Add an AdapterHelper for Finch so we can support streaming request bodies

lib/pleroma/http/adapter_helper.ex

@@ -52,6 +52,7 @@ defmodule Pleroma.HTTP.AdapterHelper do
     case adapter() do
       Tesla.Adapter.Gun -> AdapterHelper.Gun
       Tesla.Adapter.Hackney -> AdapterHelper.Hackney
+      {Tesla.Adapter.Finch, _} -> AdapterHelper.Finch
       _ -> AdapterHelper.Default
     end
   end
@@ -124,6 +125,7 @@ defmodule Pleroma.HTTP.AdapterHelper do
   def can_stream? do
     case Application.get_env(:tesla, :adapter) do
       Tesla.Adapter.Gun -> true
+      {Tesla.Adapter.Finch, _} -> true
       _ -> false
     end
   end

lib/pleroma/http/adapter_helper/finch.ex

@@ -0,0 +1,33 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.HTTP.AdapterHelper.Finch do
+  @behaviour Pleroma.HTTP.AdapterHelper
+
+  alias Pleroma.Config
+  alias Pleroma.HTTP.AdapterHelper
+
+  @spec options(keyword(), URI.t()) :: keyword()
+  def options(incoming_opts \\ [], %URI{} = _uri) do
+    proxy =
+      [:http, :proxy_url]
+      |> Config.get()
+      |> AdapterHelper.format_proxy()
+
+    config_opts = Config.get([:http, :adapter], [])
+
+    config_opts
+    |> Keyword.merge(incoming_opts)
+    |> AdapterHelper.maybe_add_proxy(proxy)
+    |> maybe_stream()
+  end
+
+  # Tesla Finch adapter uses response: :stream
+  defp maybe_stream(opts) do
+    case Keyword.pop(opts, :stream, nil) do
+      {true, opts} -> Keyword.put(opts, :response, :stream)
+      {_, opts} -> opts
+    end
+  end
+end