Recursively pre-compress (gzip) CSS/JavaScript/webfont assets for use Nginx and the HttpGzipStaticModule module.

pre-compress-web-assets

#!/bin/bash

###########################################################################
# Usage:
#        pre-compress-web-assets [.|folder_name]
#
# This script will recursively look for the files in the $ext variable
# and compress/re-compress them.
# 
# By default it will look into the current working folder, 
# but one can provide a path for the script to crawl.
#
###########################################################################
# Flags

set -e # break on error.
set -u # break on using undefined variable.

###########################################################################
# Settings

VERSION=20160425172300

###########################################################################

base_name=$(basename "${0}")

print_fail() {
    echo "$*"
    exit1
}

self_update() {

    gits_url='https://gist.githubusercontent.com/rabin-io/63000f48d1f9170f17ea5f73bcf84d66/raw/pre-compress-web-assets'
    full_path=$(realpath "${0}")
    
    tempfile=$(mktemp "/tmp/${base_name}.XXXXXX")
    wget -q "${gits_url}" -O "${tempfile}"

    gits_version=$(grep  "^VERSION=" "${tempfile}"  | awk -F'=' '{print $2}')
    local_version=$(grep "^VERSION=" "${full_path}" | awk -F'=' '{print $2}')

    if [[ ${gits_version} -ge ${local_version} ]];
        then      
        cp -v "${tempfile}" "${full_path}"
    else
        echo "Nothing to update."
        exit 1
    fi

}

compressResource() {

    gzip -c9 "${1}" > "${1}.gz"
    touch -c --reference="${1}" "${1}.gz"

    echo "Compressed: ${1} > ${1}.gz"
}

if [[ $1 == '--selfupdate' || $1 == '--self-update' ]]; then
    self_update
else

    appDir=${1-${PWD?WTF}}
    echo "Preocessing ${appDir}"

    ext="css|js|eot|svg|ttf|woff"

    # fetch all existing gzipped CSS/JavaScript/webfont files and remove files that do not have a base uncompressed file
    find "$appDir" -type f -regextype posix-extended -iregex ".*\.(${ext})\.gz$" -print0 | while read -d '' compressFile 
    do
        if [[ ! -f ${compressFile%.gz} ]]; 
            then
                # remove orphan gzipped file
                rm "${compressFile}" && echo "Removed: ${compressFile}"
            fi
        done

    # fetch all source CSS/JS/webfont files - excluding *.src.* variants (pre-minified CSS/JavaScript)
    # gzip each file and give timestamp identical to that of the uncompressed source file
    find "$appDir" -type f -regextype posix-extended \( -iregex ".*\.(${ext})$" \) \( ! -name "*.src.css" -and ! -name "*.src.js" \) -print0 | while read -d '' sourceFile 
    do
        if [[ -f "${sourceFile}.gz" ]]; 
            then
                # only re-gzip if source file is different in timestamp to the existing gzip file
                if [[ (${sourceFile} -nt "${sourceFile}.gz") || (${sourceFile} -ot "${sourceFile}.gz") ]]; then
                    # re-compress
                    compressResource "${sourceFile}"
                fi
            else
                compressResource "${sourceFile}"
            fi
        done
#        
fi