Add support for translations

src/invidious.cr

@@ -88,6 +88,15 @@ REDDIT_URL      = URI.parse("https://www.reddit.com")
 LOGIN_URL       = URI.parse("https://accounts.google.com")
 TEXTCAPTCHA_URL = URI.parse("http://textcaptcha.com/omarroth@hotmail.com.json")
 
+LOCALES = {
+  "ar"    => load_locale("ar"),
+  "de"    => load_locale("de"),
+  "en-US" => load_locale("en-US"),
+  "nl"    => load_locale("nl"),
+  "pl"    => load_locale("pl"),
+  "ru"    => load_locale("ru"),
+}
+
 crawl_threads.times do
   spawn do
     crawl_videos(PG_DB)
@@ -147,6 +156,7 @@ before_all do |env|
         env.set "challenge", challenge
         env.set "token", token
 
+        locale = user.preferences.locale
         env.set "user", user
         env.set "sid", sid
       end
@@ -158,6 +168,7 @@ before_all do |env|
         env.set "challenge", challenge
         env.set "token", token
 
+        locale = user.preferences.locale
         env.set "user", user
         env.set "sid", sid
       rescue ex
@@ -165,6 +176,10 @@ before_all do |env|
     end
   end
 
+  locale = env.params.query["hl"]? || locale
+  locale ||= "en-US"
+  env.set "locale", locale
+
   current_page = env.request.path
   if env.request.query
     query = HTTP::Params.parse(env.request.query.not_nil!)
@@ -180,7 +195,9 @@ before_all do |env|
 end
 
 get "/" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
   user = env.get? "user"
+
   if user
     user = user.as(User)
     if user.preferences.redirect_feed
@@ -192,12 +209,14 @@ get "/" do |env|
 end
 
 get "/licenses" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
   rendered "licenses"
 end
 
 # Videos
 
 get "/:id" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
   id = env.params.url["id"]
 
   if md = id.match(/[a-zA-Z0-9_-]{11}/)
@@ -219,6 +238,8 @@ get "/:id" do |env|
 end
 
 get "/watch" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   if env.params.query.to_s.includes?("%20") || env.params.query.to_s.includes?("+")
     url = "/watch?" + env.params.query.to_s.gsub("%20", "").delete("+")
     next env.redirect url
@@ -287,11 +308,11 @@ get "/watch" do |env|
 
       if source == "youtube"
         begin
-          comment_html = JSON.parse(fetch_youtube_comments(id, "", proxies, "html"))["contentHtml"]
+          comment_html = JSON.parse(fetch_youtube_comments(id, "", proxies, "html", locale))["contentHtml"]
         rescue ex
           if preferences.comments[1] == "reddit"
             comments, reddit_thread = fetch_reddit_comments(id)
-            comment_html = template_reddit_comments(comments)
+            comment_html = template_reddit_comments(comments, locale)
 
             comment_html = fill_links(comment_html, "https", "www.reddit.com")
             comment_html = replace_links(comment_html)
@@ -300,18 +321,18 @@ get "/watch" do |env|
       elsif source == "reddit"
         begin
           comments, reddit_thread = fetch_reddit_comments(id)
-          comment_html = template_reddit_comments(comments)
+          comment_html = template_reddit_comments(comments, locale)
 
           comment_html = fill_links(comment_html, "https", "www.reddit.com")
           comment_html = replace_links(comment_html)
         rescue ex
           if preferences.comments[1] == "youtube"
-            comment_html = JSON.parse(fetch_youtube_comments(id, "", proxies, "html"))["contentHtml"]
+            comment_html = JSON.parse(fetch_youtube_comments(id, "", proxies, "html", locale))["contentHtml"]
           end
         end
       end
     else
-      comment_html = JSON.parse(fetch_youtube_comments(id, "", proxies, "html"))["contentHtml"]
+      comment_html = JSON.parse(fetch_youtube_comments(id, "", proxies, "html", locale))["contentHtml"]
     end
 
     comment_html ||= ""
@@ -383,6 +404,7 @@ get "/watch" do |env|
 end
 
 get "/embed/:id" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
   id = env.params.url["id"]
 
   if id.includes?("%20") || id.includes?("+") || env.params.query.to_s.includes?("%20") || env.params.query.to_s.includes?("+")
@@ -470,6 +492,8 @@ end
 # Playlists
 
 get "/playlist" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   plid = env.params.query["list"]?
   if !plid
     next env.redirect "/"
@@ -483,14 +507,14 @@ get "/playlist" do |env|
   end
 
   begin
-    playlist = fetch_playlist(plid)
+    playlist = fetch_playlist(plid, locale)
   rescue ex
     error_message = ex.message
     next templated "error"
   end
 
   begin
-    videos = fetch_playlist_videos(plid, page, playlist.video_count)
+    videos = fetch_playlist_videos(plid, page, playlist.video_count, locale)
   rescue ex
     videos = [] of PlaylistVideo
   end
@@ -499,6 +523,8 @@ get "/playlist" do |env|
 end
 
 get "/mix" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   rdid = env.params.query["list"]?
   if !rdid
     next env.redirect "/"
@@ -508,7 +534,7 @@ get "/mix" do |env|
   continuation ||= rdid.lchop("RD")
 
   begin
-    mix = fetch_mix(rdid, continuation)
+    mix = fetch_mix(rdid, continuation, locale: locale)
   rescue ex
     error_message = ex.message
     next templated "error"
@@ -520,6 +546,7 @@ end
 # Search
 
 get "/opensearch.xml" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
   env.response.content_type = "application/opensearchdescription+xml"
 
   XML.build(indent: "  ", encoding: "UTF-8") do |xml|
@@ -535,6 +562,8 @@ get "/opensearch.xml" do |env|
 end
 
 get "/results" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   query = env.params.query["search_query"]?
   query ||= env.params.query["q"]?
   query ||= ""
@@ -550,6 +579,8 @@ get "/results" do |env|
 end
 
 get "/search" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   query = env.params.query["search_query"]?
   query ||= env.params.query["q"]?
   query ||= ""
@@ -629,6 +660,8 @@ end
 # Users
 
 get "/login" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   if user
     next env.redirect "/feed/subscriptions"
@@ -668,6 +701,8 @@ end
 
 # See https://github.com/rg3/youtube-dl/blob/master/youtube_dl/extractor/youtube.py#L79
 post "/login" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   referer = get_referer(env, "/feed/subscriptions")
 
   email = env.params.body["email"]?
@@ -754,7 +789,7 @@ post "/login" do |env|
       headers["Cookie"] = URI.unescape(headers["Cookie"])
 
       if challenge_results[0][-1]?.try &.[5] == "INCORRECT_ANSWER_ENTERED"
-        error_message = "Incorrect password"
+        error_message = translate(locale, "Incorrect password")
         next templated "error"
       end
 
@@ -775,7 +810,7 @@ post "/login" do |env|
 
         if tfa[2] == "TWO_STEP_VERIFICATION"
           if tfa[5] == "QUOTA_EXCEEDED"
-            error_message = "Quota exceeded, try again in a few hours"
+            error_message = translate(locale, "Quota exceeded, try again in a few hours")
             next templated "error"
           end
 
@@ -806,7 +841,7 @@ post "/login" do |env|
           challenge_results = JSON.parse(challenge_results)
 
           if challenge_results[0][-1]?.try &.[5] == "INCORRECT_ANSWER_ENTERED"
-            error_message = "Invalid TFA code"
+            error_message = translate(locale, "Invalid TFA code")
             next templated "error"
           end
         end
@@ -845,7 +880,7 @@ post "/login" do |env|
 
       env.redirect referer
     rescue ex
-      error_message = "Login failed. This may be because two-factor authentication is not enabled on your account."
+      error_message = translate(locale, "Login failed. This may be because two-factor authentication is not enabled on your account.")
       next templated "error"
     end
   elsif account_type == "invidious"
@@ -860,10 +895,10 @@ post "/login" do |env|
       token = env.params.body["token"]?
 
       begin
-        validate_response(challenge, token, answer, "sign_in", HMAC_KEY, PG_DB)
+        validate_response(challenge, token, answer, "sign_in", HMAC_KEY, PG_DB, locale)
       rescue ex
-        if ex.message == "Invalid user"
-          error_message = "Invalid answer"
+        if ex.message == translate(locale, "Invalid user")
+          error_message = translate(locale, "Invalid answer")
         else
           error_message = ex.message
         end
@@ -878,16 +913,16 @@ post "/login" do |env|
 
       found_valid_captcha = false
 
-      error_message = "Invalid CAPTCHA"
+      error_message = translate(locale, "Invalid CAPTCHA")
       challenges.each_with_index do |challenge, i|
         begin
           challenge = challenge[1]
           token = tokens[i][1]
-          validate_response(challenge, token, text_answer, "sign_in", HMAC_KEY, PG_DB)
+          validate_response(challenge, token, text_answer, "sign_in", HMAC_KEY, PG_DB, locale)
           found_valid_captcha = true
         rescue ex
-          if ex.message == "Invalid user"
-            error_message = "Invalid answer"
+          if ex.message == translate(locale, "Invalid user")
+            error_message = translate(locale, "Invalid answer")
           else
             error_message = ex.message
           end
@@ -898,7 +933,7 @@ post "/login" do |env|
         next templated "error"
       end
     else
-      error_message = "CAPTCHA is a required field"
+      error_message = translate(locale, "CAPTCHA is a required field")
       next templated "error"
     end
 
@@ -906,12 +941,12 @@ post "/login" do |env|
     action ||= "signin"
 
     if !email
-      error_message = "User ID is a required field"
+      error_message = translate(locale, "User ID is a required field")
       next templated "error"
     end
 
     if !password
-      error_message = "Password is a required field"
+      error_message = translate(locale, "Password is a required field")
       next templated "error"
     end
 
@@ -919,12 +954,12 @@ post "/login" do |env|
       user = PG_DB.query_one?("SELECT * FROM users WHERE LOWER(email) = LOWER($1) AND password IS NOT NULL", email, as: User)
 
       if !user
-        error_message = "Invalid username or password"
+        error_message = translate(locale, "Invalid username or password")
         next templated "error"
       end
 
       if !user.password
-        error_message = "Please sign in using 'Sign in with Google'"
+        error_message = translate(locale, "Please sign in using 'Sign in with Google'")
         next templated "error"
       end
 
@@ -946,24 +981,24 @@ post "/login" do |env|
             secure: secure, http_only: true)
         end
       else
-        error_message = "Invalid username or password"
+        error_message = translate(locale, "Invalid username or password")
         next templated "error"
       end
     elsif action == "register"
       if password.empty?
-        error_message = "Password cannot be empty"
+        error_message = translate(locale, "Password cannot be empty")
         next templated "error"
       end
 
       # See https://security.stackexchange.com/a/39851
       if password.size > 55
-        error_message = "Password cannot be longer than 55 characters"
+        error_message = translate(locale, "Password cannot be longer than 55 characters")
         next templated "error"
       end
 
       user = PG_DB.query_one?("SELECT * FROM users WHERE LOWER(email) = LOWER($1) AND password IS NOT NULL", email, as: User)
       if user
-        error_message = "Please sign in"
+        error_message = translate(locale, "Please sign in")
         next templated "error"
       end
 
@@ -1002,6 +1037,8 @@ post "/login" do |env|
 end
 
 get "/signout" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1012,7 +1049,7 @@ get "/signout" do |env|
     token = env.params.query["token"]?
 
     begin
-      validate_response(challenge, token, user.email, "sign_out", HMAC_KEY, PG_DB)
+      validate_response(challenge, token, user.email, "sign_out", HMAC_KEY, PG_DB, locale)
     rescue ex
       error_message = ex.message
       next templated "error"
@@ -1033,6 +1070,8 @@ get "/signout" do |env|
 end
 
 get "/preferences" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1045,6 +1084,8 @@ get "/preferences" do |env|
 end
 
 post "/preferences" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1093,6 +1134,9 @@ post "/preferences" do |env|
     redirect_feed ||= "off"
     redirect_feed = redirect_feed == "on"
 
+    locale = env.params.body["locale"]?.try &.as(String)
+    locale ||= "en-US"
+
     dark_mode = env.params.body["dark_mode"]?.try &.as(String)
     dark_mode ||= "off"
     dark_mode = dark_mode == "on"
@@ -1131,6 +1175,7 @@ post "/preferences" do |env|
       "captions"           => captions,
       "related_videos"     => related_videos,
       "redirect_feed"      => redirect_feed,
+      "locale"             => locale,
       "dark_mode"          => dark_mode,
       "thin_mode"          => thin_mode,
       "max_results"        => max_results,
@@ -1147,6 +1192,8 @@ post "/preferences" do |env|
 end
 
 get "/toggle_theme" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1167,6 +1214,8 @@ get "/toggle_theme" do |env|
 end
 
 get "/mark_watched" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env, "/feed/subscriptions")
 
@@ -1195,6 +1244,8 @@ get "/mark_watched" do |env|
 end
 
 get "/mark_unwatched" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env, "/feed/history")
 
@@ -1225,6 +1276,8 @@ end
 # /modify_notifications?receive_all_updates=false&receive_no_updates=false
 # will "unding" all subscriptions.
 get "/modify_notifications" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1270,6 +1323,8 @@ get "/modify_notifications" do |env|
 end
 
 get "/subscription_manager" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env, "/")
 
@@ -1351,6 +1406,8 @@ get "/subscription_manager" do |env|
 end
 
 get "/data_control" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1364,6 +1421,8 @@ get "/data_control" do |env|
 end
 
 post "/data_control" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1495,6 +1554,8 @@ post "/data_control" do |env|
 end
 
 get "/subscription_ajax" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1574,6 +1635,8 @@ get "/subscription_ajax" do |env|
 end
 
 get "/delete_account" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1589,6 +1652,8 @@ get "/delete_account" do |env|
 end
 
 post "/delete_account" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1599,7 +1664,7 @@ post "/delete_account" do |env|
     token = env.params.body["token"]?
 
     begin
-      validate_response(challenge, token, user.email, "delete_account", HMAC_KEY, PG_DB)
+      validate_response(challenge, token, user.email, "delete_account", HMAC_KEY, PG_DB, locale)
     rescue ex
       error_message = ex.message
       next templated "error"
@@ -1619,6 +1684,8 @@ post "/delete_account" do |env|
 end
 
 get "/clear_watch_history" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1634,6 +1701,8 @@ get "/clear_watch_history" do |env|
 end
 
 post "/clear_watch_history" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1644,7 +1713,7 @@ post "/clear_watch_history" do |env|
     token = env.params.body["token"]?
 
     begin
-      validate_response(challenge, token, user.email, "clear_watch_history", HMAC_KEY, PG_DB)
+      validate_response(challenge, token, user.email, "clear_watch_history", HMAC_KEY, PG_DB, locale)
     rescue ex
       error_message = ex.message
       next templated "error"
@@ -1659,19 +1728,25 @@ end
 # Feeds
 
 get "/feed/top" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   templated "top"
 end
 
 get "/feed/popular" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   templated "popular"
 end
 
 get "/feed/trending" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   trending_type = env.params.query["type"]?
   region = env.params.query["region"]?
 
   begin
-    trending = fetch_trending(trending_type, proxies, region)
+    trending = fetch_trending(trending_type, proxies, region, locale)
   rescue ex
     error_message = "#{ex.message}"
     next templated "error"
@@ -1681,6 +1756,8 @@ get "/feed/trending" do |env|
 end
 
 get "/feed/subscriptions" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1814,6 +1891,8 @@ get "/feed/subscriptions" do |env|
 end
 
 get "/feed/history" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   referer = get_referer(env)
 
@@ -1837,11 +1916,13 @@ get "/feed/history" do |env|
 end
 
 get "/feed/channel/:ucid" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   env.response.content_type = "text/xml"
   ucid = env.params.url["ucid"]
 
   begin
-    author, ucid, auto_generated = get_about_info(ucid)
+    author, ucid, auto_generated = get_about_info(ucid, locale)
   rescue ex
     error_message = ex.message
     halt env, status_code: 500, response: error_message
@@ -1906,6 +1987,8 @@ get "/feed/channel/:ucid" do |env|
 end
 
 get "/feed/private" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   token = env.params.query["token"]?
 
   if !token
@@ -1978,7 +2061,7 @@ get "/feed/private" do |env|
       "xml:lang": "en-US") do
       xml.element("link", "type": "text/html", rel: "alternate", href: "#{host_url}/feed/subscriptions")
       xml.element("link", "type": "application/atom+xml", rel: "self", href: "#{host_url}#{path}?#{query}")
-      xml.element("title") { xml.text "Invidious Private Feed for #{user.email}" }
+      xml.element("title") { xml.text translate(locale, "Invidious Private Feed for `x`", user.email) }
 
       videos.each do |video|
         xml.element("entry") do
@@ -2011,6 +2094,8 @@ get "/feed/private" do |env|
 end
 
 get "/feed/playlist/:plid" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   plid = env.params.url["plid"]
 
   host_url = make_host_url(Kemal.config.ssl || CONFIG.https_only, env.request.headers["Host"]?)
@@ -2047,6 +2132,8 @@ end
 # YouTube appears to let users set a "brand" URL that
 # is different from their username, so we convert that here
 get "/c/:user" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   client = make_client(YT_URL)
   user = env.params.url["user"]
 
@@ -2072,6 +2159,8 @@ get "/user/:user/videos" do |env|
 end
 
 get "/channel/:ucid" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   user = env.get? "user"
   if user
     user = user.as(User)
@@ -2088,7 +2177,7 @@ get "/channel/:ucid" do |env|
   sort_by ||= "newest"
 
   begin
-    author, ucid, auto_generated, sub_count = get_about_info(ucid)
+    author, ucid, auto_generated, sub_count = get_about_info(ucid, locale)
   rescue ex
     error_message = ex.message
     next templated "error"
@@ -2108,6 +2197,8 @@ get "/channel/:ucid" do |env|
 end
 
 get "/channel/:ucid/videos" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   ucid = env.params.url["ucid"]
   params = env.request.query
 
@@ -2123,6 +2214,8 @@ end
 # API Endpoints
 
 get "/api/v1/captions/:id" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   env.response.content_type = "application/json"
 
   id = env.params.url["id"]
@@ -2222,6 +2315,8 @@ get "/api/v1/captions/:id" do |env|
 end
 
 get "/api/v1/comments/:id" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   env.response.content_type = "application/json"
 
   id = env.params.url["id"]
@@ -2237,7 +2332,7 @@ get "/api/v1/comments/:id" do |env|
 
   if source == "youtube"
     begin
-      comments = fetch_youtube_comments(id, continuation, proxies, format)
+      comments = fetch_youtube_comments(id, continuation, proxies, format, locale)
     rescue ex
       error_message = {"error" => ex.message}.to_json
       halt env, status_code: 500, response: error_message
@@ -2247,7 +2342,7 @@ get "/api/v1/comments/:id" do |env|
   elsif source == "reddit"
     begin
       comments, reddit_thread = fetch_reddit_comments(id)
-      content_html = template_reddit_comments(comments)
+      content_html = template_reddit_comments(comments, locale)
 
       content_html = fill_links(content_html, "https", "www.reddit.com")
       content_html = replace_links(content_html)
@@ -2276,6 +2371,8 @@ get "/api/v1/comments/:id" do |env|
 end
 
 get "/api/v1/insights/:id" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   id = env.params.url["id"]
   env.response.content_type = "application/json"
 
@@ -2356,6 +2453,8 @@ get "/api/v1/insights/:id" do |env|
 end
 
 get "/api/v1/videos/:id" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   env.response.content_type = "application/json"
 
   id = env.params.url["id"]
@@ -2388,7 +2487,7 @@ get "/api/v1/videos/:id" do |env|
       json.field "description", description
       json.field "descriptionHtml", video.description
       json.field "published", video.published.to_unix
-      json.field "publishedText", "#{recode_date(video.published)} ago"
+      json.field "publishedText", translate(locale, "`x` ago", recode_date(video.published))
       json.field "keywords", video.keywords
 
       json.field "viewCount", video.views
@@ -2559,11 +2658,13 @@ get "/api/v1/videos/:id" do |env|
 end
 
 get "/api/v1/trending" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   region = env.params.query["region"]?
   trending_type = env.params.query["type"]?
 
   begin
-    trending = fetch_trending(trending_type, proxies, region)
+    trending = fetch_trending(trending_type, proxies, region, locale)
   rescue ex
     error_message = {"error" => ex.message}.to_json
     halt env, status_code: 500, response: error_message
@@ -2587,7 +2688,7 @@ get "/api/v1/trending" do |env|
           json.field "authorUrl", "/channel/#{video.ucid}"
 
           json.field "published", video.published.to_unix
-          json.field "publishedText", "#{recode_date(video.published)} ago"
+          json.field "publishedText", translate(locale, "`x` ago", recode_date(video.published))
           json.field "description", video.description
           json.field "descriptionHtml", video.description_html
           json.field "liveNow", video.live_now
@@ -2603,6 +2704,8 @@ get "/api/v1/trending" do |env|
 end
 
 get "/api/v1/popular" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   videos = JSON.build do |json|
     json.array do
       popular_videos.each do |video|
@@ -2619,7 +2722,7 @@ get "/api/v1/popular" do |env|
           json.field "authorId", video.ucid
           json.field "authorUrl", "/channel/#{video.ucid}"
           json.field "published", video.published.to_unix
-          json.field "publishedText", "#{recode_date(video.published)} ago"
+          json.field "publishedText", translate(locale, "`x` ago", recode_date(video.published))
         end
       end
     end
@@ -2630,6 +2733,8 @@ get "/api/v1/popular" do |env|
 end
 
 get "/api/v1/top" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   videos = JSON.build do |json|
     json.array do
       top_videos.each do |video|
@@ -2647,7 +2752,7 @@ get "/api/v1/top" do |env|
           json.field "authorId", video.ucid
           json.field "authorUrl", "/channel/#{video.ucid}"
           json.field "published", video.published.to_unix
-          json.field "publishedText", "#{recode_date(video.published)} ago"
+          json.field "publishedText", translate(locale, "`x` ago", recode_date(video.published))
 
           description = video.description.gsub("<br>", "\n")
           description = description.gsub("<br/>", "\n")
@@ -2664,6 +2769,8 @@ get "/api/v1/top" do |env|
 end
 
 get "/api/v1/channels/:ucid" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   env.response.content_type = "application/json"
 
   ucid = env.params.url["ucid"]
@@ -2671,7 +2778,7 @@ get "/api/v1/channels/:ucid" do |env|
   sort_by ||= "newest"
 
   begin
-    author, ucid, auto_generated = get_about_info(ucid)
+    author, ucid, auto_generated = get_about_info(ucid, locale)
   rescue ex
     error_message = {"error" => ex.message}.to_json
     halt env, status_code: 500, response: error_message
@@ -2817,7 +2924,7 @@ get "/api/v1/channels/:ucid" do |env|
 
               json.field "viewCount", video.views
               json.field "published", video.published.to_unix
-              json.field "publishedText", "#{recode_date(video.published)} ago"
+              json.field "publishedText", translate(locale, "`x` ago", recode_date(video.published))
               json.field "lengthSeconds", video.length_seconds
               json.field "liveNow", video.live_now
               json.field "paid", video.paid
@@ -2860,6 +2967,8 @@ end
 
 ["/api/v1/channels/:ucid/videos", "/api/v1/channels/videos/:ucid"].each do |route|
   get route do |env|
+    locale = LOCALES[env.get("locale").as(String)]?
+
     env.response.content_type = "application/json"
 
     ucid = env.params.url["ucid"]
@@ -2869,7 +2978,7 @@ end
     sort_by ||= "newest"
 
     begin
-      author, ucid, auto_generated = get_about_info(ucid)
+      author, ucid, auto_generated = get_about_info(ucid, locale)
     rescue ex
       error_message = {"error" => ex.message}.to_json
       halt env, status_code: 500, response: error_message
@@ -2908,7 +3017,7 @@ end
 
             json.field "viewCount", video.views
             json.field "published", video.published.to_unix
-            json.field "publishedText", "#{recode_date(video.published)} ago"
+            json.field "publishedText", translate(locale, "`x` ago", recode_date(video.published))
             json.field "lengthSeconds", video.length_seconds
             json.field "liveNow", video.live_now
             json.field "paid", video.paid
@@ -2923,6 +3032,8 @@ end
 end
 
 get "/api/v1/channels/search/:ucid" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   env.response.content_type = "application/json"
 
   ucid = env.params.url["ucid"]
@@ -2957,7 +3068,7 @@ get "/api/v1/channels/search/:ucid" do |env|
 
             json.field "viewCount", item.views
             json.field "published", item.published.to_unix
-            json.field "publishedText", "#{recode_date(item.published)} ago"
+            json.field "publishedText", translate(locale, "`x` ago", recode_date(item.published))
             json.field "lengthSeconds", item.length_seconds
             json.field "liveNow", item.live_now
             json.field "paid", item.paid
@@ -3021,6 +3132,8 @@ get "/api/v1/channels/search/:ucid" do |env|
 end
 
 get "/api/v1/search" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   env.response.content_type = "application/json"
 
   query = env.params.query["q"]?
@@ -3080,7 +3193,7 @@ get "/api/v1/search" do |env|
 
             json.field "viewCount", item.views
             json.field "published", item.published.to_unix
-            json.field "publishedText", "#{recode_date(item.published)} ago"
+            json.field "publishedText", translate(locale, "`x` ago", recode_date(item.published))
             json.field "lengthSeconds", item.length_seconds
             json.field "liveNow", item.live_now
             json.field "paid", item.paid
@@ -3144,6 +3257,8 @@ get "/api/v1/search" do |env|
 end
 
 get "/api/v1/playlists/:plid" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   env.response.content_type = "application/json"
   plid = env.params.url["plid"]
 
@@ -3160,14 +3275,14 @@ get "/api/v1/playlists/:plid" do |env|
   end
 
   begin
-    playlist = fetch_playlist(plid)
+    playlist = fetch_playlist(plid, locale)
   rescue ex
     error_message = {"error" => "Playlist is empty"}.to_json
     halt env, status_code: 500, response: error_message
   end
 
   begin
-    videos = fetch_playlist_videos(plid, page, playlist.video_count, continuation)
+    videos = fetch_playlist_videos(plid, page, playlist.video_count, continuation, locale)
   rescue ex
     videos = [] of PlaylistVideo
   end
@@ -3241,6 +3356,8 @@ get "/api/v1/playlists/:plid" do |env|
 end
 
 get "/api/v1/mixes/:rdid" do |env|
+  locale = LOCALES[env.get("locale").as(String)]?
+
   env.response.content_type = "application/json"
 
   rdid = env.params.url["rdid"]
@@ -3252,7 +3369,7 @@ get "/api/v1/mixes/:rdid" do |env|
   format ||= "json"
 
   begin
-    mix = fetch_mix(rdid, continuation)
+    mix = fetch_mix(rdid, continuation, locale: locale)
 
     if !rdid.ends_with? continuation
       mix = fetch_mix(rdid, mix.videos[1].id)

src/invidious/channels.cr

@@ -28,7 +28,7 @@ def get_channel(id, db, refresh = true, pull_all_videos = true)
     channel = db.query_one("SELECT * FROM channels WHERE id = $1", id, as: InvidiousChannel)
 
     if refresh && Time.now - channel.updated > 10.minutes
-      channel = fetch_channel(id, client, db, pull_all_videos)
+      channel = fetch_channel(id, client, db, pull_all_videos: pull_all_videos)
       channel_array = channel.to_a
       args = arg_array(channel_array)
 
@@ -36,7 +36,7 @@ def get_channel(id, db, refresh = true, pull_all_videos = true)
         ON CONFLICT (id) DO UPDATE SET author = $2, updated = $3", channel_array)
     end
   else
-    channel = fetch_channel(id, client, db, pull_all_videos)
+    channel = fetch_channel(id, client, db, pull_all_videos: pull_all_videos)
     channel_array = channel.to_a
     args = arg_array(channel_array)
 
@@ -46,13 +46,13 @@ def get_channel(id, db, refresh = true, pull_all_videos = true)
   return channel
 end
 
-def fetch_channel(ucid, client, db, pull_all_videos = true)
+def fetch_channel(ucid, client, db, pull_all_videos = true, locale = nil)
   rss = client.get("/feeds/videos.xml?channel_id=#{ucid}").body
   rss = XML.parse_html(rss)
 
   author = rss.xpath_node(%q(//feed/title))
   if !author
-    raise "Deleted or invalid channel"
+    raise translate(locale, "Deleted or invalid channel")
   end
   author = author.content
 
@@ -223,7 +223,7 @@ def produce_channel_videos_url(ucid, page = 1, auto_generated = nil, sort_by = "
   return url
 end
 
-def get_about_info(ucid)
+def get_about_info(ucid, locale)
   client = make_client(YT_URL)
 
   about = client.get("/channel/#{ucid}/about?disable_polymer=1&gl=US&hl=en")
@@ -234,14 +234,14 @@ def get_about_info(ucid)
   about = XML.parse_html(about.body)
 
   if about.xpath_node(%q(//div[contains(@class, "channel-empty-message")]))
-    error_message = "This channel does not exist."
+    error_message = translate(locale, "This channel does not exist.")
 
     raise error_message
   end
 
   if about.xpath_node(%q(//span[contains(@class,"qualified-channel-title-text")]/a)).try &.content.empty?
     error_message = about.xpath_node(%q(//div[@class="yt-alert-content"])).try &.content.strip
-    error_message ||= "Could not get channel info."
+    error_message ||= translate(locale, "Could not get channel info.")
 
     raise error_message
   end

src/invidious/comments.cr

@@ -56,7 +56,7 @@ class RedditListing
   })
 end
 
-def fetch_youtube_comments(id, continuation, proxies, format)
+def fetch_youtube_comments(id, continuation, proxies, format, locale)
   client = make_client(YT_URL)
   html = client.get("/watch?v=#{id}&gl=US&hl=en&disable_polymer=1&has_verified=1&bpctr=9999999999")
   headers = HTTP::Headers.new
@@ -133,7 +133,7 @@ def fetch_youtube_comments(id, continuation, proxies, format)
   response = JSON.parse(response.body)
 
   if !response["response"]["continuationContents"]?
-    raise "Could not fetch comments"
+    raise translate(locale, "Could not fetch comments")
   end
 
   response = response["response"]["continuationContents"]
@@ -214,7 +214,7 @@ def fetch_youtube_comments(id, continuation, proxies, format)
               json.field "content", content
               json.field "contentHtml", content_html
               json.field "published", published.to_unix
-              json.field "publishedText", "#{recode_date(published)} ago"
+              json.field "publishedText", translate(locale, "`x` ago", recode_date(published))
               json.field "likeCount", node_comment["likeCount"]
               json.field "commentId", node_comment["commentId"]
 
@@ -250,7 +250,7 @@ def fetch_youtube_comments(id, continuation, proxies, format)
 
   if format == "html"
     comments = JSON.parse(comments)
-    content_html = template_youtube_comments(comments)
+    content_html = template_youtube_comments(comments, locale)
 
     comments = JSON.build do |json|
       json.object do
@@ -296,7 +296,7 @@ def fetch_reddit_comments(id)
   return comments, thread
 end
 
-def template_youtube_comments(comments)
+def template_youtube_comments(comments, locale)
   html = ""
 
   root = comments["comments"].as_a
@@ -308,7 +308,7 @@ def template_youtube_comments(comments)
         <div class="pure-u-23-24">
           <p>
             <a href="javascript:void(0)" data-continuation="#{child["replies"]["continuation"]}"
-              onclick="get_youtube_replies(this)">View #{child["replies"]["replyCount"]} replies</a>
+              onclick="get_youtube_replies(this)">#{translate(locale, "View `x` replies", child["replies"]["replyCount"].to_s)}</a>
           </p>
         </div>
       </div>
@@ -328,7 +328,7 @@ def template_youtube_comments(comments)
             <a href="#{child["authorUrl"]}">#{child["author"]}</a>
           </b> 
           <p style="white-space:pre-wrap">#{child["contentHtml"]}</p>
-          #{recode_date(Time.unix(child["published"].as_i64))} ago
+          #{translate(locale, "`x` ago", recode_date(Time.unix(child["published"].as_i64)))}
           | 
           <i class="icon ion-ios-thumbs-up"></i> #{number_with_separator(child["likeCount"])} 
         </p>
@@ -344,7 +344,7 @@ def template_youtube_comments(comments)
       <div class="pure-u-1">
         <p>
           <a href="javascript:void(0)" data-continuation="#{comments["continuation"]}"
-            onclick="get_youtube_replies(this, true)">Load more</a>
+            onclick="get_youtube_replies(this, true)">#{translate(locale, "Load more")}</a>
         </p>
       </div>
     </div>
@@ -354,7 +354,7 @@ def template_youtube_comments(comments)
   return html
 end
 
-def template_reddit_comments(root)
+def template_reddit_comments(root, locale)
   html = ""
   root.each do |child|
     if child.data.is_a?(RedditComment)
@@ -366,15 +366,15 @@ def template_reddit_comments(root)
       replies_html = ""
       if child.replies.is_a?(RedditThing)
         replies = child.replies.as(RedditThing)
-        replies_html = template_reddit_comments(replies.data.as(RedditListing).children)
+        replies_html = template_reddit_comments(replies.data.as(RedditListing).children, locale)
       end
 
       content = <<-END_HTML
       <p>
         <a href="javascript:void(0)" onclick="toggle_parent(this)">[ - ]</a> 
         <b><a href="https://www.reddit.com/user/#{author}">#{author}</a></b> 
-        #{number_with_separator(score)} points 
-        #{recode_date(child.created_utc)} ago
+        #{translate(locale, "`x` points", number_with_separator(score))}
+        #{translate(locale, "`x` ago", recode_date(child.created_utc))}
       </p>
       <div>
       #{body_html}

src/invidious/helpers/i18n.cr

@@ -0,0 +1,23 @@
+def load_locale(name)
+  return JSON.parse(File.read("locales/#{name}.json")).as_h
+end
+
+def translate(locale : Hash(String, JSON::Any) | Nil, translation : String, text : String | Nil = nil)
+  if !locale
+    return translation
+  end
+
+  # if !locale[translation]?
+  #   puts "Could not find translation for #{translation}"
+  # end
+
+  if locale[translation]? && !locale[translation].as_s.empty?
+    translation = locale[translation].as_s
+  end
+
+  if text
+    translation = translation.gsub("`x`", text)
+  end
+
+  return translation
+end

src/invidious/mixes.cr

@@ -18,7 +18,7 @@ class Mix
   })
 end
 
-def fetch_mix(rdid, video_id, cookies = nil)
+def fetch_mix(rdid, video_id, cookies = nil, locale = nil)
   client = make_client(YT_URL)
   headers = HTTP::Headers.new
   headers["User-Agent"] = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36"
@@ -32,11 +32,11 @@ def fetch_mix(rdid, video_id, cookies = nil)
   if yt_data
     yt_data = JSON.parse(yt_data["data"].rchop(";"))
   else
-    raise "Could not create mix."
+    raise translate(locale, "Could not create mix.")
   end
 
   if !yt_data["contents"]["twoColumnWatchNextResults"]["playlist"]?
-    raise "Could not create mix."
+    raise translate(locale, "Could not create mix.")
   end
 
   playlist = yt_data["contents"]["twoColumnWatchNextResults"]["playlist"]["playlist"]
@@ -70,7 +70,7 @@ def fetch_mix(rdid, video_id, cookies = nil)
   end
 
   if !cookies
-    next_page = fetch_mix(rdid, videos[-1].id, response.cookies)
+    next_page = fetch_mix(rdid, videos[-1].id, response.cookies, locale)
     videos += next_page.videos
   end
 

src/invidious/playlists.cr

@@ -26,7 +26,7 @@ class Playlist
   })
 end
 
-def fetch_playlist_videos(plid, page, video_count, continuation = nil)
+def fetch_playlist_videos(plid, page, video_count, continuation = nil, locale = nil)
   client = make_client(YT_URL)
 
   if continuation
@@ -48,7 +48,7 @@ def fetch_playlist_videos(plid, page, video_count, continuation = nil)
     response = client.get(url)
     response = JSON.parse(response.body)
     if !response["content_html"]? || response["content_html"].as_s.empty?
-      raise "Playlist is empty"
+      raise translate(locale, "Playlist is empty")
     end
 
     document = XML.parse_html(response["content_html"].as_s)
@@ -105,14 +105,14 @@ def extract_playlist(plid, nodeset, index)
     end
 
     videos << PlaylistVideo.new(
-      title,
-      id,
-      author,
-      ucid,
-      length_seconds,
-      Time.now,
-      [plid],
-      index + offset,
+      title: title,
+      id: id,
+      author: author,
+      ucid: ucid,
+      length_seconds: length_seconds,
+      published: Time.now,
+      playlists: [plid],
+      index: index + offset,
     )
   end
 
@@ -155,7 +155,7 @@ def produce_playlist_url(id, index)
   return url
 end
 
-def fetch_playlist(plid)
+def fetch_playlist(plid, locale)
   client = make_client(YT_URL)
 
   if plid.starts_with? "UC"
@@ -164,7 +164,7 @@ def fetch_playlist(plid)
 
   response = client.get("/playlist?list=#{plid}&hl=en&disable_polymer=1")
   if response.status_code != 200
-    raise "Invalid playlist."
+    raise translate(locale, "Invalid playlist.")
   end
 
   body = response.body.gsub(%(
@@ -175,7 +175,7 @@ def fetch_playlist(plid)
 
   title = document.xpath_node(%q(//h1[@class="pl-header-title"]))
   if !title
-    raise "Playlist does not exist."
+    raise translate(locale, "Playlist does not exist.")
   end
   title = title.content.strip(" \n")
 

src/invidious/trending.cr

@@ -1,4 +1,4 @@
-def fetch_trending(trending_type, proxies, region)
+def fetch_trending(trending_type, proxies, region, locale)
   client = make_client(YT_URL)
   headers = HTTP::Headers.new
   headers["User-Agent"] = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36"
@@ -16,7 +16,7 @@ def fetch_trending(trending_type, proxies, region)
     if yt_data
       yt_data = JSON.parse(yt_data["data"].rchop(";"))
     else
-      raise "Could not pull trending pages."
+      raise translate(locale, "Could not pull trending pages.")
     end
 
     tabs = yt_data["contents"]["twoColumnBrowseResultsRenderer"]["tabs"][0]["tabRenderer"]["content"]["sectionListRenderer"]["subMenu"]["channelListSubMenuRenderer"]["contents"].as_a

src/invidious/users.cr

@@ -29,20 +29,25 @@ class User
 end
 
 DEFAULT_USER_PREFERENCES = Preferences.from_json({
-  "video_loop"     => false,
-  "autoplay"       => false,
-  "speed"          => 1.0,
-  "quality"        => "hd720",
-  "volume"         => 100,
-  "comments"       => ["youtube", ""],
-  "captions"       => ["", "", ""],
-  "related_videos" => true,
-  "dark_mode"      => false,
-  "thin_mode"      => false,
-  "max_results"    => 40,
-  "sort"           => "published",
-  "latest_only"    => false,
-  "unseen_only"    => false,
+  "video_loop"         => false,
+  "autoplay"           => false,
+  "continue"           => false,
+  "listen"             => false,
+  "speed"              => 1.0,
+  "quality"            => "hd720",
+  "volume"             => 100,
+  "comments"           => ["youtube", ""],
+  "captions"           => ["", "", ""],
+  "related_videos"     => true,
+  "redirect_feed"      => false,
+  "locale"             => "en-US",
+  "dark_mode"          => false,
+  "thin_mode"          => false,
+  "max_results"        => 40,
+  "sort"               => "published",
+  "latest_only"        => false,
+  "unseen_only"        => false,
+  "notifications_only" => false,
 }.to_json)
 
 class Preferences
@@ -113,6 +118,10 @@ class Preferences
       type:    Bool,
       default: false,
     },
+    locale: {
+      type:    String,
+      default: "en-US",
+    },
   })
 end
 
@@ -217,13 +226,13 @@ def create_response(user_id, operation, key, db, expire = 6.hours)
   return challenge, token
 end
 
-def validate_response(challenge, token, user_id, operation, key, db)
+def validate_response(challenge, token, user_id, operation, key, db, locale)
   if !challenge
-    raise "Hidden field \"challenge\" is a required field"
+    raise translate(locale, "Hidden field \"challenge\" is a required field")
   end
 
   if !token
-    raise "Hidden field \"token\" is a required field"
+    raise translate(locale, "Hidden field \"token\" is a required field")
   end
 
   challenge = Base64.decode_string(challenge)
@@ -233,7 +242,7 @@ def validate_response(challenge, token, user_id, operation, key, db)
     expire = expire.to_i?
     expire ||= 0
   else
-    raise "Invalid challenge"
+    raise translate(locale, "Invalid challenge")
   end
 
   challenge = OpenSSL::HMAC.digest(:sha256, HMAC_KEY, challenge)
@@ -242,23 +251,23 @@ def validate_response(challenge, token, user_id, operation, key, db)
   if db.query_one?("SELECT EXISTS (SELECT true FROM nonces WHERE nonce = $1)", nonce, as: Bool)
     db.exec("DELETE FROM nonces * WHERE nonce = $1", nonce)
   else
-    raise "Invalid token"
+    raise translate(locale, "Invalid token")
   end
 
   if challenge != token
-    raise "Invalid token"
+    raise translate(locale, "Invalid token")
   end
 
   if challenge_operation != operation
-    raise "Invalid token"
+    raise translate(locale, "Invalid token")
   end
 
   if challenge_user_id != user_id
-    raise "Invalid user"
+    raise translate(locale, "Invalid user")
   end
 
   if expire < Time.now.to_unix
-    raise "Token is expired, please try again"
+    raise translate(locale, "Token is expired, please try again")
   end
 end
 

src/invidious/views/channel.ecr

@@ -19,14 +19,14 @@
     <p>
         <a id="subscribe" onclick="unsubscribe()" class="pure-button pure-button-primary" 
             href="/subscription_ajax?action_remove_subscriptions=1&c=<%= ucid %>&referer=<%= env.get("current_page") %>">
-            <b>Unsubscribe | <%= number_to_short_text(sub_count) %></b>
+            <b><%= translate(locale, "Unsubscribe") %> | <%= number_to_short_text(sub_count) %></b>
         </a>
     </p>
     <% else %>
     <p>
         <a id="subscribe" onclick="subscribe()" class="pure-button pure-button-primary" 
             href="/subscription_ajax?action_create_subscription_to_channel=1&c=<%= ucid %>&referer=<%= env.get("current_page") %>">
-            <b>Subscribe | <%= number_to_short_text(sub_count) %></b>
+            <b><%= translate(locale, "Subscribe") %> | <%= number_to_short_text(sub_count) %></b>
         </a>
     </p>
     <% end %>
@@ -34,7 +34,7 @@
     <p>
         <a id="subscribe" class="pure-button pure-button-primary" 
             href="/login?referer=<%= env.get("current_page") %>">
-            <b>Login to subscribe to <%= author %></b>
+            <b><%= translate(locale, "Login to subscribe to `x`", author) %></b>
         </a>
     </p>
 <% end %>
@@ -42,7 +42,7 @@
 
 <div class="pure-g h-box">
     <div class="pure-u-1-3">
-        <a href="https://www.youtube.com/channel/<%= ucid %>">View channel on YouTube</a>
+        <a href="https://www.youtube.com/channel/<%= ucid %>"><%= translate(locale, "View channel on YouTube") %></a>
     </div>
     <div class="pure-u-1-3">
     </div>
@@ -51,10 +51,10 @@
         <% {"newest", "oldest", "popular"}.each do |sort| %>
             <div class="pure-u-1 pure-md-1-3">
                 <% if sort_by == sort %>
-                <b><%= sort %></b>
+                <b><%= translate(locale, sort) %></b>
                 <% else %>
                 <a href="/channel/<%= ucid %>?page=<%= page %>&sort_by=<%= sort %>">
-                <%= sort %>
+                <%= translate(locale, sort) %>
                 </a>
                 <% end %>
             </div>
@@ -78,13 +78,17 @@
 <div class="pure-g h-box">
     <div class="pure-u-1 pure-u-md-1-5">
     <% if page >= 2 %>
-        <a href="/channel/<%= ucid %>?page=<%= page - 1 %><% if sort_by != "newest" %>&sort_by=<%= sort_by %><% end %>">Previous page</a>
+        <a href="/channel/<%= ucid %>?page=<%= page - 1 %><% if sort_by != "newest" %>&sort_by=<%= sort_by %><% end %>">
+            <%= translate(locale, "Previous page") %>
+        </a>
     <% end %>
     </div>
     <div class="pure-u-1 pure-u-md-3-5"></div>
     <div style="text-align:right;" class="pure-u-1 pure-u-md-1-5">
     <% if count == 60 %>
-        <a href="/channel/<%= ucid %>?page=<%= page + 1 %><% if sort_by != "newest" %>&sort_by=<%= sort_by %><% end %>">Next page</a>
+        <a href="/channel/<%= ucid %>?page=<%= page + 1 %><% if sort_by != "newest" %>&sort_by=<%= sort_by %><% end %>">
+            <%= translate(locale, "Next page") %>
+        </a>
     <% end %>
     </div>
 </div>
@@ -105,7 +109,7 @@ function subscribe() {
             if (xhr.status == 200) {
                 subscribe_button = document.getElementById("subscribe");
                 subscribe_button.onclick = unsubscribe;
-                subscribe_button.innerHTML = '<b>Unsubscribe | <%= number_to_short_text(sub_count) %></b>'
+                subscribe_button.innerHTML = '<b><%= translate(locale, "Unsubscribe") %> | <%= number_to_short_text(sub_count) %></b>'
             }
         }
     }
@@ -124,7 +128,7 @@ function unsubscribe() {
             if (xhr.status == 200) {
                 subscribe_button = document.getElementById("subscribe");
                 subscribe_button.onclick = subscribe;
-                subscribe_button.innerHTML = '<b>Subscribe | <%= number_to_short_text(sub_count) %></b>'
+                subscribe_button.innerHTML = '<b><%= translate(locale, "Subscribe") %> | <%= number_to_short_text(sub_count) %></b>'
             }
         }
     }

src/invidious/views/clear_watch_history.ecr

@@ -1,13 +1,21 @@
+<% content_for "header" do %>
+<title><%= translate(locale, "Clear watch history") %> - Invidious</title>
+<% end %>
+
 <div class="h-box">
     <form class="pure-form pure-form-aligned" action="/clear_watch_history?referer=<%= URI.escape(referer) %>" method="post">
-        <legend>Clear watch history?</legend>
+        <legend><%= translate(locale, "Clear watch history?") %></legend>
 
         <div class="pure-g">
             <div class="pure-u-1-2">
-                <button type="submit" name="submit" value="clear_watch_history" class="pure-button pure-button-primary">Yes</button>
+                <button type="submit" name="submit" value="clear_watch_history" class="pure-button pure-button-primary">
+                    <%= translate(locale, "Yes") %>
+                </button>
             </div>
             <div class="pure-u-1-2">
-                <a class="pure-button" href="<%= referer %>">No</a>
+                <a class="pure-button" href="<%= referer %>">
+                    <%= translate(locale, "No") %>
+                </a>
             </div>
         </div>
 

src/invidious/views/components/item.ecr

@@ -11,8 +11,8 @@
             <% end %>
             <p><%= item.author %></p>
         </a>
-        <p><%= number_with_separator(item.subscriber_count) %> subscribers</p>
-        <p><%= number_with_separator(item.video_count) %> videos</p>
+        <p><%= translate(locale, "`x` subscribers", number_with_separator(item.subscriber_count)) %></p>
+        <p><%= translate(locale, "`x` videos", number_with_separator(item.video_count)) %></p>
         <h5><%= item.description_html %></h5>
     <% when SearchPlaylist %>
         <% if item.id.starts_with? "RD" %>
@@ -59,14 +59,14 @@
             <p><%= item.title %></p>
         </a>
         <% if item.responds_to?(:live_now) && item.live_now %>
-        <p>LIVE</p>
+        <p><%= translate(locale, "LIVE") %></p>
         <% end %>
         <p>
             <b><a style="width:100%;" href="/channel/<%= item.ucid %>"><%= item.author %></a></b>
         </p>
         
         <% if Time.now - item.published > 1.minute %>
-        <h5>Shared <%= recode_date(item.published) %> ago</h5>
+        <h5><%= translate(locale, "Shared `x` ago", recode_date(item.published)) %></h5>
         <% end %>
     <% else %>
         <% if env.get?("user") && env.get("user").as(User).preferences.thin_mode %>
@@ -93,14 +93,14 @@
         <% end %>
         <p><a href="/watch?v=<%= item.id %>"><%= item.title %></a></p>
         <% if item.responds_to?(:live_now) && item.live_now %>
-        <p>LIVE</p>
+        <p><%= translate(locale, "LIVE") %></p>
         <% end %>
         <p>
             <b><a style="width:100%;" href="/channel/<%= item.ucid %>"><%= item.author %></a></b>
         </p>
         
         <% if Time.now - item.published > 1.minute %>
-        <h5>Shared <%= recode_date(item.published) %> ago</h5>
+        <h5><%= translate(locale, "Shared `x` ago", recode_date(item.published)) %></h5>
         <% end %>
     <% end %>
     </div>

src/invidious/views/components/player.ecr

@@ -27,12 +27,12 @@
         <% end %>
 
         <% preferred_captions.each_with_index do |caption, i| %>
-        <track kind="captions" src="/api/v1/captions/<%= video.id %>?label=<%= caption.name.simpleText %>"
+        <track kind="captions" src="/api/v1/captions/<%= video.id %>?label=<%= caption.name.simpleText %>&hl=<%= env.get("locale").as(String) %>"
             label="<%= caption.name.simpleText %>" <% if i == 0 %>default<% end %>>
         <% end %>
 
         <% captions.each do |caption| %>
-        <track kind="captions" src="/api/v1/captions/<%= video.id %>?label=<%= caption.name.simpleText %>"
+        <track kind="captions" src="/api/v1/captions/<%= video.id %>?label=<%= caption.name.simpleText %>&hl=<%= env.get("locale").as(String) %>"
             label="<%= caption.name.simpleText %>">
         <% end %>
     <% end %>

src/invidious/views/data_control.ecr

@@ -1,54 +1,57 @@
 <% content_for "header" do %>
-<title>Import and Export Data - Invidious</title>
+<title><%= translate(locale, "Import and Export Data") %> - Invidious</title>
 <% end %>
 
 <div class="h-box">
     <form class="pure-form pure-form-aligned" enctype="multipart/form-data" action="/data_control?referer=<%= referer %>" method="post">
         <fieldset>
-            <legend>Import</legend>
+            <legend><%= translate(locale, "Import") %></legend>
 
             <div class="pure-control-group">
-                <label for="import_youtube">Import Invidious data</label>
+                <label for="import_youtube"><%= translate(locale, "Import Invidious data") %></label>
                 <input type="file" id="import_invidious" name="import_invidious">
             </div>
 
             <div class="pure-control-group">
-                <label for="import_youtube">Import <a rel="noopener" target="_blank"
-                        href="https://support.google.com/youtube/answer/6224202?hl=en-GB">YouTube subscriptions</a></label>
+                <label for="import_youtube">
+                    <a rel="noopener" target="_blank" href="https://support.google.com/youtube/answer/6224202?hl=en">
+                        <%= translate(locale, "Import YouTube subscriptions") %>
+                    </a>
+                </label>
                 <input type="file" id="import_youtube" name="import_youtube">
             </div>
             
             <div class="pure-control-group">
-                <label for="import_freetube">Import Freetube subscriptions (.db)</label>
+                <label for="import_freetube"><%= translate(locale, "Import Freetube subscriptions (.db)") %></label>
                 <input type="file" id="import_freetube" name="import_freetube">
             </div>
 
             <div class="pure-control-group">
-                <label for="import_newpipe_subscriptions">Import NewPipe subscriptions (.json)</label>
+                <label for="import_newpipe_subscriptions"><%= translate(locale, "Import NewPipe subscriptions (.json)") %></label>
                 <input type="file" id="import_newpipe_subscriptions" name="import_newpipe_subscriptions">
             </div>
 
             <div class="pure-control-group">
-                <label for="import_newpipe">Import NewPipe data (.zip)</label>
+                <label for="import_newpipe"><%= translate(locale, "Import NewPipe data (.zip)") %></label>
                 <input type="file" id="import_newpipe" name="import_newpipe">
             </div>
         
             <div class="pure-controls">
-                <button type="submit" class="pure-button pure-button-primary">Import</button>
+                <button type="submit" class="pure-button pure-button-primary"><%= translate(locale, "Import") %></button>
             </div>
 
-            <legend>Export</legend>
+            <legend><%= translate(locale, "Export") %></legend>
 
             <div class="pure-control-group">
-                <a href="/subscription_manager?action_takeout=1">Export subscriptions as OPML</a>
+                <a href="/subscription_manager?action_takeout=1"><%= translate(locale, "Export subscriptions as OPML") %></a>
             </div>
 
             <div class="pure-control-group">
-                <a href="/subscription_manager?action_takeout=1&format=newpipe">Export subscriptions as OPML (for NewPipe & FreeTube)</a>
+                <a href="/subscription_manager?action_takeout=1&format=newpipe"><%= translate(locale, "Export subscriptions as OPML (for NewPipe & FreeTube)") %></a>
             </div>
 
             <div class="pure-control-group">
-                <a href="/subscription_manager?action_takeout=1&format=json">Export data as JSON</a>
+                <a href="/subscription_manager?action_takeout=1&format=json"><%= translate(locale, "Export data as JSON") %></a>
             </div>
         </fieldset>
     </form>

src/invidious/views/delete_account.ecr

@@ -1,13 +1,21 @@
+<% content_for "header" do %>
+<title><%= translate(locale, "Delete account") %> - Invidious</title>
+<% end %>
+
 <div class="h-box">
     <form class="pure-form pure-form-aligned" action="/delete_account?referer=<%= URI.escape(referer) %>" method="post">
-        <legend>Delete account?</legend>
+        <legend><%= translate(locale, "Delete account?") %></legend>
 
         <div class="pure-g">
             <div class="pure-u-1-2">
-                <button type="submit" name="submit" value="delete_account" class="pure-button pure-button-primary">Yes</button>
+                <button type="submit" name="submit" value="delete_account" class="pure-button pure-button-primary">
+                    <%= translate(locale, "Yes") %>
+                </button>
             </div>
             <div class="pure-u-1-2">
-                <a class="pure-button" href="<%= referer %>">No</a>
+                <a class="pure-button" href="<%= referer %>">
+                    <%= translate(locale, "No") %>
+                </a>
             </div>
         </div>
 

src/invidious/views/history.ecr

@@ -1,14 +1,14 @@
 <% content_for "header" do %>
-<title>History - Invidious</title>
+<title><%= translate(locale, "History") %> - Invidious</title>
 <% end %>
 
 <div class="pure-g h-box">
     <div class="pure-u-2-3">
-        <h3><span id="count"><%= user.watched.size %></span> videos</h3>
+        <h3><%= translate(locale, "`x` videos", %(<span id="count">#{user.watched.size}</span>)) %></h3>
     </div>
     <div class="pure-u-1-3" style="text-align:right;">
         <h3>
-            <a href="/clear_watch_history">Clear watch history</a>
+            <a href="/clear_watch_history"><%= translate(locale, "Clear watch history") %></a>
         </h3>
     </div>
 </div>
@@ -69,13 +69,17 @@ function mark_unwatched(target) {
 <div class="pure-g h-box">
     <div class="pure-u-1 pure-u-md-1-5">
     <% if page >= 2 %>
-        <a href="/feed/history?page=<%= page - 1 %>">Previous page</a>
+        <a href="/feed/history?page=<%= page - 1 %>">
+            <%= translate(locale, "Previous page") %>
+        </a>
     <% end %>
     </div>
     <div class="pure-u-1 pure-u-md-3-5"></div>
     <div style="text-align:right;" class="pure-u-1 pure-u-md-1-5">
     <% if watched.size >= limit %>
-        <a href="/feed/history?page=<%= page + 1 %>">Next page</a>
+        <a href="/feed/history?page=<%= page + 1 %>">
+            <%= translate(locale, "Next page") %>
+        </a>
     <% end %>
     </div>
 </div>

src/invidious/views/index.ecr

@@ -1,5 +1,5 @@
 <% content_for "header" do %>
-<meta name="description" content="An alternative front-end to YouTube">
+<meta name="description" content="<%= translate(locale, "An alternative front-end to YouTube") %>">
 <title>Invidious</title>
 <% end %>
 

src/invidious/views/licenses.ecr

@@ -7,7 +7,7 @@
 </head>
 
 <body>
-    <h1>JavaScript license information</h1>
+    <h1><%= translate(locale, "JavaScript license information") %></h1>
     <table id="jslicense-labels1">
         <tr>
             <td>
@@ -19,7 +19,7 @@
             </td>
 
             <td>
-                <a href="https://unpkg.com/dashjs@2.9.0/dist/dash.mediaplayer.debug.js">source</a>
+                <a href="https://unpkg.com/dashjs@2.9.0/dist/dash.mediaplayer.debug.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
 
@@ -33,7 +33,7 @@
             </td>
 
             <td>
-                <a href="/js/silvermine-videojs-quality-selector.js">source</a>
+                <a href="/js/silvermine-videojs-quality-selector.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
 
@@ -47,7 +47,7 @@
             </td>
 
             <td>
-                <a href="https://unpkg.com/video.js@6.12.1/dist/video.js">source</a>
+                <a href="https://unpkg.com/video.js@6.12.1/dist/video.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
 
@@ -61,7 +61,7 @@
             </td>
 
             <td>
-                <a href="https://unpkg.com/videojs-contrib-quality-levels@2.0.7/dist/videojs-contrib-quality-levels.js">source</a>
+                <a href="https://unpkg.com/videojs-contrib-quality-levels@2.0.7/dist/videojs-contrib-quality-levels.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
 
@@ -75,7 +75,7 @@
             </td>
 
             <td>
-                <a href="https://unpkg.com/videojs-contrib-dash@2.8.2/dist/videojs-dash.js">source</a>
+                <a href="https://unpkg.com/videojs-contrib-dash@2.8.2/dist/videojs-dash.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
 
@@ -89,7 +89,7 @@
             </td>
 
             <td>
-                <a href="https://unpkg.com/@videojs/http-streaming@1.2.2/dist/videojs-http-streaming.js">source</a>
+                <a href="https://unpkg.com/@videojs/http-streaming@1.2.2/dist/videojs-http-streaming.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
 
@@ -103,7 +103,7 @@
             </td>
 
             <td>
-                <a href="https://unpkg.com/videojs-markers@1.0.1/dist/videojs-markers.js">source</a>
+                <a href="https://unpkg.com/videojs-markers@1.0.1/dist/videojs-markers.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
 
@@ -117,7 +117,7 @@
             </td>
 
             <td>
-                <a href="https://unpkg.com/videojs-share@2.0.1/dist/videojs-share.js">source</a>
+                <a href="https://unpkg.com/videojs-share@2.0.1/dist/videojs-share.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
 
@@ -131,7 +131,7 @@
             </td>
 
             <td>
-                <a href="/js/videojs.hotkeys.js">source</a>
+                <a href="/js/videojs.hotkeys.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
 
@@ -145,7 +145,7 @@
             </td>
 
             <td>
-                <a href="/js/watch.js">source</a>
+                <a href="/js/watch.js"><%= translate(locale, "source") %></a>
             </td>
         </tr>
     </table>

src/invidious/views/login.ecr

@@ -1,5 +1,5 @@
 <% content_for "header" do %>
-<title>Login - Invidious</title>
+<title><%= translate(locale, "Login") %> - Invidious</title>
 <% end %>
 
 <div class="pure-g">
@@ -8,31 +8,37 @@
         <div class="h-box">
             <div class="pure-g">
                 <div class="pure-u-1-2">
-                    <a class="pure-button <% if account_type == "invidious" %>pure-button-disabled<% end %>" href="/login">Login/Register</a>
+                    <a class="pure-button <% if account_type == "invidious" %>pure-button-disabled<% end %>" href="/login">
+                        <%= translate(locale, "Login/Register") %>
+                    </a>
                 </div>
                 <div class="pure-u-1-2">
-                    <a class="pure-button <% if account_type == "google" %>pure-button-disabled<% end %>" href="/login?type=google">Login to Google</a>
+                    <a class="pure-button <% if account_type == "google" %>pure-button-disabled<% end %>" href="/login?type=google">
+                        <%= translate(locale, "Login to Google") %>
+                    </a>
                 </div>
             </div>
             <hr>
             <% if account_type == "invidious" %>
             <form class="pure-form pure-form-stacked" action="/login?referer=<%= URI.escape(referer) %>&type=invidious" method="post">
                 <fieldset>
-                    <label for="email">User ID:</label>
+                    <label for="email"><%= translate(locale, "User ID:") %></label>
                     <input required class="pure-input-1" name="email" type="text" placeholder="User ID">
 
-                    <label for="password">Password:</label>
+                    <label for="password"><%= translate(locale, "Password:") %></label>
                     <input required class="pure-input-1" name="password" type="password" placeholder="Password">
                 
                 <% if captcha_type == "image" %>
                     <img style="width:100%" src='<%= captcha.not_nil![:image] %>'/>
                     <input type="hidden" name="token" value="<%= captcha.not_nil![:token] %>">
                     <input type="hidden" name="challenge" value="<%= captcha.not_nil![:challenge] %>">
-                    <label for="answer">Time (h:mm:ss):</label>
+                    <label for="answer"><%= translate(locale, "Time (h:mm:ss):") %></label>
                     <input required type="text" name="answer" type="text" placeholder="h:mm:ss">
                     
                     <label>
-                        <a href="/login?referer=<%= URI.escape(referer) %>&type=invidious&captcha=text">Text CAPTCHA</a>
+                        <a href="/login?referer=<%= URI.escape(referer) %>&type=invidious&captcha=text">
+                            <%= translate(locale, "Text CAPTCHA") %>
+                        </a>
                     </label>
                 <% else %>
                     <% text_captcha.not_nil![:tokens].each_with_index do |token, i| %>
@@ -43,29 +49,31 @@
                     <input required type="text" name="text_answer" type="text" placeholder="Answer">
 
                     <label>
-                        <a href="/login?referer=<%= URI.escape(referer) %>&type=invidious">Image CAPTCHA</a>
+                        <a href="/login?referer=<%= URI.escape(referer) %>&type=invidious">
+                            <%= translate(locale, "Image CAPTCHA") %>
+                        </a>
                     </label>
                 <% end %>
 
-                    <button type="submit" name="action" value="signin" class="pure-button pure-button-primary">Sign In</button>
-                    <button type="submit" name="action" value="register" class="pure-button pure-button-primary">Register</button>
+                    <button type="submit" name="action" value="signin" class="pure-button pure-button-primary"><%= translate(locale, "Sign In") %></button>
+                    <button type="submit" name="action" value="register" class="pure-button pure-button-primary"><%= translate(locale, "Register") %></button>
                 </fieldset>
             </form>
             <% elsif account_type == "google" %>
             <form class="pure-form pure-form-stacked" action="/login?referer=<%= URI.escape(referer) %>" method="post">
                 <fieldset>
-                    <label for="email">Email:</label>
+                    <label for="email"><%= translate(locale, "Email:") %></label>
                     <input required class="pure-input-1" name="email" type="email" placeholder="Email">
 
-                    <label for="password">Password:</label>
+                    <label for="password"><%= translate(locale, "Password:") %></label>
                     <input required class="pure-input-1" name="password" type="password" placeholder="Password">
                     
                     <% if tfa %>
-                    <label for="tfa">Google verification code:</label>
+                    <label for="tfa"><%= translate(locale, "Google verification code:") %></label>
                     <input required class="pure-input-1" name="tfa" type="text" placeholder="Google verification code">
                     <% end %>
 
-                    <button type="submit" class="pure-button pure-button-primary">Sign In</button>
+                    <button type="submit" class="pure-button pure-button-primary"><%= translate(locale, "Sign In") %></button>
                 </fieldset>
             </form>
             <% end %>

src/invidious/views/playlist.ecr

@@ -35,13 +35,17 @@
 <div class="pure-g h-box">
     <div class="pure-u-1 pure-u-md-1-5">
     <% if page >= 2 %>
-        <a href="/playlist?list=<%= playlist.id %>&page=<%= page - 1 %>">Previous page</a>
+        <a href="/playlist?list=<%= playlist.id %>&page=<%= page - 1 %>">
+            <%= translate(locale, "Previous page") %>
+        </a>
     <% end %>
     </div>
     <div class="pure-u-1 pure-u-md-3-5"></div>
     <div style="text-align:right;" class="pure-u-1 pure-u-md-1-5">
     <% if videos.size == 100 %>
-        <a href="/playlist?list=<%= playlist.id %>&page=<%= page + 1 %>">Next page</a>
+        <a href="/playlist?list=<%= playlist.id %>&page=<%= page + 1 %>">
+            <%= translate(locale, "Next page") %>
+        </a>
     <% end %>
     </div>
 </div>

src/invidious/views/popular.ecr

@@ -1,3 +1,7 @@
+<% content_for "header" do %>
+<title><%= translate(locale, "Popular") %> - Invidious</title>
+<% end %>
+
 <div class="pure-g">
 <% popular_videos.each_slice(4) do |slice| %>
         <% slice.each do |item| %>

src/invidious/views/preferences.ecr

@@ -1,5 +1,5 @@
 <% content_for "header" do %>
-<title>Preferences - Invidious</title>
+<title><%= translate(locale, "Preferences") %> - Invidious</title>
 <% end %>
 
 <script>
@@ -11,30 +11,30 @@ function update_value(element) {
 <div class="h-box">
     <form class="pure-form pure-form-aligned" action="/preferences?referer=<%= referer %>" method="post">
         <fieldset>
-            <legend>Player preferences</legend>
+            <legend><%= translate(locale, "Player preferences") %></legend>
 
             <div class="pure-control-group">
-                <label for="video_loop">Always loop: </label>
+                <label for="video_loop"><%= translate(locale, "Always loop: ") %></label>
                 <input name="video_loop" id="video_loop" type="checkbox" <% if user.preferences.video_loop %>checked<% end %>>
             </div>
 
             <div class="pure-control-group">
-                <label for="autoplay">Autoplay: </label>
+                <label for="autoplay"><%= translate(locale, "Autoplay: ") %></label>
                 <input name="autoplay" id="autoplay" type="checkbox" <% if user.preferences.autoplay %>checked<% end %>>
             </div>
 
             <div class="pure-control-group">
-                <label for="continue">Autoplay next video: </label>
+                <label for="continue"><%= translate(locale, "Autoplay next video: ") %></label>
                 <input name="continue" id="continue" type="checkbox" <% if user.preferences.continue %>checked<% end %>>
             </div>
 
             <div class="pure-control-group">
-                <label for="listen">Listen by default: </label>
+                <label for="listen"><%= translate(locale, "Listen by default: ") %></label>
                 <input name="listen" id="listen" type="checkbox" <% if user.preferences.listen %>checked<% end %>>
             </div>
 
             <div class="pure-control-group">
-                <label for="speed">Default speed: </label>
+                <label for="speed"><%= translate(locale, "Default speed: ") %></label>
                 <select name="speed" id="speed">
                 <% {2.0, 1.5, 1.0, 0.5}.each do |option| %>
                     <option <% if user.preferences.speed == option %> selected <% end %>><%= option %></option>
@@ -43,96 +43,105 @@ function update_value(element) {
             </div>
 
             <div class="pure-control-group">
-                <label for="quality">Preferred video quality: </label>
+                <label for="quality"><%= translate(locale, "Preferred video quality: ") %></label>
                 <select name="quality" id="quality">
                 <% {"dash", "hd720", "medium", "small"}.each do |option| %>
-                    <option <% if user.preferences.quality == option %> selected <% end %>><%= option %></option>
+                    <option value="<%= option %>" <% if user.preferences.quality == option %> selected <% end %>><%= translate(locale, option) %></option>
                 <% end %>
                 </select>
             </div>
 
             <div class="pure-control-group">
-                <label for="volume">Player volume: </label>
+                <label for="volume"><%= translate(locale, "Player volume: ") %></label>
                 <input name="volume" id="volume" oninput="update_value(this);" type="range" min="0" max="100" step="5" value="<%= user.preferences.volume %>">
                 <span class="pure-form-message-inline" id="volume-value"><%= user.preferences.volume %></span>
             </div>
 
             <div class="pure-control-group">
-                <label for="comments_0">Default comments: </label>
+                <label for="comments_0"><%= translate(locale, "Default comments: ") %></label>
                 <select name="comments_0" id="comments_0">
                 <% {"", "youtube", "reddit"}.each do |option| %>
-                    <option <% if user.preferences.comments[0] == option %> selected <% end %>><%= option %></option>
+                    <option value="<%= option %>" <% if user.preferences.comments[0] == option %> selected <% end %>><%= translate(locale, option) %></option>
                 <% end %>
                 </select>
             </div>
 
             <div class="pure-control-group">
-                <label for="comments_1">Fallback comments: </label>
+                <label for="comments_1"><%= translate(locale, "Fallback comments: ") %></label>
                 <select name="comments_1" id="comments_1">
                 <% {"", "youtube", "reddit"}.each do |option| %>
-                    <option <% if user.preferences.comments[1] == option %> selected <% end %>><%= option %></option>
+                    <option value="<%= option %>" <% if user.preferences.comments[1] == option %> selected <% end %>><%= translate(locale, option) %></option>
                 <% end %>
                 </select>
             </div>
 
             <div class="pure-control-group">
-                <label for="captions_0">Default captions: </label>
+                <label for="captions_0"><%= translate(locale, "Default captions: ") %></label>
                 <select class="pure-u-1-5" name="captions_0" id="captions_0">
                 <% CAPTION_LANGUAGES.each do |option| %>
-                    <option <% if user.preferences.captions[0] == option %> selected <% end %>><%= option %></option>
+                    <option value="<%= option %>" <% if user.preferences.captions[0] == option %> selected <% end %>><%= translate(locale, option) %></option>
                 <% end %>
                 </select>
             </div>
 
             <div class="pure-control-group">
-                <label for="captions_fallback">Fallback captions: </label>
+                <label for="captions_fallback"><%= translate(locale, "Fallback captions: ") %></label>
                 <select class="pure-u-1-5" name="captions_1" id="captions_1">
                 <% CAPTION_LANGUAGES.each do |option| %>
-                    <option <% if user.preferences.captions[1] == option %> selected <% end %>><%= option %></option>
+                    <option value="<%= option %>" <% if user.preferences.captions[1] == option %> selected <% end %>><%= translate(locale, option) %></option>
                 <% end %>
                 </select>
 
                 <select class="pure-u-1-5" name="captions_2" id="captions_2">
                 <% CAPTION_LANGUAGES.each do |option| %>
-                    <option <% if user.preferences.captions[2] == option %> selected <% end %>><%= option %></option>
+                    <option value="<%= option %>" <% if user.preferences.captions[2] == option %> selected <% end %>><%= translate(locale, option) %></option>
                 <% end %>
                 </select>
             </div>
 
             <div class="pure-control-group">
-                <label for="related_videos">Show related videos? </label>
+                <label for="related_videos"><%= translate(locale, "Show related videos? ") %></label>
                 <input name="related_videos" id="related_videos" type="checkbox" <% if user.preferences.related_videos %>checked<% end %>>
             </div>
 
-            <legend>Visual preferences</legend>
+            <legend><%= translate(locale, "Visual preferences") %></legend>
 
             <div class="pure-control-group">
-                <label for="dark_mode">Dark mode: </label>
+                <label for="locale"><%= translate(locale, "Language: ") %></label>
+                <select name="locale" id="locale">
+                <% LOCALES.each_key do |option| %>
+                    <option value="<%= option %>" <% if user.preferences.locale == option %> selected <% end %>><%= option %></option>
+                <% end %>
+                </select>
+            </div>
+
+            <div class="pure-control-group">
+                <label for="dark_mode"><%= translate(locale, "Dark mode: ") %></label>
                 <input name="dark_mode" id="dark_mode" type="checkbox" <% if user.preferences.dark_mode %>checked<% end %>>
             </div>
 
             <div class="pure-control-group">
-                <label for="thin_mode">Thin mode: </label>
+                <label for="thin_mode"><%= translate(locale, "Thin mode: ") %></label>
                 <input name="thin_mode" id="thin_mode" type="checkbox" <% if user.preferences.thin_mode %>checked<% end %>>
             </div>
 
-            <legend>Subscription preferences</legend>
+            <legend><%= translate(locale, "Subscription preferences") %></legend>
 
             <div class="pure-control-group">
-                <label for="redirect_feed">Redirect homepage to feed: </label>
+                <label for="redirect_feed"><%= translate(locale, "Redirect homepage to feed: ") %></label>
                 <input name="redirect_feed" id="redirect_feed" type="checkbox" <% if user.preferences.redirect_feed %>checked<% end %>>
             </div>
 
             <div class="pure-control-group">
-                <label for="max_results">Number of videos shown in feed: </label>
+                <label for="max_results"><%= translate(locale, "Number of videos shown in feed: ") %></label>
                 <input name="max_results" id="max_results" type="number" value="<%= user.preferences.max_results %>">
             </div>
 
             <div class="pure-control-group">
-                <label for="sort">Sort videos by: </label>
+                <label for="sort"><%= translate(locale, "Sort videos by: ") %></label>
                 <select name="sort" id="sort">
                 <% {"published", "published - reverse", "alphabetically", "alphabetically - reverse", "channel name", "channel name - reverse"}.each do |option| %>
-                    <option <% if user.preferences.sort == option %> selected <% end %>><%= option %></option>
+                    <option value="<%= option %>" <% if user.preferences.sort == option %> selected <% end %>><%= translate(locale, option) %></option>
                 <% end %>
                 </select>
             </div>
@@ -143,39 +152,39 @@ function update_value(element) {
             </div>
 
             <div class="pure-control-group">
-                <label for="unseen_only">Only show unwatched: </label>
+                <label for="unseen_only"><%= translate(locale, "Only show unwatched: ") %></label>
                 <input name="unseen_only" id="unseen_only" type="checkbox" <% if user.preferences.unseen_only %>checked<% end %>>
             </div>
 
             <div class="pure-control-group">
-                <label for="notifications_only">Only show notifications (if there are any): </label>
+                <label for="notifications_only"><%= translate(locale, "Only show notifications (if there are any): ") %></label>
                 <input name="notifications_only" id="notifications_only" type="checkbox" <% if user.preferences.notifications_only %>checked<% end %>>
             </div>
 
-            <legend>Data preferences</legend>
+            <legend><%= translate(locale, "Data preferences") %></legend>
 
             <div class="pure-control-group">
-                <a href="/clear_watch_history?referer=<%= URI.escape(referer) %>">Clear watch history</a>
+                <a href="/clear_watch_history?referer=<%= URI.escape(referer) %>"><%= translate(locale, "Clear watch history") %></a>
             </div>
             
             <div class="pure-control-group">
-                <a href="/data_control?referer=<%= URI.escape(referer) %>">Import/Export data</a>
+                <a href="/data_control?referer=<%= URI.escape(referer) %>"><%= translate(locale, "Import/Export data") %></a>
             </div>
 
             <div class="pure-control-group">
-                <a href="/subscription_manager">Manage subscriptions</a>
+                <a href="/subscription_manager"><%= translate(locale, "Manage subscriptions") %></a>
             </div>
 
             <div class="pure-control-group">
-                <a href="/feed/history">Watch history</a>
+                <a href="/feed/history"><%= translate(locale, "Watch history") %></a>
             </div>
 
             <div class="pure-control-group">
-                <a href="/delete_account?referer=<%= URI.escape(referer) %>">Delete account</a>
+                <a href="/delete_account?referer=<%= URI.escape(referer) %>"><%= translate(locale, "Delete account") %></a>
             </div>
 
             <div class="pure-controls">
-                <button type="submit" class="pure-button pure-button-primary">Save preferences</button>
+                <button type="submit" class="pure-button pure-button-primary"><%= translate(locale, "Save preferences") %></button>
             </div>
         </fieldset>
     </form>

src/invidious/views/search.ecr

@@ -13,13 +13,17 @@
 <div class="pure-g h-box">
     <div class="pure-u-1 pure-u-md-1-5">
     <% if page >= 2 %>
-        <a href="/search?q=<%= HTML.escape(query.not_nil!) %>&page=<%= page - 1 %>">Previous page</a>
+        <a href="/search?q=<%= HTML.escape(query.not_nil!) %>&page=<%= page - 1 %>">
+            <%= translate(locale, "Previous page") %>
+        </a>
     <% end %>
     </div>
     <div class="pure-u-1 pure-u-md-3-5"></div>
     <div style="text-align:right;" class="pure-u-1 pure-u-md-1-5">
     <% if count >= 20 %>
-        <a href="/search?q=<%= HTML.escape(query.not_nil!) %>&page=<%= page + 1 %>">Next page</a>
+        <a href="/search?q=<%= HTML.escape(query.not_nil!) %>&page=<%= page + 1 %>">
+            <%= translate(locale, "Next page") %>
+        </a>
     <% end %>
     </div>
 </div>

src/invidious/views/subscription_manager.ecr

@@ -1,19 +1,19 @@
 <% content_for "header" do %>
-<title>Subscription manager - Invidious</title>
+<title><%= translate(locale, "Subscription manager") %> - Invidious</title>
 <% end %>
 
 <div class="pure-g h-box">
     <div class="pure-u-1-3">
-        <h3><span id="count"><%= subscriptions.size %></span> subscriptions</h3>
+        <h3><%= translate(locale, "`x` subscriptions", %(<span id="count">#{subscriptions.size}</span>)) %></h3>
     </div>
     <div class="pure-u-1-3" style="text-align:center;">
         <h3>
-            <a href="/feed/history">Watch history</a>
+            <a href="/feed/history"><%= translate(locale, "Watch history") %></a>
         </h3>
     </div>
     <div class="pure-u-1-3" style="text-align:right;">
         <h3>
-            <a href="/data_control?referer=<%= referer %>">Import/Export</a>
+            <a href="/data_control?referer=<%= referer %>"><%= translate(locale, "Import/Export") %></a>
         </h3>
     </div>
 </div>
@@ -33,7 +33,7 @@
                     data-id="<%= channel.id %>"
                     onmouseenter='this["href"]="javascript:void(0)"'
                     href="/subscription_ajax?action_remove_subscriptions=1&c=<%= channel.id %>">
-                    unsubscribe
+                    <%= translate(locale, "unsubscribe") %>
                 </a>
             </h3>
         </div>

src/invidious/views/subscriptions.ecr

@@ -1,16 +1,16 @@
 <% content_for "header" do %>
-<title>Subscriptions - Invidious</title>
+<title><%= translate(locale, "Subscriptions") %> - Invidious</title>
 <% end %>
 
 <div class="pure-g h-box">
     <div class="pure-u-1-3">
         <h3>
-            <a href="/subscription_manager">Manage subscriptions</a>
+            <a href="/subscription_manager"><%= translate(locale, "Manage subscriptions") %></a>
         </h3>
     </div>
     <div class="pure-u-1-3" style="text-align:center;">
         <h3>
-            <a href="/feed/history">Watch history</a>
+            <a href="/feed/history"><%= translate(locale, "Watch history") %></a>
         </h3>
     </div>
     <div class="pure-u-1-3" style="text-align:right;">
@@ -20,7 +20,7 @@
     </div>
 </div>
 
-<center><%= notifications.size %> unseen notifications</center>
+<center><%= translate(locale, "`x` unseen notifications", "#{notifications.size}") %></center>
 
 <% if !notifications.empty? %>
 <div class="h-box">
@@ -73,13 +73,17 @@ function mark_watched(target) {
 <div class="pure-g">
     <div class="pure-u-1 pure-u-md-1-5">
     <% if page >= 2 %>
-        <a href="/feed/subscriptions?max_results=<%= max_results %>&page=<%= page - 1 %>">Previous page</a>
+        <a href="/feed/subscriptions?max_results=<%= max_results %>&page=<%= page - 1 %>">
+            <%= translate(locale, "Previous page") %>
+        </a>
     <% end %>
     </div>
     <div class="pure-u-1 pure-u-md-3-5"></div>
     <div style="text-align:right;" class="pure-u-1 pure-u-md-1-5">
         <% if (videos.size + notifications.size) == max_results %>
-            <a href="/feed/subscriptions?max_results=<%= max_results %>&page=<%= page + 1 %>">Next page</a>
+            <a href="/feed/subscriptions?max_results=<%= max_results %>&page=<%= page + 1 %>">
+                <%= translate(locale, "Next page") %>
+            </a>
         <% end %>
     </div>
 </div>

src/invidious/views/template.ecr

@@ -25,6 +25,8 @@
   <% end %>
 </head>
 
+<% locale = LOCALES[env.get("locale").as(String)]? %>
+
 <body>
   <div class="pure-g">
     <div class="pure-u-1 pure-u-md-2-24"></div>
@@ -68,32 +70,46 @@
           </a>
         </div>
         <div class="pure-u-1-4">
-          <a href="/signout?referer=<%= env.get?("current_page") %>&token=<%= env.get?("token") %>&challenge=<%= env.get?("challenge") %>" class="pure-menu-heading">Sign out</a>
+          <a href="/signout?referer=<%= env.get?("current_page") %>&token=<%= env.get?("token") %>&challenge=<%= env.get?("challenge") %>" class="pure-menu-heading">
+            <%= translate(locale, "Sign out") %>
+          </a>
         </div>
         <% else %>
-          <a href="/login?referer=<%= env.get?("current_page") %>" class="pure-menu-heading">Login</a>
+          <a href="/login?referer=<%= env.get?("current_page") %>" class="pure-menu-heading">
+            <%= translate(locale, "Login") %>
+          </a>
         <% end %>
         </div>
       </div>
       <%= content %>
       <div class="footer">
-        Released under the AGPLv3 by <a href="https://github.com/omarroth">Omar
-          Roth</a>.
-        Source available <a
-          href="https://github.com/omarroth/invidious">here</a>.
-        <p>Liberapay: 
+        <p>
+          <a href="https://github.com/omarroth">
+            <%= translate(locale, "Released under the AGPLv3 by Omar Roth.") %>
+          </a>
+        </p>
+        <p>
+          <a href="https://github.com/omarroth/invidious">
+            <%= translate(locale, "Source available here.") %>
+          </a>
+        </p>
+        <p><%= translate(locale, "Liberapay: ") %>
           <a href="https://liberapay.com/omarroth">
             https://liberapay.com/omarroth
           </a>
         </p>
-        <p>Patreon: 
+        <p><%= translate(locale, "Patreon: ") %>
           <a href="https://patreon.com/omarroth">
             https://patreon.com/omarroth
           </a>
         </p>
-        <p>BTC: 356DpZyMXu6rYd55Yqzjs29n79kGKWcYrY</p>
-        <p>BCH: qq4ptclkzej5eza6a50et5ggc58hxsq5aylqut2npk</p>
-        <p>View <a rel="jslicense" href="/licenses">JavaScript license information</a>.</p>
+        <p><%= translate(locale, "BTC: ") %>356DpZyMXu6rYd55Yqzjs29n79kGKWcYrY</p>
+        <p><%= translate(locale, "BCH: ") %>qq4ptclkzej5eza6a50et5ggc58hxsq5aylqut2npk</p>
+        <p>
+          <a rel="jslicense" href="/licenses">
+            <%= translate(locale, "View JavaScript license information.") %>
+          </a>
+        </p>
       </div>
     </div>
     <div class="pure-u-1 pure-u-md-2-24"></div>

src/invidious/views/top.ecr

@@ -1,3 +1,7 @@
+<% content_for "header" do %>
+<title><%= translate(locale, "Top") %> - Invidious</title>
+<% end %>
+
 <div class="pure-g">
 <% top_videos.each_slice(4) do |slice| %>
         <% slice.each do |item| %>

src/invidious/views/trending.ecr

@@ -1,5 +1,5 @@
 <% content_for "header" do %>
-<title>Trending - Invidious</title>
+<title><%= translate(locale, "Trending") %> - Invidious</title>
 <% end %>
 
 <div class="pure-g">

src/invidious/views/watch.ecr

@@ -52,11 +52,11 @@
 <div class="pure-g">
     <div class="pure-u-1 pure-u-md-1-5">
         <div class="h-box">
-            <p><a href="https://www.youtube.com/watch?v=<%= video.id %>">Watch video on YouTube</a></p>
+            <p><a href="https://www.youtube.com/watch?v=<%= video.id %>"><%= translate(locale, "Watch video on Youtube") %></a></p>
             <p><i class="icon ion-ios-eye"></i> <%= number_with_separator(video.views) %></p>
             <p><i class="icon ion-ios-thumbs-up"></i> <%= number_with_separator(video.likes) %></p>
             <p><i class="icon ion-ios-thumbs-down"></i> <%= number_with_separator(video.dislikes) %></p>
-            <p id="Genre">Genre: 
+            <p id="Genre"><%= translate(locale, "Genre: ") %>
             <% if video.genre_url.empty? %>
             <%= video.genre %>
             <% else %>
@@ -64,18 +64,18 @@
             <% end %>
             </p>
             <% if !video.license.empty? %>
-            <p id="License">License: <%= video.license %></p>
+            <p id="License"><%= translate(locale, "License: ") %><%= video.license %></p>
             <% end %>
-            <p id="FamilyFriendly">Family friendly? <%= video.is_family_friendly %></p>
-            <p id="Wilson">Wilson score: <%= video.wilson_score.round(4) %></p>
-            <p id="Rating">Rating: <%= rating.round(4) %> / 5</p>
-            <p id="Engagement">Engagement: <%= engagement.round(2) %>%</p>
+            <p id="FamilyFriendly"><%= translate(locale, "Family friendly? ") %><%= video.is_family_friendly %></p>
+            <p id="Wilson"><%= translate(locale, "Wilson score: ") %><%= video.wilson_score.round(4) %></p>
+            <p id="Rating"><%= translate(locale, "Rating: ") %><%= rating.round(4) %> / 5</p>
+            <p id="Engagement"><%= translate(locale, "Engagement: ") %><%= engagement.round(2) %>%</p>
             <% if video.allowed_regions.size != REGIONS.size %>
                 <p id="AllowedRegions">
                 <% if video.allowed_regions.size < REGIONS.size / 2 %>
-                Whitelisted regions: <%= video.allowed_regions.join(", ") %>
+                <%= translate(locale, "Whitelisted regions: ") %><%= video.allowed_regions.join(", ") %>
                 <% else %>
-                Blacklisted regions: <%= (REGIONS.to_a - video.allowed_regions).join(", ") %>
+                <%= translate(locale, "Blacklisted regions: ") %><%= (REGIONS.to_a - video.allowed_regions).join(", ") %>
                 <% end %>
                 </p>
             <% end %>
@@ -94,14 +94,14 @@
             <p>
                 <a id="subscribe" onclick="unsubscribe()" class="pure-button pure-button-primary" 
                     href="/subscription_ajax?action_remove_subscriptions=1&c=<%= video.ucid %>&referer=<%= env.get("current_page") %>">
-                    <b>Unsubscribe | <%= video.sub_count_text %></b>
+                    <b><%= translate(locale, "Unsubscribe") %> | <%= video.sub_count_text %></b>
                 </a>
             </p>
             <% else %>
             <p>
                 <a id="subscribe" onclick="subscribe()" class="pure-button pure-button-primary" 
                     href="/subscription_ajax?action_create_subscription_to_channel=1&c=<%= video.ucid %>&referer=<%= env.get("current_page") %>">
-                    <b>Subscribe | <%= video.sub_count_text %></b>
+                    <b><%= translate(locale, "Subscribe") %> | <%= video.sub_count_text %></b>
                 </a>
             </p>
             <% end %>
@@ -109,12 +109,12 @@
             <p>
                 <a id="subscribe" class="pure-button pure-button-primary" 
                     href="/login?referer=<%= env.get("current_page") %>">
-                    <b>Login to subscribe to <%= video.author %></b>
+                    <b><%= translate(locale, "Login to subscribe to `x`", video.author) %></b>
                 </a>
             </p>
         <% end %>
             <p>
-                <b>Shared <%= video.published.to_s("%B %-d, %Y") %></b>
+                <b><%= translate(locale, "Shared `x`", video.published.to_s("%B %-d, %Y")) %></b>
             </p>
             <div>
                 <%= video.description %>
@@ -125,8 +125,9 @@
                     <%= comment_html %>
                 <% else %>
                 <noscript>
-                Hi! Looks like you have JavaScript disabled. Click <a href="/watch?<%= env.params.query %>&nojs=1">here</a> to view
-                comments, keep in mind it may take a bit longer to load.
+                    <a href="/watch?<%= env.params.query %>&nojs=1">
+                        <%= translate(locale, "Hi! Looks like you have JavaScript disabled. Click here to view comments, keep in mind it may take a bit longer to load.") %>
+                    </a>
                 </noscript>
                 <% end %>
             </div>
@@ -145,7 +146,7 @@
         <% if !rvs.empty? %>
         <div id="continue" <% if plid %>style="display:none"<% end %>>
             <div class="pure-control-group">
-                <label for="continue">Autoplay next video: </label>
+                <label for="continue"><%= translate(locale, "Autoplay next video: ") %></label>
                 <input name="continue" onclick="continue_autoplay(this)" id="continue" type="checkbox" <% if params[:continue] %>checked<% end %>>
             </div>
             <hr>
@@ -241,7 +242,7 @@ function subscribe() {
             if (xhr.status == 200) {
                 subscribe_button = document.getElementById("subscribe");
                 subscribe_button.onclick = unsubscribe;
-                subscribe_button.innerHTML = '<b>Unsubscribe | <%= video.sub_count_text %></b>'
+                subscribe_button.innerHTML = '<b><%= translate(locale, "Unsubscribe") %> | <%= video.sub_count_text %></b>'
             }
         }
     }
@@ -260,7 +261,7 @@ function unsubscribe() {
             if (xhr.status == 200) {
                 subscribe_button = document.getElementById("subscribe");
                 subscribe_button.onclick = subscribe;
-                subscribe_button.innerHTML = '<b>Subscribe | <%= video.sub_count_text %></b>'
+                subscribe_button.innerHTML = '<b><%= translate(locale, "Subscribe") %> | <%= video.sub_count_text %></b>'
             }
         }
     }
@@ -276,9 +277,9 @@ function get_playlist() {
     var plid = "<%= plid %>"
 
     if (plid.startsWith("RD")) {
-        var plid_url = "/api/v1/mixes/<%= plid %>?continuation=<%= video.id %>&format=html";
+        var plid_url = "/api/v1/mixes/<%= plid %>?continuation=<%= video.id %>&format=html&hl=<%= env.get("locale").as(String) %>";
     } else {
-        var plid_url = "/api/v1/playlists/<%= plid %>?continuation=<%= video.id %>&format=html";
+        var plid_url = "/api/v1/playlists/<%= plid %>?continuation=<%= video.id %>&format=html&hl=<%= env.get("locale").as(String) %>";
     }
 
     var xhr = new XMLHttpRequest();
@@ -335,7 +336,7 @@ function get_reddit_comments() {
   comments.innerHTML =
     '<h3><center class="loading"><i class="icon ion-ios-refresh"></i></center></h3>';
 
-  var url = "/api/v1/comments/<%= video.id %>?source=reddit&format=html";
+  var url = "/api/v1/comments/<%= video.id %>?source=reddit&format=html&hl=<%= env.get("locale").as(String) %>";
   var xhr = new XMLHttpRequest();
   xhr.responseType = "json";
   xhr.timeout = 20000;
@@ -354,12 +355,12 @@ function get_reddit_comments() {
                 <p> \
                     <b> \
                         <a href="javascript:void(0)" onclick="swap_comments(\'youtube\')"> \
-                            View YouTube comments \
+                            <%= translate(locale, "View YouTube comments") %> \
                         </a> \
                     </b> \
                 </p> \
                 <b> \
-                    <a rel="noopener" target="_blank" href="https://reddit.com{permalink}">View more comments on Reddit</a> \
+                    <a rel="noopener" target="_blank" href="https://reddit.com{permalink}"><%= translate(locale, "View more comments on Reddit") %></a> \
                 </b> \
             </div> \
             <div>{contentHtml}</div> \
@@ -391,7 +392,7 @@ function get_youtube_comments() {
   comments.innerHTML =
     '<h3><center class="loading"><i class="icon ion-ios-refresh"></i></center></h3>';
 
-  var url = "/api/v1/comments/<%= video.id %>?format=html";
+  var url = "/api/v1/comments/<%= video.id %>?format=html&hl=<%= env.get("locale").as(String) %>";
   var xhr = new XMLHttpRequest();
   xhr.responseType = "json";
   xhr.timeout = 20000;
@@ -406,11 +407,11 @@ function get_youtube_comments() {
                 <div> \
                     <h3> \
                         <a href="javascript:void(0)" onclick="toggle_comments(this)">[ - ]</a> \
-                        View {commentCount} comments \
+                        <%= translate(locale, "View `x` comments", "{commentCount}") %>  \
                     </h3> \
                     <b> \
                         <a href="javascript:void(0)" onclick="swap_comments(\'reddit\')"> \
-                            View Reddit comments \
+                            <%= translate(locale, "View Reddit comments") %> \
                         </a> \
                     </b> \
                 </div> \
@@ -449,7 +450,7 @@ function get_youtube_replies(target, load_more) {
   body.innerHTML =
       '<h3><center class="loading"><i class="icon ion-ios-refresh"></i></center></h3>';
 
-  var url = '/api/v1/comments/<%= video.id %>?format=html&continuation=' +
+  var url = '/api/v1/comments/<%= video.id %>?format=html&hl=<%= env.get("locale").as(String) %>&continuation=' +
       continuation;
   var xhr = new XMLHttpRequest();
   xhr.responseType = 'json';
@@ -467,7 +468,7 @@ function get_youtube_replies(target, load_more) {
         } else {
             body.innerHTML = ' \
                 <p><a href="javascript:void(0)" \
-                    onclick="hide_youtube_replies(this)">Hide replies \
+                    onclick="hide_youtube_replies(this)"><%= translate(locale, "Hide replies") %> \
                 </a></p> \
                 <div>{contentHtml}</div>'.supplant({
                 contentHtml: xhr.response.contentHtml,