[FIXED] How Can I Find Default User Directories in Elixir

Issue

In many programming languages, there is a library call (part of the base packages or an external module) to locate the user's home directory, the documents directory, the configuration directory, and so forth, that isn't platform-specific. As an example of one that I've used recently for another language, Rust has "dirs." Is there an Elixir equivalent?

For example, I run a server on my local machine to handle some tasks, and recently wrote a client for it---a simple console application that sends a TCP request and gets a response---in Elixir. I would like to pull the port number from the existing configuration file, if the file exists, so that the value isn't hard-coded. I could do something like this, of course.

Path.join(System.user_home!(), ".config")

I guess System.user_home() is a start, itself, but not really sufficient. It'll fail miserably on a Windows machine, for example.

Searching the web turned up examples in plenty of non-Elixir languages, ways to search the current directory for a file in Elixir, and how to get the most out of the config directory in a Phoenix project, but nothing that I could see for just getting the configuration (or a similar) directory.

So, assuming that this has been done before (and I have to assume it has been, given how established Elixir has become), what's the current method for retrieving the user's configuration folder?

Solution

Not fully Elixir, but there is Erlang functions for that - filename:basedir/{2,3}

This function take the type of the directory as a first argument, which is one of the following atoms:

• user_cache
• user_config
• user_data
• user_log
• site_config
• site_data

And application name (also as atom) as a second argument.

Third argument may be a map containing:

• os - OS type used for the paths creation, there are 3 recognisable values - windows, darwin (macOS), and linux (which will use XDG Base Directory Spec). Any other value will be treated as linux. If not provided, then OS is automatically detected by os:type/0 call.
• author - used only on Windows
• version - used only on Windows

Answered By - Hauleth

Answer Checked By - Pedro (PHPFixing Volunteer)