[ecf-dev] File name of retrieved file

[Thomas Hallgren <thomas@xxxxxxx>]

When obtaining a file from a remote source it is often good to know the 
intended filename. It might be used in progress reporting and sometimes 
also as a source of information when naming the resulting local file.

The URL in itself is sometimes very cryptic and the path might contain a 
name in some numeric form (calculated UUID perhaps). In some cases, the 
path doesn't contain a name at all (ends with download.php for instance) 
and the actual path is hidden in one of the parameters. When using HTTP, 
the returned "Content-Disposition" response header field is often a much 
better source for the filename the the actual URL.

Using ECF, I cannot obtain this header field and that's OK. There's a 
lot of transfer implementations where use of response headers isn't 
applicable. I would however like a 
IIncomingFileTransfer.getRemoteFileName() method. The HTTP transfer 
could use the Content-Disposition and other file transfer implementation 
could do a best effort based on whatever algorithm that would be 
appropriate for them. I'm attaching the code that Buckminster uses to 
extract the file name from the Content-Disposition header below.

What do you think? Could something like this be make available in ECF 
incoming file transfer?

Regards,
Thomas Hallgren



   /**
    * This regular expression is a simple Content-Disposition header 
parser.
    * Content-Disposition grammar is quite complex, this is really 
simplified.
    * It should be refactored in future versions using proper grammar.
    */
   private final static Pattern s_contentDispositionPattern = 
Pattern.compile(
           
".*;\\s*filename\\s*=\\s*(\"(?:[^\"\\\\]|\\\\.)*\"|[^;\"\\s]+)\\s*(?:;|$)");

   private static String parseContentDisposition(String contentDisposition)
   {
       //Context-Dispositon syntax: 
attachment|inline[;filename="<filename>"]
       //Try to extract the filename form it (and strip quotes if 
they're there)
      
       if (contentDisposition == null)
           return null;
      
       String filename = null;
       Matcher m = s_contentDispositionPattern.matcher(contentDisposition);

       if (m.matches()) {
           filename = m.group(1);
           if (filename.startsWith("\"") && filename.endsWith("\"")) {
               filename = filename.substring(1, 
filename.length()-1).replaceAll("\\\\(.)", "$1");
           }
       }      
       return filename;
   }