我正在寻找一个可以解析具有更多HTML特定功能的HTML文件的库/方法，而不仅仅是通用XML解析库。
15个回答
137
这是一个敏捷的HTML解析器，它构建了一个读/写DOM，并支持纯XPATH或XSLT（实际上您不必理解XPATH或XSLT就能使用它，不用担心...）。它是一个.NET代码库，允许您解析“网页之外”的HTML文件。解析器非常容忍“现实世界”中格式错误的HTML。对象模型与System.Xml提议的非常相似，但适用于HTML文档（或流）。
- marxidad
27
你可以使用TidyNet.Tidy将HTML转换为XHTML，然后再使用XML解析器。
另一个选择是使用内置引擎mshtml：
另一个选择是使用内置引擎mshtml：
using mshtml;
...
object[] oPageText = { html };
HTMLDocument doc = new HTMLDocumentClass();
IHTMLDocument2 doc2 = (IHTMLDocument2)doc;
doc2.write(oPageText);
这可以让您使用类似于javascript的函数，如getElementById（）
- Erlend
3
4称呼我为疯子吧，但我很难弄清如何使用mshtml。你有什么好的链接吗？ - Alex Baranosky
1@Alex，你需要包含Microsoft.mshtml，可以在这里找到更多信息：http://msdn.microsoft.com/zh-cn/library/aa290341(VS.71).aspx - Wilfred Knievel
我有一篇关于Tidy.Net和ManagedTidy的博客文章，两者都能够解析和验证(x)html文件。如果您不需要验证内容，我建议使用htmlagilitypack。http://www.jphellemons.nl/post/Tidy-your-HTML-with-AspNet-TidyManaged-vs-Tidynet.aspx - JP Hellemons
16
我发现了一个名为 Fizzler 的项目，它采用了类似于 jQuery/Sizzler 的方式来选择 HTML 元素。它基于 HTML Agility Pack。目前仅支持 CSS 选择器的子集，并处于测试版阶段，但使用 CSS 选择器而不是糟糕的 XPath，感觉非常酷和清新。
链接：http://code.google.com/p/fizzler/
链接：http://code.google.com/p/fizzler/
- Rob Volk
2
1谢谢，这看起来很有趣！我感到惊讶的是，鉴于jQuery的流行，很难找到受其启发的C#项目。现在如果我能找到一些文档操作和更高级遍历也包含在其中的东西就好了... :) - Funka
我今天刚刚使用了这个，不得不说，如果你懂jQuery的话，它非常容易使用。 - Chi Chan
10
你可以在不使用第三方产品和mshtml（即Interop）的情况下完成很多工作。可以使用System.Windows.Forms.WebBrowser，从那里可以执行诸如在HtmlDocument上执行"GetElementById"或在HtmlElements上执行"GetElementsByTagName"等操作。如果想要实际与浏览器进行交互（例如模拟按钮点击），可以使用少量反射（在我看来比Interop更好）来实现：
var wb = new WebBrowser()
...告诉浏览器导航（与此问题无关）。然后在Document_Completed事件中，您可以模拟点击，如下所示。
var doc = wb.Browser.Document
var elem = doc.GetElementById(elementId);
object obj = elem.DomElement;
System.Reflection.MethodInfo mi = obj.GetType().GetMethod("click");
mi.Invoke(obj, new object[0]);
你可以使用类似的反射技术来提交表单等操作。
享受吧。
- Alan
9
我写了一些提供“LINQ to HTML”功能的代码，想在这里分享一下。它基于Majestic 12。它获取Majestic-12的结果并生成LINQ XML元素。此时，您可以使用所有的LINQ to XML工具来处理HTML。例如：
IEnumerable<XNode> auctionNodes = Majestic12ToXml.Majestic12ToXml.ConvertNodesToXml(byteArrayOfAuctionHtml);
foreach (XElement anchorTag in auctionNodes.OfType<XElement>().DescendantsAndSelf("a")) {
if (anchorTag.Attribute("href") == null)
continue;
Console.WriteLine(anchorTag.Attribute("href").Value);
}
我想使用Majestic-12，因为我知道它具有与在实际网页中发现的HTML相关的许多内置知识。但是我发现将Majestic-12结果映射到LINQ可接受的XML需要额外的工作。我包含的代码可以完成大部分清理工作，但在使用时可能会遇到被拒绝的页面。您需要修复代码以解决此问题。当抛出异常时，请检查exception.Data["source"]，因为它很可能设置为导致异常的HTML标记。以良好的方式处理HTML有时并不容易...所以现在期望值是真实的低，这里是代码 :)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Majestic12;
using System.IO;
using System.Xml.Linq;
using System.Diagnostics;
using System.Text.RegularExpressions;
namespace Majestic12ToXml {
public class Majestic12ToXml {
static public IEnumerable<XNode> ConvertNodesToXml(byte[] htmlAsBytes) {
HTMLparser parser = OpenParser();
parser.Init(htmlAsBytes);
XElement currentNode = new XElement("document");
HTMLchunk m12chunk = null;
int xmlnsAttributeIndex = 0;
string originalHtml = "";
while ((m12chunk = parser.ParseNext()) != null) {
try {
Debug.Assert(!m12chunk.bHashMode); // popular default for Majestic-12 setting
XNode newNode = null;
XElement newNodesParent = null;
switch (m12chunk.oType) {
case HTMLchunkType.OpenTag:
// Tags are added as a child to the current tag,
// except when the new tag implies the closure of
// some number of ancestor tags.
newNode = ParseTagNode(m12chunk, originalHtml, ref xmlnsAttributeIndex);
if (newNode != null) {
currentNode = FindParentOfNewNode(m12chunk, originalHtml, currentNode);
newNodesParent = currentNode;
newNodesParent.Add(newNode);
currentNode = newNode as XElement;
}
break;
case HTMLchunkType.CloseTag:
if (m12chunk.bEndClosure) {
newNode = ParseTagNode(m12chunk, originalHtml, ref xmlnsAttributeIndex);
if (newNode != null) {
currentNode = FindParentOfNewNode(m12chunk, originalHtml, currentNode);
newNodesParent = currentNode;
newNodesParent.Add(newNode);
}
}
else {
XElement nodeToClose = currentNode;
string m12chunkCleanedTag = CleanupTagName(m12chunk.sTag, originalHtml);
while (nodeToClose != null && nodeToClose.Name.LocalName != m12chunkCleanedTag)
nodeToClose = nodeToClose.Parent;
if (nodeToClose != null)
currentNode = nodeToClose.Parent;
Debug.Assert(currentNode != null);
}
break;
case HTMLchunkType.Script:
newNode = new XElement("script", "REMOVED");
newNodesParent = currentNode;
newNodesParent.Add(newNode);
break;
case HTMLchunkType.Comment:
newNodesParent = currentNode;
if (m12chunk.sTag == "!--")
newNode = new XComment(m12chunk.oHTML);
else if (m12chunk.sTag == "![CDATA[")
newNode = new XCData(m12chunk.oHTML);
else
throw new Exception("Unrecognized comment sTag");
newNodesParent.Add(newNode);
break;
case HTMLchunkType.Text:
currentNode.Add(m12chunk.oHTML);
break;
default:
break;
}
}
catch (Exception e) {
var wrappedE = new Exception("Error using Majestic12.HTMLChunk, reason: " + e.Message, e);
// the original html is copied for tracing/debugging purposes
originalHtml = new string(htmlAsBytes.Skip(m12chunk.iChunkOffset)
.Take(m12chunk.iChunkLength)
.Select(B => (char)B).ToArray());
wrappedE.Data.Add("source", originalHtml);
throw wrappedE;
}
}
while (currentNode.Parent != null)
currentNode = currentNode.Parent;
return currentNode.Nodes();
}
static XElement FindParentOfNewNode(Majestic12.HTMLchunk m12chunk, string originalHtml, XElement nextPotentialParent) {
string m12chunkCleanedTag = CleanupTagName(m12chunk.sTag, originalHtml);
XElement discoveredParent = null;
// Get a list of all ancestors
List<XElement> ancestors = new List<XElement>();
XElement ancestor = nextPotentialParent;
while (ancestor != null) {
ancestors.Add(ancestor);
ancestor = ancestor.Parent;
}
// Check if the new tag implies a previous tag was closed.
if ("form" == m12chunkCleanedTag) {
discoveredParent = ancestors
.Where(XE => m12chunkCleanedTag == XE.Name)
.Take(1)
.Select(XE => XE.Parent)
.FirstOrDefault();
}
else if ("td" == m12chunkCleanedTag) {
discoveredParent = ancestors
.TakeWhile(XE => "tr" != XE.Name)
.Where(XE => m12chunkCleanedTag == XE.Name)
.Take(1)
.Select(XE => XE.Parent)
.FirstOrDefault();
}
else if ("tr" == m12chunkCleanedTag) {
discoveredParent = ancestors
.TakeWhile(XE => !("table" == XE.Name
|| "thead" == XE.Name
|| "tbody" == XE.Name
|| "tfoot" == XE.Name))
.Where(XE => m12chunkCleanedTag == XE.Name)
.Take(1)
.Select(XE => XE.Parent)
.FirstOrDefault();
}
else if ("thead" == m12chunkCleanedTag
|| "tbody" == m12chunkCleanedTag
|| "tfoot" == m12chunkCleanedTag) {
discoveredParent = ancestors
.TakeWhile(XE => "table" != XE.Name)
.Where(XE => m12chunkCleanedTag == XE.Name)
.Take(1)
.Select(XE => XE.Parent)
.FirstOrDefault();
}
return discoveredParent ?? nextPotentialParent;
}
static string CleanupTagName(string originalName, string originalHtml) {
string tagName = originalName;
tagName = tagName.TrimStart(new char[] { '?' }); // for nodes <?xml >
if (tagName.Contains(':'))
tagName = tagName.Substring(tagName.LastIndexOf(':') + 1);
return tagName;
}
static readonly Regex _startsAsNumeric = new Regex(@"^[0-9]", RegexOptions.Compiled);
static bool TryCleanupAttributeName(string originalName, ref int xmlnsIndex, out string result) {
result = null;
string attributeName = originalName;
if (string.IsNullOrEmpty(originalName))
return false;
if (_startsAsNumeric.IsMatch(originalName))
return false;
//
// transform xmlns attributes so they don't actually create any XML namespaces
//
if (attributeName.ToLower().Equals("xmlns")) {
attributeName = "xmlns_" + xmlnsIndex.ToString(); ;
xmlnsIndex++;
}
else {
if (attributeName.ToLower().StartsWith("xmlns:")) {
attributeName = "xmlns_" + attributeName.Substring("xmlns:".Length);
}
//
// trim trailing \"
//
attributeName = attributeName.TrimEnd(new char[] { '\"' });
attributeName = attributeName.Replace(":", "_");
}
result = attributeName;
return true;
}
static Regex _weirdTag = new Regex(@"^<!\[.*\]>$"); // matches "<![if !supportEmptyParas]>"
static Regex _aspnetPrecompiled = new Regex(@"^<%.*%>$"); // matches "<%@ ... %>"
static Regex _shortHtmlComment = new Regex(@"^<!-.*->$"); // matches "<!-Extra_Images->"
static XElement ParseTagNode(Majestic12.HTMLchunk m12chunk, string originalHtml, ref int xmlnsIndex) {
if (string.IsNullOrEmpty(m12chunk.sTag)) {
if (m12chunk.sParams.Length > 0 && m12chunk.sParams[0].ToLower().Equals("doctype"))
return new XElement("doctype");
if (_weirdTag.IsMatch(originalHtml))
return new XElement("REMOVED_weirdBlockParenthesisTag");
if (_aspnetPrecompiled.IsMatch(originalHtml))
return new XElement("REMOVED_ASPNET_PrecompiledDirective");
if (_shortHtmlComment.IsMatch(originalHtml))
return new XElement("REMOVED_ShortHtmlComment");
// Nodes like "<br <br>" will end up with a m12chunk.sTag==""... We discard these nodes.
return null;
}
string tagName = CleanupTagName(m12chunk.sTag, originalHtml);
XElement result = new XElement(tagName);
List<XAttribute> attributes = new List<XAttribute>();
for (int i = 0; i < m12chunk.iParams; i++) {
if (m12chunk.sParams[i] == "<!--") {
// an HTML comment was embedded within a tag. This comment and its contents
// will be interpreted as attributes by Majestic-12... skip this attributes
for (; i < m12chunk.iParams; i++) {
if (m12chunk.sTag == "--" || m12chunk.sTag == "-->")
break;
}
continue;
}
if (m12chunk.sParams[i] == "?" && string.IsNullOrEmpty(m12chunk.sValues[i]))
continue;
string attributeName = m12chunk.sParams[i];
if (!TryCleanupAttributeName(attributeName, ref xmlnsIndex, out attributeName))
continue;
attributes.Add(new XAttribute(attributeName, m12chunk.sValues[i]));
}
// If attributes are duplicated with different values, we complain.
// If attributes are duplicated with the same value, we remove all but 1.
var duplicatedAttributes = attributes.GroupBy(A => A.Name).Where(G => G.Count() > 1);
foreach (var duplicatedAttribute in duplicatedAttributes) {
if (duplicatedAttribute.GroupBy(DA => DA.Value).Count() > 1)
throw new Exception("Attribute value was given different values");
attributes.RemoveAll(A => A.Name == duplicatedAttribute.Key);
attributes.Add(duplicatedAttribute.First());
}
result.Add(attributes);
return result;
}
static HTMLparser OpenParser() {
HTMLparser oP = new HTMLparser();
// The code+comments in this function are from the Majestic-12 sample documentation.
// ...
// This is optional, but if you want high performance then you may
// want to set chunk hash mode to FALSE. This would result in tag params
// being added to string arrays in HTMLchunk object called sParams and sValues, with number
// of actual params being in iParams. See code below for details.
//
// When TRUE (and its default) tag params will be added to hashtable HTMLchunk (object).oParams
oP.SetChunkHashMode(false);
// if you set this to true then original parsed HTML for given chunk will be kept -
// this will reduce performance somewhat, but may be desireable in some cases where
// reconstruction of HTML may be necessary
oP.bKeepRawHTML = false;
// if set to true (it is false by default), then entities will be decoded: this is essential
// if you want to get strings that contain final representation of the data in HTML, however
// you should be aware that if you want to use such strings into output HTML string then you will
// need to do Entity encoding or same string may fail later
oP.bDecodeEntities = true;
// we have option to keep most entities as is - only replace stuff like
// this is called Mini Entities mode - it is handy when HTML will need
// to be re-created after it was parsed, though in this case really
// entities should not be parsed at all
oP.bDecodeMiniEntities = true;
if (!oP.bDecodeEntities && oP.bDecodeMiniEntities)
oP.InitMiniEntities();
// if set to true, then in case of Comments and SCRIPT tags the data set to oHTML will be
// extracted BETWEEN those tags, rather than include complete RAW HTML that includes tags too
// this only works if auto extraction is enabled
oP.bAutoExtractBetweenTagsOnly = true;
// if true then comments will be extracted automatically
oP.bAutoKeepComments = true;
// if true then scripts will be extracted automatically:
oP.bAutoKeepScripts = true;
// if this option is true then whitespace before start of tag will be compressed to single
// space character in string: " ", if false then full whitespace before tag will be returned (slower)
// you may only want to set it to false if you want exact whitespace between tags, otherwise it is just
// a waste of CPU cycles
oP.bCompressWhiteSpaceBeforeTag = true;
// if true (default) then tags with attributes marked as CLOSED (/ at the end) will be automatically
// forced to be considered as open tags - this is no good for XML parsing, but I keep it for backwards
// compatibility for my stuff as it makes it easier to avoid checking for same tag which is both closed
// or open
oP.bAutoMarkClosedTagsWithParamsAsOpen = false;
return oP;
}
}
}
- Frank Schwieterman
3
1顺便提一下，HtmlAgilityPack在过去的使用中表现良好，但我更喜欢LINQ。 - Frank Schwieterman
当您添加LINQ转换时，性能如何？ 您有没有想法它与HtmlAgilityPack相比如何？ - user29439
我从未进行过性能比较。现在我使用HtmlAgilityPack，麻烦少多了。不幸的是，上面的代码有很多特殊情况，我没有写测试，所以我无法真正维护它。 - Frank Schwieterman
7
之前提到过Html Agility Pack-如果你追求速度，也可以尝试使用Majestic-12 HTML解析器。虽然它的处理方式有些笨拙，但是它可以提供非常快速的解析体验。
- Grimtron
2
没有第三方库，可以在控制台和Asp.net上运行的WebBrowser类解决方案
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Threading;
class ParseHTML
{
public ParseHTML() { }
private string ReturnString;
public string doParsing(string html)
{
Thread t = new Thread(TParseMain);
t.ApartmentState = ApartmentState.STA;
t.Start((object)html);
t.Join();
return ReturnString;
}
private void TParseMain(object html)
{
WebBrowser wbc = new WebBrowser();
wbc.DocumentText = "feces of a dummy"; //;magic words
HtmlDocument doc = wbc.Document.OpenNew(true);
doc.Write((string)html);
this.ReturnString = doc.Body.InnerHtml + " do here something";
return;
}
}
使用方法：
string myhtml = "<HTML><BODY>This is a new HTML document.</BODY></HTML>";
Console.WriteLine("before:" + myhtml);
myhtml = (new ParseHTML()).doParsing(myhtml);
Console.WriteLine("after:" + myhtml);
- majmun
1
我过去使用ZetaHtmlTidy加载随机网站，然后使用xpath (例如/html/body//p[@class='textblock']) 打击内容的各个部分。它效果不错，但也有一些特殊的网站它无法解决，所以我不确定它是绝对最佳的解决方案。
- Rahul
1
解析HTML的问题在于它不是一门精确的科学。如果你要解析的是XHTML，那么事情会变得容易得多（正如你提到的，你可以使用通用的XML解析器）。因为HTML不一定是格式良好的XML，所以你在尝试解析它时会遇到很多问题。这几乎需要根据每个网站进行处理。
- Mark Ingram
3
1将HTML解析为W3C规定的XHTML格式难道不是一门精确科学吗？ - pupeno
应该这样做，但人们并没有这么做。 - Dominic K
@J. Pablo 不过并不容易（这也是需要库的原因:p）...例如，在HTML4/5下，<p>标签不需要显式关闭。天哪！ - user166390
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