Add the following to your mix.exs

defp deps do
  [{:domainatrex, "~> 3.0.2"}]

Domainatrex should be able to handle all valid hostnames, it uses the Public Suffix List and is heavily inspired by the fantastic Domainatrix library for Ruby

iex> Domainatrex.parse("someone.com")
{:ok, %{domain: "someone", subdomain: "", tld: "com"}}

iex> Domainatrex.parse("blog.someone.id.au")
{:ok, %{domain: "someone", subdomain: "blog", tld: "id.au"}}

For maximum performance, Domainatrex reads the list of all known top-level domains at compile time. Likewise, by default, the package will attempt to fetch the latest list of TLDs from the web before falling back to a local (potentially out of date) copy. You can configure this behavior in your config.exs as follows:

• :fetch_latest: A Boolean flag to determine whether Domainatrex should try to fetch the latest list of public suffixes at compile time; default is true
• :public_suffix_list_url: A charlist URL to the latest public suffix file that Domainatrex will try to fetch at compile time; default is 'https://raw.githubusercontent.com/publicsuffix/list/master/public_suffix_list.dat'
• :fallback_local_copy: The path to the local suffix file that Domainatrex will use if it wasn't able to fetch a fresh file from the URL, or if fetching updated files was disabled; default is the "lib/public_suffix_list.dat" file included in the package.

Here's a complete example of how you might customize this behavior in your confix.exs:

config :domainatrex,
  # Explicitly allow compile-time HTTP request to fetch the latest list of TLDs (default)
  fetch_latest: true,
  # Download the public suffix list from the official source (not necessarily tested with Domainatrex!)
  public_suffix_list_url: 'https://publicsuffix.org/list/public_suffix_list.dat',
  fallback_local_copy: "priv/my_app_custom_suffix_list.dat"

• Resolve warnings about SSL and Mix.Config being deprecated.

• Breaking change: default to including private domains. :include_private == false is still respected (but defaults to false), and a new env var :icann_only is added and defaults to false.

• Support disabling compile time http request with :fetch_latest config (thanks @s3cur3 for the PR!)

• Bump deps

• Use Logger for logging

• Pin a version of nimble_parsec to fix a compilation error on makeup (makeup has fixed this downstream, so when ex_doc updates makeup, this will no longer be required)

• Merge a couple of minor PRs

• Improve tests and docs slightly

• Privatise Domainatrex.match/n and Domainatrex.format_response/2 as they are only ever intended for internal use

• Better handle private domains. Private domains like *.s3.amazonaws.com are technically classed as TLDs (to my understanding?), it doesn't make a lot of sense to parse them this way.
• Fetch a new copy of the public suffix list from The Internet on compile, falling back to a (now updated!) local copy.

• Change the API from returning explicit results to {:ok, result} or {:error, result}. This is to be more uniform with other libraries I use and for better with usage. Sorry if this fucks up your day.

• Fully update the tests to reflect changes in 2.0.0 (thanks for the PR @pbonney!)