.net 中实现php rawurlencode方法（RFC3986）

在对接api时候，经常需要对字符串进行各种编码处理，系统可能是异构的，实现语言也就可能是不一样的。所以经常会使人犯一些2B的错误！

比如：php实现的api中用了rawurlencode,文档中写，需要对字符串进行urlencode编码，.net的开发人员看到文档，直接使用HttpUtitlity.UrlEncode，

　　　本以为问题已经解决，实际埋下了一个大坑！

　　其实php的rawurlincode 实现的是RFC3986，.NET(c#)的HttpUtility.UrlEncode实现的并不是RFC3986!所以对同一个字符串编码当然可能产生不同的结果！

关键是这种问题，很难意识到并去解决！所以，以后遇到类似的问题，一定要记得：要面向协议思考、解决问题，否则...

　　下面附上C#对RFC3986的实现：

　　 /// <summary>
/// Provides implementation of RFC3986 Percent Encoding mechanism.
/// </summary>
public class RFC3986Encoder
{
/// <summary>
/// Performs upper case percent encoding against the specified <paramref name="input"/>.
/// </summary>
/// <param name="input">The string to encode.</param>
/// <returns>Encode string.</returns>
public static string Encode(string input)
{
if (string.IsNullOrEmpty(input))
return input;

StringBuilder newStr = new StringBuilder();

foreach (var item in input)
{
if (IsReverseChar(item))
{
newStr.Append("%");
var temp = ((int)item).ToString("X2");
newStr.Append(temp);
}
else
newStr.Append(item);
}

return newStr.ToString();
}

/// <summary>
/// Performs lower case percent encoding (url-encodes) on the <paramref name="input"/> as what HttpUtility.UrlEncode does.
/// </summary>
/// <param name="input">The string to encode.</param>
/// <returns>Encode string.</returns>
public static string UrlEncode(string input)
{
StringBuilder newBytes = new StringBuilder();
var urf8Bytes = Encoding.UTF8.GetBytes(input);
foreach (var item in urf8Bytes)
{
if (IsReverseChar((char)item))
{
newBytes.Append('%');
newBytes.Append(ByteToHex(item));

}
else
newBytes.Append((char)item);
}

return newBytes.ToString();
}

private static bool IsReverseChar(char c)
{
return !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9')
|| c == '-' || c == '_' || c == '.' || c == '~');
}

private static string ByteToHex(byte b)
{
return b.ToString("x2");
}

private static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, 0);

/// <summary>
/// Gets the seconds from 1970/1/1.
/// </summary>
/// <param name="time">The time to calculate from.</param>
/// <returns>The seconds.</returns>
public static int ToUnixTime(DateTime time)
{
return (int)(time.ToUniversalTime() - UnixEpoch).TotalSeconds;
}
}