饮冰三年-人工智能-Python-38 爬虫之并发

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)

# 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)

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)

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)

 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

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
Host: %s

" % (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

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()

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()

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)

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
Host:www.baidu.com

')
#3、等待服务端响应
data = sk.recv(8096) #IO阻塞

#4、关闭连接
sk.close()

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'

', 1)
        self.body = body
        header_list = headers.split(b'
')
        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
Host:%s

"  %(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()