telegram

#!/bin/bash

#    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/>.

VERSION="0.4"
TOKEN=""
CHATS=()
DEBUG=false
DRY_RUN=false

IMAGE_FILE=""
DOCUMENT_FILE=""
PARSE_MODE=""
CODE_MODE=0
CRON_MODE=0
ACTION=""
TITLE=""
DISABLE_WEB_PAGE_PREVIEW=false
DISABLE_NOTIFICATION=false

URL="https://api.telegram.org/bot"
FILE_URL="https://api.telegram.org/file/bot"
CURL_OPTIONS="-s"

HAS_JQ=false
hash jq >/dev/null 2>&1 && HAS_JQ=true


function help {
	version
	echo "Usage: $0 [options] [message]"
	echo
	echo "OPTIONS are:"
	echo "    -t <TOKEN>       Telegram bot token to use. See ENVIRONMENT for more information."
	echo "    -c <CHAT_ID>     Chat to use as recipient. Can be given more than once. See ENVIRONMENT for more information."
	echo "    -f <FILE>        Sends file."
	echo "    -i <FILE>        Sends file as image. This will fail if the file isn't an actual image file."
	echo "    -M               Enables Markdown processing at telegram."
	echo "    -H               Enables HTML processing at telegram."
	echo "    -C               Sends text as monospace code. Useful when piping command outputs into this tool."
	echo "    -r               Like -C, but if the first line starts with '+ ', it is specially formatted."
	echo "    -T <TITLE>       Sets a title for the message. Printed in bold text if -M or -H is used."
	echo "    -l               Fetch known chat_ids."
	echo "    -R               Receive a file sent via telegram."
	echo "    -D               Sets disable_web_page_preview parameter to, well, disable the preview for links to webpages."
	echo "                     Can also be set in config as TELEGRAM_DISABLE_WEB_PAGE_PREVIEW=true (see ENVIRONMENT)"
	echo "                     This feature is only supported for text messages, not when sending files or images (-f, -i)."
	echo "    -N               Diables notifications on clients. Users will receive a notification with no sound."
	echo "                     Can also be set in config as TELEGRAM_DISABLE_NOTIFICATION=true (see ENVIRONMENT)"
	echo "    -m               Outputs the last received message. Format is: <Message ID> <Sender ID> <Chat ID> <Text>"
	echo
	echo "DEBUGGING OPTIONS are:"
	echo "    -v               Display lots of more or less useful information."
	echo "    -j               Pretend you don't have JQ installed."
	echo "    -n               Dry-run - don't send messages, only print them on screen."
	echo
	echo "Message can be '-', in that case STDIN will be used."
	echo
	echo "ENVIRONMENT"
	echo "    TOKEN and CHAT_ID are required. You can set them in four different ways:"
	echo "      1) globally in /etc/telegram.sh.conf"
	echo "      2) user-local in ~/.telegram.sh"
	echo "      3) user-local in ~/.telegram.sh.conf"
	echo "      4) via environment variables TELEGRAM_TOKEN and TELEGRAM_CHAT"
	echo "      5) via options -t and -c"
	echo "    Later methods overwrite earlier settings, so you can easily override global settings."
	echo "    Please be aware that you shuld keep your telegram token secret!"
	echo
	exit
}

function version {
	echo "telegram.sh version $VERSION"
	echo "by Fabian Schlenz"
}

function list_chats {
	log "$URL$TOKEN"
	response=`curl $CURL_OPTIONS $URL$TOKEN/getUpdates`
	log "$response"

	if [ "$HAS_JQ" = true ]; then
		echo "These are the available chats that I can find right now. The ID is the number at the front."
		echo "If there are no chats or the chat you are looking for isn't there, run this command again"
		echo "after sending a message to your bot via telegram."
		echo
		jq -r '.result | .[].message.chat | "\(.id|tostring) - \(.first_name) \(.last_name) (@\(.username))"' 2>/dev/null <<< "$response" || {
			echo "Could not parse reponse from Telegram."
			echo "Response was: $response"
			exit 1
		}
	else
		echo "You don't have jq installed. I'm afraid I can't parse the JSON from telegram without it."
		echo "So I'll have you do it. ;-)"
		echo
		echo "Please look for your chat_id in this output by yourself."
		echo 'Look for something like "chat":{"id":<CHAT_ID> and verify that first_name, last_name and'
		echo "username match your expected chat."
		echo
		echo "If there are no chats listed or the chat you are looking for isn't there, try again after"
		echo "sending a message to your bot via telegram."
		echo
		echo $response
	fi
}

function receive_message {
	if [ "$HAS_JQ" = false ]; then
		echo "You need to have jq installed in order to be able to receive messages."
		exit 1
	fi
	
	result=`curl $CURL_OPTIONS $URL$TOKEN/getUpdates?allowed_updates=message`
	log "$result"
	if [ "`jq '.result' <<< "$result"`" = "[]" ]; then
		echo "No recent messages."
		exit 1
	fi
	
	jq -r '.result[-1].message | [(.message_id|tostring), (.from.id|tostring), (.chat.id|tostring), .text] | join(" ")' <<< "$result"
	exit 0
}
		

function receive_file {
	if [ "$HAS_JQ" = false ]; then
		echo "You need to have jq installed in order to be able to download files."
		exit 1
	fi

	result=`curl $CURL_OPTIONS $URL$TOKEN/getUpdates?allowed_updates=message`
	log "$result"
	# {"ok":true,"result":[
	#   {
	#     "update_id":441727866,
	#     "message":{
	#       "message_id":8339,
	#       "from":{"id":15773,"is_bot":false,"first_name":"Fabian","last_name":"Schlenz","username":"fabianonline","language_code":"de"},
	#       "chat":{"id":15773,"first_name":"Fabian","last_name":"Schlenz","username":"fabianonline","type":"private"},
	#       "date":1526564127,
	#       "document":{"file_name":"desktop.ini","file_id":"BQAav-HkXugI","file_size":282}}}]}
	file_id=`jq -r '.result[-1].message.document.file_id' <<< "$result"`
	log "file_id: $file_id"
	if [ "$file_id" == "null" ]; then
		echo "Last message received apparently didn't contain a file. Aborting."
		exit 1
	fi
	file_name=`jq -r '.result[-1].message.document.file_name' <<< "$result"`
	log "file_name: $file_name"
	result=`curl $CURL_OPTIONS $URL$TOKEN/getFile?file_id=$file_id`
	log $result
	# {"ok":true,"result":{"file_id":"BQAav-HkXugI","file_size":282,"file_path":"documents/file_271.ini"}}
	path=`jq -r '.result.file_path' <<< "$result"`
	log "path: $path"
	if [ "$path" == "null" ]; then
		echo "Could not parse telegram's response to getFile. Aborting."
		exit 1
	fi
	file_name="`date +%s`_$file_name"
	log "file_name: $file_name"
	if [ -e "$file_name" ]; then
		echo "File $file_name already exists. This is unexpected, so I'm quitting now."
		exit 1
	fi
	curl $FILE_URL$TOKEN/$path --output "$file_name"
	echo "File downloaded as $file_name"
}

function log {
	[ "$DEBUG" = true ] && echo "DEBUG: $1"
}

function check_file {
	if [ ! -e "$1" ]; then
		echo "The file $1 does not exist."
		exit 1
	fi

	size=$(stat -c%s "$1")
	if (( size > 52428800 )); then
		echo "File $1 is breaking the file size limit imposed on Telegram bots (currently 50MB)."
		exit 1
	fi
}

function escapeMarkdown {
	res="${1//\*/∗}"
	res="${res//_/＿}"
	res="${res//\`/‵}"
	#res="${res//\//∕}"
	echo "$res"
}

while getopts "t:c:i:f:MHCrhlvjnRmDNT:" opt; do
	case $opt in
		t)
			TOKEN="$OPTARG"
			;;
		c)
			CHATS+=("$OPTARG")
			;;
		i)
			IMAGE_FILE="$OPTARG"
			;;
		f)
			DOCUMENT_FILE="$OPTARG"
			;;
		M)
			PARSE_MODE="Markdown"
			;;
		H)
			PARSE_MODE="HTML"
			;;
		C)
			PARSE_MODE="Markdown"
			CODE_MODE=1
			;;
		r)
			PARSE_MODE="Markdown"
			CRON_MODE=1
			;;
		l)
			ACTION="list_chats"
			;;
		v)
			DEBUG=true
			;;
		j)
			HAS_JQ=false
			;;
		n)
			DRY_RUN=true
			;;
		R)
			ACTION="receive_file"
			;;
		m)
			ACTION="receive_message"
			;;
		D)
			DISABLE_WEB_PAGE_PREVIEW=true
			;;
		N)
			DISABLE_NOTIFICATION=true
			;;
		T)
			TITLE="$OPTARG"
			;;
		?|h)
			help
			;;
		:)
			echo "Option -$OPTARG needs an argument."
			exit 1
			;;
		\?)
			echo "Invalid option -$OPTARG"
			exit 1
			;;
	esac
done

if [ "$CRON_MODE" -eq 1 ] && [ "$CODE_MODE" -eq 1 ]; then
	echo "You can either use -C or -r, but not both."
	exit 1
fi

log "TOKEN is now $TOKEN"
log "CHATS is now ${CHATS[*]}"

[ -z "$TOKEN" ] && TOKEN=$TELEGRAM_TOKEN
[ ${#CHATS[@]} -eq 0 ] && CHATS=($TELEGRAM_CHAT)

log "TOKEN is now $TOKEN"
log "CHATS is now ${CHATS[*]}"

log "Importing config file(s)..."

[ -r /etc/telegram.sh.conf ] && source /etc/telegram.sh.conf
[ -r ~/.telegram.sh ] && source ~/.telegram.sh
[ -r ~/.telegram.sh.conf ] && source ~/.telegram.sh.conf

[ -z "$TOKEN" ] && TOKEN=$TELEGRAM_TOKEN
[ ${#CHATS[@]} -eq 0 ] && CHATS=($TELEGRAM_CHAT)
[ -n "$TELEGRAM_DISABLE_WEB_PAGE_PREVIEW" ] && DISABLE_WEB_PAGE_PREVIEW="$TELEGRAM_DISABLE_WEB_PAGE_PREVIEW"
[ -n "$TELEGRAM_DISABLE_NOTIFICATION" ] && DISABLE_NOTIFICATION="$TELEGRAM_DISABLE_NOTIFICATION"

log "TOKEN is now $TOKEN"
log "CHATS is now ${CHATS[*]}"
log "DISABLE_WEB_PAGE_PREVIEW is now $DISABLE_WEB_PAGE_PREVIEW"
log "DISABLE_NOTIFICATION is now $DISABLE_NOTIFICATION"

if [ -z "$TOKEN" ]; then
	echo "No bot token was given."
	exit 1
fi

if [ ${#CHATS[@]} -eq 0 ] && [ -z "$ACTION" ]; then
	echo "No chat(s) given."
	exit 1
fi

if [ "$ACTION" = "list_chats" ]; then
	list_chats
	exit 0
fi

if [ "$ACTION" = "receive_file" ]; then
	receive_file
	exit 0
fi

if [ "$ACTION" = "receive_message" ]; then
	receive_message
	exit 0
fi

shift $((OPTIND - 1))
TEXT="$1"
log "Text: $TEXT"

[ "$TEXT" = "-" ] && TEXT=$(</dev/stdin)

log "Text: $TEXT"

if [ $CODE_MODE -eq 1 ]; then
	TEXT='```'$'\n'$TEXT$'\n''```'
fi

if [ $CRON_MODE -eq 1 ]; then
	ONLY_COMMANDS=1
	while read line; do
		if [ "${line:0:2}" = "+ " ]; then
			ONLY_COMMANDS=0
		fi
	done <<< "$TEXT"

	if [ "$ONLY_COMMANDS" -eq 1 ]; then
		exit 0
	fi

	TEXT='```'$'\n'$TEXT$'\n''```'

	#FIRST_LINE=1
	#BLOCK_OPEN=0
	#NEW_TEXT=""
	#while read line; do
	#	if [ "${line:0:2}" = "+ " ]; then
	#		if [ "$BLOCK_OPEN" -eq 1 ]; then
	#			NEW_TEXT="$NEW_TEXT"'```'$'\n'
	#			BLOCK_OPEN=0
	#		fi
	#		NEW_TEXT="$NEW_TEXT*`escapeMarkdown "${line:2}"`*"$'\n'
	#	else
	#		if [ "$BLOCK_OPEN" -eq 0 ]; then
	#			NEW_TEXT="$NEW_TEXT"'```'$'\n'
	#			BLOCK_OPEN=1
	#		fi
	#		NEW_TEXT="$NEW_TEXT$line"$'\n'
	#	fi
	#done <<< "$TEXT"
	#[ "$BLOCK_OPEN" -eq 1 ] && NEW_TEXT="$NEW_TEXT"'```'
	#TEXT="$NEW_TEXT"
fi

log "Text: $TEXT"

if [ -n "$TITLE" ]; then
	if [ "$PARSE_MODE" == "HTML" ]; then
		TEXT="<b>$TITLE</b>"$'\n\n'"$TEXT"
	elif [ "$PARSE_MODE" == "Markdown" ]; then
		TEXT="*$TITLE*"$'\n\n'"$TEXT"
	else
		TEXT="$TITLE"$'\n\n'"$TEXT"
	fi
fi

if [ -z "$TEXT" ] && [ -z "$DOCUMENT_FILE" ] && [ -z "$IMAGE_FILE" ]; then
	echo "Neither text nor image or other file given."
	exit 1
fi

if [ -n "$DOCUMENT_FILE" ] && [ -n "$IMAGE_FILE" ]; then
	echo "You can't send a file AND an image at the same time."
	exit 1
fi

[ -n "$PARSE_MODE" ] && CURL_OPTIONS="$CURL_OPTIONS --form-string parse_mode=$PARSE_MODE"
if [ -n "$DOCUMENT_FILE" ]; then
	check_file "$DOCUMENT_FILE"

	CURL_OPTIONS="$CURL_OPTIONS --form document=@\"$DOCUMENT_FILE\""
	CURL_OPTIONS="$CURL_OPTIONS --form caption=<-"
	METHOD="sendDocument"
elif [ -n "$IMAGE_FILE" ]; then
	check_file "$IMAGE_FILE"
	CURL_OPTIONS="$CURL_OPTIONS --form photo=@\"$IMAGE_FILE\""
	CURL_OPTIONS="$CURL_OPTIONS --form caption=<-"
	METHOD="sendPhoto"
else
	CURL_OPTIONS="$CURL_OPTIONS --form text=<-"
	[ "$DISABLE_WEB_PAGE_PREVIEW" = true ] && CURL_OPTIONS="$CURL_OPTIONS --form-string disable_web_page_preview=true"
	METHOD="sendMessage"
fi

[ "$DISABLE_NOTIFICATION" = true ] && CURL_OPTIONS="$CURL_OPTIONS --form-string disable_notification=true"

for id in "${CHATS[@]}"; do
	MY_CURL_OPTIONS="$CURL_OPTIONS --form-string chat_id=$id $URL$TOKEN/$METHOD"
	if [ "$DRY_RUN" = true ]; then
		echo "Executing: curl $MY_CURL_OPTIONS"
		echo "     Text: $TEXT"
		echo
		status=0
		response='{"ok": true}'
	else
		response=`curl $MY_CURL_OPTIONS <<< "$TEXT"`
		status=$?
	fi
	log "Response was: $response"
	if [ $status -ne 0 ]; then
		echo "curl reported an error. Exit code was: $status."
		echo "Response was: $response"
		echo "Quitting."
		exit $status
	fi

	if [ "$HAS_JQ" = true ]; then
		if [ "`jq -r '.ok' <<< "$response"`" != "true" ]; then
			echo "Telegram reported following error:"
			jq -r '"\(.error_code): \(.description)"' <<< "$response"
			echo "Quitting."
			exit 1
		fi
	else
		if [[ "$response" != '{"ok":true'* ]]; then
			echo "Telegram reported an error:"
			echo $response
			echo "Quitting."
			exit 1
		fi
	fi
done