NAME
IO::Event - Tied Filehandles for Nonblocking IO with Object Callbacks
DESCRIPTION
IO::Event provides a object-based callback system for handling
nonblocking IO. The design goal is to provide a system that just does
the right thing w/o the user needing to think about it much.
All APIs are kept as simple as possible yet at the same time, all
functionality is accesible if needed. Simple things are easy. Hard
things are possible.
CONSTRUCTORS
IO::Event->new($filehandle, $handler)
The basic "new" constructor takes a filehandle and returns a
psuedo-filehandle. Treat the IO::Event object as a filehandle. Do
not use the original filehandle without good reason (let us know if
you find a good reason so we can fix the problem).
The handler is the class or object where you provide callback
functions to handle IO events. It defaults to the package of the
calling context.
IO::Event::Socket::INET->new( [ARGS] )
This constructor uses IO::Socket::INET->new() to create a socket
using the ARGS provided. It returns an IO::Event object.
The handler defaults as above or can be set with an additional
pseudo-parameter for IO::Socket::UNIX->new(): "Handler". A
description for the socket can be provided with an additional
psuedo-parameter: "Description".
IO::Event::Socket::UNIX->new( [ARGS] )
This constructor uses IO::Socket::UNIX->new() to create a socket
using the ARGS provided. It returns an IO::Event object.
The handler defaults as above or can be set with an additional
pseudo-parameter for IO::Socket::UNIX->new(): "Handler". A
description for the socket can be provided with an additional
psuedo-parameter: "Description".
MANDATORY HANDLERS
These handler methods must be available in the handler object/class if
thit situation in which they would be called arises.
ie_input($handler, $ieo, $input_buffer_reference)
Invoked when there is fresh data in the input buffer. The input can
be retreived via directly reading it from $$input_buffer_reference
or via "read()" from the $ieo filehandle, or by using a variety of
standard methods for getting data:
$ieo->get() like Data::LineBuffer
$ieo->read() like IO::Handle
$ieo->getline() like IO::Handle
$ieo->getlines() like IO::Handle
<$ieo> like IO::Handle
ie_connection($handler, $ieo)
Invoked when a listen()ing socket is ready to accept(). It should
call accept:
sub ie_connection
{
my ($ieo) = @_;
my $newfh = $ieo->accept()
}
ie_read_ready($handler, $underlying_file_handle)
If autoreading is turned off then this will be invoked.
OPTIONAL HANDLERS
These handler methods will be called if they are defined but it is not
required that they be defined.
ie_eof($handler, $ieo, $input_buffer_reference)
This is invoked when the read-side of the filehandle has been closed
by its source.
ie_output
This is invoked when data has just been written to the underlying
filehandle.
ie_outputdone
This is invoked when all pending data has just been written to the
underlying filehandle.
ie_connected
This is invoked when a "connect()" completes.
ie_connect_timeout
This is invoked when a "connect()" attempt times out.
ie_died($handler, $ieo, $method, $@)
If another handler calls "die" then ie_died will be called with the
IO::Event object, the name of the method just invoked, and the die
string.
ie_timer
This is invoked for timer events. These will only arise if set using
thing underlying Event object.
ie_exception
Invoked when an exceptional condition arises on the underlying
filehandle
METHODS
In addition to methods described in detail below, the following methods
behave like their "IO" (mostly "IO::Socket") counterparts (except for
being mostly non-blocking...):
connect
listen
open
close
read
syswrite
print
eof
Through AUTOLOAD (see the SUBSTITUTED METHODS section) methods are
passed to underlying "Event" objects:
loop
unloop
and many more...
Through AUTOLOAD (see the SUBSTITUTED METHODS section) methods are
passed to underlying "IO" objects:
fileno
stat
truncate
error
opened
untaint
and many more...
IO::Event defines its own methods too:
->accept($handler)
accept() is nearly identical to the normal IO::Socket::accpt()
method except that instead of optionally passing a class specifier
for the new socket, you optionally pass a handler object/class. The
returned filehandle is an IO::Event object.
->get()
get() is like getline() except that it pre-chomp()s the results and
assumes the input_record_separator is "\n". This is like get() from
Data::LineBuffer.
->unget()
Push chomp()ed lines back into the input buffer. This is like
unget() from Data::LineBuffer.
->ungetline()
Push un-chomp()ed lines back into the input buffer.
->handler($new_handler)
Sets the handler object/class if $new_handler is provided. Returns
the old handler.
->filehandle()
Returns the underlying "IO::Handle".
->event()
Returns the underling "Event".
->listener($listening)
Used to note that a filehandle is being used to listen for
connections (instead of receiving data). A passed parameter of 0
does the opposite. Returns the old value. This is mostly used
internally to IO::Event.
->autoread($autoread)
Get/set automatic reading if data when data can be read. Without
autoread turned on, the input buffer ins't filled and none of the
read methods will work. The point of this is for working with
non-data filehandles. This is an experts-only method that kinda
defeats the purpose of this module. This would be necessary using
recv() to get data.
->drain()
Used to start looking for write-ready events on the underlying
filehandle.
->input_record_separator($new_sep)
IO::Handle doesn't allow input_record_separator's on a per
filehandle basis. IO::Event does. If you don't ever set a
filehandle's input record separator, then it contineously defaults
to the current value of $/. If you set it, then it will use your
value and never look at $/ again.
SUBSTITUED METHODS
Any method invications that fail because the method isn't defined in
IO::Event will by tried twice more: once using trying for a method on
the inner (hidden) filehandle and once more trying the for a method on
the Event object that's used to create the select loop for this module.
EXAMPLE SERVER
# This is a tcp line echo server
my $listener = IO::Event::Socket::INET->new(
Listen => 10,
Proto => 'tcp',
LocalPort => 2821,
);
Event::loop();
sub ie_connection
{
my ($pkg, $lstnr) = @_;
my $client = $lstnr->accept();
printf "accepted connection from %s:%s\n",
$client->peerhost, $client->peerport;
}
sub ie_input
{
my ($pkg, $client, $ibufref) = @_;
print $client <$client>;
}
SEE ALSO
The following perl modules do something that is kinda similar to what is
being done here:
