From db4d08d2d36a115ccc885e04e37fcd3d5cbc8097 Mon Sep 17 00:00:00 2001
From: Pekka Helenius <fincer89@hotmail.com>
Date: Sat, 8 Jun 2019 12:30:47 +0300
Subject: [PATCH] Main sh script: Code clean-up & improvements

Clean-up & reorganize code. Basic support for multiple email recipients. Delete redundant code parts.
---
 wanchecker.sh | 91 +++++++++++++++++++++++----------------------------
 1 file changed, 41 insertions(+), 50 deletions(-)

diff --git a/wanchecker.sh b/wanchecker.sh
index b901550..58f6164 100644
--- a/wanchecker.sh
+++ b/wanchecker.sh
@@ -19,7 +19,7 @@
 ###########################################################
 
 # A script for remote server environments which are behind
-# dynamic (non-static) DHCP. Usually these dynamic IPs are 
+# dynamic (non-static) DHCP. Usually these dynamic IPs are
 # used in common household networks in non-corporate
 # environments.
 
@@ -44,95 +44,86 @@
 # Some lines below are commented out because the timer is handled by systemd service file
 # If you don't use provided systemd service file, re-enable the relevant lines below
 
-function checkWANIP() {
+function checkWANIP {
 
   # Command to resolve the current IPv4 WAN address
   local WANIP_CURRENT="dig +short myip.opendns.com @resolver1.opendns.com"
 
+  # Log file timestamp format
+  local TIMESTAMP=$(date '+%d-%m-%Y, %X')
+
+############################
+
+  # Email sender
+  local EMAIL_SENDER="mailsender@foo.com"
+
+  # Emails to send notification to
+  local EMAIL_RECIPIENTS=(
+    "whogetsthemail_1@foo.com"
+    "whogetsthemail_2@bar.com"
+  )
+
+############################
+
+  # Email send function
+  function mailSend {
+    echo -e "To: ${1}\nFrom: ${EMAIL_SENDER}\nSubject: ${SUBJECT_EMAIL}\n\n${MESSAGE_EMAIL}" | sendmail -v "${1}"
+  }
+
 ############################
 
   # If we are connected to internet...
   # There's no point to do WAN IP check if we can't establish connection to WAN/Internet at all
   # In addition, do not generate any network related variables if the connection
   # can't be established. Therefore, include variable defitions inside this if statement.
-  if [[ $(printf $(eval ${WANIP_CURRENT} &> /dev/null)$?) -eq 0 ]]; then
-
-    # Check interval in minutes
-  #  local CHECK_INTERVAL=5
+  if [[ $(printf $(eval "${WANIP_CURRENT}" &> /dev/null)$?) -eq 0 ]]; then
 
 ############################
 
     # Cache/Log directory of the script
     local WANIP_DIR="$HOME"
 
-    # Log file for checked/resolved IPv4 WAN addresses:
+    # Log file for checked/resolved IPv4 WAN addresses
     local WANIP_LOG="$WANIP_DIR/.ip_wan.log"
 
-    if [[ ! -d ${WANIP_DIR} ]]; then
-      mkdir -p ${WANIP_DIR}
+    if [[ ! -d "${WANIP_DIR}" ]]; then
+      mkdir -p "${WANIP_DIR}"
     fi
 
-    if [[ ! -f ${WANIP_LOG} ]]; then
-      printf 'Time\t\t\t\tWAN IPv4\n' > ${WANIP_LOG}
+    if [[ ! -f "${WANIP_LOG}" ]]; then
+      printf 'Time\t\t\t\tWAN IPv4\n' > "${WANIP_LOG}"
     fi
 
-############################
-
-    # Log file timestamp format
-    local TIMESTAMP=$(date '+%d-%m-%Y, %X')
-
-############################
-
-    # Email to send notify to
-    local EMAIL_RECIPIENT="mymail@hotmail.com"
-
     # Email subject/title
-    local SUBJECT_EMAIL="WAN IP address change (Helsinki, $(tail -1 ${WANIP_LOG} | awk '{print $NF}') -> $(eval ${WANIP_CURRENT}))"
+    local SUBJECT_EMAIL="WAN IP address changed (Helsinki, $(tail -1 ${WANIP_LOG} | awk '{print $NF}') -> $(eval ${WANIP_CURRENT}))"
 
     # Email message/body contents
-    local MESSAGE_EMAIL="${TIMESTAMP}: WAN address of the server (Helsinki) has been changed from $(tail -1 ${WANIP_LOG} | awk '{print $NF}') to $(eval ${WANIP_CURRENT})"
+    local MESSAGE_EMAIL="${TIMESTAMP}: WAN address of location (Helsinki) has been changed from $(tail -1 ${WANIP_LOG} | awk '{print $NF}') to $(eval ${WANIP_CURRENT})"
 
     # Message to server stdout
     local MESSAGE_STDOUT="$(echo ${TIMESTAMP}) - WAN address of this server has been changed from $(tail -1 ${WANIP_LOG} | awk '{print $NF}') to $(eval ${WANIP_CURRENT})"
 
 ############################
 
-    # Email send command
-    local MAIL_SEND="echo -e \"To: ${EMAIL_RECIPIENT}\nFrom: ${EMAIL_RECIPIENT}\nSubject: ${SUBJECT_EMAIL}\n\n${MESSAGE_EMAIL}\" | sendmail -v ${EMAIL_RECIPIENT}"
-
     # Log write command
-    local LOG_WRITE="printf '%s %s\t\t%s\n' $(echo $TIMESTAMP) $(eval $WANIP_CURRENT) >> $WANIP_LOG"
+    local LOG_WRITE=$(printf '%s %s\t\t%s\n' $(echo "${TIMESTAMP}") $(eval "${WANIP_CURRENT}") >> "${WANIP_LOG}")
 
 ############################
 
-    # If the log file has no previous IPv4 entries
-    if [[ $(cat $WANIP_LOG | wc -l) -le 1 ]]; then
-      eval ${LOG_WRITE}
-    fi
-
-#  local i=0
-#  while true; do
+    if [[ $(tail -1 "${WANIP_LOG}" | awk '{print $NF}') != $(printf '%s' $(eval "${WANIP_CURRENT}")) ]] || \
+    [[ $(cat "${WANIP_LOG}" | wc -l) -le 2 ]] ; then
 
-#    if [[ $i -ne 0 ]]; then
-#      sleep $(( ${CHECK_INTERVAL} * 60 ))
-#    fi
+      echo -e "${MESSAGE_STDOUT}"
 
-#    if [[ -f $WANIP_LOG ]]; then
+      for i in "${EMAIL_RECIPIENTS[@]}"; do
+        mailSend "${i}"
+        $LOG_WRITE
+      done
 
-      # The log file must include more than just the header line
-    if [[ $(cat $WANIP_LOG | wc -l) -gt 1 ]]; then
-
-      if [[ $(tail -1 $WANIP_LOG | awk '{print $NF}') != $(printf '%s' $(eval $WANIP_CURRENT)) ]]; then
-
-        echo -e ${MESSAGE_STDOUT}
-        eval ${MAIL_SEND}
-        eval ${LOG_WRITE}
-
-      fi
     fi
+
   fi
-#    let i++
-#  done
+
 }
 
 ############################