Here's a new version of the patch addressing Sean's comments.
>From f4d9e714b556a144644cb597a783e4469506ddd1 Mon Sep 17 00:00:00 2001
From: Jameson Graef Rollins <jroll...@finestructure.net>
Date: Tue, 12 Apr 2022 13:03:53 -0700
Subject: [PATCH] new script to reinject message via sendmail
---
sendmail-reinject | 73 +++++++++++++++++++++++++++++++++++++++++
sendmail-reinject.1.pod | 45 +++++++++++++++++++++++++
2 files changed, 118 insertions(+)
create mode 100755 sendmail-reinject
create mode 100644 sendmail-reinject.1.pod
diff --git a/sendmail-reinject b/sendmail-reinject
new file mode 100755
index 0000000..e50c484
--- /dev/null
+++ b/sendmail-reinject
@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright 2022 Jameson Graef Rollins
+
+import sys
+import argparse
+import subprocess
+
+import email
+from email.policy import default
+from email.utils import parseaddr, getaddresses
+
+
+def sendmail(recipients, message, sender):
+ """send message via sendmail"""
+ cmd = [
+ 'sendmail',
+ '-f', sender,
+ ] + recipients
+ print(' '.join(cmd), file=sys.stderr)
+ subprocess.run(
+ cmd,
+ input=message.as_bytes(),
+ check=True,
+ )
+
+
+def main():
+ parser = argparse.ArgumentParser(
+ description="Reinject an email message via sendmail.",
+ )
+ pgroup = parser.add_mutually_exclusive_group(required=True)
+ pgroup.add_argument(
+ 'message', nargs='?', type=argparse.FileType('rb'),
+ help="email message path or '-' for stdin",
+ )
+ pgroup.add_argument(
+ '-i', '--notmuch-id',
+ help="message ID for notmuch extraction",
+ )
+
+ args = parser.parse_args()
+
+ if args.id:
+ import notmuch2 as notmuch
+ db = notmuch.Database()
+ query = f'id:{args.id}'
+ assert db.count_messages(query) == 1, "Message ID does not match exactly one message??"
+ for msg in db.messages(query):
+ path = msg.path
+ break
+ f = open(path, 'rb')
+ else:
+ f = args.message
+
+ # parse the email message
+ msg = email.message_from_binary_file(f, policy=default)
+
+ sender = parseaddr(msg['from'])[1]
+
+ # extract all recipients
+ tos = msg.get_all('to', [])
+ ccs = msg.get_all('cc', [])
+ resent_tos = msg.get_all('resent-to', [])
+ resent_ccs = msg.get_all('resent-cc', [])
+ recipients = [r[1] for r in getaddresses(tos + ccs + resent_tos + resent_ccs)]
+
+ sendmail(recipients, msg, sender)
+
+
+if __name__ == '__main__':
+ main()
diff --git a/sendmail-reinject.1.pod b/sendmail-reinject.1.pod
new file mode 100644
index 0000000..f89d0f1
--- /dev/null
+++ b/sendmail-reinject.1.pod
@@ -0,0 +1,45 @@
+=encoding utf8
+
+=head1 NAME
+
+sendmail-reinject - reinject an e-mail via sendmail
+
+=head1 SYNOPSIS
+
+B<sendmail-reinject> B<message.eml>
+
+B<sendmail-reinject> B<-> <B<message.eml>
+
+B<sendmail-reinject> B<-i> B<messageID>
+
+
+=head1 DESCRIPTION
+
+B<sendmail-reinject> reinjects a message to your MTA via sendmail.
+The message is read in (via path, stdin, or from notmuch via message
+ID), the sender and recipients are extracted, and the appropriate
+senmdail command is contructed to resent the message.
+
+=head1 OPTIONS
+
+=over 4
+
+=item B<--notmuch-id>,B<-i> B<messageID>
+
+Message ID of message to reinject as know to a local notmuch database.
+Assumes the python3-notmuch package is available.
+
+=item B<--help>, B<-h>
+
+Show usage instructions.
+
+=back
+
+=head1 SEE ALSO
+
+sendmail(1), notmuch(1)
+
+=head1 AUTHOR
+
+B<sendmail-reinject> and this manpage were written by Jameson Graef
+Rollins <jroll...@finestructure.net>.
--
2.35.1
