动态网页爬取
selenium
下载安装驱动
https://selenium-python.readthedocs.io/index.html
安装位置: python环境变量位置(D:\Anaconda3\Scripts
)
简单使用
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait
browser = webdriver.Chrome()
try:
browser.get('https://www.baidu.com')
input = browser.find_element_by_id('kw')
input.send_keys('Python')
input.send_keys(Keys.ENTER)
wait = WebDriverWait(browser, 10)
wait.until(EC.presence_of_element_located((By.ID, 'content_left')))
print(browser.current_url)
print(browser.get_cookies())
print(browser.page_source)
finally:
browser.close()
声明浏览器对象
from selenium import webdriver
browser = webdriver.Chrome()
browser = webdriver.Firefox()
browser = webdriver.Edge()
browser = webdriver.PhantomJS()
browser = webdriver.Safari()
访问页面
from selenium import webdriver
browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
print(browser.page_source)
browser.close()
元素查找
from selenium import webdriver
browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
input_first = browser.find_element_by_id('q')
input_second = browser.find_element_by_css_selector('#q')
input_third = browser.find_element_by_xpath('//*[@id="q"]')
print(input_first, input_second, input_third)
browser.close()
from selenium import webdriver
from selenium.webdriver.common.by import By
browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
input_first = browser.find_element(By.ID, 'q')
print(input_first)
browser.close()
多个元素查找
from selenium import webdriver
browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
lis = browser.find_elements_by_css_selector('.service-bd li')
print(lis)
browser.close()
from selenium import webdriver
from selenium.webdriver.common.by import By
browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
lis = browser.find_elements(By.CSS_SELECTOR, '.service-bd li')
print(lis)
browser.close()
元素交互
from selenium import webdriver
import time
browser = webdriver.Chrome()
browser.get('https://www.taobao.com')
input = browser.find_element_by_id('q')
input.send_keys('iPhone')
time.sleep(1)
input.clear()
input.send_keys('iPad')
button = browser.find_element_by_class_name('btn-search')
button.click()
执行JavaScript
from selenium import webdriver
browser = webdriver.Chrome()
browser.get('https://www.zhihu.com/explore')
browser.execute_script('window.scrollTo(0, document.body.scrollHeight)')
browser.execute_script('alert("To Bottom")')
获取元素信息
# 获取属性
from selenium import webdriver
from selenium.webdriver import ActionChains
browser = webdriver.Chrome()
url = 'https://www.zhihu.com/explore'
browser.get(url)
logo = browser.find_element_by_id('zh-top-link-logo')
print(logo)
print(logo.get_attribute('class'))
# 获取文本值
from selenium import webdriver
browser = webdriver.Chrome()
url = 'https://www.zhihu.com/explore'
browser.get(url)
input = browser.find_element_by_class_name('zu-top-add-question')
print(input.text)
# 获取ID、位置、标签名、大小
from selenium import webdriver
browser = webdriver.Chrome()
url = 'https://www.zhihu.com/explore'
browser.get(url)
input = browser.find_element_by_class_name('zu-top-add-question')
print(input.id)
print(input.location)
print(input.tag_name)
print(input.size)
Frame
import time
from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException
browser = webdriver.Chrome()
url = 'http://www.runoob.com/try/try.php?filename=jqueryui-api-droppable'
browser.get(url)
browser.switch_to.frame('iframeResult')
source = browser.find_element_by_css_selector('#draggable')
print(source)
try:
logo = browser.find_element_by_class_name('logo')
except NoSuchElementException:
print('NO LOGO')
browser.switch_to.parent_frame()
logo = browser.find_element_by_class_name('logo')
print(logo)
print(logo.text)
等待
隐式等待: 如果 WebDriver没有在 DOM中找到元素,将继续等待,超出设定时间后则抛出找不到元素的异常, 换句话说,当查找元素或元素并没有立即出现的时候,隐式等待将等待一段时间再查找 DOM,默认的时间是0
from selenium import webdriver
browser = webdriver.Chrome()
browser.implicitly_wait(10)
browser.get('https://www.zhihu.com/explore')
input = browser.find_element_by_class_name('zu-top-add-question')
print(input)
显式等待
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
browser = webdriver.Chrome()
browser.get('https://www.taobao.com/')
wait = WebDriverWait(browser, 10)
input = wait.until(EC.presence_of_element_located((By.ID, 'q')))
button = wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, '.btn-search')))
print(input, button)
title_is
标题是某内容
title_contains
标题包含某内容
presence_of_element_located
元素加载出,传入定位元组,如(By.ID, 'p')
visibility_of_element_located
元素可见,传入定位元组
visibility_of
可见,传入元素对象
presence_of_all_elements_located
所有元素加载出
text_to_be_present_in_element
某个元素文本包含某文字
text_to_be_present_in_element_value
某个元素值包含某文字
frame_to_be_available_and_switch_to_it
frame加载并切换
invisibility_of_element_located
元素不可见
element_to_be_clickable
元素可点击
staleness_of
判断一个元素是否仍在DOM,可判断页面是否已经刷新
element_to_be_selected
元素可选择,传元素对象
element_located_to_be_selected
元素可选择,传入定位元组
element_selection_state_to_be
传入元素对象以及状态,相等返回True,否则返回False
element_located_selection_state_to_be
传入定位元组以及状态,相等返回True,否则返回False
alert_is_present
是否出现Alert
前进后退
import time
from selenium import webdriver
browser = webdriver.Chrome()
browser.get('https://www.baidu.com/')
browser.get('https://www.taobao.com/')
browser.get('https://www.python.org/')
browser.back()
time.sleep(1)
browser.forward()
browser.close()
Cookies
from selenium import webdriver
browser = webdriver.Chrome()
browser.get('https://www.zhihu.com/explore')
print(browser.get_cookies())
browser.add_cookie({'name': 'name', 'domain': 'www.zhihu.com', 'value': 'germey'})
print(browser.get_cookies())
browser.delete_all_cookies()
print(browser.get_cookies())
选项卡管理(标签页管理)
import time
from selenium import webdriver
browser = webdriver.Chrome()
browser.get('https://www.baidu.com')
browser.execute_script('window.open()')
print(browser.window_handles)
browser.switch_to_window(browser.window_handles[1])
browser.get('https://www.taobao.com')
time.sleep(1)
browser.switch_to_window(browser.window_handles[0])
browser.get('https://python.org')
异常处理
from selenium import webdriver
from selenium.common.exceptions import TimeoutException, NoSuchElementException
browser = webdriver.Chrome()
try:
browser.get('https://www.baidu.com')
except TimeoutException:
print('Time Out')
try:
browser.find_element_by_id('hello')
except NoSuchElementException:
print('No Element')
finally:
browser.close()
不加载图片
from selenium import wendriver
chrome_options = webdriver.ChromeOptions()
prefs = {"profile.managed_default_content_settings.images": 2}
chrome_options.add_experimental_option("prefs", prefs)
browser = webdriver.Chrome(chrome_options=chrome_options)
class xxxSpider(Spider):
...
def __init__(self):
self.browser = webdriver.Chrome()
super().__init__()
dispatcher.connect(self.spider_closed, signal=signals.spider_closed)
def spider_closed(self):
self.browser.quit()
...
下载中间件
class JSPageMiddleware(object):
def process_request(self, request, spider):
if spider.name == "xxx":
spider.browser.get(request.url)
return HtmlResponse(url=spider.browser.current_url, body=spider.browser.page_source, encoding='utf-8')
不显示浏览器界面
安装pyvirtualdisplay
,webdriver
运行时不会显示
pip install pyvirtualdisplay
from pyvirtualdisplay import Display
from selenium import webdriver
display = Display(visible=0, size=(800, 600))
display.start()
# 现在firefox会运行在一个虚拟的屏幕之中.
# 你看不到它.
browser = webdriver.Chrome()
browser.get('http://www.baidu.com')
print browser.title
browser.quit()
display.stop()