How to receive just one line from an IO::Socket::Async in Raku?

Question

So, I have this:

    my $conn = await IO::Socket::Async.connect('127.0.0.1', 12340);  
    $conn.print: "GET /rest HTTP/1.1\r\n\r\n";

How to receive just the first line from the server ?

I could use whenever and put some logic in it, but there's a simpler way, right ?

Answer 1

If you really only want the first line, and don't care about the rest of the response, then you can do this:

my $first-line = await $conn.Supply.lines.first;

That is, get the Supply representing the response stream, have it split into lines (which results in a Supply of lines), and take the first line that arrives. Any data received beyond the first line will be discarded.

IO::Socket::Async works in terms of providing packets of data as they arrive. It doesn't get into providing a line-oriented interface; if a protocol really is so simple as reading line by line, then a react whenever $conn.Supply.lines -> $line { } will do it (and handles lines split over packets correctly).