Hello,
I found another problem with using the local Platform
default encoding for ChannelSftp:
* Take a local Windows box with default encoding ("Cp1252")
and a remote Linux (RHEL4) box with UTF-8 encoding.
* There are some Unicode characters that lead to bytes
which cannot be expressed in Cp1252: For instance, the
character 'č' includes 0x8d in UTF-8 and byte 0x8d
is not defined in Cp1252.
* As a result, when reading the directory with the standard
encoding, Jsch replaces character 'č' by a question mark
'?'
* But even glob_remote cannot resolve the question mark by
the original bytes --> as a result, remote files which
include the 'č' character cannot be worked on at all!
--> no stat(), no ls() etc... no Jsch ChannelSftp command
at all works on such files.
I thus find this issue REALLY problematic, and I'd vote for
- provide a ChannelSftp.setControlEncoding()
- have the default encoding be UTF-8
Cheers,
--
Martin Oberhuber
Wind River Systems, Inc.
Target Management Project Lead, DSDP PMC Member
http://www.eclipse.org/dsdp/tm
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf
> Of Oberhuber, Martin
> Sent: Friday, September 21, 2007 11:48 AM
> To: Atsuhiko Yamanaka
> Cc: jsch-users@lists.sourceforge.net
> Subject: Re: [JSch-users] Jsch ChannelSftp and character encodings
>
> Hello Atsuhiko,
>
> I'm not a big expert on encodings, but it seems to me
> that unconditionally focing UTF-8 is not the right
> thing to do, at least for the following reasons:
>
> 1.) As I understand it, on a UNIX box every user is free
> to choose his own encoding. User A could be using UTF-8
> but user B could be using ISO8859-1 or whatever he prefers.
> In the shell, the change is made by setting an environment
> variable.
> But how would the SSHD know what encoding a user prefers?
> It's running as root, isn't it? So how would it convert
> from UTF-8 to the user's preferred encoding?
>
> 2.) Although RFC seems to recomment UTF-8, it looks like
> practical implementation does not use it to recode.
>
> 3.) Old version of Jsch defaulted to something else, so if
> files with extended chars were written with old Jsch
> they cannot be read properly with new Jsch when you
> force UTF-8.
>
> because of all these reasons, I still think the better way
> is to allow client choose the default encoding, as I was
> proposing. If it turns out that UTF-8 is the correct default,
> client can
> Channel.setDefaultEncoding("UTF-8");
> otherwise, other client's favorite encoding can be set.
>
> But as I said, I'm not the big expert on encodings and I'm
> happy to discuss this.
>
> Cheers,
> --
> Martin Oberhuber
> Wind River Systems, Inc.
> Target Management Project Lead, DSDP PMC Member
> http://www.eclipse.org/dsdp/tm
>
> > -----Original Message-----
> > From: Atsuhiko Yamanaka [mailto:[EMAIL PROTECTED]
> > Sent: Thursday, September 20, 2007 4:58 AM
> > To: Oberhuber, Martin
> > Cc: jsch-users@lists.sourceforge.net
> > Subject: Re: [JSch-users] Jsch ChannelSftp and character encodings
> >
> > Hi,
> >
> > +-From: "Oberhuber, Martin" <[EMAIL PROTECTED]> --
> > |_Date: Wed, 19 Sep 2007 11:47:37 +0200 _______________________
> > |
> > |I'm wondering if anybody thought about the case yet where
> > |I'd like to transfer files via Sftp, where the file names
> > |Use non-ASCII foreign language characters, and the character
> > |Encoding on the local system is different than the remote.
> > |
> > |Say, I want to transfer from a Windows box to a Linux box.
> > |On Windows, my encoding is Cp1252
> > |On remote Linux, my encoding is UTF-8
> > |I want to transfer file "m,Mv(Bchte"
> > |
> > |Currently, channel always seems to encode Java Unicode Strings
> > |With Platform default encoding (Cp1252 in my case). On the
> > |Remote, file names will not appear as expected.
> >
> > Yes, it is a bug/incompleteness of jsch.
> >
> > As far as I have understood, we have to send filenames in UTF-8 over
> > sftp protocol. For example, its IETF draft[1] has said as follows,
> >
> > 8.1.1. Opening a File
> > Files are opened and created using the SSH_FXP_OPEN message.
> > byte SSH_FXP_OPEN
> > uint32 request-id
> > string filename [UTF-8]
> > uint32 desired-access
> > uint32 flags
> > ATTRS attrs
> >
> > On the other hand, in the current jsch implementation,
> > filenames have been sent in the local default encoding.
> >
> > I'll fix it in the next version, but it will cause the
> > troubles for others.
> > It seems to me that OpenSSH(for example, openssh-4.7p1)'s
> > sftp-server has
> > not implemented such encoding conversion. So, as for the
> avobe case,
> > if the remote host does not use UTF-8, users will get
> > unexpected results.
> > This is the reason I had not implemented it.
> >
> > |To fix this, I think there should be
> > | Channel.setControlEncoding(String encoding)
> > |So I can specify the encoding to use forr file and
> > |Path names on the remote. At the time the Java unicode
> > |String for arguments is converted to byte arrray, it
> > |Should do so with the default encoding specified by me.
> >
> > Unfortunately, the client does not have the initiative to choose the
> > encoding and filenames must be sent in UTF-8 according to the RFC.
> >
> >
> > [1] http://tools.ietf.org/html/draft-ietf-secsh-filexfer-13
> >
> >
> > Sincerely,
> > --
> > Atsuhiko Yamanaka
> > JCraft,Inc.
> > 1-14-20 HONCHO AOBA-KU,
> > SENDAI, MIYAGI 980-0014 Japan.
> > Tel +81-22-723-2150
> > +1-415-578-3454
> > Fax +81-22-224-8773
> > Skype callto://jcraft/
> >
>
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