Bash script to get chrome extension

crx-getter.sh

#!/bin/bash
# Created by Likhith Chitneni (chittti)
# Thanks to Rob Wu for crxviewer (https://github.com/Rob--W/crxviewer)

# This bash script takes in command line arguments too!
# Arguments can be passed in as 
# ./crx-getter.sh <extension-ID> <chrome-version> <OS(1-6)> <arch(1-3)> <chrome(1)/chromium(2)> <stable(1)/unknown(2)>
# Only <extension-id> and <chrome-version> are mandatory, the rest default to linux, x86-64, chrome, stable respectively

if [[ $# -eq 0 ]]; then

  echo "Enter extension ID:"

  read EXTENSION_ID

  if [[ ${#EXTENSION_ID} -ne 32 ]]; then
    echo "Invalid extension ID"
    exit 1
  fi

  echo "Enter chrome version:"

  read PRODVERSION

  VERSION_DOTS="${PRODVERSION//[^.]}"

  if [[ ${#VERSION_DOTS} -ne 3 ]]; then
    echo "Invalid version number"
    exit 1
  fi

  # More details about OS, arch, and Nacl arch can be found at:
  # https://developer.chrome.com/extensions/runtime
  echo "What OS do you want the extension for? (Defaults to linux)"
  echo "(1) Linux"
  echo "(2) Windows"
  echo "(3) macOS"
  echo "(4) ChromeOS"
  echo "(5) Android"
  echo "(6) OpenBSD"

  read OS_CODE

  case $OS_CODE in 
    2)
        OS="win"
        ;;
    3)
        OS="mac"
        ;;
    4)
        OS="cros"
        ;;
    5)
        OS="android"
        ;;
    6)
        OS="openbsd"
        ;;
    *)
        OS="linux"
        ;;
  esac

  # Prompts only once for system arch and Nacl arch 
  echo "What arch do you want the extension for? (Defaults to x86-64)"
  echo "(1) x86-64"
  echo "(2) x86-32"
  echo "(3) arm"

  read ARCH_CODE

  case $ARCH_CODE in 
    2)
        ARCH="x86-32"
        NACL_ARCH="x86-32"
        ;;
    3)
        ARCH="arm"
        NACL_ARCH="arm"
        ;;
    *)
        ARCH="x86-64"
        NACL_ARCH="x86-64"
        ;;
  esac

  # @NOTE: PROD can be altogether omitted, but lets not do that 
  echo "Chrome or Chromium? (Defaults to chrome)"
  echo "(1) Chrome"
  echo "(2) Chromium"

  read CHROME_CODE

  case $CHROME_CODE in
    2)
        PROD="chromiumcrx"
        ;;
    *)
        PROD="chromecrx"
        ;;
  esac

  # @NOTE: Can also use "unknown" for PRODCHANNEL
  echo "Channel: Stable or unknown? (Defaults to stable)"
  echo "(1) Stable"
  echo "(2) Unknown"

  read PRODCHANNEL_CODE

  case $CHROME_CODE in
    2)
        PRODCHANNEL="unknown"
        ;;
    *)
        PRODCHANNEL="stable"
        ;;
  esac

else

  if [[ ${#1} -ne 32 ]]; then
    echo "Invalid extension ID"
    exit 1
  fi

  EXTENSION_ID=$1

  VERSION_DOTS="${2//[^.]}"

  if [[ ${#VERSION_DOTS} -ne 3 ]]; then
    echo "Invalid version number"
    exit 1
  fi

  PRODVERSION=$2

  case $OS_CODE in 
    2)
        OS="win"
        ;;
    3)
        OS="mac"
        ;;
    4)
        OS="cros"
        ;;
    5)
        OS="android"
        ;;
    6)
        OS="openbsd"
        ;;
    *)
        OS="linux"
        ;;
  esac

  case $4 in 
    2)
        ARCH="x86-32"
        NACL_ARCH="x86-32"
        ;;
    3)
        ARCH="arm"
        NACL_ARCH="arm"
        ;;
    *)
        ARCH="x86-64"
        NACL_ARCH="x86-64"
        ;;
  esac

  case $5 in
    2)
        PROD="chromiumcrx"
        ;;
    *)
        PROD="chromecrx"
        ;;
  esac

  case $6 in
  2)
      PRODCHANNEL="unknown"
      ;;
  *)
      PRODCHANNEL="stable"
      ;;
  esac
fi

URL='https://clients2.google.com/service/update2/crx?response=redirect'
URL+='&os='
URL+=$OS
URL+='&arch='
URL+=$ARCH
URL+='&nacl_arch='
URL+=$NACL_ARCH
URL+='&prod='
URL+=$PROD
URL+='&prodchannel='
URL+=$PRODCHANNEL
URL+='&prodversion='
URL+=$PRODVERSION
URL+='&x=id%3D'
URL+=$EXTENSION_ID
URL+='%26uc'

wget -O ${EXTENSION_ID}-${PRODVERSION}-${PRODCHANNEL}-${PROD::${#PROD}-3}-${OS}-${ARCH}.zip $URL