[Bug]: Cross-platform import fail leads to blocked terminal

[bobrossthebest]

crawl4ai version

0.8.0

Expected Behavior

While in a crawl run, use 'q' to quit the loop gracefully. Also, not throw errors if code is not ran on Linux.

Current Behavior

1. Terminal is blocked, the only way to stop the crawl run in to Ctrl-C, leading to plenty of errors being displayed.
2. At the beginning of any crawl run, an import error is thrown.

Same issue as this bug from another project, which was linked in this bug in your repo

Is this reproducible?

Yes

Inputs Causing the Bug

- Windows Machine
- arun_many function from AsyncWebCrawler
- Default browser config, headless and verbose.
- Run config cache_mode = CacheMode.BYPASS, stream=False

Steps to Reproduce

1. Create a function that uses AsyncWebCrawler.arun_many()
2. Run that function on a non-Linux machine

Code snippets

from crawl4ai import BrowserConfig, CrawlerRunConfig, CacheMode, MemoryAdaptiveDispatcher, CrawlerMonitor, AsyncWebCrawler
import asyncio

async def crawl_list(urls_list: list) -> None:
    browser_config = BrowserConfig(headless=True, verbose=False)
    run_config = CrawlerRunConfig(
        cache_mode=CacheMode.BYPASS,
        stream=False  # Default: get all results at once
    )
    
    dispatcher = MemoryAdaptiveDispatcher(
        memory_threshold_percent=70.0,
        check_interval=1.0,
        max_session_permit=10,
        monitor=CrawlerMonitor(enable_ui=True)
    )
    
    async with AsyncWebCrawler(config=browser_config) as crawler:
        results = await crawler.arun_many(
            urls=urls_list,
            config=run_config,
            dispatcher=dispatcher
        )

if __name__ == "__main__":
    urls_list = ['https://www.google.com', 'https://www.live.com']
    asyncio.run(crawl_list(urls_list))

OS

Windows

Python version

3.12.10

Browser

Default (Chromium?)

Browser version

Default (idk dude)

Error logs & Screenshots (if applicable)

(When pressing Ctrl-C to quit)

[Ahmed-Tawfik94]

Root cause analysis
The issue report describes a Windows 3.12.10 + crawl4ai 0.8.0 setup where AsyncWebCrawler.arun_many() with MemoryAdaptiveDispatcher(monitor=CrawlerMonitor(enable_ui=True)) throws an import error and leaves the terminal “blocked,” so the crawl only stops via Ctrl‑C, not q. (github.com)
The UI thread in crawler_monitor.py (lines 61-99) hard‑imports termios, tty, and uses select.select on sys.stdin plus termios.tcgetattr(sys.stdin), which are Unix‑only assumptions. On Windows, these imports/operations fail, so the key listener never starts, and q can’t be detected. (github.com)
Fix plan
Add platform/TTY guards in TerminalUI._ui_loop (crawler_monitor.py (lines 61-99)): if sys.platform is Windows or sys.stdin.isatty() is false, skip Unix‑specific setup and use a compatible path.
Implement a Windows key listener with msvcrt.kbhit()/getch() (pattern already exists in browser_profiler.py) and use the Unix path only when termios/tty/select are available.
Wrap terminal setup in try/except so import/TTY errors degrade cleanly (log once, keep UI alive without key input, or auto‑disable UI), and always restore terminal settings.
Optional: add enable_ui="auto" or internal auto‑disable for non‑TTY contexts (IDEs, redirected stdin).
Validate on Windows (PowerShell + CMD), macOS/Linux, and non‑TTY runs to confirm q works where supported and UI degrades cleanly otherwise.