繁体   English   中英

如何在多线程环境中使用requests-html呈现异步页面?

[英]How to render asynchronous page with requests-html in a multithreaded environment?

为了为具有动态加载内容的页面创建一个抓取器, requests-html提供了在JS执行后获取呈现页面的模块。 但是,当尝试通过在多线程实现中调用arender()方法来使用AsyncHTMLSession ,生成的HTML不会更改。

例如,在源代码中提供的URL中,表的HTML值默认情况下为空,并且在脚本执行后,通过arender()方法进行仿真,尽管未注意到任何明显的变化,但仍希望将这些值插入标记中。源代码。

from pprint import pprint

#from bs4 import BeautifulSoup
import asyncio
from timeit import default_timer
from concurrent.futures import ThreadPoolExecutor

from requests_html import AsyncHTMLSession, HTML

async def fetch(session, url):
    r = await session.get(url)
    await r.html.arender()
    return r.content

def parseWebpage(page):
    print(page)

async def get_data_asynchronous():  
    urls = [
        'http://www.fpb.pt/fpb2014/!site.go?s=1&show=jog&id=258215'
    ]  

    with ThreadPoolExecutor(max_workers=20) as executor:
        with AsyncHTMLSession() as session:
            # Set any session parameters here before calling `fetch` 

            # Initialize the event loop        
            loop = asyncio.get_event_loop()

            # Use list comprehension to create a list of
            # tasks to complete. The executor will run the `fetch`
            # function for each url in the urlslist
            tasks = [
                await loop.run_in_executor(
                    executor,
                    fetch,
                    *(session, url) # Allows us to pass in multiple arguments to `fetch`
                )
                for url in urls
            ]

            # Initializes the tasks to run and awaits their results
            for response in await asyncio.gather(*tasks):
                parseWebpage(response)

def main():
    loop = asyncio.get_event_loop()
    future = asyncio.ensure_future(get_data_asynchronous())
    loop.run_until_complete(future)

main()

执行渲染方法后的源代码表示形式不在会话的content属性下,而是在HTML对象中的raw_html下。 在这种情况下,返回的值应该是r.html.raw_html

暂无
暂无

声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.

 
粤ICP备18138465号  © 2020-2024 STACKOOM.COM