FIX: Broken LibreTranslate support

services/discourse_translator/libretranslate.rb

@@ -4,14 +4,9 @@
 require "json"
 
 module DiscourseTranslator
-  class Google < Base
-    TRANSLATE_URI = "https://www.googleapis.com/language/translate/v2".freeze
-    DETECT_URI = "https://www.googleapis.com/language/translate/v2/detect".freeze
-    SUPPORT_URI = "https://www.googleapis.com/language/translate/v2/languages".freeze
+  class LibreTranslate < Base
     MAXLENGTH = 5000
 
-    # Hash which maps Discourse's locale code to Google Translate's locale code found in
-    # https://cloud.google.com/translate/docs/languages
     SUPPORTED_LANG_MAPPING = {
       en: "en",
       en_GB: "en",
@@ -55,8 +50,8 @@ class Google < Base
       th: "th",
       uk: "uk",
       uz: "uz",
-      zh_CN: "zh-CN",
-      zh_TW: "zh-TW",
+      zh_CN: "zh",
+      zh_TW: "zh",
       tr_TR: "tr",
       pt_BR: "pt",
       pl_PL: "pl",
@@ -65,31 +60,48 @@ class Google < Base
       fa_IR: "fa",
     }
 
+    def self.translate_uri
+      SiteSetting.translator_libretranslate_endpoint + "/translate"
+    end
+
+    def self.detect_uri
+      SiteSetting.translator_libretranslate_endpoint + "/detect"
+    end
+
+    def self.support_uri
+      SiteSetting.translator_libretranslate_endpoint + "/languages"
+    end
+
     def self.access_token_key
-      "google-translator"
+      "libretranslate-translator"
     end
 
     def self.access_token
-      SiteSetting.translator_google_api_key ||
-        (raise TranslatorError.new("NotFound: Google Api Key not set."))
+      SiteSetting.translator_libretranslate_api_key
     end
 
     def self.detect(post)
-      post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= result(
-        DETECT_URI,
-        q: post.cooked.truncate(MAXLENGTH, omission: nil),
-      )[
-        "detections"
-      ][
-        0
-      ].max { |a, b| a.confidence <=> b.confidence }[
-        "language"
-      ]
+      res =
+        result(
+          detect_uri,
+          q:
+            ActionController::Base
+              .helpers
+              .strip_tags(post.cooked)
+              .truncate(MAXLENGTH, omission: nil),
+        )
+
+      if !res.empty?
+        post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= res[0]["language"]
+      else
+        post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= "en"
+      end
     end
 
     def self.translate_supported?(source, target)
-      res = result(SUPPORT_URI, target: SUPPORTED_LANG_MAPPING[target])
-      res["languages"].any? { |obj| obj["language"] == source }
+      lang = SUPPORTED_LANG_MAPPING[target]
+      res = get(support_uri)
+      res.any? { |obj| obj["code"] == source } && res.any? { |obj| obj["code"] == lang }
     end
 
     def self.translate(post)
@@ -101,21 +113,39 @@ def self.translate(post)
         from_custom_fields(post) do
           res =
             result(
-              TRANSLATE_URI,
+              translate_uri,
               q: post.cooked.truncate(MAXLENGTH, omission: nil),
               source: detected_lang,
               target: SUPPORTED_LANG_MAPPING[I18n.locale],
+              format: "html",
             )
-          res["translations"][0]["translatedText"]
+          res["translatedText"]
         end
 
       [detected_lang, translated_text]
     end
 
-    def self.result(url, body)
-      body[:key] = access_token
+    def self.get(url)
+      begin
+        response = Excon.get(url)
+        body = JSON.parse(response.body)
+        status = response.status
+      rescue JSON::ParserError, Excon::Error::Socket, Excon::Error::Timeout
+        body = I18n.t("translator.not_available")
+        status = 500
+      end
+
+      if status != 200
+        raise TranslatorError.new(body || response.inspect)
+      else
+        body
+      end
+    end
 
+    def self.result(url, body)
       begin
+        body[:api_key] = access_token
+
         response =
           Excon.post(
             url,
@@ -135,7 +165,7 @@ def self.result(url, body)
       if status != 200
         raise TranslatorError.new(body || response.inspect)
       else
-        body["data"]
+        body
       end
     end
   end

spec/services/libretranslate_spec.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe DiscourseTranslator::LibreTranslate do
+  let(:mock_response) { Struct.new(:status, :body) }
+
+  describe ".access_token" do
+    describe "when set" do
+      api_key = "12345"
+      before { SiteSetting.translator_libretranslate_api_key = api_key }
+      it "should return back translator_libretranslate_api_key" do
+        expect(described_class.access_token).to eq(api_key)
+      end
+    end
+  end
+
+  describe ".translate_supported?" do
+    it "should equate source language to target" do
+      SiteSetting.translator_libretranslate_endpoint = "http://localhost:5000"
+      source = "en"
+      target = :fr
+
+      data = [{ code: "en" }, { code: "fr" }]
+
+      Excon.expects(:get).returns(mock_response.new(200, data.to_json))
+      expect(described_class.translate_supported?(source, target)).to be true
+    end
+  end
+
+  describe ".translate" do
+    let(:post) { Fabricate(:post) }
+
+    before { SiteSetting.translator_libretranslate_endpoint = "http://localhost:5000" }
+
+    it "raises an error on failure" do
+      described_class.expects(:access_token).returns("12345")
+      described_class.expects(:detect).returns("en")
+
+      Excon.expects(:post).returns(
+        mock_response.new(
+          400,
+          {
+            error: "something went wrong",
+            error_description: "you passed in a wrong param",
+          }.to_json,
+        ),
+      )
+
+      expect { described_class.translate(post) }.to raise_error DiscourseTranslator::TranslatorError
+    end
+
+    it "raises an error when the response is not JSON" do
+      described_class.expects(:access_token).returns("12345")
+      described_class.expects(:detect).returns("en")
+
+      Excon.expects(:post).returns(mock_response.new(413, "<html><body>some html</body></html>"))
+
+      expect { described_class.translate(post) }.to raise_error DiscourseTranslator::TranslatorError
+    end
+  end
+end