server

#!/bin/sh

# Usage: $0 [-w] [-s SERVER] [PORT]
# Start a Kingdom Index web server (by default, use port is 8888)
#
# Web server can be either:
# python  => python3's http.server (typically installed on linux distro)
# busybox => busybox's httpd       (installed in termux on an Android tablet)
# if not specified, it will try python first, then busybox
#
# Server will serve locally only to 127.0.0.1 by default,
# but if -w flag, it will serve to all. In that latter case, URL is also written
# as a QR code which can be useful to connect a tablet (requires qrencode)


PORT=8888

#--- UTILITY FUNCTIONS ---------------------------------------------------------

exists() { command -v "$@" >/dev/null ; }

show()   {
   printf "Starting web server '%s'.\n" "$1"

   # determine IP address (assumes a 192.168.x.0/24 LAN)
   IP=''
   if exists ifconfig; then
      IP=$(ifconfig | awk '/192.168./ {print $2; exit}')
   elif exists ip; then
      IP=$(ip addr  | awk '/192.168./ {print $2; exit}' | cut -d/ -f1)
   fi
   [ -z "$IP" ] && IP=127.0.0.1

   # prints URL, possibly as a QR code too
   URL="http://127.0.0.1:$PORT/start.html"
   printf "Connect from this host to: %s\n" "$URL"
   if $LOCAL || [ "$IP" = 127.0.0.1 ]; then
      echo
   else
      URL="http://$IP:$PORT/start.html"
      printf 'or from your LAN to      : %s\n' "$URL"
      exists qrencode && qrencode -t ANSIUTF8 -o - "$URL"
   fi
}

#-------------------------------------------------------------------------------


cd app || { echo 'cannot cd to app' >&2; exit 1; }

SERVER=''
LOCAL=true
while true; do
   case $1 in
      -w) LOCAL=false ;;
      -s) shift
          case $1 in
             busybox) SERVER=busybox ;;
             python*) SERVER=python  ;;
                   *) echo "server '$1' not supported" >&2
                      exit 1         ;;
          esac  ;;
       *) break ;;
   esac
   shift
done

if [ -z "$SERVER" ]; then
   if   exists python3; then  SERVER=python
   elif exists busybox; then  SERVER=busybox
   else echo 'cannot find a web server' 2>&1; exit 1
   fi
fi

[ -n "$1" ] && PORT=$1


set --
case $SERVER in
    busybox) if busybox --list | grep -q '^httpd$'; then
                show  'busybox'
                if $LOCAL
                   then set -- -p "127.0.0.1:$PORT"
                   else set -- -p "$PORT"
                fi
                busybox httpd -vv -f "$@"
             else
                echo "busybox doesn't have httpd applet" 2>&1
                exit 1
             fi ;;

     python) show  'python3'
             $LOCAL && set -- --bind '127.0.0.1'
             python3 -m http.server --cgi "$@" "$PORT"
             ;;
esac