# POE::Wheel::ListenAccept - phpMan ## NAME [POE::Wheel::ListenAccept] - accept connections from regular listening sockets ## SYNOPSIS See "SYNOPSIS" in [POE::Wheel::SocketFactory] for a simpler version of this program. #!perl use warnings; use strict; use [IO::Socket]; use POE qw([Wheel::ListenAccept] [Wheel::ReadWrite]); [POE::Session]->create( inline_states => { _start => sub { # Start the server. $_[HEAP]{server} = [POE::Wheel::ListenAccept]->new( Handle => [IO::Socket::INET]->new( LocalPort => 12345, Listen => 5, ), AcceptEvent => "on_client_accept", ErrorEvent => "on_server_error", ); }, on_client_accept => sub { # Begin interacting with the client. my $client_socket = $_[ARG0]; my $io_wheel = [POE::Wheel::ReadWrite]->new( Handle => $client_socket, InputEvent => "on_client_input", ErrorEvent => "on_client_error", ); $_[HEAP]{client}{ $io_wheel->ID() } = $io_wheel; }, on_server_error => sub { # Shut down server. my ($operation, $errnum, $errstr) = @_[ARG0, ARG1, ARG2]; warn "Server $operation error $errnum: $errstr\n"; delete $_[HEAP]{server}; }, on_client_input => sub { # Handle client input. my ($input, $wheel_id) = @_[ARG0, ARG1]; $input =~ tr[a-zA-Z][n-za-mN-ZA-M]; # ASCII rot13 $_[HEAP]{client}{$wheel_id}->put($input); }, on_client_error => sub { # Handle client error, including disconnect. my $wheel_id = $_[ARG3]; delete $_[HEAP]{client}{$wheel_id}; }, } ); [POE::Kernel]->run(); exit; ## DESCRIPTION [POE::Wheel::ListenAccept] implements non-blocking accept() calls for plain old listening server sockets. The application provides the socket, using some normal means such as socket(), [IO::Socket::INET], or [IO::Socket::UNIX]. [POE::Wheel::ListenAccept] monitors the listening socket and emits events whenever a new client has been accepted. Please see [POE::Wheel::SocketFactory] if you need non-blocking connect() or a more featureful listen/accept solution. [POE::Wheel::ListenAccept] only accepts client connections. It does not read or write data, so it neither needs nor includes a put() method. [POE::Wheel::ReadWrite] generally handles the accepted client socket. ## PUBLIC METHODS new new() creates a new [POE::Wheel::ListenAccept] object for a given listening socket. The object will generate events relating to the socket for as long as it exists. new() accepts two required named parameters: Handle The "Handle" constructor parameter must contain a listening socket handle. [POE::Wheel::FollowTail] will monitor this socket and accept() new connections as they arrive. AcceptEvent "AcceptEvent" is a required event name that [POE::Wheel::ListenAccept] will emit for each accepted client socket. "PUBLIC EVENTS" describes it in detail ErrorEvent "ErrorEvent" is an optional event name that will be emitted whenever a serious problem occurs. Please see "PUBLIC EVENTS" for more details. event event() allows a session to change the events emitted by a wheel without destroying and re-creating the object. It accepts one or more of the events listed in "PUBLIC EVENTS". Undefined event names disable those events. Ignore connections: sub ignore_new_connections { $_[HEAP]{tailor}->event( AcceptEvent => "on_ignored_accept" ); } sub handle_ignored_accept { # does nothing } ID The ID() method returns the wheel's unique ID. It's useful for storing the wheel in a hash. All [POE::Wheel] events should be accompanied by a wheel ID, which allows the wheel to be referenced in their event handlers. sub setup_listener { my $wheel = [POE::Wheel::ListenAccept]->new(... etc ...); $_[HEAP]{listeners}{$wheel->ID} = $wheel; } ## PUBLIC EVENTS [POE::Wheel::ListenAccept] emits a couple events. AcceptEvent "AcceptEvent" names the event that will be emitted for each newly accepted client socket. It is accompanied by three parameters: $_[ARG0] contains the newly accepted client socket handle. It's up to the application to do something with this socket. Most use cases involve passing the socket to a [POE::Wheel::ReadWrite] constructor. $_[ARG1] contains the accept() call's return value, which is often the encoded remote end of the remote end of the socket. $_[ARG2] contains the [POE::Wheel::ListenAccept] object's unique ID. This is the same value as returned by the wheel's ID() method. A sample "AcceptEvent" handler: sub accept_state { my ($client_socket, $remote_addr, $wheel_id) = @_[ARG0..ARG2]; # Make the remote address human readable. my ($port, $packed_ip) = sockaddr_in($remote_addr); my $dotted_quad = inet_ntoa($packed_ip); print( "Wheel $wheel_id accepted a connection from ", "$dotted_quad port $port.\n" ); # Spawn off a session to interact with the socket. create_server_session($handle); } ErrorEvent "ErrorEvent" names the event that will be generated whenever a new connection could not be successfully accepted. This event is accompanied by four parameters: $_[ARG0] contains the name of the operation that failed. This usually is 'accept', but be aware that it's not necessarily a function name. $_[ARG1] and $_[ARG2] hold the numeric and stringified values of $!, respectively. [POE::Wheel::ListenAccept] knows how to handle EAGAIN (and system-dependent equivalents), so this error will never be returned. $_[ARG3] contains the wheel's unique ID, which may be useful for shutting down one particular wheel out of a group of them. A sample "ErrorEvent" event handler. This assumes the wheels are saved as in the "ID" example. sub error_state { my ($operation, $errnum, $errstr, $wheel_id) = @_[ARG0..ARG3]; warn "Wheel $wheel_id generated $operation error $errnum: $errstr\n"; delete $_[HEAP]{listeners}{$wheel_id}; } ## SEE ALSO [POE::Wheel] describes the basic operations of all wheels in more depth. You need to know this. [POE::Wheel::ReadWrite] for one possible way to handle clients once you have their sockets. The SEE ALSO section in POE contains a table of contents covering the entire POE distribution. ## BUGS None known. AUTHORS & COPYRIGHTS Please see POE for more information about authors and contributors.