FEATURE: translate topic (#130)

Currently, only posts are being translated. When a post is the first post, we should include information about the topic.

Meta https://meta.discourse.org/t/feature-request-topic-title-translation/144714

assets/javascripts/discourse/initializers/extend-for-translate-button.js

@@ -11,6 +11,7 @@ function translatePost(post) {
     post.setProperties({
       translated_text: res.translation,
       detected_lang: res.detected_lang,
+      translated_title: res.title_translation,
     });
   });
 }
@@ -29,7 +30,8 @@ function initializeTranslation(api) {
   api.includePostAttributes(
     "can_translate",
     "translated_text",
-    "detected_lang"
+    "detected_lang",
+    "translated_title"
   );
 
   api.decorateWidget("post-menu:before", (dec) => {
@@ -44,8 +46,17 @@ function initializeTranslation(api) {
     const language = dec.attrs.detected_lang;
     const translator = siteSettings.translator;
 
+    let titleElements = [];
+
+    if (dec.attrs.translated_title) {
+      titleElements = [
+        dec.h("div.topic-attribution", dec.attrs.translated_title),
+      ];
+    }
+
     return dec.h("div.post-translation", [
       dec.h("hr"),
+      ...titleElements,
       dec.h(
         "div.post-attribution",
         I18n.t("translator.translated_from", { language, translator })

assets/stylesheets/common/post.scss

@@ -1,3 +1,8 @@
+.topic-attribution {
+  font-weight: bold;
+  margin-bottom: 1em;
+  margin-top: 1em;
+}
 .post-attribution {
   color: #8899a6;
   font-size: 12px;

config/settings.yml

@@ -94,6 +94,6 @@ discourse_translator:
     client: true
     type: group_list
   restrict_translation_by_poster_group:
-    default: "" 
+    default: ""
     client: true
     type: group_list

plugin.rb

@@ -73,16 +73,24 @@ def translate
       end
 
       begin
+        title_json = {}
         detected_lang, translation =
           "DiscourseTranslator::#{SiteSetting.translator}".constantize.translate(post)
-        render json: { translation: translation, detected_lang: detected_lang }, status: 200
+        if post.is_first_post?
+          _, title_translation =
+            "DiscourseTranslator::#{SiteSetting.translator}".constantize.translate(post.topic)
+          title_json = { title_translation: title_translation }
+        end
+        render json: { translation: translation, detected_lang: detected_lang }.merge(title_json),
+               status: 200
       rescue ::DiscourseTranslator::TranslatorError => e
         render_json_error e.message, status: 422
       end
     end
   end
 
   Post.register_custom_field_type(::DiscourseTranslator::TRANSLATED_CUSTOM_FIELD, :json)
+  Topic.register_custom_field_type(::DiscourseTranslator::TRANSLATED_CUSTOM_FIELD, :json)
 
   class ::Post < ActiveRecord::Base
     before_update :clear_translator_custom_fields, if: :raw_changed?
@@ -97,6 +105,19 @@ def clear_translator_custom_fields
     end
   end
 
+  class ::Topic < ActiveRecord::Base
+    before_update :clear_translator_custom_fields, if: :title_changed?
+
+    private
+
+    def clear_translator_custom_fields
+      return if !SiteSetting.translator_enabled
+
+      self.custom_fields.delete(DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD)
+      self.custom_fields.delete(DiscourseTranslator::TRANSLATED_CUSTOM_FIELD)
+    end
+  end
+
   module ::Jobs
     class TranslatorMigrateToAzurePortal < ::Jobs::Onceoff
       def execute_onceoff(args)

services/discourse_translator/amazon.rb

@@ -92,8 +92,8 @@ def self.access_token_key
       "aws-translator"
     end
 
-    def self.detect(post)
-      text = post.cooked.truncate(MAXLENGTH, omission: nil)
+    def self.detect(topic_or_post)
+      text = get_text(topic_or_post).truncate(MAXLENGTH, omission: nil)
 
       return if text.blank?
 
@@ -106,21 +106,21 @@ def self.detect(post)
           },
         )&.source_language_code
 
-      assign_lang_custom_field(post, detected_lang)
+      assign_lang_custom_field(topic_or_post, detected_lang)
     end
 
-    def self.translate(post)
-      from_custom_fields(post) do
+    def self.translate(topic_or_post)
+      from_custom_fields(topic_or_post) do
         result =
           client.translate_text(
             {
-              text: post.cooked.truncate(MAXLENGTH, omission: nil),
+              text: get_text(topic_or_post).truncate(MAXLENGTH, omission: nil),
               source_language_code: "auto",
               target_language_code: SUPPORTED_LANG_MAPPING[I18n.locale],
             },
           )
 
-        detected_lang = assign_lang_custom_field(post, result.source_language_code)
+        detected_lang = assign_lang_custom_field(topic_or_post, result.source_language_code)
 
         [detected_lang, result.translated_text]
       end

services/discourse_translator/base.rb

@@ -31,22 +31,31 @@ def self.access_token
       raise "Not Implemented"
     end
 
-    def self.from_custom_fields(post)
-      post_translated_custom_field =
-        post.custom_fields[DiscourseTranslator::TRANSLATED_CUSTOM_FIELD] || {}
-      translated_text = post_translated_custom_field[I18n.locale]
+    def self.from_custom_fields(topic_or_post)
+      translated_custom_field =
+        topic_or_post.custom_fields[DiscourseTranslator::TRANSLATED_CUSTOM_FIELD] || {}
+      translated_text = translated_custom_field[I18n.locale]
 
       if translated_text.nil?
         translated_text = yield
 
-        post.custom_fields[
+        topic_or_post.custom_fields[
           DiscourseTranslator::TRANSLATED_CUSTOM_FIELD
-        ] = post_translated_custom_field.merge(I18n.locale => translated_text)
+        ] = translated_custom_field.merge(I18n.locale => translated_text)
 
-        post.save!
+        topic_or_post.save!
       end
 
       translated_text
     end
+
+    def self.get_text(topic_or_post)
+      case topic_or_post.class.name
+      when "Post"
+        text = topic_or_post.cooked
+      when "Topic"
+        topic_or_post.title
+      end
+    end
   end
 end

services/discourse_translator/google.rb

@@ -74,10 +74,10 @@ def self.access_token
         (raise TranslatorError.new("NotFound: Google Api Key not set."))
     end
 
-    def self.detect(post)
-      post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= result(
+    def self.detect(topic_or_post)
+      topic_or_post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= result(
         DETECT_URI,
-        q: post.cooked.truncate(MAXLENGTH, omission: nil),
+        q: get_text(topic_or_post).truncate(MAXLENGTH, omission: nil),
       )[
         "detections"
       ][
@@ -92,17 +92,17 @@ def self.translate_supported?(source, target)
       res["languages"].any? { |obj| obj["language"] == source }
     end
 
-    def self.translate(post)
-      detected_lang = detect(post)
+    def self.translate(topic_or_post)
+      detected_lang = detect(topic_or_post)
 
       raise I18n.t("translator.failed") unless translate_supported?(detected_lang, I18n.locale)
 
       translated_text =
-        from_custom_fields(post) do
+        from_custom_fields(topic_or_post) do
           res =
             result(
               TRANSLATE_URI,
-              q: post.cooked.truncate(MAXLENGTH, omission: nil),
+              q: get_text(topic_or_post).truncate(MAXLENGTH, omission: nil),
               source: detected_lang,
               target: SUPPORTED_LANG_MAPPING[I18n.locale],
             )

services/discourse_translator/libretranslate.rb

@@ -80,21 +80,23 @@ def self.access_token
       SiteSetting.translator_libretranslate_api_key
     end
 
-    def self.detect(post)
+    def self.detect(topic_or_post)
       res =
         result(
           detect_uri,
           q:
             ActionController::Base
               .helpers
-              .strip_tags(post.cooked)
+              .strip_tags(get_text(topic_or_post))
               .truncate(MAXLENGTH, omission: nil),
         )
 
       if !res.empty?
-        post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= res[0]["language"]
+        topic_or_post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= res[0][
+          "language"
+        ]
       else
-        post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= "en"
+        topic_or_post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= "en"
       end
     end
 
@@ -104,17 +106,17 @@ def self.translate_supported?(source, target)
       res.any? { |obj| obj["code"] == source } && res.any? { |obj| obj["code"] == lang }
     end
 
-    def self.translate(post)
-      detected_lang = detect(post)
+    def self.translate(topic_or_post)
+      detected_lang = detect(topic_or_post)
 
       raise I18n.t("translator.failed") unless translate_supported?(detected_lang, I18n.locale)
 
       translated_text =
-        from_custom_fields(post) do
+        from_custom_fields(topic_or_post) do
           res =
             result(
               translate_uri,
-              q: post.cooked.truncate(MAXLENGTH, omission: nil),
+              q: get_text(topic_or_post).truncate(MAXLENGTH, omission: nil),
               source: detected_lang,
               target: SUPPORTED_LANG_MAPPING[I18n.locale],
               format: "html",

services/discourse_translator/microsoft.rb

@@ -93,9 +93,9 @@ def self.access_token_key
       "microsoft-translator"
     end
 
-    def self.detect(post)
-      post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= begin
-        text = post.raw.truncate(LENGTH_LIMIT, omission: nil)
+    def self.detect(topic_or_post)
+      topic_or_post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= begin
+        text = get_text(topic_or_post).truncate(LENGTH_LIMIT, omission: nil)
 
         body = [{ "Text" => text }].to_json
 
@@ -108,21 +108,23 @@ def self.detect(post)
       end
     end
 
-    def self.translate(post)
-      detected_lang = detect(post)
+    def self.translate(topic_or_post)
+      detected_lang = detect(topic_or_post)
 
       if !SUPPORTED_LANG_MAPPING.keys.include?(detected_lang.to_sym) &&
            !SUPPORTED_LANG_MAPPING.values.include?(detected_lang.to_s)
         raise TranslatorError.new(I18n.t("translator.failed"))
       end
 
-      raise TranslatorError.new(I18n.t("translator.too_long")) if post.cooked.length > LENGTH_LIMIT
+      if get_text(topic_or_post).length > LENGTH_LIMIT
+        raise TranslatorError.new(I18n.t("translator.too_long"))
+      end
 
       translated_text =
-        from_custom_fields(post) do
+        from_custom_fields(topic_or_post) do
           query = default_query.merge("from" => detected_lang, "to" => locale, "textType" => "html")
 
-          body = [{ "Text" => post.cooked }].to_json
+          body = [{ "Text" => get_text(topic_or_post) }].to_json
 
           uri = URI(translate_endpoint)
           uri.query = URI.encode_www_form(query)

services/discourse_translator/yandex.rb

@@ -123,9 +123,9 @@ def self.access_token
         (raise TranslatorError.new("NotFound: Yandex API Key not set."))
     end
 
-    def self.detect(post)
-      post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= begin
-        query = default_query.merge("text" => post.raw)
+    def self.detect(topic_or_post)
+      topic_or_post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= begin
+        query = default_query.merge("text" => get_text(topic_or_post))
 
         uri = URI(DETECT_URI)
         uri.query = URI.encode_www_form(query)
@@ -136,20 +136,20 @@ def self.detect(post)
       end
     end
 
-    def self.translate(post)
-      detected_lang = detect(post)
+    def self.translate(topic_or_post)
+      detected_lang = detect(topic_or_post)
 
       if !SUPPORTED_LANG_MAPPING.keys.include?(detected_lang.to_sym) &&
            !SUPPORTED_LANG_MAPPING.values.include?(detected_lang.to_s)
         raise TranslatorError.new(I18n.t("translator.failed"))
       end
 
       translated_text =
-        from_custom_fields(post) do
+        from_custom_fields(topic_or_post) do
           query =
             default_query.merge(
               "lang" => "#{detected_lang}-#{locale}",
-              "text" => post.cooked,
+              "text" => get_text(topic_or_post),
               "format" => "html",
             )
 

spec/controllers/translator_controller_spec.rb

@@ -16,11 +16,16 @@
   shared_examples "translation_successful" do
     it "returns the translated text" do
       DiscourseTranslator::Microsoft.expects(:translate).with(reply).returns(%w[ja ニャン猫])
+      if reply.is_first_post?
+        DiscourseTranslator::Microsoft.expects(:translate).with(reply.topic).returns(%w[ja タイトル])
+      end
 
       post :translate, params: { post_id: reply.id }, format: :json
 
       expect(response).to have_http_status(:ok)
-      expect(response.body).to eq({ translation: "ニャン猫", detected_lang: "ja" }.to_json)
+      expect(response.body).to eq(
+        { translation: "ニャン猫", detected_lang: "ja", title_translation: "タイトル" }.to_json,
+      )
     end
   end
 

spec/models/topic_spec.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe Topic do
+  describe "translator custom fields" do
+    fab!(:topic) do
+      Fabricate(
+        :topic,
+        title: "this is a sample title",
+        custom_fields: {
+          ::DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD => "en",
+          ::DiscourseTranslator::TRANSLATED_CUSTOM_FIELD => {
+            "en" => "lol",
+          },
+        },
+      )
+    end
+
+    before { SiteSetting.translator_enabled = true }
+
+    after { SiteSetting.translator_enabled = false }
+
+    it "should reset custom fields when topic title has been updated" do
+      topic.update!(title: "this is an updated title")
+
+      expect(topic.custom_fields[::DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD]).to be_nil
+
+      expect(topic.custom_fields[::DiscourseTranslator::TRANSLATED_CUSTOM_FIELD]).to be_nil
+    end
+  end
+end