Re: Modifying MIME messages with MIME-Tools

[rob_au]

Modifying MIME components with MIME-Tools is not at all impossible - Although I cannot copy and paste code directly from existing code in which I have implemented this functionality using MIME-Tools (as it corporate code), I should be able to provide some example code (see below) to help you in your task.

#   The variable $entity contains a MIME::Entity object returned from 
+MIME::Parser 
#   and from this object, a MIME::Body object is retrieved for content
+ manipulation.

my $body = $entity->body;
my $content = $body->as_string;

#   The content of the MIME component can now be modified as you see f
+it

$content =~ s/foo/bar/g;

#   The updated content must now be written back into the MIME message
+ component - 
#   This is performed through manipulation of the MIME::Body object.

my $io = $body->open('w');
$io->print( $content )
$io->close;

#   At this point, you may need to re-synchronise the headers of the M
+IME::Entity 
#   object - This method will add or update a Content-Length header wi
+thin the 
#   MIME component.

$entity->sync_headers(
        'Length'        =>  'COMPUTE',
        'Nonstandard'  =>  'ERASE'
);

[skazat]

Rob,

Thanks for given me that to go on! I think I've cracked it! I did have to tweak your code to the following to make it work with my setup:

#   The variable $entity contains a MIME::Entity object returned from 
+MIME::Parser 
#   and from this object, a MIME::Body object is retrieved for content
+ manipulation.

my $body = $entity->bodyhandle;
my $content = $body->as_string;

#   The content of the MIME component can now be modified as you see f
+it

$content =~ s/foo/bar/g;

#   The updated content must now be written back into the MIME message
+ component - 
#   This is performed through manipulation of the MIME::Body object.

my $io = $body->open('w');
$io->print( $content )
$io->close;

#   At this point, you may need to re-synchronise the headers of the M
+IME::Entity 
#   object - This method will add or update a Content-Length header wi
+thin the 
#   MIME component.

$entity->sync_headers(
        'Length'        =>  'COMPUTE',
        'Nonstandard'  =>  'ERASE'
);

basically, the line that says,

my $body = $entity->body; Needed to be:

my $body = $entity->bodyhandle;

[skazat]

OK!

Here's my Proof of Concept to edit specific MIME types in a MIME Message. This example will only tweak parts that are in text/plain. How to exactly edit the mime part was graciously given by rob_au, all that had to after that was to create a recursive subroutine that would then reconstruct everything tweaked!

 
#!/usr/bin/perl -w
use strict; 

use MIME::Parser; 
use MIME::Entity; 

my $parser = new MIME::Parser; 
   $parser->output_to_core(1); 

#so here's our test MIME thingy:

my $test = MIME::Entity->build(Type     => "multipart/alternative",
                              From     => '[e-mail]',
                              To       => '[e-mail]',
                              Subject  => "Test Test Test");

$test->attach(Type => "text/plain", 
             Data => "This is the plain text stuff"
             );
             
$test->attach(Type => "text/html", 
             Data => "<h1>This is the HTML stuff</h1>"
             );
             
             
# Let's print the, "Before"
print $test->as_string();
$test = tweak_plain_text($test); 

print "\n\nAnd After...\n\n\n";

print $test->as_string();


sub tweak_plain_text { 

    my $entity = shift; 
    my @parts  = $entity->parts; 
    
    if(@parts){
        my $i; 
        foreach $i (0 .. $#parts) {
            $parts[$i]= tweak_plain_text($parts[$i]);    
        }
        $entity->sync_headers('Length'      =>  'COMPUTE',
                              'Nonstandard' =>  'ERASE');
    }else{ 
        if($entity->head->mime_type eq 'text/plain'){ 
            my $body = $entity->bodyhandle;
            my $content = $body->as_string;
               $content .= "\nThis has been tweaked!!!!\n";
               my $io = $body->open('w');
                  $io->print( $content );
                  $io->close;
            $entity->sync_headers('Length'      =>  'COMPUTE',
                                  'Nonstandard' =>  'ERASE');
        }
        return $entity; 
    }
    
    my $content = $entity->as_string; 
    
    return $entity; 
}

Thanks everyone for the help!