Getting U+fffd/65533 instead of special character from Query String

Question

I have a C# .net web project that have a globalization tag set to:

Answer 1

The problem comes from the combination Firefox/Asp.Net. When you manually entered a URL in Firefox's address bar, if the url contains french or swedish characters, Firefox will encode the url with "ISO-8859-1" by default.

But when asp.net recieves such a url, it thinks that it's utf-8 encoded ... And encoded characters become "U+fffd". I couldn't find a way in asp.net to detect that the url is "ISO-8859-1". Request.Encoding is set to utf-8 ... :(

Several solutions exist :

• put in your Web.config. But your may comme with other problems, and your application won't be standard anymore (it will not work with languages like japanese) ... And anyway, I prefer using UTF-8 !

• go to about:config in Firefox and set the value of network.standard-url.encode-query-utf8 to true. It will now work for you (Firefox will encode all your url with utf-8). But not for anybody else ...

• The least worst solution I could come with was to handle this with code. If the default decoding didn't work, we reparse QueryString with iso8859-1 :

  string query = Request.QueryString["search"];
  if (query.Contains("%ufffd"))
      query = HttpUtility.ParseQueryString(Request.Url.Query, Encoding.GetEncoding("iso-8859-1"))["search"];
  query = HttpUtility.UrlDecode(query);
  

It works with hyperlinks and manually-entered url, in french, english, or japanese. But I don't know how it will handle other encodings like ISO8859-5 (russian) ...

Does anyone have a better solution ?

This solves only the problem of manually-entered url. In your hyperlinks, don't forget to encode url parameters with HttpUtility.UrlEncode on the server, or encodeURIComponent on the javascript code. And use HttpUtility.UrlDecode to decode it.