{"record":{"id":"c2ee4f4a2e16a34a","repo":"unclecode/crawl4ai","slug":"this-function-must-be-run-in-google-colab-environm","errorCode":null,"errorMessage":"This function must be run in Google Colab environment.","messagePattern":"This function must be run in Google Colab environment\\.","errorType":"exception","errorClass":"RuntimeError","httpStatus":null,"severity":"error","filePath":"crawl4ai/utils.py","lineNumber":3240,"sourceCode":"            \n        return result\n    \n    except Exception as e:\n        # Fallback for parsing errors\n        return html_content[:max_size] if len(html_content) > max_size else html_content    \n\ndef start_colab_display_server():\n    \"\"\"\n    Start virtual display server in Google Colab.\n    Raises error if not running in Colab environment.\n    \"\"\"\n    # Check if running in Google Colab\n    try:\n        import google.colab\n        from google.colab import output\n        from IPython.display import IFrame, display\n    except ImportError:\n        raise RuntimeError(\"This function must be run in Google Colab environment.\")\n    \n    import os, time, subprocess\n    \n    os.environ[\"DISPLAY\"] = \":99\"\n    \n    # Xvfb\n    xvfb = subprocess.Popen([\"Xvfb\", \":99\", \"-screen\", \"0\", \"1280x720x24\"])\n    time.sleep(2)\n    \n    # minimal window manager\n    fluxbox = subprocess.Popen([\"fluxbox\"])\n    \n    # VNC → X\n    x11vnc = subprocess.Popen([\"x11vnc\",\n                              \"-display\", \":99\",\n                              \"-nopw\", \"-forever\", \"-shared\",\n                              \"-rfbport\", \"5900\", \"-quiet\"])\n    ","sourceCodeStart":3222,"sourceCodeEnd":3258,"githubUrl":"https://github.com/unclecode/crawl4ai/blob/7e801521428ee12509994d39151006f64055ebe3/crawl4ai/utils.py#L3222-L3258","documentation":"start_colab_display_server (crawl4ai/utils.py:3240) raises RuntimeError when `import google.colab` fails, i.e. the function — which starts an Xvfb virtual display plus fluxbox inside a Colab VM so headless-browser previews can render — is executed outside Google Colab. The check is purely import-based: any normal Linux/macOS/Windows Python process lacks the google.colab module and gets this error.","triggerScenarios":"Calling crawl4ai's Colab display-server helper (used to embed interactive browser output in a Colab notebook) from a local Jupyter notebook, a script, or CI; calling it in Colab after google-colab package was uninstalled or in a kernel where the package is not on sys.path.","commonSituations":"Copying a Colab tutorial notebook and running it locally; trying to get a live preview of the browser during crawling outside Colab; environment where 'google-colab' pip package is absent.","solutions":["Run the notebook inside Google Colab if you need this helper.","Outside Colab, skip the helper and use the standard headless crawl (AsyncWebcrawler with default BrowserConfig) — no virtual display is required.","For a local interactive preview, start Xvfb/fluxbox yourself (or run in a desktop environment) and set DISPLAY manually.","pip install google-colab only if you truly replicate the Colab environment (rarely worth it)."],"exampleFix":"# before\nfrom crawl4ai.utils import start_colab_display_server\nstart_colab_display_server()  # RuntimeError locally\n\n# after\nimport sys\nif \"google.colab\" in sys.modules:\n    from crawl4ai.utils import start_colab_display_server\n    start_colab_display_server()\nelse:\n    async with AsyncWebcrawler() as crawler:\n        result = await crawler.arun(\"https://example.com\")","handlingStrategy":"validation","validationCode":"import sys\n\ndef in_colab() -> bool:\n    return \"google.colab\" in sys.modules or _colab_importable()\n\ndef _colab_importable() -> bool:\n    try:\n        import google.colab  # noqa\n        return True\n    except ImportError:\n        return False\n\n# if not in_colab(): skip start_colab_display_server()","typeGuard":null,"tryCatchPattern":"try:\n    start_colab_display_server()\nexcept RuntimeError as e:\n    if \"Colab\" in str(e):\n        logger.info(\"Skipping display server outside Colab\")\n    else:\n        raise","preventionTips":["Gate Colab-only helpers behind an environment check","Use headless AsyncWebcrawler outside Colab — no virtual display needed"],"tags":["environment","colab","virtual-display","crawl4ai"],"backgroundTag":null,"analyzedSha":"7e801521428ee12509994d39151006f64055ebe3","analyzedAt":"2026-08-14T20:46:20.673Z","schemaVersion":2},"datasetVersion":"2026-08-15T17:31:12.345Z"}