;
    }
}

现在在某些情况下，当 html 页面格式错误时（例如以下页面 - http://rareseeds.com/cart/products/Purple_of_Romagna_Artichoke-646-72.html 具有格式错误的元标记，例如 <meta content="text /html; charset=uft-8" http-equiv="Content-Type">) [注意“uft”而不是 utf] 当我尝试加载 html 时，我的代码正在呕吐文档。

有人可以建议我如何克服这些格式错误的 html 页面并仍然从 html 文档中提取相关文本吗？

谢谢， 卡皮尔

Answer 1

正如 HtmlAgilityPack 项目页面中所说，“解析器对‘现实世界’格式错误的 HTML 非常宽容”。但你描述的这种错误太严重了，可能无法纠正。您可以使用以下命令设置默认编码：

 HtmlDocument doc = new HtmlDocument();
 doc.OptionDefaultStreamEncoding = Encoding.UTF8;