Teachers inbox sharing mechanism

sharemon.sh

#!/bin/bash -eu
# This monitors the incoming_dir (directories named after their users)
# Any zip files uploaded to said dirs will be shared in the shared_dir
# under a random directory, and the link emailed to the users.
# Requires dma, but you can replace that with other MTAs.

incoming_dir='/home/share'
shared_dir='/var/www/drop'
share_server='share.rhavenindustrys.com/drop'
webkey_size='64'
email_domain='rhavenindustrys.com'
filetypes="
	-iname *.tar -o 
	-iname *.tgz -o
	-iname *.tar.gz -o
	-iname *.gz -o
	-iname *.tbz2 -o 
	-iname *.zip -o
	-iname *.7z -o
	-iname *.iso
	"
webkey=''

function rand_string { 
	charpool=('a' 'b' 'c' 'd' 'e' 'f' 'g' 'h' 'i' 'j' 'k' 'l' 'm' 'n' 'o' 'p' 'q' 'r' 's' 't' 'u' 'v' 'w' 'x' 'y' 'z' \
		   'A' 'B' 'C' 'D' 'E' 'F' 'G' 'H' 'I' 'J' 'K' 'L' 'M' 'N' 'O' 'P' 'Q' 'R' 'S' 'T' 'U' 'V' 'W' 'X' 'Y' 'Z' \
		   '0' '1' '2' '3' '4' '5' '6' '7' '8' '9' '0' '-' )

	charpool_length=${#charpool[*]}
 
	if [ $# -lt 1 ]; then num=${webkey_size}; else num=${1}; fi
 
	for c in $(seq $num); do
        	echo -n ${charpool[$((${RANDOM} % ${charpool_length}))]}
	done
	echo ""
}

function send_mail {

echo "\
To: "${2}@${email_domain}"
Subject: New ShareMon Link Created

Hello,

A new file has been uploaded. You can access this file for 24 hours at the following link:
https://${share_server}/${1}

Please be aware, anyone who has this link will be able to access this file. If the contents are sensitive, please consider encrypting the zip file before you upload it, and sharing the encryption key by a separate method, like phone, fax, or encrypted email. 

Thanks,
The IT Script Gremlin
" | dma -t -f "sharemon@${email_domain}"

}

for user_dir in $(ls -1 ${incoming_dir}); do
	# Check if there are files in the directory
	if [ $(find "${incoming_dir}/${user_dir}" -type f ${filetypes}| wc -l) -gt 0 ]; then
		IFS=$'\n'
		for file in $(IFS=$' \t\n';find "${incoming_dir}/${user_dir}" -type f ${filetypes}); do
			
			# Check if file has not been modified in 60 seconds
			if [ $(($(stat -c %Y "${file}") + 55)) -lt $(date +%s) ]; then
				webkey="$(rand_string)"
				new_file="$(basename "${file}" | sed 's/\ /_/g')"
				mkdir "${shared_dir}/${webkey}"
				chmod a+r "${file}"
				mv "${file}" "${shared_dir}/${webkey}/${new_file}"
				
				send_mail "${webkey}/${new_file}" "${user_dir}"
			fi
		done
	fi
done

# Delete files older than 24 Hours
if [ $(ls -1 ${shared_dir} | wc -l) -gt 0 ]; then
	find ${shared_dir}/ -mindepth 1 -type d -ctime +1 -exec rm -rf {} \;
fi