version_append.sh

#!/bin/bash

# This is used to help with file caching.
# Most browsers cache JS file, meaning that when a new version is pushed
# perople visiting the page will load the cached JS file, thus
# not seeing any of the changes from the update.
# This appends a hash to each local path in index.html and /dist.elm.js
# meaning that files can be cached for arbitrarily long amounts of time
# but still detect and load new versions when changed on the server
# this script is run automatically as part of the dockerfile

shopt -s globstar

#changeFiles='./public/css/blur.css ./public/dist/elm.js ./public/index.html'
changeFiles=("./public/css/blur.css")

for file in $changeFiles
do
    files=()
    paths=()
    j=0
    for i in ./public/**/*
    do
        if [ -f "$i" ];
        then
            #printf "Path: %s\n" "${i##/*}" # shortest suffix removal
            hash=`sha256sum "${i##/*}" | awk '{ print $1 }'`
            #hash= sha256sum "${i}"
            noSrc=${i/'./src'/} # remove src
            noPublic=${noSrc/'./public'/}
            if [[ $noPublic == /* ]]
            then
                paths[$j]="${noPublic}"
                files[$j]="$noPublic?v=${hash:0:12}"
                j=$((j+1))
            fi
        fi
    done
    # Update the html and elm files
    modify=`cat $file`
    echo $modify
    for i in $(seq 0 $j)
    do
        old_name=${paths[$i]}
        new_name=${files[$i]}
        modify=${modify//$old_name/$new_name}
    done
    echo "----------"
    echo $modify
    #echo $modify > $file
done