From e5a9f27c6a8c57fdb242de4410e7c388037e2b49 Mon Sep 17 00:00:00 2001
From: "Vitor M. A. da Cruz" <vitormazzi@gmail.com>
Date: Mon, 5 Aug 2024 17:09:36 -0300
Subject: [PATCH] improvement: enable custom `http_adapters` (#760)

Allow users to customize the behavior of the http client used by the oauth-based strategies
by configuring a http adapter.
---
 lib/ash_authentication.ex                        | 12 ++++++++++++
 lib/ash_authentication/strategies/oauth2/plug.ex | 12 +++++++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/lib/ash_authentication.ex b/lib/ash_authentication.ex
index ac6378f..48adff8 100644
--- a/lib/ash_authentication.ex
+++ b/lib/ash_authentication.ex
@@ -67,6 +67,18 @@ defmodule AshAuthentication do
   3. `AshAuthentication.Strategy.MagicLink`
      - authenticate by sending a single-use link to the user.
 
+  ### HTTP client settings
+
+  Most of the authentication strategies based on `OAuth2` wrap the [`assent`](https://hex.pm/packages/assent) package.
+
+  If you needs to customize the behavior of the http client used by `assent`, define a custom `http_adapter` in the 
+  application settings:
+
+  `config :ash_authentication, :http_adapter, {Assent.HTTPAdapter.Finch, supervisor: MyApp.CustomFinch}`
+
+  See [`assent's documentation`](https://hexdocs.pm/assent/README.html#http-client) for more details on the supported 
+  http clients and their configuration.
+
   ## Add-ons
 
   Add-ons are like strategies, except that they don't actually provide
diff --git a/lib/ash_authentication/strategies/oauth2/plug.ex b/lib/ash_authentication/strategies/oauth2/plug.ex
index 0525c92..47a6247 100644
--- a/lib/ash_authentication/strategies/oauth2/plug.ex
+++ b/lib/ash_authentication/strategies/oauth2/plug.ex
@@ -82,13 +82,13 @@ defmodule AshAuthentication.Strategy.OAuth2.Plug do
     config =
       strategy
       |> Map.take(@raw_config_attrs)
-      |> Map.put(:http_adapter, {Finch, supervisor: AshAuthentication.Finch})
 
     with {:ok, config} <- add_secret_value(config, strategy, :base_url),
          {:ok, config} <- add_secret_value(config, strategy, :authorize_url, !!strategy.base_url),
          {:ok, config} <- add_secret_value(config, strategy, :client_id, !!strategy.base_url),
          {:ok, config} <- add_secret_value(config, strategy, :client_secret, !!strategy.base_url),
          {:ok, config} <- add_secret_value(config, strategy, :token_url, !!strategy.base_url),
+         {:ok, config} <- add_http_adapter(config),
          {:ok, config} <-
            add_secret_value(
              config,
@@ -200,4 +200,14 @@ defmodule AshAuthentication.Strategy.OAuth2.Plug do
         {:error, reason}
     end
   end
+
+  defp add_http_adapter(config) do
+    http_adapter = Application.get_env(
+      :ash_authentication, 
+      :http_adapter, 
+      {Finch, supervisor: AshAuthentication.Finch}
+    )
+
+    {:ok, Map.put(config, :http_adapter, http_adapter)}
+  end
 end