Add book-reader: two-page image book viewer

Browser viewer for books stored as folders of page images: two-page
spreads with a GPU-composited 3D page turn, keyboard/wheel/click
navigation, fit-height and fit-width (scroll then flip) modes, a library
of every image folder under the configured root, and per-book reading
progress in localStorage.

rc.book-reader serves it with python3 http.server on 127.0.0.1 from a
runtime dir of symlinks, so the library is never written to. It can be
copied to /etc/rc.d: started as root it re-executes itself as RUNAS.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/rc.book-reader b/rc.book-reader
new file mode 100755
index 0000000..5ba30a3
--- /dev/null
+++ b/rc.book-reader
@@ -0,0 +1,61 @@
+#!/bin/bash
+# rc.book-reader: start/stop the local server for book-reader.
+# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Config (shell syntax): ${XDG_CONFIG_HOME:-~/.config}/book-reader.conf
+#   LIBRARY=/path/to/collection   # required; every folder with images inside is a book
+#   PORT=8642                      # keep it fixed: reading progress is stored per origin
+#   BIND=127.0.0.1
+#   READER=/path/to/book-reader/reader.html  # needed when this script is copied out of the repo
+#
+# Boot (Slackware): copy to /etc/rc.d, set RUNAS below, call "start" from
+# rc.local and "stop" from rc.local_shutdown. Run as root, the script
+# re-executes itself as RUNAS: the web server never runs as root.
+
+RUNAS=      # user to run as when started by root
+
+if [ "$(id -u)" = 0 ]; then
+  if [ -z "$RUNAS" ] || [ "$RUNAS" = root ]; then echo "set RUNAS in $0 to a non-root user" >&2; exit 1; fi
+  exec su - "$RUNAS" -s /bin/bash -c "$(printf '%q %q' "$(readlink -f "$0")" "$1")"
+fi
+
+LIBRARY= PORT=8642 BIND=127.0.0.1 READER=$(dirname "$(readlink -f "$0")")/reader.html
+CONF=${BOOK_READER_CONF:-${XDG_CONFIG_HOME:-$HOME/.config}/book-reader.conf}
+[ -r "$CONF" ] && . "$CONF"
+
+# fixed path: boot (no XDG_RUNTIME_DIR) and desktop sessions must share the pidfile
+RUN=/tmp/book-reader-$UID
+PIDFILE=$RUN/pid
+URL="http://$BIND:$PORT/reader.html"
+
+running() { [ -f "$PIDFILE" ] && kill -0 "$(cat "$PIDFILE")" 2>/dev/null; }
+
+start() {
+  if running; then echo "book-reader already running: $URL"; return 0; fi
+  if [ ! -d "$LIBRARY" ]; then echo "LIBRARY not set or missing (edit $CONF)" >&2; return 1; fi
+  if [ ! -r "$READER" ]; then echo "reader.html not found at $READER (set READER in $CONF)" >&2; return 1; fi
+  # Served root holds only symlinks: the viewer and the library, so neither dir gets touched.
+  mkdir -p -m 700 "$RUN" "$RUN/root"
+  find "$RUN/root" -mindepth 1 -maxdepth 1 -type l -delete
+  ln -s "$(readlink -f "$READER")" "$RUN/root/reader.html"
+  ln -s "$(readlink -f "$LIBRARY")" "$RUN/root/$(basename "$LIBRARY")"
+  setsid python3 -m http.server -b "$BIND" -d "$RUN/root" "$PORT" >"$RUN/log" 2>&1 &
+  echo $! >"$PIDFILE"
+  sleep 0.5
+  if ! running; then echo "book-reader failed to start:" >&2; tail -n 5 "$RUN/log" >&2; rm -f "$PIDFILE"; return 1; fi
+  echo "book-reader started: $URL"
+}
+
+stop() {
+  if running; then kill "$(cat "$PIDFILE")"; echo "book-reader stopped"; else echo "book-reader not running"; fi
+  rm -f "$PIDFILE"
+}
+
+case "$1" in
+  start) start ;;
+  stop) stop ;;
+  restart) stop; start ;;
+  status) if running; then echo "book-reader running: $URL"; else echo "book-reader stopped"; exit 3; fi ;;
+  *) echo "usage: $0 start|stop|restart|status" >&2; exit 1 ;;
+esac