from time import sleep
import asyncio

async def request(url):
  print('正在請(qǐng)求url')
  sleep(2)
  print('下載成功')

# 返回一個(gè)特殊的協(xié)程對(duì)象，request函數(shù)內(nèi)部不會(huì)被執(zhí)行
c = request('www.baidu.com')

# 實(shí)例化一個(gè)事件循環(huán)對(duì)象
loop = asyncio.get_event_loop()

# 基于事件循環(huán)對(duì)象創(chuàng)建一個(gè)任務(wù)對(duì)象,并將協(xié)程對(duì)象封裝到該對(duì)象中
task = loop.create_task(c)

# 另一種形式實(shí)例化任務(wù)對(duì)象的方法
task = asyncio.ensure_future(c)

# 將協(xié)程對(duì)象注冊(cè)到事件循環(huán)對(duì)象中，并需要啟動(dòng)事件循環(huán)對(duì)象
# 當(dāng)事件循環(huán)對(duì)象內(nèi)的第一個(gè)參數(shù)遇到阻塞是，就會(huì)自動(dòng)執(zhí)行后面的對(duì)象，當(dāng)?shù)谝粋€(gè)對(duì)象的阻塞結(jié)束是會(huì)上報(bào)給事件循環(huán)對(duì)象，然后事件循環(huán)對(duì)象繼續(xù)執(zhí)行第一個(gè)對(duì)象，從而達(dá)到異步的效果
loop.run_until_complete(task)

import asyncio

async def request(url):
  print('正在請(qǐng)求url')
  print('下載成功')
  return url

# 回調(diào)函數(shù)必須有一個(gè)參數(shù)：task【任務(wù)對(duì)象】
# task.result()：任務(wù)對(duì)象中封裝的協(xié)程對(duì)象對(duì)應(yīng)的特殊函數(shù)內(nèi)部的返回值
def callback(task):
  print('this is callback')
  print(task.result())

c = request('www.baidu.com')
# 創(chuàng)建一個(gè)任務(wù)對(duì)象
task = asyncio.ensure_future(c)
# 給任務(wù)對(duì)象綁定一個(gè)回調(diào)函數(shù)
task.add_done_callback(callback)
# 實(shí)例化一個(gè)事件循環(huán)對(duì)象
loop = asyncio.get_event_loop()
# 將協(xié)程對(duì)象注冊(cè)到事件循環(huán)對(duì)象中，并需要啟動(dòng)事件循環(huán)對(duì)象
loop.run_until_complete(task)

import asyncio
import time

urls = ['www.baidu.com','www.sogou,com','www.goubanjia.com']
start_time = time.time()
async def request(url):
  print('正在請(qǐng)求url')
  # 在多任務(wù)異步協(xié)程事項(xiàng)中，不可以出現(xiàn)不支持異步的相關(guān)代碼，sleep不支持
  # sleep(2)
  await asyncio.sleep(2)
  print('下載成功')

loop = asyncio.get_event_loop()
# 任務(wù)列表：防止多個(gè)任務(wù)對(duì)象
tasks = []
for url in urls:
  c = request(url)
  task = asyncio.ensure_future(c)
  tasks.append(task)

loop.run_until_complete(asyncio.wait(tasks))
print(time.time() - start_time)

# aiohttp:支持異步的一個(gè)基于網(wǎng)絡(luò)請(qǐng)求的模塊
import aiohttp
import asyncio
import time

urls = ['http://127.0.0.1:5000/jay',
    'http://127.0.0.1:5000/bobo',
    'http://127.0.0.1:5000/tom',]

start_time = time.time()

async def get_pageText(url):
  async with aiohttp.ClientSession() as s:# 實(shí)例化請(qǐng)求對(duì)象
    async with await s.get(url) as response:
      page_text = await response.text()
      print(page_text)
      # 這里有返回值，是因?yàn)橐没卣{(diào)函數(shù)進(jìn)行數(shù)據(jù)解析
      return page_text

# 封裝回調(diào)函數(shù)用于數(shù)據(jù)解析
def parse(task):
  # 1.獲取相應(yīng)數(shù)據(jù)
  page_text = task.reault()
  print(page_text+'，即將進(jìn)行數(shù)據(jù)解析...')
  # 以下解析操作


tasks = []
for url in urls:
  c = get_pageText(url)
  task = asyncio.ensure_future(c)
  # 給任務(wù)對(duì)象綁定回調(diào)函數(shù)用于數(shù)據(jù)解析
  task.add_done_callback(parse)
  tasks.append(task)

loop = asyncio.get_event_loop()
loop.run_until_complete(asyncio.wait(tasks))
print(time.time() - start_time)