SESSIONF - Session File Manager (useful for CGI scripts)

sessionf

#! /bin/sh
 
######################################################################
#
# SESSIONF - Session File Manager (useful for CGI scripts)
#
# USAGE: sessionf <subcommand> [argument] ...
#
# * List of Subcommands:
#   create ..... $0 create at=<template_path>
#      1) Create a new session file into/with <template_path> if possible.
#      2) Return the path of the session file with $?=0. ($?>0 when failure)
#   validate ... $0 validate <id> at=<template_path> lifemin=<life_minutes>
#      1) Validate the session file whose name is <id> in <template_path>.
#      2) return $?=0 when the file is valid. ($?>0 when invalid)
#      - To be valid, the session file must pass the 2 following check points.
#        1. Does the file exist?
#        2. Did the file modify within the last <life_minutes> minutes?
#   reuse ...... $0 avail <id> at=<template_path> lifemin=<life_minutes>
#      1) Validate the session file whose name is <id> in <template_path>.
#      2) Update the timestamp of the file.
#      3) Return the path with $?=0 when the file is valid. ($?>0 when invalid)
#   avail ...... $0 avail <id> at=<template_path> lifemin=<life_minutes>
#      1) Update the timestamp of the session file whose name is <id>
#         if it is valid. Otherwise, Create a new one.
#      2) Return the path of the available one with $?=0. ($?>0 when failure)
#   renew ...... $0 renew <id> at=<template_path> lifemin=<life_minutes>
#      1) Renew the session ID. (It means renaming the session file)
#      2) Update the timestamp of the file.
#      3) Return the nenewed file path with $?=0 when the original one is
#         valid. ($?>0 when invalid)
#   remove ..... $0 remove <id> at=<template_path> [lifemin=<life_minutes>]
#      1) Remove the session file in <template_path>.
#      2) Return $?=0 when succeed.
#      - Wildcard is available. Also return $?=0 when no file to remove found.
#      - When <life_minutes> is set, only the files which are older than that
#        are removed.
#
# * On "validate", "reuse" and "remove" subcommands, you can set the session
#   file directory in the <id> argument instead of the "at" argument.
#
# Written by Rich Mikan (richmikan[at]richlab.org) at 2014/06/27
#
######################################################################

# --- initalization --------------------------------------------------
PATH=/usr/bin:/bin
#
if [ \( -f "${0%/*}/mkstemp" \) -a \( -x "${0%/*}/mkstemp" \) ]; then
  CMD_MKTEMP="${0%/*}/mkstemp"
else
  CMD_MKTEMP='mktemp'
fi
#
print_usage_and_exit () {
  cat <<-__USAGE 1>&2
	Usage   : ${0##*/} <subcommand> [argument] ...
	Version : Fri Jun 27 07:07:46 JST 2014
__USAGE
  exit 1
}

# --- parse arguments ------------------------------------------------
subcmd=''
id=''
dir=''
idtmpl=''
lifemin=''
[ $# -ge 2 ] || print_usage_and_exit
echo "_$1" | grep '^_[a-z]\{1,\}$' >/dev/null || print_usage_and_exit
subcmd=$1
shift
if [ "$subcmd" != 'create' ]; then
  id=${1##*/}
  echo "_$1" | grep '/' >/dev/null && dir=${1%/*} && [ -z "$dir" ] && dir='/'
  shift
fi
for arg in "$@"; do
  case "$arg" in
    at=*)
      check=${arg#at=}
      if echo "_$check" | grep '/' >/dev/null; then
        dir=${check%/*} && [ -z "$dir" ] && dir='/'
        idtmpl=${check##*/}
      else
        dir='.'
        idtmpl=$check
      fi
      [ -d "$dir" ] || { echo "${0##*/}: directory not found"; exit 1; }
      ;;
    lifemin=*)
      echo "$arg" | grep '^lifemin=[0-9]\{1,\}$' >/dev/null || print_usage_and_exit
      lifemin=${arg#lifemin=}
      ;;
    *)
      print_usage_and_exit
      ;;
  esac
done
[ -n "$dir" ] || print_usage_and_exit

# --- subcommand routines --------------------------------------------
case $subcmd in
  create)
    [ -n "$idtmpl"  ] || print_usage_and_exit
    exec $CMD_MKTEMP "$dir/$idtmpl"
    ;;
  validate)
    [ -n "$lifemin" ] || print_usage_and_exit
    [ -f "$dir/$id" ] || exit 1
    find "$dir" -name "$id" -mmin +$lifemin | awk 'END{exit (NR>0) ? 1 : 0;}'
    exit $?
    ;;
  reuse)
    [ -n "$lifemin" ] || print_usage_and_exit
    [ -f "$dir/$id" ] || exit 1
    find "$dir" -name "$id" -mmin +$lifemin | awk 'END{exit (NR>0) ? 1 : 0;}'
    [ $? -eq 0      ] || exit 2
    touch "$dir/$id"
    echo "$dir/$id"
    exit 0
    ;;
  avail)
    [ -n "$lifemin" ] || print_usage_and_exit
    [ -n "$idtmpl"  ] || exit 1
    [ -f "$dir/$id" ] || exec $CMD_MKTEMP "$dir/$idtmpl"
    find "$dir" -name "$id" -mmin +$lifemin | awk 'END{exit (NR>0) ? 1 : 0;}'
    [ $? -eq 0      ] || exec $CMD_MKTEMP "$dir/$idtmpl"
    touch "$dir/$id"
    echo "$dir/$id"
    exit 0
    ;;
  renew)
    [ -n "$lifemin" ] || print_usage_and_exit
    [ -n "$idtmpl"  ] || print_usage_and_exit
    [ -f "$dir/$id" ] || exit 1
    find "$dir" -name "$id" -mmin +$lifemin | awk 'END{exit (NR>0) ? 1 : 0;}'
    [ $? -eq 0      ] || exit 2
    check=$($CMD_MKTEMP "$dir/$idtmpl" 2>/dev/null)
    [ $? -eq 0      ] || exit 3
    mv -f "$dir/$id" "$check"
    [ $? -eq 0      ] || exit 4
    touch "$check"
    echo "$check"
    exit 0
    ;;
  remove)
    if [ -n "$lifemin" ]; then
      find "$dir" -name "$id" -mmin +$lifemin | xargs rm -f
      exit $?
    else
      find "$dir" -name "$id"                 | xargs rm -f
      exit $?
    fi
    ;;
  *)
    print_usage_and_exit
    ;;
esac