Blazing fast Elixir configuration https://engineering.tripping.com/blazing-fast-elixir-configuration-475aca10011d

A few months ago, we decided to implement a users count feature on CaptainFact’s videos pages. It had to be reliable, light and simple. We also wanted to differentiate between logged-in and anonymous users.

The most interesting read I had at the time on this subject was a medium article which has one major flaw: the full users list is returned from the backend and the count occurs on the frontend (which actually respects the default behaviour of Phoenix.Presence).

Depending on your business, it can represent a privacy issue (you don’t especially want anyone to be able to know who’s connected to your channel) as well as a performance issue.

In the following article, I’ll show you how I implemented Phoenix.Presence in such a way that it only returns the total of connected / anonymous users. We’ll then see how to bind it to Redux.

https://blog.benjamin.piouffle.com/display-channel-users-count-elixir-phoenix-react-redux/

Simple sugar to make changing keys on maps less ugly.

What’s the why? When you consume information from a lot of API’s/sources, you get data streaming in with the keys from other applications, other applications naming conventions might not fit your app.

left <~> right, left is your map from outside your app, right is the rewrite rules.

It looks a little something like this: %{“id”=>”234923409”, “title”=>”asdf”}<~>[“title=>name”, “id=>shopify_id”]

Rewrite rules can be an Elixir List or a whitespace-separated list. They follow a format of left=>right, left is the old key, and right representing the new.

Add it as a dep: {:map_rewire, “~> 0.1.0”}

Hex.pm ~~ GitHub

My recent Nerves talk from Code BEAM STO: https://www.youtube.com/watch?v=IVCQvcCEjkU Want to learn more? Sign up for Nerves training at ElixirConf!

In this short episode, we continue exploring Elixir processes.

We build a countdown timer and another function that spawns it as a linked process. We see what happens when a linked process dies and how to handle such events without killing the parent process.

Excerpt:

But what if you would like to clean out your mix.lock file?

You know the drill, you stumble across some tutorial to do something you’d like to add to your Phoenix app, you update dependencies, try it out, then maybe decide it’s not what you want, or worth the effort.

Read on to clean out your mix.lock file

SmoothTerminal is giving away a copy of Phoenix in Action!

Phoenix in Action is an example-based tutorial that teaches you how to use the Phoenix framework to build production-quality web apps.

I wrote a blog post to wrap up my year as full-time Elixir developer, hope you like it https://medium.com/@lorenzo_sinisi/what-i-have-learned-working-1-year-with-full-time-using-elixir-51efd4c1f66

• New and improved Run/Debug configurations:
  • Distillery Release CLI,
  • elixir
  • iex
  • mix
  • mix test
  • iex -S mix.
• Evaluate in the debugger.
• More module filtering controls for debugger.
• Elixir 1.7 compatibility for debugger.
• All OTP 21 bytecodes can be disassembled.
• Spell Checking

Installation Instructions

Piggy-backing off my last post on generating all possible voicings for a given guitar chord, this week I used a “sieve”-inspired algorithm to generate all possible* fingerings for a given chord.

• For some values of “possible.”

It’s an excellent conference season and GigCityElixir is going to make your choices even harder. We’re bringing John Hughes (one of the creators of Haskell), Chris McCord (Phoenix), Prag Dave, James E Gray II and Bruce Tate with many others to scenic Chattanooga. https://www.gigcityelixir.com/

Performing bulk updates with Ecto and Elixir can be a pain. I compare three ways that you can do them. https://adamdelong.com/bulk-update-ecto

Organizing our Elixir code into modules, with related structs and functions all in one place, is great. Why not do that in JavaScript too?

https://blog.carbonfive.com/2018/08/13/a-proposal-elixir-style-modules-in-javascript

I have recently created a small library for managing user accounts through AWS Cognito service.

Cognitex

The following functionality is covered;

• User registration
• Confirm registration (with the confirmation code received from AWS, by email)
• User authentication
• Fetch user data by an access token
• Fetch user data by username
• Change user password
• Update user attributes
• Reset a forgotten password

Link to project https://github.com/Skoda091/cognitex

For my side project Gossip, I wanted to have a websocket connection for non-Phoenix connections. To do this I used Cowboy to create a socket handler.

https://blog.oestrich.org/2018/08/cowboy-websocket-handler/

Solution to Processes Challenge 1: Control one process with another

The challenge from last time was to create a module with two spawnable processes. One process is a counter and the second is a controller that spawns, starts it and terminates the counter.

https://github.com/ElixiumNetwork/elixium_core

SmoothTerminal is giving away two tickets to The Big Elixir conference in New Orleans, November 8-9!

I’m a keynote speaker (first time!) so I’m super excited to meet up with people there and see old friends!

Microsoft Excel and CSV don’t always play nicely together, especially when there’s non-ASCII characters involved.

Here’s an overview of how to generate CSV files that work well with Excel:

https://underthehood.meltwater.com/blog/2018/08/08/excel-friendly-csv-exports-with-elixir/

This screencast is an intro to Elixir processes. First we make the very simplest example of Elixir processes possible, and then we build on it.

The episode covers how to send, receive, spawn and kill Elixir processes.