Add supported languages list to /api/v2/instance

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>

lib/pleroma/language/translation.ex

@@ -6,9 +6,9 @@ defmodule Pleroma.Language.Translation do
   @cachex Pleroma.Config.get([:cachex, :provider], Cachex)
 
   def configured? do
-    service = get_service()
+    provider = get_provider()
 
-    !!service and service.configured?
+    !!provider and provider.configured?
   end
 
   def translate(text, source_language, target_language) do
@@ -16,13 +16,13 @@ defmodule Pleroma.Language.Translation do
 
     case @cachex.get(:translations_cache, cache_key) do
       {:ok, nil} ->
-        service = get_service()
+        provider = get_provider()
 
         result =
-          if !service or !service.configured? do
+          if !configured?() do
             {:error, :not_found}
           else
-            service.translate(text, source_language, target_language)
+            provider.translate(text, source_language, target_language)
           end
 
         store_result(result, cache_key)
@@ -37,7 +37,33 @@ defmodule Pleroma.Language.Translation do
     end
   end
 
-  defp get_service, do: Pleroma.Config.get([__MODULE__, :provider])
+  def supported_languages(type) when type in [:source, :target] do
+    provider = get_provider()
+
+    cache_key = "#{type}_languages/#{provider.name()}"
+
+    case @cachex.get(:translations_cache, cache_key) do
+      {:ok, nil} ->
+        result =
+          if !configured?() do
+            {:error, :not_found}
+          else
+            provider.supported_languages(type)
+          end
+
+        store_result(result, cache_key)
+
+        result
+
+      {:ok, result} ->
+        {:ok, result}
+
+      {:error, error} ->
+        {:error, error}
+    end
+  end
+
+  defp get_provider, do: Pleroma.Config.get([__MODULE__, :provider])
 
   defp get_cache_key(text, source_language, target_language) do
     "#{source_language}/#{target_language}/#{content_hash(text)}"

lib/pleroma/language/translation/deepl.ex

@@ -9,14 +9,17 @@ defmodule Pleroma.Language.Translation.Deepl do
 
   @behaviour Provider
 
+  @name "DeepL"
+
   @impl Provider
-  def configured? do
-    is_atom(get_base_url()) and not_empty_string(get_api_key())
-  end
+  def configured?, do: not_empty_string(base_url()) and not_empty_string(api_key())
 
   @impl Provider
   def translate(content, source_language, target_language) do
-    endpoint = get_base_url()
+    endpoint =
+      base_url()
+      |> URI.merge("/v2/translate")
+      |> URI.to_string()
 
     case Pleroma.HTTP.post(
            endpoint <>
@@ -30,7 +33,7 @@ defmodule Pleroma.Language.Translation.Deepl do
            "",
            [
              {"Content-Type", "application/x-www-form-urlencoded"},
-             {"Authorization", "DeepL-Auth-Key #{get_api_key()}"}
+             {"Authorization", "DeepL-Auth-Key #{api_key()}"}
            ]
          ) do
       {:ok, %{status: 429}} ->
@@ -50,7 +53,7 @@ defmodule Pleroma.Language.Translation.Deepl do
          %{
            content: content,
            detected_source_language: detected_source_language,
-           provider: "DeepL"
+           provider: @name
          }}
 
       _ ->
@@ -58,11 +61,41 @@ defmodule Pleroma.Language.Translation.Deepl do
     end
   end
 
-  defp get_base_url do
+  @impl Provider
+  def supported_languages(type) when type in [:source, :target] do
+    endpoint =
+      base_url()
+      |> URI.merge("/v2/languages")
+      |> URI.to_string()
+
+    case Pleroma.HTTP.post(
+           endpoint <> "?" <> URI.encode_query(%{type: type}),
+           "",
+           [
+             {"Content-Type", "application/x-www-form-urlencoded"},
+             {"Authorization", "DeepL-Auth-Key #{api_key()}"}
+           ]
+         ) do
+      {:ok, %{status: 200} = res} ->
+        languages =
+          Jason.decode!(res.body)
+          |> Enum.map(fn %{"language" => language} -> language |> String.downcase() end)
+
+        {:ok, languages}
+
+      _ ->
+        {:error, :internal_server_error}
+    end
+  end
+
+  @impl Provider
+  def name, do: @name
+
+  defp base_url do
     Pleroma.Config.get([__MODULE__, :base_url])
   end
 
-  defp get_api_key do
+  defp api_key do
     Pleroma.Config.get([__MODULE__, :api_key])
   end
 end

lib/pleroma/language/translation/libretranslate.ex

@@ -9,21 +9,21 @@ defmodule Pleroma.Language.Translation.Libretranslate do
 
   @behaviour Provider
 
+  @name "LibreTranslate"
+
   @impl Provider
-  def configured?, do: not_empty_string(get_base_url())
+  def configured?, do: not_empty_string(base_url()) and not_empty_string(api_key())
 
   @impl Provider
   def translate(content, source_language, target_language) do
-    endpoint = endpoint_url()
-
     case Pleroma.HTTP.post(
-           endpoint,
+           base_url() <> "/translate",
            Jason.encode!(%{
              q: content,
              source: source_language |> String.upcase(),
              target: target_language,
              format: "html",
-             api_key: get_api_key()
+             api_key: api_key()
            }),
            [
              {"Content-Type", "application/json"}
@@ -52,15 +52,29 @@ defmodule Pleroma.Language.Translation.Libretranslate do
     end
   end
 
-  defp endpoint_url do
-    get_base_url() <> "/translate"
+  @impl Provider
+  def supported_languages(_) do
+    case Pleroma.HTTP.get(base_url() <> "/languages") do
+      {:ok, %{status: 200} = res} ->
+        languages =
+          Jason.decode!(res.body)
+          |> Enum.map(fn %{"code" => code} -> code end)
+
+        {:ok, languages}
+
+      _ ->
+        {:error, :internal_server_error}
+    end
   end
 
-  defp get_base_url do
+  @impl Provider
+  def name, do: @name
+
+  defp base_url do
     Pleroma.Config.get([__MODULE__, :base_url])
   end
 
-  defp get_api_key do
+  defp api_key do
     Pleroma.Config.get([__MODULE__, :api_key], "")
   end
 end

lib/pleroma/language/translation/provider.ex

@@ -17,4 +17,9 @@ defmodule Pleroma.Language.Translation.Provider do
                  provider: String.t()
                }}
               | {:error, atom()}
+
+  @callback supported_languages(type :: :string | :target) ::
+              {:ok, [String.t()]} | {:error, atom()}
+
+  @callback name() :: String.t()
 end

lib/pleroma/web/mastodon_api/views/instance_view.ex

@@ -206,10 +206,32 @@ defmodule Pleroma.Web.MastodonAPI.InstanceView do
       vapid: %{
         public_key: Keyword.get(Pleroma.Web.Push.vapid_config(), :public_key)
       },
-      translation: %{enabled: Pleroma.Language.Translation.configured?()}
+      translation: translation_config()
     })
   end
 
+  defp translation_config do
+    enabled = Pleroma.Language.Translation.configured?()
+
+    source_languages =
+      case Pleroma.Language.Translation.supported_languages(:source) do
+        {:ok, languages} -> languages
+        _ -> nil
+      end
+
+    target_languages =
+      case Pleroma.Language.Translation.supported_languages(:target) do
+        {:ok, languages} -> languages
+        _ -> nil
+      end
+
+    %{
+      enabled: enabled,
+      source_languages: source_languages,
+      target_languages: target_languages
+    }
+  end
+
   defp pleroma_configuration(instance) do
     %{
       metadata: %{