Expose translation service availability

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

config/description.exs

@@ -3523,5 +3523,18 @@ config :pleroma, :config_description, [
         suggestion: [100_000]
       }
     ]
+  },
+  %{
+    group: :pleroma,
+    key: Pleroma.Translation,
+    type: :group,
+    description: "Translation providers",
+    children: [
+      %{
+        key: Pleroma.Translation,
+        type: :service,
+        suggestions: [Pleroma.Translation.DeepL, Pleroma.Translation.LibreTranslate]
+      }
+    ]
   }
 ]

lib/pleroma/translation.ex

@@ -0,0 +1,54 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Translation do
+  @cache_ttl 86_400_000
+  @cachex Pleroma.Config.get([:cachex, :provider], Cachex)
+
+  def configured? do
+    service = get_service()
+
+    !!service and service.configured?
+  end
+
+  def translate(text, source_language, target_language) do
+    cache_key = get_cache_key(text, source_language, target_language)
+
+    case @cachex.get(:translations_cache, cache_key) do
+      {:ok, nil} ->
+        service = get_service()
+
+        result =
+          if !service or !service.configured? do
+            {:error, :not_found}
+          else
+            service.translate(text, source_language, target_language)
+          end
+
+        store_result(result, cache_key)
+
+        result
+
+      {:ok, result} ->
+        {:ok, result}
+
+      {:error, error} ->
+        {:error, error}
+    end
+  end
+
+  defp get_service, do: Pleroma.Config.get([__MODULE__, :service])
+
+  defp get_cache_key(text, source_language, target_language) do
+    "#{source_language}/#{target_language}/#{content_hash(text)}"
+  end
+
+  defp store_result({:ok, result}, cache_key) do
+    @cachex.put(:translations_cache, cache_key, result, ttl: @cache_ttl)
+  end
+
+  defp store_result(_, _), do: nil
+
+  defp content_hash(text), do: :crypto.hash(:sha256, text) |> Base.encode64()
+end

lib/pleroma/translation/deepl.ex

@@ -0,0 +1,75 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Translation.DeepL do
+  import Pleroma.Web.Utils.Guards, only: [not_empty_string: 1]
+
+  alias Pleroma.Translation.Service
+
+  @behaviour Service
+
+  @impl Service
+  def configured? do
+    not_empty_string(get_plan()) and not_empty_string(get_api_key())
+  end
+
+  @impl Service
+  def translate(content, source_language, target_language) do
+    endpoint = endpoint_url()
+
+    case Pleroma.HTTP.post(
+           endpoint <>
+             "?" <>
+             URI.encode_query(%{
+               text: content,
+               source_lang: source_language |> String.upcase(),
+               target_lang: target_language,
+               tag_handling: "html"
+             }),
+           "",
+           [
+             {"Content-Type", "application/x-www-form-urlencoded"},
+             {"Authorization", "DeepL-Auth-Key #{get_api_key()}"}
+           ]
+         ) do
+      {:ok, %{status: 429}} ->
+        {:error, :too_many_requests}
+
+      {:ok, %{status: 456}} ->
+        {:error, :quota_exceeded}
+
+      {:ok, %{status: 200} = res} ->
+        %{
+          "translations" => [
+            %{"text" => content, "detected_source_language" => detected_source_language}
+          ]
+        } = Jason.decode!(res.body)
+
+        {:ok,
+         %{
+           content: content,
+           detected_source_language: detected_source_language,
+           provider: "DeepL"
+         }}
+
+      _ ->
+        {:error, :internal_server_error}
+    end
+  end
+
+  defp endpoint_url do
+    case get_plan() do
+      "free" -> "https://api-free.deepl.com/v2/translate"
+      _ -> "https://api.deepl.com/v2/translate"
+    end
+  end
+
+  defp get_plan do
+    Pleroma.Config.get([__MODULE__, :plan])
+  end
+
+  defp get_api_key do
+    Pleroma.Config.get([__MODULE__, :api_key])
+  end
+end

lib/pleroma/translation/libretranslate.ex

@@ -0,0 +1,66 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Translation.LibreTranslate do
+  import Pleroma.Web.Utils.Guards, only: [not_empty_string: 1]
+
+  alias Pleroma.Translation.Service
+
+  @behaviour Service
+
+  @impl Service
+  def configured?, do: not_empty_string(get_base_url())
+
+  @impl Service
+  def translate(content, source_language, target_language) do
+    endpoint = endpoint_url()
+
+    case Pleroma.HTTP.post(
+           endpoint,
+           Jason.encode!(%{
+             q: content,
+             source: source_language |> String.upcase(),
+             target: target_language,
+             format: "html",
+             api_key: get_api_key()
+           }),
+           [
+             {"Content-Type", "application/json"}
+           ]
+         ) do
+      {:ok, %{status: 429}} ->
+        {:error, :too_many_requests}
+
+      {:ok, %{status: 403}} ->
+        {:error, :quota_exceeded}
+
+      {:ok, %{status: 200} = res} ->
+        %{
+          "translatedText" => content
+        } = Jason.decode!(res.body)
+
+        {:ok,
+         %{
+           content: content,
+           detected_source_language: source_language,
+           provider: "LibreTranslate"
+         }}
+
+      _ ->
+        {:error, :internal_server_error}
+    end
+  end
+
+  defp endpoint_url do
+    get_base_url() <> "/translate"
+  end
+
+  defp get_base_url do
+    Pleroma.Config.get([__MODULE__, :base_url])
+  end
+
+  defp get_api_key do
+    Pleroma.Config.get([__MODULE__, :api_key], "")
+  end
+end

lib/pleroma/translation/service.ex

@@ -0,0 +1,20 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Translation.Service do
+  @callback configured?() :: boolean()
+
+  @callback translate(
+              content :: String.t(),
+              source_language :: String.t(),
+              target_language :: String.t()
+            ) ::
+              {:ok,
+               %{
+                 content: String.t(),
+                 detected_source_language: String.t(),
+                 provider: String.t()
+               }}
+              | {:error, atom()}
+end

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

@@ -433,9 +433,9 @@ defmodule Pleroma.Web.ApiSpec.StatusOperation do
           required: false
         ),
       responses: %{
-        200 => Operation.response("Translation", "application/json", translation())
-        400 => Operation.response("Error", "application/json", ApiError)
-        404 => Operation.response("Error", "application/json", ApiError)
+        200 => Operation.response("Translation", "application/json", translation()),
+        400 => Operation.response("Error", "application/json", ApiError),
+        404 => Operation.response("Error", "application/json", ApiError),
         503 => Operation.response("Error", "application/json", ApiError)
       }
     }

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

@@ -202,7 +202,8 @@ defmodule Pleroma.Web.MastodonAPI.InstanceView do
       },
       vapid: %{
         public_key: Keyword.get(Pleroma.Web.Push.vapid_config(), :public_key)
-      }
+      },
+      translation: %{enabled: Pleroma.Translation.configured?}
     })
   end