How unescape RFC 3986 string

Question

I've a RFC 3986 encoded string in the form %x##. For example the space character is encoded as %x20 instead of %20. How can I decode it in C#? Using the decode method of Uri, HttpUtility or WebUtility classes the string was not decoded.

does this help: https://stackoverflow.com/questions/846487/how-to-get-uri-escapedatastring-to-comply-with-rfc-3986. its a possible duplicate — Gauravsa, Jan 09 '20 at 10:18
A space (ascii 20) was not allowed so it was replaced with the encoded string. — jdweng, Jan 09 '20 at 10:21

score 1 · Accepted Answer · answered Jan 09 '20 at 10:36

1

You can try regular expressions in order to Replace all %x## as well as %## matches:

  using System.Text.RegularExpressions;

  ...

  string demo = "abc%x20def%20pqr";

  string result = Regex.Replace(
      demo, 
    "%x?([0-9A-F]{2})", 
      m => ((char)Convert.ToInt32(m.Groups[1].Value, 16)).ToString(), 
      RegexOptions.IgnoreCase);

  Console.Write(result);

Outcome:

  abc def pqr

answered Jan 09 '20 at 10:36

Dmitry Bychenko

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is there not any standard .NET method that do this? – Matteo Jan 09 '20 at 10:59
@Matteo: it seems that we have to implement `%x##` case manually; `Uri.UnescapeDataString()` is ok for `%##` escapements – Dmitry Bychenko Jan 09 '20 at 11:06

score 0 · Answer 2 · answered Jan 09 '20 at 11:08

You can try something like this: You can try:

Reference: How to get Uri.EscapeDataString to comply with RFC 3986

    var escapedString = new StringBuilder(Uri.EscapeDataString(value));

    for (int i = 0; i < UriRfc3986CharsToEscape.Length; i++) {
        escapedString.Replace(UriRfc3986CharsToEscape[i], Uri.HexEscape(UriRfc3986CharsToEscape[i][0]));
    }

    // Return the fully-RFC3986-escaped string.
    return escaped.ToString();

How unescape RFC 3986 string

2 Answers2