Async socket server and ports

[Pengwyn]

Hi guys, first time posting on the Python forums

I am wondering how do asynchronous socket servers go about maintaining so many clients, specifically, how can the server have more than one client in a connected TCP stream if it is on a single port, or is there some automagical stuff happening to assign different ports behind the scenes?

for example in the doceumentation at
https://docs.python.org/3.7/library/asyn...-based-api
the server is serving on port 8888, however this expects multiple clients to have connections.

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import asyncio   async def handle_echo(reader, writer):     data = await reader.read(100)     message = data.decode()     addr = writer.get_extra_info('peername')       print(f"Received {message!r} from {addr!r}")       print(f"Send: {message!r}")     writer.write(data)     await writer.drain()       print("Close the connection")     writer.close()   async def main():     server = await asyncio.start_server(         handle_echo, '127.0.0.1', 8888)       addr = server.sockets[0].getsockname()     print(f'Serving on {addr}')       async with server:         await server.serve_forever()   asyncio.run(main())

Thanks

[DeaD_EyE]

With a trick the developers made asynchronous code looking like synchronous code.
They use generators with the send function, which allows to delegate everything.

It's a combination of:

• DefaultSelector, which uses select, epoll and other os related selectors for sockets
  
• Generators (await was before yield from, async was previously a normal generator with a yield statement used with send from outside)
  
• EventLoop, which is asyncio.run_forever()
  

If you want to dig deeper in asyncio, you should watch some talks on YouTube.
Some of them are explaining it very deep.