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Best Practices
Customize commands.sh only
To ease Updates never change bashbot.sh, instead individual commands should go to commands.sh . Insert your Bot commands in the case ... esac block:
case "$MESSAGE" in
'/echo') # my first own command, echo MESSAGE
send_normal_message "${CHAT[ID]}" "${MESSAGE}"
;;
################################################
# DEFAULT commands start here, do not edit below this!
'/info')
bashbot_info "${CHAT[ID]}"
;;
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 a seperate file, e.g. mycommands.inc.sh and source it from bashbot.sh. Example:
source "mycommands.inc.sh"
case "$MESSAGE" in
'/process') # logic for /process is done in process_message
result="$(process_message "$MESSAGE")"
send_normal_message "${CHAT[ID]}" "$result"
;;
################################################
# DEFAULT commands start here, do not edit below this!
'/info')
bashbot_info "${CHAT[ID]}"
;;
'/start')
send_action "${CHAT[ID]}" "typing"
bashbot_help "${CHAT[ID]}"
;;
esac
#!/bin/bash
# file: mycommands.inc.sh
process_message() {
local ARGS="${1#/* }" # remove command
local TEXT OUTPUT=""
# process every word in MESSAGE, avoid globbing
set -f
for WORD in $ARGS
do
set +f
# process links
if [[ "$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} ${TEXT}"
TEXT=""
done
# return result, reset globbing in case we had no ARGS
set +f
echo "${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 :-)