Bug#946956: mime-base64to8bit mime base64 text -> raw text tool

[Ian Jackson]

Package: mailscripts
Severity: wishlist

I needed a utility for base64-decoding text parts of MIME messages.

All the tools I tried would (i) fail to crlf->lf convert the text part
(as is needed) or (ii) have an interface which was just too
inconvenient.  Or both.

I'm afraid I have not supplied a manpage, help message, etc.

This program is useful with formail to work around a bug in git-am,
where if it gets a base64-encoded patch it fails because the base64
correctly contains cr-lf line endings.

Ian.


#!/usr/bin/perl -w

# Copyright (C)2019 Citrix plc
# Author: Ian Jackson <ian.jack...@eu.citrix.com>
# GPLv3+

use strict;
use MIME::Parser;

die if @ARGV;

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

my $e=$p->parse(\*STDIN);

sub decode_entity ($);
sub decode_entity ($) {
    my ($e) = @_;
    my $t = $e->effective_type();
    if ($t =~ m{^text/}) {
        my $b = $e->bodyhandle();
        if ($b) {
            my @l = $b->as_lines();
            s/\r$// foreach @l;
            my $b2 = new MIME::Body::InCore \@l;
            $e->bodyhandle($b2);
            $e->head->replace("Content-Transfer-Encoding","8bit");
        }
    }
    foreach my $part ($e->parts()) {
        decode_entity($part);
    }
}

decode_entity($e);

$e->print(\*STDOUT);