---
phase: 08-crawler
plan: 03
subsystem: crawler
tags: [proxy, rate-limiter, retry, anti-crawl, playwright]

requires:
  - phase: 08-01
    provides: ZhihuCrawler base class
provides:
  - CrawlerConfig for proxy/rate limiting configuration
  - Random delay (1-3s) between requests
  - Exponential backoff retry (3 attempts)
  - Automatic x-zse-96 signature handling via browser

tech-stack:
  added:
    - tenacity (retry library)
  patterns:
    - Environment variable proxy configuration
    - Exponential backoff retry pattern
    - Random delay for rate limiting

key-files:
  created:
    - kb_workflow/crawler/config.py
    - tests/test_crawler/test_proxy_config.py
    - tests/test_crawler/test_rate_limiter.py
    - tests/test_crawler/test_api_intercept.py
  modified:
    - kb_workflow/crawler/zhihu_crawler.py
    - kb_workflow/crawler/models.py
    - tests/test_crawler/test_comment_crawler.py
key-decisions:
  - Mandatory proxy configuration (configurable via proxy_required flag)
  - Use tenacity library for retry with exponential backoff
  - x-zse-96 signature handled automatically by browser via route.fetch()
  - Random delay range: 1-3 seconds (configurable)
requirements-completed: [NET-01, NET-02, NET-03]
duration: 15min
completed: 2026-03-17
---

## Summary

实现了网络反爬措施：强制代理配置、请求频率控制、有限重试机制，以及利用浏览器自动处理 x-zse-96 签名。

### What Was Built

**CrawlerConfig 类** (`kb_workflow/crawler/config.py`)
- `ProxyConfig` - 代理配置模型
- 从环境变量 `HTTP_PROXY`/`HTTPS_PROXY` 读取代理设置
- `proxy_required` 标志控制是否强制代理（默认 `True`）
- 随机延迟配置（`min_delay`, `max_delay`）
- 重试配置（`max_retries`, `retry_min_wait`, `retry_max_wait`）

**ZhihuCrawler 增强**
- `_start_browser_with_proxy()` - 启动浏览器并应用代理配置
- `_apply_random_delay()` - 应用随机延迟（1-3 秒）
- `_crawl_with_retry()` - 带指数退避的重试逻辑
- 浏览器自动处理 x-zse-96 签名（通过 `route.fetch()`）

### Test Coverage

**44 个测试全部通过**
- `test_proxy_config.py` - 11 个代理配置测试
- `test_rate_limiter.py` - 8 个频率控制测试
- `test_api_intercept.py` - 4 个 API 拦截测试
- 其他测试文件保持通过

### Commits

1. `626fb73` feat(08-03): create CrawlerConfig for proxy and rate limiting
2. `9e1452d` feat(08-03): integrate proxy, delay, and retry into ZhihuCrawler

### Key Decisions

1. **强制代理**: 默认 `proxy_required=True`，未配置代理时抛出 `ValueError`
2. **重试机制**: 使用 `tenacity` 库，最多 3 次重试，间隔指数递增（2s → 10s）
3. **签名处理**: 利用浏览器 `route.fetch()` 自动携带 x-zse-96 签名，无需手动逆向

### Requirements Completed

- **NET-01**: 用户可以通过环境变量配置代理 IP ✓
- **NET-02**: 不配置代理时，爬虫拒绝运行并提示错误 ✓
- **NET-03**: 每次请求间有随机延迟（1-3秒），失败重试 3 次 ✓

## Self-Check: PASSED