Telegrtam-cli and i3

telegram-cli-i3.md

Telegram-cli Notifications for i3wm

My first experience with a Linux desktop environment was gnome. It was fine, I guess, but I spent most of my time in the terminal so I never really learned where anythign was or how to do anything using gnome. I just had it.
Later on I got introduced to i3wm(i3 for short). Love at first sight.
I use vim, I use tmux, you'd think I already had enough tabs, panes, windows, sessions. You'd be most certainly wrong. After i3 I realised I still needed more.
I use telegram because friends, family, life.
It's annoying to have to pay attention to my cellphone(I know I'm a horrible person, no need to point that out). Having i3 notifications is just more convinient.
So the next obvious step was to get just that. Telegram-cli has both Python and Lua APIs. I used the Lua API. I have no reason whatsoever to back my decision up other than I just felt like doing it in Lua.
TL;DR.
A Telegram-cli Lua script has to implement a couple of hook functions(the API gives us hooks and callbacks).

• on_binlog_replay_end(ok_cb, extra) this one runs when replay of old events has finished.
  
• on_get_difference_end(ok_cb, extra) runs after the first call to get_difference.
  
• on_our_id(our_id) using this, you can check the id of the user you are logged in as.
  
• on_msg_receive(msg) it's called when we receive a new message.
  
• on_user_update(user, what_changed) is called when there is an update on the user's info.
  
• on_chat_update(user, what_changed) is called when there is an update on a chat info.
  
• on_secret_chat_update(user, what_changed) is called when there is updated info for a secret chat.
  

You can read the Lua API documentation here. The documentation could use some help. If you can't find anything there, either look at the source code for the Lua API here or just look at the Python API doc here.
We are only going to implement on_binlog_replay_end and on_msg_receive.
Implementing those two hooks would give us a way to know when we receive a new maessage and if for whatever reason we missed that, how many unread messages we have.
The version of the script I use presonally, sends notifications to a server. Then, a client can query the server for updates. The client is what i3 calls for a block update(I use i3-blocks).
Also note that telegram-cli will output a lot of things to stdout, so we can't just have our Lua script dump info to stdout and then use telegram-cli -s myscript.lua for i3.
You could run telegram-cli in daemon mode and achieve the same thing without a server-client set-up, then register our hook functions as telegram-cli commands and then use netcat to have our custom command executed by the daemon(the command registered with i3 would be the netcat command). For more on that you can look here.
How you use this is up to you and I'll leave that part to you. We'll just cover the hook functions.
For on_msg_receive we have:

function on_msg_receive(msg)
  if (msg.from.print_name == "JohnDoe") then
    return
  end
  local socket = require("socket")
  local host, port = "localhost", 11111
  local tcp = assert(socket.tcp())
  tcp:connect(host, port)
  print(msg.from.print_name)
  tcp:send("JohnDoe".."\n")
  tcp:close()
end

The function above will only notify us if our contact JohnDoe has sent us a message. If you want to be notified of all new messages, you can just get rid of the if.

To get the unread messages we do:

function ok_cb(extra, success, result)
  for k, v in pairs(result) do
    if v["unread"] ~= 0. then
      if v["peer"]["username"] == "johndoe82" then
        local socket = require("socket")
        local host, port = "localhost", 11111
        local tcp = assert(socket.tcp())
        tcp:connect(host, port)
        tcp:send("JohnDoe".."\n")
        tcp:close()
      end
    end
  end
end

function on_binlog_replay_end()
  get_dialog_list(ok_cb, result)
end

For the daemon+netcat variation, you can put the call to dialog_list inside a new function and register that as a telegram-cli command and run that command with netcat.
The last thing is, if you don't want to have telegram-cli runnning all the time, daemon or not, you can call safe_quit() in your Lua script to quit telegram-cli.