Convert files into base64 data URLs or extract underlying data from data URLs.

file2url.sh

#! /bin/bash
#=======================================================================================#
#
#     ___________.___.____     ___________________  ____ _____________.____     
#     \_   _____/|   |    |    \_   _____/\_____  \|    |   \______   \    |    
#      |    __)  |   |    |     |    __)_  /  ____/|    |   /|       _/    |    
#      |     \   |   |    |___  |        \/       \|    |  / |    |   \    |___ 
#      \___  /   |___|_______ \/_______  /\_______ \______/  |____|_  /_______ \
#          \/                \/        \/         \/                \/        \/
#
#=======================================================================================#
#
# FILE2URL
#
#   Convert files into base64 data URLs or extract underlying data from data URLs.
#
#   This script can process both remote files (URL's) and local file references.
#   All outputs are sent directly to the terminal.
#
#   (Created by h8rt3rmin8r on 20190207)
#
# USAGE
#   _______________________________________________________________________________
#  |                                |                                              |
#  | [ Command ]                    |  [ Outcome ]                                 |
#  |________________________________|______________________________________________|
#  |                                |                                              |
#  | ./file2url.sh <URL>            |  Encode a remote file located at <URL>       |
#  |                                |                                              |
#  | ./file2url.sh <FILE>           |  Encode a local file located at <FILE>       |
#  |                                |                                              |
#  | echo <DAT> | ./file2url.sh     |  Decode an encoded data URL, <DAT>           |
#  |________________________________|______________________________________________|
#
#=======================================================================================#

# VARIABLE DECLARATIONS

DT="`date '+%Y%m%d%H%M%S'`"
SRC="$1"
DL="${DT}-download"
SELF="[file2url]"
VB_H="Use '--help' for more information."
VB_E01="ERROR: No input detected! ${VB_H}"
VB_E02="ERROR: Input was not a file or valid URL reference! ${VB_H}"

# FUNCTION DECLARATIONS

function help_text() {
    # Script help text function
    clear
    echo
    cat $0 | head -n 34 | tail -n +2 | grep '^#' | tr '#' ' '
    return
}

function check_mime() {
    # Check the mime type of a designated file
    file --mime-type -b "$1"
    return
}

function run_remote() {
    # Process a remote image file
    wget -q -O "${DL}" "${SRC}"
    MIME_TYPE="$(check_mime ${DL})"
    OUT_A=$(echo "data:${MIME_TYPE};base64,")
    OUT_B=$(cat "${DL}" | base64 | tr -d '\n')
    echo "${OUT_A}${OUT_B}" | tr -d '\n'
    rm "${DL}" &>/dev/null
    return
}

function run_local() {
    # Process a local image file
    MIME_TYPE="$(check_mime ${SRC})"
    OUT_A=$(echo "data:${MIME_TYPE};base64,")
    OUT_B=$(cat "${SRC}" | base64 | tr -d '\n')
    echo "${OUT_A}${OUT_B}" | tr -d '\n'
    return
}

# INPUT VALIDATION AND OPERATIONS EXECUTION

if [[ -t 0 ]];
then
    if [[ "x${SRC}" == "x" ]]; then echo "${SELF} ${VB_E01}"; exit 1; fi
    if [[ "${SRC}" == "-h" || "${SRC}" == "-help" || "${SRC}" == "--help" ]];
    then
        help_text
        exit 0
    fi
    if [[ -f "${SRC}" ]]; then run_local; exit 0; fi
    if [[ "$(echo -n ${SRC} | grep '^http' | wc -c)" -gt 4 && "${SRC}" =~ '://' ]];
        then run_remote; exit 0
        else echo "${SELF} ${VB_E02}"; exit 1
    fi
else
    echo -n $(< /dev/stdin) | cut -d ',' -f2 | base64 -d
    exit 0
fi

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