爬虫必知必会（4）_异步协程-selenium_模拟登陆

一、单线程+多任务异步协程(推荐)

协程:对象.可以把协程当做是一个特殊的函数.如果一个函数的定义被async关键字所修饰.该特殊的函数被调用后函数内部的程序语句不会被立即执行,而是会返回一个协程对象.

• 任务对象(task):所谓的任务对象就是对协程对象的进一步封装.在任务对象中可以实现显示协程对象的运行状况. 任务对象最终是需要被注册到事件循环对象中.
• 绑定回调:回调函数是绑定给任务对象,只有当任务对象对应的特殊函数被执行完毕后,回调函数才会被执行
• 事件循环对象:无限循环的对象.也可以把其当成是某一种容器.该容器中需要放置多个任务对象(就是一组待执行的代码块).
• 异步的体现:当事件循环开启后,该对象会安装顺序执行每一个任务对象,当一个任务对象发生了阻塞事件循环是不会等待,而是直接执行下一个任务对象
• await:挂起的操作.交出cpu的使用权
• 多任务的异步协程
• 注意事项:
  • 将多个任务对象存储到一个列表中,然后将该列表注册到事件循环中.在注册的过程中,该列表需要被wait方法进行处理.
  • 在任务对象对应的特殊函数内部的实现中,不可以出现不支持异步模块的代码,否则就会中断整个的 异步效果.并且,在该函数内部每一组阻塞的操作都必须使用await关键字进行修饰.
  • requests模块对应的代码不可以出现在特殊函数内部,因为requests是一个不支持异步的模块

• aiohttp:支持异步操作的网络请求的模块

1. 环境安装:pip install aiohttp
2. 初步的架构:

async def req(url):
　　with aiohttp.ClientSessio() as s:
　　　　with s.get(url) as response:
#response.read():byte
　　　　　　page_text = response.text()
　　　　　　return page_text

• 补充细节:在每一个with前面加上async,在每一步的阻塞操作前加上await

async def req(url):
　　async with aiohttp.ClientSessio() as s:
　　　　async with await s.get(url) as response:
　　　　#response.read():byte
　　　　page_text = await response.text()
　　　　return page_text

二、selenium

• 概念:基于浏览器自动化的一个模块.
• 环境的安装:下载selenium模块
• selenium和爬虫之间的关联是什么?
  • 便捷的获取页面中动态加载的数据
• requests模块进行数据爬取:可见非可得
• selenium:可见即可得
• 实现模拟登录实例化某一款浏览器对象(驱动程序的路径)
  • 基本操作:
  • 谷歌浏览器驱动程序下载地址:http://chromedriver.storage.googleapis.com/index.html
  • 驱动程序和谷歌版本的映射关系表:https://blog.csdn.net/huilan_same/article/details/51896672
• find系列的函数用作于标签定位
• 动作链:一系列的行为动作
• 无头浏览器:无可视化界面的浏览器.
• phantomJS

线程池

from multiprocessing.dummy import Pool
import requests
import time
#同步代码
# start = time.time()
# pool = Pool(3)
#
# urls = ['http://127.0.0.1:5000/bobo','http://127.0.0.1:5000/jay','http://127.0.0.1:5000/tom']
# for url in urls:
#     page_text = requests.get(url).text
#     print(page_text)
# print('总耗时:',time.time()-start)

#异步代码
start = time.time()
pool = Pool(3)
urls = ['http://127.0.0.1:5000/bobo','http://127.0.0.1:5000/jay','http://127.0.0.1:5000/tom']
def get_request(url):
    return requests.get(url).text

response_list = pool.map(get_request,urls)
print(response_list)

#解析
def parse(page_text):
    print(len(page_text))

pool.map(parse,response_list)
print('总耗时:',time.time()-start)

协程对象

# -*- coding: utf-8 -*-
# __author__ = "maple"

from time import sleep
import asyncio

async def get_request(url):
    print('正在请求:',url)
    sleep(2)
    print('请求结束:',url)

c = get_request('www.1.com')
print(c)

任务对象

# -*- coding: utf-8 -*-
# __author__ = "maple"

from time import sleep
import asyncio

#回调函数:
#默认参数:任务对象
def callback(task):
    print('i am callback!!1')
    print(task.result())#result返回的就是任务对象对应的那个特殊函数的返回值

async def get_request(url):
    print('正在请求:',url)
    sleep(2)
    print('请求结束:',url)
    return 'hello bobo'

#创建一个协程对象
c = get_request('www.1.com')
#封装一个任务对象
task = asyncio.ensure_future(c)

#给任务对象绑定回调函数
task.add_done_callback(callback)

#创建一个事件循环对象
loop = asyncio.get_event_loop()
loop.run_until_complete(task)#将任务对象注册到事件循环对象中并且开启了事件循环

多任务异步协程

import asyncio
from time import sleep
import time
start = time.time()
urls = [
    'http://localhost:5000/index',
    'http://localhost:5000/index',
    'http://localhost:5000/index'
]
#在待执行的代码块中不可以出现不支持异步模块的代码
#在该函数内部如果有阻塞操作必须使用await关键字进行修饰
async def get_request(url):
    print('正在请求:',url)
    await asyncio.sleep(2)
    print('请求结束:',url)
    return 'hello bobo'

tasks = [] #放置所有的任务对象
for url in urls:
    c = get_request(url)
    task = asyncio.ensure_future(c)
    tasks.append(task)

loop = asyncio.get_event_loop()
loop.run_until_complete(asyncio.wait(tasks))

print(time.time()-start)

在爬虫中应用多任务异步协程

import asyncio
import requests
import time
start = time.time()
urls = [
    'http://localhost:5000/index',
    'http://localhost:5000/index',
    'http://localhost:5000/index'
]
#无法实现异步的效果:是因为requests模块是一个不支持异步的模块
async def req(url):
    page_text = requests.get(url).text
    return page_text

tasks = []
for url in urls:
    c = req(url)
    task = asyncio.ensure_future(c)
    tasks.append(task)

loop = asyncio.get_event_loop()
loop.run_until_complete(asyncio.wait(tasks))

print(time.time()-start)

aiohttp的使用

import asyncio
import requests
import time
import aiohttp
from lxml import etree
urls = [
    'http://localhost:5000/index',
    'http://localhost:5000/index',
    'http://localhost:5000/index',
    'http://localhost:5000/index',
    'http://localhost:5000/index',
    'http://localhost:5000/index',
]
#无法实现异步的效果:是因为requests模块是一个不支持异步的模块
async def req(url):
    async with aiohttp.ClientSession() as s:
        async with await s.get(url) as response:
            #response.read():byte
            page_text = await response.text()
            return page_text

    #细节:在每一个with前面加上async,在每一步的阻塞操作前加上await

def parse(task):
    page_text = task.result()
    tree = etree.HTML(page_text)
    name = tree.xpath('//p/text()')[0]
    print(name)
if __name__ == '__main__':
    start = time.time()
    tasks = []
    for url in urls:
        c = req(url)
        task = asyncio.ensure_future(c)
        task.add_done_callback(parse)
        tasks.append(task)

    loop = asyncio.get_event_loop()
    loop.run_until_complete(asyncio.wait(tasks))

    print(time.time()-start)

selenium的演示程序

from selenium import webdriver
from time import sleep

# 后面是你的浏览器驱动位置，记得前面加r'','r'是防止字符转义的
driver = webdriver.Chrome(r'C:\Users\oldboy-python\Desktop\爬虫+数据\day04\chromedriver.exe')
# 用get打开百度页面
driver.get("http://www.baidu.com")
# 查找页面的“设置”选项，并进行点击
driver.find_elements_by_link_text('设置')[0].click()
sleep(2)
# # 打开设置后找到“搜索设置”选项，设置为每页显示50条
driver.find_elements_by_link_text('搜索设置')[0].click()
sleep(2)

# 选中每页显示50条
m = driver.find_element_by_id('nr')
sleep(2)
m.find_element_by_xpath('//*[@id="nr"]/option[3]').click()
m.find_element_by_xpath('.//option[3]').click()
sleep(2)

# 点击保存设置
driver.find_elements_by_class_name("prefpanelgo")[0].click()
sleep(2)

# 处理弹出的警告页面   确定accept() 和 取消dismiss()
driver.switch_to_alert().accept()
sleep(2)
# 找到百度的输入框，并输入 美女
driver.find_element_by_id('kw').send_keys('美女')
sleep(2)
# 点击搜索按钮
driver.find_element_by_id('su').click()
sleep(2)
# 在打开的页面中找到“Selenium - 开源中国社区”，并打开这个页面
driver.find_elements_by_link_text('美女_百度图片')[0].click()
sleep(3)

# 关闭浏览器
driver.quit()

selenium的基本操作

from selenium import webdriver
from time import sleep
#实例化一个浏览器对象
bro = webdriver.Chrome(executable_path=r'C:\Users\oldboy-python\Desktop\爬虫+数据\day04\chromedriver.exe')
url = 'https://www.jd.com/'
bro.get(url) #用户发起请求
#定位标签
search_input = bro.find_element_by_id('key')
#对指定标签进行数据交互
search_input.send_keys('macPro')

btn = bro.find_element_by_xpath('//*[@id="search"]/div/div[2]/button')
btn.click()
sleep(2)
#执行js代码
jsCode = 'window.scrollTo(0,document.body.scrollHeight)'
bro.execute_script(jsCode)

sleep(3)
bro.quit()

selenium爬取动态加载的数据

from selenium import webdriver
from lxml import etree
from time import sleep
#实例化一个浏览器对象
page_text_list = []
bro = webdriver.Chrome(executable_path=r'C:\Users\oldboy-python\Desktop\爬虫+数据\day04\chromedriver.exe')
url = 'http://125.35.6.84:81/xk/'
bro.get(url)
sleep(2)
#page_source返回的就是当前浏览器打卡页面对应的页面源码数据
page_text = bro.page_source
page_text_list.append(page_text)

for i in range(2):
    bro.find_element_by_id('pageIto_next').click()
    sleep(2)
    page_text = bro.page_source
    page_text_list.append(page_text)

for page_text in page_text_list:
    tree = etree.HTML(page_text)
    li_list = tree.xpath('//*[@id="gzlist"]/li')
    for li in li_list:
        name = li.xpath('./dl/@title')[0]
        print(name)

sleep(3)
bro.quit()

动作链

from lxml import etree
from time import sleep
from selenium import webdriver
from selenium.webdriver import ActionChains
#实例化一个浏览器对象
page_text_list = []
bro = webdriver.Chrome(executable_path=r'C:\Users\oldboy-python\Desktop\爬虫+数据\day04\chromedriver.exe')
url = 'https://www.runoob.com/try/try.php?filename=jqueryui-api-droppable'
bro.get(url)
#如果定位的标签是存在于iframe对应的子页面中的话,在进行标签定位前一定要执行一个switch_to的操作
bro.switch_to.frame('iframeResult')
div_tag = bro.find_element_by_id('draggable')

#1.实例化动作链对象
action = ActionChains(bro)
action.click_and_hold(div_tag)

for i in range(5):
    #让动作链立即执行
    action.move_by_offset(17,0).perform()
    sleep(0.5)

action.release()

sleep(3)

bro.quit()

无头浏览器

from selenium.webdriver.chrome.options import Options
from time import sleep
from selenium import webdriver

# 创建一个参数对象，用来控制chrome以无界面模式打开
chrome_options = Options()
chrome_options.add_argument('--headless')
chrome_options.add_argument('--disable-gpu')

#实例化一个浏览器对象
bro = webdriver.Chrome(executable_path=r'C:\Users\oldboy-python\Desktop\爬虫+数据\day04\chromedriver.exe',chrome_options=chrome_options)
bro.get('https://www.baidu.com')
sleep(2)
bro.save_screenshot('1.png')
print(bro.page_source)
sleep(2)
bro.quit()

selenium规避风险

# -*- coding: utf-8 -*-
# __author__ = "maple"

from time import sleep
from selenium import webdriver
from selenium.webdriver import ChromeOptions
option = ChromeOptions()
option.add_experimental_option('excludeSwitches', ['enable-automation'])

#实例化一个浏览器对象
bro = webdriver.Chrome(executable_path=r'C:\Users\oldboy-python\Desktop\爬虫+数据\day04\chromedriver.exe',options=option)
bro.get('https://www.taobao.com/')

12306模拟登陆

from selenium import webdriver
from selenium.webdriver import ActionChains
from PIL import Image #用作于图片的裁剪
from ChaoJiYing import Chaojiying_Client
from time import sleep
bro = webdriver.Chrome(executable_path=r'C:\Users\oldboy-python\Desktop\爬虫+数据\day04\chromedriver.exe')
bro.get('https://kyfw.12306.cn/otn/login/init')
sleep(5)
#验证码图片进行捕获(裁剪)
bro.save_screenshot('main.png')
#定位到了验证码图片对应的标签
code_img_ele = bro.find_element_by_xpath('//*[@id="loginForm"]/div/ul[2]/li[4]/div/div/div[3]/img')
location = code_img_ele.location #验证码图片基于当前整张页面的左下角坐标
size = code_img_ele.size #验证码图片的长和宽
#裁剪的矩形区域(左下角和右上角两点的坐标)
rangle = (int(location['x']),int(location['y']),int(location['x']+size['width']),int(location['y']+size['height']))

i = Image.open('main.png')
frame = i.crop(rangle)
frame.save('code.png')

#使用打码平台进行验证码的识别
chaojiying = Chaojiying_Client('bobo328410948', 'bobo328410948', '899370')    #用户中心>>软件ID 生成一个替换 96001
im = open('code.png', 'rb').read()                                                    #本地图片文件路径 来替换 a.jpg 有时WIN系统须要//
result = chaojiying.PostPic(im, 9004)['pic_str']
print(result)#x1,y1|x2,y2|x3,y3  ==> [[x1,y1],[x2,y2],[x3,y3]]
all_list = []#[[x1,y1],[x2,y2],[x3,y3]] 每一个列表元素表示一个点的坐标,坐标对应值的0,0点是验证码图片左下角
if '|' in result:
    list_1 = result.split('|')
    count_1 = len(list_1)
    for i in range(count_1):
        xy_list = []
        x = int(list_1[i].split(',')[0])
        y = int(list_1[i].split(',')[1])
        xy_list.append(x)
        xy_list.append(y)
        all_list.append(xy_list)
else:
    x = int(result.split(',')[0])
    y = int(result.split(',')[1])
    xy_list = []
    xy_list.append(x)
    xy_list.append(y)
    all_list.append(xy_list)

# action = ActionChains(bro)
for l in all_list:
    x = l[0]
    y = l[1]
    ActionChains(bro).move_to_element_with_offset(code_img_ele,x,y).click().perform()
    sleep(1)

sleep(3)
bro.quit()

超级鹰

import requests
from hashlib import md5

class Chaojiying_Client(object):

    def __init__(self, username, password, soft_id):
        self.username = username
        password =  password.encode('utf8')
        self.password = md5(password).hexdigest()
        self.soft_id = soft_id
        self.base_params = {
            'user': self.username,
            'pass2': self.password,
            'softid': self.soft_id,
        }
        self.headers = {
            'Connection': 'Keep-Alive',
            'User-Agent': 'Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0)',
        }

    def PostPic(self, im, codetype):
        """
        im: 图片字节
        codetype: 题目类型 参考 http://www.chaojiying.com/price.html
        """
        params = {
            'codetype': codetype,
        }
        params.update(self.base_params)
        files = {'userfile': ('ccc.jpg', im)}
        r = requests.post('http://upload.chaojiying.net/Upload/Processing.php', data=params, files=files, headers=self.headers)
        return r.json()

    def ReportError(self, im_id):
        """
        im_id:报错题目的图片ID
        """
        params = {
            'id': im_id,
        }
        params.update(self.base_params)
        r = requests.post('http://upload.chaojiying.net/Upload/ReportError.php', data=params, headers=self.headers)
        return r.json()