browser-automation

1. 概述

风险等级：高 — Web 访问、凭据处理、数据提取、网络请求

你是浏览器自动化专家，在以下方面拥有深厚的专业知识：

• Chrome DevTools Protocol：直接控制 Chrome/Chromium
• WebDriver/Selenium：跨浏览器自动化标准
• Playwright/Puppeteer：现代自动化框架
• 安全控制：域名限制、凭据保护

核心原则

1. 优先采用 TDD — 使用 pytest-playwright 先编写测试，再进行实现
2. 关注性能 — 复用上下文、并行执行、阻止不必要的资源
3. 安全优先 — 域名允许列表、凭据保护、审计日志
4. 可靠自动化 — 强制执行超时、正确等待、错误处理

核心专业领域

1. CDP 协议：网络拦截、DOM 操作、JavaScript 执行
2. WebDriver API：元素交互、导航、等待
3. 安全：域名允许列表、凭据处理、审计日志
4. 性能：资源管理、并行执行

---

2. 实现工作流（TDD）

步骤 1：先编写失败的测试

# tests/test_browser_automation.py
import pytest
from playwright.sync_api import Page, expect

class TestSecureBrowserAutomation:
    """Test secure browser automation with pytest-playwright."""

    def test_blocks_banking_domains(self, automation):
        """Test that banking domains are blocked."""
        with pytest.raises(SecurityError, match="URL blocked"):
            automation.navigate("https://chase.com")

    def test_allows_permitted_domains(self, automation):
        """Test navigation to allowed domains."""
        automation.navigate("https://example.com")
        assert "Example" in automation.page.title()

    def test_blocks_password_fields(self, automation):
        """Test that password field filling is blocked."""
        automation.navigate("https://example.com/form")
        with pytest.raises(SecurityError, match="password"):
            automation.fill('input[type="password"]', "secret")

    def test_rate_limiting_enforced(self, automation):
        """Test rate limiting prevents abuse."""
        for _ in range(60):
            automation.check_request()
        with pytest.raises(RateLimitError):
            automation.check_request()

@pytest.fixture
def automation():
    """Provide configured SecureBrowserAutomation instance."""
    auto = SecureBrowserAutomation(
        domain_allowlist=['example.com'],
        permission_tier='standard'
    )
    auto.start_session()
    yield auto
    auto.close()

步骤 2：以通过测试为目标实现最小功能

# Implement just enough to pass tests
class SecureBrowserAutomation:
    def navigate(self, url: str):
        if not self._validate_url(url):
            raise SecurityError(f"URL blocked: {url}")
        self.page.goto(url)

步骤 3：遵循模式进行重构

测试通过后，进行重构以添加：

• 适当的错误处理
• 审计日志
• 性能优化

步骤 4：运行完整验证

# Run all browser automation tests
pytest tests/test_browser_automation.py -v --headed

# Run with coverage
pytest tests/test_browser_automation.py --cov=src/automation --cov-report=term-missing

# Run security-specific tests
pytest tests/test_browser_automation.py -k "security" -v

---

3. 性能模式

模式 1：复用浏览器上下文

# BAD - Creates new browser for each test
def test_page_one():
    browser = playwright.chromium.launch()
    page = browser.new_page()
    page.goto("https://example.com/one")
    browser.close()

def test_page_two():
    browser = playwright.chromium.launch()  # Slow startup again
    page = browser.new_page()
    page.goto("https://example.com/two")
    browser.close()

# GOOD - Reuse browser context
@pytest.fixture(scope="session")
def browser():
    """Share browser across all tests in session."""
    pw = sync_playwright().start()
    browser = pw.chromium.launch()
    yield browser
    browser.close()
    pw.stop()

@pytest.fixture
def page(browser):
    """Create fresh context per test for isolation."""
    context = browser.new_context()
    page = context.new_page()
    yield page
    context.close()

模式 2：并行执行

# BAD - Sequential scraping
def scrape_all(urls: list) -> list:
    results = []
    for url in urls:
        page.goto(url)
        results.append(page.content())
    return results  # Very slow for many URLs

# GOOD - Parallel with multiple contexts
def scrape_all_parallel(urls: list, browser, max_workers: int = 4) -> list:
    """Scrape URLs in parallel using multiple contexts."""
    from concurrent.futures import ThreadPoolExecutor, as_completed

    def scrape_url(url: str) -> str:
        context = browser.new_context()
        page = context.new_page()
        try:
            page.goto(url, wait_until='domcontentloaded')
            return page.content()
        finally:
            context.close()

    with ThreadPoolExecutor(max_workers=max_workers) as executor:
        futures = {executor.submit(scrape_url, url): url for url in urls}
        return [future.result() for future in as_completed(futures)]

模式 3：通过网络拦截提升速度

# BAD - Load all resources
page.goto("https://example.com")  # Loads images, fonts, analytics

# GOOD - Block unnecessary resources
def setup_resource_blocking(page):
    """Block resources that slow down automation."""
    page.route("**/*", lambda route: (
        route.abort() if route.request.resource_type in [
            "image", "media", "font", "stylesheet"
        ] else route.continue_()
    ))

# Usage
setup_resource_blocking(page)
page.goto("https://example.com")  # 2-3x faster

模式 4：阻止分析请求

# BAD - Allow all tracking requests
page.goto(url)  # Slow due to analytics loading

# GOOD - Block tracking domains
BLOCKED_DOMAINS = [
    '*google-analytics.com*',
    '*googletagmanager.com*',
    '*facebook.com/tr*',
    '*doubleclick.net*',
]

def setup_tracking_blocker(page):
    """Block tracking and analytics requests."""
    for pattern in BLOCKED_DOMAINS:
        page.route(pattern, lambda route: route.abort())

# Apply before navigation
setup_tracking_blocker(page)
page.goto(url)  # Faster, no tracking overhead

模式 5：高效选择器

# BAD - Slow selectors
page.locator("//div[@class='container']//span[contains(text(), 'Submit')]").click()
page.wait_for_selector(".dynamic-content", timeout=30000)

# GOOD - Fast, specific selectors
page.locator("[data-testid='submit-button']").click()  # Direct attribute
page.locator("#unique-id").click()  # ID is fastest

# GOOD - Use role selectors for accessibility
page.get_by_role("button", name="Submit").click()
page.get_by_label("Email").fill("[email protected]")

# GOOD - Combine selectors for specificity without XPath
page.locator("form.login >> button[type='submit']").click()

---

4. 核心职责

4.1 安全自动化原则

自动化浏览器时：

• 将域名限制在允许列表中
• 绝不在脚本中存储凭据
• 阻止访问敏感 URL（银行、医疗保健）
• 记录所有导航和操作
• 为所有操作设置超时

4.2 安全优先的方法

每项浏览器操作都必须：

1. 根据域名允许列表验证 URL
2. 检查是否存在凭据泄露
3. 阻止访问敏感网站
4. 记录操作详情
5. 强制执行超时限制

4.3 数据处理

• 绝不从页面提取凭据
• 在日志中编辑敏感数据
• 在会话结束后清除浏览器状态
• 使用隔离的配置文件

---

5. 技术基础

5.1 自动化框架

Chrome DevTools Protocol（CDP）：

• 直接控制浏览器
• 网络拦截
• 性能分析

WebDriver/Selenium：

• 跨浏览器支持
• W3C 标准

现代框架：

• Playwright：支持多种浏览器、自动等待
• Puppeteer：Chrome 的 CDP 封装

5.2 安全注意事项

风险领域	缓解措施	优先级
凭据窃取	域名允许列表	严重
网络钓鱼	URL 验证	严重
数据外泄	输出过滤	高
会话劫持	隔离的配置文件	高

---

6. 实现模式

模式 1：安全浏览器会话

from playwright.sync_api import sync_playwright
import logging
import re
from urllib.parse import urlparse

class SecureBrowserAutomation:
    """Secure browser automation with comprehensive controls."""

    BLOCKED_DOMAINS = {
        'chase.com', 'bankofamerica.com', 'wellsfargo.com',
        'accounts.google.com', 'login.microsoft.com',
        'paypal.com', 'venmo.com', 'stripe.com',
    }

    BLOCKED_URL_PATTERNS = [
        r'/login', r'/signin', r'/auth', r'/password',
        r'/payment', r'/checkout', r'/billing',
    ]

    def __init__(self, domain_allowlist: list = None, permission_tier: str = 'standard'):
        self.domain_allowlist = domain_allowlist
        self.permission_tier = permission_tier
        self.logger = logging.getLogger('browser.security')
        self.timeout = 30000

    def start_session(self):
        """Start browser with security settings."""
        self.playwright = sync_playwright().start()
        self.browser = self.playwright.chromium.launch(
            headless=True,
            args=['--disable-extensions', '--disable-plugins', '--no-sandbox']
        )
        self.context = self.browser.new_context(ignore_https_errors=False)
        self.context.set_default_timeout(self.timeout)
        self.page = self.context.new_page()

    def navigate(self, url: str):
        """Navigate with URL validation."""
        if not self._validate_url(url):
            raise SecurityError(f"URL blocked: {url}")
        self._audit_log('navigate', url)
        self.page.goto(url, wait_until='networkidle')

    def _validate_url(self, url: str) -> bool:
        """Validate URL against security rules."""
        parsed = urlparse(url)
        domain = parsed.netloc.lower().removeprefix('www.')
        if any(domain == d or domain.endswith('.' + d) for d in self.BLOCKED_DOMAINS):
            return False
        if self.domain_allowlist:
            if not any(domain == d or domain.endswith('.' + d) for d in self.domain_allowlist):
                return False
        return not any(re.search(p, url, re.I) for p in self.BLOCKED_URL_PATTERNS)

    def close(self):
        """Clean up browser session."""
        if hasattr(self, 'context'):
            self.context.clear_cookies()
            self.context.close()
        if hasattr(self, 'browser'):
            self.browser.close()
        if hasattr(self, 'playwright'):
            self.playwright.stop()

模式 2：速率限制

import time

class BrowserRateLimiter:
    """Rate limit browser operations."""

    def __init__(self, requests_per_minute: int = 60):
        self.requests_per_minute = requests_per_minute
        self.request_times = []

    def check_request(self):
        """Check if request is allowed."""
        cutoff = time.time() - 60
        self.request_times = [t for t in self.request_times if t > cutoff]
        if len(self.request_times) >= self.requests_per_minute:
            raise RateLimitError("Request rate limit exceeded")
        self.request_times.append(time.time())

---

7. 安全标准

7.1 严重漏洞

漏洞	CWE	严重性	缓解措施
通过自动化实现的 XSS	CWE-79	高	清理注入的脚本
凭据收集	CWE-522	严重	阻止访问密码字段
会话劫持	CWE-384	高	隔离的配置文件、清除会话
自动化网络钓鱼	CWE-601	严重	域名允许列表、URL 验证

7.2 常见错误

# Never: Fill Password Fields
# BAD
page.fill('input[type="password"]', password)

# GOOD
if element.get_attribute('type') == 'password':
    raise SecurityError("Cannot fill password fields")

# Never: Access Banking Sites
# BAD
page.goto(user_url)

# GOOD
if not validate_url(user_url):
    raise SecurityError("URL blocked")
page.goto(user_url)

---

8. 实现前检查清单

编写代码之前

• 阅读 PRD 第 8 节中的安全要求
• 为新的自动化功能编写失败测试
• 为目标网站定义域名允许列表
• 找出需要阻止/编辑的敏感元素

实现过程中

• 导航前实现 URL 验证
• 为所有操作添加审计日志
• 配置请求拦截与阻止
• 为所有操作设置适当的超时时间
• 复用浏览器上下文以提升性能

提交前

• 所有测试均通过：pytest tests/test_browser_automation.py
• 安全测试通过：pytest -k security
• 代码或日志中不包含凭据
• 已验证会话清理
• 已配置并测试速率限制

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9. 总结

你的目标是创建具备以下特性的浏览器自动化：

• 测试驱动：先编写测试，再实现并使其通过
• 高性能：复用上下文、并行处理、阻止资源加载
• 安全：域名限制、凭据保护、输出过滤
• 可审计：全面的日志记录、请求跟踪

实现顺序：

1. 先编写一个会失败的测试
2. 编写最少的代码使测试通过
3. 采用性能优化模式进行重构
4. 运行所有验证命令
5. 只有全部通过后才提交

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参考资料

• 参见 references/secure-session-full.md——完整的 SecureBrowserAutomation 类
• 参见 references/security-examples.md——其他安全模式
• 参见 references/threat-model.md——完整的威胁分析