We’ll cover a simple example of sending a slack message every morning to get the day weather’s forecast: min-max temp and an emoji depicting what the sky will be like, using OpenWeatherMap free API.

🌡️➡️📲

todo todo

Intro

The goal is to create an automated bot that sends weather information every morning on a slack channel with 0 code (or maybe a maximum of 2 lines). To do so, we’re going to use Node-RED, an automation tool based on a visual interface to query APIs and trigger external tools. See it like a free, highly customizable and self-hosted IFTTT. Each action is a Node and is connected to another ones/ones with wires.

Install and run

Node red install doc

$ node -v # >=  8.x
$ sudo npm install -g --unsafe-perm node-red # install node red globally
$ node-red # will create a ~/.node-red folder to store config & data

Welcome to Node-RED
===================
22 Nov 21:53:17 - [info] Node-RED version: v0.19.5
22 Nov 21:53:17 - [info] Node.js  version: v8.12.0
22 Nov 21:53:23 - [info] User directory : /home/florian/.node-red
22 Nov 21:53:23 - [info] Server now running at http://127.0.0.1:1880/

Go ahead and open http://127.0.0.1:1880/, you’ll have an empty flow open by default: todo

Discover

Drag n drop an inject, a debug, connect them together, hit Deploy, click on the blue square on the left of the inject node and open the debug console: todo

This is the very first step! This is what happened:

  • inject creates a global Javascrippt object msg with the key payload containing the actual int timestamp
  • inject sends it to the Debug
  • debug displays in the console the default configured output msg.payload

Double-clicking on the Debug node displays the configuration: todo

Build the weather bot

Connect to Open Weather Map

Create API key on Open Weather Map and use it in the following endpoint:

https://api.openweathermap.org/data/2.5/weather?q=Paris,fr&appid=[APP_ID]&units=metric

Default call for testing https://samples.openweathermap.org/data/2.5/weather?q=London,uk&appid=b6907d289e10d714a6e88b30761fae22

Look for the node http request, set the endpoint and change the return to be a JSON object: todo

Deploy and run! todo

And it took what, 5 min? Sweeet…

Format

Use the template node a little bit of moustache templating and here we are:

{ {payload.main.temp_min}}/{ {payload.main.temp_max}}

todo todo

Send to Slack

Install the Node red slack module

npm install node-red-contrib-slack

Make sure you have a webhook configured on your slack, i.e. https://my_instance.slack.com/apps/manage/custom-integrations: todo

And use the slack node with the correct Webhook URL: todo

CRON it with Node RED

Think of using it on a daily basis? Node RED has a much easier system than Linux’s CRONs.

Open up the inject node and define the Regular setting. todo

Conclusion

You now have a fully working bot sending weather information every morning! Going further: display an emoji based on payload.weather[0].id (see https://openweathermap.org/weather-conditions), connect to your home IoT, your smart mirror…