pi-hole/advanced/Scripts/updatecheck.sh

#!/usr/bin/env bash
# Pi-hole: A black hole for Internet advertisements
# (c) 2017 Pi-hole, LLC (https://pi-hole.net)
# Network-wide ad blocking via your own hardware.
#
# Checks for local or remote versions and branches
#
# This file is copyright under the latest version of the EUPL.
# Please see LICENSE file for your rights under this license.

# Credit: https://stackoverflow.com/a/46324904
function json_extract() {
  local key=$1
  local json=$2

  local string_regex='"([^"\]|\\.)*"'
  local number_regex='-?(0|[1-9][0-9]*)(\.[0-9]+)?([eE][+-]?[0-9]+)?'
  local value_regex="${string_regex}|${number_regex}|true|false|null"
  local pair_regex="\"${key}\"[[:space:]]*:[[:space:]]*(${value_regex})"

  if [[ ${json} =~ ${pair_regex} ]]; then
    echo $(sed 's/^"\|"$//g' <<< "${BASH_REMATCH[1]}")
  else
    return 1
  fi
}

function get_local_branch() {
  # Return active branch
  cd "${1}" 2> /dev/null || return 1
  git rev-parse --abbrev-ref HEAD || return 1
}

function get_local_version() {
# Return active branch
cd "${1}" 2> /dev/null || return 1
git describe --long --dirty --tags || return 1
}

if [[ "$2" == "remote" ]]; then

  if [[ "$3" == "reboot" ]]; then
    sleep 30
  fi

  GITHUB_CORE_VERSION="$(json_extract tag_name "$(curl -q 'https://api.github.com/repos/pi-hole/pi-hole/releases/latest' 2> /dev/null)")"
  GITHUB_WEB_VERSION="$(json_extract tag_name "$(curl -q 'https://api.github.com/repos/pi-hole/AdminLTE/releases/latest' 2> /dev/null)")"
  GITHUB_FTL_VERSION="$(json_extract tag_name "$(curl -q 'https://api.github.com/repos/pi-hole/FTL/releases/latest' 2> /dev/null)")"

  echo -n "${GITHUB_CORE_VERSION} ${GITHUB_WEB_VERSION} ${GITHUB_FTL_VERSION}" > "/etc/pihole/GitHubVersions"

else

  CORE_BRANCH="$(get_local_branch /etc/.pihole)"
  WEB_BRANCH="$(get_local_branch /var/www/html/admin)"
  FTL_BRANCH="$(pihole-FTL branch)"

  echo -n "${CORE_BRANCH} ${WEB_BRANCH} ${FTL_BRANCH}" > "/etc/pihole/localbranches"

  CORE_VERSION="$(get_local_version /etc/.pihole)"
  WEB_VERSION="$(get_local_version /var/www/html/admin)"
  FTL_VERSION="$(pihole-FTL version)"

  echo -n "${CORE_VERSION} ${WEB_VERSION} ${FTL_VERSION}" > "/etc/pihole/localversions"

fi