Add translation module for Argos Translate (#351)

Argos Translate is a Python module for translation and can be used as a command line tool.

This is also the engine for LibreTranslate, for which we already have a module.
Here we can use the engine directly from our server without doing requests to a third party or having to install our own LibreTranslate webservice (obviously you do have to install Argos Translate).

One thing that's currently still missing from Argos Translate is auto-detection of languages (see <https://github.com/argosopentech/argos-translate/issues/9>). For now, when no source language is provided, we just return the text unchanged, supposedly translated from the target language. That way you get a near immediate response in pleroma-fe when clicking Translate, after which you can select the source language from a dropdown.

Argos Translate also doesn't seem to handle html very well. Therefore we give admins the option to strip the html before translating. I made this an option because I'm unsure if/how this will change in the future.

Co-authored-by: ilja <git@ilja.space>
Reviewed-on: AkkomaGang/akkoma#351
Co-authored-by: ilja <akkoma.dev@ilja.space>
Co-committed-by: ilja <akkoma.dev@ilja.space>

CHANGELOG.md

@@ -9,6 +9,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Added
 - Prometheus metrics exporting from `/api/v1/akkoma/metrics`
 - Ability to alter http pool size
+- Translation of statuses via ArgosTranslate
 
 ### Removed
 - Non-finch HTTP adapters

config/config.exs

@@ -882,6 +882,11 @@
   url: "http://127.0.0.1:5000",
   api_key: nil
 
+config :pleroma, :argos_translate,
+  command_argos_translate: "argos-translate",
+  command_argospm: "argospm",
+  strip_html: true
+
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.
 import_config "#{Mix.env()}.exs"

config/description.exs

@@ -3442,5 +3442,30 @@
         suggestion: [nil]
       }
     ]
+  },
+  %{
+    group: :pleroma,
+    key: :argos_translate,
+    type: :group,
+    description: "ArgosTranslate Settings.",
+    children: [
+      %{
+        key: :command_argos_translate,
+        type: :string,
+        description: "command for `argos-translate`. Can be the command if it's in your PATH, or the full path to the file.",
+        suggestion: ["argos-translate"]
+      },
+      %{
+        key: :command_argospm,
+        type: :string,
+        description: "command for `argospm`. Can be the command if it's in your PATH, or the full path to the file.",
+        suggestion: ["argospm"]
+      },
+      %{
+        key: :strip_html,
+        type: :boolean,
+        description: "Strip html from the post before translating it."
+      }
+    ]
   }
 ]

docs/docs/configuration/cheatsheet.md

@@ -1119,7 +1119,7 @@ Each job has these settings:
 ### Translation Settings
 
 Settings to automatically translate statuses for end users. Currently supported
-translation services are DeepL and LibreTranslate.
+translation services are DeepL and LibreTranslate. The supported command line tool is [Argos Translate](https://github.com/argosopentech/argos-translate).
 
 Translations are available at `/api/v1/statuses/:id/translations/:language`, where
 `language` is the target language code (e.g `en`)
@@ -1128,7 +1128,7 @@ Translations are available at `/api/v1/statuses/:id/translations/:language`, whe
 
 - `:enabled` - enables translation
 - `:module` - Sets module to be used
-  - Either `Pleroma.Akkoma.Translators.DeepL` or `Pleroma.Akkoma.Translators.LibreTranslate`
+  - Either `Pleroma.Akkoma.Translators.DeepL`, `Pleroma.Akkoma.Translators.LibreTranslate`, or `Pleroma.Akkoma.Translators.ArgosTranslate`
 
 ### `:deepl`
 
@@ -1140,3 +1140,9 @@ Translations are available at `/api/v1/statuses/:id/translations/:language`, whe
 
 - `:url` - URL of LibreTranslate instance
 - `:api_key` - API key for LibreTranslate
+
+### `:argos_translate`
+
+- `:command_argos_translate` - command for `argos-translate`. Can be the command if it's in your PATH, or the full path to the file  (default: `argos-translate`).
+- `:command_argospm` - command for `argospm`. Can be the command if it's in your PATH, or the full path to the file (default: `argospm`).
+- `:strip_html` - Strip html from the post before translating it (default: `true`).

lib/pleroma/akkoma/translators/argos_translate.ex

@@ -0,0 +1,109 @@
+defmodule Pleroma.Akkoma.Translators.ArgosTranslate do
+  @behaviour Pleroma.Akkoma.Translator
+
+  alias Pleroma.Config
+
+  defp argos_translate do
+    Config.get([:argos_translate, :command_argos_translate])
+  end
+
+  defp argospm do
+    Config.get([:argos_translate, :command_argospm])
+  end
+
+  defp strip_html? do
+    Config.get([:argos_translate, :strip_html])
+  end
+
+  defp safe_languages() do
+    try do
+      System.cmd(argospm(), ["list"], stderr_to_stdout: true, parallelism: true)
+    rescue
+      _ -> {"Command #{argospm()} not found", 1}
+    end
+  end
+
+  @impl Pleroma.Akkoma.Translator
+  def languages do
+    with {response, 0} <- safe_languages() do
+      langs =
+        response
+        |> String.split("\n", trim: true)
+        |> Enum.map(fn
+          "translate-" <> l -> String.split(l, "_")
+        end)
+
+      source_langs =
+        langs
+        |> Enum.map(fn [l, _] -> %{code: l, name: l} end)
+        |> Enum.uniq()
+
+      dest_langs =
+        langs
+        |> Enum.map(fn [_, l] -> %{code: l, name: l} end)
+        |> Enum.uniq()
+
+      {:ok, source_langs, dest_langs}
+    else
+      {response, _} -> {:error, "ArgosTranslate failed to fetch languages (#{response})"}
+    end
+  end
+
+  defp safe_translate(string, from_language, to_language) do
+    try do
+      System.cmd(
+        argos_translate(),
+        ["--from-lang", from_language, "--to-lang", to_language, string],
+        stderr_to_stdout: true,
+        parallelism: true
+      )
+    rescue
+      _ -> {"Command #{argos_translate()} not found", 1}
+    end
+  end
+
+  defp clean_string(string, true) do
+    string
+    |> String.replace("<p>", "\n")
+    |> String.replace("</p>", "\n")
+    |> String.replace("<br>", "\n")
+    |> String.replace("<br/>", "\n")
+    |> String.replace("<li>", "\n")
+    |> Pleroma.HTML.strip_tags()
+    |> HtmlEntities.decode()
+  end
+
+  defp clean_string(string, _), do: string
+
+  defp htmlify_response(string, true) do
+    string
+    |> HtmlEntities.encode()
+    |> String.replace("\n", "<br/>")
+  end
+
+  defp htmlify_response(string, _), do: string
+
+  @impl Pleroma.Akkoma.Translator
+  def translate(string, nil, to_language) do
+    # Akkoma's Pleroma-fe expects us to detect the source language automatically.
+    # Argos-translate doesn't have that option (yet?)
+    #     see <https://github.com/argosopentech/argos-translate/issues/9>
+    # For now we return the text unchanged, supposedly translated from the target language.
+    # Afterwards people get the option to overwrite the source language from a dropdown.
+    {:ok, to_language, string}
+  end
+
+  def translate(string, from_language, to_language) do
+    # Argos Translate doesn't properly translate HTML (yet?)
+    # For now we give admins the option to strip the html before translating
+    # Note that we have to add some html back to the response afterwards
+    string = clean_string(string, strip_html?())
+
+    with {translated, 0} <-
+           safe_translate(string, from_language, to_language) do
+      {:ok, from_language, translated |> htmlify_response(strip_html?())}
+    else
+      {response, _} -> {:error, "ArgosTranslate failed to translate (#{response})"}
+    end
+  end
+end

test/pleroma/akkoma/translators/argos_translate_test.exs

@@ -0,0 +1,93 @@
+defmodule Pleroma.Akkoma.Translators.ArgosTranslateTest do
+  alias Pleroma.Akkoma.Translators.ArgosTranslate
+
+  import Mock
+
+  use Pleroma.DataCase, async: true
+
+  setup do
+    clear_config([:argos_translate, :command_argos_translate], "argos-translate_test")
+    clear_config([:argos_translate, :command_argospm], "argospm_test")
+  end
+
+  test "it lists available languages" do
+    languages =
+      with_mock System, [:passthrough],
+        cmd: fn "argospm_test", ["list"], _ ->
+          {"translate-nl_en\ntranslate-en_nl\ntranslate-ja_en\n", 0}
+        end do
+        ArgosTranslate.languages()
+      end
+
+    assert {:ok, source_langs, dest_langs} = languages
+
+    assert [%{code: "en", name: "en"}, %{code: "ja", name: "ja"}, %{code: "nl", name: "nl"}] =
+             source_langs |> Enum.sort()
+
+    assert [%{code: "en", name: "en"}, %{code: "nl", name: "nl"}] = dest_langs |> Enum.sort()
+  end
+
+  test "it translates from the to language when no language is set and returns the text unchanged" do
+    assert {:ok, "nl", "blabla"} = ArgosTranslate.translate("blabla", nil, "nl")
+  end
+
+  test "it translates from the provided language if provided" do
+    translation_response =
+      with_mock System, [:passthrough],
+        cmd: fn "argos-translate_test", ["--from-lang", "nl", "--to-lang", "en", "blabla"], _ ->
+          {"yadayada", 0}
+        end do
+        ArgosTranslate.translate("blabla", "nl", "en")
+      end
+
+    assert {:ok, "nl", "yadayada"} = translation_response
+  end
+
+  test "it returns a proper error when the executable can't be found" do
+    non_existing_command = "sfqsfgqsefd"
+    clear_config([:argos_translate, :command_argos_translate], non_existing_command)
+    clear_config([:argos_translate, :command_argospm], non_existing_command)
+
+    assert nil == System.find_executable(non_existing_command)
+
+    assert {:error, "ArgosTranslate failed to fetch languages" <> _} = ArgosTranslate.languages()
+
+    assert {:error, "ArgosTranslate failed to translate" <> _} =
+             ArgosTranslate.translate("blabla", "nl", "en")
+  end
+
+  test "it can strip html" do
+    content =
+      ~s[<p>What&#39;s up my fellow fedizens?</p><p>So anyway</p><ul><li><a class="hashtag" data-tag="cofe" href="https://suya.space/tag/cofe">#cofe</a></li><li><a class="hashtag" data-tag="suya" href="https://cofe.space/tag/suya">#Suya</a></li></ul><p>ammiright!<br/>:ablobfoxhyper:</p>]
+
+    stripped_content =
+      "\nWhat's up my fellow fedizens?\n\nSo anyway\n\n#cofe\n#Suya\nammiright!\n:ablobfoxhyper:\n"
+
+    expected_response_strip_html =
+      "<br/>What&#39;s up my fellow fedizens?<br/><br/>So anyway<br/><br/>#cofe<br/>#Suya<br/>ammiright!<br/>:ablobfoxhyper:<br/>"
+
+    response_strip_html =
+      with_mock System, [:passthrough],
+        cmd: fn "argos-translate_test",
+                ["--from-lang", _, "--to-lang", _, ^stripped_content],
+                _ ->
+          {stripped_content, 0}
+        end do
+        ArgosTranslate.translate(content, "nl", "en")
+      end
+
+    clear_config([:argos_translate, :strip_html], false)
+
+    response_no_strip_html =
+      with_mock System, [:passthrough],
+        cmd: fn "argos-translate_test", ["--from-lang", _, "--to-lang", _, string], _ ->
+          {string, 0}
+        end do
+        ArgosTranslate.translate(content, "nl", "en")
+      end
+
+    assert {:ok, "nl", content} == response_no_strip_html
+
+    assert {:ok, "nl", expected_response_strip_html} == response_strip_html
+  end
+end