crop-swap-mail-list/cropswap-sendmail.sh

#!/bin/bash
set -euo pipefail
WD=$(mktemp -d)
cleanup (){
	rm -rf "${WD}"
}
trap cleanup EXIT

cd "${WD}"

ITER_SUBS=/opt/cropswap/gdbm-iter-subscriptions.py
MIME_INJECT=/opt/cropswap/mime-inject.py
DELIVERED=false
SENDMAIL="/usr/sbin/sendmail"
if ((DEBUG != 0)); then
	SENDMAIL="$DEBUGMAIL"
fi

mk_subject(){
	subject="$(cat subject)"
	if [ "${subject/\[${SUBJECT}\]/}" == "${subject}" ]; then
		subject="[${SUBJECT}] ${subject## }"
	fi
	echo "${subject}"
}

tee >(reformail -c -x "Subject:" >subject) original | "${MIME_INJECT}" "${MAILGROUP}" | reformime -s1 -e > body
reformail \
	-X "Date:" \
	-X "MIME-Version:" \
	-X "Subject:" \
	-X "Content-Type:" \
< original | reformail \
	-U "MIME-Version:" \
	-U "Content-Type:" | reformail \
	-I "Subject: $(mk_subject)" \
	-I "List-Id: $MAILGROUP" \
	-I "List-Unsubscribe: <mailto:$MAILGROUP?subject=[UNSUBSCRIBE]>" \
	-I "List-Subscribe: <mailto:$MAILGROUP?subject=[SUBSCRIBE]>" \
	-I "List-Post: <mailto:$MAILGROUP>" \
	-I "List-Unsubscribe-Post: List-Unsubscribe=One-Click" \
| cat - body > mail

declare -A SUBSCRIBED
declare -a actions
update(){
	alias="${actions[$1-1]}"
	email="${2}"
	SUBSCRIBED["$email"]="$alias"
}
mapfile -t -c 2 -C update actions <<EOF
$("${ITER_SUBS}" "${MLIST}" "${SLIST}")
EOF

for email in "${!SUBSCRIBED[@]}"; do
	if [ "${email,,}" == "${NOFORWARD,,}" ]; then
		continue
	fi
	if [ "$TO" != "" ] && [ "$email" != "$TO" ]; then
		continue
	fi
	echo "Forwarding mail: "
	echo "From: ${FROM} <${MAILGROUP}>"
	echo "To: ${SUBSCRIBED["$email"]} <${email}>"
	"$SENDMAIL" -F "${FROM}" -f "${MAILGROUP}" "${SUBSCRIBED["$email"]} <${email}>" < mail
	DELIVERED=true
done
if ! $DELIVERED; then
	"$DEBUGMAIL" undelivered
	exit "$UNHANDLED"
fi