#!/bin/sh
# j2pa CGI script
# give it query params url= and (optionally) width=
# it will produce a text version of the image specified
# it will cache results in $cache_dir

# it requires:
#   curl    from http://curl.haxx.se/
#   convert from http://www.imagemagick.org/
#   jp2a    from http://jp2a.sourceforge.net/

PATH=/home/childrf6/bin:$PATH
cache_dir='/home/childrf6/public_html/jp2a/'
jp2a_args='--background=light'

echo -e 'Content-Type: text/plain\n\n'

default_width=600
max_width=800
min_width=1

case "$QUERY_STRING" in
  [0-9]/*|[0-9][0-9]/*|[0-9][0-9][0-9]/*)
    width=${QUERY_STRING%%/*}
    url=${QUERY_STRING#*/}
  ;;
  http://*|https://*)
    url=${QUERY_STRING}
  ;;
  *)
    while test -n "$QUERY_STRING"; do
      arg="${QUERY_STRING%%&*}"
      QUERY_STRING="${QUERY_STRING#$arg}"
      QUERY_STRING="${QUERY_STRING#&}"
      case "$arg" in
	url=*) url="${arg#url=}";;
	width=*) width="${arg#width=}";;
      esac
    done
  ;;
esac

let 'width>=min_width && width<=max_width' || width=$default_width

hash="$(echo "$url"|md5sum)"
cache="$cache_dir"/${hash%% *}-$width.txt.gz

case "$url" in
  http://*|https://*)
    if [ -f "$cache" ]; then
      exec gzip -cd "$cache"
    else
      # racey
      if curl -s "$url" | convert - jpg:- |
	 jp2a --width=$width $jp2a_args - | tee "${cache%.gz}";
      then
	gzip "${cache%.gz}"
      else
        rm "${cache%.gz}"
      fi
    fi
  ;;
  *) echo 'no url or bad url.' ;;
esac