爬虫入门（十）线程池and协程池爬虫
线程池使用方法介绍
1.实例化线程池对象
from multiprocessing.dummy import Pool
pool = Pool(process=5) #默认大小是cup的个数2.把从发送请求，提取数据，到保存合并成一个函数，交给线程池异步执行，使用方法pool.apply_async(func)
def exetute_requests_item_save(self):
url = self.queue.get()
html_str = self.parse_url(url)
content_list = self.get_content_list(html_str)
self.save_content_list(content_list)
self.total_response_num +=1
pool.apply_async(self.exetute_requests_item_save)3.添加回调函数
通过apply_async的方法能够让函数异步执行，但是只能够执行一次
为了让其能够被反复执行，通过添加回调函数的方式能够让_callback 递归的调用自己,同时需要指定递归退出的条件
def _callback(self,temp):
if self.is_running:
pool.apply_async(self.exetute_requests_item_save,callback=self._callback)
pool.apply_async(self.exetute_requests_item_save,callback=self._callback)4.确定程序结束的条件 程序在获取的响应和url数量相同的时候可以结束
while True: #防止主线程结束
time.sleep(0.0001) #避免cpu空转，浪费资源
if self.total_response_num>=self.total_requests_num:
self.is_running= False
break
self.pool.close() #关闭线程池，防止新的线程开启
# self.pool.join() #等待所有的子线程结束练习
1.使用线程池实现爬虫的具体实现
# coding=utf-8
import requests
from lxml import etree
import time
from queue import Queue
from multiprocessing.dummy import Pool
class QiuBai:
def __init__(self):
self.temp_url = "http://www.qiushibaike.com/8hr/page/{}"
self.headers = {"User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36"}
self.queue = Queue()
self.pool= Pool(5)
self.is_running = True
self.total_request_num = 0
self.total_response_num =0
self.proxies = {"http":"http://58.247.179.94:8060"}
def get_url_list(self):
for i in range(1,14):
self.queue.put(self.temp_url.format(i))
self.total_request_num += 1
def parse_url(self,url):
# response = requests.get(url,headers=self.headers,proxies=self.proxies)
response = requests.get(url,headers=self.headers)
print(response)
return response.content.decode()
def get_content_list(self,html_str):#提取数据
html = etree.HTML(html_str)
div_list = html.xpath("//div[@id='content-left']/div")
content_list = []
for div in div_list:
item = {}
item["user_name"] = div.xpath(".//h2/text()")[0].strip()
item["content"] = [i.strip() for i in div.xpath(".//div[@class='content']/span/text()")]
content_list.append(item)
return content_list
def save_content_list(self,content_list): #保存
for content in content_list:
# print(content)
pass
def _execete_request_content_save(self): #进行一次url地址的请求，提取，保存
url = self.queue.get()
html_str = self.parse_url(url)
#3. 提取数据
content_list = self.get_content_list(html_str)
#4. 保存
self.save_content_list(content_list)
self.total_response_num +=1
def _callback(self,temp):
if self.is_running:
self.pool.apply_async(self._execete_request_content_save,callback=self._callback)
def run(self):#实现做主要逻辑
#1. 准备url列表
self.get_url_list()
for i in range(3): #设置并发数为3
self.pool.apply_async(self._execete_request_content_save,callback=self._callback)
while True:
time.sleep(0.0001)
if self.total_response_num>= self.total_request_num:
self.is_running = False
break
if __name__ == '__main__':
t1 = time.time()
qiubai = QiuBai()
qiubai.run()
print("total cost:",time.time()-t1)2.使用协程池实现爬虫的具体实现
# coding=utf-8
import gevent.monkey
gevent.monkey.patch_all()
from gevent.pool import Pool
import requests
from lxml import etree
import time
from queue import Queue
# from multiprocessing.dummy import Pool
class QiuBai:
def __init__(self):
self.temp_url = "http://www.qiushibaike.com/8hr/page/{}"
self.headers = {"User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36"}
self.queue = Queue()
self.pool= Pool(5)
self.is_running = True
self.total_request_num = 0
self.total_response_num =0
self.proxies = {"http":"http://58.247.179.94:8060"}
def get_url_list(self):
for i in range(1,14):
self.queue.put(self.temp_url.format(i))
self.total_request_num += 1
def parse_url(self,url):
# response = requests.get(url,headers=self.headers,proxies=self.proxies)
response = requests.get(url,headers=self.headers)
print(response)
return response.content.decode()
def get_content_list(self,html_str):#提取数据
html = etree.HTML(html_str)
div_list = html.xpath("//div[@id='content-left']/div")
content_list = []
for div in div_list:
item = {}
item["user_name"] = div.xpath(".//h2/text()")[0].strip()
item["content"] = [i.strip() for i in div.xpath(".//div[@class='content']/span/text()")]
content_list.append(item)
return content_list
def save_content_list(self,content_list): #保存
for content in content_list:
# print(content)
pass
def _execete_request_content_save(self): #进行一次url地址的请求，提取，保存
url = self.queue.get()
html_str = self.parse_url(url)
#3. 提取数据
content_list = self.get_content_list(html_str)
#4. 保存
self.save_content_list(content_list)
self.total_response_num +=1
def _callback(self,temp):
if self.is_running:
self.pool.apply_async(self._execete_request_content_save,callback=self._callback)
def run(self):#实现做主要逻辑
#1. 准备url列表
self.get_url_list()
for i in range(3): #设置并发数为3
self.pool.apply_async(self._execete_request_content_save,callback=self._callback)
while True:
time.sleep(0.0001)
if self.total_response_num>= self.total_request_num:
self.is_running = False
break
if __name__ == '__main__':
t1 = time.time()
qiubai = QiuBai()
qiubai.run()
print("total cost:",time.time()-t1)