In one of my last blog posts I set up WeeChat in docker, which works mostly pretty great for me so far. Although, it started to bug me that I felt the need to regularly check IRC in case I missed someone potentially tagging or private-messaging me. While looking around at how I could be notified on mentions and private messages, I found the trigger plugin. A powerful plugin that comes pre-installed on WeeChat. It lets the user specify a WeeChat command that will be executed when a specific event occurs. This plugin is probably powerful enough to build a small IRC bot, directly in WeeChat.

Also, I recently found the web service ntfy.sh. It sends push notifications whenever you send an HTTP post request to a certain URL. I already have ntfy.sh installed on my android phone, and I also found a minimal and lightweight desktop client.

I managed to set a WeeChat trigger up that fires every time I get mentioned (highlighted in WeeChat terminology), and a trigger that fires every time I get a private message. Both of those triggers execute the /exec command which runs an arbitrary shell command. The exec command runs the wget program to send a post request to the ntfy.sh server, which in turn sends a notification to all apps that subscribe to the same URL as the post request was sent. I would usually use the curl program for this instead of wget, but the docker default docker image doesn't contain a curl install.

Here you can see the two /trigger commands:

trigger on mention

/trigger addreplace notify_highlight print '' '${tg_highlight}' '/.*/${weechat.look.nick_prefix}${tg_prefix_nocolor}${weechat.look.nick_suffix} ${tg_message_nocolor}/' '/exec -norc -nosw -bg wget -O- --post-data "${tg_message}" "-                   -header=Title: New highlight: ${buffer.full_name}" https://ntfy.sh/my_ntfy_topic_1234'

trigger on private message

/trigger addreplace notify_privmsg print '' '${tg_tag_notify} == private && ${buffer.notify} > 0' '/.*/${weechat.look.nick_prefix}${tg_prefix_nocolor}${weechat.look.nick_suffix} ${tg_message_nocolor}/' '/exec -norc -nosw -bg wget -O- --post-data "${tg_message}" "--header=Title: New private message: ${buffer.full_name}" https://ntfy.sh/my_ntfy_topic_1234'

The trigger commands in detail

In case you don't just want to copy and paste some random command from the internet into your WeeChat (which you shouldn't do anyway), I will try to explain the trigger command that fires when you get mentioned in a message:

Let's first look at the trigger command itself: /trigger addreplace <name> <hook> <argument> <condition> <variable-replace> <command> We call the /trigger command with the addreplace subcommand. This subcommand will either register a new trigger or replace it if one with the same name already exists.

name - This argument is self-explanatory, the name of the trigger. In our case I called it notify_highlight, but you could call it whatever you want.
hook - This argument specifies which hook or event the trigger should listen for. WeeChat is built as an event-driven platform, so pretty much anything from mouse movements to IRC messages are handled via events. In this case, we want to trigger on the print event, which is fired every time a new message gets received from IRC.
argument - The argument is needed for some hooks, but not for the print hook, so we are going to ignore that one for now and just set it to an empty string ''.
condition - The condition must evaluate to true for the trigger to fire. This is helpful because the print trigger fires for every new message, but we only want to be notified when the new message mentions our nick. The condition for this is ${tg_highlight}. You can find the list of variables that you can access with the command /trigger monitor, which prints all variables for every trigger that gets executed.
variable-replace - This took me a while to understand. This command is used to manipulate data and save it to a variable. The syntax is inspired by the sed command. Explaining it fully is out of the scope of this blog post, but you can take a look at the docs. In our example, we replace the whole content of the variable tg_message with the format string ${weechat.look.nick_prefix}${tg_prefix_nocolor}${weechat.look.nick_suffix} ${tg_message_nocolor} which results in a sting like <tiim> Hello world!.
command - The last argument is the command that gets executed whenever this trigger fires. In our case, we use the /execute command, which starts the wget command which in turn sends a post request to ntfy.sh. Make sure you set the ntfy topic (the part after https://ntfy.sh/) to something private and long enough so that nobody else is going to guess it by accident.

Don't forget to subscribe to the ntfy topic on your phone or whatever device you want to receive the notification on.

The possibilities with the trigger plugin are endless, I hope this inspires you to build your own customizations using weechat.

🏷️ Tag: wget

Weechat Notifications with ntfy.sh