a suggestion for murkmod's future ChromeOS updater

omaha_update_test.sh

#!/bin/bash

lsbval() {
  local key="$1"
  local lsbfile="${2:-/etc/lsb-release}"

  if ! echo "${key}" | grep -Eq '^[a-zA-Z0-9_]+$'; then
    return 1
  fi

  sed -E -n -e \
    "/^[[:space:]]*${key}[[:space:]]*=/{
      s:^[^=]+=[[:space:]]*::
      s:[[:space:]]+$::
      p
    }" "${lsbfile}"
} # from rainestorme/murkmod (MIT License)

check_chromeos_update() {
  local appid=$(lsbval CHROMEOS_RELEASE_APPID)
  local version=$(lsbval CHROMEOS_RELEASE_VERSION)
  local arch=$(uname -m)
  local track=$(lsbval CHROMEOS_RELEASE_TRACK) # "stable-channel"
  local board=$(lsbval CHROMEOS_RELEASE_BOARD)
  local hardware_class=$(crossystem hwid)

  local OMAHA_URL="https://tools.google.com/service/update2"

  local REQUEST_DATA=$(cat <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<request protocol="3.0" version="ChromeOSUpdate-1.0" updaterversion="0.1.0.0" installsource="ondemandupdate" ismachine="1">
  <os platform="ChromeOS" version="$version" sp="$version_$arch" />
  <app appid="$appid" version="$version" board="$board" track="$track" hardware_class="$hardware_class">
    <updatecheck />
  </app>
</request>
EOF
  )

  local response=$(curl -s -X POST -H "Content-Type: application/xml" --data "$REQUEST_DATA" "$OMAHA_URL")
  local binary_url=$(echo "$response" | grep -o 'codebase="[^"]*"' | sed -e 's/codebase="//' -e 's/"//' | head -n 1)
  local binary_path=$(echo "$response" | grep 'event="update"' | grep -o 'run="[^"]*"' | sed -e 's/run="//' -e 's/"//' | head -n 1)
  if [ -z "$binary_path" ]; then
    return
  fi
  echo "$binary_url$binary_path"
}

check_chromeos_update