(DIR) <- Back # Setup your own mail paste service Last modification on 2024-02-10 ## How it works * The user sends a mail with an attachment to a certain mail address, for example: paste@somehost.org * The mail daemon configuration has an mail alias to pipe the raw mail to a shellscript. * This shellscript processes the raw mail contents from stdin. ## What it does * Process a mail with the attachments automatically. * The script processes the attachments in the mail and stores them. * It will mail (back) the URL where the file(s) are stored. This script is tested on OpenBSD using OpenBSD smtpd and OpenBSD httpd and the gopher daemon geomyidae. ## Install dependencies On OpenBSD: pkg_add mblaze ## smtpd mail configuration In your mail aliases (for example /etc/mail/aliases) put: paste: |/usr/local/bin/paste-mail This pipes the mail to the script paste-mail for processing, this script is described below. Copy the below contents in /usr/local/bin/paste-mail Script: #!/bin/sh d="/home/www/domains/www.codemadness.org/htdocs/mailpaste" tmpmsg=$(mktemp) tmpmail=$(mktemp) cleanup() { rm -f "$tmpmail" "$tmpmsg" } # store whole mail from stdin temporarily, on exit remove temporary file. trap "cleanup" EXIT cat > "$tmpmail" # mblaze: don't store mail sequence. MAILSEQ=/dev/null export MAILSEQ # get from address (without display name). from=$(maddr -a -h 'From' /dev/stdin < "$tmpmail") # check if allowed or not. case "$from" in "hiltjo@codemadness.org") ;; *) exit 0;; esac # prevent mail loop. if printf '%s' "$from" | grep -q "paste@"; then exit 0 fi echo "Thank you for using the enterprise paste service." > "$tmpmsg" echo "" >> "$tmpmsg" echo "Your file(s) are available at:" >> "$tmpmsg" echo "" >> "$tmpmsg" # process each attachment. mshow -n -q -t /dev/stdin < "$tmpmail" | sed -nE 's@.*name="(.*)".*@\1@p' | while read -r name; do test "$name" = "" && continue # extract attachment. tmpfile=$(mktemp -p "$d" XXXXXXXXXXXX) mshow -n -O /dev/stdin "$name" < "$tmpmail" > "$tmpfile" # use file extension. ext="${name##*/}" case "$ext" in *.tar.*) # special case: support .tar.gz, tar.bz2, etc. ext="tar.${ext##*.}";; *.*) ext="${ext##*.}";; *) ext="";; esac ext="${ext%%*.}" # use file extension if it is set. outputfile="$tmpfile" if test "$ext" != ""; then outputfile="$tmpfile.$ext" fi mv "$tmpfile" "$outputfile" b=$(basename "$outputfile") chmod 666 "$outputfile" url="gopher://codemadness.org/9/mailpaste/$b" echo "$name:" >> "$tmpmsg" echo " Text file: gopher://codemadness.org/0/mailpaste/$b" >> "$tmpmsg" echo " Image file: gopher://codemadness.org/I/mailpaste/$b" >> "$tmpmsg" echo " Binary file: gopher://codemadness.org/9/mailpaste/$b" >> "$tmpmsg" echo "" >> "$tmpmsg" done echo "" >> "$tmpmsg" echo "Sincerely," >> "$tmpmsg" echo "Your friendly paste_bot" >> "$tmpmsg" # mail back the user. mail -r "$from" -s "Your files" "$from" < "$tmpmsg" cleanup The mail daemon processing the mail needs of course to be able to have permissions to write to the specified directory. The user who received the mail needs to be able to read it from a location they can access and have permissions for it also. ## Room for improvements This is just an example script. There is room for many improvements. Feel free to change it in any way you like. ## References (HTM) * https://man.openbsd.org/aliases (HTM) * https://man.openbsd.org/smtpd (HTM) * https://man.openbsd.org/httpd (HTM) * https://github.com/leahneukirchen/mblaze ## Bye bye I hope this enterprise(tm) mail service is inspirational or something ;)