telegram-bot-bash/doc/4_expert.md

Expert Use

Handling UTF-8 character sets

UTF-8 is a variable length encoding of Unicode. UTF-8 is recommended as the default encoding in JSON, XML and HTML, also Telegram make use of it.

The first 128 characters are regular ASCII, so it's a superset of and compatible with ASCII environments. The next 1,920 characters need two bytes for encoding and covers almost all Latin alphabets, also Greek, Cyrillic, Hebrew, Arabic and more. See Wikipedia for more deatils.

Setting up your Environment

In general bash and GNU utitities are UTF-8 aware, but you have to setup your environment and your scripts accordingly:

1. Your Terminal and Editor must support UTF-8: Set Terminal and Editor locale to UTF-8, eg. in Settings/Configuration select UTF-8 (Unicode) as Charset.

2. Set Shell environment to UTF-8 in your .profile and your scripts. The usual settings are:

export 'LC_ALL=C.UTF-8'
export 'LANG=C.UTF-8'
export 'LANGUAGE=C.UTF-8'

If you use other languages, eg. german or US english, change the shell settings to:

export 'LC_ALL=de_DE.UTF-8'
export 'LANG=de_DE.UTF-8'
export 'LANGUAGE=de_DE.UTF-8'

export 'LC_ALL=en_US.UTF-8'
export 'LANG=de_en_US.UTF-8'
export 'LANGUAGE=den_US.UTF-8'

3. make shure your bot scripts use the correct settings, eg. include the lines above at the beginning of your scripts

To display all availible locales on your system run locale -a | more. Gentoo Wiki

UTF-8 Support

Telegram send JSON messages with all characters not fitting in one byte (<256 bit) escaped as sequences of \uxxxx to be regular one byte ASCII. Multibyte UTF-8 characters, e.g. Emoticons and Arabic characters, are send in UTF-16 notation. The Emoticons 😁 😘 ❤️ 😊 👍 are encoded as: \uD83D\uDE01 \uD83D\uDE18 \u2764\uFE0F \uD83D\uDE0A \uD83D\uDC4D

This mixed JSON encoding can not decoded from echo -e or printf '%s\\n', this works only for single byte characters!

To to fully support decoding of multibyte characters you need a working python2 installation on your system. If no python is detected bashbot falls back to a slow, pure bash solution which may not work for some corner cases.

Run as other user or system service

Bashbot is desingned to run manually by the user who installed it. Nevertheless it's possible to run it by an other user-ID, as a system service or sceduled from cron. This is onyl recommended for experiend linux users.

Running bashbot as an other user is only possible with sudo rigths.

Setup the environment for the user you want to run bashbot and enter desired username, e.g. nobody :

sudo ./bashbot.sh init

Edit the file bashbot.rc and edit the following lines to fit your configuration:

#######################
# Configuration Section

# edit the next line to fit the user you want to run bashbot, e.g. nobody:
runas="nobody" 

# uncomment one of the following lines 
# runcmd="su $runas -s /bin/bash -c "      # runasuser with su
# runcmd="runuser $runas -s /bin/bash -c " # runasuser with runuser

# edit the values of the following lines to fit your config:
start="/usr/local/telegram-bot-bash/bashbot.sh"	# location of your bashbot.sh script
name=''   # your bot name as given to botfather, e.g. mysomething_bot

# END Configuration
#######################

From now on always use bashbot.rc to start/stop your bot:

sudo ./bashbot.rc start

Type ps -ef | grep bashbot to verify your Bot is running as the desired user.

If you started bashbot by bashbot.rc you must use bashbot.rc also to manage your Bot! The following commands are availible:

sudo ./bashbot.rc start
sudo ./bashbot.rc stop
sudo ./bashbot.rc status
sudo ./bashbot.rc suspendback
sudo ./bashbot.rc resumeback
sudo ./bashbot.rc killback

To change back the environment to your user-ID run sudo ./bashbot.sh init again and enter your user name.

To use bashbot as a system servive include a working bashbot.rc in your init system (systemd, /etc/init.d).

Scedule bashbot from Cron

An example crontab is provided in bashbot.cron.

• If you are running bashbot with your user-ID, copy the examples lines to your crontab and remove username nobody.
• if you run bashbot as an other user or a system service edit bashbot.cron to fit your needs and replace usernamenobody with the username you want to run bashbot. copy the modified file to /etc/cron.d/bashbot

$$VERSION$$ v0.6-rc1-11-gba80ec6