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Best Practices
Add commands to mycommands.sh only
To ease updates never change bashbot.sh, instead your commands and functions must go to mycommands.sh . Insert your Bot commands in the case ... esac block of the 'mycommands()' function:
# file: mycommands.sh
# your additional bahsbot commands
# uncomment the following lines to overwrite info and help messages
bashbot_info='This is *MY* variant of _bashbot_, the Telegram bot written entirely in bash.
'
bashbot_help='*Available commands*:
/echo message - _echo the given messsage_
'
mycommands() {
case "$MESSAGE" in
'/echo'*) # example echo command
send_normal_message "${CHAT[ID]}" "$MESSAGE"
;;
# .....
esac
}
Reuse or disable standard commands
If you want to disable or reuse a standard bashbot command comment it out in 'commands.sh' by placing a '#' in front of
every line from '/command') to ;;.
Note: Never disable the catchall command *) in 'commands.sh'!!
# file: commands.sh
case "$MESSAGE" in
################################################
# DEFAULT commands start here, edit messages only
#'/start')
# send_action "${CHAT[ID]}" "typing"
# _is_botadmin && _markdown_message "You are *BOTADMIN*."
# if _is_allowed "start" ; then
# _markdown_message "${bot_help}"
# else
# _message "You are not allowed to start Bot."
# fi
# ;;
*) # forward other messages to optional dispatcher
_is_function startproc && if tmux ls | grep -v send | grep -q "$copname"; then inproc; fi # interactive running
_is_function mycommands && mycommands
;;
esac
Seperate logic from commands
If a command need more than 2-3 lines of code, you should use a function to seperate logic from command. Place your functions in mycommands.sh and call the from your command. Example:
# file: mycommands.sh
# your additional bahsbot commands
mycommands() {
case "$MESSAGE" in
'/process') # logic for /process is done in process_message
result="$(process_message "$MESSAGE")"
send_normal_message "${CHAT[ID]}" "$result"
;;
esac
}
# place your functions here
process_message() {
local ARGS="${1#/* }" # remove command
local TEXT OUTPUT=""
# process every word in MESSAGE, avoid globbing
set -f
for WORD in $ARGS
do
# process links
if [[ "$WORD" == "https://"* ]]; then
REPORT="$(dosomething_with_link "$WORD")"
# no link, add as text
else
TEXT="$(echo "${TEXT} $WORD")"
continue
fi
# compose result
OUTPUT="* ${REPORT} ${WORD} ${TEXT}"
TEXT=""
done
# return result, reset globbing in case we had no ARGS
echo "${OUTPUT}${TEXT}"
}
Test your Bot with shellcheck
Shellcheck is a static linter for shell scripts providing excellent tips and hints for shell coding pittfalls. You can use it online or install it on your system. All bashbot scripts are linted by shellcheck.
Shellcheck examples:
$ shellcheck -x mybotcommands.inc.sh
Line 17:
TEXT="$(echo "${TEXT} $WORD")"
^-- SC2116: Useless echo? Instead of 'cmd $(echo foo)', just use 'cmd foo'.
As you can see my mybotcommands.inc.sh contains an useless echo command in 'TEXT=' assigment and can be replaced by TEXT="${TEXT}${WORD}"
$ shellcheck -x examples/notify
OK
$ shellcheck -x examples/question
OK
$ shellcheck -x commands.sh
OK
$ shellcheck -x bashbot.sh
In bashbot.sh line 123:
text="$(echo "$text" | sed 's/ mynewlinestartshere /\r\n/g')" # hack for linebreaks in startproc scripts
^-- SC2001: See if you can use ${variable//search/replace} instead.
In bashbot.sh line 490:
CONTACT[USER_ID]="$(sed -n -e '/\["result",'$PROCESS_NUMBER',"message","contact","user_id"\]/ s/.*\][ \t]"\(.*\)"$/\1/p' <"$TMP")"
^-- SC2034: CONTACT appears unused. Verify it or export it.
The example show two warnings in bashbots scripts. The first is a hint you may use shell substitions instead of sed, this is fixed and much faster as the "echo | sed" solution. The second warning is about an unused variable, this is true because in our examples CONTACT is not used but assigned in case you want to use it :-)