public static string Unescape(string text)
{
// We only escape an XML-safe subset of the JavaScript escaped characters,
// so we can reverse things correctly using JavaScript's Unescape method.
string result = JavaScriptUtility.Unescape(text);
return(result);
}
public static string Escape(string text)
{
int length = text.Length;
StringBuilder sb = new(2 * length);
for (int i = 0; i < length; i++)
{
char ch = text[i];
if (ch == ' ')
{
// XML attributes will remove leading and trailing spaces and collapse sequences of spaces to a single space.
// We don't want that so we have to encode non-safe spaces. It's a safe space if chars before and after are
// non-spaces. This also encodes "X%20%20Y" when only one of the spaces needs to be encoded, but that's ok.
// See "Attribute-Value Normalization" at https://www.w3.org/TR/REC-xml/#AVNormalize.
if (i > 0 && i < length - 1 && text[i - 1] != ' ' && text[i + 1] != ' ')
{
// A safe space (i.e., surrounded by non-space chars).
sb.Append(ch);
}
else
{
// Either a leading space, a trailing space, or in a sequence of spaces.
sb.Append(JavaScriptUtility.Escape(ch));
}
}
else if (ch != '%' && ch > ' ' && ch <= '~')
{
// Allow any "printable" char except '%' since that's the JavaScript escape char.
sb.Append(ch);
}
else
{
// This will be used for control chars, which are invalid in XML, and for higher Unicode chars.
sb.Append(JavaScriptUtility.Escape(ch));
}
}
string result = sb.ToString();
return(result);
}