- asynico
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 # learn:https://pythonav.com/wiki/detail/6/91/ 5 6 # Python3.8之后 @asyncio.coroutine 装饰器就会被移除,推荐使用async & awit 关键字实现协程代码。 7 8 import asyncio 9 async def func1(): 10 print(1) 11 await asyncio.sleep(2) 12 print(2) 13 async def func2(): 14 print(3) 15 await asyncio.sleep(2) 16 print(4) 17 tasks = [ 18 asyncio.ensure_future(func1()), 19 asyncio.ensure_future(func2()) 20 ] 21 loop = asyncio.get_event_loop() 22 loop.run_until_complete(asyncio.wait(tasks)) 23 24 25 """ 26 import asyncio 27 @asyncio.coroutine 28 def func1(): 29 print(1) 30 yield from asyncio.sleep(2) # 遇到IO耗时操作,自动化切换到tasks中的其他任务 31 print(2) 32 @asyncio.coroutine 33 def func2(): 34 print(3) 35 yield from asyncio.sleep(2) # 遇到IO耗时操作,自动化切换到tasks中的其他任务 36 print(4) 37 tasks = [ 38 asyncio.ensure_future( func1() ), 39 asyncio.ensure_future( func2() ) 40 ] 41 loop = asyncio.get_event_loop() 42 loop.run_until_complete(asyncio.wait(tasks)) 43 """
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 import time 5 from functools import wraps 6 def time_cost(func): 7 @wraps(func) 8 def inner(*args, **kwargs): 9 start_time = time.time() 10 ret = func(*args, **kwargs) 11 end_time = time.time() 12 print('总用时:%s 秒' % (end_time - start_time)) 13 14 return inner 15 16 """ 17 18 # 方式一:同步编程实现 19 import requests 20 21 22 def download_image(url): 23 print("开始下载:", url) 24 # 发送网络请求,下载图片 25 response = requests.get(url) 26 print("下载完成") 27 # 图片保存到本地文件 28 file_name = url.rsplit('_')[-1] 29 with open('img/' + file_name, mode='wb') as file_object: 30 file_object.write(response.content) 31 32 33 @time_cost 34 def start_downloads(url_list): 35 for item in url_list: 36 download_image(item) 37 38 39 if __name__ == '__main__': 40 url_lists = [ 41 'https://www3.autoimg.cn/newsdfs/g26/M02/35/A9/120x90_0_autohomecar__ChsEe12AXQ6AOOH_AAFocMs8nzU621.jpg', 42 'https://www2.autoimg.cn/newsdfs/g30/M01/3C/E2/120x90_0_autohomecar__ChcCSV2BBICAUntfAADjJFd6800429.jpg', 43 'https://www3.autoimg.cn/newsdfs/g26/M0B/3C/65/120x90_0_autohomecar__ChcCP12BFCmAIO83AAGq7vK0sGY193.jpg' 44 ] 45 start_downloads(url_list=url_lists) 46 47 """ 48 49 # 方式二:基于协程的异步编程实现 (请提前安装:pip3 install aiohttp) 50 import aiohttp 51 import asyncio 52 async def fetch(session, url): 53 print("发送请求:", url) 54 async with session.get(url, verify_ssl=False) as response: 55 content = await response.content.read() 56 file_name = url.rsplit('_')[-1] 57 with open('img/' + file_name, mode='wb') as file_object: 58 file_object.write(content) 59 60 async def main(): 61 async with aiohttp.ClientSession() as session: 62 url_list = [ 63 'https://www3.autoimg.cn/newsdfs/g26/M02/35/A9/120x90_0_autohomecar__ChsEe12AXQ6AOOH_AAFocMs8nzU621.jpg', 64 'https://www2.autoimg.cn/newsdfs/g30/M01/3C/E2/120x90_0_autohomecar__ChcCSV2BBICAUntfAADjJFd6800429.jpg', 65 'https://www3.autoimg.cn/newsdfs/g26/M0B/3C/65/120x90_0_autohomecar__ChcCP12BFCmAIO83AAGq7vK0sGY193.jpg' 66 ] 67 tasks = [asyncio.create_task(fetch(session, url)) for url in url_list] 68 await asyncio.wait(tasks) 69 if __name__ == '__main__': 70 @time_cost 71 def run(): 72 asyncio.run(main()) 73 run()
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 import asyncio 4 async def func(): 5 print("协程内部代码") 6 # 调用协程函数,返回一个协程对象。 7 result = func() 8 # 方式一 9 # loop = asyncio.get_event_loop() # 创建一个事件循环 10 # loop.run_until_complete(result) # 将协程当做任务提交到事件循环的任务列表中,协程执行完成之后终止。 11 # 方式二 12 # 本质上方式一是一样的,内部先 创建事件循环 然后执行 run_until_complete,一个简便的写法。 13 # asyncio.run 函数在 Python 3.7 中加入 asyncio 模块, 14 asyncio.run(result)
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 # await 5 # await是一个只能在协程函数中使用的关键字,用于遇到IO操作时挂起 当前协程(任务),当前协程(任务)挂起过程中 事件循环可以去执行其他的协程(任务),当前协程IO处理完成时,可以再次切换回来执行await之后的代码。代码如下: 6 7 # # 示例1: 8 9 # import asyncio 10 # async def func(): 11 # print("执行协程函数内部代码") 12 # # 遇到IO操作挂起当前协程(任务),等IO操作完成之后再继续往下执行。 13 # # 当前协程挂起时,事件循环可以去执行其他协程(任务)。 14 # response = await asyncio.sleep(2) 15 # print("IO请求结束,结果为:", response) 16 # result = func() 17 # asyncio.run(result) 18 19 # 示例2: 20 # import asyncio 21 # async def others(): 22 # print("start") 23 # await asyncio.sleep(2) 24 # print('end') 25 # return '返回值' 26 # async def func(): 27 # print("执行协程函数内部代码") 28 # # 遇到IO操作挂起当前协程(任务),等IO操作完成之后再继续往下执行。当前协程挂起时,事件循环可以去执行其他协程(任务)。 29 # response = await others() 30 # print("IO请求结束,结果为:", response) 31 # asyncio.run( func() ) 32 33 # 示例3: 34 import asyncio 35 async def others(): 36 print("start") 37 await asyncio.sleep(2) 38 print('end') 39 return '返回值' 40 async def func(): 41 print("执行协程函数内部代码") 42 # 遇到IO操作挂起当前协程(任务),等IO操作完成之后再继续往下执行。当前协程挂起时,事件循环可以去执行其他协程(任务)。 43 response1 = await others() 44 print("IO请求结束,结果为:", response1) 45 response2 = await others() 46 print("IO请求结束,结果为:", response2) 47 asyncio.run( func() )
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 import asyncio 5 async def func(): 6 print(1) 7 await asyncio.sleep(2) 8 print(2) 9 return "返回值" 10 async def main(): 11 print("main开始") 12 # 创建协程,将协程封装到Task对象中并添加到事件循环的任务列表中,等待事件循环去执行(默认是就绪状态)。 13 # 在调用 14 task_list = [ 15 asyncio.create_task(func()), 16 asyncio.create_task(func()) 17 ] 18 print("main结束") 19 # 当执行某协程遇到IO操作时,会自动化切换执行其他任务。 20 # 此处的await是等待所有协程执行完毕,并将所有协程的返回值保存到done 21 # 如果设置了timeout值,则意味着此处最多等待的秒,完成的协程返回值写入到done中,未完成则写到pending中。 22 done, pending = await asyncio.wait(task_list, timeout=None) 23 print(done, pending) 24 25 asyncio.run(main())
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 import time 5 from concurrent.futures import Future 6 from concurrent.futures.thread import ThreadPoolExecutor 7 from concurrent.futures.process import ProcessPoolExecutor 8 def func(value): 9 time.sleep(1) 10 print(value) 11 pool = ThreadPoolExecutor(max_workers=5) # 创建线程池 12 # 或 pool = ProcessPoolExecutor(max_workers=5) 3 创建进程池 13 for i in range(10): 14 fut = pool.submit(func, i) 15 print(fut)
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 5 # 此种对象通过定义 __aenter__() 和 __aexit__() 方法来对 async with 语句中的环境进行控制。由 PEP 492 引入。 6 import asyncio 7 class AsyncContextManager: 8 def __init__(self): 9 self.conn = None 10 async def do_something(self): 11 # 异步操作数据库 12 return 666 13 async def __aenter__(self): 14 # 异步链接数据库 15 self.conn = await asyncio.sleep(1) 16 return self 17 async def __aexit__(self, exc_type, exc, tb): 18 # 异步关闭数据库链接 19 await asyncio.sleep(1) 20 async def func(): 21 async with AsyncContextManager() as f: 22 result = await f.do_something() 23 print(result) 24 asyncio.run(func())
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 # pip3 install uvloop 5 # 在项目中想要使用uvloop替换asyncio的事件循环也非常简单,只要在代码中这么做就行。 6 7 import asyncio 8 import uvloop 9 asyncio.set_event_loop_policy(uvloop.EventLoopPolicy()) 10 # 编写asyncio的代码,与之前写的代码一致。 11 # 内部的事件循环自动化会变为uvloop 12 asyncio.run(...)
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 # 安装Python异步操作redis模块 5 # pip3 install aioredis 6 7 # 示例1:异步操作redis。 8 9 #!/usr/bin/env python 10 # -*- coding:utf-8 -*- 11 12 # import asyncio 13 # import aioredis 14 # async def execute(address, password): 15 # print("开始执行", address) 16 # # 网络IO操作:创建redis连接 17 # redis = await aioredis.create_redis(address, password=password) 18 # # 网络IO操作:在redis中设置哈希值car,内部在设三个键值对,即: redis = { car:{key1:1,key2:2,key3:3}} 19 # await redis.hmset_dict('car', key1=1, key2=2, key3=3) 20 # # 网络IO操作:去redis中获取值 21 # result = await redis.hgetall('car', encoding='utf-8') 22 # print(result) 23 # redis.close() 24 # # 网络IO操作:关闭redis连接 25 # await redis.wait_closed() 26 # print("结束", address) 27 # asyncio.run(execute('redis://47.93.4.198:6379', "root!2345")) 28 29 30 # 示例2:连接多个redis做操作(遇到IO会切换其他任务,提供了性能)。 31 32 import asyncio 33 import aioredis 34 async def execute(address, password): 35 print("开始执行", address) 36 # 网络IO操作:先去连接 47.93.4.197:6379,遇到IO则自动切换任务,去连接47.93.4.198:6379 37 redis = await aioredis.create_redis_pool(address, password=password) 38 # 网络IO操作:遇到IO会自动切换任务 39 await redis.hmset_dict('car', key1=1, key2=2, key3=3) 40 # 网络IO操作:遇到IO会自动切换任务 41 result = await redis.hgetall('car', encoding='utf-8') 42 print(result) 43 redis.close() 44 # 网络IO操作:遇到IO会自动切换任务 45 await redis.wait_closed() 46 print("结束", address) 47 48 task_list = [ 49 execute('redis://47.93.4.197:6379', "root!2345"), 50 execute('redis://47.93.4.198:6379', "root!2345") 51 ] 52 asyncio.run(asyncio.wait(task_list))
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 # 当通过python去操作MySQL时,连接、执行SQL、关闭都涉及网络IO请求,使用asycio异步的方式可以在IO等待时去做一些其他任务,从而提升性能。 5 # 6 # 安装Python异步操作redis模块 7 # pip3 install aiomysql 8 9 # # 示例1: 10 # 11 # import asyncio 12 # import aiomysql 13 # async def execute(): 14 # # 网络IO操作:连接MySQL 15 # conn = await aiomysql.connect(host='127.0.0.1', port=3306, user='root', password='123', db='mysql', ) 16 # # 网络IO操作:创建CURSOR 17 # cur = await conn.cursor() 18 # # 网络IO操作:执行SQL 19 # await cur.execute("SELECT Host,User FROM user") 20 # # 网络IO操作:获取SQL结果 21 # result = await cur.fetchall() 22 # print(result) 23 # # 网络IO操作:关闭链接 24 # await cur.close() 25 # conn.close() 26 # asyncio.run(execute()) 27 28 # 示例2: 29 30 #!/usr/bin/env python 31 # -*- coding:utf-8 -*- 32 import asyncio 33 import aiomysql 34 async def execute(host, password): 35 print("开始", host) 36 # 网络IO操作:先去连接 47.93.40.197,遇到IO则自动切换任务,去连接47.93.40.198:6379 37 conn = await aiomysql.connect(host=host, port=3306, user='root', password=password, db='mysql') 38 # 网络IO操作:遇到IO会自动切换任务 39 cur = await conn.cursor() 40 # 网络IO操作:遇到IO会自动切换任务 41 await cur.execute("SELECT Host,User FROM user") 42 # 网络IO操作:遇到IO会自动切换任务 43 result = await cur.fetchall() 44 print(result) 45 # 网络IO操作:遇到IO会自动切换任务 46 await cur.close() 47 conn.close() 48 print("结束", host) 49 task_list = [ 50 execute('47.93.40.197', "root!2345"), 51 execute('47.93.40.197', "root!2345") 52 ] 53 asyncio.run(asyncio.wait(task_list))
1 #!UsersLocalProgramsPython37 2 # -*- coding: utf-8 -*- 3 4 # 爬虫 5 # 在编写爬虫应用时,需要通过网络IO去请求目标数据,这种情况适合使用异步编程来提升性能,接下来我们使用支持异步编程的aiohttp模块来实现。 6 # 安装aiohttp模块 7 # pip3 install aiohttp 8 # 示例: 9 10 import aiohttp 11 import asyncio 12 async def fetch(session, url): 13 print("发送请求:", url) 14 async with session.get(url, verify_ssl=False) as response: 15 text = await response.text() 16 print("得到结果:", url, len(text)) 17 async def main(): 18 async with aiohttp.ClientSession() as session: 19 url_list = [ 20 'https://python.org', 21 'https://www.baidu.com', 22 'https://www.pythonav.com' 23 ] 24 tasks = [asyncio.create_task(fetch(session, url)) for url in url_list] 25 await asyncio.wait(tasks) 26 if __name__ == '__main__': 27 asyncio.run(main())
- IO 模型
阻塞io
1 from socket import * 2 3 client=socket(AF_INET,SOCK_STREAM) 4 client.connect(('127.0.0.1',8080)) 5 6 7 while True: 8 msg=input('>>: ').strip() 9 if not msg:continue 10 client.send(msg.encode('utf-8')) 11 data=client.recv(1024) 12 print(data.decode('utf-8')) 13 14 client.close()
1 from socket import * 2 from threading import Thread 3 4 def communicate(conn): 5 while True: 6 try: 7 data = conn.recv(1024) 8 if not data: break 9 conn.send(data.upper()) 10 except ConnectionResetError: 11 break 12 13 conn.close() 14 15 16 17 server = socket(AF_INET, SOCK_STREAM) 18 server.bind(('127.0.0.1',8080)) 19 server.listen(5) 20 21 while True: 22 print('starting...') 23 conn, addr = server.accept() 24 print(addr) 25 26 t=Thread(target=communicate,args=(conn,)) 27 t.start() 28 29 server.close()
非阻塞io
1 from socket import * 2 3 client=socket(AF_INET,SOCK_STREAM) 4 client.connect(('127.0.0.1',8083)) 5 6 7 while True: 8 msg=input('>>: ').strip() 9 if not msg:continue 10 client.send(msg.encode('utf-8')) 11 data=client.recv(1024) 12 print(data.decode('utf-8')) 13 14 client.close()
1 from socket import * 2 3 server = socket(AF_INET, SOCK_STREAM) 4 server.bind(('127.0.0.1',8083)) 5 server.listen(5) 6 server.setblocking(False) 7 print('starting...') 8 9 10 rlist=[] 11 wlist=[] 12 while True: 13 14 try: 15 conn, addr = server.accept() 16 rlist.append(conn) 17 print(rlist) 18 except BlockingIOError: 19 # print('干其他的活') 20 21 #收消息 22 del_rlist = [] 23 for conn in rlist: 24 try: 25 data=conn.recv(1024) 26 if not data: 27 del_rlist.append(conn) 28 continue 29 wlist.append((conn,data.upper())) 30 except BlockingIOError: 31 continue 32 except Exception: 33 conn.close() 34 del_rlist.append(conn) 35 36 #发消息 37 del_wlist=[] 38 for item in wlist: 39 try: 40 conn=item[0] 41 data=item[1] 42 conn.send(data) 43 del_wlist.append(item) 44 except BlockingIOError: 45 pass 46 47 for item in del_wlist: 48 wlist.remove(item) 49 50 for conn in del_rlist: 51 rlist.remove(conn) 52 53 54 server.close()
多路复用IO (select的使用)
1 from socket import * 2 3 client=socket(AF_INET,SOCK_STREAM) 4 client.connect(('127.0.0.1',8083)) 5 6 7 while True: 8 msg=input('>>: ').strip() 9 if not msg:continue 10 client.send(msg.encode('utf-8')) 11 data=client.recv(1024) 12 print(data.decode('utf-8')) 13 14 client.close()
1 from socket import * 2 import select 3 4 server = socket(AF_INET, SOCK_STREAM) 5 server.bind(('127.0.0.1',8083)) 6 server.listen(5) 7 server.setblocking(False) 8 print('starting...') 9 10 rlist=[server,] 11 wlist=[] 12 wdata={} 13 14 while True: 15 rl,wl,xl=select.select(rlist,wlist,[],0.5) 16 print('rl',rl) 17 print('wl',wl) 18 19 for sock in rl: 20 if sock == server: 21 conn,addr=sock.accept() 22 rlist.append(conn) 23 else: 24 try: 25 data=sock.recv(1024) 26 if not data: 27 sock.close() 28 rlist.remove(sock) 29 continue 30 wlist.append(sock) 31 wdata[sock]=data.upper() 32 except Exception: 33 sock.close() 34 rlist.remove(sock) 35 36 for sock in wl: 37 data=wdata[sock] 38 sock.send(data) 39 wlist.remove(sock) 40 wdata.pop(sock) 41 42 server.close()