telegram-bot-bash/README.txt

<h2><img align="middle" 
src="https://raw.githubusercontent.com/odb/official-bash-logo/master/assets/Logo
s/Icons/PNG/64x64.png" >
Bashbot - A Telegram bot written in bash.
</h2>
Written by Drew (@topkecleon), Daniil Gentili (@danogentili), and Kay M 
(@gnadelwartz).

Contributions by JuanPotato, BigNerd95, TiagoDanin, and iicc1.

Released to the public domain wherever applicable.
Elsewhere, consider it released under the 
[WTFPLv2](http://www.wtfpl.net/txt/copying/).

## Prerequisites
Uses [JSON.sh](http://github.com/dominictarr/JSON.sh), but no more TMUX.

Even bashbot is written in bash, it depends on commands typically availible in 
a Unix/Linux Environment.
More concret on the common commands provided by recent versions of 
[coreutils](https://en.wikipedia.org/wiki/List_of_GNU_Core_Utilities_commands), 
[busybox](https://en.wikipedia.org/wiki/BusyBox#Commands) or 
[toybox](https://landley.net/toybox/help.html), see [Developer 
Notes](doc/7_develop.md#common-commands)

*Note for MacOS and BSD Users:* As bashbot heavily uses modern bash and (gnu) 
grep/sed features, bashbot will not run without installing additional software, 
see [Install Bashbot](doc/0_install.md)


Bashbot [Documentation](https://github.com/topkecleon/telegram-bot-bash) and 
[Downloads](https://github.com/topkecleon/telegram-bot-bash/releases) are 
availible on www.github.com

## Documentation
* [Introdution to Telegram Bots](https://core.telegram.org/bots)
* [Install Bashbot](doc/0_install.md)
    * Install release
    * Install from githup
    * Update Bashbot
    * Notes on Updates
* [Get Bottoken from Botfather](doc/1_firstbot.md)
* [Getting Started](doc/2_usage.md)
    * Managing your Bot
    * Recieve data
    * Send messages
    * Send files, locations, keyboards
* [Advanced Features](doc/3_advanced.md)
    * Access Control
    * Interactive Chats
    * Background Jobs
    * Inline queries
    * Send message errors
* [Expert Use](doc/4_expert.md)
    * Handling UTF-8 character sets
    * Run as other user or system service
    * Scedule bashbot from Cron
    * Use from CLI and Scripts
    * Customize Bashbot Environment
* [Best Practices](doc/5_practice.md)
    * Customize mycommands.sh
    * Overwrite/disable commands
    * Seperate logic from commands
    * Test your Bot with shellcheck
* [Function Reference](doc/6_reference.md)
    * Sending Messages, Files, Keyboards
    * User Access Control
    * Inline Queries
    * jsshDB Bashbot key-value storage
    * Background and Interactive Jobs
* [Deveoper Notes](doc/7_develop.md)
    * Debug bashbot
    * Modules, addons, events
    * Setup your environment
    * Bashbot testsuite
* [Examples Dir](examples/README.md)

### Your really first bashbot in a nutshell

To install and run bashbot you need acess to a linux/unix command line. If you 
don't know how to get accces to a linux/unix/bsd like command line you should 
stop reading here :-(

In addition you need a [Telegram client](https://telegram.org) and a mobile 
phone to [register an 
account](https://telegramguide.com/create-a-telegram-account/).
If you don't want to register for Telegram you should stop reading here ;-)

After you're registered to Telegram send a message to 
[@botfather](https://telegram.me/botfather),
[create a new Telegram Bot token](doc/1_firstbot.md) and write it down. You 
need the token to install the bot.

Now open a linux/unix/bsd terminal and check if bash is installed: ```which 
bash && echo "bash installed!"```.
If you get an error message bash is not installed.

Create a new directory and change to it:  ```mkdir tbb; cd tbb``` and download 
the latest '*.tar.gz' file from
[https://github.com/topkecleon/telegram-bot-bash/releases](https://github.com/to
pkecleon/telegram-bot-bash/releases). This can be done with the commands:
```bash
wget -q https://github.com/$(wget -q 
https://github.com/topkecleon/telegram-bot-bash/releases/latest -O - | egrep 
'/.*/.*/.*tar.gz' -o)
```

Extract the '*.tar.gz' file and change to bashbot directory: ```tar -xzf 
*.tar.gz; cd telegram-bot-bash```,
install bashbot: ```./bashbot.sh init``` and enter your bot token when asked. 
All other questions can be answered
by hitting the \<Return\> key.

Thats all, now you can start your bot with ```./bashbot.sh start``` and send 
him messages:
```
/start

You are Botadmin
*Available commands*:
*• /start*: _Start bot and get this message_.
*• /help*: _Get this message_.
*• /info*: _Get shorter info message about this bot_....

/info

his is bashbot, the Telegram bot written entirely in bash.
It features background tasks and interactive chats, and can serve as an 
interface for CLI programs.
```
For more Information on how to install, customize and use your new bot, read 
the [Documentation](#Documentation)

### Log files

Since version 0.96 bashbot log commands recieved (updates) and connection 
errors. If you start bashbot in debug mode
bash stdout, stderr and all recieved telegram message updates are logged also.

To enable debug mode start bashbot with debug as third argument: `bashbot start 
debug`

```
├── logs 
│   ├── ERROR.log        # connection errors from / to telegram API
│   ├── UPDATE.log       # summary whats received from your bot
│   │
│   ├── DEBUG.log        # stdout/stderr of you bot (debug mode enabled)
│   └── MESSAGE.log      # full text of all message updates received (debug 
mode enabled)
```

----

## Security Considerations
Running a Telegram Bot means it is connected to the public and you never know 
whats send to your Bot.

Bash scripts in general are not designed to be bullet proof, so consider this 
Bot as a proof of concept. Bash programmers often struggle with 'quoting hell' 
and globbing, see [Implications of wrong 
quoting](https://unix.stackexchange.com/questions/171346/security-implications-o
f-forgetting-to-quote-a-variable-in-bash-posix-shells)

Whenever you are processing input from from untrusted sources (messages, files, 
network) you must be as carefull as possible, e.g. set IFS appropriate, disable 
globbing (set -f) and quote everthing. In addition delete unused scripts and 
examples from your Bot, e.g. scripts 'notify', 'calc', 'question', and disable 
all not used commands.

**Note:** Until v0.941 (mai/22/2020) telegram-bot-bash had a remote code 
execution (RCE) bug, pls update if you use an older version!
see [Issue #125](https://github.com/topkecleon/telegram-bot-bash/issues/125)

One of the most powerful features of unix shells like bash is variable and 
command substitution using ```${}``` and ```$()```,
but as they are expanded in doble quotes, this can lead to RCE and information 
disclosing bugs in complex scripts like bashbot
even bash does much to avoid this. So it's more secure to escape or remove '$' 
in input from user, files or network.

A powerful tool to improve your scripts is ```shellcheck```. You can [use it 
online](https://www.shellcheck.net/) or [install shellcheck 
locally](https://github.com/koalaman/shellcheck#installing). Shellcheck is used 
extensive in bashbot development to enshure a high code quality, e.g. it's not 
allowed to push changes without passing all shellcheck tests.
In addition bashbot has a [test suite](doc/7_develop.md) to check if important 
functionality is working as expected.

### use printf whenever possible

If you're writing a script and it is taking external input (from the user as 
arguments, or file names from the file system...),
you shouldn't use echo to display it. [Use printf whenever 
possible](https://unix.stackexchange.com/a/6581)

```bash
  # very simple
  echo "text with variables. PWD=$PWD"
  printf '%s\n' "text with variables. PWD=$PWD"
  -> text with variables. PWD=/home/xxx

  # more advanced
  FLOAT="1.2346777892864" INTEGER="12345.123"
  echo "text with variabeles. float=$FLOAT, integer=$INTEGER, PWD=$PWD"
  ->text with variables. float=1.2346777892864, integer=12345.123, PWD=/home/xxx

  printf "text with variables. float=%.2f, integer=%d, PWD=%s\n" "" "$INTEGER" 
"$PWD"
  ->text with variables. float=1.23, integer=12345, PWD=/home/xxx
```

### Do not use #!/usr/bin/env bash

**We stay with /bin/bash shebang, because it's more save from security 
perspective.**

Using a fixed path to the system provided bash makes it harder for attackers or 
users to place alternative versions of bash
and avoids using a possibly broken, mangled or compromised bash executable. 

If you are a BSD /  MacOS user or must to use an other bash location, see 
[Install Bashbot](doc/0_install.md)

### Run your Bot as a restricted user
**I recommend to run your bot as a user, with almost no access rights.** 
All files your Bot have write access to are in danger to be overwritten/deleted 
if your bot is hacked.
For the same reason ervery file your Bot can read is in danger to be disclosed. 
Restict your Bots access rigths to the absolute minimum.

**Never run your Bot as root, this is the most dangerous you can do!** Usually 
the user 'nobody' has almost no rights on Unix/Linux systems. See [Expert 
use](doc/4_expert.md) on how to run your Bot as an other user.

### Secure your Bot installation
**Your Bot configuration must no be readable from other users.** Everyone who 
can read your Bots token can act as your Bot and has access to all chats your 
Bot is in!

Everyone with read access to your Bot files can extract your Bots data. 
Especially your Bot Token in ```token``` must be protected against other users. 
No one exept you must have write access to the Bot files. The Bot must be 
restricted to have write access to ```count``` and  ```tmp-bot-bash``` only, 
all other files must be write protected.

To set access rights for your bashbot installation to a reasonable default run 
```sudo ./bashbot.sh init``` after every update or change to your installation 
directory.

## FAQ

### Is this Bot insecure?
Bashbot is not more (in)secure as any other Bot written in any other language, 
we have done our best to make it as secure as possible. But YOU are responsible 
for the bot commands you wrote and you should know about the risks ...

**Note:** Until v0.941 (mai/22/2020) telegram-bot-bash has a remote code 
execution bug, pls update if you use an older version!

### Why Bash and not the much better xyz?
Well, thats a damn good question ... may be because I'm an Unix/Linux admin 
from stone age. Nevertheless there are more reasons from my side:

- bashbot will run everywhere where bash is availible, from ebedded linux to 
mainframe
- easy to integrate with other shell script, e.g. for sending system message / 
health status
- no need to install or learn a new programming language, library or framework
- no database, not event driven, not OO ...

### Can I have the single bashbot.sh file back?
At the beginning bashbot was simply the file ```bashbot.sh``` you can copy 
everywhere and run the bot. Now we have 'commands.sh', 'mycommands.sh', 
'modules/*.sh' and much more.

Hey no Problem, if you are finished with your cool bot run 
```dev/make-standalone.sh``` to create a stripped down Version of your bot 
containing only
'bashbot.sh' and 'commands.sh'! For more information see [Create a stripped 
down Version of your Bot](doc/7_develop.md)

### Can I send messages from CLI and scripts?
Of course, you can send messages from CLI and scripts, simply install bashbot 
as [described here](#Your-really-first-bashbot-in-a-nutshell),
send the messsage '/start' to set yourself as botadmin and stop the bot with 
```./bashbot.sh kill```.

Run the following commands in your bash shell or script while you are in the 
installation directory:

```bash
# prepare bash / script to send commands
export BASHBOT_HOME="$(pwd)"
source ./bashbot.sh source

# send me a test message
send_message "$(cat "$BOTADMIN")" "test"

# send me output of a system command
send_message "$(<"$BOTADMIN")" "$(df -h)"
```
For more information see [Expert Use](doc/8_custom.md)


### Why do I get "EXPECTED value GOT EOF" on start?
May be your IP is blocked by telegram. You can test this by running curl or 
wget manually:
```bash
curl -m 10  https://api.telegram.org/bot
#curl: (28) Connection timed out after 10001 milliseconds

wget -t 1 -T 10 https://api.telegram.org/bot
#Connecting to api.telegram.org (api.telegram.org)|46.38.243.234|:443... 
failed: Connection timed out.
```
This may happen if to many wrong requests are sent to api.telegram.org, e.g. 
using a wrong token or not existing API calls.  If you have a fixed IP you can 
ask telegram service to unblock your ip or change your IP. If you are running a 
socks or  tor proxy on your server look for the ```BASHBOT_CURL_ARGS``` lines 
in 'mycommands.sh' as example.


@Gnadelwartz

## That's it!

If you feel that there's something missing or if you found a bug, feel free to 
submit a pull request!

#### $$VERSION$$ v0.98-dev-42-geea1de6