eeshow-viewer

#!/bin/sh
# eeshow-viewer - Caching wrapper for document viewers
#
# Written 2016 by Werner Almesberger
# Copyright 2016 by Werner Almesberger
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#

#
# Known issues:
# - should only cache things we can expect to be able to properly use locally,
#   e.g., PDF, text, etc., not Web pages
#

default_dir=$HOME/.eeshow-viewer-cache


usage()
{
	cat <<EOF 1>&2
usage: $0 [-c] [-m] [URL]

  -c  cache only, without starting a viewer
  -m  create the cache directory (default: $default_dir)
EOF
	exit 1
}


make_cache=false
cache_only=false
while [ "$1" ]; do
	case "$1" in
	-c)	cache_only=true;;
	-m)	make_cache=true;;
	-*)	usage;;
	*)	break;;
	esac
	shift
done

dir=${EESHOW_VIEWER_CACHE:-$default_dir}

if [ ! -d "$dir" ]; then
	if $make_cache; then
		mkdir -p "$dir" || exit 1
	else
		echo "no cache directory \"$dir\"" 1>&2
		echo "run  eeshow-viewer -m  to create" 1>&2
		exit 1
	fi
fi

[ "$1" ] || exit 0

url=${1%\#[0-9]*}
page=
if [ "$url" != "$1" ]; then
	page=${1##*#}
fi

hash=`echo -n "$url" | tr -c '[[:alnum:].\-]' _`
file=$dir/$hash
if [ ! -r "$file" ]; then
	wget -O "$file" "$url" || { rm -f "$file"; exit 1; }
fi

$cache_only && exit

if [ "$page" ]; then
	v=${EESHOW_PDF_VIEWER:-${PDF_VIEWER:-xdg-open}}
	case "$v" in
	*xpdf)	"$v" "$file" "$page";;
	*evince)"$v" --page-index="$page" "$file";;
	*)	"$v" "$file";;
	esac
else
	${EESHOW_VIEWER_VIEWER:-xdg-open} "$file"
fi