Merge pull request #15 from felt/support-disabling-compile-time-http-…

…request

Support disabling compile time http request

README.md

@@ -32,7 +32,32 @@ iex> Domainatrex.parse("blog.someone.id.au")
 {:ok, %{domain: "someone", subdomain: "blog", tld: "id.au"}}
 ```
 
-
+## Configuration
+
+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+falling back to a local (potentially out of date) copy.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`:
+
+```elixir
+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"
+```
 
 ## Changelog
 

lib/domainatrex.ex

@@ -3,19 +3,25 @@ defmodule Domainatrex do
   @moduledoc """
   Documentation for Domainatrex.
   """
-  @public_suffix_list_url Application.get_env(:domainatrex, :public_suffix_list_url, 'https://raw.githubusercontent.com/publicsuffix/list/master/public_suffix_list.dat')
   @fallback_local_copy Application.get_env(:domainatrex, :fallback_local_copy, "lib/public_suffix_list.dat")
+  @fetch_latest Application.get_env(:domainatrex, :fetch_latest, true)
   @public_suffix_list nil
 
   :inets.start
   :ssl.start
-  case :httpc.request(:get, {@public_suffix_list_url, []}, [], []) do
-    {:ok, {_, _, string}} ->
-      @public_suffix_list to_string(string)
+
+  with true <- @fetch_latest,
+       public_suffix_list_url <- Application.get_env(:domainatrex, :public_suffix_list_url, 'https://raw.githubusercontent.com/publicsuffix/list/master/public_suffix_list.dat'),
+       {:ok, {_, _, string}} <- :httpc.request(:get, {public_suffix_list_url, []}, [], []) do
+    @public_suffix_list to_string(string)
+  else
     _ ->
       case File.read @fallback_local_copy do
         {:ok, string} ->
-          Logger.error "[Domainatrex] Could not read the public suffix list from the internet, trying to read from the backup at #{@fallback_local_copy}"
+          if @fetch_latest do
+            Logger.error "[Domainatrex] Could not read the public suffix list from the internet, trying to read from the backup at #{@fallback_local_copy}"
+          end
+
           @public_suffix_list string
         _ ->
           Logger.error "[Domainatrex] Could not read the public suffix list, please make sure that you either have an internet connection or #{@fallback_local_copy} exists"