NAME
IO::EventMux - Multiplexer for sockets, pipes and any other types of
filehandles that you can set O_NONBLOCK on and does buffering for the
user.
SYNOPSIS
use IO::EventMux;
my $mux = IO::EventMux->new();
$mux->add($my_fh, Listen => 1);
while (1) {
my $event = $mux->mux();
# ... do something with $event->{type} and $event->{fh}
}
DESCRIPTION
This module provides multiplexing for any set of sockets, pipes, or
whatever you can set O_NONBLOCK on. It can be useful for both server and
client processes, but it works best when the application's main loop is
centered around its "mux()" method.
The file handles it can work with are either perl's own typeglobs or
IO::Handle objects (preferred).
METHODS
new([%options])
Constructs an IO::EventMux object.
EventMux implements different types of priority queues that determined
how events are returned or written.
ReadPriorityType
The ReadPriorityType defines how reads should be return with the mux
call and how "fair" it should be. There is currently only 2
ReadPriorityTypes types to select from and using the default is
recommended.
The default is 'FairByEvent'.
FairByEvent
File handles change turn generating events and gets the minimum of
number of reads for generating one event, but if the data returned can
be used to generate more events. All events will be pushed to the
queue to be returned with the "mux()" call.
my $mux = IO::EventMux->new( ReadPriorityType => ['FairByEvent'] );
or
my $mux = IO::EventMux->new( ReadPriorityType => ['FairByEvent',
$reads_pr_turn] );
$reads_pr_turn is the number of reads the file handle gets to generate
an event.
Default $reads_pr_turn is 10. -1 for unlimited.
None
Events are generated based on the order the file handles are read,
this will allow file handles returning allot of events to monopolize
the event loop. This also allow the other end of the file handle to
fill the memory of the host as EventMux will continue reading so long
there is data on the file handle.
my $mux = IO::EventMux->new( ReadPriorityType => ['None'] );
Use this ReadPriorityType with care and only on trusted sources as
it's very easy to exploit.
mux([$timeout])
This method will block until ether an event occurs on one of the file
handles or the $timeout (floating point seconds) expires. If the
$timeout argument is not present, it waits forever. If $timeout is 0, it
returns immediately.
The return value is always a hash, which always has the key 'type',
indicating what kind it is. It will also usually carry the 'fh' key,
indicating what file handle the event happened on.
The 'type' key can have the following values:
timeout
Nothing happened and timeout occurred.
error
The "select()" system call failed. The event hash will have the key
'error', which is set to the value of $! at the time of the error.
Use kill() on the file handle to make the error be handled like a
normal "closed" event.
accepted
A new client connected to a listening socket and the connection was
accepted by EventMux. The listening socket file handle is in the
'parent_fh' key.
ready
A file handle is ready to be written to, this can be use full when
working with nonblocking connects so you know when the remote
connection accepted the connection.
accepting
A new client is trying to connect to a listening socket, but the
user code must call accept manually. This only happens when the
ManualAccept option is set.
read
A socket has incoming data. If the socket's Buffered option is set,
this will be what the buffering rule define.
The data is contained in the 'data' key of the event hash. If recv()
returned a sender address, it is contained in the 'sender' key and
must be manually unpacked according to the socket domain, e.g. with
"Socket::unpack_sockaddr_in()".
read_last
A socket last data before it was closed did not match the buffering
rules, this can happen with the following buffering types: Size,
FixedSize and Regexp. And is generally an indicator that you
received data that you did not expect.
The Buffering types: "Split", "Disconnect" and "None" expects this
and will return a read instead.
The default is not to return read_last, in the sense that "None" is
the default buffering type.
sent
A socket has sent all the data in it's queue with the send call.
This however does not indicate that the data has reached the other
end, normally only that the data has reached the local buffer of the
kernel.
closing
A file handle was detected to be have been closed by the other end
or the file handle was set to be closed by the user. So EventMux
stooped listening for events on this file handle. Event data like
'Meta' is still accessible.
The 'missing' key indicates the amount of data or packets left in
the user space buffer when the file handle was closed. This does not
indicate the amount of data received by the other end, only that the
user space buffer left.
closed
A socket/pipe was disconnected/closed, the file descriptor, all
internal references, and data store with the file handle was
removed.
can_write
The ManualWrite option is set for the file handle, and "select()"
has indicated that the handle can be written to.
can_read
The ManualRead option is set for the file handle, and "select()" has
indicated that the handle can be read from.
add($handle, [ %options ])
Add a socket to the internal list of handles being watched.
The optional parameters for the handle will be taken from the
IO::EventMux object if not given here:
Listen
Defines if this is should be treated as a listening socket, the default
is no.
The socket must be set up for listening, which is easily done with
IO::Socket::INET:
my $listener = IO::Socket::INET->new(
Listen => 5,
LocalPort => 7007,
ReuseAddr => 1,
);
$mux->add($listener, Listen => 1);
Type
Either "stream" or "dgram". Should be auto detected in most cases.
Defaults to "stream".
ManualAccept
If a connection comes in on a listening socket, it will by default be
accepted automatically, and mux() will return a 'connect' event. If
ManualAccept is set an 'accept' event will be returned instead, and the
user code must handle it itself.
$mux->add($my_fh, ManualAccept => 1);
ManualWrite
By default EventMux handles nonblocking writing and you should use
$mux->send($fh, $data) or $mux->sendto($fh, $addr, $data) to send your
data, but if some reason you send data yourself you can tell EventMux
not to do writing for you and generate a 'can_write' event for you
instead.
$mux->add($my_fh, ManualWrite => 1);
In both cases you can use send() to write data to the file handle.
Note: If both ManualRead and ManualWrite is set, EventMux will not set
the socket to nonblocking.
ManualRead
By default EventMux will handle nonblocking reading and generate a read
event with the data, but if some reason you would like to do the reading
yourself you can have EventMux generate a 'can_read' event for you
instead.
$mux->add($my_fh, ManualRead => 1);
Never read or recv on the file handle. When the socket becomes readable,
a "can_read" event is returned.
Note: If both ManualRead and ManualWrite is set, EventMux will not set
the socket to nonblocking.
ReadSize
By default EventMux will try to read 65536 bytes from the file handle,
setting this options to something smaller might help make it easier for
EventMux to be fair about how it returns it's event, but will also give
more overhead as more system calls will be required to empty a file
handle.
Buffered
Can be a number of different buffering types, common for all of them is
that they define when a event should be generated based on when there is
enough data for the buffering type to be satisfied. All buffering types
also generate an event with the remaining data when there is a
disconnect.
As a protection against a hostile remote end filling your memory a
$max_read_size is defined for most of buffering types, this defines the
maximum amount of data to read from a file handle before generating an
event.
The default buffering type is 'None'
Size
Buffering that reads the size from the data to determine when to
generate an event. Only the data is returned not the bytes that hold
the length information.
$mux->add($my_fh, Buffered => ['Size', $template]);
$template is a pack TEMPLATE, an event is returned when length defined
in the $template is reached.
$mux->add($my_fh, Buffered => ['Size', $template, $offset]);
$offset is the numbers of bytes to add to the length that was unpacked
with the $template.
$mux->add($my_fh, Buffered => ['Size', $template, $offset, $max_read_size]);
$max_read_size is the maximum number of bytes to read from the file
handle pr. event. The default is 1048576 bytes.
If the size read from the template is bigger than $max_read_size an
error event will be generated and only $max_read_size will be read
from the socket.
FixedSize
Buffering that uses a fixed size to determine when to generate an
event.
$mux->add($my_fh, Buffered => ['FixedSize', $size]);
$size is the number of bytes to buffer.
Split
Buffering that uses a regular expressing to determine where to split
data into events. Only the data is returned not the splitter pattern
itself.
$mux->add($my_fh, Buffered => ['Split', $regexp]);
or
$mux->add($my_fh, Buffered => ['Split', $regexp, $max_read_size]);
$regexp is a regular expressing that tells where the split the data.
This also works as line buffering when qr/\n/ is used or for a C
string with qr/\0/.
$max_read_size is the maximum number of bytes to read from the file
handle pr. event. The default is 1048576 bytes.
If no match has been reach after matching $max_read_size of data from
the buffer a error event will be generated and the $max_read_size of
data will be returned in a data event.
Regexp
Buffering that uses a regular expressing to determine when there is
enough data for an event. Only the match defined in the () is returned
not the complete regular expressing.
$mux->add($my_fh, Buffered => ['Regexp', $regexp]);
or
$mux->add($my_fh, Buffered => ['Regexp', $regexp, $max_read_size]);
$regexp is a regular expressing that tells what data to return.
An example would be qr/^(.+)\n/ that would work as line buffing.
$max_read_size is the maximum number of bytes to read from the file
handle pr. event. The default is 1048576 bytes.
If no match has been reach after matching $max_read_size of data from
the buffer a error event will be generated and the $max_read_size of
data will be returned in a data event.
Disconnect
Buffering that waits for the file handle to be closed or disconnected
to generate a 'read' event.
$mux->add($my_fh, Buffered => ['Disconnect']);
or
$mux->add($my_fh, Buffered => ['Disconnect', $max_read_size]);
$max_read_size is the maximum number of bytes to read from the file
handle pr. event. The default is 1048576 bytes.
If more data than $max_read_size if received before the file handle is
closed or disconnected, an error event will be generated and
$max_read_size of data will be returned in a data event.
None
Disable Buffering and return data when it's received. This is the
default state.
$mux->add($my_fh, Buffered => ['None']);
or
$mux->add($my_fh, Buffered => ['None', $max_read_size]);
$max_read_size is the maximum number of bytes to read from the file
handle pr. event. The default is 1048576 bytes.
Meta
An optional scalar piece of metadata for the file handle. Can be
retrieved and manipulated later with meta()
handles()
Returns a list of file handles managed by this object.
type()
Returns the socket type for a file handle
class()
Returns the socket class for a file handle
meta($fh, [$newval])
Set or get a piece of metadata on the filehandle. This can be any scalar
value.
remove($fh)
Make EventMux forget about a file handle. The caller will then take over
the responsibility of closing it.
close($fh)
Close a file handle. File handles managed by EventMux must be closed
through this method to make sure all resources are freed.
IO::EventMux will delay closing the file handle until the out buffer is
empty and at the same time stop listening on read event on that socket.
This in turn will also generate a 'closing' and a 'closed' event.
Note: All meta data associated with the file handle will be kept until
the final 'closed' event is returned.
kill($fh)
Closes a file handle without giving time to finish any outstanding
operations. Returns a 'closed' event, delete all buffers and does not
keep 'Meta' data.
Note: Does not return the 'read_last' event.
timeout($fh, [ $set_timeout ])
Get or set the read timeout for this file handle in seconds. When no
data has been received for this many seconds, a 'timeout' event will be
returned for this file handle.
Set the undefined value for infinite timeout, which is the default.
The timeout is reset to infinity if any data is read from the file
handle, so it should be set again before the next read if desired.
buflen($fh)
Queries the length of the output buffer for this file handle. This only
applies if ManualWrite is turned off, which is the default. For
Type="dgram" sockets, it returns the number of datagrams in the queue.
An application can use this method to see whether it should send more
data or wait until the buffer queue is a bit shorter.
send($fh, @data)
Queues @data to be written to the file handle $fh. Can only be used when
ManualWrite is off (default).
If the socket is of Type="stream"
Returns true on success, undef on error. The data is sent when the
socket becomes unblocked and a 'sent' event is posted when all data
is sent and the buffer is empty. Therefore the socket should not be
closed until "buflen($fh)" returns 0 or a sent request has been
posted.
If the socket is of Type="dgram"
Each item in @data will be sent as a separate packet. Returns true
on success and undef on error.
sendto($fh, $to, @data)
Like "send()", but with the recepient $to as a packed sockaddr
structure, such as the one returned by "Socket::pack_sockaddr_in()".
Only for Type="dgram" sockets.
$mux->sendto($my_fh, pack_sockaddr_in($port, inet_aton($ip)), $data);
push_event($event)
Puts socket into nonblocking mode.
nonblock($socket)
Puts socket into nonblocking mode.
AUTHOR
Jonas Jensen <jonas@infopro.dk>, Troels Liebe Bentsen
<troels@infopro.dk>
COPYRIGHT AND LICENCE
Copyright 2006-2007: Troels Liebe Bentsen, Jonas Jensen
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.