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InsightRadar/backend/app/services/fetcher_service.py
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stardrophere e28b893a12 optimize
2026-03-12 01:50:08 +08:00

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Python

# app/services/fetcher_service.py
import os
import hashlib
from datetime import timedelta
import httpx
import json
import numpy as np
from dotenv import load_dotenv
from sklearn.metrics.pairwise import cosine_similarity
from sentence_transformers import SentenceTransformer
from app.database import SessionLocal
from app.models.models import (
InfoSource, TrendingEvent, NewsArticle, DataSyncTask, TaskStatus,
HeadlineRevision, RankingLog, SourceType, utcnow, UnifiedEvent
)
# 加载环境变量
load_dotenv()
hf_token = os.getenv("HF_TOKEN")
SIMILARITY_THRESHOLD = float(os.getenv("SIMILARITY_THRESHOLD", 0.72))
API_BASE_URL = os.getenv("API_BASE_URL", "https://newsnow.busiyi.world/api/s")
EMBEDDING_MODEL_PATH = os.getenv("EMBEDDING_MODEL_PATH", "")
print("正在加载 BAAI/bge-m3 向量模型...")
# 全局单例
embedder_model = SentenceTransformer(EMBEDDING_MODEL_PATH, local_files_only=True, device="cuda")
print("模型加载完成。")
def generate_md5(text: str) -> str:
"""生成32位MD5哈希值作为全局唯一指纹"""
return hashlib.md5(text.encode('utf-8')).hexdigest()
def generate_embedding_json(text: str) -> str:
"""辅助函数:调用大模型生成向量,并序列化为 JSON 字符串"""
raw_vec = embedder_model.encode([text], normalize_embeddings=True, show_progress_bar=False)[0]
truncated_vec = [round(float(x), 5) for x in raw_vec]
return json.dumps(truncated_vec, separators=(',', ':'))
def match_or_create_unified_event(db, title: str, embedding_json: str) -> int:
"""
辅助函数:大事件聚类中枢。
拿着新计算的向量去数据库里碰,碰到了就返回老 ID,碰不到就建新的。
"""
# 提取刚算出来的向量
new_vec = np.array(json.loads(embedding_json))
# 只取最近 3 天的活跃大事件进行比对
three_days_ago = utcnow() - timedelta(days=3)
recent_events = db.query(UnifiedEvent).filter(
UnifiedEvent.created_at >= three_days_ago
).order_by(UnifiedEvent.created_at.desc()).limit(200).all()
if recent_events:
valid_events = [ev for ev in recent_events if ev.center_embedding]
if valid_events:
event_vectors = [json.loads(ev.center_embedding) for ev in valid_events]
# 批量矩阵计算相似度
sim_scores = cosine_similarity([new_vec], event_vectors)[0]
max_idx = np.argmax(sim_scores)
if sim_scores[max_idx] >= SIMILARITY_THRESHOLD:
matched_event = valid_events[max_idx]
matched_event.hot_score += 1
return matched_event.id
# 没匹配到,创建一个新的统一大事件
new_unified = UnifiedEvent(
unified_title=title,
center_embedding=embedding_json,
hot_score=1 # 初始热度
)
db.add(new_unified)
db.flush() # 获取自增的主键 ID
return new_unified.id
def process_hot_trend_item(db, source, item, index: int, external_id: str):
"""
处理【热搜/短新闻】的业务逻辑,现已加入 AI 聚类功能
"""
title = item.get("title")
item_url = item.get("url", "")
existing_event = db.query(TrendingEvent).filter(
TrendingEvent.source_id == source.id,
TrendingEvent.external_id == external_id
).first()
event_to_log = None
# 核心逻辑:查重后再决定是否调用模型
if existing_event:
# 场景 A1:老熟人
if existing_event.current_headline != title:
# 标题被暗改,此时需要重新算一次 Embedding
new_embedding_json = generate_embedding_json(title)
revision = HeadlineRevision(
event_id=existing_event.id,
previous_headline=existing_event.current_headline,
revised_headline=title
)
db.add(revision)
existing_event.current_headline = title
existing_event.title_embedding = new_embedding_json # 更新为新标题的语义向量
# 注:这里不改变它所属的 unified_event_id,因为大体还是同一件事
existing_event.current_ranking = index
existing_event.event_url = item_url
event_to_log = existing_event
else:
# 场景 A2:这是一条彻底的全新热搜
# 1. 计算向量
new_embedding_json = generate_embedding_json(title)
# 2. 扔进聚类中枢找归宿
matched_event_id = match_or_create_unified_event(db, title, new_embedding_json)
# 3. 落库
new_event = TrendingEvent(
source_id=source.id,
external_id=external_id,
current_headline=title,
event_url=item_url,
current_ranking=index,
title_embedding=new_embedding_json, # 存入向量
unified_event_id=matched_event_id # 挂载到大事件下
)
db.add(new_event)
db.flush()
event_to_log = new_event
# 强制记录排名轨迹
rank_log = RankingLog(
event_id=event_to_log.id,
ranking_position=index
)
db.add(rank_log)
def process_rss_feed_item(db, source, item, external_id: str):
"""
处理【长文章/传统订阅】分支的核心业务逻辑 (写入 NewsArticle 表)
"""
title = item.get("title")
item_url = item.get("url", "")
existing_article = db.query(NewsArticle).filter(
NewsArticle.source_id == source.id,
NewsArticle.external_id == external_id
).first()
if existing_article:
# 文章若存在,仅更新基础字段
existing_article.article_title = title
existing_article.article_url = item_url
else:
# 全新文章入库
new_article = NewsArticle(
source_id=source.id,
external_id=external_id,
article_title=title,
article_url=item_url,
)
db.add(new_article)
def process_source_data(db, source, items: list) -> int:
"""
数据清洗与路由分发层:
遍历 API 返回的 items,生成唯一指纹,并路由到不同的处理模块。
返回成功处理的条目数量。
"""
saved_count = 0
platform_id = source.home_url
for index, item in enumerate(items, 1):
title = item.get("title")
if not title:
continue
item_url = item.get("url", "")
# ID 兜底策略:接口ID -> URL -> Title
raw_id = item.get("id") or item_url or title
external_id = generate_md5(f"{platform_id}_{raw_id}")
# 核心路由分流
if source.source_type in (SourceType.HOT_TREND, SourceType.API):
process_hot_trend_item(db, source, item, index, external_id)
elif source.source_type == SourceType.RSS_FEED:
process_rss_feed_item(db, source, item, external_id)
saved_count += 1
return saved_count
async def fetch_and_save_trending_data():
"""
调度层:负责网络请求、数据库事务管理和异常监控隔离。
"""
print(f"[{utcnow()}] 开始执行定时抓取任务...")
with SessionLocal() as db:
# 获取启用的信息源
sources = db.query(InfoSource).filter(InfoSource.is_enabled == True).all()
if not sources:
print("没有找到启用的信息源,任务结束。")
return
# 伪装请求头,规避反爬
custom_headers = {
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36",
"Accept": "application/json, text/plain, */*",
"Referer": "https://newsnow.busiyi.world/",
"Origin": "https://newsnow.busiyi.world"
}
async with httpx.AsyncClient(timeout=15.0, headers=custom_headers) as client:
for source in sources:
platform_id = source.home_url
if not platform_id:
continue
url = f"{API_BASE_URL}?id={platform_id}&latest"
# 初始化监控日志
task_log = DataSyncTask(source_id=source.id, items_fetched=0)
try:
# 发起网络请求
response = await client.get(url)
response.raise_for_status()
data_json = response.json()
items = data_json.get("items", [])
# 调用数据处理层
saved_count = process_source_data(db, source, items)
# 业务事务成功提交
task_log.items_fetched = saved_count
task_log.task_status = TaskStatus.SUCCESS
db.add(task_log)
db.commit()
print(f"[{source.source_name}] ({source.source_type}) 成功抓取并更新了 {saved_count} 条数据")
except Exception as e:
# 异常拦截与错误隔离
db.rollback()
task_log.task_status = TaskStatus.ERROR
task_log.error_trace = str(e)
db.add(task_log)
db.commit()
print(f"[{source.source_name}] 抓取失败: {e}")