#!/bin/bash
#
# WordPress Update Notify 0.1, January 2010
# by Philipp Heckel; No license, feel free use it!
#
# WP-UN checks whether a local WordPress installation is 
# up-to-date and notifies the administrator if a new version
# is available.
#
# Original blog post:
#   http://blog.philippheckel.com/2010/01/29/wp-un-wordpress-version-update-notification-with-cron/
#
# REQUIREMENTS
#   Local mail server, e.g. postfix, sendmail, ...
#
# USAGE
#   $ ./wp-un [--test] <INSTALL-DIR> <NOTIFY-EMAIL>
#
# AS CRONJOB
#   0 6 * * * /usr/local/bin/wp-un /var/www/myblog admin@example.com 
#

### Parse Parameters ####################################
PATH="/bin:/sbin:/usr/bin:/usr/sbin"

if [ $# -le 1 ]; then
        echo "Usage: $0 [--test] <INSTALL-DIR> <NOTIFY-EMAIL>"
	echo "  e.g. $0 /var/www/wordpress mymail@example.com"
        exit 1
fi

if [ "$1" == "--test" ]; then
	TEST=1
	WORDPRESS="$2"
	NOTIFY_EMAIL="$3"
else
	WORDPRESS="$1"
	NOTIFY_EMAIL="$2"
fi

URL="http://www.wordpress.org/latest.tar.gz"
VERSION_FILE="$WORDPRESS/wp-includes/version.php"

if [ ! -f "$VERSION_FILE" ]; then
	echo "ERROR: No WordPress installation found at $WORDPRESS"
	exit 2
fi

if [ ! -x "$(which sendmail)" ]; then 
	echo "ERROR: No sendmail compatible mail server found."
	exit 3
fi

### Script Start ###########################################

## Determine installed version
if [ -n "$TEST" ]; then echo -n "Checking installed version... "; fi

INSTALLED=$(cat "$VERSION_FILE" \
	| grep '\$wp_version[ ]*=' \
	| sed -r "s/.+'(.+)';/\1/")

if [ -n "$TEST" ]; then echo "WordPress $INSTALLED"; fi


## Determine latest version
if [ -n "$TEST" ]; then echo -n "Checking latest version... "; fi

# Alternative to 'wget': curl -I "$URL" 2> /dev/null
LATEST=$(wget -S --spider "$URL" 2>&1 \
	| grep -o -E 'Content-Disposition.+.tar.gz' \
	| sed -r 's/.+filename=wordpress-(.+)\.tar\.gz/\1/')

if [ -n "$TEST" ]; then echo "WordPress $LATEST"; fi


## Notify if versions differ
if [ -n "$TEST" -o "$INSTALLED" != "$LATEST" ]; then
	if [ -n "$TEST" ]; then
		if [ "$INSTALLED" != "$LATEST" ]; then
			echo -n "Update required; Sending notification to $NOTIFY_EMAIL... "
		else
			echo "Update not necessary; WordPress is up-to-date."
			echo -n "TEST-flag enabled: sending notfication to $NOTIFY_EMAIL... "
		fi
	fi

	# Send to e-mail address
	HOSTNAME="$(hostname)"

	# Alternative to 'sendmail': mailx -s "..." $NOTIFY_EMAIL
	echo -e "To: $NOTIFY_EMAIL\nSubject: Notification: WordPress $LATEST available\n\n" \
		"The WordPress installation on host $HOSTNAME needs an update:\n\n" \
		"  Installed Version: WordPress $INSTALLED\n" \
		"                 at: $WORDPRESS\n\n" \
		"     Latest Version: WordPress $LATEST\n" \
		"           Download: $URL" \
		| sendmail -t "$NOTIFY_EMAIL"

	if [ -n "$TEST" ]; then echo "done."; fi
fi