Merge pull request #143 from polvalente/fix/dont-require-tesla-or-htt…

…poison

fix: don't require Tesla or HTTPoison

README.md

@@ -38,6 +38,14 @@ config :reverse_proxy_plug, :http_client, ReverseProxyPlug.HTTPClient.Adapters.H
 config :reverse_proxy_plug, :http_client, ReverseProxyPlug.HTTPClient.Adapters.Tesla
 ```
 
+You can also set the config as a per-plug basis, which will override any global config.
+Either of those must be set, otherwise the system will attempt to default to the HTTPoison
+adapter or raise if it's not present.
+
+```elixir
+plug ReverseProxyPlug, client: ReverseProxyPlug.HTTPClient.Adapters.Tesla
+```
+
 ## Usage
 
 The plug works best when used with

config/config.exs

@@ -27,4 +27,3 @@ use Mix.Config
 # Configuration from the imported file will override the ones defined
 # here (which is why it is important to import them last).
 #
-# import_config "#{Mix.env()}.exs"

lib/reverse_proxy_plug.ex

@@ -31,8 +31,8 @@ defmodule ReverseProxyPlug do
     end
 
     opts
+    |> ensure_http_client()
     |> Keyword.merge(upstream_parts)
-    |> Keyword.put_new(:client, http_client())
     |> Keyword.put_new(:client_options, [])
     |> Keyword.put_new(:response_mode, :stream)
     |> Keyword.put_new(:status_callbacks, %{})
@@ -413,11 +413,19 @@ defmodule ReverseProxyPlug do
     "#{host}:#{port}"
   end
 
-  defp http_client do
-    Application.get_env(
-      :reverse_proxy_plug,
-      :http_client,
-      HTTPClient.Adapters.HTTPoison
-    )
+  defp ensure_http_client(opts) do
+    client = opts[:client] || Application.get_env(:reverse_proxy_plug, :http_client)
+
+    cond do
+      not is_nil(client) ->
+        Keyword.put(opts, :client, client)
+
+      Code.ensure_loaded?(HTTPClient.Adapters.HTTPoison) and is_nil(client) ->
+        Keyword.put(opts, :client, HTTPClient.Adapters.HTTPoison)
+
+      true ->
+        raise ArgumentError,
+              ":client option or :reverse_proxy_plug, :http_client global config must be set"
+    end
   end
 end

lib/reverse_proxy_plug/http_client.ex

@@ -10,7 +10,4 @@ defmodule ReverseProxyPlug.HTTPClient do
                | __MODULE__.AsyncResponse.t()
                | __MODULE__.MaybeRedirect.t()}
               | {:error, error()}
-
-  if !Code.ensure_loaded?(HTTPoison) && !Code.ensure_loaded?(Tesla),
-    do: raise("Either http_poison or tesla must be available")
 end

mix.exs

@@ -56,7 +56,7 @@ defmodule ReverseProxyPlug.MixProject do
       {:credo, "~> 1.0", only: [:dev, :test]},
       {:mox, "~> 1.0", only: :test, optional: true},
       {:ex_doc, ">= 0.0.0", only: :dev, runtime: false},
-      {:tesla, "~> 1.4.1", optional: true},
+      {:tesla, "~> 1.4", optional: true},
       {:bypass, "~> 2.1.0", optional: true, only: :test}
     ]
   end

test/reverse_proxy_plug_test.exs

@@ -594,11 +594,56 @@ defmodule ReverseProxyPlugTest do
 
       plug(ReverseProxyPlug,
         upstream: "",
-        error_callback: {__MODULE__, :error_handler, []}
+        error_callback: {__MODULE__, :error_handler, []},
+        client: ReverseProxyPlug.HTTPClient.Adapters.HTTPoison
       )
     end
   end
 
+  test "must be initialized with either global or local config set" do
+    prev = Application.get_env(:reverse_proxy_plug, :http_client)
+
+    on_exit(fn -> Application.put_env(:reverse_proxy_plug, :http_client, prev) end)
+
+    Application.put_env(:reverse_proxy_plug, :http_client, nil)
+
+    # Ensure it defaults to HTTPoison for retrocompatibility
+
+    assert opts =
+             ReverseProxyPlug.init(
+               upstream: "",
+               error_callback: {__MODULE__, :error_handler, []}
+             )
+
+    assert opts[:client] == ReverseProxyPlug.HTTPClient.Adapters.HTTPoison
+
+    adapter = MyCustomAdapter
+
+    assert opts =
+             ReverseProxyPlug.init(
+               upstream: "",
+               error_callback: {__MODULE__, :error_handler, []},
+               client: adapter
+             )
+
+    assert adapter == opts[:client]
+
+    Application.put_env(
+      :reverse_proxy_plug,
+      :http_client,
+      adapter
+    )
+
+    assert opts =
+             ReverseProxyPlug.init(
+               upstream: "",
+               error_callback: {__MODULE__, :error_handler, []},
+               client: nil
+             )
+
+    assert adapter == opts[:client]
+  end
+
   test_stream_and_buffer "recycles cookies from connection" do
     %{opts: opts, get_responder: get_responder} = test_reuse_opts