2nd/10_Wiki/Topics/Backend/comment_harvester.md

---
id: wiki-2026-0508-comment-harvester
title: comment_harvester (YouTube/Reddit Comment Scraper)
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [Comment Scraper, Comment Pipeline, Social Comment ETL]
duplicate_of: none
source_trust_level: A
confidence_score: 0.85
verification_status: applied
tags: [scraping, youtube-api, reddit-api, etl, sentiment, llm-pipeline]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: Python 3.12 / TypeScript
  framework: yt-dlp + YouTube Data API v3 / PRAW / DuckDB
---

# comment_harvester (YouTube/Reddit Comment Scraper)

## 매 한 줄
> **"매 YouTube/Reddit/etc 의 comment 를 매 paginated API 로 fetch → normalize → store, 그리고 매 LLM 의 batch sentiment/topic extraction 으로 enrich 하는 매 pipeline"**. 2026 표준 stack: yt-dlp/YT-DATA-API + PRAW + DuckDB + Claude/GPT batch API. 매 use case: market research, content idea mining, brand monitoring.

## 매 핵심

### 매 Source matrix
| Platform | Auth | Rate limit | Library |
|---|---|---|---|
| YouTube | OAuth/API key | 10k units/day default | google-api-python-client, yt-dlp |
| Reddit | OAuth (PRAW) | 100 req/min | praw, asyncpraw |
| Twitter/X | API tier (paid) | varies | tweepy |
| TikTok | unofficial | volatile | TikTokApi |
| Instagram | private API | very volatile | instagrapi |

### 매 Pipeline 단계
1. **Source resolve**: video URL/ID, subreddit, channel.
2. **Fetch**: paginated, with `nextPageToken` / `after`.
3. **Normalize**: `{ id, parentId, author, text, ts, likes, replies, sourceMeta }`.
4. **Dedupe + store**: DuckDB / Postgres.
5. **Enrich**: LLM batch (sentiment, topic, language, toxicity).
6. **Serve**: SQL / Streamlit / API.

### 매 Ethical / legal
- 매 Public comments only. Robots.txt + ToS respect.
- 매 PII redact (email, phone in text).
- GDPR: deletion 의 honor.
- 매 commercial use 의 platform-specific 제약 — 매 read carefully.

### 매 응용
1. Channel-level sentiment trend (매 video 마다).
2. Topic clustering (Claude embedding + UMAP + HDBSCAN).
3. Auto-FAQ from creator's recurring questions.
4. Competitor brand mention.

## 💻 패턴

### YouTube Data API v3
```python
from googleapiclient.discovery import build
import os

yt = build('youtube', 'v3', developerKey=os.environ['YT_KEY'])

def fetch_comments(video_id: str, max_pages=100):
    page_token = None
    for _ in range(max_pages):
        resp = yt.commentThreads().list(
            part='snippet,replies', videoId=video_id,
            maxResults=100, pageToken=page_token, textFormat='plainText',
        ).execute()
        for item in resp['items']:
            top = item['snippet']['topLevelComment']['snippet']
            yield {
                'id': item['id'],
                'parent_id': None,
                'author': top['authorDisplayName'],
                'text': top['textDisplay'],
                'ts': top['publishedAt'],
                'likes': top['likeCount'],
            }
            for r in item.get('replies', {}).get('comments', []):
                rs = r['snippet']
                yield {'id': r['id'], 'parent_id': item['id'],
                       'author': rs['authorDisplayName'], 'text': rs['textDisplay'],
                       'ts': rs['publishedAt'], 'likes': rs['likeCount']}
        page_token = resp.get('nextPageToken')
        if not page_token: break
```

### Reddit (asyncpraw)
```python
import asyncpraw, asyncio

async def fetch_subreddit(name: str, limit=200):
    reddit = asyncpraw.Reddit(client_id=..., client_secret=..., user_agent='harvester/1.0')
    sub = await reddit.subreddit(name)
    async for submission in sub.new(limit=limit):
        await submission.comments.replace_more(limit=0)
        for c in submission.comments.list():
            yield {'id': c.id, 'parent_id': c.parent_id, 'author': str(c.author),
                   'text': c.body, 'ts': c.created_utc, 'likes': c.score,
                   'submission_id': submission.id}
```

### DuckDB sink
```python
import duckdb
con = duckdb.connect('comments.db')
con.execute("""
CREATE TABLE IF NOT EXISTS comments(
  id VARCHAR PRIMARY KEY, parent_id VARCHAR, source VARCHAR,
  source_id VARCHAR, author VARCHAR, text VARCHAR,
  ts TIMESTAMP, likes INT, lang VARCHAR, sentiment FLOAT, topic VARCHAR
);
""")
def upsert(rows):
    con.executemany(
        "INSERT OR REPLACE INTO comments(id,parent_id,source,source_id,author,text,ts,likes) VALUES (?,?,?,?,?,?,?,?)",
        rows,
    )
```

### LLM batch enrich (Claude Message Batches)
```python
from anthropic import Anthropic
client = Anthropic()

requests = [{
    "custom_id": row['id'],
    "params": {
        "model": "claude-opus-4-7",
        "max_tokens": 200,
        "messages": [{"role": "user", "content":
            f"Output JSON {{lang, sentiment(-1..1), topic(<=3 words)}} for: {row['text']}"}],
    },
} for row in batch]

batch = client.messages.batches.create(requests=requests)
# poll batch.id until completed, then parse results
```

### Incremental cron
```python
# crontab: 0 */6 * * *
import sys, datetime as dt
last = con.execute("SELECT max(ts) FROM comments WHERE source='yt' AND source_id=?", [vid]).fetchone()[0]
since = last or dt.datetime.utcnow() - dt.timedelta(days=30)
for c in fetch_comments(vid):
    if dt.datetime.fromisoformat(c['ts'].rstrip('Z')) <= since: break
    upsert([(c['id'], c['parent_id'], 'yt', vid, c['author'], c['text'], c['ts'], c['likes'])])
```

### Topic clustering
```python
from anthropic import Anthropic
import umap, hdbscan, numpy as np
client = Anthropic()

texts = [r[0] for r in con.execute("SELECT text FROM comments WHERE topic IS NULL LIMIT 5000").fetchall()]
embeds = []  # 매 embedding API 또는 voyage-3
proj = umap.UMAP(n_components=10, metric='cosine').fit_transform(np.array(embeds))
labels = hdbscan.HDBSCAN(min_cluster_size=20).fit_predict(proj)
```

## 매 결정 기준
| 상황 | Approach |
|---|---|
| ≤ 100 videos / day | YT Data API + key (free quota) |
| Heavy crawl | yt-dlp `--write-comments` (no API quota, but slower) |
| Reddit live monitor | PRAW streaming `subreddit.stream.comments()` |
| Storage | DuckDB (single-node analytics), Postgres (multi-tenant) |
| Enrichment cost | Claude Batch (50% off) > realtime API |
| Real-time alert | Reddit stream + Slack webhook |

**기본값**: YT Data API + DuckDB + Claude Batch enrichment + 6h incremental cron.

## 🔗 Graph
- 변형: [[my_videos_check]] · [[WebHooks_and_Notifications|telegram_notify]]
- 응용: [[Sentiment-Analysis]]
- Adjacent: [[DuckDB]]

## 🤖 LLM 활용
**언제**: pipeline scaffold, normalization schema, batch prompt design.
**언제 X**: ToS / legal review — 매 platform-specific lawyer 의 read.

## ❌ 안티패턴
- **No rate-limit handling**: 매 quota 의 burn → 매 24h ban.
- **Storing raw text without dedupe**: 매 storage explode + double-enrich cost.
- **Realtime LLM per comment**: cost 의 50× higher than batch.
- **Ignoring deleted-comment lifecycle**: stale data + GDPR violation.
- **API key in code**: 매 .env + secret manager.

## 🧪 검증 / 중복
- Verified (YouTube Data API v3, PRAW 7.7+, Claude Message Batches docs).
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — comment harvest pipeline + LLM enrichment |