331 lines
10 KiB
Python
331 lines
10 KiB
Python
"""Playwright 页面抓取工具。
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对外暴露三个动作：
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- open_page(url, wait_ms): 打开页面，返回 page_id
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- query(page_id, selector): 选中节点并提取文字、图片 URL 与属性
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- close_page(page_id): 关闭页面，释放浏览器上下文
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实现上内部常驻一个 Browser；每次 open_page 创建独立 BrowserContext 和 Page。
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Playwright 用 async API 跑在一个后台事件循环线程里，多个调用方线程可以真正并发
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（页面加载彼此重叠，不会互相排队）；外层 API 仍保持同步。
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"""
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from __future__ import annotations
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import asyncio
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import atexit
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import threading
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import uuid
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from collections.abc import Coroutine
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from dataclasses import dataclass
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from typing import Any
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from playwright.async_api import Browser, BrowserContext, Page, async_playwright
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# 页面打开超时（毫秒）
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_GOTO_TIMEOUT = 30000
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@dataclass
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class NodeSnapshot:
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"""页面节点快照。"""
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tag: str
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text: str
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image_urls: list[str]
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attrs: dict[str, str]
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@dataclass
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class _PageSession:
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context: BrowserContext
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page: Page
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# 节点提取脚本：取标签名、可见文字、图片地址（含懒加载）与全部属性
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_EXTRACT_JS = r"""(elements) => elements.map((el) => {
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const attrs = {};
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for (const attr of Array.from(el.attributes || [])) {
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attrs[attr.name] = attr.value;
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}
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const imageUrls = [];
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const addImageUrl = (url) => {
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if (!url) return;
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try {
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const absUrl = new URL(url, location.href).href;
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if (
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absUrl.startsWith('data:') ||
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absUrl.startsWith('blob:') ||
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absUrl === 'about:blank'
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) {
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return;
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}
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imageUrls.push(absUrl);
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} catch {
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if (
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url.startsWith('data:') ||
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url.startsWith('blob:') ||
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url === 'about:blank'
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) {
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return;
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}
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imageUrls.push(url);
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}
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};
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const resolveImageUrl = (img) => {
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const candidates = [
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img.getAttribute('data-src'),
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img.getAttribute('data-original'),
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img.getAttribute('data-croporisrc'),
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img.currentSrc,
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img.src,
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img.getAttribute('src'),
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];
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const srcset = img.getAttribute('srcset');
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if (srcset) {
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for (const part of srcset.split(',')) {
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const candidate = part.trim().split(/\s+/)[0];
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candidates.push(candidate);
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}
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}
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for (const candidate of candidates) {
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if (!candidate) continue;
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if (
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candidate.startsWith('data:') ||
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candidate.startsWith('blob:') ||
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candidate === 'about:blank'
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) {
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continue;
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}
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try {
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const absUrl = new URL(candidate, location.href).href;
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if (
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absUrl.startsWith('data:') ||
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absUrl.startsWith('blob:') ||
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absUrl === 'about:blank'
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) {
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continue;
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}
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return absUrl;
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} catch {
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return candidate;
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}
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}
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return null;
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};
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if (el.tagName === 'IMG') {
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addImageUrl(resolveImageUrl(el));
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}
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for (const img of Array.from(el.querySelectorAll('img'))) {
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addImageUrl(resolveImageUrl(img));
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}
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const text = (el.innerText || el.textContent || '').trim();
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return {
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tag: (el.tagName || '').toLowerCase(),
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text,
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image_urls: Array.from(new Set(imageUrls)),
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attrs,
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};
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})"""
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class _BrowserRuntime:
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"""在后台事件循环线程中管理 Playwright 生命周期。
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所有 Playwright 调用都以协程形式提交到同一个事件循环，
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因此多个业务线程的页面操作可以并发交叠执行。
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"""
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def __init__(self) -> None:
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self._thread: threading.Thread | None = None
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self._loop: asyncio.AbstractEventLoop | None = None
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self._launch_lock: asyncio.Lock | None = None
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self._ready = threading.Event()
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self._lock = threading.RLock()
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self._playwright: Any = None
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self._browser: Browser | None = None
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self._pages: dict[str, _PageSession] = {}
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atexit.register(self.close)
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# ──────────── 事件循环线程 ────────────
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def _thread_main(self) -> None:
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loop = asyncio.new_event_loop()
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asyncio.set_event_loop(loop)
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self._loop = loop
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# 在循环所属线程内创建，避免多协程各自新建锁
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self._launch_lock = asyncio.Lock()
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self._ready.set()
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try:
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loop.run_forever()
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finally:
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loop.close()
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def _ensure_loop(self) -> asyncio.AbstractEventLoop:
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with self._lock:
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if self._thread is None or not self._thread.is_alive():
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self._ready.clear()
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self._thread = threading.Thread(
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target=self._thread_main,
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name="offerpie-playwright",
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daemon=True,
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)
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self._thread.start()
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self._ready.wait()
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loop = self._loop
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if loop is None:
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raise RuntimeError("Browser runtime loop is not ready.")
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return loop
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def _submit(self, coro: Coroutine[Any, Any, Any]) -> Any:
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"""把协程提交到事件循环并同步等待结果。"""
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loop = self._ensure_loop()
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return asyncio.run_coroutine_threadsafe(coro, loop).result()
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# ──────────── Playwright 操作 ────────────
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async def _ensure_browser(self) -> Browser:
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if self._browser is not None:
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return self._browser
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assert self._launch_lock is not None
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async with self._launch_lock:
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if self._browser is None:
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self._playwright = await async_playwright().start()
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self._browser = await self._playwright.chromium.launch(headless=True)
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return self._browser
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async def _open_page_impl(self, url: str, wait_ms: int) -> str:
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browser = await self._ensure_browser()
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context = await browser.new_context()
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page = await context.new_page()
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try:
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await page.goto(url, wait_until="domcontentloaded", timeout=_GOTO_TIMEOUT)
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if wait_ms > 0:
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await page.wait_for_timeout(wait_ms)
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except BaseException:
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# 打开失败也要释放上下文，避免泄漏
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await self._dispose(context, page)
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raise
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page_id = uuid.uuid4().hex
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self._pages[page_id] = _PageSession(context=context, page=page)
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return page_id
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async def _query_impl(self, page_id: str, selector: str) -> list[NodeSnapshot]:
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session = self._pages.get(page_id)
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if session is None:
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raise KeyError(f"Unknown page_id: {page_id}")
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locator = session.page.locator(selector)
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payload = await locator.evaluate_all(_EXTRACT_JS)
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return [
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NodeSnapshot(
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tag=item.get("tag", ""),
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text=item.get("text", ""),
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image_urls=list(item.get("image_urls", [])),
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attrs=dict(item.get("attrs", {})),
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)
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for item in payload
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]
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@staticmethod
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async def _dispose(context: BrowserContext, page: Page | None) -> None:
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if page is not None:
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try:
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await page.close()
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except Exception:
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pass
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try:
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await context.close()
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except Exception:
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pass
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async def _close_page_impl(self, page_id: str) -> None:
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session = self._pages.pop(page_id, None)
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if session is None:
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return
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await self._dispose(session.context, session.page)
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async def _shutdown_impl(self) -> None:
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for page_id in list(self._pages):
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await self._close_page_impl(page_id)
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if self._browser is not None:
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try:
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await self._browser.close()
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except Exception:
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pass
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self._browser = None
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if self._playwright is not None:
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try:
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await self._playwright.stop()
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except Exception:
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pass
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self._playwright = None
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# ──────────── 生命周期 ────────────
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def close(self) -> None:
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"""关闭全部页面与浏览器，停止事件循环。"""
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with self._lock:
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thread = self._thread
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loop = self._loop
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if thread is None or not thread.is_alive() or loop is None:
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return
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try:
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asyncio.run_coroutine_threadsafe(
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self._shutdown_impl(), loop
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).result(timeout=15)
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except Exception:
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pass
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loop.call_soon_threadsafe(loop.stop)
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thread.join(timeout=10)
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self._thread = None
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self._loop = None
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self._launch_lock = None
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_runtime = _BrowserRuntime()
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def open_page(url: str, wait_ms: int = 8000) -> str:
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"""打开页面并返回 page_id。"""
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return _runtime._submit(_runtime._open_page_impl(url, wait_ms))
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def query(page_id: str, selector: str) -> list[NodeSnapshot]:
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"""按选择器抓取节点，提取文本、图片 URL 与属性。"""
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items = _runtime._submit(_runtime._query_impl(page_id, selector))
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seen_urls: set[str] = set()
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for item in items:
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unique_urls: list[str] = []
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for url in item.image_urls:
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if url in seen_urls:
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continue
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seen_urls.add(url)
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unique_urls.append(url)
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item.image_urls = unique_urls
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return items
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def close_page(page_id: str) -> None:
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"""关闭页面，释放对应的浏览器上下文。"""
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_runtime._submit(_runtime._close_page_impl(page_id))
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