Getting a Slack helper running with Netlify: Part 1

This post was written as a "Live blog". I.e. I was updating as I went. There may be typos & coding errors, but the timestamps at the top of each section should help

So I'm a bit of a dinosaur when it comes to web stacks - I'm all about LAMP (Linux, Apache, MySQL, PHP). I had an idea for a small little web app and thought it would be the perfect opportunity to give Netlify a go.

I've not really used Netlify before (I have a single app running with a useful function for some behind-the-scenes stuff for me) but that was cobbled together with me copying and pasting commands.

With that knowledge and some Slack API knowledge I'm going to see how quickly I can get a proof of concept together. It will all be written in JavaScript using their functions

Brief: Have a web app feature 4 buttons. Each button will update my work Slack status with a predefined status. This means I can quickly open it on my phone and hit a button rather than going through the Slack UI and writing it every time.

The name will be sitrep.

The app will also show the current status and when it expires (if it does).

7:43pm

I've signed up for Netlify and globally installed the netlify cli (npm install netlify-cli -g). I've also created a folder (good start) and made an empty git repo (git init).

I don't want to use auto deployments from Gitlab/Gitlab (because...reasons), so going to do a netlify init in my folder.

7:49pm

I've created a netlify.toml file so I can specify my site root and where the functions are going to live - the contents is just the following. I've made the folders.

[build]
  publish = "html/"
  functions = "functions/"

You can then run netlify dev to give you a server to serve your files. As the actual "website" is going to be static HTML I don't need to run any build tools. Just need to figure out how I can trigger a function call locally...

7:55pm

OK, so with netlify dev running, the URLs are the same as they would be on live. So I have made a file (functions/sitrep.js) which can then be called from http://localhost:8888/.netlify/functions/sitrep

This is because in the netlify.toml file, I told it where the functions lived. The contents of this file needs to look something like:

exports.handler = function(event, context, callback) {
	return {
		statusCode: 200,
		body: 'POW'
	};
};

Inside the event variable is all the good stuff you might need (and I might need to make this web app sound). Things like httpMethod, client-ip etc.

Next step, getting on with the Slack API

Custom status is part of a user's profile and setting status requires the users.profile:write scope.

8:13pm

So you need to make an App in Slack to get the right API details. It's a faff and I don't really have a link to share as it is tied to my workspace. However, somehow, I made an app.

Once you have that app you can give it permissions - there are two in particular we need

  • users.profile:read - for reading the status
  • users.profile:write - for writing the status

Once you have that (and installed your app on your workspace) you then get a OAuth Access Token which you can use.

8:19pm

Turns out you can't use fetch natively in Netlify functions. So I moved my js file into a folder of the same name - this way you can create a package.json file associated with that function.

I then cd'd into that directory and ran

npm init && npm i node-fetch --save

My folder structure is now

  • functions/
  • sitrep/
    • sitrep.js
    • package.json

In the functions file I can call const fetch = require('node-fetch'); and get access to fetch

8:32pm

Managed to get and update my user status using a function. Took some tomfoolery, but thanks to this repo I was able to get it working:

Reading a status

return fetch('https://slack.com/api/users.profile.get', {
	headers: {
		'content-type': 'application/json; charset=utf-8',
		'authorization': 'Bearer xoxp-XXXXXXX'
	},
	method: 'GET'
})
	.then(data => data.json())
	.then((data) => ({
		statusCode: 200,
		body: JSON.stringify(data)
	}))
	.catch(error => ({
		statusCode: 422,
		body: `Oops! Something went wrong. ${error}`
	}));

Updating a status

return fetch('https://slack.com/api/users.profile.set', {
	headers: {
		'content-type': 'application/json; charset=utf-8',
		'authorization': 'Bearer xoxp-XXXXX'
	},
	method: 'POST',
	body: JSON.stringify({
		'profile': {
			'status_text': 'riding a train',
			'status_emoji': '๐Ÿšž',
			'status_expiration': 0
		}
	})
})
	.then(data => data.json())
	.then((data) => ({
		statusCode: 200,
		body: JSON.stringify(data)
	}))
	.catch(error => ({
		statusCode: 422,
		body: `Oops! Something went wrong. ${error}`
	}));

This then gives you the whole profile back but the status is in there ๐Ÿ‘.

Now I need to tidy up the code and add some if/switch statements. I'll use GET parameters for now, but might move to POST later.

8:54pm

Top tip (took me a few mins to realise) - If you get a JS error, the browser may show something unhelpful like: [91mรขโ€”ห†[39m Function invocation failed: [object Object - the command line (where you are running netlify dev will show something a lot more helpful.

9:11pm

Calling it a night, an hour and a half, not bad going. A lot of it tended to be Slack API stuff rather than Netlify.

I now have a function I can call from a web interface, being the following to set the status:

/.netlify/functions/sitrep?action=update&stausCode=1

or the following to get it:

/.netlify/functions/sitrep?action=get

The statusCode represents some predefined statuses.

All the code can be found on Gitlab. The first thing I need to do is get the Slack oAuth token running off an environment variable - I realise i can do process.env.XXX to use XXX in the netlify interface, but not sure how I use it locally.

I did manage to also run a netlify deploy to get the code up on the live environment. One thing to note - I needed to log into the web interface to "publish" the deployment

To do:

  • Use environment variables for the Slack bearer - This can be found in Part 2
  • Lock functions down to IP address (maybe with an extra auth token?) so it can't be updated by anyone - This can be found in Part 2
  • Create a front-end to call the different URLs for quick status update
  • Turn into a PWA so it can be installed

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Mike Street

Written by Mike Street

Mike is a front-end developer from Brighton, UK. He spends his time writing, cycling and coding. You can find Mike on Twitter.