in reply to mime tools attachments

I'm not that familiar with mime-tools, but I'll take a stab at your problem, and hopefully I can help.

First of all, my testing code, and its output (mostly taken from what you posted).

Code: 

#!/usr/bin/perl -w

use strict;
use MIME::Entity;

my @attach   = ( q{This is to inform you}, 
                 q{that you have won}, 
                 q{a number of tribbles.} );
my @msg_body = ( q{This is to inform you}, 
                 q{that this is},
                 q{a test.} );
my $entity = MIME::Entity->build( Type => 'multipart/mixed', 
                                  From => 'email', 
                                  To => 'address', 
                                  Subject => "blah", )
  or die "Error creating MIME entity: $!\n";

$entity->attach(
    Type => 'text/plain',

    #Encoding => 'base64',
    Data => join( "\n", @msg_body )
);
$entity->attach( Filename => "report.txt", 
                 Type => 'text/plain', 
                 Data => join( "\n", @attach ) )
  or die "Error adding the text message part: $!\n";

# $entity->smtpsend;
$entity->print( \*STDOUT );

[download]

Output: 

Content-Type: multipart/mixed; boundary="----------=_1097554778-11801-
+0"
Content-Transfer-Encoding: binary
MIME-Version: 1.0
X-Mailer: MIME-tools 5.411 (Entity 5.404)
From: email
To: address
Subject: blah

This is a multi-part message in MIME format...

------------=_1097554778-11801-0
Content-Type: text/plain
Content-Disposition: inline
Content-Transfer-Encoding: binary

This is to inform you
that this is
a test.
------------=_1097554778-11801-0
Content-Type: text/plain; name="report.txt"
Content-Disposition: inline; filename="report.txt"
Content-Transfer-Encoding: binary

This is to inform you
that you have won
a number of tribbles.
------------=_1097554778-11801-0--

[download]

I then compared this with the source for an email in which I sent a coworker a perl script, in which the headers for that (which does show up as an attachment) are as follows: 

Content-Disposition: attachment; filename=blah.pl
Content-Type: text/x-perl; name=blah.pl; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

[download]

I suspect strongly that the issue is that in the results of your code, the Content-Disposition is 'inline', rather than 'attachment', suggesting to the mail client to attempt to display it rather than show it as an attachment. So, in the code, I changed the attach line for 'report.txt' to the following, which seems to generate the appropriate entry: 

$entity->attach( Disposition => 'attachment', 
                 Filename => "report.txt", 
                 Type => 'text/plain', 
                 Data => join( "\n", @attach ) )
  or die "Error adding the text message part: $!\n";

[download]

Having done that, the headers for that section became: 

Content-Type: text/plain; name="report.txt"
Content-Disposition: attachment; filename="report.txt"
Content-Transfer-Encoding: binary

[download]

I'm not sure that is quite the preferred way to do it, but it seems as if it might help. You would need to test to verify, however.

I hope that helps.

In Section Seekers of Perl Wisdom