From 5ac27ba832ad9d68df498e65dd51a1cf8f6db1b5 Mon Sep 17 00:00:00 2001
From: Akira Matsuda <ronnie@dio.jp>
Date: Fri, 24 Oct 2025 04:04:08 +0900
Subject: [PATCH 1/3] Decode encoded attachments

---
 app/models/message.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/models/message.rb b/app/models/message.rb
index f873c96..e08aa58 100644
--- a/app/models/message.rb
+++ b/app/models/message.rb
@@ -67,7 +67,7 @@ def from_mail(mail, list, list_seq)
         handle_body p
       end
     elsif part.attachment?
-      file = StringIO.new(part.body.raw_source)
+      file = StringIO.new(part.decoded)
       attachments.attach(io: file, filename: part.filename, content_type: part.content_type)
     else
       case part.content_type&.downcase

From 3ce00fdeb5e2f2522933fa9c80c43204af49f42f Mon Sep 17 00:00:00 2001
From: Akira Matsuda <ronnie@dio.jp>
Date: Fri, 24 Oct 2025 04:16:50 +0900
Subject: [PATCH 2/3] x-gzip64 decoder for Mail gem

---
 lib/mail/encodings/x_gzip64.rb | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 lib/mail/encodings/x_gzip64.rb

diff --git a/lib/mail/encodings/x_gzip64.rb b/lib/mail/encodings/x_gzip64.rb
new file mode 100644
index 0000000..661a787
--- /dev/null
+++ b/lib/mail/encodings/x_gzip64.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require 'mail/encodings/base64'
+require 'zlib'
+
+module Mail
+  module Encodings
+    class XGzip64 < Base64
+      NAME = 'x-gzip64'
+      PRIORITY = 3
+      Encodings.register(NAME, self)
+
+      def self.decode(str)
+        base64str = Utilities.decode_base64(str)
+        ActiveSupport::Gzip.decompress(base64str)
+      end
+    end
+  end
+end

From fc506009515f03300cf82d4a11e122594b62d845 Mon Sep 17 00:00:00 2001
From: Akira Matsuda <ronnie@dio.jp>
Date: Fri, 24 Oct 2025 04:17:26 +0900
Subject: [PATCH 3/3] Load x-gzip64 decoder before processing emails

---
 bin/import_mails | 1 +
 1 file changed, 1 insertion(+)

diff --git a/bin/import_mails b/bin/import_mails
index 1678060..60fb8cd 100755
--- a/bin/import_mails
+++ b/bin/import_mails
@@ -2,6 +2,7 @@
 
 require 'optparse'
 require 'mail'
+require 'mail/encodings/x_gzip64'
 
 BASE_DIR = Rails.root.join('tmp')