On 4/6/07, Vincent Massol <vincent@massol.net> wrote:

Hi,

I admit it: I'm not an expert in I8N. However I realize that XWiki
being a wiki we need to have strong I8N features so I'm trying to
catch up with I8N knowledge...

I started yesterday by reading this excellent short tutorial http://
www.joelonsoftware.com/articles/Unicode.html (The Absolute Minimum
Every Software Developer Absolutely, Positively Must Know About
Unicode and Character Sets (No Excuses!)). It's very good and an easy
read. I recommend it to everyone.

It's a bit too short, just when things get interesting, it ends.

This led me to a few questions:

1) Is UTF8 supported on all platforms? Is it supported on mobile
platforms for example?

Platforms old enough not to know UTF are unlikely to support running XWiki on it.

2) I see in our encoding guide on http://www.xwiki.org/xwiki/bin/view/
AdminGuide/Encoding that we need to set the encoding for the
container. Why is that required? The servlet container reads pages
which have the encoding specified (using Content-Type meta data), so
why does it need to be told about the encoding to use?

If you mean the parameter in web.xml, then it's not the container encoding, but a parameter used to correctly identify outgoing files (it sets the Content-Type header according to this param).

There are more files which don't have a Content-Type. First there are the files stored on disk. Second, when you POST some data or GET a resource, you don't have a content type. Requests don't have this HTTP header.

3) I see that in our standalone installation we use -
Dfile.encoding=iso-8859-1 . Now that I've read Joel's tutorial it
seems to me this is not going to work for everyone and that we should
rather use -Dfile.encoding=UTF-8 by default. WDYT?

UTF-8 is better. But we really should not depend on the file encoding.

4) Should we use the platform encoding or default to using UTF-8 all
the time? (this question is related to 1)). I think we should use the
platform encoding but I'm curious to know what others think.

UTF-8 all the time. Thus we have no dependency on the system, and we don't need guides on "how to change the encoding in only 7 places to make my wiki know bulgarian"

5) Jackson Wang is proposing in a patch to modify readPackage like this:

      private Document readPackage(InputStream is) throws
IOException, DocumentException
      {
-        byte[] data = new byte[4096];
+        //UTF-8 characters could cause encoding as continued bytes
over 4096 boundary,
+        // so change byte to char.  ---Jackson
+        char[] data = new char[4096];
+        BufferedReader in= new BufferedReader(new InputStreamReader
(is));
          StringBuffer XmlFile = new StringBuffer();
          int Cnt;
-        while ((Cnt = is.read(data, 0, 4096)) != -1) {
+        while ((Cnt = in.read(data, 0, 4096)) != -1) {
              XmlFile.append(new String(data, 0, Cnt));
-        }
+       }
          return fromXml(XmlFile.toString());
      }

However with my new understanding I'm not sure this would help as
char are stored on 2 bytes in Java and UTF-8 encoding can store on up
to 4 bytes. Am I correct?

However, I would rather use http://jakarta.apache.org/commons/io/api-
release/org/apache/commons/io/IOUtils.html#toString
(java.io.InputStream) than code it ourselves... Sounds safer,
shorter, less maintenance, etc to me... :)

+1. Always reuse existing proven code than reinvent a squeaky wheel.

Thanks for your help
-Vincent