ASP.NET试图从字符串中剥离html

问题描述

| 因此，我有一个cms，用户可以通过cuteeditor输入内容，该命令可以正常工作，然后在我的网站上显示此数据。很少发生但令人讨厌的一件事是用户在其文本中输入某些标记，这使得该字体看起来与页面上的其他字体不同，即

<span style=\"font-size: 11pt\">Special Olympics Ireland provides year round sports training and athletic competition&nbsp;in a variety of Olympic&nbsp;type sports&nbsp;for persons with&nbsp;intellectual&nbsp;disabilities&nbsp;in </span><span style=\"font-size: 11pt\">Ireland</span><span style=\"font-size: 11pt\"> and </span><span style=\"font-size: 11pt\">Northern Ireland</span><span style=\"font-size: 11pt\"> in accordance with and furtherance of the mission,goal and founding principles of the international Special Olympics movement.</span>

基本上我想做的是

String.Replace(\"<span style=\"font-size: 11pt\">\",\"\")

但是，当然，下一次他们只能使用8、9或10的字体大小时，只能捕获上述情况，因此filter方法必须像这样聪明。有任何想法吗？所以目前我有类似 testSpan = Regex.Replace（testSpan，@ \“ \\ s] +）？）+ \\ s * | \\ s *）/？> \”，String.Empty）; 但是它基本上摆脱了所有的html我只是想摆脱标签

解决方法

如果要遵循StackOverflow的示例，则可以创建允许的HTML标签的白名单，然后删除其余部分。以下是Jeff Atwood用于清理和平衡StackOverflow用户生成的内容中的HTML标签的代码段。清理http://refactormycode.com/codes/333-sanitize-html 平衡http://refactormycode.com/codes/360-balance-html-tags 允许标签的列表https://meta.stackexchange.com/questions/1777/what-html-tags-are-allowed 更新资料看起来Refactormycode已死。这是我在此之前捕获的一些代码：

/// <summary>
/// Provides some static extension methods for processing strings with HTML in them.
/// </summary>
public static class HtmlStripper
{
    #region Sanitize

    private static readonly Regex Tags = new Regex(\"<[^>]*(>|$)\",RegexOptions.Singleline | RegexOptions.ExplicitCapture |
        RegexOptions.Compiled);

    private static readonly Regex Whitelist =
        new Regex(
            @\"
^</?(b(lockquote)?|code|d(d|t|l|el)|em|h(1|2|3)|i|kbd|li|ol|p(re)?|s(ub|up|trong|trike)?|ul)>$|
^<(b|h)r\\s?/?>$\",RegexOptions.Singleline | RegexOptions.ExplicitCapture | RegexOptions.Compiled |
            RegexOptions.IgnorePatternWhitespace);

    private static readonly Regex WhitelistA =
        new Regex(
            @\"
^<a\\s
href=\"\"(\\#\\d+|(https?|ftp)://[-a-z0-9+&@#/%?=~_|!:,.;\\(\\)]+)\"\"
(\\stitle=\"\"[^\"\"<>]+\"\")?(\\starget=\"\"[^\"\"<>]+\"\")?\\s?>$|
^</a>$\",RegexOptions.Singleline | RegexOptions.ExplicitCapture | RegexOptions.Compiled |
            RegexOptions.IgnorePatternWhitespace);

    private static readonly Regex WhitelistImg =
        new Regex(
            @\"
^<img\\s
src=\"\"https?://[-a-z0-9+&@#/%?=~_|!:,.;\\(\\)]+\"\"
(\\swidth=\"\"\\d{1,3}\"\")?
(\\sheight=\"\"\\d{1,3}\"\")?
(\\salt=\"\"[^\"\"<>]*\"\")?
(\\stitle=\"\"[^\"\"<>]*\"\")?
\\s?/?>$\",RegexOptions.Singleline | RegexOptions.ExplicitCapture | RegexOptions.Compiled |
            RegexOptions.IgnorePatternWhitespace);


    /// <summary>
    /// sanitize any potentially dangerous tags from the provided raw HTML input using 
    /// a whitelist based approach,leaving the \"safe\" HTML tags
    /// CODESNIPPET:4100A61A-1711-4366-B0B0-144D1179A937
    /// </summary>
    /// <remarks>
    /// Based on Jeff Atwood\'s code,found at http://refactormycode.com/codes/333-sanitize-html
    /// Since Jeff Atwood is StackOverflow\'s administrator,this is most likely the code used by
    /// that site. See http://meta.stackoverflow.com/questions/1777/what-html-tags-are-allowed
    /// for a list of allowed tags.
    /// </remarks>
    public static string SanitizeHtml(string html)
    {
        if (String.IsNullOrEmpty(html)) return html;

        // match every HTML tag in the input
        MatchCollection tags = Tags.Matches(html);
        for (int i = tags.Count - 1; i > -1; i--)
        {
            Match tag = tags[i];
            string tagname = tag.Value.ToLowerInvariant();

            if (!(Whitelist.IsMatch(tagname) || WhitelistA.IsMatch(tagname) || WhitelistImg.IsMatch(tagname)))
            {
                html = html.Remove(tag.Index,tag.Length);
            }
        }

        return html;
    }

    #endregion

    #region Balance tags

    private static readonly Regex Namedtags = new Regex
        (@\"</?(?<tagname>\\w+)[^>]*(\\s|$|>)\",RegexOptions.Singleline | RegexOptions.ExplicitCapture | RegexOptions.Compiled);

    /// <summary>
    /// attempt to balance HTML tags in the html string
    /// by removing any unmatched opening or closing tags
    /// IMPORTANT: we *assume* HTML has *already* been 
    /// sanitized and is safe/sane before balancing!
    /// 
    /// CODESNIPPET: A8591DBA-D1D3-11DE-947C-BA5556D89593
    /// </summary>
    /// <remarks>
    /// From Jeff Atwood\'s post at 
    /// http://refactormycode.com/codes/360-balance-html-tags
    /// </remarks>
    public static string BalanceTags(string html)
    {
        if (String.IsNullOrEmpty(html)) return html;

        // convert everything to lower case; this makes
        // our case insensitive comparisons easier
        MatchCollection tags = Namedtags.Matches(html.ToLowerInvariant());

        // no HTML tags present? nothing to do; exit now
        int tagcount = tags.Count;
        if (tagcount == 0) return html;

        const string ignoredtags = \"<p><img><br><li><hr>\";
        var tagpaired = new bool[tagcount];
        var tagremove = new bool[tagcount];

        // loop through matched tags in forward order
        for (int ctag = 0; ctag < tagcount; ctag++)
        {
            string tagname = tags[ctag].Groups[\"tagname\"].Value;

            // skip any already paired tags
            // and skip tags in our ignore list; assume they\'re self-closed
            if (tagpaired[ctag] || ignoredtags.Contains(\"<\" + tagname + \">\")) continue;

            string tag = tags[ctag].Value;
            int match = -1;

            if (tag.StartsWith(\"</\"))
            {
                // this is a closing tag
                // search backwards (previous tags),look for opening tags
                for (int ptag = ctag - 1; ptag >= 0; ptag--)
                {
                    string prevtag = tags[ptag].Value;
                    if (!tagpaired[ptag] && prevtag.Equals(\"<\" + tagname,StringComparison.InvariantCulture))
                    {
                        // minor optimization; we do a simple possibly incorrect match above
                        // the start tag must be <tag> or <tag{space} to match
                        if (prevtag.StartsWith(\"<\" + tagname + \">\") || prevtag.StartsWith(\"<\" + tagname + \" \"))
                        {
                            match = ptag;
                            break;
                        }
                    }
                }
            }
            else
            {
                // this is an opening tag
                // search forwards (next tags),look for closing tags
                for (int ntag = ctag + 1; ntag < tagcount; ntag++)
                {
                    if (!tagpaired[ntag] &&
                        tags[ntag].Value.Equals(\"</\" + tagname + \">\",StringComparison.InvariantCulture))
                    {
                        match = ntag;
                        break;
                    }
                }
            }

            // we tried,regardless,if we got this far
            tagpaired[ctag] = true;
            if (match == -1) tagremove[ctag] = true; // mark for removal
            else tagpaired[match] = true; // mark paired
        }

        // loop through tags again,this time in reverse order
        // so we can safely delete all orphaned tags from the string
        for (int ctag = tagcount - 1; ctag >= 0; ctag--)
        {
            if (tagremove[ctag])
            {
                html = html.Remove(tags[ctag].Index,tags[ctag].Length);
            }
        }

        return html;
    }

    #endregion
}

, 对于这种事情，您实际上应该使用适当的HTML解析器。 , 这是我用来从VB.NET中的字符串中剥离HTML的函数：

Public Shared Function StripHTML(ByVal htmlString As String) As String
     Dim pattern As String = \"<(.|\\n)*?>\"
     Return Regex.Replace(htmlString,pattern,String.Empty)
End Function

希望能帮助到你 , 对于这种特定情况，您可以执行以下操作

   String input = @\"<span style=\"\"font-size: 11pt\"\">Special Olympics Ireland provides year round sports training and athletic competition&nbsp;in a variety of Olympic&nbsp;type sports&nbsp;for persons with&nbsp;intellectual&nbsp;disabilities&nbsp;in </span><span style=\"\"font-size: 11pt\"\">Ireland</span><span style=\"\"font-size: 11pt\"\"> and </span><span style=\"\"font-size: 11pt\"\">Northern Ireland</span><span style=\"\"font-size: 11pt\"\"> in accordance with and furtherance of the mission,goal and founding principles of the international Special Olympics movement.</span>\";
   var element = XElement.Parse(input.Replace(\"&nbsp;\",\" \"));
   string stripped = element.Value;

但通常您不希望直接在html上处理任何类型的字符串操作或解析。最好使用其他答案中指出的解析器。

asp.net html 剥离字符串字符串试图

ASP.NET试图从字符串中剥离html

问题描述

解决方法

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