标签：color 机制 function rgba 时间循环 sha pass 不包含 for
事件循环是asyncio提供的核心运行机制
| column | column |
| asyncio.get_event_loop() | 返回一个事件循环对象,时asyncio.BaseEventLoop的实例 |
| AbstractEventLoop.stop() | 停止运行事件循环 |
| AbstractEventLoop.run_forever() | 一直运行,直到stop() |
| AbstractEventLoop.run_until_complete(future) | 运行直至future对象运行完 |
| AbstractEventLoop.close() | 关闭事件循环对象 |
| AbstractEventLoop.is_running() | 返回事件循环对象是否运行 |
| Abstract Event Loop.close() | 关闭事件循环 |
协程:
协程是用户空间调度完成并发处理的方式
进程,线程由OS完成调度,而协程是线程内完成调度,它不需要更多线程,没有多线程切换带来的开销
协程是非抢占式调度,只有一个协程主动让出控制权,另一个协程才会被调度
协程也不需要使用锁机制,因为是在同一线程中执行
多CPU下,可以使用多进程和协程配合,既能 进程并发又能发挥协程在单线程中的优势
python中协程是基于生成器的
协程的使用:
import asyncio
async def sleep(b):
for i in range(3):
print(‘sleep {}‘.format(i))
await asyncio.sleep(i)
loop=asyncio.get_event_loop()
loop.run_until_complete(sleep(3))
loop.close()
async def 用来定义协程函数,iscoroutinefunction()返回True,协程函数中可以不包含await async关键字,但是不能使用yield关键字
如同生成器函数调用返回生成器对象,协程函数调用也会返回一个对象称为协程对象,
iscoroutine()返回True
iscoroutinefunction()
import asyncio,threading
async def sleep(b):
for v in range(3):
print(‘sleep {}‘.format(v))
await asyncio.sleep(b)
async def show():
for _ in range(3):
print(threading.enumerate())
await asyncio.sleep(2)
print(asyncio.iscoroutinefunction(sleep))
print(asyncio.iscoroutine(sleep))
print(asyncio.iscoroutine(sleep(3)))
loop=asyncio.get_event_loop()
tasks=[sleep(3),show()]
loop.run_until_complete(asyncio.wait(tasks))
loop.close()
TCP Echo Server
import asyncio
async def handle(reader,writer):
while True:
datum=await reader.read(1024)
print(dir(reader))
print(dir(writer))
client=writer.get_extra_info(‘peername‘)
message=‘{} = {}‘.format(client,datum.decode()).encode()
writer.write(message)
await writer.drain()
loop=asyncio.get_event_loop()
crt=asyncio.start_server(handle,‘‘,9999,loop=loop)
server=loop.run_until_complete(crt)
print(server)
try:
loop.run_forever()
except KeyboardInterrupt:
pass
finally:
server.close()
loop.close()
aiohttp
HTTP Server
from aiohttp import web
async def indexhandle(request:web.Request):
return web.Response(text=request.path,status=201)
async def handle(request:web.Request):
print(request.match_info)
print(request.query_string)
return web.Response(text=request.match_info.get(‘id‘,‘000‘),status=200)
app=web.Application()
app.router.add_get(‘/‘,indexhandle)
app.router.add_get(‘/{id}‘,handle)
web.run_app(app,host=‘0.0.0.0‘,port=9988)
HTTP Client
import asyncio
from aiohttp import ClientSession
async def get_html(url:str):
async with ClientSession() as session:
async with session.get(url) as res:
print(res.status)
print(await res.text())
url=‘http://www.baidu.com‘
loop=asyncio.get_event_loop()
loop.run_until_complete(get_html(url))
loop.close()
标签：color 机制 function rgba 时间循环 sha pass 不包含 for
原文地址：https://www.cnblogs.com/dissipate/p/13940798.html
