解析整个向下滚动的网页的 html 代码 [英] Parse the html code for a whole webpage scrolled down

问题描述

from bs4 import BeautifulSoup
import urllib,sys
reload(sys)
sys.setdefaultencoding("utf-8")
r = urllib.urlopen('https://twitter.com/ndtv').read()
soup = BeautifulSoup(r)

这不会让我把整个网页向下滚动到我想要的末尾，而只会滚动其中的一部分.

This would give me not the whole web page scrolled down the end which I want but only some of it.

from selenium import webdriver
from selenium.common.exceptions import StaleElementReferenceException, TimeoutException
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
import urllib,sys,requests
reload(sys)
sys.setdefaultencoding("utf-8")

class wait_for_more_than_n_elements_to_be_present(object):
    def __init__(self, locator, count):
        self.locator = locator
        self.count = count

    def __call__(self, driver):
        try:
            elements = EC._find_elements(driver, self.locator)
            return len(elements) > self.count
        except StaleElementReferenceException:
            return False

def return_html_code(url):
    driver = webdriver.Firefox()
    driver.maximize_window()
    driver.get(url)
    # initial wait for the tweets to load
    wait = WebDriverWait(driver, 10)
    wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, "li[data-item-id]")))
    # scroll down to the last tweet until there is no more tweets loaded
    while True:
        tweets = driver.find_elements_by_css_selector("li[data-item-id]")
        number_of_tweets = len(tweets)
        print number_of_tweets
        driver.execute_script("arguments[0].scrollIntoView();", tweets[-1])
        try:
            wait.until(wait_for_more_than_n_elements_to_be_present((By.CSS_SELECTOR, "li[data-item-id]"), number_of_tweets))
        except TimeoutException:
            break
    html_full_source=driver.page_source
    driver.close()
    return html_full_source


url='https://twitter.com/thecoolstacks'
#using selenium browser
html_source=return_html_code(url)
soup_selenium = BeautifulSoup(html_source)
print soup_selenium
text_tweet=[]
alltweets_selenium = soup_selenium.find_all(attrs={'data-item-type' : 'tweet'})
for tweet in alltweets_selenium:
    #Text of tweet
    html_tweet= tweet.find_all("p", class_="TweetTextSize TweetTextSize--16px js-tweet-text tweet-text")
    text_tweet.append(''.join(html_tweet[0].findAll(text=True)))    
print text_tweet

预期输出:

import requests from bs4 import BeautifulSoup      url='https://twitter.com/thecoolstacks' 
req = requests.get(url) 
soup = BeautifulSoup(req.content) 
alltweets = soup.find_all(attrs={'data-item-type' : 'tweet'}) 
print alltweets[0]

推荐答案

我仍然坚持使用 Twitter API.

或者，您可以通过以下方式解决 selenium 的问题:

Alternatively, here is how you can approach the problem with selenium:

• 使用显式等待和定义一个自定义预期条件等待要在滚动时加载的推文
• 通过 scrollIntoView()
滚动到最后加载的推文

• use Explicit Waits and define a custom Expected Condition to wait for tweets to load on scroll
• perform the scroll to a last loaded tweet via scrollIntoView()

实施:

from selenium import webdriver
from selenium.common.exceptions import StaleElementReferenceException, TimeoutException
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC


class wait_for_more_than_n_elements_to_be_present(object):
    def __init__(self, locator, count):
        self.locator = locator
        self.count = count

    def __call__(self, driver):
        try:
            elements = EC._find_elements(driver, self.locator)
            return len(elements) > self.count
        except StaleElementReferenceException:
            return False


url = "https://twitter.com/ndtv"
driver = webdriver.Firefox()
driver.maximize_window()
driver.get(url)

# initial wait for the tweets to load
wait = WebDriverWait(driver, 10)
wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, "li[data-item-id]")))

# scroll down to the last tweet until there is no more tweets loaded
while True:
    tweets = driver.find_elements_by_css_selector("li[data-item-id]")
    number_of_tweets = len(tweets)

    driver.execute_script("arguments[0].scrollIntoView();", tweets[-1])

    try:
        wait.until(wait_for_more_than_n_elements_to_be_present((By.CSS_SELECTOR, "li[data-item-id]"), number_of_tweets))
    except TimeoutException:
        break

这将向下滚动到加载该频道中所有现有推文所需的范围.

This would scroll down as much as it is needed to load all of the existing tweets in this channel.

这是提取推文的 HTML 解析片段:

Here is the HTML-parsing snippet, extracting tweets:

page_source = driver.page_source
driver.close()

soup = BeautifulSoup(page_source)
for tweet in soup.select("div.tweet div.content"):
    print tweet.p.text

它打印:

Father's Day Facebook post by arrested cop Suhas Gokhale's son got nearly 10,000 likes http://goo.gl/aPqlxf  pic.twitter.com/JUqmdWNQ3c
#HWL2015 End of third quarter! Breathtaking stuff. India 2-2 Pakistan - http://sports.ndtv.com/hockey/news/244463-hockey-world-league-semifinal-india-vs-pakistan-antwerp …
Why these Kashmiri boys may miss their IIT dream http://goo.gl/9LVKfK  pic.twitter.com/gohX21Gibi
...

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