optimg

#!/usr/bin/env bash
#
# Optimize images by compressing & renaming.
#
# Paul Esch-Laurent <p@uly.io>
# MIT
#
# Requires `imagemin`: npm i -g imagemin-cli

# Strict settings
set -o errexit
set -o pipefail
set -o nounset

# Magic variables
__dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
__file="${__dir}/$(basename "${BASH_SOURCE[0]}")"
__base="$(basename "${__file}" .sh)"

# Output directory
OUT_DIR="_optimg"

# Print out usage information
usage() {
  cat <<HEREDOC
Usage:
  ${__base} <files>

  <files> can be individual files or globs (e.g. *.jpg, foo/*).

Options:
  -h --help    Show this.
  -r --rename  Just rename, don't compress.
HEREDOC
}

# Check for required binary
check_reqs() {
  if [[ ! $(type -P "imagemin") ]]; then
    echo "'imagemin' required. Install with npm: npm i -g imagemin-cli"
    exit 1
  fi
}

# Create output directory if necessary
create_directory() {
  if [[ ! -d "${OUT_DIR}" ]]; then
    mkdir -p "${OUT_DIR}"
    echo "Created output directory: ${OUT_DIR}"
  fi
}

# Rename 'em up
rename_images() {
  create_directory
  for file in "${@:-}"; do

    # It's probably an image and it's not a directory
    if file "${file}" | grep -qE 'image|bitmap' && [[ ! -d "${file}" ]]; then

      # First 7 characters of SHA2 hash
      hash="$(openssl sha256 "${file}" | tr -d '\n' | tail -c 64 | head -c 7)"
      full="$(basename "${file}")"
      # Get extension (... and convert jpeg -> jpg)
      ext="$(echo "${full##*.}" | sed -e 's/e//g')"
      # Remove non- alphanumerics, periods, underscores, and dashes
      name="$(echo "${full%.*}" | sed -e 's/[^A-Za-z0-9._-]//g')"
      echo "Renaming ${file}"

      cp "${file}" "${OUT_DIR}/${name}.${hash}.${ext,,}"
    fi
  done
}

# Optimize (compress & rename) 'em up
optimize_images() {
  create_directory
  pids=()

  for file in "${@:-}"; do

    # It's probably an image and it's not a directory
    if file "${file}" | grep -qE 'image|bitmap' && [[ ! -d "${file}" ]]; then

      # First 7 characters of SHA2 hash
      hash="$(openssl sha256 "${file}" | tr -d '\n' | tail -c 64 | head -c 7)"
      full="$(basename "${file}")"
      # Get extension (... and convert jpeg -> jpg)
      ext="$(echo "${full##*.}" | sed -e 's/e//g')"
      # Remove non- alphanumerics, periods, underscores, and dashes
      name="$(echo "${full%.*}" | sed -e 's/[^A-Za-z0-9._-]//g')"
      echo "Optimizing ${file}"

      imagemin "${file}" > "${OUT_DIR}/${name}.${hash}.${ext,,}" &
      pids+=("${!}")
    fi
  done

  for pid in "${pids[@]}"; do
    wait "${pid}"
  done
}

# Drive it
main() {
  check_reqs
  # Parse args
  if [[ -z "${1:-}" ]]; then
    usage
  elif [[ "${1:-}" =~ ^-h|--help$ ]]; then
    usage
  elif [[ "${1:-}" =~ ^-r|--rename$ ]]; then
    shift
    rename_images "${@:-}"
  else
    optimize_images "${@:-}"
  fi
}

# Call it
main "${@:-}"