饮冰三年-人工智能-Python-38 爬虫之并发

Posted 2020-11-22 逍遥小天狼

一、多线程实现并发

from concurrent.futures import ThreadPoolExecutor
import requests
import time
# 把大象放冰箱一共分几步
#1：找一个冰箱 导入并创建线程池（ThreadPoolExecutor）
#2：大象放进去  pool.submit(task, url)
#3：关门       pool.shutdown(wait=True)
def task(url):
    # 创建get请求
    response = requests.get(url)
    print(url, response)

# 创建一个线程池
pool = ThreadPoolExecutor(7)
url_list = [
    \'http://www.cnblogs.com/wupeiqi\',
    \'http://huaban.com/favorite/beauty/\',
    \'http://www.bing.com\',
    \'http://www.zhihu.com\',
    \'http://www.sina.com\',
    \'http://www.baidu.com\',
    \'http://www.autohome.com.cn\',
]

for url in url_list:
    pool.submit(task, url)

pool.shutdown(wait=True)

线程并发1.0

# 并发--线程

from concurrent.futures import ThreadPoolExecutor
import requests
import time  

#  放好大象你说一声啊
#1：找一个冰箱 导入并创建线程池（ThreadPoolExecutor）
#2：大象放进去  pool.submit(task, url)
#3：关门       pool.shutdown(wait=True)

def task(url):
    response=requests.get(url)
    return response
def done(future,*args,**kwargs):
    response= future.result()
    print(response.status_code,response.content)

pool = ThreadPoolExecutor(7)
url_list = [
    \'http://www.cnblogs.com/wupeiqi\',
    \'http://huaban.com/favorite/beauty/\',
    \'http://www.bing.com\',
    \'http://www.zhihu.com\',
    \'http://www.sina.com\',
    \'http://www.baidu.com\',
    \'http://www.autohome.com.cn\',
]
for url in url_list:
    v = pool.submit(task,url)
    v.add_done_callback(done)

pool.shutdown(wait=True)

线程并发2.0

二、多进程并发和多线程并发代码类似，只是引入的包不同

from concurrent.futures import ProcessPoolExecutor
import requests
import time

def task(url):
    response = requests.get(url)
    print(url,response)
    # 写正则表达式


if __name__ == "__main__":
    pool = ProcessPoolExecutor(7)
    url_list = [
        \'http://www.cnblogs.com/wupeiqi\',
        \'http://huaban.com/favorite/beauty/\',
        \'http://www.bing.com\',
        \'http://www.zhihu.com\',
        \'http://www.sina.com\',
        \'http://www.baidu.com\',
        \'http://www.autohome.com.cn\',
    ]
    for url in url_list:
        pool.submit(task, url)

    pool.shutdown(wait=True)

进程并发1.0

from concurrent.futures import ProcessPoolExecutor
import requests
import time

def task(url):
    response = requests.get(url)
    return response

def done(future,*args,**kwargs):
    response = future.result()
    print(response.status_code,response.content)

if __name__ == "__main__":
    pool = ProcessPoolExecutor(7)
    url_list = [
        \'http://www.cnblogs.com/wupeiqi\',
        \'http://huaban.com/favorite/beauty/\',
        \'http://www.bing.com\',
        \'http://www.zhihu.com\',
        \'http://www.sina.com\',
        \'http://www.baidu.com\',
        \'http://www.autohome.com.cn\',
    ]
    for url in url_list:
        v=pool.submit(task, url)
        v.add_done_callback(done)

    pool.shutdown(wait=True)

进程并发2.0

 三、协程 + 异步IO

需要安装一下包 pip install aiohttp、requests、greenlet、gevent、grequests

import asyncio
@asyncio.coroutine
def task():
    print(\'before...task...\')
    yield from asyncio.sleep(5) #仅支持TCP获取结果，大象内部携程并发
    print(\'end...task...\')

tasks=[task(),task()]

loop = asyncio.get_event_loop()     #打开冰箱门
loop.run_until_complete(asyncio.gather(*tasks)) #大象放进去
loop.close()  #关门

示例一、asyncio初识

import asyncio
@asyncio.coroutine
def task(host,url=\'/\'):
    print(\'before...task...\',host,url)
    reader,writer= yield from asyncio.open_connection(host,80) #仅支持TCP获取结果，大象内部携程并发
    request_header_content = "GET %s HTTP/1.0\\r\\nHost: %s\\r\\n\\r\\n" % (url, host,)
    request_header_content = bytes(request_header_content, encoding=\'utf-8\')

    writer.write(request_header_content)
    yield from writer.drain()
    text = yield from reader.read()
    print(\'end\', host, url, text)
    writer.close()

tasks=[task(\'www.cnblogs.com\', \'/Yk2012/\'),
       task(\'www.baidu.com\')]

loop = asyncio.get_event_loop()     #打开冰箱门
loop.run_until_complete(asyncio.gather(*tasks)) #大象放进去
loop.close()  #关门

示例二、自己封装Http数据包

import aiohttp
import asyncio


@asyncio.coroutine
def fetch_async(url):
    print(url)
    response = yield from aiohttp.request(\'GET\', url)
    print(url, response)
    response.close()


tasks = [fetch_async(\'http://www.baidu.com/\'), fetch_async(\'http://www.chouti.com/\')]

event_loop = asyncio.get_event_loop()
results = event_loop.run_until_complete(asyncio.gather(*tasks))
event_loop.close()

示例三、使用aiohttp

import asyncio
import requests

@asyncio.coroutine
def task(func, *args):
    print(func,args)
    loop = asyncio.get_event_loop()
    future = loop.run_in_executor(None, func, *args) # requests.get(\'http://www.cnblogs.com/wupeiqi/\')
    response = yield from future
    print(response.url, response.content)


tasks = [
    task(requests.get, \'http://www.cnblogs.com/wupeiqi/\'),
    task(requests.get, \'http://dig.chouti.com/pic/show?nid=4073644713430508&lid=10273091\')
]

loop = asyncio.get_event_loop()
results = loop.run_until_complete(asyncio.gather(*tasks))
loop.close()

示例四、aiohttp+request

 

import grequests

import grequests


request_list = [
    grequests.get(\'https://baidu.com/\'),
]


# ##### 执行并获取响应列表 #####
response_list = grequests.map(request_list,size=5)
print(response_list)

示例五、grequests

 

四、自定义异步IO

import socket
import select

sk = socket.socket()
#1、连接
sk.connect({\'www.baidu.com\',80,}) #IO阻塞
#2、发送消息
sk.send(b\'GET / HTTP/1.0\\r\\nHost:www.baidu.com\\r\\n\\r\\n\')
#3、等待服务端响应
data = sk.recv(8096) #IO阻塞

#4、关闭连接
sk.close()

http请求本质

import socket
import select
class HttpResponse:
    def __init__(self,recv_data):
        self.recv_data = recv_data
        self.header_dict = {}
        self.body = None

        self.initialize()
    def initialize(self):
        headers, body = self.recv_data.split(b\'\\r\\n\\r\\n\', 1)
        self.body = body
        header_list = headers.split(b\'\\r\\n\')
        for h in header_list:
            h_str = str(h,encoding=\'utf-8\')
            v = h_str.split(\':\',1)
            if len(v) == 2:
                self.header_dict[v[0]] = v[1]
class HttpRequest:
    def __init__(self,socket,host,callback):
        self.socket = socket
        self.host=host
        self.callback = callback #会掉函数
    def fileno(self):
        \'\'\'有了fileno方法，那么这个对象也可以select了\'\'\'
        return self.socket.fileno()
class AsyncRequest:
    def __init__(self):
        self.conn = []   # 用于检测消息是否接收完成
        self.connection = [] # 用于检测是否已经连接成功
    def add_request(self,host,callback):
        try:
            sk = socket.socket() #创建sk，
            sk.setblocking(0) #关闭阻塞
            sk.connect((host,80,)) #sk连接
        except BlockingIOError as e:
            pass
        # 创建一个Request对象（sk, host）
        request = HttpRequest(sk,host,callback)
        # 把这个对象放到两个属性中
        self.conn.append(request)
        self.connection.append(request)
    def run(self):
        while True:
            rlist,wlist,elist = select.select(self.conn,self.connection,self.conn,0.05)
            for w in wlist:
                print(w.host, \'连接成功...\')
                 # 只要能循环到，表示socket和服务器端已经连接成功 发送消息
                tpl = "GET / HTTP/1.0\\r\\nHost:%s\\r\\n\\r\\n"  %(w.host,)
                w.socket.send(bytes(tpl,encoding=\'utf-8\'))
                self.connection.remove(w) #链接成功后，从connection中删除
            for r in rlist:
                recv_data = bytes()
                #为了防止数据丢失，需要while True一直接收
                while True:
                    try :
                        chunck = r.socket.recv(8096)
                        recv_data += chunck    # 接收消息
                    except Exception as e:
                        break
                # 接收完消息，赋给HttpResponse
                resonse = HttpResponse(recv_data)
                r.callback(resonse) #接收完响应，调用回调函数
                r.socket.close() #r接收完响应，关闭请求。
                self.conn.remove(r) #接收完响应，从conn中移除

            # 数据接收完成后，conn为空。结束循环
            if len(self.conn) == 0:
                break

def f1(response):
    print(\'保存到文件\',response.header_dict)

def f2(response):
    print(\'保存到数据库\', response.header_dict)

url_list = [
    {\'host\':\'www.baidu.com\',\'callback\': f1},
    {\'host\':\'cn.bing.com\',\'callback\': f2},
    {\'host\':\'www.cnblogs.com\',\'callback\': f2},
]

req = AsyncRequest()
for item in url_list:
    req.add_request(item[\'host\'],item[\'callback\'])

req.run()

自定义异步IO