sending document image or text into telegram channel with bot

telegram-bot

#!/usr/bin/env bash
## this script sending message into telegram channel

OSNAME=$(uname)

get_fullpath() {
  if [[ $OSNAME == "Linux" ]] ; then
    readlink -m $1
  elif [[ $OSNAME == "Darwin" ]] ; then
    realpath $1
  else
    echo $1
  fi
}

# checking for chatid
if [[ -z "$CHAT_ID" ]] ; then
  echo 'there are no CHAT_ID variable'
  echo 'invite @RawDataBot into your channel to see your chat id'
  exit 255
fi

# checking for bot token
if [[ -z "$BOT_TOKEN" ]] ; then
  echo 'there are no BOT_TOKEN variable'
  echo 'ask @botfather about your bot token'
  exit 255
fi

HOST=https://api.telegram.org

useArgument=1

# read from pipe
# this only work on linux
if test -p /proc/self/fd/0 -o -s /dev/stdin ; then
  useArgument=0
  args="text='$(cat -)'"
  endpoint="$HOST/bot$BOT_TOKEN/sendMessage"
elif test $# -eq 0; then
  echo 'Invalid argument'
  cat<<EOF
$0 - Send message into channel  on telegram
Usage:
        $0 <options> content
Example:
    Send image
        $0 photo /tmp/filename.jpg
    Send document
        $0 document /tmp/document.log
    Send text
        $0 this text will sending all of it.
    Sending text from stdout
        echo this text from stdout | $0

Options:
        photo, p, i, image -> opions for sending image
        document, d -> opions for sending document
EOF
exit
fi

if [[ $useArgument == 1 ]] ; then
  case $1 in
    photo|p|i|image)
      data=$(get_fullpath $2)
      args="photo=@$data"
      endpoint="$HOST/bot$BOT_TOKEN/sendPhoto"
      ;;
    document|d)
      data=$(get_fullpath $2)
      args="document=@$data"
      endpoint="$HOST/bot$BOT_TOKEN/sendDocument"
      ;;
    *)
      args="text='$@'"
      endpoint="$HOST/bot$BOT_TOKEN/sendMessage"
  esac
fi

#echo curl --progress -F chat_id=$CHAT_ID -F "$args" $endpoint
curl --progress -F chat_id=$CHAT_ID -F "$args" $endpoint