Add user content translations with configurable backends (#19218)

app/services/translate_status_service.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class TranslateStatusService < BaseService
+  CACHE_TTL = 1.day.freeze
+
+  def call(status, target_language)
+    raise Mastodon::NotPermittedError unless status.public_visibility? || status.unlisted_visibility?
+
+    @status = status
+    @target_language = target_language
+
+    Rails.cache.fetch("translations/#{@status.language}/#{@target_language}/#{content_hash}", expires_in: CACHE_TTL) { translation_backend.translate(@status.text, @status.language, @target_language) }
+  end
+
+  private
+
+  def translation_backend
+    TranslationService.configured
+  end
+
+  def content_hash
+    Digest::SHA256.base64digest(@status.text)
+  end
+end