python代码playwright库 上传文件并监控进度

以下是使用Playwright库上传文件并监控进度的示例代码：

import asyncio
from playwright.async_api import Playwright, async_playwright

async def file_upload_example(playwright: Playwright) -> None:
    # Launch the browser
    browser = await playwright.chromium.launch()
    page = await browser.new_page()

    # Navigate to a page with a file upload element
    await page.goto("https://www.example.com")

    # Define a coroutine to monitor the upload progress
    async def monitor_upload_progress():
        # Wait for the upload progress bar to appear
        progress_bar = await page.wait_for_selector("#upload-progress-bar")

        # Monitor the progress until the upload is complete
        while not await progress_bar.is_hidden():
            # Get the current progress value
            progress_value = await progress_bar.get_attribute("value")

            # Do something with the progress value (e.g. update a progress bar)
            print(f"Upload progress: {progress_value}%")

            # Wait for the progress bar to update
            await page.wait_for_timeout(1000)

    # Start monitoring the upload progress in the background
    progress_task = asyncio.create_task(monitor_upload_progress())

    # Upload a file
    file_input = await page.query_selector("#file-upload-input")
    await file_input.set_input_files("./example.txt")
    await page.click("#upload-button")

    # Wait for the upload to complete
    await page.wait_for_selector("#upload-complete")

    # Stop monitoring the upload progress
    progress_task.cancel()

    # Close the browser
    await browser.close()

# Run the example
with async_playwright() as playwright:
    asyncio.run(file_upload_example(playwright))

该示例使用Playwright库启动一个Chromium浏览器实例，并在页面上找到一个文件上传元素。当用户选择文件并单击上传按钮时，浏览器将开始上传文件并显示一个进度条。`monitor_upload_progress()`函数会在后台监控上传进度，并将进度信息输出到控制台。一旦上传完成，页面将显示一个上传完成的消息。然后，该示例会关闭浏览器。

请注意，`monitor_upload_progress()`函数是一个异步协程，因此必须使用`asyncio.create_task()`函数将其作为任务运行。示例中使用了`progress_task.cancel()`函数来停止监视进度的任务，以确保在上传完成后立即停止监视进度。