UrlEncodeUnicode and browser navigation errors

Question

I want to redirect a request to some URL that may or may not contain non-ascii characters (e.g. german umlauts).

Doing this with the relevant part of the URL:

var url = HttpUtility.UrlEncodeUnicode("öäü.pdf"); // -> "%u00f6%u00e4%u00fc.pdf"

and then issuing the redirect:

Response.Redirect(url, ...);

will not produce the desired behaviour. It appears, the browser (IE, Opera as far as I have tested) doesn't honor this command when the URL to redirect to is Unicode-encoded. Ordinary UrlEncode'd paths work fine.

I have tried setting this in the Web.Config:

<configuration>
  <system.web>
    <globalization
      requestEncoding="utf-8"
      responseEncoding="utf-8"
    />
  </system.web>
</configuration>

That didn't change a thing.

Is there anything I can do, to get this to work?

Answer 1

I am not sure with question, but could you try with this?

HttpUtility.UrlEncode("öäü.pdf")

or

HttpUtility.UrlEncode("öäü.pdf", Encoding.UTF8)

Sorry, If I understand your question wrong way.

Answer 2

It produces strings that contain two %.. sequences for every double-byte character as opposed to a single %u.... sequence when using UrlEncodeUnicode(...). Any idea why this is?

Because UTF-8 uses multiple bytes to represent non-ASCII characters and each byte is URL-encoded separately. This is the standard way to encode Unicode in URI, as used by IRI and by default in all modern web browsers.

UrlEncodeUnicode and %u00f6, on the other hand, is totally spurious nonsense that should not be used for anything, and has been put there only to confuse you.