使用Python的web抓取JavaScript页面

我试图开发一个简单的网页刮板。我想提取没有HTML代码的文本。它适用于普通HTML，但不适用于JavaScript代码添加文本的某些页面。

例如，如果一些JavaScript代码添加了一些文本，我不能看到它，因为当我调用:

response = urllib2.urlopen(request)

我得到了原始文本而没有添加的文本(因为JavaScript是在客户端执行的)。

所以，我正在寻找一些解决这个问题的想法。

当前回答

使用PyQt5

from PyQt5.QtWidgets import QApplication
from PyQt5.QtCore import QUrl
from PyQt5.QtWebEngineWidgets import QWebEnginePage
import sys
import bs4 as bs
import urllib.request


class Client(QWebEnginePage):
    def __init__(self,url):
        global app
        self.app = QApplication(sys.argv)
        QWebEnginePage.__init__(self)
        self.html = ""
        self.loadFinished.connect(self.on_load_finished)
        self.load(QUrl(url))
        self.app.exec_()

    def on_load_finished(self):
        self.html = self.toHtml(self.Callable)
        print("Load Finished")

    def Callable(self,data):
        self.html = data
        self.app.quit()

# url = ""
# client_response = Client(url)
# print(client_response.html)

2018-07-14 16:44:29

其他回答

使用PyQt5

from PyQt5.QtWidgets import QApplication
from PyQt5.QtCore import QUrl
from PyQt5.QtWebEngineWidgets import QWebEnginePage
import sys
import bs4 as bs
import urllib.request


class Client(QWebEnginePage):
    def __init__(self,url):
        global app
        self.app = QApplication(sys.argv)
        QWebEnginePage.__init__(self)
        self.html = ""
        self.loadFinished.connect(self.on_load_finished)
        self.load(QUrl(url))
        self.app.exec_()

    def on_load_finished(self):
        self.html = self.toHtml(self.Callable)
        print("Load Finished")

    def Callable(self,data):
        self.html = data
        self.app.quit()

# url = ""
# client_response = Client(url)
# print(client_response.html)

2018-07-14 16:44:29

You'll want to use urllib, requests, beautifulSoup and selenium web driver in your script for different parts of the page, (to name a few). Sometimes you'll get what you need with just one of these modules. Sometimes you'll need two, three, or all of these modules. Sometimes you'll need to switch off the js on your browser. Sometimes you'll need header info in your script. No websites can be scraped the same way and no website can be scraped in the same way forever without having to modify your crawler, usually after a few months. But they can all be scraped! Where there's a will there's a way for sure. If you need scraped data continuously into the future just scrape everything you need and store it in .dat files with pickle. Just keep searching how to try what with these modules and copying and pasting your errors into the Google.

2017-03-28 16:59:07

Pyppeteer

你可以考虑Pyppeteer，它是Chrome/Chromium驱动程序前端的Python移植版本。

下面是一个简单的例子，展示了如何使用pyppeterer动态地访问被注入到页面中的数据:

import asyncio
from pyppeteer import launch

async def main():
    browser = await launch({"headless": True})
    [page] = await browser.pages()

    # normally, you go to a live site...
    #await page.goto("http://www.example.com")
    # but for this example, just set the HTML directly:
    await page.setContent("""
    <body>
    <script>
    // inject content dynamically with JS, not part of the static HTML!
    document.body.innerHTML = `<p>hello world</p>`; 
    </script>
    </body>
    """)
    print(await page.content()) # shows that the `<p>` was inserted

    # evaluate a JS expression in browser context and scrape the data
    expr = "document.querySelector('p').textContent"
    print(await page.evaluate(expr, force_expr=True)) # => hello world

    await browser.close()

asyncio.get_event_loop().run_until_complete(main())

请参阅pyppeterer的参考文档。

2021-03-30 21:32:38

把BeautifulSoup和Selenium混合在一起对我来说效果很好。

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from bs4 import BeautifulSoup as bs

driver = webdriver.Firefox()
driver.get("http://somedomain/url_that_delays_loading")
    try:
        element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.ID, "myDynamicElement"))) #waits 10 seconds until element is located. Can have other wait conditions  such as visibility_of_element_located or text_to_be_present_in_element

        html = driver.page_source
        soup = bs(html, "lxml")
        dynamic_text = soup.find_all("p", {"class":"class_name"}) #or other attributes, optional
    else:
        print("Couldnt locate element")

附注:你可以在这里找到更多的等待条件

2018-05-29 22:29:20

这似乎是一个很好的解决方案，从一个伟大的博客文章

import sys  
from PyQt4.QtGui import *  
from PyQt4.QtCore import *  
from PyQt4.QtWebKit import *  
from lxml import html 

#Take this class for granted.Just use result of rendering.
class Render(QWebPage):  
  def __init__(self, url):  
    self.app = QApplication(sys.argv)  
    QWebPage.__init__(self)  
    self.loadFinished.connect(self._loadFinished)  
    self.mainFrame().load(QUrl(url))  
    self.app.exec_()  

  def _loadFinished(self, result):  
    self.frame = self.mainFrame()  
    self.app.quit()  

url = 'http://pycoders.com/archive/'  
r = Render(url)  
result = r.frame.toHtml()
# This step is important.Converting QString to Ascii for lxml to process

# The following returns an lxml element tree
archive_links = html.fromstring(str(result.toAscii()))
print archive_links

# The following returns an array containing the URLs
raw_links = archive_links.xpath('//div[@class="campaign"]/a/@href')
print raw_links

2016-04-10 20:12:07

使用Python的web抓取JavaScript页面

推荐文章

最新文章

标签