net

#!/bin/bash

# Copyright (C) 2015 Benjamin Abendroth
# 
# 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 3 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

################################################################################
# Net functions ################################################################
################################################################################

valid_http_link () {
  local LINK="${1:?$FUNCNAME: Missing argument}"

  local PROTOCOL='(.+://)?'
  local USER_PASS='((.+)(:.+)?@)?'
  local _HOST='([a-zA-Z0-9\.-]+)'
  local PORT='(:[0-9]+)?'
  local _PATH='([^\?#]+)?'
  local QUERY='(\?[^#]*)?'
  local FRAGMENT='(#.*)?'

  # protocol://username:password@hostname/path?query&arg=value#fragment
  grep -qE "$PROTOCOL$USER_PASS$_HOST$PORT$_PATH$QUERY$FRAGMENT" <<< "$LINK"
}

parse_url () {
  local WHAT="${1:?$FUNCNAME: Missing argument}"
  local LINK="${2:?$FUNCNAME: Missing argument}"
  local X=0 PART=""

  local PROTOCOL='(.+://)?'
  local USER_PASS='((.+)(:.+)?@)?'
  local HOST='([a-zA-Z0-9\.-]+)'
  local PORT='(:[0-9]+)?'
  local _PATH='([^\?#]+)?'
  local QUERY='(\?[^#]*)?'
  local FRAGMENT='(#.*)?'

  case ${WHAT,,} in
      proto*) X=1 ;;
       user*) X=3 ;;
       pass*) X=3 ;;
       host*) X=5 ;;
        port) X=6 ;;
        path) X=7 ;;
       query) X=8 ;;
    fragment) X=9 ;;
           *) return 1 ;;
  esac

  # protocol://username:password@hostname/path?query&arg=value#fragment
  PART=`sed -r "s|$PROTOCOL$USER_PASS$HOST$PORT$_PATH$QUERY$FRAGMENT|\\\\$X|g" <<< "$LINK"`

  case ${WHAT,,} in
      proto*) printf "${PART%://}" ;;
       user*) printf "${PART%:*}"  ;;
       pass*) printf "${PART#*:}"  ;;
       host*) printf "${PART}"     ;;
        port) printf "${PART#:}"   ;;
        path) printf "${PART}"     ;;
       query) printf "${PART#\?}"  ;;
    fragment) printf "${PART#\#}"  ;;
  esac

  printf "\n"
}

get_location () {
  local LINK="${1:?$FUNCNAME: Missing argument}"
  local DOMAIN=`grep -Eo 'https?://[^/]+' <<< "$LINK"`
  local LOCATION=""

  LOCATION=`wget -S -qO/dev/null "$LINK" 2>&1 | grep Location: | tail -1 | sed 's/ *Location: *//'`

  if [[ -z "$LOCATION" ]] ; then
    echo "$LINK"
  elif [[ ${LOCATION:0:1} = "/" ]] ; then
    echo "$DOMAIN$LOCATION"
  else
   echo "$LOCATION"
  fi
}