The Super Pool Framework

// -----
// Copyright 2010 Deyan Timnev
// This file is part of the Matrix Platform (www.matrixplatform.com).
// The Matrix Platform is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, 
// either version 3 of the License, or (at your option) any later version. The Matrix Platform is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
// without even the implied warranty of  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
// You should have received a copy of the GNU Lesser General Public License along with the Matrix Platform. If not, see http://www.gnu.org/licenses/lgpl.html
// -----
using System;
using System.Collections.Generic;
using System.Text;
using System.Globalization;

namespace Matrix.Common.Core
{
    /// <summary>
    /// Contains a couple of methods that replace the System.Web methods
    /// with the same names, thus making us free of referencing System.Web.
    /// </summary>
    public static class WebHelper
    {
        /// <summary>
        /// *IMPORTANT* this functionality is not complete.
        /// </summary>
        public static string HtmlDecode(string input)
        {
            // Replace special HTML symbols.
            input = input.Replace("&lt;", "<");
            input = input.Replace("&gt;", ">");
            input = input.Replace("&amp;", "&");
            input = input.Replace("&rsquo;", "\'");
            input = input.Replace("&quot;", "\"");

            input = input.Replace("&reg;", "®");
            input = input.Replace("&copy;", "©");

            input = input.Replace("&nbsp;", " ");
            input = input.Replace("&#39;", "'");

            input = input.Replace("&cent;", "¢");
            input = input.Replace("&pound;", "£");
            input = input.Replace("&yen;", "¥");

            return input;
        }

        /// <summary>
        /// UrlEncodes a string without the requirement for System.Web
        /// </summary>
        /// <param name="String"></param>
        /// <returns></returns>
        // [Obsolete("Use System.Uri.EscapeDataString instead")]
        public static string UrlEncode(string text)
        {
            // Sytem.Uri provides reliable parsing
            return Uri.EscapeDataString(text);
        }

        /// <summary>
        /// UrlDecodes a string without requiring System.Web
        /// </summary>
        /// <param name="text">String to decode.</param>
        /// <returns>decoded string</returns>
        public static string UrlDecode(string text)
        {
            // pre-process for + sign space formatting since System.Uri doesn't handle it
            // plus literals are encoded as %2b normally so this should be safe
            text = text.Replace("+", " ");
            return Uri.UnescapeDataString(text);
        }

        /// <summary>
        /// Retrieves a value by key from a UrlEncoded string.
        /// </summary>
        /// <param name="urlEncoded">UrlEncoded String</param>
        /// <param name="key">Key to retrieve value for</param>
        /// <returns>returns the value or "" if the key is not found or the value is blank</returns>
        public static string GetUrlEncodedKey(string urlEncoded, string key)
        {
            urlEncoded = "&" + urlEncoded + "&";

            int Index = urlEncoded.IndexOf("&" + key + "=", StringComparison.OrdinalIgnoreCase);
            if (Index < 0)
                return "";

            int lnStart = Index + 2 + key.Length;

            int Index2 = urlEncoded.IndexOf("&", lnStart);
            if (Index2 < 0)
                return "";

            return UrlDecode(urlEncoded.Substring(lnStart, Index2 - lnStart));
        }

        /// <summary>
        /// HTML-encodes a string and returns the encoded string.
        /// </summary>
        /// <param name="text">The text string to encode. </param>
        /// <returns>The HTML-encoded text.</returns>
        public static string HtmlEncode(string text)
        {
            if (text == null)
                return null;

            StringBuilder sb = new StringBuilder(text.Length);

            int len = text.Length;
            for (int i = 0; i < len; i++)
            {
                switch (text[i])
                {

                    case '<':
                        sb.Append("&lt;");
                        break;
                    case '>':
                        sb.Append("&gt;");
                        break;
                    case '"':
                        sb.Append("&quot;");
                        break;
                    case '&':
                        sb.Append("&amp;");
                        break;
                    default:
                        if (text[i] > 159)
                        {
                            // decimal numeric entity
                            sb.Append("&#");
                            sb.Append(((int)text[i]).ToString(CultureInfo.InvariantCulture));
                            sb.Append(";");
                        }
                        else
                            sb.Append(text[i]);
                        break;
                }
            }
            return sb.ToString();
        }
    }
}