Fix: [2.0.2] yt-dlp → youtube-transcript-api로 교체

OCI 서버에서 YouTube 봇 감지로 yt-dlp 차단됨.
자막 전용 라이브러리로 교체하여 클라우드 IP 환경에서도 동작하도록 수정.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/transcript.py

@@ -1,5 +1,4 @@
-import httpx
-import yt_dlp
+from youtube_transcript_api import YouTubeTranscriptApi
 
 
 def extract_video_id(url: str) -> str:
@@ -12,44 +11,9 @@ def extract_video_id(url: str) -> str:
 
 
 def fetch_transcript(video_id: str) -> str:
-    """yt-dlp로 YouTube 자동생성 자막을 텍스트로 추출."""
-    url = f"https://www.youtube.com/watch?v={video_id}"
-
-    ydl_opts = {
-        "skip_download": True,
-        "writeautomaticsub": True,
-        "subtitleslangs": ["ko", "en"],
-        "subtitlesformat": "json3",
-        "quiet": True,
-        "no_warnings": True,
-    }
-
-    with yt_dlp.YoutubeDL(ydl_opts) as ydl:
-        info = ydl.extract_info(url, download=False)
-
-    subs = info.get("automatic_captions", {})
-    lang = "ko" if "ko" in subs else "en" if "en" in subs else None
-    if not lang:
-        raise ValueError(f"자막을 찾을 수 없습니다: {video_id}")
-
-    sub_url = None
-    for fmt in subs[lang]:
-        if fmt["ext"] == "json3":
-            sub_url = fmt["url"]
-            break
-
-    if not sub_url:
-        raise ValueError(f"json3 자막 포맷을 찾을 수 없습니다: {video_id}")
-
-    resp = httpx.get(sub_url)
-    resp.raise_for_status()
-    data = resp.json()
-
-    texts = []
-    for event in data.get("events", []):
-        for seg in event.get("segs", []):
-            text = seg.get("utf8", "").strip()
-            if text and text != "\n":
-                texts.append(text)
+    """YouTube 자막을 텍스트로 추출."""
+    ytt_api = YouTubeTranscriptApi()
+    transcript = ytt_api.fetch(video_id, languages=["ko", "en"])
 
+    texts = [entry.text for entry in transcript if entry.text.strip()]
     return " ".join(texts)

requirements.txt

@@ -1,6 +1,6 @@
 fastapi==0.115.12
 uvicorn==0.34.2
-yt-dlp>=2025.3.31
+youtube-transcript-api==1.0.3
 anthropic==0.52.0
 httpx==0.28.1
 pydantic-settings==2.8.1