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@dabeaz
Last active October 17, 2023 03:26
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Live-coded examples from my PyCon Brasil 2015 Keynote
# aecho.py
from socket import *
import asyncio
loop = asyncio.get_event_loop()
async def echo_server(address):
sock = socket(AF_INET, SOCK_STREAM)
sock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
sock.bind(address)
sock.listen(5)
sock.setblocking(False)
while True:
client, addr = await loop.sock_accept(sock)
print('Connection from', addr)
loop.create_task(echo_handler(client))
async def echo_handler(client):
with client:
while True:
data = await loop.sock_recv(client, 10000)
if not data:
break
await loop.sock_sendall(client, b'Got:'+data)
print('Connection closed')
loop.create_task(echo_server(('',25000)))
loop.run_forever()
from socket import *
import time
def benchmark(addr, nmessages):
sock = socket(AF_INET, SOCK_STREAM)
sock.connect(addr)
start = time.time()
for n in range(nmessages):
sock.send(b'x')
resp = sock.recv(10000)
end = time.time()
print(nmessages/(end-start), 'messages/sec')
benchmark(('localhost',25000), 100000)
# pecho.py
from socket import *
import play
loop = play.Loop()
async def echo_server(address):
sock = socket(AF_INET, SOCK_STREAM)
sock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
sock.bind(address)
sock.listen(5)
sock.setblocking(False)
while True:
client, addr = await loop.sock_accept(sock)
print('Connection from', addr)
loop.create_task(echo_handler(client))
async def echo_handler(client):
with client:
while True:
data = await loop.sock_recv(client, 10000)
if not data:
break
await loop.sock_sendall(client, b'Got:'+data)
print('Connection closed')
loop.create_task(echo_server(('',25000)))
loop.run_forever()
# play.py
from types import coroutine
from collections import deque
from selectors import DefaultSelector, EVENT_READ, EVENT_WRITE
@coroutine
def read_wait(sock):
yield 'read_wait', sock
@coroutine
def write_wait(sock):
yield 'write_wait', sock
class Loop:
def __init__(self):
self.ready = deque()
self.selector = DefaultSelector()
async def sock_recv(self, sock, maxbytes):
await read_wait(sock)
return sock.recv(maxbytes)
async def sock_accept(self, sock):
await read_wait(sock)
return sock.accept()
async def sock_sendall(self, sock, data):
while data:
try:
nsent = sock.send(data)
data = data[nsent:]
except BlockingIOError:
await write_wait(sock)
def create_task(self, coro):
self.ready.append(coro)
def run_forever(self):
while True:
while not self.ready:
events = self.selector.select()
for key, _ in events:
self.ready.append(key.data)
self.selector.unregister(key.fileobj)
while self.ready:
self.current_task = self.ready.popleft()
try:
op, *args = self.current_task.send(None) # Run to the yield
getattr(self, op)(*args) # Sneaky method call
except StopIteration:
pass
def read_wait(self, sock):
self.selector.register(sock, EVENT_READ, self.current_task)
def write_wait(self, sock):
self.selector.register(sock, EVENT_WRITE, self.current_task)
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