Add basic signaling server

With this, VROOM is now its own signaling server and do not rely on SignalMaster anymore, which means NodeJS isn't required anymore
There are some downside, for now, only websocket transport is supported, there's no fallback

vroom.pl

@@ -19,6 +19,8 @@ use Session::Token;
 use Config::Simple;
 use Email::Valid;
 use URI;
+use Protocol::SocketIO::Handshake;
+use Protocol::SocketIO::Message;
 use Data::Dumper;
 
 app->log->level('info');
@@ -73,9 +75,12 @@ if ($config->{'etherpad.uri'} =~ m/https?:\/\/.*/ && $config->{'etherpad.api_key
   }
 }
 
-# GLobal error check
+# Global error check
 our $error = undef;
 
+# Global client hash
+our $socket_peers = {};
+
 # Load I18N, and declare supported languages
 plugin I18N => {
   namespace => 'Vroom::I18N',
@@ -1036,6 +1041,152 @@ helper key_can_do_this => sub {
   return 0;
 };
 
+# Socket.IO handshake
+get '/socket.io/:ver' => sub {
+  my $self = shift;
+  $self->session(peer_id => $self->get_random(256));
+  my $handshake = Protocol::SocketIO::Handshake->new(
+      session_id        => $self->session('peer_id'),
+      heartbeat_timeout => 15,
+      close_timeout     => 20,
+      transports        => [qw/websocket/]
+  );
+  return $self->render(text => $handshake->to_bytes);
+};
+
+# WebSocket transport for the Socket.IO channel
+websocket '/socket.io/:ver/websocket/:id' => sub {
+  my $self = shift;
+  my $id = $self->stash('id');
+  if ($id ne $self->session('peer_id') || !$self->session('name')){
+    $self->app->log->debug('Sometyhing is wrong, peer ID is ' . $id . ' but should be ' . $self->session('peer_id'));
+    return $self->send('Bad session');
+  }
+
+  $socket_peers->{$id}->{socket} = $self->tx;
+  $socket_peers->{$id}->{last} = time;
+
+  $self->on('message' => sub {
+    my $self = shift;
+    my $msg = Protocol::SocketIO::Message->new->parse(shift);
+
+    if ($msg->type eq 'event'){
+      if ($msg->{data}->{name} eq 'join'){
+        my $room = $msg->{data}->{args}[0];
+        my $others = {};
+        foreach my $peers (keys %$socket_peers){
+          next if ($peers eq $id);
+          $others->{$peers} = $socket_peers->{$peers}->{details};
+        }
+        $socket_peers->{$id}->{details} = {
+          screen => \0,
+          video  => \1,
+          audio  => \0
+        };
+        $socket_peers->{$id}->{room} = $room;
+        $self->app->log->debug("client ID " . $id . " joined room " . $room);
+#        $self->app->log->debug(Dumper($others));
+        $self->send(
+          Protocol::SocketIO::Message->new(
+            type       => 'ack',
+            message_id => $msg->{id},
+            args => [
+              undef,
+              {
+                clients => $others
+              }
+            ]
+          )
+        );
+      }
+      elsif ($msg->{data}->{name} eq 'message'){
+        my $room = $socket_peers->{$id}->{room};
+        $self->app->log->debug("Message received from " . $id);
+        foreach my $peer (keys %$socket_peers){
+          next if ($peer eq $id);
+          next if $socket_peers->{$peer}->{room} ne $room;
+          #$self->app->log->debug("Relaying message from " . $id . " to " . $peer);
+          $msg->{data}->{args}[0]->{from} = $id;
+          #$self->app->log->debug(Dumper($msg));
+          $socket_peers->{$peer}->{socket}->send(
+            Protocol::SocketIO::Message->new(%$msg)
+          );
+        }
+      }
+      elsif ($msg->{data}->{name} eq 'shareScreen'){
+        $socket_peers->{$id}->{details}->{screen} = \1;
+      }
+      elsif ($msg->{data}->{name} eq 'unshareScreen'){
+        $socket_peers->{$id}->{details}->{screen} = \0;
+        foreach my $peer (keys %$socket_peers){
+          next if ($peer eq $id);
+          next if $socket_peers->{$peer}->{room} ne $socket_peers->{$id}->{room};
+          $self->app->log->debug("Notifying $peer that $id unshared its screen");
+          $socket_peers->{$peer}->{socket}->send(
+            Protocol::SocketIO::Message->new(
+              type => 'event',
+              data => {
+                name => 'remove',
+                args => [
+                  {
+                    id   => $id,
+                    type => 'screen'
+                  }
+                ]
+              }
+            )
+          );
+        }
+      }
+    }
+    elsif ($msg->type eq 'heartbeat'){
+      # Heartbeat reply, update timestamp
+      $socket_peers->{$id}->{last} = time;
+    }
+  });
+
+  $self->on(finish => sub {
+    my ($self, $code, $reason) = @_;
+    $self->app->log->debug("Client id " . $id . " closed websocket connection");
+    foreach my $peer (keys %$socket_peers){
+      next if ($peer eq $id);
+      next if $socket_peers->{$peer}->{room} ne $socket_peers->{$id}->{room};
+      $self->app->log->debug("Relaying message from " . $id . " to " . $peer);
+      $socket_peers->{$peer}->{socket}->send(
+        Protocol::SocketIO::Message->new(
+          type => 'event',
+          data => {
+            name => 'remove',
+            args => [
+              {
+                id   => $id,
+                type => 'video'
+              }
+            ]
+          }
+        )
+      );
+    }
+    delete $socket_peers->{$id};
+  });
+  $self->send(Protocol::SocketIO::Message->new( type => 'connect' ));
+};
+
+# Send heartbeats to all websocket clients
+Mojo::IOLoop->recurring( 2 => sub {
+  foreach my $peer ( keys %$socket_peers ) {
+    if ($socket_peers->{$peer}->{last} < time - 10){
+      app->log->debug("Peer $peer didn't reply in 10 sec, disconnecting");
+      $socket_peers->{$peer}->{socket}->finish;
+    }
+    else {
+      $socket_peers->{$peer}->{socket}->send(
+        Protocol::SocketIO::Message->new( type => 'heartbeat' )
+      );
+    }
+  }
+});
+
 # Route / to the index page
 get '/' => sub {
   my $self = shift;