feat(web): parse YouTube video id from pasted URL forms

Pure parser for watch?v=, youtu.be/, shorts/, embed/, and bare ids; rejects non-YouTube hosts and malformed input. Foundation for paste-a-URL summarize (Feature 2). No fetch, no gate interaction — parsing only. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-09 21:35:05 +02:00
parent e4c701c6f1
commit bddd75d92e
2 changed files with 119 additions and 0 deletions
@@ -0,0 +1,57 @@
+package web
+
+import "testing"
+
+func TestParseYouTubeVideoID(t *testing.T) {
+	const id = "dQw4w9WgXcQ"
+	ok := []struct {
+		name, in string
+	}{
+		{"watch", "https://www.youtube.com/watch?v=" + id},
+		{"watch no www", "https://youtube.com/watch?v=" + id},
+		{"watch m", "https://m.youtube.com/watch?v=" + id},
+		{"watch extra params", "https://www.youtube.com/watch?v=" + id + "&t=42s&list=PLxyz"},
+		{"watch param after", "https://www.youtube.com/watch?list=PLxyz&v=" + id},
+		{"short link", "https://youtu.be/" + id},
+		{"short link param", "https://youtu.be/" + id + "?si=abcd&t=1"},
+		{"shorts", "https://www.youtube.com/shorts/" + id},
+		{"embed", "https://www.youtube.com/embed/" + id},
+		{"bare id", id},
+		{"http scheme", "http://youtube.com/watch?v=" + id},
+		{"no scheme", "youtube.com/watch?v=" + id},
+		{"trailing space", "  https://youtu.be/" + id + "  "},
+	}
+	for _, c := range ok {
+		t.Run(c.name, func(t *testing.T) {
+			got, err := parseYouTubeVideoID(c.in)
+			if err != nil {
+				t.Fatalf("parseYouTubeVideoID(%q) error: %v", c.in, err)
+			}
+			if got != id {
+				t.Fatalf("parseYouTubeVideoID(%q) = %q, want %q", c.in, got, id)
+			}
+		})
+	}
+
+	bad := []struct {
+		name, in string
+	}{
+		{"empty", ""},
+		{"blank", "   "},
+		{"vimeo", "https://vimeo.com/123456789"},
+		{"other host", "https://example.com/watch?v=" + id},
+		{"watch no id", "https://www.youtube.com/watch?v="},
+		{"short id", "https://youtu.be/abc"},
+		{"long id", "https://youtu.be/" + id + "extra"},
+		{"bad chars", "https://youtu.be/dQw4w9Wg!cQ"},
+		{"not a url", "just some text"},
+		{"channel url", "https://www.youtube.com/@somechannel"},
+	}
+	for _, c := range bad {
+		t.Run("reject "+c.name, func(t *testing.T) {
+			if got, err := parseYouTubeVideoID(c.in); err == nil {
+				t.Fatalf("parseYouTubeVideoID(%q) = %q, want error", c.in, got)
+			}
+		})
+	}
+}