ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/AnyEvent/lib/AnyEvent/Handle.pm

Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.5 by elmex, Mon Apr 28 08:01:05 2008 UTC vs.
Revision 1.159 by root, Fri Jul 24 12:35:58 2009 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	use warnings;	3	use Scalar::Util ();
4	use strict;	4	use Carp ();
5
6	use AnyEvent;
7	use IO::Handle;
8	use Errno qw/EAGAIN EINTR/;	5	use Errno qw(EAGAIN EINTR);
		6
		7	use AnyEvent (); BEGIN { AnyEvent::common_sense }
		8	use AnyEvent::Util qw(WSAEWOULDBLOCK);
9		9
10	=head1 NAME	10	=head1 NAME
11		11
12	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	12	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
13		13
14	=head1 VERSION
15
16	Version 0.01
17
18	=cut	14	=cut
19		15
20	our $VERSION = '0.01';	16	our $VERSION = 4.86;
21		17
22	=head1 SYNOPSIS	18	=head1 SYNOPSIS
23		19
24	use AnyEvent;	20	use AnyEvent;
25	use AnyEvent::Handle;	21	use AnyEvent::Handle;
26		22
27	my $cv = AnyEvent->condvar;	23	my $cv = AnyEvent->condvar;
28		24
29	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	25	my $hdl; $hdl = new AnyEvent::Handle
		26	fh => \*STDIN,
		27	on_error => sub {
		28	my ($hdl, $fatal, $msg) = @_;
		29	warn "got error $msg\n";
		30	$hdl->destroy;
		31	$cv->send;
		32	);
30		33
31	$ae_fh->on_eof (sub { $cv->broadcast });	34	# send some request line
		35	$hdl->push_write ("getinfo\015\012");
32		36
33	$ae_fh->readlines (sub {	37	# read the response line
		38	$hdl->push_read (line => sub {
34	my ($ae_fh, @lines) = @_;	39	my ($hdl, $line) = @_;
35	for (@lines) {	40	warn "got line <$line>\n";
36	chomp;	41	$cv->send;
37	print "Line: $_";	42	});
		43
		44	$cv->recv;
		45
		46	=head1 DESCRIPTION
		47
		48	This module is a helper module to make it easier to do event-based I/O on
		49	filehandles.
		50
		51	The L<AnyEvent::Intro> tutorial contains some well-documented
		52	AnyEvent::Handle examples.
		53
		54	In the following, when the documentation refers to of "bytes" then this
		55	means characters. As sysread and syswrite are used for all I/O, their
		56	treatment of characters applies to this module as well.
		57
		58	At the very minimum, you should specify C<fh> or C<connect>, and the
		59	C<on_error> callback.
		60
		61	All callbacks will be invoked with the handle object as their first
		62	argument.
		63
		64	=head1 METHODS
		65
		66	=over 4
		67
		68	=item $handle = B<new> AnyEvent::TLS fh => $filehandle, key => value...
		69
		70	The constructor supports these arguments (all as C<< key => value >> pairs).
		71
		72	=over 4
		73
		74	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
		75
		76	The filehandle this L<AnyEvent::Handle> object will operate on.
		77	NOTE: The filehandle will be set to non-blocking mode (using
		78	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		79	that mode.
		80
		81	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
		82
		83	Try to connect to the specified host and service (port), using
		84	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		85	default C<peername>.
		86
		87	You have to specify either this parameter, or C<fh>, above.
		88
		89	When this parameter is specified, then the C<on_prepare>,
		90	C<on_connect_error> and C<on_connect> callbacks will be called under the
		91	appropriate circumstances:
		92
		93	=over 4
		94
		95	=item on_prepare => $cb->($handle)
		96
		97	This (rarely used) callback is called before a new connection is
		98	attempted, but after the file handle has been created. It could be used to
		99	prepare the file handle with parameters required for the actual connect
		100	(as opposed to settings that can be changed when the connection is already
		101	established).
		102
		103	=item on_connect => $cb->($handle, $host, $port, $retry->())
		104
		105	This callback is called when a connection has been successfully established.
		106
		107	The actual numeric host and port (the socket peername) are passed as
		108	parameters, together with a retry callback.
		109
		110	When, for some reason, the handle is not acceptable, then calling
		111	C<$retry> will continue with the next conenction target (in case of
		112	multi-homed hosts or SRV records there can be multiple connection
		113	endpoints). When it is called then the read and write queues, eof status,
		114	tls status and similar properties of the handle are being reset.
		115
		116	In most cases, ignoring the C<$retry> parameter is the way to go.
		117
		118	=item on_connect_error => $cb->($handle, $message)
		119
		120	This callback is called when the conenction could not be
		121	established. C<$!> will contain the relevant error code, and C<$message> a
		122	message describing it (usually the same as C<"$!">).
		123
		124	If this callback isn't specified, then C<on_error> will be called with a
		125	fatal error instead.
		126
		127	=back
		128
		129	=item on_error => $cb->($handle, $fatal, $message)
		130
		131	This is the error callback, which is called when, well, some error
		132	occured, such as not being able to resolve the hostname, failure to
		133	connect or a read error.
		134
		135	Some errors are fatal (which is indicated by C<$fatal> being true). On
		136	fatal errors the handle object will be destroyed (by a call to C<< ->
		137	destroy >>) after invoking the error callback (which means you are free to
		138	examine the handle object). Examples of fatal errors are an EOF condition
		139	with active (but unsatisifable) read watchers (C<EPIPE>) or I/O errors. In
		140	cases where the other side can close the connection at their will it is
		141	often easiest to not report C<EPIPE> errors in this callback.
		142
		143	AnyEvent::Handle tries to find an appropriate error code for you to check
		144	against, but in some cases (TLS errors), this does not work well. It is
		145	recommended to always output the C<$message> argument in human-readable
		146	error messages (it's usually the same as C<"$!">).
		147
		148	Non-fatal errors can be retried by simply returning, but it is recommended
		149	to simply ignore this parameter and instead abondon the handle object
		150	when this callback is invoked. Examples of non-fatal errors are timeouts
		151	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		152
		153	On callback entrance, the value of C<$!> contains the operating system
		154	error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		155	C<EPROTO>).
		156
		157	While not mandatory, it is I<highly> recommended to set this callback, as
		158	you will not be notified of errors otherwise. The default simply calls
		159	C<croak>.
		160
		161	=item on_read => $cb->($handle)
		162
		163	This sets the default read callback, which is called when data arrives
		164	and no read request is in the queue (unlike read queue callbacks, this
		165	callback will only be called when at least one octet of data is in the
		166	read buffer).
		167
		168	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
		169	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		170	must not enlarge or modify the read buffer, you can only remove data at
		171	the beginning from it.
		172
		173	When an EOF condition is detected then AnyEvent::Handle will first try to
		174	feed all the remaining data to the queued callbacks and C<on_read> before
		175	calling the C<on_eof> callback. If no progress can be made, then a fatal
		176	error will be raised (with C<$!> set to C<EPIPE>).
		177
		178	Note that, unlike requests in the read queue, an C<on_read> callback
		179	doesn't mean you I<require> some data: if there is an EOF and there
		180	are outstanding read requests then an error will be flagged. With an
		181	C<on_read> callback, the C<on_eof> callback will be invoked.
		182
		183	=item on_eof => $cb->($handle)
		184
		185	Set the callback to be called when an end-of-file condition is detected,
		186	i.e. in the case of a socket, when the other side has closed the
		187	connection cleanly, and there are no outstanding read requests in the
		188	queue (if there are read requests, then an EOF counts as an unexpected
		189	connection close and will be flagged as an error).
		190
		191	For sockets, this just means that the other side has stopped sending data,
		192	you can still try to write data, and, in fact, one can return from the EOF
		193	callback and continue writing data, as only the read part has been shut
		194	down.
		195
		196	If an EOF condition has been detected but no C<on_eof> callback has been
		197	set, then a fatal error will be raised with C<$!> set to <0>.
		198
		199	=item on_drain => $cb->($handle)
		200
		201	This sets the callback that is called when the write buffer becomes empty
		202	(or when the callback is set and the buffer is empty already).
		203
		204	To append to the write buffer, use the C<< ->push_write >> method.
		205
		206	This callback is useful when you don't want to put all of your write data
		207	into the queue at once, for example, when you want to write the contents
		208	of some file to the socket you might not want to read the whole file into
		209	memory and push it into the queue, but instead only read more data from
		210	the file when the write queue becomes empty.
		211
		212	=item timeout => $fractional_seconds
		213
		214	If non-zero, then this enables an "inactivity" timeout: whenever this many
		215	seconds pass without a successful read or write on the underlying file
		216	handle, the C<on_timeout> callback will be invoked (and if that one is
		217	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		218
		219	Note that timeout processing is also active when you currently do not have
		220	any outstanding read or write requests: If you plan to keep the connection
		221	idle then you should disable the timout temporarily or ignore the timeout
		222	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		223	restart the timeout.
		224
		225	Zero (the default) disables this timeout.
		226
		227	=item on_timeout => $cb->($handle)
		228
		229	Called whenever the inactivity timeout passes. If you return from this
		230	callback, then the timeout will be reset as if some activity had happened,
		231	so this condition is not fatal in any way.
		232
		233	=item rbuf_max => <bytes>
		234
		235	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		236	when the read buffer ever (strictly) exceeds this size. This is useful to
		237	avoid some forms of denial-of-service attacks.
		238
		239	For example, a server accepting connections from untrusted sources should
		240	be configured to accept only so-and-so much data that it cannot act on
		241	(for example, when expecting a line, an attacker could send an unlimited
		242	amount of data without a callback ever being called as long as the line
		243	isn't finished).
		244
		245	=item autocork => <boolean>
		246
		247	When disabled (the default), then C<push_write> will try to immediately
		248	write the data to the handle, if possible. This avoids having to register
		249	a write watcher and wait for the next event loop iteration, but can
		250	be inefficient if you write multiple small chunks (on the wire, this
		251	disadvantage is usually avoided by your kernel's nagle algorithm, see
		252	C<no_delay>, but this option can save costly syscalls).
		253
		254	When enabled, then writes will always be queued till the next event loop
		255	iteration. This is efficient when you do many small writes per iteration,
		256	but less efficient when you do a single write only per iteration (or when
		257	the write buffer often is full). It also increases write latency.
		258
		259	=item no_delay => <boolean>
		260
		261	When doing small writes on sockets, your operating system kernel might
		262	wait a bit for more data before actually sending it out. This is called
		263	the Nagle algorithm, and usually it is beneficial.
		264
		265	In some situations you want as low a delay as possible, which can be
		266	accomplishd by setting this option to a true value.
		267
		268	The default is your opertaing system's default behaviour (most likely
		269	enabled), this option explicitly enables or disables it, if possible.
		270
		271	=item read_size => <bytes>
		272
		273	The default read block size (the amount of bytes this module will
		274	try to read during each loop iteration, which affects memory
		275	requirements). Default: C<8192>.
		276
		277	=item low_water_mark => <bytes>
		278
		279	Sets the amount of bytes (default: C<0>) that make up an "empty" write
		280	buffer: If the write reaches this size or gets even samller it is
		281	considered empty.
		282
		283	Sometimes it can be beneficial (for performance reasons) to add data to
		284	the write buffer before it is fully drained, but this is a rare case, as
		285	the operating system kernel usually buffers data as well, so the default
		286	is good in almost all cases.
		287
		288	=item linger => <seconds>
		289
		290	If non-zero (default: C<3600>), then the destructor of the
		291	AnyEvent::Handle object will check whether there is still outstanding
		292	write data and will install a watcher that will write this data to the
		293	socket. No errors will be reported (this mostly matches how the operating
		294	system treats outstanding data at socket close time).
		295
		296	This will not work for partial TLS data that could not be encoded
		297	yet. This data will be lost. Calling the C<stoptls> method in time might
		298	help.
		299
		300	=item peername => $string
		301
		302	A string used to identify the remote site - usually the DNS hostname
		303	(I<not> IDN!) used to create the connection, rarely the IP address.
		304
		305	Apart from being useful in error messages, this string is also used in TLS
		306	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		307	verification will be skipped when C<peername> is not specified or
		308	C<undef>.
		309
		310	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		311
		312	When this parameter is given, it enables TLS (SSL) mode, that means
		313	AnyEvent will start a TLS handshake as soon as the conenction has been
		314	established and will transparently encrypt/decrypt data afterwards.
		315
		316	All TLS protocol errors will be signalled as C<EPROTO>, with an
		317	appropriate error message.
		318
		319	TLS mode requires Net::SSLeay to be installed (it will be loaded
		320	automatically when you try to create a TLS handle): this module doesn't
		321	have a dependency on that module, so if your module requires it, you have
		322	to add the dependency yourself.
		323
		324	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		325	C<accept>, and for the TLS client side of a connection, use C<connect>
		326	mode.
		327
		328	You can also provide your own TLS connection object, but you have
		329	to make sure that you call either C<Net::SSLeay::set_connect_state>
		330	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		331	AnyEvent::Handle. Also, this module will take ownership of this connection
		332	object.
		333
		334	At some future point, AnyEvent::Handle might switch to another TLS
		335	implementation, then the option to use your own session object will go
		336	away.
		337
		338	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		339	passing in the wrong integer will lead to certain crash. This most often
		340	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		341	segmentation fault.
		342
		343	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		344
		345	=item tls_ctx => $anyevent_tls
		346
		347	Use the given C<AnyEvent::TLS> object to create the new TLS connection
		348	(unless a connection object was specified directly). If this parameter is
		349	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		350
		351	Instead of an object, you can also specify a hash reference with C<< key
		352	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		353	new TLS context object.
		354
		355	=item on_starttls => $cb->($handle, $success[, $error_message])
		356
		357	This callback will be invoked when the TLS/SSL handshake has finished. If
		358	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		359	(C<on_stoptls> will not be called in this case).
		360
		361	The session in C<< $handle->{tls} >> can still be examined in this
		362	callback, even when the handshake was not successful.
		363
		364	TLS handshake failures will not cause C<on_error> to be invoked when this
		365	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		366
		367	Without this callback, handshake failures lead to C<on_error> being
		368	called, as normal.
		369
		370	Note that you cannot call C<starttls> right again in this callback. If you
		371	need to do that, start an zero-second timer instead whose callback can
		372	then call C<< ->starttls >> again.
		373
		374	=item on_stoptls => $cb->($handle)
		375
		376	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		377	set, then it will be invoked after freeing the TLS session. If it is not,
		378	then a TLS shutdown condition will be treated like a normal EOF condition
		379	on the handle.
		380
		381	The session in C<< $handle->{tls} >> can still be examined in this
		382	callback.
		383
		384	This callback will only be called on TLS shutdowns, not when the
		385	underlying handle signals EOF.
		386
		387	=item json => JSON or JSON::XS object
		388
		389	This is the json coder object used by the C<json> read and write types.
		390
		391	If you don't supply it, then AnyEvent::Handle will create and use a
		392	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		393	texts.
		394
		395	Note that you are responsible to depend on the JSON module if you want to
		396	use this functionality, as AnyEvent does not have a dependency itself.
		397
		398	=back
		399
		400	=cut
		401
		402	sub new {
		403	my $class = shift;
		404	my $self = bless { @_ }, $class;
		405
		406	if ($self->{fh}) {
		407	$self->_start;
		408	return unless $self->{fh}; # could be gone by now
		409
		410	} elsif ($self->{connect}) {
		411	require AnyEvent::Socket;
		412
		413	$self->{peername} = $self->{connect}[0]
		414	unless exists $self->{peername};
		415
		416	$self->{_skip_drain_rbuf} = 1;
		417
		418	{
		419	Scalar::Util::weaken (my $self = $self);
		420
		421	$self->{_connect} =
		422	AnyEvent::Socket::tcp_connect (
		423	$self->{connect}[0],
		424	$self->{connect}[1],
		425	sub {
		426	my ($fh, $host, $port, $retry) = @_;
		427
		428	if ($fh) {
		429	$self->{fh} = $fh;
		430
		431	delete $self->{_skip_drain_rbuf};
		432	$self->_start;
		433
		434	$self->{on_connect}
		435	and $self->{on_connect}($self, $host, $port, sub {
		436	delete @$self{qw(fh _tw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		437	$self->{_skip_drain_rbuf} = 1;
		438	&$retry;
		439	});
		440
		441	} else {
		442	if ($self->{on_connect_error}) {
		443	$self->{on_connect_error}($self, "$!");
		444	$self->destroy;
		445	} else {
		446	$self->fatal ($!, 1);
		447	}
		448	}
		449	},
		450	sub {
		451	local $self->{fh} = $_[0];
		452
		453	$self->{on_prepare}->($self)
		454	if $self->{on_prepare};
		455	}
		456	);
		457	}
		458
		459	} else {
		460	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		461	}
		462
		463	$self
		464	}
		465
		466	sub _start {
		467	my ($self) = @_;
		468
		469	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		470
		471	$self->{_activity} = AnyEvent->now;
		472	$self->_timeout;
		473
		474	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		475
		476	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		477	if $self->{tls};
		478
		479	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};
		480
		481	$self->start_read
		482	if $self->{on_read} || @{ $self->{_queue} };
		483	}
		484
		485	#sub _shutdown {
		486	# my ($self) = @_;
		487	#
		488	# delete @$self{qw(_tw _rw _ww fh wbuf on_read _queue)};
		489	# $self->{_eof} = 1; # tell starttls et. al to stop trying
		490	#
		491	# &_freetls;
		492	#}
		493
		494	sub _error {
		495	my ($self, $errno, $fatal, $message) = @_;
		496
		497	$! = $errno;
		498	$message ||= "$!";
		499
		500	if ($self->{on_error}) {
		501	$self->{on_error}($self, $fatal, $message);
		502	$self->destroy if $fatal;
		503	} elsif ($self->{fh}) {
		504	$self->destroy;
		505	Carp::croak "AnyEvent::Handle uncaught error: $message";
		506	}
		507	}
		508
		509	=item $fh = $handle->fh
		510
		511	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		512
		513	=cut
		514
		515	sub fh { $_[0]{fh} }
		516
		517	=item $handle->on_error ($cb)
		518
		519	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		520
		521	=cut
		522
		523	sub on_error {
		524	$_[0]{on_error} = $_[1];
		525	}
		526
		527	=item $handle->on_eof ($cb)
		528
		529	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		530
		531	=cut
		532
		533	sub on_eof {
		534	$_[0]{on_eof} = $_[1];
		535	}
		536
		537	=item $handle->on_timeout ($cb)
		538
		539	Replace the current C<on_timeout> callback, or disables the callback (but
		540	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		541	argument and method.
		542
		543	=cut
		544
		545	sub on_timeout {
		546	$_[0]{on_timeout} = $_[1];
		547	}
		548
		549	=item $handle->autocork ($boolean)
		550
		551	Enables or disables the current autocork behaviour (see C<autocork>
		552	constructor argument). Changes will only take effect on the next write.
		553
		554	=cut
		555
		556	sub autocork {
		557	$_[0]{autocork} = $_[1];
		558	}
		559
		560	=item $handle->no_delay ($boolean)
		561
		562	Enables or disables the C<no_delay> setting (see constructor argument of
		563	the same name for details).
		564
		565	=cut
		566
		567	sub no_delay {
		568	$_[0]{no_delay} = $_[1];
		569
		570	eval {
		571	local $SIG{__DIE__};
		572	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1]
		573	if $_[0]{fh};
		574	};
		575	}
		576
		577	=item $handle->on_starttls ($cb)
		578
		579	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		580
		581	=cut
		582
		583	sub on_starttls {
		584	$_[0]{on_starttls} = $_[1];
		585	}
		586
		587	=item $handle->on_stoptls ($cb)
		588
		589	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		590
		591	=cut
		592
		593	sub on_starttls {
		594	$_[0]{on_stoptls} = $_[1];
		595	}
		596
		597	#############################################################################
		598
		599	=item $handle->timeout ($seconds)
		600
		601	Configures (or disables) the inactivity timeout.
		602
		603	=cut
		604
		605	sub timeout {
		606	my ($self, $timeout) = @_;
		607
		608	$self->{timeout} = $timeout;
		609	$self->_timeout;
		610	}
		611
		612	# reset the timeout watcher, as neccessary
		613	# also check for time-outs
		614	sub _timeout {
		615	my ($self) = @_;
		616
		617	if ($self->{timeout} && $self->{fh}) {
		618	my $NOW = AnyEvent->now;
		619
		620	# when would the timeout trigger?
		621	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		622
		623	# now or in the past already?
		624	if ($after <= 0) {
		625	$self->{_activity} = $NOW;
		626
		627	if ($self->{on_timeout}) {
		628	$self->{on_timeout}($self);
		629	} else {
		630	$self->_error (Errno::ETIMEDOUT);
		631	}
		632
		633	# callback could have changed timeout value, optimise
		634	return unless $self->{timeout};
		635
		636	# calculate new after
		637	$after = $self->{timeout};
		638	}
		639
		640	Scalar::Util::weaken $self;
		641	return unless $self; # ->error could have destroyed $self
		642
		643	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		644	delete $self->{_tw};
		645	$self->_timeout;
		646	});
		647	} else {
		648	delete $self->{_tw};
		649	}
		650	}
		651
		652	#############################################################################
		653
		654	=back
		655
		656	=head2 WRITE QUEUE
		657
		658	AnyEvent::Handle manages two queues per handle, one for writing and one
		659	for reading.
		660
		661	The write queue is very simple: you can add data to its end, and
		662	AnyEvent::Handle will automatically try to get rid of it for you.
		663
		664	When data could be written and the write buffer is shorter then the low
		665	water mark, the C<on_drain> callback will be invoked.
		666
		667	=over 4
		668
		669	=item $handle->on_drain ($cb)
		670
		671	Sets the C<on_drain> callback or clears it (see the description of
		672	C<on_drain> in the constructor).
		673
		674	=cut
		675
		676	sub on_drain {
		677	my ($self, $cb) = @_;
		678
		679	$self->{on_drain} = $cb;
		680
		681	$cb->($self)
		682	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		683	}
		684
		685	=item $handle->push_write ($data)
		686
		687	Queues the given scalar to be written. You can push as much data as you
		688	want (only limited by the available memory), as C<AnyEvent::Handle>
		689	buffers it independently of the kernel.
		690
		691	=cut
		692
		693	sub _drain_wbuf {
		694	my ($self) = @_;
		695
		696	if (!$self->{_ww} && length $self->{wbuf}) {
		697
		698	Scalar::Util::weaken $self;
		699
		700	my $cb = sub {
		701	my $len = syswrite $self->{fh}, $self->{wbuf};
		702
		703	if (defined $len) {
		704	substr $self->{wbuf}, 0, $len, "";
		705
		706	$self->{_activity} = AnyEvent->now;
		707
		708	$self->{on_drain}($self)
		709	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		710	&& $self->{on_drain};
		711
		712	delete $self->{_ww} unless length $self->{wbuf};
		713	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		714	$self->_error ($!, 1);
		715	}
		716	};
		717
		718	# try to write data immediately
		719	$cb->() unless $self->{autocork};
		720
		721	# if still data left in wbuf, we need to poll
		722	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		723	if length $self->{wbuf};
		724	};
		725	}
		726
		727	our %WH;
		728
		729	sub register_write_type($$) {
		730	$WH{$_[0]} = $_[1];
		731	}
		732
		733	sub push_write {
		734	my $self = shift;
		735
		736	if (@_ > 1) {
		737	my $type = shift;
		738
		739	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		740	->($self, @_);
		741	}
		742
		743	if ($self->{tls}) {
		744	$self->{_tls_wbuf} .= $_[0];
		745
		746	&_dotls ($self);
		747	} else {
		748	$self->{wbuf} .= $_[0];
		749	$self->_drain_wbuf if $self->{fh};
		750	}
		751	}
		752
		753	=item $handle->push_write (type => @args)
		754
		755	Instead of formatting your data yourself, you can also let this module do
		756	the job by specifying a type and type-specific arguments.
		757
		758	Predefined types are (if you have ideas for additional types, feel free to
		759	drop by and tell us):
		760
		761	=over 4
		762
		763	=item netstring => $string
		764
		765	Formats the given value as netstring
		766	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		767
		768	=cut
		769
		770	register_write_type netstring => sub {
		771	my ($self, $string) = @_;
		772
		773	(length $string) . ":$string,"
		774	};
		775
		776	=item packstring => $format, $data
		777
		778	An octet string prefixed with an encoded length. The encoding C<$format>
		779	uses the same format as a Perl C<pack> format, but must specify a single
		780	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		781	optional C<!>, C<< < >> or C<< > >> modifier).
		782
		783	=cut
		784
		785	register_write_type packstring => sub {
		786	my ($self, $format, $string) = @_;
		787
		788	pack "$format/a*", $string
		789	};
		790
		791	=item json => $array_or_hashref
		792
		793	Encodes the given hash or array reference into a JSON object. Unless you
		794	provide your own JSON object, this means it will be encoded to JSON text
		795	in UTF-8.
		796
		797	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		798	one end of a handle and read them at the other end without using any
		799	additional framing.
		800
		801	The generated JSON text is guaranteed not to contain any newlines: While
		802	this module doesn't need delimiters after or between JSON texts to be
		803	able to read them, many other languages depend on that.
		804
		805	A simple RPC protocol that interoperates easily with others is to send
		806	JSON arrays (or objects, although arrays are usually the better choice as
		807	they mimic how function argument passing works) and a newline after each
		808	JSON text:
		809
		810	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		811	$handle->push_write ("\012");
		812
		813	An AnyEvent::Handle receiver would simply use the C<json> read type and
		814	rely on the fact that the newline will be skipped as leading whitespace:
		815
		816	$handle->push_read (json => sub { my $array = $_[1]; ... });
		817
		818	Other languages could read single lines terminated by a newline and pass
		819	this line into their JSON decoder of choice.
		820
		821	=cut
		822
		823	register_write_type json => sub {
		824	my ($self, $ref) = @_;
		825
		826	require JSON;
		827
		828	$self->{json} ? $self->{json}->encode ($ref)
		829	: JSON::encode_json ($ref)
		830	};
		831
		832	=item storable => $reference
		833
		834	Freezes the given reference using L<Storable> and writes it to the
		835	handle. Uses the C<nfreeze> format.
		836
		837	=cut
		838
		839	register_write_type storable => sub {
		840	my ($self, $ref) = @_;
		841
		842	require Storable;
		843
		844	pack "w/a*", Storable::nfreeze ($ref)
		845	};
		846
		847	=back
		848
		849	=item $handle->push_shutdown
		850
		851	Sometimes you know you want to close the socket after writing your data
		852	before it was actually written. One way to do that is to replace your
		853	C<on_drain> handler by a callback that shuts down the socket (and set
		854	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		855	replaces the C<on_drain> callback with:
		856
		857	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		858
		859	This simply shuts down the write side and signals an EOF condition to the
		860	the peer.
		861
		862	You can rely on the normal read queue and C<on_eof> handling
		863	afterwards. This is the cleanest way to close a connection.
		864
		865	=cut
		866
		867	sub push_shutdown {
		868	my ($self) = @_;
		869
		870	delete $self->{low_water_mark};
		871	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		872	}
		873
		874	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		875
		876	This function (not method) lets you add your own types to C<push_write>.
		877	Whenever the given C<type> is used, C<push_write> will invoke the code
		878	reference with the handle object and the remaining arguments.
		879
		880	The code reference is supposed to return a single octet string that will
		881	be appended to the write buffer.
		882
		883	Note that this is a function, and all types registered this way will be
		884	global, so try to use unique names.
		885
		886	=cut
		887
		888	#############################################################################
		889
		890	=back
		891
		892	=head2 READ QUEUE
		893
		894	AnyEvent::Handle manages two queues per handle, one for writing and one
		895	for reading.
		896
		897	The read queue is more complex than the write queue. It can be used in two
		898	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		899	a queue.
		900
		901	In the simple case, you just install an C<on_read> callback and whenever
		902	new data arrives, it will be called. You can then remove some data (if
		903	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		904	leave the data there if you want to accumulate more (e.g. when only a
		905	partial message has been received so far).
		906
		907	In the more complex case, you want to queue multiple callbacks. In this
		908	case, AnyEvent::Handle will call the first queued callback each time new
		909	data arrives (also the first time it is queued) and removes it when it has
		910	done its job (see C<push_read>, below).
		911
		912	This way you can, for example, push three line-reads, followed by reading
		913	a chunk of data, and AnyEvent::Handle will execute them in order.
		914
		915	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		916	the specified number of bytes which give an XML datagram.
		917
		918	# in the default state, expect some header bytes
		919	$handle->on_read (sub {
		920	# some data is here, now queue the length-header-read (4 octets)
		921	shift->unshift_read (chunk => 4, sub {
		922	# header arrived, decode
		923	my $len = unpack "N", $_[1];
		924
		925	# now read the payload
		926	shift->unshift_read (chunk => $len, sub {
		927	my $xml = $_[1];
		928	# handle xml
		929	});
		930	});
		931	});
		932
		933	Example 2: Implement a client for a protocol that replies either with "OK"
		934	and another line or "ERROR" for the first request that is sent, and 64
		935	bytes for the second request. Due to the availability of a queue, we can
		936	just pipeline sending both requests and manipulate the queue as necessary
		937	in the callbacks.
		938
		939	When the first callback is called and sees an "OK" response, it will
		940	C<unshift> another line-read. This line-read will be queued I<before> the
		941	64-byte chunk callback.
		942
		943	# request one, returns either "OK + extra line" or "ERROR"
		944	$handle->push_write ("request 1\015\012");
		945
		946	# we expect "ERROR" or "OK" as response, so push a line read
		947	$handle->push_read (line => sub {
		948	# if we got an "OK", we have to _prepend_ another line,
		949	# so it will be read before the second request reads its 64 bytes
		950	# which are already in the queue when this callback is called
		951	# we don't do this in case we got an error
		952	if ($_[1] eq "OK") {
		953	$_[0]->unshift_read (line => sub {
		954	my $response = $_[1];
		955	...
		956	});
38	}	957	}
39	});	958	});
40		959
41	# or use the constructor to pass the callback:	960	# request two, simply returns 64 octets
		961	$handle->push_write ("request 2\015\012");
42		962
43	my $ae_fh2 =	963	# simply read 64 bytes, always
44	AnyEvent::Handle->new (	964	$handle->push_read (chunk => 64, sub {
45	fh => \*STDIN,	965	my $response = $_[1];
46	on_eof => sub {	966	...
47	$cv->broadcast;	967	});
48	},	968
49	on_readline => sub {	969	=over 4
50	my ($ae_fh, @lines) = @_;	970
51	for (@lines) {	971	=cut
52	chomp;	972
53	print "Line: $_";	973	sub _drain_rbuf {
		974	my ($self) = @_;
		975
		976	# avoid recursion
		977	return if exists $self->{_skip_drain_rbuf};
		978	local $self->{_skip_drain_rbuf} = 1;
		979
		980	if (
		981	defined $self->{rbuf_max}
		982	&& $self->{rbuf_max} < length $self->{rbuf}
		983	) {
		984	$self->_error (Errno::ENOSPC, 1), return;
		985	}
		986
		987	while () {
		988	# we need to use a separate tls read buffer, as we must not receive data while
		989	# we are draining the buffer, and this can only happen with TLS.
		990	$self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
		991
		992	my $len = length $self->{rbuf};
		993
		994	if (my $cb = shift @{ $self->{_queue} }) {
		995	unless ($cb->($self)) {
		996	if ($self->{_eof}) {
		997	# no progress can be made (not enough data and no data forthcoming)
		998	$self->_error (Errno::EPIPE, 1), return;
54	}	999	}
		1000
		1001	unshift @{ $self->{_queue} }, $cb;
		1002	last;
55	}	1003	}
56	);
57
58	$cv->wait;
59
60	=head1 DESCRIPTION
61
62	This module is a helper module to make it easier to do non-blocking I/O
63	on filehandles (and sockets, see L<AnyEvent::Socket>).
64
65	The event loop is provided by L<AnyEvent>.
66
67	=head1 METHODS
68
69	=over 4
70
71	=item B<new (%args)>
72
73	The constructor has these arguments:
74
75	=over 4
76
77	=item fh => $filehandle
78
79	The filehandle this L<AnyEvent::Handle> object will operate on.
80
81	NOTE: The filehandle will be set to non-blocking.
82
83	=item read_block_size => $size
84
85	The default read block size use for reads via the C<on_read>
86	method.
87
88	=item on_read => $cb
89
90	=item on_eof => $cb
91
92	=item on_error => $cb
93
94	These are shortcuts, that will call the corresponding method and set the callback to C<$cb>.
95
96	=item on_readline => $cb
97
98	The C<readlines> method is called with the default seperator and C<$cb> as callback
99	for you.
100
101	=back
102
103	=cut
104
105	sub new {
106	my $this = shift;
107	my $class = ref($this) || $this;
108	my $self = {
109	read_block_size => 4096,
110	rbuf => '',
111	@_
112	};
113	bless $self, $class;
114
115	$self->{fh}->blocking (0) if $self->{fh};
116
117	if ($self->{on_read}) {
118	$self->on_read ($self->{on_read});
119
120	} elsif ($self->{on_readline}) {	1004	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	1005	last unless $len;
122		1006
		1007	$self->{on_read}($self);
		1008
		1009	if (
		1010	$len == length $self->{rbuf} # if no data has been consumed
		1011	&& !@{ $self->{_queue} } # and the queue is still empty
		1012	&& $self->{on_read} # but we still have on_read
		1013	) {
		1014	# no further data will arrive
		1015	# so no progress can be made
		1016	$self->_error (Errno::EPIPE, 1), return
		1017	if $self->{_eof};
		1018
		1019	last; # more data might arrive
		1020	}
		1021	} else {
		1022	# read side becomes idle
		1023	delete $self->{_rw} unless $self->{tls};
		1024	last;
		1025	}
		1026	}
		1027
123	} elsif ($self->{on_eof}) {	1028	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	1029	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	1030	$self->{on_eof}($self)
		1031	} else {
		1032	$self->_error (0, 1, "Unexpected end-of-file");
		1033	}
128	}	1034	}
129		1035
130	return $self	1036	# may need to restart read watcher
		1037	unless ($self->{_rw}) {
		1038	$self->start_read
		1039	if $self->{on_read} || @{ $self->{_queue} };
		1040	}
131	}	1041	}
132		1042
133	=item B<fh>	1043	=item $handle->on_read ($cb)
134		1044
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	1045	This replaces the currently set C<on_read> callback, or clears it (when
136		1046	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	1047	constructor.
138
139	sub fh { $_[0]->{fh} }
140
141	=item B<on_read ($callback)>
142
143	This method installs a C<$callback> that will be called
144	when new data arrived. You can access the read buffer via the C<rbuf>
145	method (see below).
146
147	The first argument of the C<$callback> will be the L<AnyEvent::Handle> object.
148		1048
149	=cut	1049	=cut
150		1050
151	sub on_read {	1051	sub on_read {
152	my ($self, $cb) = @_;	1052	my ($self, $cb) = @_;
		1053
153	$self->{on_read} = $cb;	1054	$self->{on_read} = $cb;
		1055	$self->_drain_rbuf if $cb;
		1056	}
154		1057
155	unless (defined $self->{on_read}) {	1058	=item $handle->rbuf
156	delete $self->{on_read_w};	1059
		1060	Returns the read buffer (as a modifiable lvalue).
		1061
		1062	You can access the read buffer directly as the C<< ->{rbuf} >>
		1063	member, if you want. However, the only operation allowed on the
		1064	read buffer (apart from looking at it) is removing data from its
		1065	beginning. Otherwise modifying or appending to it is not allowed and will
		1066	lead to hard-to-track-down bugs.
		1067
		1068	NOTE: The read buffer should only be used or modified if the C<on_read>,
		1069	C<push_read> or C<unshift_read> methods are used. The other read methods
		1070	automatically manage the read buffer.
		1071
		1072	=cut
		1073
		1074	sub rbuf : lvalue {
		1075	$_[0]{rbuf}
		1076	}
		1077
		1078	=item $handle->push_read ($cb)
		1079
		1080	=item $handle->unshift_read ($cb)
		1081
		1082	Append the given callback to the end of the queue (C<push_read>) or
		1083	prepend it (C<unshift_read>).
		1084
		1085	The callback is called each time some additional read data arrives.
		1086
		1087	It must check whether enough data is in the read buffer already.
		1088
		1089	If not enough data is available, it must return the empty list or a false
		1090	value, in which case it will be called repeatedly until enough data is
		1091	available (or an error condition is detected).
		1092
		1093	If enough data was available, then the callback must remove all data it is
		1094	interested in (which can be none at all) and return a true value. After returning
		1095	true, it will be removed from the queue.
		1096
		1097	=cut
		1098
		1099	our %RH;
		1100
		1101	sub register_read_type($$) {
		1102	$RH{$_[0]} = $_[1];
		1103	}
		1104
		1105	sub push_read {
		1106	my $self = shift;
		1107	my $cb = pop;
		1108
		1109	if (@_) {
		1110	my $type = shift;
		1111
		1112	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		1113	->($self, $cb, @_);
		1114	}
		1115
		1116	push @{ $self->{_queue} }, $cb;
		1117	$self->_drain_rbuf;
		1118	}
		1119
		1120	sub unshift_read {
		1121	my $self = shift;
		1122	my $cb = pop;
		1123
		1124	if (@_) {
		1125	my $type = shift;
		1126
		1127	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		1128	->($self, $cb, @_);
		1129	}
		1130
		1131
		1132	unshift @{ $self->{_queue} }, $cb;
		1133	$self->_drain_rbuf;
		1134	}
		1135
		1136	=item $handle->push_read (type => @args, $cb)
		1137
		1138	=item $handle->unshift_read (type => @args, $cb)
		1139
		1140	Instead of providing a callback that parses the data itself you can chose
		1141	between a number of predefined parsing formats, for chunks of data, lines
		1142	etc.
		1143
		1144	Predefined types are (if you have ideas for additional types, feel free to
		1145	drop by and tell us):
		1146
		1147	=over 4
		1148
		1149	=item chunk => $octets, $cb->($handle, $data)
		1150
		1151	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1152	data read to the callback. The callback will never be called with less
		1153	data.
		1154
		1155	Example: read 2 bytes.
		1156
		1157	$handle->push_read (chunk => 2, sub {
		1158	warn "yay ", unpack "H*", $_[1];
		1159	});
		1160
		1161	=cut
		1162
		1163	register_read_type chunk => sub {
		1164	my ($self, $cb, $len) = @_;
		1165
		1166	sub {
		1167	$len <= length $_[0]{rbuf} or return;
		1168	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		1169	1
		1170	}
		1171	};
		1172
		1173	=item line => [$eol, ]$cb->($handle, $line, $eol)
		1174
		1175	The callback will be called only once a full line (including the end of
		1176	line marker, C<$eol>) has been read. This line (excluding the end of line
		1177	marker) will be passed to the callback as second argument (C<$line>), and
		1178	the end of line marker as the third argument (C<$eol>).
		1179
		1180	The end of line marker, C<$eol>, can be either a string, in which case it
		1181	will be interpreted as a fixed record end marker, or it can be a regex
		1182	object (e.g. created by C<qr>), in which case it is interpreted as a
		1183	regular expression.
		1184
		1185	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		1186	undef), then C<qr|\015?\012|> is used (which is good for most internet
		1187	protocols).
		1188
		1189	Partial lines at the end of the stream will never be returned, as they are
		1190	not marked by the end of line marker.
		1191
		1192	=cut
		1193
		1194	register_read_type line => sub {
		1195	my ($self, $cb, $eol) = @_;
		1196
		1197	if (@_ < 3) {
		1198	# this is more than twice as fast as the generic code below
		1199	sub {
		1200	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1201
		1202	$cb->($_[0], $1, $2);
		1203	1
		1204	}
		1205	} else {
		1206	$eol = quotemeta $eol unless ref $eol;
		1207	$eol = qr|^(.*?)($eol)|s;
		1208
		1209	sub {
		1210	$_[0]{rbuf} =~ s/$eol// or return;
		1211
		1212	$cb->($_[0], $1, $2);
		1213	1
		1214	}
		1215	}
		1216	};
		1217
		1218	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1219
		1220	Makes a regex match against the regex object C<$accept> and returns
		1221	everything up to and including the match.
		1222
		1223	Example: read a single line terminated by '\n'.
		1224
		1225	$handle->push_read (regex => qr<\n>, sub { ... });
		1226
		1227	If C<$reject> is given and not undef, then it determines when the data is
		1228	to be rejected: it is matched against the data when the C<$accept> regex
		1229	does not match and generates an C<EBADMSG> error when it matches. This is
		1230	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1231	receive buffer overflow).
		1232
		1233	Example: expect a single decimal number followed by whitespace, reject
		1234	anything else (not the use of an anchor).
		1235
		1236	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1237
		1238	If C<$skip> is given and not C<undef>, then it will be matched against
		1239	the receive buffer when neither C<$accept> nor C<$reject> match,
		1240	and everything preceding and including the match will be accepted
		1241	unconditionally. This is useful to skip large amounts of data that you
		1242	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1243	have to start matching from the beginning. This is purely an optimisation
		1244	and is usually worth only when you expect more than a few kilobytes.
		1245
		1246	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1247	expect the header to be very large (it isn't in practise, but...), we use
		1248	a skip regex to skip initial portions. The skip regex is tricky in that
		1249	it only accepts something not ending in either \015 or \012, as these are
		1250	required for the accept regex.
		1251
		1252	$handle->push_read (regex =>
		1253	qr<\015\012\015\012>,
		1254	undef, # no reject
		1255	qr<^.*[^\015\012]>,
		1256	sub { ... });
		1257
		1258	=cut
		1259
		1260	register_read_type regex => sub {
		1261	my ($self, $cb, $accept, $reject, $skip) = @_;
		1262
		1263	my $data;
		1264	my $rbuf = \$self->{rbuf};
		1265
		1266	sub {
		1267	# accept
		1268	if ($$rbuf =~ $accept) {
		1269	$data .= substr $$rbuf, 0, $+[0], "";
		1270	$cb->($self, $data);
157	return;	1271	return 1;
		1272	}
		1273
		1274	# reject
		1275	if ($reject && $$rbuf =~ $reject) {
		1276	$self->_error (Errno::EBADMSG);
		1277	}
		1278
		1279	# skip
		1280	if ($skip && $$rbuf =~ $skip) {
		1281	$data .= substr $$rbuf, 0, $+[0], "";
		1282	}
		1283
		1284	()
158	}	1285	}
159		1286	};
160	$self->{on_read_w} =	1287
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1288	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1289
163	my $rbuf_len = length $self->{rbuf};	1290	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1291
165	if (defined $self->{read_size}) {	1292	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1293
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1294	=cut
168	} else {	1295
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1296	register_read_type netstring => sub {
		1297	my ($self, $cb) = @_;
		1298
		1299	sub {
		1300	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1301	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1302	$self->_error (Errno::EBADMSG);
170	}	1303	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1304	return;
		1305	}
172		1306
173	if (not defined $l) {	1307	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1308
178	} elsif ($l == 0) {	1309	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1310	my $string = $_[1];
180	delete $self->{on_read_w};	1311	$_[0]->unshift_read (chunk => 1, sub {
181		1312	if ($_[1] eq ",") {
		1313	$cb->($_[0], $string);
182	} else {	1314	} else {
183	$self->{on_read}->($self);	1315	$self->_error (Errno::EBADMSG);
		1316	}
		1317	});
		1318	});
		1319
		1320	1
		1321	}
		1322	};
		1323
		1324	=item packstring => $format, $cb->($handle, $string)
		1325
		1326	An octet string prefixed with an encoded length. The encoding C<$format>
		1327	uses the same format as a Perl C<pack> format, but must specify a single
		1328	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1329	optional C<!>, C<< < >> or C<< > >> modifier).
		1330
		1331	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1332	EPP uses a prefix of C<N> (4 octtes).
		1333
		1334	Example: read a block of data prefixed by its length in BER-encoded
		1335	format (very efficient).
		1336
		1337	$handle->push_read (packstring => "w", sub {
		1338	my ($handle, $data) = @_;
		1339	});
		1340
		1341	=cut
		1342
		1343	register_read_type packstring => sub {
		1344	my ($self, $cb, $format) = @_;
		1345
		1346	sub {
		1347	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1348	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1349	or return;
		1350
		1351	$format = length pack $format, $len;
		1352
		1353	# bypass unshift if we already have the remaining chunk
		1354	if ($format + $len <= length $_[0]{rbuf}) {
		1355	my $data = substr $_[0]{rbuf}, $format, $len;
		1356	substr $_[0]{rbuf}, 0, $format + $len, "";
		1357	$cb->($_[0], $data);
		1358	} else {
		1359	# remove prefix
		1360	substr $_[0]{rbuf}, 0, $format, "";
		1361
		1362	# read remaining chunk
		1363	$_[0]->unshift_read (chunk => $len, $cb);
		1364	}
		1365
		1366	1
		1367	}
		1368	};
		1369
		1370	=item json => $cb->($handle, $hash_or_arrayref)
		1371
		1372	Reads a JSON object or array, decodes it and passes it to the
		1373	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1374
		1375	If a C<json> object was passed to the constructor, then that will be used
		1376	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1377
		1378	This read type uses the incremental parser available with JSON version
		1379	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1380	dependency on your own: this module will load the JSON module, but
		1381	AnyEvent does not depend on it itself.
		1382
		1383	Since JSON texts are fully self-delimiting, the C<json> read and write
		1384	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1385	the C<json> write type description, above, for an actual example.
		1386
		1387	=cut
		1388
		1389	register_read_type json => sub {
		1390	my ($self, $cb) = @_;
		1391
		1392	my $json = $self->{json} ||=
		1393	eval { require JSON::XS; JSON::XS->new->utf8 }
		1394	|| do { require JSON; JSON->new->utf8 };
		1395
		1396	my $data;
		1397	my $rbuf = \$self->{rbuf};
		1398
		1399	sub {
		1400	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1401
		1402	if ($ref) {
		1403	$self->{rbuf} = $json->incr_text;
		1404	$json->incr_text = "";
		1405	$cb->($self, $ref);
		1406
		1407	1
		1408	} elsif ($@) {
		1409	# error case
		1410	$json->incr_skip;
		1411
		1412	$self->{rbuf} = $json->incr_text;
		1413	$json->incr_text = "";
		1414
		1415	$self->_error (Errno::EBADMSG);
		1416
		1417	()
		1418	} else {
		1419	$self->{rbuf} = "";
		1420
		1421	()
		1422	}
		1423	}
		1424	};
		1425
		1426	=item storable => $cb->($handle, $ref)
		1427
		1428	Deserialises a L<Storable> frozen representation as written by the
		1429	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1430	data).
		1431
		1432	Raises C<EBADMSG> error if the data could not be decoded.
		1433
		1434	=cut
		1435
		1436	register_read_type storable => sub {
		1437	my ($self, $cb) = @_;
		1438
		1439	require Storable;
		1440
		1441	sub {
		1442	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1443	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1444	or return;
		1445
		1446	my $format = length pack "w", $len;
		1447
		1448	# bypass unshift if we already have the remaining chunk
		1449	if ($format + $len <= length $_[0]{rbuf}) {
		1450	my $data = substr $_[0]{rbuf}, $format, $len;
		1451	substr $_[0]{rbuf}, 0, $format + $len, "";
		1452	$cb->($_[0], Storable::thaw ($data));
		1453	} else {
		1454	# remove prefix
		1455	substr $_[0]{rbuf}, 0, $format, "";
		1456
		1457	# read remaining chunk
		1458	$_[0]->unshift_read (chunk => $len, sub {
		1459	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1460	$cb->($_[0], $ref);
		1461	} else {
		1462	$self->_error (Errno::EBADMSG);
		1463	}
		1464	});
		1465	}
		1466
		1467	1
		1468	}
		1469	};
		1470
		1471	=back
		1472
		1473	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1474
		1475	This function (not method) lets you add your own types to C<push_read>.
		1476
		1477	Whenever the given C<type> is used, C<push_read> will invoke the code
		1478	reference with the handle object, the callback and the remaining
		1479	arguments.
		1480
		1481	The code reference is supposed to return a callback (usually a closure)
		1482	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1483
		1484	It should invoke the passed callback when it is done reading (remember to
		1485	pass C<$handle> as first argument as all other callbacks do that).
		1486
		1487	Note that this is a function, and all types registered this way will be
		1488	global, so try to use unique names.
		1489
		1490	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1491	search for C<register_read_type>)).
		1492
		1493	=item $handle->stop_read
		1494
		1495	=item $handle->start_read
		1496
		1497	In rare cases you actually do not want to read anything from the
		1498	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1499	any queued callbacks will be executed then. To start reading again, call
		1500	C<start_read>.
		1501
		1502	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1503	you change the C<on_read> callback or push/unshift a read callback, and it
		1504	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1505	there are any read requests in the queue.
		1506
		1507	These methods will have no effect when in TLS mode (as TLS doesn't support
		1508	half-duplex connections).
		1509
		1510	=cut
		1511
		1512	sub stop_read {
		1513	my ($self) = @_;
		1514
		1515	delete $self->{_rw} unless $self->{tls};
		1516	}
		1517
		1518	sub start_read {
		1519	my ($self) = @_;
		1520
		1521	unless ($self->{_rw} || $self->{_eof}) {
		1522	Scalar::Util::weaken $self;
		1523
		1524	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1525	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1526	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1527
		1528	if ($len > 0) {
		1529	$self->{_activity} = AnyEvent->now;
		1530
		1531	if ($self->{tls}) {
		1532	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1533
		1534	&_dotls ($self);
		1535	} else {
		1536	$self->_drain_rbuf;
		1537	}
		1538
		1539	} elsif (defined $len) {
		1540	delete $self->{_rw};
		1541	$self->{_eof} = 1;
		1542	$self->_drain_rbuf;
		1543
		1544	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1545	return $self->_error ($!, 1);
184	}	1546	}
185	});	1547	});
		1548	}
186	}	1549	}
187		1550
188	=item B<on_error ($callback)>	1551	our $ERROR_SYSCALL;
		1552	our $ERROR_WANT_READ;
189		1553
190	Whenever a read or write operation resulted in an error the C<$callback>
191	will be called.
192
193	The first argument of C<$callback> will be the L<AnyEvent::Handle> object itself.
194	The error is given as errno in C<$!>.
195
196	=cut
197
198	sub on_error {	1554	sub _tls_error {
199	$_[0]->{on_error} = $_[1];
200	}
201
202	=item B<on_eof ($callback)>
203
204	Installs the C<$callback> that will be called when the end of file is
205	encountered in a read operation this C<$callback> will be called. The first
206	argument will be the L<AnyEvent::Handle> object itself.
207
208	=cut
209
210	sub on_eof {
211	$_[0]->{on_eof} = $_[1];
212	}
213
214	=item B<rbuf>
215
216	Returns a reference to the read buffer.
217
218	NOTE: The read buffer should only be used or modified if the C<on_read>
219	method is used directly. The C<read> and C<readlines> methods will provide
220	the read data to their callbacks.
221
222	=cut
223
224	sub rbuf : lvalue {
225	$_[0]->{rbuf}
226	}
227
228	=item B<read ($len, $callback)>
229
230	Will read exactly C<$len> bytes from the filehandle and call the C<$callback>
231	if done so. The first argument to the C<$callback> will be the L<AnyEvent::Handle>
232	object itself and the second argument the read data.
233
234	NOTE: This method will override any callbacks installed via the C<on_read> method.
235
236	=cut
237
238	sub read {
239	my ($self, $len, $cb) = @_;	1555	my ($self, $err) = @_;
240		1556
241	$self->{read_cb} = $cb;	1557	return $self->_error ($!, 1)
242	my $old_blk_size = $self->{read_block_size};	1558	if $err == Net::SSLeay::ERROR_SYSCALL ();
243	$self->{read_block_size} = $len;
244		1559
245	$self->on_read (sub {	1560	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";
247		1561
248	if ($len == length $_[0]->{rbuf}) {	1562	# reduce error string to look less scary
249	$_[0]->{read_block_size} = $old_blk_size;	1563	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
250	$_[0]->on_read (undef);	1564
251	$_[0]->{read_cb}->($_[0], (substr $self->{rbuf}, 0, $len, ''));	1565	if ($self->{_on_starttls}) {
		1566	(delete $self->{_on_starttls})->($self, undef, $err);
		1567	&_freetls;
		1568	} else {
		1569	&_freetls;
		1570	$self->_error (Errno::EPROTO, 1, $err);
		1571	}
		1572	}
		1573
		1574	# poll the write BIO and send the data if applicable
		1575	# also decode read data if possible
		1576	# this is basiclaly our TLS state machine
		1577	# more efficient implementations are possible with openssl,
		1578	# but not with the buggy and incomplete Net::SSLeay.
		1579	sub _dotls {
		1580	my ($self) = @_;
		1581
		1582	my $tmp;
		1583
		1584	if (length $self->{_tls_wbuf}) {
		1585	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
		1586	substr $self->{_tls_wbuf}, 0, $tmp, "";
252	}	1587	}
		1588
		1589	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1590	return $self->_tls_error ($tmp)
		1591	if $tmp != $ERROR_WANT_READ
		1592	&& ($tmp != $ERROR_SYSCALL || $!);
253	});	1593	}
254	}
255		1594
256	=item B<readlines ($callback)>	1595	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1596	unless (length $tmp) {
		1597	$self->{_on_starttls}
		1598	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1599	&_freetls;
257		1600
258	=item B<readlines ($sep, $callback)>	1601	if ($self->{on_stoptls}) {
259		1602	$self->{on_stoptls}($self);
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1603	return;
261	if C<$sep> is not provided. C<$sep> will be used as "line" seperator.	1604	} else {
262		1605	# let's treat SSL-eof as we treat normal EOF
263	The C<$callback> will be called when at least one	1606	delete $self->{_rw};
264	line could be read. The first argument to the C<$callback> will be the L<AnyEvent::Handle>
265	object itself and the rest of the arguments will be the read lines.
266
267	NOTE: This method will override any callbacks installed via the C<on_read> method.
268
269	=cut
270
271	sub readlines {
272	my ($self, $sep, $cb) = @_;
273
274	if (ref $sep) {
275	$cb = $sep;
276	$sep = "\n";
277
278	} elsif (not defined $sep) {
279	$sep = "\n";
280	}
281
282	my $sep_len = length $sep;
283
284	$self->{on_readline} = $cb;
285
286	$self->on_read (sub {
287	my @lines;
288	my $rb = \$_[0]->{rbuf};
289	my $pos;
290	while (($pos = index ($$rb, $sep)) >= 0) {
291	push @lines, substr $$rb, 0, $pos + $sep_len, '';
292	}
293	$self->{on_readline}->($_[0], @lines);
294	});
295	}
296
297	=item B<write ($data)>
298
299	=item B<write ($callback)>
300
301	=item B<write ($data, $callback)>
302
303	This method will write C<$data> to the filehandle and call the C<$callback>
304	afterwards. If only C<$callback> is provided it will be called when the
305	write buffer becomes empty the next time (or immediately if it already is empty).
306
307	=cut
308
309	sub write {
310	my ($self, $data, $cb) = @_;
311	if (ref $data) { $cb = $data; undef $data }
312	push @{$self->{write_bufs}}, [$data, $cb];
313	$self->_check_writer;
314	}
315
316	sub _check_writer {
317	my ($self) = @_;
318
319	if ($self->{write_w}) {
320	unless ($self->{write_cb}) {
321	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {
322	my $wba = shift @{$self->{write_bufs}};
323	$self->{wbuf} .= $wba->[0];	1607	$self->{_eof} = 1;
324	}	1608	}
325	}	1609	}
326	return;	1610
		1611	$self->{_tls_rbuf} .= $tmp;
		1612	$self->_drain_rbuf;
		1613	$self->{tls} or return; # tls session might have gone away in callback
		1614	}
		1615
		1616	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1617	return $self->_tls_error ($tmp)
		1618	if $tmp != $ERROR_WANT_READ
		1619	&& ($tmp != $ERROR_SYSCALL || $!);
		1620
		1621	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1622	$self->{wbuf} .= $tmp;
		1623	$self->_drain_wbuf;
		1624	}
		1625
		1626	$self->{_on_starttls}
		1627	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
		1628	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
		1629	}
		1630
		1631	=item $handle->starttls ($tls[, $tls_ctx])
		1632
		1633	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1634	object is created, you can also do that at a later time by calling
		1635	C<starttls>.
		1636
		1637	Starting TLS is currently an asynchronous operation - when you push some
		1638	write data and then call C<< ->starttls >> then TLS negotiation will start
		1639	immediately, after which the queued write data is then sent.
		1640
		1641	The first argument is the same as the C<tls> constructor argument (either
		1642	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1643
		1644	The second argument is the optional C<AnyEvent::TLS> object that is used
		1645	when AnyEvent::Handle has to create its own TLS connection object, or
		1646	a hash reference with C<< key => value >> pairs that will be used to
		1647	construct a new context.
		1648
		1649	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1650	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1651	changed to your liking. Note that the handshake might have already started
		1652	when this function returns.
		1653
		1654	If it an error to start a TLS handshake more than once per
		1655	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1656
		1657	=cut
		1658
		1659	our %TLS_CACHE; #TODO not yet documented, should we?
		1660
		1661	sub starttls {
		1662	my ($self, $ssl, $ctx) = @_;
		1663
		1664	require Net::SSLeay;
		1665
		1666	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
		1667	if $self->{tls};
		1668
		1669	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1670	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1671
		1672	$ctx ||= $self->{tls_ctx};
		1673
		1674	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1675
		1676	if ("HASH" eq ref $ctx) {
		1677	require AnyEvent::TLS;
		1678
		1679	if ($ctx->{cache}) {
		1680	my $key = $ctx+0;
		1681	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1682	} else {
		1683	$ctx = new AnyEvent::TLS %$ctx;
		1684	}
		1685	}
327	}	1686
		1687	$self->{tls_ctx} = $ctx || TLS_CTX ();
		1688	$self->{tls} = $ssl = $self->{tls_ctx}->_get_session ($ssl, $self, $self->{peername});
328		1689
329	my $wba = shift @{$self->{write_bufs}}	1690	# basically, this is deep magic (because SSL_read should have the same issues)
330	or return;	1691	# but the openssl maintainers basically said: "trust us, it just works".
		1692	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1693	# and mismaintained ssleay-module doesn't even offer them).
		1694	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1695	#
		1696	# in short: this is a mess.
		1697	#
		1698	# note that we do not try to keep the length constant between writes as we are required to do.
		1699	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1700	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1701	# have identity issues in that area.
		1702	# Net::SSLeay::CTX_set_mode ($ssl,
		1703	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1704	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1705	Net::SSLeay::CTX_set_mode ($ssl, 1|2);
331		1706
332	unless (defined $wba->[0]) {	1707	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
333	$wba->[1]->($self) if $wba->[1];	1708	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
334	$self->_check_writer;	1709
335	return;	1710	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
		1711
		1712	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
		1713	if $self->{on_starttls};
		1714
		1715	&_dotls; # need to trigger the initial handshake
		1716	$self->start_read; # make sure we actually do read
		1717	}
		1718
		1719	=item $handle->stoptls
		1720
		1721	Shuts down the SSL connection - this makes a proper EOF handshake by
		1722	sending a close notify to the other side, but since OpenSSL doesn't
		1723	support non-blocking shut downs, it is not possible to re-use the stream
		1724	afterwards.
		1725
		1726	=cut
		1727
		1728	sub stoptls {
		1729	my ($self) = @_;
		1730
		1731	if ($self->{tls}) {
		1732	Net::SSLeay::shutdown ($self->{tls});
		1733
		1734	&_dotls;
		1735
		1736	# # we don't give a shit. no, we do, but we can't. no...#d#
		1737	# # we, we... have to use openssl :/#d#
		1738	# &_freetls;#d#
		1739	}
		1740	}
		1741
		1742	sub _freetls {
		1743	my ($self) = @_;
		1744
		1745	return unless $self->{tls};
		1746
		1747	$self->{tls_ctx}->_put_session (delete $self->{tls});
336	}	1748
		1749	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		1750	}
337		1751
338	$self->{wbuf} = $wba->[0];	1752	sub DESTROY {
339	$self->{write_cb} = $wba->[1];	1753	my ($self) = @_;
340		1754
341	$self->{write_w} =	1755	&_freetls;
342	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1756
		1757	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1758
		1759	if ($linger && length $self->{wbuf} && $self->{fh}) {
		1760	my $fh = delete $self->{fh};
		1761	my $wbuf = delete $self->{wbuf};
		1762
		1763	my @linger;
		1764
		1765	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
343	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1766	my $len = syswrite $fh, $wbuf, length $wbuf;
344		1767
345	if (not defined $l) {	1768	if ($len > 0) {
346	return if $! == EAGAIN || $! == EINTR;	1769	substr $wbuf, 0, $len, "";
347	delete $self->{write_w};
348	$self->{on_error}->($self) if $self->{on_error};
349
350	} else {	1770	} else {
351	substr $self->{wbuf}, 0, $l, '';	1771	@linger = (); # end
352
353	if (length ($self->{wbuf}) == 0) {
354	$self->{write_cb}->($self) if $self->{write_cb};
355
356	delete $self->{write_w};
357	delete $self->{wbuf};
358	delete $self->{write_cb};
359
360	$self->_check_writer;
361	}
362	}	1772	}
363	});	1773	});
		1774	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1775	@linger = ();
		1776	});
		1777	}
		1778	}
		1779
		1780	=item $handle->destroy
		1781
		1782	Shuts down the handle object as much as possible - this call ensures that
		1783	no further callbacks will be invoked and as many resources as possible
		1784	will be freed. You must not call any methods on the object afterwards.
		1785
		1786	Normally, you can just "forget" any references to an AnyEvent::Handle
		1787	object and it will simply shut down. This works in fatal error and EOF
		1788	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1789	callback, so when you want to destroy the AnyEvent::Handle object from
		1790	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1791	that case.
		1792
		1793	Destroying the handle object in this way has the advantage that callbacks
		1794	will be removed as well, so if those are the only reference holders (as
		1795	is common), then one doesn't need to do anything special to break any
		1796	reference cycles.
		1797
		1798	The handle might still linger in the background and write out remaining
		1799	data, as specified by the C<linger> option, however.
		1800
		1801	=cut
		1802
		1803	sub destroy {
		1804	my ($self) = @_;
		1805
		1806	$self->DESTROY;
		1807	%$self = ();
		1808	}
		1809
		1810	=item AnyEvent::Handle::TLS_CTX
		1811
		1812	This function creates and returns the AnyEvent::TLS object used by default
		1813	for TLS mode.
		1814
		1815	The context is created by calling L<AnyEvent::TLS> without any arguments.
		1816
		1817	=cut
		1818
		1819	our $TLS_CTX;
		1820
		1821	sub TLS_CTX() {
		1822	$TLS_CTX ||= do {
		1823	require AnyEvent::TLS;
		1824
		1825	new AnyEvent::TLS
		1826	}
364	}	1827	}
365		1828
366	=back	1829	=back
367		1830
		1831
		1832	=head1 NONFREQUENTLY ASKED QUESTIONS
		1833
		1834	=over 4
		1835
		1836	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1837	still get further invocations!
		1838
		1839	That's because AnyEvent::Handle keeps a reference to itself when handling
		1840	read or write callbacks.
		1841
		1842	It is only safe to "forget" the reference inside EOF or error callbacks,
		1843	from within all other callbacks, you need to explicitly call the C<<
		1844	->destroy >> method.
		1845
		1846	=item I get different callback invocations in TLS mode/Why can't I pause
		1847	reading?
		1848
		1849	Unlike, say, TCP, TLS connections do not consist of two independent
		1850	communication channels, one for each direction. Or put differently. The
		1851	read and write directions are not independent of each other: you cannot
		1852	write data unless you are also prepared to read, and vice versa.
		1853
		1854	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1855	callback invocations when you are not expecting any read data - the reason
		1856	is that AnyEvent::Handle always reads in TLS mode.
		1857
		1858	During the connection, you have to make sure that you always have a
		1859	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1860	connection (or when you no longer want to use it) you can call the
		1861	C<destroy> method.
		1862
		1863	=item How do I read data until the other side closes the connection?
		1864
		1865	If you just want to read your data into a perl scalar, the easiest way
		1866	to achieve this is by setting an C<on_read> callback that does nothing,
		1867	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1868	will be in C<$_[0]{rbuf}>:
		1869
		1870	$handle->on_read (sub { });
		1871	$handle->on_eof (undef);
		1872	$handle->on_error (sub {
		1873	my $data = delete $_[0]{rbuf};
		1874	});
		1875
		1876	The reason to use C<on_error> is that TCP connections, due to latencies
		1877	and packets loss, might get closed quite violently with an error, when in
		1878	fact, all data has been received.
		1879
		1880	It is usually better to use acknowledgements when transferring data,
		1881	to make sure the other side hasn't just died and you got the data
		1882	intact. This is also one reason why so many internet protocols have an
		1883	explicit QUIT command.
		1884
		1885	=item I don't want to destroy the handle too early - how do I wait until
		1886	all data has been written?
		1887
		1888	After writing your last bits of data, set the C<on_drain> callback
		1889	and destroy the handle in there - with the default setting of
		1890	C<low_water_mark> this will be called precisely when all data has been
		1891	written to the socket:
		1892
		1893	$handle->push_write (...);
		1894	$handle->on_drain (sub {
		1895	warn "all data submitted to the kernel\n";
		1896	undef $handle;
		1897	});
		1898
		1899	If you just want to queue some data and then signal EOF to the other side,
		1900	consider using C<< ->push_shutdown >> instead.
		1901
		1902	=item I want to contact a TLS/SSL server, I don't care about security.
		1903
		1904	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		1905	simply connect to it and then create the AnyEvent::Handle with the C<tls>
		1906	parameter:
		1907
		1908	tcp_connect $host, $port, sub {
		1909	my ($fh) = @_;
		1910
		1911	my $handle = new AnyEvent::Handle
		1912	fh => $fh,
		1913	tls => "connect",
		1914	on_error => sub { ... };
		1915
		1916	$handle->push_write (...);
		1917	};
		1918
		1919	=item I want to contact a TLS/SSL server, I do care about security.
		1920
		1921	Then you should additionally enable certificate verification, including
		1922	peername verification, if the protocol you use supports it (see
		1923	L<AnyEvent::TLS>, C<verify_peername>).
		1924
		1925	E.g. for HTTPS:
		1926
		1927	tcp_connect $host, $port, sub {
		1928	my ($fh) = @_;
		1929
		1930	my $handle = new AnyEvent::Handle
		1931	fh => $fh,
		1932	peername => $host,
		1933	tls => "connect",
		1934	tls_ctx => { verify => 1, verify_peername => "https" },
		1935	...
		1936
		1937	Note that you must specify the hostname you connected to (or whatever
		1938	"peername" the protocol needs) as the C<peername> argument, otherwise no
		1939	peername verification will be done.
		1940
		1941	The above will use the system-dependent default set of trusted CA
		1942	certificates. If you want to check against a specific CA, add the
		1943	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		1944
		1945	tls_ctx => {
		1946	verify => 1,
		1947	verify_peername => "https",
		1948	ca_file => "my-ca-cert.pem",
		1949	},
		1950
		1951	=item I want to create a TLS/SSL server, how do I do that?
		1952
		1953	Well, you first need to get a server certificate and key. You have
		1954	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		1955	self-signed certificate (cheap. check the search engine of your choice,
		1956	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		1957	nice program for that purpose).
		1958
		1959	Then create a file with your private key (in PEM format, see
		1960	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		1961	file should then look like this:
		1962
		1963	-----BEGIN RSA PRIVATE KEY-----
		1964	...header data
		1965	... lots of base64'y-stuff
		1966	-----END RSA PRIVATE KEY-----
		1967
		1968	-----BEGIN CERTIFICATE-----
		1969	... lots of base64'y-stuff
		1970	-----END CERTIFICATE-----
		1971
		1972	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		1973	specify this file as C<cert_file>:
		1974
		1975	tcp_server undef, $port, sub {
		1976	my ($fh) = @_;
		1977
		1978	my $handle = new AnyEvent::Handle
		1979	fh => $fh,
		1980	tls => "accept",
		1981	tls_ctx => { cert_file => "my-server-keycert.pem" },
		1982	...
		1983
		1984	When you have intermediate CA certificates that your clients might not
		1985	know about, just append them to the C<cert_file>.
		1986
		1987	=back
		1988
		1989
		1990	=head1 SUBCLASSING AnyEvent::Handle
		1991
		1992	In many cases, you might want to subclass AnyEvent::Handle.
		1993
		1994	To make this easier, a given version of AnyEvent::Handle uses these
		1995	conventions:
		1996
		1997	=over 4
		1998
		1999	=item * all constructor arguments become object members.
		2000
		2001	At least initially, when you pass a C<tls>-argument to the constructor it
		2002	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2003	mutated later on (for example C<tls> will hold the TLS connection object).
		2004
		2005	=item * other object member names are prefixed with an C<_>.
		2006
		2007	All object members not explicitly documented (internal use) are prefixed
		2008	with an underscore character, so the remaining non-C<_>-namespace is free
		2009	for use for subclasses.
		2010
		2011	=item * all members not documented here and not prefixed with an underscore
		2012	are free to use in subclasses.
		2013
		2014	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2015	member variables, but thats just life, at least it is documented.
		2016
		2017	=back
		2018
368	=head1 AUTHOR	2019	=head1 AUTHOR
369		2020
370	Robin Redeker, C<< <elmex at ta-sa.org> >>	2021	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
371		2022
372	=cut	2023	=cut
373		2024
374	1; # End of AnyEvent::Handle	2025	1; # End of AnyEvent::Handle

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines