114 lines
3.2 KiB
C#
114 lines
3.2 KiB
C#
//------------------------------------------------------------------------------
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// <copyright file="RegexWorker.cs" company="Microsoft">
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// Copyright (c) Microsoft Corporation. All rights reserved.
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// </copyright>
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//------------------------------------------------------------------------------
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/*
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* Base class for browser capabilities object: just a read-only dictionary
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* holder that supports Init()
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*
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*
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*/
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using System.Web.UI;
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using System.Collections;
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using System.Collections.Specialized;
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using System.ComponentModel;
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using System.Globalization;
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using System.Security.Permissions;
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using System.Text;
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using System.Text.RegularExpressions;
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using System.Web.RegularExpressions;
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using System.Web.Util;
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namespace System.Web.Configuration {
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//
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public class RegexWorker {
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internal static readonly Regex RefPat = new BrowserCapsRefRegex();
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private Hashtable _groups;
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private HttpBrowserCapabilities _browserCaps;
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public RegexWorker(HttpBrowserCapabilities browserCaps) {
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_browserCaps = browserCaps;
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}
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private string Lookup(string from) {
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MatchCollection matches = RefPat.Matches(from);
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// shortcut for no reference case
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if (matches.Count == 0) {
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return from;
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}
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StringBuilder sb = new StringBuilder();
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int startIndex = 0;
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foreach (Match match in matches) {
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int length = match.Index - startIndex;
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sb.Append(from.Substring(startIndex, length));
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startIndex = match.Index + match.Length;
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string groupName = match.Groups["name"].Value;
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string result = null;
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if (_groups != null) {
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result = (String)_groups[groupName];
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}
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if (result == null) {
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result = _browserCaps[groupName];
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}
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sb.Append(result);
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}
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sb.Append(from, startIndex, from.Length - startIndex);
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string output = sb.ToString();
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// Return null instead of empty string since empty string is used to override values.
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if (output.Length == 0) {
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return null;
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}
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return output;
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}
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public string this[string key] {
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get {
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return Lookup(key);
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}
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}
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public bool ProcessRegex(string target, string regexExpression) {
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if(target == null) {
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target = String.Empty;
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}
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// Adding timeout for Regex in case of malicious string causing DoS
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Regex regex = RegexUtil.CreateRegex(regexExpression, RegexOptions.ExplicitCapture);
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Match match = regex.Match(target);
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if(match.Success == false) {
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return false;
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}
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string[] groups = regex.GetGroupNames();
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if (groups.Length > 0) {
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if (_groups == null) {
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_groups = new Hashtable();
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}
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for (int i = 0; i < groups.Length; i++) {
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_groups[groups[i]] = match.Groups[i].Value;
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}
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}
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return true;
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}
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}
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}
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