Selenium 模拟浏览器动态加载页面的实现方法
时间：2021-05-14 10:36:33|栏目：Python代码|点击： 次
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
