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

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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 details.

Setting up your Environment

In general bash and GNU utitities are UTF-8 aware if you 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

Bashbot UTF-8 Support

Bashbot handles all messages transparently, regardless of the charset in use. The only exception is when converting from JSON data to strings.

Telegram use JSON to send / recieve data. JSON encodes strings as follow: Characters not ASCII (>127) are escaped as sequences of \uxxxx to be regular ASCII. In addition multibyte characters, e.g. Emoticons or Arabic characters, are send in double byte UTF-16 notation. The Emoticons 😁 😘 ❤️ 😊 👍 are encoded as: \uD83D\uDE01 \uD83D\uDE18 \u2764\uFE0F \uD83D\uDE0A \uD83D\uDC4D

This "mixed" JSON encoding needs special handling and can not decoded from echo -e or printf '%s\\n'

Most complete support for decoding of multibyte characters can only be provided if python is installed on your system. Without phyton bashbot falls back to an internal, pure bash implementation 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.

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 use 'bashbot.rc' to manage your bot:

sudo ./bashbot.rc start

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

If your Bot is started 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 examples/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 examples/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

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