Link hashtags in video titles

spec/invidious/helpers_spec.cr

@@ -3,6 +3,16 @@ require "../spec_helper"
 CONFIG = Config.from_yaml(File.open("config/config.example.yml"))
 
 Spectator.describe "Helper" do
+  describe "#parse_video_title" do
+    it "links hashtags in video titles" do
+      expect(parse_video_title("Video title #music")).to eq(%(Video title <a href="/hashtag/music">#music</a>))
+    end
+
+    it "escapes video titles before linking hashtags" do
+      expect(parse_video_title(%(<b>#music</b>))).to eq(%(&lt;b&gt;<a href="/hashtag/music">#music</a>&lt;/b&gt;))
+    end
+  end
+
   describe "#produce_channel_search_continuation" do
     it "correctly produces token for searching a specific channel" do
       expect(produce_channel_search_continuation("UCXuqSBlHAE6Xw-yeJA0Tunw", "", 100)).to eq("4qmFsgJqEhhVQ1h1cVNCbEhBRTZYdy15ZUpBMFR1bncaIEVnWnpaV0Z5WTJnd0FUZ0JZQUY2QkVkS2IxaTRBUUE9WgCaAilicm93c2UtZmVlZFVDWHVxU0JsSEFFNlh3LXllSkEwVHVud3NlYXJjaA%3D%3D")

src/invidious/helpers/utils.cr

@@ -20,6 +20,14 @@ def elapsed_text(elapsed)
   "#{(millis * 1000).round(2)}µs"
 end
 
+def parse_video_title(title : String) : String
+  HTML.escape(title).gsub(/(^|[[:space:]])#([A-Za-z0-9_]+)/) do |match|
+    prefix = match.starts_with?("#") ? "" : match[0].to_s
+    hashtag = match[prefix.size + 1..]
+    "#{prefix}<a href=\"/hashtag/#{URI.encode_path(hashtag)}\">##{hashtag}</a>"
+  end
+end
+
 def decode_length_seconds(string)
   length_seconds = string.gsub(/[^0-9:]/, "")
   return 0_i32 if length_seconds.empty?

src/invidious/views/watch.ecr

@@ -1,5 +1,6 @@
 <% ucid = video.ucid %>
 <% title = HTML.escape(video.title) %>
+<% title_html = parse_video_title(video.title) %>
 <% author = HTML.escape(video.author) %>
 
 
@@ -77,7 +78,7 @@ we're going to need to do it here in order to allow for translations.
 
 <div class="h-box">
     <h1>
-        <%= title %>
+        <%= title_html %>
         <% if params.listen %>
             <a title="<%=I18n.translate(locale, "Video mode")%>" id="link-iv-listen" data-base-url="/watch?<%= env.params.query %>&listen=0" href="/watch?<%= env.params.query %>&listen=0">
                 <i class="icon ion-ios-videocam"></i>