diff --git a/spec/invidious/helpers_spec.cr b/spec/invidious/helpers_spec.cr
index 9fbb6d6fe..6908bf7c3 100644
--- a/spec/invidious/helpers_spec.cr
+++ b/spec/invidious/helpers_spec.cr
@@ -3,6 +3,36 @@ 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 #music))
+ end
+
+ it "links hashtags after punctuation" do
+ expect(parse_video_title("Watch: #music"))
+ .to eq(%(Watch: #music))
+ end
+
+ it "does not link hashes inside words" do
+ expect(parse_video_title("Video title test#music"))
+ .to eq("Video title test#music")
+ end
+
+ it "encodes unicode hashtags" do
+ hashtag = "\u{4E2D}\u{6587}"
+ punctuation = "\u{FF0C}"
+
+ expect(parse_video_title("Video ##{hashtag}#{punctuation}"))
+ .to eq(%(Video ##{hashtag}#{punctuation}))
+ end
+
+ it "escapes video titles before linking hashtags" do
+ expect(parse_video_title(%(#music & #news)))
+ .to eq(%(<b>#music</b> & #news))
+ 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")
diff --git a/src/invidious/helpers/utils.cr b/src/invidious/helpers/utils.cr
index 7a262f849..69efd1bf3 100644
--- a/src/invidious/helpers/utils.cr
+++ b/src/invidious/helpers/utils.cr
@@ -20,6 +20,50 @@ def elapsed_text(elapsed)
"#{(millis * 1000).round(2)}µs"
end
+def parse_video_title(title : String) : String
+ title_chars = title.chars
+
+ return String.build(title.size) do |str|
+ index = 0
+
+ while index < title_chars.size
+ char = title_chars[index]
+
+ if char == '#' && video_title_hashtag_start?(title_chars, index)
+ hashtag_end = index + 1
+
+ while hashtag_end < title_chars.size && video_title_hashtag_char?(title_chars[hashtag_end])
+ hashtag_end += 1
+ end
+
+ hashtag = title_chars[(index + 1)...hashtag_end].join
+ url = URI.encode_path("/hashtag/#{hashtag}")
+
+ str << %()
+ str << HTML.escape("##{hashtag}")
+ str << ""
+
+ index = hashtag_end
+ else
+ str << HTML.escape(char.to_s)
+ index += 1
+ end
+ end
+ end
+end
+
+private def video_title_hashtag_start?(title_chars : Array(Char), index : Int) : Bool
+ next_char = title_chars[index + 1]?
+ return false if next_char.nil?
+ return false unless video_title_hashtag_char?(next_char)
+
+ index == 0 || !video_title_hashtag_char?(title_chars[index - 1])
+end
+
+private def video_title_hashtag_char?(char : Char) : Bool
+ char == '_' || char.alphanumeric?
+end
+
def decode_length_seconds(string)
length_seconds = string.gsub(/[^0-9:]/, "")
return 0_i32 if length_seconds.empty?
diff --git a/src/invidious/views/watch.ecr b/src/invidious/views/watch.ecr
index 796c0c914..ee393e7de 100644
--- a/src/invidious/views/watch.ecr
+++ b/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.