Add youtube duplicate detection (#1174)

app/models/story.rb

@@ -237,6 +237,28 @@ class Story < ApplicationRecord
       urls = urls2.uniq
     end
 
+    # www.youtube.com
+    # m.youtube.com
+    # youtube.com          redirects to www.youtube.com
+    # youtu.be             redirects to www.youtube.com
+    # www.m.youtube.com    doesn't work
+    # www.youtu.be         doesn't exist
+    # m.youtu.be           doesn't exist
+    if /^https?:\/\/((?:www\d*|m)\.)?(youtube\.com|youtu\.be)/i.match(url)
+      urls.each do |u|
+        id = /^https?:\/\/(?:(?:m|www)\.)?(?:youtube\.com\/watch\?v=|youtu\.be\/)([A-z0-9\-_]+)/i
+          .match(u)[1]
+
+        urls2.push "https://www.youtube.com/watch?v=#{id}"
+        # In theory, youtube redirects https://youtube.com to https://www.youtube.com
+        # let's check it just in case
+        urls2.push "https://youtube.com/watch?v=#{id}"
+        urls2.push "https://youtu.be/#{id}"
+        urls2.push "https://m.youtube.com/watch?v=#{id}"
+      end
+      urls = urls2.uniq
+    end
+
     # https
     urls.each do |u|
       urls2.push u.gsub(/^http:\/\//i, "https://")

spec/models/story_spec.rb

@@ -327,6 +327,28 @@ describe Story do
       expect(s1.similar_stories).to eq([s2])
       expect(s2.similar_stories).to eq([s1])
     end
+
+    it "finds similar www.youtube and youtu.be URLs" do
+      s1 = create(:story,
+                  url: 'https://www.youtube.com/watch?v=7Pq-S557XQU',
+                  created_at: (Story::RECENT_DAYS + 1).days.ago)
+
+      s2 = create(:story, url: 'https://youtu.be/7Pq-S557XQU')
+
+      expect(s1.similar_stories).to eq([s2])
+      expect(s2.similar_stories).to eq([s1])
+    end
+
+    it "finds similar www.youtube and m.youtube URLs" do
+      s1 = create(:story,
+                  url: 'https://www.youtube.com/watch?v=7Pq-S557XQU',
+                  created_at: (Story::RECENT_DAYS + 1).days.ago)
+
+      s2 = create(:story, url: 'https://m.youtube.com/watch?v=7Pq-S557XQU')
+
+      expect(s1.similar_stories).to eq([s2])
+      expect(s2.similar_stories).to eq([s1])
+    end
   end
 
   describe "#calculated_hotness" do