diff options
Diffstat (limited to 'src/DotNetOpenAuth.OpenId/Yadis/HtmlParser.cs')
| -rw-r--r-- | src/DotNetOpenAuth.OpenId/Yadis/HtmlParser.cs | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/src/DotNetOpenAuth.OpenId/Yadis/HtmlParser.cs b/src/DotNetOpenAuth.OpenId/Yadis/HtmlParser.cs new file mode 100644 index 0000000..a6b64c1 --- /dev/null +++ b/src/DotNetOpenAuth.OpenId/Yadis/HtmlParser.cs @@ -0,0 +1,142 @@ +//----------------------------------------------------------------------- +// <copyright file="HtmlParser.cs" company="Andrew Arnott, Scott Hanselman, Jason Alexander"> +// Copyright (c) Andrew Arnott, Scott Hanselman, Jason Alexander. All rights reserved. +// </copyright> +//----------------------------------------------------------------------- + +namespace DotNetOpenAuth.Yadis { + using System; + using System.Collections.Generic; + using System.Diagnostics.Contracts; + using System.Globalization; + using System.Linq; + using System.Text; + using System.Text.RegularExpressions; + using System.Web; + using System.Web.UI.HtmlControls; + + /// <summary> + /// An HTML HEAD tag parser. + /// </summary> + internal static class HtmlParser { + /// <summary> + /// Common flags to use on regex tests. + /// </summary> + private const RegexOptions Flags = RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline | RegexOptions.Compiled | RegexOptions.IgnoreCase; + + /// <summary> + /// A regular expression designed to select tags (?) + /// </summary> + private const string TagExpr = "\n# Starts with the tag name at a word boundary, where the tag name is\n# not a namespace\n<{0}\\b(?!:)\n \n# All of the stuff up to a \">\", hopefully attributes.\n(?<attrs>[^>]*?)\n \n(?: # Match a short tag\n />\n \n| # Match a full tag\n >\n \n (?<contents>.*?)\n \n # Closed by\n (?: # One of the specified close tags\n </?{1}\\s*>\n \n # End of the string\n | \\Z\n \n )\n \n)\n "; + + /// <summary> + /// A regular expression designed to select start tags (?) + /// </summary> + private const string StartTagExpr = "\n# Starts with the tag name at a word boundary, where the tag name is\n# not a namespace\n<{0}\\b(?!:)\n \n# All of the stuff up to a \">\", hopefully attributes.\n(?<attrs>[^>]*?)\n \n(?: # Match a short tag\n />\n \n| # Match a full tag\n >\n )\n "; + + /// <summary> + /// A regular expression designed to select attributes within a tag. + /// </summary> + private static readonly Regex attrRe = new Regex("\n# Must start with a sequence of word-characters, followed by an equals sign\n(?<attrname>(\\w|-)+)=\n\n# Then either a quoted or unquoted attribute\n(?:\n\n # Match everything that's between matching quote marks\n (?<qopen>[\"\\'])(?<attrval>.*?)\\k<qopen>\n|\n\n # If the value is not quoted, match up to whitespace\n (?<attrval>(?:[^\\s<>/]|/(?!>))+)\n)\n\n|\n\n(?<endtag>[<>])\n ", Flags); + + /// <summary> + /// A regular expression designed to select the HEAD tag. + /// </summary> + private static readonly Regex headRe = TagMatcher("head", new[] { "body" }); + + /// <summary> + /// A regular expression designed to select the HTML tag. + /// </summary> + private static readonly Regex htmlRe = TagMatcher("html", new string[0]); + + /// <summary> + /// A regular expression designed to remove all comments and scripts from a string. + /// </summary> + private static readonly Regex removedRe = new Regex(@"<!--.*?-->|<!\[CDATA\[.*?\]\]>|<script\b[^>]*>.*?</script>", Flags); + + /// <summary> + /// Finds all the HTML HEAD tag child elements that match the tag name of a given type. + /// </summary> + /// <typeparam name="T">The HTML tag of interest.</typeparam> + /// <param name="html">The HTML to scan.</param> + /// <returns>A sequence of the matching elements.</returns> + public static IEnumerable<T> HeadTags<T>(string html) where T : HtmlControl, new() { + html = removedRe.Replace(html, string.Empty); + Match match = htmlRe.Match(html); + string tagName = (new T()).TagName; + if (match.Success) { + Match match2 = headRe.Match(html, match.Index, match.Length); + if (match2.Success) { + string text = null; + string text2 = null; + Regex regex = StartTagMatcher(tagName); + for (Match match3 = regex.Match(html, match2.Index, match2.Length); match3.Success; match3 = match3.NextMatch()) { + int beginning = (match3.Index + tagName.Length) + 1; + int length = (match3.Index + match3.Length) - beginning; + Match match4 = attrRe.Match(html, beginning, length); + var headTag = new T(); + while (match4.Success) { + if (match4.Groups["endtag"].Success) { + break; + } + text = match4.Groups["attrname"].Value; + text2 = HttpUtility.HtmlDecode(match4.Groups["attrval"].Value); + headTag.Attributes.Add(text, text2); + match4 = match4.NextMatch(); + } + yield return headTag; + } + } + } + } + + /// <summary> + /// Filters a list of controls based on presence of an attribute. + /// </summary> + /// <typeparam name="T">The type of HTML controls being filtered.</typeparam> + /// <param name="sequence">The sequence.</param> + /// <param name="attribute">The attribute.</param> + /// <returns>A filtered sequence of attributes.</returns> + internal static IEnumerable<T> WithAttribute<T>(this IEnumerable<T> sequence, string attribute) where T : HtmlControl { + Contract.Requires<ArgumentNullException>(sequence != null); + Contract.Requires<ArgumentException>(!String.IsNullOrEmpty(attribute)); + return sequence.Where(tag => tag.Attributes[attribute] != null); + } + + /// <summary> + /// Generates a regular expression that will find a given HTML tag. + /// </summary> + /// <param name="tagName">Name of the tag.</param> + /// <param name="closeTags">The close tags (?).</param> + /// <returns>The created regular expression.</returns> + private static Regex TagMatcher(string tagName, params string[] closeTags) { + string text2; + if (closeTags.Length > 0) { + StringBuilder builder = new StringBuilder(); + builder.AppendFormat("(?:{0}", tagName); + int index = 0; + string[] textArray = closeTags; + int length = textArray.Length; + while (index < length) { + string text = textArray[index]; + index++; + builder.AppendFormat("|{0}", text); + } + builder.Append(")"); + text2 = builder.ToString(); + } else { + text2 = tagName; + } + return new Regex(string.Format(CultureInfo.InvariantCulture, TagExpr, tagName, text2), Flags); + } + + /// <summary> + /// Generates a regular expression designed to find a given tag. + /// </summary> + /// <param name="tagName">The tag to find.</param> + /// <returns>The created regular expression.</returns> + private static Regex StartTagMatcher(string tagName) { + return new Regex(string.Format(CultureInfo.InvariantCulture, StartTagExpr, tagName), Flags); + } + } +} |