allow forcing a source language

lib/pleroma/akkoma/translators/deepl.ex

@@ -40,8 +40,9 @@ def languages do
   end
 
   @impl Pleroma.Akkoma.Translator
-  def translate(string, to_language) do
+  def translate(string, from_language, to_language) do
-    with {:ok, %{status: 200} = response} <- do_request(api_key(), tier(), string, to_language),
+    with {:ok, %{status: 200} = response} <-
+           do_request(api_key(), tier(), string, from_language, to_language),
          {:ok, body} <- Jason.decode(response.body) do
       %{"translations" => [%{"text" => translated, "detected_source_language" => detected}]} =
         body
@@ -57,7 +58,7 @@ def translate(string, to_language) do
     end
   end
 
-  defp do_request(api_key, tier, string, to_language) do
+  defp do_request(api_key, tier, string, from_language, to_language) do
     HTTP.post(
       base_url(tier) <> "translate",
       URI.encode_query(
@@ -65,7 +66,8 @@ defp do_request(api_key, tier, string, to_language) do
           text: string,
           target_lang: to_language,
           tag_handling: "html"
-        },
+        }
+        |> maybe_add_source(from_language),
         :rfc3986
       ),
       [
@@ -75,6 +77,9 @@ defp do_request(api_key, tier, string, to_language) do
     )
   end
 
+  defp maybe_add_source(opts, nil), do: opts
+  defp maybe_add_source(opts, lang), do: Map.put(opts, :source_lang, lang)
+
   defp do_languages() do
     HTTP.get(
       base_url(tier()) <> "languages?type=target",

lib/pleroma/akkoma/translators/libre_translate.ex

@@ -30,10 +30,17 @@ def languages do
   end
 
   @impl Pleroma.Akkoma.Translator
-  def translate(string, to_language) do
+  def translate(string, from_language, to_language) do
-    with {:ok, %{status: 200} = response} <- do_request(string, to_language),
+    with {:ok, %{status: 200} = response} <- do_request(string, from_language, to_language),
          {:ok, body} <- Jason.decode(response.body) do
-      %{"translatedText" => translated, "detectedLanguage" => %{"language" => detected}} = body
+      %{"translatedText" => translated} = body
+
+      detected =
+        if Map.has_key?(body, "detectedLanguage") do
+          get_in(body, ["detectedLanguage", "language"])
+        else
+          from_language
+        end
 
       {:ok, detected, translated}
     else
@@ -46,7 +53,7 @@ def translate(string, to_language) do
     end
   end
 
-  defp do_request(string, to_language) do
+  defp do_request(string, from_language, to_language) do
     url = URI.parse(url())
     url = %{url | path: "/translate"}
 
@@ -54,7 +61,7 @@ defp do_request(string, to_language) do
       to_string(url),
       Jason.encode!(%{
         q: string,
-        source: "auto",
+        source: if(is_nil(from_language), do: "auto", else: from_language),
         target: to_language,
         format: "html",
         api_key: api_key()

lib/pleroma/akkoma/translators/translator.ex

@@ -1,4 +1,5 @@
 defmodule Pleroma.Akkoma.Translator do
-  @callback translate(String.t(), String.t()) :: {:ok, String.t(), String.t()} | {:error, any()}
+  @callback translate(String.t(), String.t() | nil, String.t()) ::
+              {:ok, String.t(), String.t()} | {:error, any()}
   @callback languages() :: {:ok, [%{name: String.t(), code: String.t()}]} | {:error, any()}
 end

lib/pleroma/web/api_spec/operations/status_operation.ex

@@ -413,7 +413,7 @@ def translate_operation do
       description: "View the translation of a given status",
       operationId: "StatusController.translation",
       security: [%{"oAuth" => ["read:statuses"]}],
-      parameters: [id_param(), language_param()],
+      parameters: [id_param(), language_param(), source_language_param()],
       responses: %{
         200 => Operation.response("Translation", "application/json", translation()),
         400 => Operation.response("Error", "application/json", ApiError),
@@ -572,6 +572,10 @@ defp language_param do
     Operation.parameter(:language, :path, :string, "ISO 639 language code", example: "en")
   end
 
+  defp source_language_param do
+    Operation.parameter(:from, :query, :string, "ISO 639 language code", example: "en")
+  end
+
   defp status_response do
     Operation.response("Status", "application/json", Status)
   end

lib/pleroma/web/mastodon_api/controllers/status_controller.ex

@@ -422,7 +422,7 @@ def bookmarks(%{assigns: %{user: user}} = conn, params) do
   end
 
   @doc "GET /api/v1/statuses/:id/translations/:language"
-  def translate(%{assigns: %{user: user}} = conn, %{id: id, language: language}) do
+  def translate(%{assigns: %{user: user}} = conn, %{id: id, language: language} = params) do
     with {:enabled, true} <- {:enabled, Config.get([:translator, :enabled])},
          %Activity{} = activity <- Activity.get_by_id_with_object(id),
          {:visible, true} <- {:visible, Visibility.visible_for_user?(activity, user)},
@@ -431,6 +431,7 @@ def translate(%{assigns: %{user: user}} = conn, %{id: id, language: language}) d
            fetch_or_translate(
              activity.id,
              activity.object.data["content"],
+             Map.get(params, :from, nil),
              language,
              translation_module
            ) do
@@ -449,16 +450,20 @@ def translate(%{assigns: %{user: user}} = conn, %{id: id, language: language}) d
     end
   end
 
-  defp fetch_or_translate(status_id, text, language, translation_module) do
+  defp fetch_or_translate(status_id, text, source_language, target_language, translation_module) do
-    @cachex.fetch!(:translations_cache, "translations:#{status_id}:#{language}", fn _ ->
+    @cachex.fetch!(
-      value = translation_module.translate(text, language)
+      :translations_cache,
+      "translations:#{status_id}:#{source_language}:#{target_language}",
+      fn _ ->
+        value = translation_module.translate(text, source_language, target_language)
 
         with {:ok, _, _} <- value do
           value
         else
           _ -> {:ignore, value}
         end
-    end)
+      end
+    )
   end
 
   defp put_application(params, %{assigns: %{token: %Token{user: %User{} = user} = token}} = _conn) do

test/pleroma/translators/deepl_test.exs

@@ -60,7 +60,7 @@ test "should work with the free tier" do
           }
       end)
 
-      assert {:ok, "ja", "I will crush you"} = DeepL.translate("ギュギュ握りつぶしちゃうぞ", "en")
+      assert {:ok, "ja", "I will crush you"} = DeepL.translate("ギュギュ握りつぶしちゃうぞ", nil, "en")
     end
 
     test "should work with the pro tier" do
@@ -85,7 +85,33 @@ test "should work with the pro tier" do
           }
       end)
 
-      assert {:ok, "ja", "I will crush you"} = DeepL.translate("ギュギュ握りつぶしちゃうぞ", "en")
+      assert {:ok, "ja", "I will crush you"} = DeepL.translate("ギュギュ握りつぶしちゃうぞ", nil, "en")
+    end
+
+    test "should assign source language if set" do
+      clear_config([:deepl, :tier], :pro)
+
+      Tesla.Mock.mock(fn
+        %{method: :post, url: "https://api.deepl.com/v2/translate"} = env ->
+          auth_header = Enum.find(env.headers, fn {k, _v} -> k == "authorization" end)
+          assert {"authorization", "DeepL-Auth-Key deepl_api_key"} = auth_header
+          assert String.contains?(env.body, "source_lang=ja")
+
+          %Tesla.Env{
+            status: 200,
+            body:
+              Jason.encode!(%{
+                translations: [
+                  %{
+                    "text" => "I will crush you",
+                    "detected_source_language" => "ja"
+                  }
+                ]
+              })
+          }
+      end)
+
+      assert {:ok, "ja", "I will crush you"} = DeepL.translate("ギュギュ握りつぶしちゃうぞ", "ja", "en")
     end
 
     test "should gracefully fail if the API errors" do
@@ -99,7 +125,8 @@ test "should gracefully fail if the API errors" do
           }
       end)
 
-      assert {:error, "DeepL request failed (code 403)"} = DeepL.translate("ギュギュ握りつぶしちゃうぞ", "en")
+      assert {:error, "DeepL request failed (code 403)"} =
+               DeepL.translate("ギュギュ握りつぶしちゃうぞ", nil, "en")
     end
   end
 end

test/pleroma/translators/libre_translate_test.exs

@@ -36,7 +36,7 @@ test "should list supported languages" do
     test "should work without an API key" do
       Tesla.Mock.mock(fn
         %{method: :post, url: "http://libre.translate/translate"} = env ->
-          assert {:ok, %{"api_key" => nil}} = Jason.decode(env.body)
+          assert {:ok, %{"api_key" => nil, "source" => "auto"}} = Jason.decode(env.body)
 
           %Tesla.Env{
             status: 200,
@@ -51,7 +51,8 @@ test "should work without an API key" do
           }
       end)
 
-      assert {:ok, "ja", "I will crush you"} = LibreTranslate.translate("ギュギュ握りつぶしちゃうぞ", "en")
+      assert {:ok, "ja", "I will crush you"} =
+               LibreTranslate.translate("ギュギュ握りつぶしちゃうぞ", nil, "en")
     end
 
     test "should work with an API key" do
@@ -74,7 +75,8 @@ test "should work with an API key" do
           }
       end)
 
-      assert {:ok, "ja", "I will crush you"} = LibreTranslate.translate("ギュギュ握りつぶしちゃうぞ", "en")
+      assert {:ok, "ja", "I will crush you"} =
+               LibreTranslate.translate("ギュギュ握りつぶしちゃうぞ", nil, "en")
     end
 
     test "should gracefully handle API key errors" do
@@ -92,7 +94,25 @@ test "should gracefully handle API key errors" do
       end)
 
       assert {:error, "libre_translate: request failed (code 403)"} =
-               LibreTranslate.translate("ギュギュ握りつぶしちゃうぞ", "en")
+               LibreTranslate.translate("ギュギュ握りつぶしちゃうぞ", nil, "en")
+    end
+
+    test "should set a source language if requested" do
+      Tesla.Mock.mock(fn
+        %{method: :post, url: "http://libre.translate/translate"} = env ->
+          assert {:ok, %{"api_key" => nil, "source" => "ja"}} = Jason.decode(env.body)
+
+          %Tesla.Env{
+            status: 200,
+            body:
+              Jason.encode!(%{
+                translatedText: "I will crush you"
+              })
+          }
+      end)
+
+      assert {:ok, "ja", "I will crush you"} =
+               LibreTranslate.translate("ギュギュ握りつぶしちゃうぞ", "ja", "en")
     end
 
     test "should gracefully handle an unsupported language" do
@@ -110,7 +130,7 @@ test "should gracefully handle an unsupported language" do
       end)
 
       assert {:error, "libre_translate: request failed (code 400)"} =
-               LibreTranslate.translate("ギュギュ握りつぶしちゃうぞ", "zoop")
+               LibreTranslate.translate("ギュギュ握りつぶしちゃうぞ", nil, "zoop")
     end
   end
 end