Greetings and a merry christmas everyone,
I come to you tonight because I am encountering quit a hurdle in my understanding.
I recently started playing an online game which requires the player to code programs that interacts with a server api. After getting to know said API I discovered one could use websockets. So on I went, rummaging through my local CPAN distributor for the right module, trying this or that until I found AnyEvent::Websocket::Client.
This is my first time with event driven programming so please bear with my ignorance:
Update: From what I understand, once this is called, an event loop is entered and everything happens in the callback routine
I rewrote my code following this behaviour and it got working.
Now, what if I need to keep an eye on two event loops?
Do I need to spawn a new process and have it pipe data to me?
I am thinking about something along those lines:
- Receive data from one websocket, depending on that data act upon it
- Receive data from another websocket to learn how what I did changed the system state
from where I stand a possible solution would be:
1 Acting process that spawns two websocket listening children, each child openend with a handle so the father can use the diamond operator.
Now a real mindfuck: what design to choose from:
1) a shared variable referencing my local copy of the overall system state, which gets updated by both processes and periodically checked by their father?
2) a pipe system from the children to their father that feeds him new info?
#this code should block if nothing comes from child 2 and during that
+time it
#may receive data from child1 that wont be acted upon
while(<$child1>){
try something...will block if nothing comes from child 1
my $line = <$child2>
while(!defined $line){
$line = <$child2>;
do something else
}
}
Old code
while(1){
print "recving\n";
my $hash = $trader->{venues}->{$venues[0]}->{ticker_tape}->recv;
print "recved\n";
my $parsed = parse_json($hash);
print "\n" x 5;
print "$hash";
print "\n" x 5;
}
from what I understand, this code should block on the line begining with
"my hash, such and such"
until it receives the signal from the following snippet:
$self->{venues}->{$i}->{client} = AnyEvent::WebSocket::Client->new
+;
my $cv = $self->{venues}->{$i}->{client}->connect("wss://api.s
+tockfighter.io/ob/api/ws/$self->{account}/venues/$i/tickertape")->cb(
+sub{
our $connection = eval { shift->recv };
if($@) {
warn $@;
return;
}
$connection->on(each_message => sub {
my($connection, $message) = @_;
my $decode = parse_json($message->{body});
print "got a message ticker!\n";
$self->{venues}->{$i}->{ticker_tape}->send($message
+->{body});
});
$connection->on(finish => sub {
# $connection is the same connection object
my($connection) = @_;
$connection->close;
});
});
said signal containing a json string.
Thing is: I only receive ONE string, the message
"got a message ticker"
appears only once which indicates that the callback is only called the first time. then the message gets repeated over and over afterward. I think I am missing some important concept regarding this type of programming and I would be most grateful if someone could point it out.
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