相信爬取大公司的数据时,常常会遇到页面信息动态加载的问题,
如果仅仅使用content = urllib2.urlopen(URL).read(),估计信息是获取不全的,这时候就需要模拟浏览器加载页面的过程,
selenium提供了方便的方法,我也是菜鸟,试了很多种方式,下面提供觉得最靠谱的(已经证明对于爬取新浪微博的topic、twitter under topic完全没问题)。
至于下面的browser变量是什么,看前面的几篇文章。
首先是请求对应的URL:
right_URL = URL.split("from")[0] + "current_page="+str(current_page) + "&since_id="+str(since_id) + "&page="+str(page_index) + "#Pl_Third_App__"+str(Pl_Third_App) print right_URL try: browser.get(right_URL) print "loading more, sleep 3 seconds ... 0" time.sleep(3) # NO need for this sleep, but we add ... browser = selenuim_loading_more(browser, method_index=0) except: print "one exception happen ==> get_tweeter_under_topic 2 ..." pass
然后模拟浏览器,加载更多(推荐使用method_index=0,已经证明比其他好用很多):
def selenuim_loading_more(browser, method_index=0): if method_index==0: browser.implicitly_wait(3) # 为了快速滑动,先设置超时时间为1秒 # while True: for i in range(1, 4): # at most 3 times print "loading more, window.scrollTo bettom for the", i,"time ..." browser.execute_script("window.scrollTo(0,document.body.scrollHeight);") try: # 定位页面底部的换页tab browser.find_element_by_css_selector("div[class='W_pages']") break # 如果没抛出异常就说明找到了底部标志,跳出循环 except NoSuchElementException: pass # 抛出异常说明没找到底部标志,继续向下滑动 browser.implicitly_wait(4) # 将超时时间改回10秒 elif method_index==1: browser.find_element_by_css_selector("div[class='empty_con clearfix']").click() # loading more print "loading more, sleep 4 seconds ... 1" time.sleep(4) browser.find_element_by_css_selector("div[class='empty_con clearfix']").click() # loading more print "loading more, sleep 3 seconds ... 2" time.sleep(2) elif method_index==2: load_more_1 = browser.find_element_by_css_selector("div[class='empty_con clearfix']") # loading more ActionChains(browser).click(load_more_1).perform() print "loading more, sleep 4 seconds ... 1" time.sleep(4) load_more_2 = browser.find_element_by_css_selector("div[class='empty_con clearfix']") # loading more ActionChains(browser).click(load_more_2).perform() print "loading more, sleep 3 seconds ... 2" time.sleep(2) elif method_index==3: print "loading more, sleep 4 seconds ... 1" element = WebDriverWait(browser, 4).until( EC.element_to_be_clickable((By.CSS_SELECTOR, "div[class='empty_con clearfix']")) ) element.click() print "loading more, sleep 2 seconds ... 2" WebDriverWait(browser, 2).until( EC.element_to_be_clickable((By.CSS_SELECTOR, "div[class='empty_con clearfix']")) ).click() return browser
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