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aio |

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* 学习资料

http://www.jianshu.com/p/b5e347b3a17c

* 事件驱动形IO

* 3.5版本以前

1,在生成器上标识注解 @asyncio.coroutine

然后在coroutine内部用yield from调用另一个 coroutine 实现异步操作

2,创建 event_loop 对象(asyncio.get_event_loop())

3,执行 event_loop 对象的 run_until_complete()函数,把生成器实例作为参数传递进去

* 该函数参数也可以是 asyncio.wait(tast_arr) 函数返回值

* 表示一次性执行多个生成器

* demo :

tasks = [hello(), hello()]

loop.run_until_complete(asyncio.wait(tasks))

4,关闭 event_loop 对象 (close())

* 3.5 版本以后

* 用asyncio提供的 @asyncio.coroutine 可以把一个generator标记为coroutine类型,然后在coroutine内部用yield from调用另一个 coroutine 实现异步操作

* 为了简化并更好地标识异步IO，从Python 3.5开始引入了新的语法async和await,可以让coroutine的代码更简洁易读

* 请注意,async和await是针对coroutine的新语法,要使用新的语法,只需要做两步简单的替换

* 步骤

1,生成器不使用 @asyncio.coroutine 注解标识,而使用 async 关键字标识

2,不使用 yield from 语句,而使用 await 关键字

* demo

import asyncio

async def demo(name):

print('[%s]1'%(name))

r = await asyncio.sleep(2)

print('[%s]2'%(name))

loop = asyncio.get_event_loop()

loop.run_until_complete(asyncio.wait([demo('Kevin'),demo('Litch')]))

* event_loop api

create_task()

run_until_complete()

run_forever()

create_server()

close()

stop()

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aio-入门 |

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import asyncio

@asyncio.coroutine

def hello():

print("Hello world!")

# 异步调用asyncio.sleep(1):

r = yield from asyncio.sleep(1)

print("Hello again!")

# 获取EventLoop:

loop = asyncio.get_event_loop()

# 执行coroutine

loop.run_until_complete(hello())

loop.close()

'''

Hello world!

Hello again!

'''

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aio-进阶 |

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import threading

import asyncio

@asyncio.coroutine

def hello():

print('Hello world! (%s)' % threading.currentThread())

yield from asyncio.sleep(1)

print('Hello again! (%s)' % threading.currentThread())

loop = asyncio.get_event_loop()

tasks = [hello(), hello()]

loop.run_until_complete(asyncio.wait(tasks))

loop.close()

'''

Hello world! (<_MainThread(MainThread, started 6956)>)

Hello world! (<_MainThread(MainThread, started 6956)>)

Hello again! (<_MainThread(MainThread, started 6956)>)

Hello again! (<_MainThread(MainThread, started 6956)>)

'''

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aio-结果回调 |

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import asyncio

async def demo(var):

asyncio.sleep(1)

return var * var

# 创建 loop

loop = asyncio.get_event_loop()

# 创建 task

task = asyncio.ensure_future(demo(5))

# task添加监听,在回调函数中调用形参的 result() 获取结果信息

# task和回调里的x对象,实际上是同一个对象

task.add_done_callback(lambda x : print('result:%s'%(x.result())))

# 执行任务

loop.run_until_complete(asyncio.wait([task]))

loop.close()

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aio-server |

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import asyncio

class SimpleProtocol(asyncio.Protocol):

# 新的连接

def connection_made(self, transport):

self.transport = transport

# 收到新的数据

def data_received(self, data):

# 把收到的数据响应给客户端

self.transport.write(data)

# 连接断开

def connection_lost(self, exception):

#server.close()

pass

# 创建 event_loop

loop = asyncio.get_event_loop()

# 创建服务器实例

server = loop.run_until_complete(loop.create_server(SimpleProtocol, 'localhost', 1024))

# 运行

loop.run_until_complete(server.wait_closed())

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aio-实战 |

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# 旧版实现

import asyncio

@asyncio.coroutine

def wget(host):

print('wget %s...' % host)

connect = asyncio.open_connection(host, 80)

reader, writer = yield from connect

header = 'GET / HTTP/1.0\r\nHost: %s\r\n\r\n' % host

writer.write(header.encode('utf-8'))

yield from writer.drain()

while True:

line = yield from reader.readline()

if line == b'\r\n':

break

print('%s header > %s' % (host, line.decode('utf-8').rstrip()))

# Ignore the body, close the socket

writer.close()

loop = asyncio.get_event_loop()

tasks = [wget(host) for host in ['www.sina.com.cn', 'www.sohu.com', 'www.163.com']]

loop.run_until_complete(asyncio.wait(tasks))

loop.close()

# 新版实现

import asyncio

async def demo(target):

reader, writer = await asyncio.open_connection(*target)

header = 'GET / HTTP/1.0\r\nHost: %s\r\n\r\n'%(target[1])

writer.write(bytes(header,'UTF_8'))

await writer.drain()

while True:

line = await reader.readline()

if line == b'\r\n':

break

print('%s header > %s' %(target[1], line.decode('utf-8').rstrip()))

writer.close()

loop = asyncio.get_event_loop()

loop.run_until_complete(asyncio.wait([demo(('www.qq.com',80)),demo(('www.javaweb.io',80))]))

loop.close()

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aio-asyncio |

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wait()

gather()

* 跟 wait() 一样,不过它会返回一个[],里面的每个元素是每个协程执行完毕后的结果

ensure_future()

get_event_loop()

as_completed()

open_connection(ip, port)

* 打开一个异步IO连接

* 返回 (reader,writer) 元组