Only offer translation for supported languages (#23879)

app/javascript/mastodon/components/status_content.jsx

@@ -6,7 +6,7 @@ import { Link } from 'react-router-dom';
 import classnames from 'classnames';
 import PollContainer from 'mastodon/containers/poll_container';
 import Icon from 'mastodon/components/icon';
-import { autoPlayGif, languages as preloadedLanguages, translationEnabled } from 'mastodon/initial_state';
+import { autoPlayGif, languages as preloadedLanguages } from 'mastodon/initial_state';
 
 const MAX_HEIGHT = 706; // 22px * 32 (+ 2px padding at the top)
 
@@ -220,7 +220,7 @@ class StatusContent extends React.PureComponent {
 
     const hidden = this.props.onExpandedToggle ? !this.props.expanded : this.state.hidden;
     const renderReadMore = this.props.onClick && status.get('collapsed');
-    const renderTranslate = translationEnabled && this.context.identity.signedIn && this.props.onTranslate && ['public', 'unlisted'].includes(status.get('visibility')) && status.get('contentHtml').length > 0 && status.get('language') !== null && intl.locale !== status.get('language');
+    const renderTranslate = this.props.onTranslate && status.get('translatable');
 
     const content = { __html: status.get('translation') ? status.getIn(['translation', 'content']) : status.get('contentHtml') };
     const spoilerContent = { __html: status.get('spoilerHtml') };

app/javascript/mastodon/initial_state.js

@@ -80,7 +80,6 @@
  * @property {boolean} use_blurhash
  * @property {boolean=} use_pending_items
  * @property {string} version
- * @property {boolean} translation_enabled
  */
 
 /**
@@ -132,7 +131,6 @@ export const unfollowModal = getMeta('unfollow_modal');
 export const useBlurhash = getMeta('use_blurhash');
 export const usePendingItems = getMeta('use_pending_items');
 export const version = getMeta('version');
-export const translationEnabled = getMeta('translation_enabled');
 export const languages = initialState?.languages;
 export const statusPageUrl = getMeta('status_page_url');
 

app/lib/translation_service.rb

@@ -21,6 +21,10 @@ class TranslationService
     ENV['DEEPL_API_KEY'].present? || ENV['LIBRE_TRANSLATE_ENDPOINT'].present?
   end
 
+  def supported?(_source_language, _target_language)
+    false
+  end
+
   def translate(_text, _source_language, _target_language)
     raise NotImplementedError
   end

app/lib/translation_service/deepl.rb

@@ -11,33 +11,53 @@ class TranslationService::DeepL < TranslationService
   end
 
   def translate(text, source_language, target_language)
-    request(text, source_language, target_language).perform do |res|
+    form = { text: text, source_lang: source_language&.upcase, target_lang: target_language, tag_handling: 'html' }
+    request(:post, '/v2/translate', form: form) do |res|
+      transform_response(res.body_with_limit)
+    end
+  end
+
+  def supported?(source_language, target_language)
+    source_language.in?(languages('source')) && target_language.in?(languages('target'))
+  end
+
+  private
+
+  def languages(type)
+    Rails.cache.fetch("translation_service/deepl/languages/#{type}", expires_in: 7.days, race_condition_ttl: 1.minute) do
+      request(:get, "/v2/languages?type=#{type}") do |res|
+        # In DeepL, EN and PT are deprecated in favor of EN-GB/EN-US and PT-BR/PT-PT, so
+        # they are supported but not returned by the API.
+        extra = type == 'source' ? [nil] : %w(en pt)
+        languages = Oj.load(res.body_with_limit).map { |language| language['language'].downcase }
+
+        languages + extra
+      end
+    end
+  end
+
+  def request(verb, path, **options)
+    req = Request.new(verb, "#{base_url}#{path}", **options)
+    req.add_headers(Authorization: "DeepL-Auth-Key #{@api_key}")
+    req.perform do |res|
       case res.code
       when 429
         raise TooManyRequestsError
       when 456
         raise QuotaExceededError
       when 200...300
-        transform_response(res.body_with_limit)
+        yield res
       else
         raise UnexpectedResponseError
       end
     end
   end
 
-  private
-
-  def request(text, source_language, target_language)
-    req = Request.new(:post, endpoint_url, form: { text: text, source_lang: source_language&.upcase, target_lang: target_language, tag_handling: 'html' })
-    req.add_headers(Authorization: "DeepL-Auth-Key #{@api_key}")
-    req
-  end
-
-  def endpoint_url
+  def base_url
     if @plan == 'free'
-      'https://api-free.deepl.com/v2/translate'
+      'https://api-free.deepl.com'
     else
-      'https://api.deepl.com/v2/translate'
+      'https://api.deepl.com'
     end
   end
 

app/lib/translation_service/libre_translate.rb

@@ -9,29 +9,45 @@ class TranslationService::LibreTranslate < TranslationService
   end
 
   def translate(text, source_language, target_language)
-    request(text, source_language, target_language).perform do |res|
+    body = Oj.dump(q: text, source: source_language.presence || 'auto', target: target_language, format: 'html', api_key: @api_key)
+    request(:post, '/translate', body: body) do |res|
+      transform_response(res.body_with_limit, source_language)
+    end
+  end
+
+  def supported?(source_language, target_language)
+    languages.key?(source_language) && languages[source_language].include?(target_language)
+  end
+
+  private
+
+  def languages
+    Rails.cache.fetch('translation_service/libre_translate/languages', expires_in: 7.days, race_condition_ttl: 1.minute) do
+      request(:get, '/languages') do |res|
+        languages = Oj.load(res.body_with_limit).to_h { |language| [language['code'], language['targets']] }
+        languages[nil] = languages.values.flatten.uniq
+        languages
+      end
+    end
+  end
+
+  def request(verb, path, **options)
+    req = Request.new(verb, "#{@base_url}#{path}", allow_local: true, **options)
+    req.add_headers('Content-Type': 'application/json')
+    req.perform do |res|
       case res.code
       when 429
         raise TooManyRequestsError
       when 403
         raise QuotaExceededError
       when 200...300
-        transform_response(res.body_with_limit, source_language)
+        yield res
       else
         raise UnexpectedResponseError
       end
     end
   end
 
-  private
-
-  def request(text, source_language, target_language)
-    body = Oj.dump(q: text, source: source_language.presence || 'auto', target: target_language, format: 'html', api_key: @api_key)
-    req = Request.new(:post, "#{@base_url}/translate", body: body, allow_local: true)
-    req.add_headers('Content-Type': 'application/json')
-    req
-  end
-
   def transform_response(str, source_language)
     json = Oj.load(str, mode: :strict)
 

app/models/status.rb

@@ -232,6 +232,16 @@ class Status < ApplicationRecord
     public_visibility? || unlisted_visibility?
   end
 
+  def translatable?
+    translate_target_locale = I18n.locale.to_s.split(/[_-]/).first
+
+    distributable? &&
+      content.present? &&
+      language != translate_target_locale &&
+      TranslationService.configured? &&
+      TranslationService.configured.supported?(language, translate_target_locale)
+  end
+
   alias sign? distributable?
 
   def with_media?

app/serializers/initial_state_serializer.rb

@@ -30,7 +30,6 @@ class InitialStateSerializer < ActiveModel::Serializer
       timeline_preview: Setting.timeline_preview,
       activity_api_enabled: Setting.activity_api_enabled,
       single_user_mode: Rails.configuration.x.single_user_mode,
-      translation_enabled: TranslationService.configured?,
       trends_as_landing_page: Setting.trends_as_landing_page,
       status_page_url: Setting.status_page_url,
     }

app/serializers/rest/status_serializer.rb

@@ -4,7 +4,7 @@ class REST::StatusSerializer < ActiveModel::Serializer
   include FormattingHelper
 
   attributes :id, :created_at, :in_reply_to_id, :in_reply_to_account_id,
-             :sensitive, :spoiler_text, :visibility, :language,
+             :sensitive, :spoiler_text, :visibility, :language, :translatable,
              :uri, :url, :replies_count, :reblogs_count,
              :favourites_count, :edited_at
 
@@ -50,6 +50,10 @@ class REST::StatusSerializer < ActiveModel::Serializer
     object.account.user_shows_application? || (current_user? && current_user.account_id == object.account_id)
   end
 
+  def translatable
+    current_user? && object.translatable?
+  end
+
   def visibility
     # This visibility is masked behind "private"
     # to avoid API changes because there are no

app/services/translate_status_service.rb

@@ -6,7 +6,7 @@ class TranslateStatusService < BaseService
   include FormattingHelper
 
   def call(status, target_language)
-    raise Mastodon::NotPermittedError unless status.public_visibility? || status.unlisted_visibility?
+    raise Mastodon::NotPermittedError unless status.translatable?
 
     @status = status
     @content = status_content_format(@status)