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From "Stefan Bodewig (JIRA)" <j...@apache.org>
Subject [jira] Commented: (SANDBOX-176) Enable creation of tool-readable ZIP archives with file names containing non-ASCII characters
Date Tue, 10 Feb 2009 16:47:00 GMT

    [ https://issues.apache.org/jira/browse/SANDBOX-176?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12672314#action_12672314
] 

Stefan Bodewig commented on SANDBOX-176:
----------------------------------------

Hi Wolfgang,

I'm sorry but I cannot seem to find the Mail to me that you are talking about.

There is a sibling bugzilla report for Ant https://issues.apache.org/bugzilla/show_bug.cgi?id=45429
- commons-compress great-grand-parent, so I was aware of the new flag, but I never performed
any comprehensive tests.  Many thanks!

If my reading of appnote is correct, setting the EFS bit implies setting the "version needed
to extract" flag to 3, which may make some archivers refuse to extract the archive.  That's
why I'd prefer more explicit control over the flag than setting it automatically.

In Ant we have users use wide ranges of encodings with the zip task and it seems to work for
other encodings than UTF-8 or CP437 as well, so I'd rather keep that.

WRT ZipInputStream I#d recommend using ZipFile instead which is known to work - implementing
ZIP on top of a non.seekable stream is pretty painful.

I'll look into your patch and see how we can improve the current code while keeping the flexibility
we have right now.

> Enable creation of tool-readable ZIP archives with file names containing non-ASCII characters
> ---------------------------------------------------------------------------------------------
>
>                 Key: SANDBOX-176
>                 URL: https://issues.apache.org/jira/browse/SANDBOX-176
>             Project: Commons Sandbox
>          Issue Type: Improvement
>          Components: Compress
>         Environment: Any / All
>            Reporter: Christian Gosch
>            Assignee: Stefan Bodewig
>         Attachments: commons-compress-utf8-creation-svn741897.patch, utf8-7zip-test.zip,
utf8-winzip-test.zip
>
>
> Currently it is not possible to generate externally readable ZIP archives with java.util.zip.*
or org.apache.commons.compress.* when entries to include shall have names with characters
outside US-ASCII. This should be changed to enable at least org.apache.commons.compress.*
to produce ZIP archives in international context which are readable by usual ZIP archiver
tools like pkzip, gzip, WinZIP, PowerArchiver, WinRAR / rar, StuffIt...
> For java.util.zip.* this is due to a really old flaw on handling entry names: They are
just always rendered as UTF-8, which is kind of Java specific, and not as Cp437, which is
expected and written by most ZIP archiver tools (or eventually all). For more details see:
> http://bugs.sun.com/bugdatabase/view_bug.do;:YfiG?bug_id=4244499
> http://bugs.sun.com/bugdatabase/view_bug.do;:YfiG?bug_id=4820807
> For org.apache.commons.compress.archivers.zip.* the "compress & save" operation can
be easily improved by extending ZipArchive:
> // Add member:
>     protected String m_encoding = null;
> // Add constructor:
>     public ZipArchive(String encoding) {
>         m_encoding = encoding;
>     }
> // Extend doSave(FileOutputStream):
> // ...
> 		// Pack-Operation
> 		ZipOutputStream out = null;
> 		try {
> 			out = new ZipOutputStream(new BufferedOutputStream(output));
>             if (m_encoding != null) {   // added
>                 out.setEncoding(m_encoding);   // added
>             }  // added
> 			while(iterator.hasNext()) {
> // ...
> Now it is possible to instantiate a ZipArchive with "Cp437" as encoding, and external
tools can figure out the original entry names even if they contain non-ASCII characters. (On
the other hand, Java cannot read back & deflate such an archive since it expects UTF-8!)
> The "read & deflate" operation for ZipArchive is more difficult to extend since it
currently relies completely on java.util.zip.* . The other reason is, that ZIP archives do
not contain any hint on the character encoding used for file names etc. It seems that the
usual tools simply use Cp437 and Java simply uses UTF-8 -- without any declaration of reasons.
Thus a deflater has to try.
> For TarArchive the problem is unclear. Here the commons-compress implementation does
not rely on third-party code as far as I can see, and TAR is no Java-bound file type (like
JAR, which is Java-bound). Thus chances are, that everything works well, even when entry names
with non-ASCII characters come into play.

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