backend/app/services/crawler/browser.py

"""
Playwright browser management with stealth for Janus crawler.
"""

import asyncio
import logging
import random
from typing import Optional

logger = logging.getLogger(__name__)

USER_AGENTS = [
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2 Safari/605.1.15",
    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
]

STEALTH_SCRIPTS = [
    """
    Object.defineProperty(navigator, 'webdriver', { get: () => undefined });
    """,
    """
    window.chrome = { runtime: {} };
    """,
    """
    Object.defineProperty(navigator, 'languages', { get: () => ['en-US', 'en'] });
    """,
    """
    Object.defineProperty(navigator, 'plugins', { get: () => [1, 2, 3, 4, 5] });
    """,
]


class BrowserManager:
    """Manages Playwright browser lifecycle with stealth."""

    def __init__(self):
        self._browser = None
        self._context = None
        self._playwright = None

    async def __aenter__(self):
        await self.launch()
        return self

    async def __aexit__(self, exc_type, exc_val, exc_tb):
        await self.close()

    async def launch(self):
        """Launch browser with stealth configuration."""
        try:
            from playwright.async_api import async_playwright
        except ImportError:
            logger.error(
                "Playwright not installed. Run: pip install playwright && playwright install"
            )
            raise

        try:
            self._playwright = await async_playwright().start()
            self._browser = await self._playwright.chromium.launch(
                headless=True,
                args=[
                    "--disable-blink-features=AutomationControlled",
                    "--no-sandbox",
                    "--disable-dev-shm-usage",
                ],
            )
        except Exception as e:
            logger.error(
                "Playwright browser launch failed. Install browser binaries with: playwright install chromium (%s)",
                e,
            )
            if self._playwright:
                await self._playwright.stop()
                self._playwright = None
            raise

        ua = random.choice(USER_AGENTS)
        self._context = await self._browser.new_context(
            user_agent=ua,
            viewport={"width": 1920, "height": 1080},
            locale="en-US",
        )

        for script in STEALTH_SCRIPTS:
            await self._context.add_init_script(script)

        logger.debug("Browser launched with stealth")

    async def get_page(self):
        """Get a new page from the browser context."""
        if not self._context:
            await self.launch()
        return await self._context.new_page()

    async def close(self):
        """Clean up browser resources."""
        try:
            if self._context:
                await self._context.close()
            if self._browser:
                await self._browser.close()
            if self._playwright:
                await self._playwright.stop()
            logger.debug("Browser closed")
        except Exception as e:
            logger.warning(f"Error closing browser: {e}")