Download chrome extension

download-chrome-extension.sh

#!/bin/bash
# work in progress

# Usage info
show_help() {
cat << EOF
Usage: ${0##*/} [-h] <-a APP_ID>...
Do stuff with FILE and write the result to standard output. With no FILE
or when FILE is -, read standard input.
  
  -h          display this help and exit
  -a APP_ID   downloading the crx file for the specified app id
EOF
}       

OPTIND=1


while getopts "h?a:" opt; do
    case "$opt" in
    h|\?)
        show_help
        exit 0
        ;;
    a)  app_id=$OPTARG
        ;;
    esac
done

shift $((OPTIND-1))

[ "$1" = "--" ] && shift

if [ "$app_id" ]
then
	base_download_url="https://clients2.google.com/service/update2/crx?response=redirect&prodversion=38.0&x=id%3DPUT_HERE_APP_ID%26installsource%3Dondemand%26uc"
	#app_id=mnieoidhfojjegnlioncpneloopflfde
	app_url=$(curl -s "https://chrome.google.com/webstore/detail/$app_id" |
	sed -e 's/<a /\n<a /gI' |
	grep -i '<a .*href=.*>' |
	sed -e 's/<a .*href=['"'"'"]//I' -e 's/["'"'"'].*$//I' -e '/chrome/ !d')

	app_details=$(curl -s $app_url |
	sed -e 's/<meta /\n<meta /gI' -e 's/\/>/\/>\n/ gI' |
	grep -Ei '<meta itemprop=\"name|version\".*>' |
	sed -e 's/<meta.*content=\"//g' -e 's/\" \/>//g')

	app_name=$(echo "$app_details" | sed -n '1 p' | sed -e 's/ /-/g')
	app_version=$(echo "$app_details" | sed -n '2 p')

	crx_download_url=$(sed "s/PUT_HERE_APP_ID/$app_id/g" <<< $base_download_url)

	echo app_id: $app_id
	echo app_url: $app_url
	echo app_name: $app_name
	echo app_version: $app_version
	echo base_download_url: $base_download_url
	echo crx_download_url: $crx_download_url

	crx_filename=$(echo "$app_name"_"$app_version".crx)

	curl_result=$(curl -s $crx_download_url)

	if (echo "$curl_result" | grep -qi "Moved")
	then
		crx_download_url=$(echo "$curl_result" | sed -e 's/<a /\n<a /gI' | grep -i '<a .*href=.*>' | sed -e 's/<a .*href=['"'"'"]//I' -e 's/["'"'"'].*$//I' -e '/google/ !d')
	fi

	curl -s -o "$crx_filename" $crx_download_url
else
	show_help
fi