Search code examples
javascriptc#encoding

How to properly encode (client) and decode (server) string containing special char such as Non-Breaking Spaces?

I need to safely transmit strings that may contain non-breaking spaces (NBSP, Unicode U+00A0) through security filters like Cloudflare's. Additionally, I'm looking for a method to potentially reduce the payload size for efficiency. The challenge is to ensure these strings not losing their original structure.

Here is the client:

var encoded = window.btoa(encodeURIComponent("SELECT a FROM b"));
//U0VMRUNUJUMyJUEwYSVDMiVBMEZST00lQzIlQTBi

While in reality the "SELECT a FROM b" is "SELECTNBSFaNBSFFROMNBSFb".

And the server side code reproduce this string: SELECT%C2%A0a%C2%A0FROM%C2%A0b while the final should string should the same "SELECT a FROM b".

var valueBytes = Convert.FromBase64String(value);
return Encoding.UTF8.GetString(valueBytes);

How can I modify my server-side code to correctly decode the percent-encoded NBSP (and potentially other characters) back into their original form? Is there a more efficient way to reduce the payload size? (this is less important)

Solution

  • Solved with Uri.UnescapeDataString:

    var valueBytes = Convert.FromBase64String(value);
var decodedString = Encoding.UTF8.GetString(valueBytes);
return Uri.UnescapeDataString(decodedString);