Screen – Matthew Lancellotti

Screen is a web portal to the terminal! More importantly, it is a collaboration tool that allows users to share a terminal session online.

The Screen website is no longer active. There are issues with piping information back and forth to a terminal, especially in interactive CLI’s. There are also security issues, so I have decommissioned it. But this was still a great learning experience.

You can view the full code on GitHub. The below preview is the room.pm module. It creates room objects for users to collaborate in. It also creates a shell for each room and executes the terminal commands.

package room;

use strict; use warnings;
use feature 'switch';
use helpers;
use set;
use shell;

######################################### GLOBALS ########################################
our %nametoroom = ();

#################################### HELPER FUNCTIONS ####################################
our @namepool = ();
open( my $FH, '&lt;', 'public/lexis.txt' ) or die 'Could not open the lexis!!!'; push @namepool =&gt; trim(lc $_) while( &lt;$FH&gt; ); # rooms are stored as lowercase, so the keys must be lc too!
close( $FH ) or die 'Could not CLOSE the lexis!';

sub rand_name{
    my $randindex = int( $#namepool * rand() );
    return $namepool[$randindex]
}

sub name_to_room{ # creates a new room if necessary
    my ($name) = @_;
    return $nametoroom{$name} //= room-&gt;new(name=&gt;$name) or die 'Bad room name string!' # adds the room to our hash if necessary
}

sub htmlify{ # this takes any amount of terminal stdout and converts it to html.
	my ( $str, $prompt ) = @_;
	# put a span around the commands...
	# $prompt = quotemeta $prompt;
	# $str =~ s|^(.*)\n|<span class="command">$1</span>\n|; # the very first command is NOT preceded by a prompt.
	# $str =~ s|\n?$prompt(.*)\n|\n<span class="command">$1</span>\n|g; # this also makes sure that prompts always start on new lines.
	# $str =~ s|\n?$prompt$|\n|; # delete final prompt.  Also, all endings have newlines regardless of what bash outputted.
	# $str =~ s|\n$|\n\n|g; # for an outputless command, let's display an empty line to show that.
	$str =~ s|\n|
|g;
	return $str
}

######################################## NEW ROOM ########################################
sub new{
	my $packagename = shift;
	my %options = @_; # includes the NAME of the room.

	my $room = bless {
		name =&gt; $options{name},
		shell =&gt; undef,
		controllers =&gt; set-&gt;new,
		output =&gt; '',
	}
	=&gt; $packagename;

	$room-&gt;shell('sh');

	return $room
}

########################################## ROOM ##########################################
sub name{
	my $room = shift;
	return $room{name}
}

sub shell{
	my $room = shift;
	my ($shellname) = @_;
	if( defined $shellname ){
		$room-&gt;shell-&gt;close if defined $room-&gt;shell;
		$room{shell} = shell-&gt;new( $shellname, $room );
		my $divider = "\n###############################################################\n";
		$room-&gt;append($divider."Welcome to a new $shellname shell!\n\n");
	}
	return $room{shell}
}

sub controllers{ # this is a SET of controllers
	my $room = shift;
	return $room{controllers}
}
sub add_controller{
	my $room = shift;
	my ($controller) = @_;
	$room-&gt;controllers-&gt;add_element($controller)
}
sub remove_controller{ say 'removing a controller...';
	my $room = shift;
	my ($controller) = @_;
	$room-&gt;controllers-&gt;remove_element($controller);
	# check if the room is empty.  if so, close the room.
	if( $room-&gt;controllers-&gt;is_empty ){ say 'closing the room...'; $room-&gt;close }
}

sub output{ # gets all the output of a room for a new self joining in
	my $room = shift;
	return $room{output}
}

sub append_to_output{
	my $room = shift;
	my ($string) = @_;
	$room{output} .= $string;
}

sub append{
	my $room = shift;
	my ($string) = @_;
	$room-&gt;append_to_output($string);
#	my $html = htmlify( $string, $room-&gt;shell-&gt;prompt );
	my $html = htmlify( $string );
	$room-&gt;jblast( command=&gt;'append', output=&gt;$html );
	#say "output is now $room{output}";
}

sub jblast{ # blast is replaced with jblast, which includes the json in it
	my $room = shift;
	#say 'jblasting to '.scalar $room-&gt;controllers-&gt;array.' controllers.';
	my %ball = @_; say 'ball is '."@_";
	foreach( $room-&gt;controllers-&gt;array ){ #say 'i have a controller '."$_";
		$_-&gt;jsend(%ball)
	}
	#say 'done WITH CONTROLLERS';
}

use overload
	'""' =&gt; \&amp;stringify;

sub stringify{
	my $room = shift;
	my $toprint;
	{
	local $" = ',';
		$toprint .= 'Roomname is '.$room-&gt;name."\n";
		my @controllers = $room-&gt;controllers-&gt;array; $toprint .= "Controllers are: @controllers\n";
	}
	return $toprint
}

sub command{ # executes a shell command and relays the output to all controllers.
	my $room = shift;
	my ($command) = @_; # incoming command does not have a \n at the end.
	say "command is $command"; #say "Bin is $Bin";
	if( $command =~ /^(shell) +([^ ]*)/i ){ # capture special room commands: shells
		my $keyword = $1;
        my $argument = lc trim $2;
        given($keyword){
	        when('shell'){ # the argument has already been verified in $self-&gt;command
	            $room-&gt;shell($argument);
	            $room-&gt;jblast( command=&gt;'set', id=&gt;'shellname', html=&gt;$argument, color=&gt;"#f12772" );
	        }
	    }
    }
    else{
#    	my $outappend = $room-&gt;shell-&gt;command($command);
    	my $outappend = "<span class="command">$command</span>
" . $room-&gt;shell-&gt;command($command);
		$room-&gt;append($outappend);
	}
}

sub close{
	my $room = shift;
	$room-&gt;shell-&gt;close;
	# tell each controller in the room to leave the room (reset roomname attribute, remove self from room-&gt;controllers, update GUI
	foreach my $self ( $room-&gt;controllers-&gt;array ){ $self-&gt;leave_room }
	delete $nametoroom{ $room-&gt;name }; # delete the room from the nametoroom hash
}

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package room;

use strict; use warnings;

use feature 'switch';

use helpers;

use set;

use shell;

######################################### GLOBALS ########################################

our %nametoroom = ();

#################################### HELPER FUNCTIONS ####################################

our @namepool = ();

open( my $FH, '<', 'public/lexis.txt' ) or die 'Could not open the lexis!!!'; push @namepool => trim(lc $_) while( <$FH> ); # rooms are stored as lowercase, so the keys must be lc too!

close( $FH ) or die 'Could not CLOSE the lexis!';

sub rand_name{

my $randindex = int( $#namepool * rand() );

return $namepool[$randindex]

}

sub name_to_room{ # creates a new room if necessary

my ($name) = @_;

return $nametoroom{$name} //= room->new(name=>$name) or die 'Bad room name string!' # adds the room to our hash if necessary

}

sub htmlify{ # this takes any amount of terminal stdout and converts it to html.

my ( $str, $prompt ) = @_;

# put a span around the commands...

# $prompt = quotemeta $prompt;

# $str =~ s|^(.*)\n|$1\n|; # the very first command is NOT preceded by a prompt.

# $str =~ s|\n?$prompt(.*)\n|\n$1\n|g; # this also makes sure that prompts always start on new lines.

# $str =~ s|\n?$prompt$|\n|; # delete final prompt. Also, all endings have newlines regardless of what bash outputted.

# $str =~ s|\n$|\n\n|g; # for an outputless command, let's display an empty line to show that.

$str =~ s|\n|

|g;

return $str

}

######################################## NEW ROOM ########################################

sub new{

my $packagename = shift;

my %options = @_; # includes the NAME of the room.

my $room = bless {

name => $options{name},

shell => undef,

controllers => set->new,

output => '',

}

=> $packagename;

$room->shell('sh');

return $room

}

########################################## ROOM ##########################################

sub name{

my $room = shift;

return $room{name}

}

sub shell{

my $room = shift;

my ($shellname) = @_;

if( defined $shellname ){

$room->shell->close if defined $room->shell;

$room{shell} = shell->new( $shellname, $room );

my $divider = "\n###############################################################\n";

$room->append($divider."Welcome to a new $shellname shell!\n\n");

}

return $room{shell}

}

sub controllers{ # this is a SET of controllers

my $room = shift;

return $room{controllers}

}

sub add_controller{

my $room = shift;

my ($controller) = @_;

$room->controllers->add_element($controller)

}

sub remove_controller{ say 'removing a controller...';

my $room = shift;

my ($controller) = @_;

$room->controllers->remove_element($controller);

# check if the room is empty. if so, close the room.

if( $room->controllers->is_empty ){ say 'closing the room...'; $room->close }

}

sub output{ # gets all the output of a room for a new self joining in

my $room = shift;

return $room{output}

}

sub append_to_output{

my $room = shift;

my ($string) = @_;

$room{output} .= $string;

}

sub append{

my $room = shift;

my ($string) = @_;

$room->append_to_output($string);

# my $html = htmlify( $string, $room->shell->prompt );

my $html = htmlify( $string );

$room->jblast( command=>'append', output=>$html );

#say "output is now $room{output}";

}

sub jblast{ # blast is replaced with jblast, which includes the json in it

my $room = shift;

#say 'jblasting to '.scalar $room->controllers->array.' controllers.';

my %ball = @_; say 'ball is '."@_";

foreach( $room->controllers->array ){ #say 'i have a controller '."$_";

$_->jsend(%ball)

}

#say 'done WITH CONTROLLERS';

}

use overload

'""' => \&stringify;

sub stringify{

my $room = shift;

my $toprint;

{

local $" = ',';

$toprint .= 'Roomname is '.$room->name."\n";

my @controllers = $room->controllers->array; $toprint .= "Controllers are: @controllers\n";

}

return $toprint

}

sub command{ # executes a shell command and relays the output to all controllers.

my $room = shift;

my ($command) = @_; # incoming command does not have a \n at the end.

say "command is $command"; #say "Bin is $Bin";

if( $command =~ /^(shell) +([^ ]*)/i ){ # capture special room commands: shells

my $keyword = $1;

my $argument = lc trim $2;

given($keyword){

when('shell'){ # the argument has already been verified in $self->command

$room->shell($argument);

$room->jblast( command=>'set', id=>'shellname', html=>$argument, color=>"#f12772" );

}

else{

# my $outappend = $room->shell->command($command);

my $outappend = "$command

" . $room->shell->command($command);

$room->append($outappend);

}

sub close{

my $room = shift;

$room->shell->close;

# tell each controller in the room to leave the room (reset roomname attribute, remove self from room->controllers, update GUI

foreach my $self ( $room->controllers->array ){ $self->leave_room }

delete $nametoroom{ $room->name }; # delete the room from the nametoroom hash

}

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