Pypeter以PDF格式打印空白列表，而不是完整文档

Question

我正在使用

Django=3.1
pyppeteer=0.2.5 #for printing page as PDF

我不知道问题出在哪里，因为它以前工作得很好。
我正在使用Django的新功能进行异步响应。也许这就是问题所在

打印PDF的代码

async def generate_pdf(request, pk=None, blueprint=''):
    browser = await launch(
        executablePath='/usr/bin/chromium-browser',
        headless=True,
        args=['--no-sandbox'],
        handleSIGINT=False,
        handleSIGTERM=False,
        handleSIGHUP=False
    )
    page = await browser.newPage()
    url = 'https://{}/reports/{}/{}/'.format(request.get_host(), pk, blueprint)
    await page.goto(url, {'waitUntil': 'networkidle0', 'timeout': 60 * 1000})
    pdf_file = await page.pdf({
        "width": "210mm",
        "height": "297mm",
        "printBackground": True,
    })
    await browser.close()

    response = HttpResponse(content_type='application/pdf')
    report_name = await get_report_name(pk)
    response['Content-Disposition'] = 'attachment; filename="{report_name}.pdf"'.format(
        report_name=escape_uri_path(report_name)
    )
    response.write(pdf_file)
    return response

执行上述代码后的uwsgi日志

unhandled exception during loop shutdown
task: <Task finished coro=<WebSocketCommonProtocol.transfer_data() done, defined at /var/www/evaluation360/env/lib/python3.6/site-packages/websockets/protocol.py:818> exception=CancelledError()>
Traceback (most recent call last):
  File "/var/www/evaluation360/env/lib/python3.6/site-packages/websockets/protocol.py", line 700, in close
    loop=self.loop if sys.version_info[:2] < (3, 8) else None,
  File "/usr/lib/python3.6/asyncio/tasks.py", line 358, in wait_for
    return fut.result()
  File "/var/www/evaluation360/env/lib/python3.6/site-packages/websockets/protocol.py", line 1169, in close_connection
    await self.transfer_data_task
concurrent.futures._base.CancelledError
[pid: 1788|app: 0|req: 7/17] 109.63.253.81 () {44 vars in 1002 bytes} [Thu Jul 29 20:00:12 2021] GET /api/v1/reports/617dd17b-217a-4489-aa5f-c7f5568a569b/pdf/test/ => generated 887 bytes in 7326 msecs (HTTP/1.1 200) 8 headers in 537 bytes (2 switches on core 0)