Use AnyEvent to stand up a TLS server

I have written select based TLS servers before, but I want to do it the right way, by using AnyEvent and an event loop.

So first here is a TLS client that works with another TLS server I wrote using select.

Writer.pl, connects to the server and sends 3 short messages and disconnects

#!/usr/bin/env perl

use strict;
use warnings;

use AnyEvent;
use AnyEvent::Log;
use AnyEvent::Handle;
use AnyEvent::Socket;
use EV;

use Data::Dumper;

$AnyEvent::Log::FILTER->level ("trace");

my $handle;

my @queue;

tcp_connect "127.0.0.1", 9999, sub {
    my ($fh) = @_;

    print "Before push_write\n";
    push (@queue, "XX\n");
    push (@queue, "YY\n");
    push (@queue, "ZZ\n");
    print "After push_write\n";

    $handle = new AnyEvent::Handle (
        fh => $fh,
        tls => "connect",
        tls_ctx => { verify => 0 },
        on_error => sub {
            my ($xhandle, $fatal, $message) = @_;

            print "on_error: ($xhandle) ($fatal) ($message)\n";

            exit 1;
        },
        on_eof => sub {
            my ($handle) = @_;

            print "on_eof:\n";
            exit 0;
        },
        on_drain => sub {
            my ($handle) = @_;

            print "on_drain:\n";
            if (@queue)
            {
                my $write = shift @queue;
                print "Write :$write";
                $handle->push_write ($write);
            }
            else
            {
                print "Queue is empty\n";
                $handle->push_shutdown ();
            }
        },
        on_starttls => sub {
            my ($handle, $success, $error) = @_;

            print "on_starttls ($success) ($error)\n";

            return;
        }
    );
};

EV::run;
[download]

This works with an IO::Select based server.

Now to create the TLS server via AnyEvent

I metacpan'd my fingers till they bled, to find working example code. But Alas I could not get it to work, and I have no idea what I am doing, not doing or just am an idiot with.

Using the Metacpan article for AnyEvent::Handle, in the NONFREQUENTLY-ASKED-QUESTIONS, there is a small snippet that seems that it should work.

tcp_server undef, $port, sub {
   my ($fh) = @_;
 
   my $handle = new AnyEvent::Handle
      fh       => $fh,
      tls      => "accept",
      tls_ctx  => { cert_file => "my-server-keycert.pem" },
      ...
[download]

So here is my attempt to write it into a server.

Server4.pl

#!/usr/bin/env perl

use strict;
use warnings;

use Data::Dumper;

use AnyEvent;
use AnyEvent::Handle;
use AnyEvent::Socket;
use AnyEvent::Log;

use IO::Socket::SSL;

use EV;

use Cpanel::JSON::XS;
use Path::Tiny qw(path);

$IO::Socket::SSL::DEBUG = 3;
$AnyEvent::Log::FILTER->level ("trace");

my $json_obj = Cpanel::JSON::XS->new->ascii->pretty(1)->allow_nonref;

my $config_file = Path::Tiny::path ("config.json");
die "Must have config file" if (!$config_file->exists);

my $config_raw = $config_file->slurp ();
my $config;

my $ret = eval {
    $config = $json_obj->decode ($config_raw);
};

if (!$ret) {
    die "Error Parsing JSON\n$@\n";
}

tcp_server $config->{LocalAddr}, $config->{LocalPort}, sub {
    my ($fh) = @_;

    print "host started\n";

    my $handle = new AnyEvent::Handle (
        fh           => $fh,
        tls          => "accept",
        tls_ctx      => {
            cert_file => $config->{cert_file},
            key_file => $config->{key_file}
        },
        on_read      => sub {
            my ($handle) = @_;

            print "ON_READ :" . $handle->{rbuf} . ":\n";
        },
        on_eof       => sub {
            my ($handle) = @_;

            print "ON_EOF\n";
        },
        on_error     => sub {
            my ($handle, $fatal, $message) = @_;

            print "ON_ERROR ($fatal) ($message)\n";
        },
    );

    print "Handle created :$handle:\n";
};

print "Loop started\n";
EV::run;
[download]

So when I run it, I see Loop Started, and netstat -anop says it is listening on 127.0.0.1:9999, per the config file. I see the message "Loop Started".

In another window I start Writer.pl

I get the server messages "host started" and "Handle created"

Writer.pl tries to Write XX the first of 3 short messages, then gets an on_eof. And exits out of the program.

Here is the server side of the window output

julian@work:~/git/LLMAssistant/reference/server$ ./Server4.pl
2023-08-17 19:18:28.000000 -0500 info  AnyEvent: Autodetected model 'A
+nyEvent::Impl::EV', using it.
Loop started
host started
Handle created :AnyEvent::Handle=HASH(0x555b2b5d6eb0):
host started
Handle created :AnyEvent::Handle=HASH(0x555b2aa87610):
host started
Handle created :AnyEvent::Handle=HASH(0x555b2aa876d0):
^C
[download]

Here is the output of the client side window

julian@work:~/git/LLMAssistant/reference/client$ ./Writer.pl 
2023-08-17 19:18:32.000000 -0500 info  AnyEvent: Autodetected model 'A
+nyEvent::Impl::EV', using it.
Before push_write
After push_write
on_drain:
Write :XX
on_eof:
julian@work:~/git/LLMAssistant/reference/client$ ./Writer.pl 
2023-08-17 19:18:33.000000 -0500 info  AnyEvent: Autodetected model 'A
+nyEvent::Impl::EV', using it.
Before push_write
After push_write
on_drain:
Write :XX
on_eof:
julian@work:~/git/LLMAssistant/reference/client$ ./Writer.pl 
2023-08-17 19:18:35.000000 -0500 info  AnyEvent: Autodetected model 'A
+nyEvent::Impl::EV', using it.
Before push_write
After push_write
on_drain:
Write :XX
on_eof:
[download]

My config file is:

{
    "LocalAddr": "127.0.0.1",
    "LocalPort": 9999,
    "cert_file": "cert.pem",
    "key_file": "key.pem"
}
[download]

The cert and key are self signed cert files

Any advice?

On how I can get this to work?

In reply to Using AnyEvent to create a TLS server by Bodger

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