eproxus

Extending the Erlang Shell

Erlang makes it possible to extend the Erlang shell with your own built-in functions using the special module user_default. We can use this to add functions to the shell, and even add custom libraries to the code path for all Erlang shells.

How To Setup

1. Start by creating a file called .erlang in your home directory. Any Erlang expression ending with a dot in this file will be executed when the Erlang shell starts
2. Create the directory ~/.erlang.d:

   $ mkdir ~/.erlang.d

eproxus

OP-Z Automated Backup for macOS

Setup

1. Store backup.sh somewhere and make it executable:

   $ vim ~/Music/OP-Z/Backups/Support/backup.sh

   (The file opz_backup.sh is only needed as a convenience shortut to manually run the backup)

eproxus

1. Go to Menu → Help → More troubleshooting information → Application Basics → Profile Folder → Open Folder
2. Create a folder named chrome
3. Create a new text file inside chrome named userChrome.css and paste the content
4. Go to about:config in Firefox
5. Change the setting toolkit.legacyUserProfileCustomizations.stylesheets to true
6. Restart Firefox

eproxus

Erlang GitHub Actions With setup-beam and Caching

To build and test Erlang projects on GitHub actions with Rebar 3 it is fastest to use the setup-beam action and use caching.

To get started, create a workflow file in .github/workflows in your repository. For this example we use a file called .github/workflows/continuous_integration.yml.

eproxus

How to Create a Cowboy Stream Handler

Add your stream handler to the list of stream handlers in the protocol options:

{ok, Pid} = cowboy:start_clear(ListenerName,
    [{port, Port}],
    #{
        env => #{dispatch => Dispatch},
 stream_handlers => [my_stream_h, cowboy_compress_h, cowboy_stream_h]

eproxus

How to Create a Cowboy Middleware

⚠️
Middlewares are "deprecated" because stream handlers can do everything middlewares can do and more. Consider using a stream handler instead.

Add an entry to the middlewares. Usually you want to keep the standard Cowboy handlers afterwards, but you can replace them if you want.

eproxus

-module().

-behavior(gen_event).

% Callbacks
-export([init/1]).
-export([handle_event/2]).
-export([handle_call/2]).
-export([handle_info/2]).
-export([terminate/2]).

eproxus

# Load Order    Interactive Interactive Script
# Startup       Only login  Always
# ------------- ----------- ----------- ------
#  /etc/zshenv       1           1        1
#    ~/.zshenv       2           2        2
# /etc/zprofile      3
#   ~/.zprofile      4
# /etc/zshrc         5           3
#   ~/.zshrc         6           4
# /etc/zlogin        7

eproxus

-module().

-behavior(gen_server).

% API
-export([start_link/0]).

% Callbacks
-export([init/1]).
-export([handle_call/3]).

eproxus

@-webkit-keyframes fadein {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

#sVim-command {