Course of Raku / Functional, concurrent, reactive, and web programming / Web programming / A simple HTTP server

Listening for connections

To act as a server, create a socket in listening mode with the :listen argument, giving the address and port to listen on:

my $listener = IO::Socket::INET.new(
    :listen,
    :localhost('127.0.0.1'),
    :localport(8080),
);

:localhost('127.0.0.1') listens on your own machine, and :localport(8080) is the port clients must connect to. The socket is now waiting, but no client has arrived yet.

To take the next incoming connection, call .accept. It blocks until a client connects, then returns a fresh socket representing that one conversation:

my $conn = $listener.accept;
say 'a client connected';

The $listener keeps listening for more clients, while $conn is your channel to talk to this particular one. A real server calls .accept in a loop, handling each client as it arrives.

These examples run on your own machine; connect to them from a browser or another program at 127.0.0.1:8080.

So a server is just a socket turned around: instead of :host/:port to dial out, you give :listen with :localhost/:localport to wait for calls in.

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