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![REQUESTS
import requests
r = requests.get('https://api.github.com/user',
auth=('user', 'pass'))
print(r.status_code)
print(r.headers['content-type'])
print(r.text)](https://image.slidesharecdn.com/andrewsvetlovasyncio-160330064649/85/slide-9-320.jpg)
![AIOHTTP
import aiohttp
async def coro():
r = await aiohttp.get('https://api.github.com/user',
auth=aiohttp.BasicAuth('user', 'pass'))
print(r.status)
print(r.headers['content-type'])
print(await r.text())
r.close()](https://image.slidesharecdn.com/andrewsvetlovasyncio-160330064649/85/slide-10-320.jpg)
![DJANGO
from django.conf.urls import url
from django.http import HttpResponse
def index(request):
return HttpResponse("Hello, world")
urlpatterns = [
url(r'^$', index),
]](https://image.slidesharecdn.com/andrewsvetlovasyncio-160330064649/85/slide-17-320.jpg)
![TORNADO
import tornado.ioloop
import tornado.web
class MainHandler(tornado.web.RequestHandler):
def get(self):
self.write("Hello, world")
app = tornado.web.Application([
(r"/", MainHandler)])
app.listen(8888)
tornado.ioloop.IOLoop.current().start()](https://image.slidesharecdn.com/andrewsvetlovasyncio-160330064649/85/slide-19-320.jpg)
![ПОДКЛЮЧЕНИЕ БД
import sqlalchemy as sa
from aiopg.sa import create_engine
metadata = sa.MetaData()
tbl = sa.Table('tbl', metadata,
sa.Column('id', sa.Integer, primary_key=True),
sa.Column('val', sa.String(255)))
app['db'] = await create_engine(...)
async def close_db(app):
app['db'].close()
await app['db'].wait_closed()
app.on_cleanup.append(close_db)](https://image.slidesharecdn.com/andrewsvetlovasyncio-160330064649/85/slide-20-320.jpg)
![ЗАПРОСЫ В БД
async def handler(request):
txt = ""
async with request.app['db'].acquire() as conn:
await conn.execute(tbl.insert().values(val='abc'))
async for row in conn.execute(tbl.select()):
txt += "{}: {}n".format(row.id, row.val)
return web.Response(text=txt)](https://image.slidesharecdn.com/andrewsvetlovasyncio-160330064649/85/slide-21-320.jpg)
![СЕРВЕРНЫЕ СЕССИИ
from aiohttp_session import get_session
async def hander(request):
session = await get_session(request)
session['key'] = 'value'
return web.Response()](https://image.slidesharecdn.com/andrewsvetlovasyncio-160330064649/85/slide-25-320.jpg)
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Андрей Светлов
Документ рассматривает асинхронные сетевые приложения на Python, обсуждая использование библиотеки asyncio и её производные, такие как aiohttp. В нем приводятся примеры работы с асинхронными веб-сервисами, включая подключение к базам данных и обработку веб-сокетов, а также приводятся правила и советы для разработки с использованием asyncio. Кроме того, упоминаются вопросы производительности и возможности масштабирования для высоконагруженных приложений.
Андрей Светлов
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- 9. REQUESTS import requests r =requests.get('https://api.github.com/user', auth=('user', 'pass')) print(r.status_code) print(r.headers['content-type']) print(r.text)
- 10. AIOHTTP import aiohttp async defcoro(): r = await aiohttp.get('https://api.github.com/user', auth=aiohttp.BasicAuth('user', 'pass')) print(r.status) print(r.headers['content-type']) print(await r.text()) r.close()
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- 12. REQUESTS С СЕССИЕЙ session = requests.Session() r= session.get(url)
- 13. AIOHTTP С СЕССИЕЙ session = aiohttp.ClientSession() asyncdef coro(session): async with session.get(url) as r: print(r.status) print(await r.text())
- 14. ТАЙМАУТЫ async def coro(session): withaiohttp.Timeout(1.5): async with session.get(url) as r: ...
- 15. ВЕБСОКЕТЫ async with client.ws_connect( 'http://websocket-server.org/endpoint')as ws: async for msg in ws: if msg.data == 'close': await ws.close() break else: ws.send_str("Answer on " + msg.data)
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- 17. DJANGO from django.conf.urls importurl from django.http import HttpResponse def index(request): return HttpResponse("Hello, world") urlpatterns = [ url(r'^$', index), ]
- 18. AIOHTTP from aiohttp importweb async def handler(request): return web.Response(text="Hello, world") app = web.Application(loop=loop) app.router.add_route('GET', '/', handler) web.run_app(app)
- 19. TORNADO import tornado.ioloop import tornado.web classMainHandler(tornado.web.RequestHandler): def get(self): self.write("Hello, world") app = tornado.web.Application([ (r"/", MainHandler)]) app.listen(8888) tornado.ioloop.IOLoop.current().start()
- 20. ПОДКЛЮЧЕНИЕ БД import sqlalchemy assa from aiopg.sa import create_engine metadata = sa.MetaData() tbl = sa.Table('tbl', metadata, sa.Column('id', sa.Integer, primary_key=True), sa.Column('val', sa.String(255))) app['db'] = await create_engine(...) async def close_db(app): app['db'].close() await app['db'].wait_closed() app.on_cleanup.append(close_db)
- 21. ЗАПРОСЫ В БД async def handler(request): txt= "" async with request.app['db'].acquire() as conn: await conn.execute(tbl.insert().values(val='abc')) async for row in conn.execute(tbl.select()): txt += "{}: {}n".format(row.id, row.val) return web.Response(text=txt)
- 22. СЕРВЕРНЫЕ ВЕБСОКЕТЫ async def handler(request): ws= web.WebSocketResponse() await ws.prepare(request) async for msg in ws: if msg.data == 'close': await ws.close() break else: ws.send_str(msg.data + '/answer') return ws
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- 25. СЕРВЕРНЫЕ СЕССИИ from aiohttp_session importget_session async def hander(request): session = await get_session(request) session['key'] = 'value' return web.Response()
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- 31. ИТЕРАЦИЯ EVENT LOOP def run_forever(): while True: events= selector.select(timeout) for key, mask in events: if mask & EVENT_READ: key.reader(key.fileobj) if mask & EVENT_WRITE: key.writer(key.fileobj) for handler in ready: handler._run()
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- 36. PYTHONASYNCIODEBUG=1 async def f(): fut= asyncio.Future() fut.set_exception(RuntimeError()) del fut ... ERROR:asyncio:Future exception was never retrieved future: Future finished exception=RuntimeError() RuntimeError
- 37. $ PYTHONASYNCIODEBUG=x pythonmyapp.py ERROR:asyncio:Future exception was never retrieved future: Future finished exception=RuntimeError() created at filename.py:10 source_traceback: Object created at (most recent call last): ... File "filename.py", line 10, in f fut = asyncio.Future() RuntimeError
- 38. EXPLICIT LOOP def request(method, url,*, loop=None): ... loop = asyncio.get_event_loop() await request('GET', 'http://python.org', loop=loop)
- 39. ТЕСТИРОВАНИЕ class Test(unittest.TestCase): def setUp(self): self.loop= asyncio.new_event_loop() asyncio.set_event_loop(None) def tearDown(self): self.loop.close() def test_func(self): async def go(): self.assertEqual(1, await func(loop=loop)) self.loop.run_until_complete(go())
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