Re: [MacPerl] Select body of a mailbox

[Ken Williams <ken@forum.swarthmore.edu>]

g.valoti@magneticmedia.com (Giorgio Valoti) wrote:
>
>Yep it works... here's tjust a test script:
>
>#! /usr/bin/perl -w
>
>use strict;
>use Mail::Util;
>use Mail::Header;
>
>my $mailbox = "path:to:mailbox";
>open MAILBOX, $mailbox
> or die "Non posso aprire MAILBOX: $!\n";
>open HEADER, ">Macintosh HD:Desktop Folder:Header"
> or die "Non posso aprire HEADER: $!";
>open BODY, ">Macintosh HD:Desktop Folder:Body"
> or die "Non posso aprire BODY: $!";
>my $fh = \*MAILBOX;
>my @msgs = Mail::Util::read_mbox($mailbox);
>
>
>
>foreach my $msg (@msgs)
>{
> my $head = new Mail::Header $msg;
> my $header = $head -> header ($msg);
> print HEADER @$header;
> print BODY @$msg;
>}
>
>close MAILBOX;
>close HEADER;
>close BODY;
>
>Now, with the test file (>13MB) I had to increase the Perl memory partition
>to  45MB.... Am I missing something obvious or that's the only way to deal
>with this problem?

It looks like the only way to deal with it using Mail::Util, but that's
because it has to read the whole file into memory.  Here's some code I
wrote several whiles ago (but not tested a whole lot) that doesn't do
that, it simply notes the byte-location of messages and grabs some
important headers.  You could modify it to get whatever portions you're
interested in.


   sub get_mailbox_list {
     # This routine scans the mbox file and fills up the @messages array.
     seek FILE, 0, 0;
     my @messages = ();

     # The goals here: don't read huge portions of the file into memory at
     # once. We go line-by-line in the body of the message, but read the
     # headers in one big slurp.  The assumption is that the headers are never
     # unreasonably long, which is pretty much true.  The body might contain
     # large attachments, though, so we have to read it line-by-line unless we
     # want the wrath of the memory manager.
     
     my $i = 0;
     while (<FILE>) {
       if (/^From /) {
         local $/ = ''; # Paragraph mode - gobble up the headers
         $_ = <FILE>;
         while (/^(From|Received|Subject|Date): (.*?)\n(?!\t)/smg) {
           $messages[$i]{$1} = $2 unless exists $messages[$i]{$1};
           # If we cared, we could also replace \n\t with a space
         }
         $messages[$i]{'location'} = tell(FILE) - length();
         $i++;
       }
     }
     return @messages;
   }




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