introduce telegram-chatchange-90

Druvis from Mikrotik produced a video "MikroTik Telegram bot - Chat with
your Router?". He shows his script to chat with a Router via Telegram
bot to send it commands: https://youtu.be/KLX6j3sLRIE

This script is kind of limited and has several issues... 🥴

Let's make it robust, usable, multi-device capable and just fun! 😁

(Sadly Mikrotik has a policy to not allow links in Youtube comments.
Thus my comment with several hints was removed immediately. If anybody
is in contact with Druvis... Please tell him about this script!)

1 files changed, 89 insertions, 0 deletions

diff --git a/doc/telegram-chat.md b/doc/telegram-chat.md
new file mode 100644
index 0000000..b245efa
--- /dev/null
+++ b/doc/telegram-chat.md
@@ -0,0 +1,89 @@
+Chat with your router and send commands via Telegram bot
+========================================================
+
+[⬅️ Go back to main README](../README.md)
+
+> ℹ️ **Info**: This script can not be used on its own but requires the base
+> installation. See [main README](../README.md) for details.
+
+Description
+-----------
+
+This script makes your device poll a Telegram bot for new messages. With
+these messages you can send commands to your device and make it run them.
+The resulting output is send back to you.
+
+Requirements and installation
+-----------------------------
+
+Just install the script and the module for notifications via Telegram:
+
+    $ScriptInstallUpdate telegram-chat,mod/notification-telegram;
+
+Then create a schedule that runs the script periodically:
+
+    /system/scheduler/add start-time=startup interval=30s name=telegram-chat on-event="/system/script/run telegram-chat;";
+
+> ⚠️ **Warning**: Make sure to keep the interval in sync when installing
+> on several devices. Differing polling intervals will result in missed
+> messages.
+
+Configuration
+-------------
+
+Make sure to configure
+[notifications via telegram](mod/notification-telegram.md) first. The
+additional configuration goes to `global-config-overlay`, these are the
+parameters:
+
+* `TelegramChatIdsTrusted`: an array with trusted chat ids or user names
+* `TelegramChatGroups`: define the groups a device should belong to
+
+Usage and invocation
+--------------------
+
+This script is capable of chatting with multiple devices. By default a
+device is passive and not acting on messages. To activate it send a message
+containing `! identity` (exclamation mark, optional space and system's
+identity). To query all dynamic ip addresses form a device named "*MikroTik*"
+send `! MikroTik`, followed by `/ip/address/print where dynamic;`.
+
+![chat to specific device](telegram-chat.d/01-chat-specific.avif)
+
+Devices can be grouped to chat with them simultaneously. The default group
+"*all*" can be activated by sending `! @all`, which will make all devices
+act on your commands.
+
+![chat to all devices](telegram-chat.d/02-chat-all.avif)
+
+Send a single exclamation mark or non-existent identity to make all
+devices passive again.
+
+Known limitations
+-----------------
+
+### Do not use numeric ids!
+
+Numeric ids are valid within a session only. Usually you can use something
+like this to print all ip addresses and remove the first one:
+
+    /ip/address/print;
+    /ip/address/remove 0;
+
+This will fail when sent in separate messages. Instead you should use basic
+scripting capabilities. Try to print what you want to act on...
+
+    /ip/address/print where interface=eth;
+
+... verify and finally remove it.
+
+    /ip/address/remove [ find where interface=eth ];
+
+See also
+--------
+
+* [Send notifications via Telegram](mod/notification-telegram.md)
+
+---
+[⬅️ Go back to main README](../README.md)  
+[⬆️ Go back to top](#top)