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FTP problem: Get dir listing when expecting 404 Not Found

From: Renate Bahnemann <renate@micromuse.com>
Date: Mon, 11 Aug 2003 12:08:43 +0100
Message-ID: <3F37793B.7D115187@micromuse.com>
To: www-lib@w3.org
Hi

I am new to libwww but have managed to integrate libwww into our
application to retrieve small ASCII files transparently from either an
ftp or webserver.

However, I've hit a snag and would like to propose a small patch that
gets around the problem.

Problem occurs for the following:

ftp://<host>:<port>/<top-dir>/<invalid-dir>/<filename>
	returns an empty directory listing,
	I expected "404 Not Found" error.

By comparison the following scenario's produce:

ftp://<host>:<port>/<top-dir>/<valid-dir>
	returns "404 Not Found"

ftp://<host>:<port>/<top-dir>/<valid-dir>/
	returns directory listing

ftp://<host>:<port>/<top-dir>/<invalid-dir>
	return "404 Not Found"

I am wondering whether the current behaviour of the library conforms to
paragraph 3.2.2 of RFC 1738.

Here is a portion of the trace of the communication between the client
and the server:
IN is the client
OUT is the server
   ....	
   OUT 230 Guest login ok, access restrictions apply.
   IN  TYPE I
   OUT 200 Type set to I.
   IN  PORT 192,168,35,47,153,217
   OUT 200 PORT command successful.
   IN  RETR /pub/nonsuch/anyfile
   OUT 550 /pub/nonsuch/anyfile: No such file or directory.
   IN  CWD /
   OUT 250 CWD command successful.
   IN  CWD pub
   OUT 250 CWD command successful.
   IN  CWD nonsuch
   OUT 550 nonsuch: No such file or directory.
   IN  SYST
   OUT 215 UNIX Type: L8 Version: SUNOS
   IN  LIST anyfile
   OUT 150 Binary data connection for /bin/ls (192.168.35.47,39385) (0
bytes).
   OUT 226 Binary Transfer complete.

Stepping through the code I found the code that causes this to be in
HTFTP.c(v1.109):
   1568: 	    else if (!FTP_DIR(data) && !data->stream_error) {
   1569: 		FTPListType(data, ctrl->server);

If I delete the above lines, I get the results that I expect and am
wondering whether the changes that were applied to CVS versions 1.95 and
1.104 have not made this code redundant.

I am attaching a patch that shows my changes.
Patch tests OK with: 
	patch HTFTP.c HTFTP.patch

(My platform is Solaris 5.7.
Also the application defaults to FTP_DEFAULT_TRANSFER_MODE (i.e. 'I'))

Is my 'fix' valid or am I misunderstanding something and making a
mistake in my application?

Regards
Renate
*** HTFTP.c.orig	Fri Aug  8 19:35:58 2003
--- HTFTP.c	Fri Aug  8 19:29:57 2003
***************
*** 1563,1575 ****
  		ctrl->state = FTP_SUCCESS;
  	    else if (status == HT_OK)
  		ctrl->state = FTP_NEED_DCON;
! 	    else if (HTRequest_method(request) == METHOD_PUT)
  		ctrl->state = FTP_ERROR;
- 	    else if (!FTP_DIR(data) && !data->stream_error) {
- 		FTPListType(data, ctrl->server);
- 		ctrl->state = FTP_NEED_SERVER;         /* Try a dir instead? */
- 	    } else
- 		ctrl->state = FTP_ERROR;
  	    break;
  
  	  case FTP_NEED_SERVER:
--- 1563,1570 ----
  		ctrl->state = FTP_SUCCESS;
  	    else if (status == HT_OK)
  		ctrl->state = FTP_NEED_DCON;
! 	    else
  		ctrl->state = FTP_ERROR;
  	    break;
  
  	  case FTP_NEED_SERVER:
Received on Monday, 11 August 2003 07:10:21 GMT

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