HTML敏捷性包带标签NOT IN白名单 [英] HTML Agility Pack strip tags NOT IN whitelist
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问题描述
我试图创建一个函数从而消除HTML标签，哪些不在白名单中的属性。
我有以下HTML：
I'm trying to create a function which removes html tags and attributes which are not in a white list. I have the following HTML:
<b>first text </b>
<b>second text here
<a>some text here</a>
<a>some text here</a>
</b>
<a>some twxt here</a>
我使用的HTML敏捷包和code我至今是：
I am using HTML agility pack and the code I have so far is:
static List<string> WhiteNodeList = new List<string> { "b" };
static List<string> WhiteAttrList = new List<string> { };
static HtmlNode htmlNode;
public static void RemoveNotInWhiteList(out string _output, HtmlNode pNode, List<string> pWhiteList, List<string> attrWhiteList)
{
// remove all attributes not on white list
foreach (var item in pNode.ChildNodes)
{
item.Attributes.Where(u => attrWhiteList.Contains(u.Name) == false).ToList().ForEach(u => RemoveAttribute(u));
}
// remove all html and their innerText and attributes if not on whitelist.
//pNode.ChildNodes.Where(u => pWhiteList.Contains(u.Name) == false).ToList().ForEach(u => u.Remove());
//pNode.ChildNodes.Where(u => pWhiteList.Contains(u.Name) == false).ToList().ForEach(u => u.ParentNode.ReplaceChild(ConvertHtmlToNode(u.InnerHtml),u));
//pNode.ChildNodes.Where(u => pWhiteList.Contains(u.Name) == false).ToList().ForEach(u => u.Remove());
for (int i = 0; i < pNode.ChildNodes.Count; i++)
{
if (!pWhiteList.Contains(pNode.ChildNodes[i].Name))
{
HtmlNode _newNode = ConvertHtmlToNode(pNode.ChildNodes[i].InnerHtml);
pNode.ChildNodes[i].ParentNode.ReplaceChild(_newNode, pNode.ChildNodes[i]);
if (pNode.ChildNodes[i].HasChildNodes && !string.IsNullOrEmpty(pNode.ChildNodes[i].InnerText.Trim().Replace("\r\n", "")))
{
HtmlNode outputNode1 = pNode.ChildNodes[i];
for (int j = 0; j < pNode.ChildNodes[i].ChildNodes.Count; j++)
{
string _childNodeOutput;
RemoveNotInWhiteList(out _childNodeOutput,
pNode.ChildNodes[i], WhiteNodeList, WhiteAttrList);
pNode.ChildNodes[i].ReplaceChild(ConvertHtmlToNode(_childNodeOutput), pNode.ChildNodes[i].ChildNodes[j]);
i++;
}
}
}
}
// Console.WriteLine(pNode.OuterHtml);
_output = pNode.OuterHtml;
}
private static void RemoveAttribute(HtmlAttribute u)
{
u.Value = u.Value.ToLower().Replace("javascript", "");
u.Remove();
}
public static HtmlNode ConvertHtmlToNode(string html)
{
HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
doc.LoadHtml(html);
if (doc.DocumentNode.ChildNodes.Count == 1)
return doc.DocumentNode.ChildNodes[0];
else return doc.DocumentNode;
}
我tryig实现的输出是
The output I am tryig to achieve is
<b>first text </b>
<b>second text here
some text here
some text here
</b>
some twxt here
这意味着，我只是想保持＆LT; B＆GT; 标签结果
究其原因我这样做是因为有些用户执行从MS WORD cpoy粘贴到纽约WYSYWYG HTML编辑器。
That means that I only want to keep the <b> tags.
The reason i'm doing this is because Some of the users do cpoy-paste from MS WORD into ny WYSYWYG html editor.
谢谢！
推荐答案
嘿，显然我几乎发现在博客中有人做....答案
heh, apparently I ALMOST found an answer in a blog post someone made....
using System.Collections.Generic;
using System.Linq;
using HtmlAgilityPack;
namespace Wayloop.Blog.Core.Markup
{
public static class HtmlSanitizer
{
private static readonly IDictionary<string, string[]> Whitelist;
static HtmlSanitizer()
{
Whitelist = new Dictionary<string, string[]> {
{ "a", new[] { "href" } },
{ "strong", null },
{ "em", null },
{ "blockquote", null },
};
}
public static string Sanitize(string input)
{
var htmlDocument = new HtmlDocument();
htmlDocument.LoadHtml(input);
SanitizeNode(htmlDocument.DocumentNode);
return htmlDocument.DocumentNode.WriteTo().Trim();
}
private static void SanitizeChildren(HtmlNode parentNode)
{
for (int i = parentNode.ChildNodes.Count - 1; i >= 0; i--) {
SanitizeNode(parentNode.ChildNodes[i]);
}
}
private static void SanitizeNode(HtmlNode node)
{
if (node.NodeType == HtmlNodeType.Element) {
if (!Whitelist.ContainsKey(node.Name)) {
node.ParentNode.RemoveChild(node);
return;
}
if (node.HasAttributes) {
for (int i = node.Attributes.Count - 1; i >= 0; i--) {
HtmlAttribute currentAttribute = node.Attributes[i];
string[] allowedAttributes = Whitelist[node.Name];
if (!allowedAttributes.Contains(currentAttribute.Name)) {
node.Attributes.Remove(currentAttribute);
}
}
}
}
if (node.HasChildNodes) {
SanitizeChildren(node);
}
}
}
}
我HtmlSanitizer从这里
显然，它不会剥离th标签，但是移除元素altoghether。
I got HtmlSanitizer from here Apparently it does not strip th tags, but removes the element altoghether.
OK，这里是解决方案为那些谁以后会需要它。
OK, here is the solution for those who will need it later.
public static class HtmlSanitizer
{
private static readonly IDictionary<string, string[]> Whitelist;
private static List<string> DeletableNodesXpath = new List<string>();
static HtmlSanitizer()
{
Whitelist = new Dictionary<string, string[]> {
{ "a", new[] { "href" } },
{ "strong", null },
{ "em", null },
{ "blockquote", null },
{ "b", null},
{ "p", null},
{ "ul", null},
{ "ol", null},
{ "li", null},
{ "div", new[] { "align" } },
{ "strike", null},
{ "u", null},
{ "sub", null},
{ "sup", null},
{ "table", null },
{ "tr", null },
{ "td", null },
{ "th", null }
};
}
public static string Sanitize(string input)
{
if (input.Trim().Length < 1)
return string.Empty;
var htmlDocument = new HtmlDocument();
htmlDocument.LoadHtml(input);
SanitizeNode(htmlDocument.DocumentNode);
string xPath = HtmlSanitizer.CreateXPath();
return StripHtml(htmlDocument.DocumentNode.WriteTo().Trim(), xPath);
}
private static void SanitizeChildren(HtmlNode parentNode)
{
for (int i = parentNode.ChildNodes.Count - 1; i >= 0; i--)
{
SanitizeNode(parentNode.ChildNodes[i]);
}
}
private static void SanitizeNode(HtmlNode node)
{
if (node.NodeType == HtmlNodeType.Element)
{
if (!Whitelist.ContainsKey(node.Name))
{
if (!DeletableNodesXpath.Contains(node.Name))
{
//DeletableNodesXpath.Add(node.Name.Replace("?",""));
node.Name = "removeableNode";
DeletableNodesXpath.Add(node.Name);
}
if (node.HasChildNodes)
{
SanitizeChildren(node);
}
return;
}
if (node.HasAttributes)
{
for (int i = node.Attributes.Count - 1; i >= 0; i--)
{
HtmlAttribute currentAttribute = node.Attributes[i];
string[] allowedAttributes = Whitelist[node.Name];
if (allowedAttributes != null)
{
if (!allowedAttributes.Contains(currentAttribute.Name))
{
node.Attributes.Remove(currentAttribute);
}
}
else
{
node.Attributes.Remove(currentAttribute);
}
}
}
}
if (node.HasChildNodes)
{
SanitizeChildren(node);
}
}
private static string StripHtml(string html, string xPath)
{
HtmlDocument htmlDoc = new HtmlDocument();
htmlDoc.LoadHtml(html);
if (xPath.Length > 0)
{
HtmlNodeCollection invalidNodes = htmlDoc.DocumentNode.SelectNodes(@xPath);
foreach (HtmlNode node in invalidNodes)
{
node.ParentNode.RemoveChild(node, true);
}
}
return htmlDoc.DocumentNode.WriteContentTo(); ;
}
private static string CreateXPath()
{
string _xPath = string.Empty;
for (int i = 0; i < DeletableNodesXpath.Count; i++)
{
if (i != DeletableNodesXpath.Count - 1)
{
_xPath += string.Format("//{0}|", DeletableNodesXpath[i].ToString());
}
else _xPath += string.Format("//{0}", DeletableNodesXpath[i].ToString());
}
return _xPath;
}
}
我改名为节点，因为如果我不得不解析XML命名空间节点，将在XPath的解析崩溃。
I renamed the node because if I had to parse an XML namespace node it would crash on the xpath parsing.
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