Fully-functional Event Loop in 100 Lines of Python
Check out the series about the event loop on my blog Explain event loop in 100 lines of code and From Callback Hell to async/await Heaven.
Example using callback-style:
import socket as _socket
class EventLoop: pass
class Context: pass
class socket(Context): pass
def main(serv_addr):
sock = socket(_socket.AF_INET, _socket.SOCK_STREAM)
def _on_conn(err):
if err:
raise err
def _on_sent(err):
if err:
sock.close()
raise err
def _on_resp(err, resp=None):
sock.close()
if err:
raise err
print(resp)
sock.recv(1024, _on_resp)
sock.sendall(b'foobar', _on_sent)
sock.connect(serv_addr, _on_conn)
if __name__ == '__main__':
event_loop = EventLoop()
Context.set_event_loop(event_loop)
serv_addr = ('127.0.0.1', int(sys.argv[1]))
event_loop.run(main, serv_addr)Give it a try:
# server
> python server.py 53210
# client
> python event_loop.py 53210Example using async-await-like style:
import socket as _socket
class EventLoop: pass
class Context: pass
class socket(Context): pass
def http_get(sock):
try:
yield sock.sendall(b'GET / HTTP/1.1\r\nHost: t.co\r\n\r\n')
return sock.recv(1024)
finally:
sock.close()
def main(serv_addr):
sock = socket(AF_INET, SOCK_STREAM)
yield sock.connect(serv_addr)
resp = yield http_get(sock)
print(resp)
if __name__ == '__main__':
event_loop = EventLoop()
Context.set_event_loop(event_loop)
serv_addr = ('t.co', 80)
event_loop.run(main)Give it a try:
> python event_loop_gen.py 53210