[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent/Handle.pm

Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.90 by root, Mon Sep 29 02:08:57 2008 UTC vs.
Revision 1.142 by root, Mon Jul 6 20:24:47 2009 UTC

…		…
14		14
15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent	15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
16		16
17	=cut	17	=cut
18		18
19	our $VERSION = 4.234;	19	our $VERSION = 4.452;
20		20
21	=head1 SYNOPSIS	21	=head1 SYNOPSIS
22		22
23	use AnyEvent;	23	use AnyEvent;
24	use AnyEvent::Handle;	24	use AnyEvent::Handle;
…		…
27		27
28	my $handle =	28	my $handle =
29	AnyEvent::Handle->new (	29	AnyEvent::Handle->new (
30	fh => \*STDIN,	30	fh => \*STDIN,
31	on_eof => sub {	31	on_eof => sub {
32	$cv->broadcast;	32	$cv->send;
33	},	33	},
34	);	34	);
35		35
36	# send some request line	36	# send some request line
37	$handle->push_write ("getinfo\015\012");	37	$handle->push_write ("getinfo\015\012");
…		…
59	treatment of characters applies to this module as well.	59	treatment of characters applies to this module as well.
60		60
61	All callbacks will be invoked with the handle object as their first	61	All callbacks will be invoked with the handle object as their first
62	argument.	62	argument.
63		63
64	=head2 SIGPIPE is not handled by this module
65
66	SIGPIPE is not handled by this module, so one of the practical
67	requirements of using it is to ignore SIGPIPE (C<$SIG{PIPE} =
68	'IGNORE'>). At least, this is highly recommend in a networked program: If
69	you use AnyEvent::Handle in a filter program (like sort), exiting on
70	SIGPIPE is probably the right thing to do.
71
72	=head1 METHODS	64	=head1 METHODS
73		65
74	=over 4	66	=over 4
75		67
76	=item B<new (%args)>	68	=item $handle = B<new> AnyEvent::TLS fh => $filehandle, key => value...
77		69
78	The constructor supports these arguments (all as key => value pairs).	70	The constructor supports these arguments (all as C<< key => value >> pairs).
79		71
80	=over 4	72	=over 4
81		73
82	=item fh => $filehandle [MANDATORY]	74	=item fh => $filehandle [MANDATORY]
83		75
…		…
92	Set the callback to be called when an end-of-file condition is detected,	84	Set the callback to be called when an end-of-file condition is detected,
93	i.e. in the case of a socket, when the other side has closed the	85	i.e. in the case of a socket, when the other side has closed the
94	connection cleanly.	86	connection cleanly.
95		87
96	For sockets, this just means that the other side has stopped sending data,	88	For sockets, this just means that the other side has stopped sending data,
97	you can still try to write data, and, in fact, one can return from the eof	89	you can still try to write data, and, in fact, one can return from the EOF
98	callback and continue writing data, as only the read part has been shut	90	callback and continue writing data, as only the read part has been shut
99	down.	91	down.
100		92
101	While not mandatory, it is I<highly> recommended to set an eof callback,	93	While not mandatory, it is I<highly> recommended to set an EOF callback,
102	otherwise you might end up with a closed socket while you are still	94	otherwise you might end up with a closed socket while you are still
103	waiting for data.	95	waiting for data.
104		96
105	If an EOF condition has been detected but no C<on_eof> callback has been	97	If an EOF condition has been detected but no C<on_eof> callback has been
106	set, then a fatal error will be raised with C<$!> set to <0>.	98	set, then a fatal error will be raised with C<$!> set to <0>.
107		99
108	=item on_error => $cb->($handle, $fatal)	100	=item on_error => $cb->($handle, $fatal, $message)
109		101
110	This is the error callback, which is called when, well, some error	102	This is the error callback, which is called when, well, some error
111	occured, such as not being able to resolve the hostname, failure to	103	occured, such as not being able to resolve the hostname, failure to
112	connect or a read error.	104	connect or a read error.
113		105
…		…
115	fatal errors the handle object will be shut down and will not be usable	107	fatal errors the handle object will be shut down and will not be usable
116	(but you are free to look at the current C<< ->rbuf >>). Examples of fatal	108	(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
117	errors are an EOF condition with active (but unsatisifable) read watchers	109	errors are an EOF condition with active (but unsatisifable) read watchers
118	(C<EPIPE>) or I/O errors.	110	(C<EPIPE>) or I/O errors.
119		111
		112	AnyEvent::Handle tries to find an appropriate error code for you to check
		113	against, but in some cases (TLS errors), this does not work well. It is
		114	recommended to always output the C<$message> argument in human-readable
		115	error messages (it's usually the same as C<"$!">).
		116
120	Non-fatal errors can be retried by simply returning, but it is recommended	117	Non-fatal errors can be retried by simply returning, but it is recommended
121	to simply ignore this parameter and instead abondon the handle object	118	to simply ignore this parameter and instead abondon the handle object
122	when this callback is invoked. Examples of non-fatal errors are timeouts	119	when this callback is invoked. Examples of non-fatal errors are timeouts
123	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).	120	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
124		121
125	On callback entrance, the value of C<$!> contains the operating system	122	On callback entrance, the value of C<$!> contains the operating system
126	error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).	123	error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		124	C<EPROTO>).
127		125
128	While not mandatory, it is I<highly> recommended to set this callback, as	126	While not mandatory, it is I<highly> recommended to set this callback, as
129	you will not be notified of errors otherwise. The default simply calls	127	you will not be notified of errors otherwise. The default simply calls
130	C<croak>.	128	C<croak>.
131		129
…		…
135	and no read request is in the queue (unlike read queue callbacks, this	133	and no read request is in the queue (unlike read queue callbacks, this
136	callback will only be called when at least one octet of data is in the	134	callback will only be called when at least one octet of data is in the
137	read buffer).	135	read buffer).
138		136
139	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	137	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
140	method or access the C<$handle->{rbuf}> member directly.	138	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		139	must not enlarge or modify the read buffer, you can only remove data at
		140	the beginning from it.
141		141
142	When an EOF condition is detected then AnyEvent::Handle will first try to	142	When an EOF condition is detected then AnyEvent::Handle will first try to
143	feed all the remaining data to the queued callbacks and C<on_read> before	143	feed all the remaining data to the queued callbacks and C<on_read> before
144	calling the C<on_eof> callback. If no progress can be made, then a fatal	144	calling the C<on_eof> callback. If no progress can be made, then a fatal
145	error will be raised (with C<$!> set to C<EPIPE>).	145	error will be raised (with C<$!> set to C<EPIPE>).
…		…
240	write data and will install a watcher that will write this data to the	240	write data and will install a watcher that will write this data to the
241	socket. No errors will be reported (this mostly matches how the operating	241	socket. No errors will be reported (this mostly matches how the operating
242	system treats outstanding data at socket close time).	242	system treats outstanding data at socket close time).
243		243
244	This will not work for partial TLS data that could not be encoded	244	This will not work for partial TLS data that could not be encoded
245	yet. This data will be lost.	245	yet. This data will be lost. Calling the C<stoptls> method in time might
		246	help.
		247
		248	=item peername => $string
		249
		250	A string used to identify the remote site - usually the DNS hostname
		251	(I<not> IDN!) used to create the connection, rarely the IP address.
		252
		253	Apart from being useful in error messages, this string is also used in TLS
		254	peername verification (see C<verify_peername> in L<AnyEvent::TLS>).
246		255
247	=item tls => "accept" \| "connect" \| Net::SSLeay::SSL object	256	=item tls => "accept" \| "connect" \| Net::SSLeay::SSL object
248		257
249	When this parameter is given, it enables TLS (SSL) mode, that means	258	When this parameter is given, it enables TLS (SSL) mode, that means
250	AnyEvent will start a TLS handshake as soon as the conenction has been	259	AnyEvent will start a TLS handshake as soon as the conenction has been
251	established and will transparently encrypt/decrypt data afterwards.	260	established and will transparently encrypt/decrypt data afterwards.
		261
		262	All TLS protocol errors will be signalled as C<EPROTO>, with an
		263	appropriate error message.
252		264
253	TLS mode requires Net::SSLeay to be installed (it will be loaded	265	TLS mode requires Net::SSLeay to be installed (it will be loaded
254	automatically when you try to create a TLS handle): this module doesn't	266	automatically when you try to create a TLS handle): this module doesn't
255	have a dependency on that module, so if your module requires it, you have	267	have a dependency on that module, so if your module requires it, you have
256	to add the dependency yourself.	268	to add the dependency yourself.
…		…
260	mode.	272	mode.
261		273
262	You can also provide your own TLS connection object, but you have	274	You can also provide your own TLS connection object, but you have
263	to make sure that you call either C<Net::SSLeay::set_connect_state>	275	to make sure that you call either C<Net::SSLeay::set_connect_state>
264	or C<Net::SSLeay::set_accept_state> on it before you pass it to	276	or C<Net::SSLeay::set_accept_state> on it before you pass it to
265	AnyEvent::Handle.	277	AnyEvent::Handle. Also, this module will take ownership of this connection
		278	object.
		279
		280	At some future point, AnyEvent::Handle might switch to another TLS
		281	implementation, then the option to use your own session object will go
		282	away.
		283
		284	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		285	passing in the wrong integer will lead to certain crash. This most often
		286	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		287	segmentation fault.
266		288
267	See the C<< ->starttls >> method for when need to start TLS negotiation later.	289	See the C<< ->starttls >> method for when need to start TLS negotiation later.
268		290
269	=item tls_ctx => $ssl_ctx	291	=item tls_ctx => $anyevent_tls
270		292
271	Use the given C<Net::SSLeay::CTX> object to create the new TLS connection	293	Use the given C<AnyEvent::TLS> object to create the new TLS connection
272	(unless a connection object was specified directly). If this parameter is	294	(unless a connection object was specified directly). If this parameter is
273	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	295	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		296
		297	Instead of an object, you can also specify a hash reference with C<< key
		298	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		299	new TLS context object.
		300
		301	=item on_starttls => $cb->($handle, $success)
		302
		303	This callback will be invoked when the TLS/SSL handshake has finished. If
		304	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		305	(C<on_stoptls> will not be called in this case).
		306
		307	The session in C<< $handle->{tls} >> can still be examined in this
		308	callback, even when the handshake was not successful.
		309
		310	=item on_stoptls => $cb->($handle)
		311
		312	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		313	set, then it will be invoked after freeing the TLS session. If it is not,
		314	then a TLS shutdown condition will be treated like a normal EOF condition
		315	on the handle.
		316
		317	The session in C<< $handle->{tls} >> can still be examined in this
		318	callback.
		319
		320	This callback will only be called on TLS shutdowns, not when the
		321	underlying handle signals EOF.
274		322
275	=item json => JSON or JSON::XS object	323	=item json => JSON or JSON::XS object
276		324
277	This is the json coder object used by the C<json> read and write types.	325	This is the json coder object used by the C<json> read and write types.
278		326
…		…
281	texts.	329	texts.
282		330
283	Note that you are responsible to depend on the JSON module if you want to	331	Note that you are responsible to depend on the JSON module if you want to
284	use this functionality, as AnyEvent does not have a dependency itself.	332	use this functionality, as AnyEvent does not have a dependency itself.
285		333
286	=item filter_r => $cb
287
288	=item filter_w => $cb
289
290	These exist, but are undocumented at this time. (They are used internally
291	by the TLS code).
292
293	=back	334	=back
294		335
295	=cut	336	=cut
296		337
297	sub new {	338	sub new {
298	my $class = shift;	339	my $class = shift;
299
300	my $self = bless { @_ }, $class;	340	my $self = bless { @_ }, $class;
301		341
302	$self->{fh} or Carp::croak "mandatory argument fh is missing";	342	$self->{fh} or Carp::croak "mandatory argument fh is missing";
303		343
304	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	344	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
305
306	if ($self->{tls}) {
307	require Net::SSLeay;
308	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});
309	}
310		345
311	$self->{_activity} = AnyEvent->now;	346	$self->{_activity} = AnyEvent->now;
312	$self->_timeout;	347	$self->_timeout;
313		348
		349	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		350
		351	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		352	if $self->{tls};
		353
314	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};	354	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
315	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
316		355
317	$self->start_read	356	$self->start_read
318	if $self->{on_read};	357	if $self->{on_read};
319		358
320	$self	359	$self->{fh} && $self
321	}	360	}
322		361
323	sub _shutdown {	362	sub _shutdown {
324	my ($self) = @_;	363	my ($self) = @_;
325		364
326	delete $self->{_tw};	365	delete @$self{qw(_tw _rw _ww fh wbuf on_read _queue)};
327	delete $self->{_rw};	366	$self->{_eof} = 1; # tell starttls et. al to stop trying
328	delete $self->{_ww};
329	delete $self->{fh};
330		367
331	$self->stoptls;	368	&_freetls;
332
333	delete $self->{on_read};
334	delete $self->{_queue};
335	}	369	}
336		370
337	sub _error {	371	sub _error {
338	my ($self, $errno, $fatal) = @_;	372	my ($self, $errno, $fatal, $message) = @_;
339		373
340	$self->_shutdown	374	$self->_shutdown
341	if $fatal;	375	if $fatal;
342		376
343	$! = $errno;	377	$! = $errno;
		378	$message \|\|= "$!";
344		379
345	if ($self->{on_error}) {	380	if ($self->{on_error}) {
346	$self->{on_error}($self, $fatal);	381	$self->{on_error}($self, $fatal, $message);
347	} else {	382	} elsif ($self->{fh}) {
348	Carp::croak "AnyEvent::Handle uncaught error: $!";	383	Carp::croak "AnyEvent::Handle uncaught error: $message";
349	}	384	}
350	}	385	}
351		386
352	=item $fh = $handle->fh	387	=item $fh = $handle->fh
353		388
…		…
390	}	425	}
391		426
392	=item $handle->autocork ($boolean)	427	=item $handle->autocork ($boolean)
393		428
394	Enables or disables the current autocork behaviour (see C<autocork>	429	Enables or disables the current autocork behaviour (see C<autocork>
395	constructor argument).	430	constructor argument). Changes will only take effect on the next write.
396		431
397	=cut	432	=cut
		433
		434	sub autocork {
		435	$_[0]{autocork} = $_[1];
		436	}
398		437
399	=item $handle->no_delay ($boolean)	438	=item $handle->no_delay ($boolean)
400		439
401	Enables or disables the C<no_delay> setting (see constructor argument of	440	Enables or disables the C<no_delay> setting (see constructor argument of
402	the same name for details).	441	the same name for details).
…		…
408		447
409	eval {	448	eval {
410	local $SIG{__DIE__};	449	local $SIG{__DIE__};
411	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];	450	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
412	};	451	};
		452	}
		453
		454	=item $handle->on_starttls ($cb)
		455
		456	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		457
		458	=cut
		459
		460	sub on_starttls {
		461	$_[0]{on_starttls} = $_[1];
		462	}
		463
		464	=item $handle->on_stoptls ($cb)
		465
		466	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		467
		468	=cut
		469
		470	sub on_starttls {
		471	$_[0]{on_stoptls} = $_[1];
413	}	472	}
414		473
415	#############################################################################	474	#############################################################################
416		475
417	=item $handle->timeout ($seconds)	476	=item $handle->timeout ($seconds)
…		…
495	my ($self, $cb) = @_;	554	my ($self, $cb) = @_;
496		555
497	$self->{on_drain} = $cb;	556	$self->{on_drain} = $cb;
498		557
499	$cb->($self)	558	$cb->($self)
500	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	559	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
501	}	560	}
502		561
503	=item $handle->push_write ($data)	562	=item $handle->push_write ($data)
504		563
505	Queues the given scalar to be written. You can push as much data as you	564	Queues the given scalar to be written. You can push as much data as you
…		…
522	substr $self->{wbuf}, 0, $len, "";	581	substr $self->{wbuf}, 0, $len, "";
523		582
524	$self->{_activity} = AnyEvent->now;	583	$self->{_activity} = AnyEvent->now;
525		584
526	$self->{on_drain}($self)	585	$self->{on_drain}($self)
527	if $self->{low_water_mark} >= length $self->{wbuf}	586	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
528	&& $self->{on_drain};	587	&& $self->{on_drain};
529		588
530	delete $self->{_ww} unless length $self->{wbuf};	589	delete $self->{_ww} unless length $self->{wbuf};
531	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {	590	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
532	$self->_error ($!, 1);	591	$self->_error ($!, 1);
…		…
556		615
557	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	616	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
558	->($self, @_);	617	->($self, @_);
559	}	618	}
560		619
561	if ($self->{filter_w}) {	620	if ($self->{tls}) {
562	$self->{filter_w}($self, \$_[0]);	621	$self->{_tls_wbuf} .= $_[0];
		622
		623	&_dotls ($self);
563	} else {	624	} else {
564	$self->{wbuf} .= $_[0];	625	$self->{wbuf} .= $_[0];
565	$self->_drain_wbuf;	626	$self->_drain_wbuf;
566	}	627	}
567	}	628	}
…		…
584	=cut	645	=cut
585		646
586	register_write_type netstring => sub {	647	register_write_type netstring => sub {
587	my ($self, $string) = @_;	648	my ($self, $string) = @_;
588		649
589	sprintf "%d:%s,", (length $string), $string	650	(length $string) . ":$string,"
590	};	651	};
591		652
592	=item packstring => $format, $data	653	=item packstring => $format, $data
593		654
594	An octet string prefixed with an encoded length. The encoding C<$format>	655	An octet string prefixed with an encoded length. The encoding C<$format>
…		…
659		720
660	pack "w/a*", Storable::nfreeze ($ref)	721	pack "w/a*", Storable::nfreeze ($ref)
661	};	722	};
662		723
663	=back	724	=back
		725
		726	=item $handle->push_shutdown
		727
		728	Sometimes you know you want to close the socket after writing your data
		729	before it was actually written. One way to do that is to replace your
		730	C<on_drain> handler by a callback that shuts down the socket (and set
		731	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		732	replaces the C<on_drain> callback with:
		733
		734	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		735
		736	This simply shuts down the write side and signals an EOF condition to the
		737	the peer.
		738
		739	You can rely on the normal read queue and C<on_eof> handling
		740	afterwards. This is the cleanest way to close a connection.
		741
		742	=cut
		743
		744	sub push_shutdown {
		745	my ($self) = @_;
		746
		747	delete $self->{low_water_mark};
		748	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		749	}
664		750
665	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)	751	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
666		752
667	This function (not method) lets you add your own types to C<push_write>.	753	This function (not method) lets you add your own types to C<push_write>.
668	Whenever the given C<type> is used, C<push_write> will invoke the code	754	Whenever the given C<type> is used, C<push_write> will invoke the code
…		…
772	) {	858	) {
773	$self->_error (&Errno::ENOSPC, 1), return;	859	$self->_error (&Errno::ENOSPC, 1), return;
774	}	860	}
775		861
776	while () {	862	while () {
		863	# we need to use a separate tls read buffer, as we must not receive data while
		864	# we are draining the buffer, and this can only happen with TLS.
		865	$self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
		866
777	my $len = length $self->{rbuf};	867	my $len = length $self->{rbuf};
778		868
779	if (my $cb = shift @{ $self->{_queue} }) {	869	if (my $cb = shift @{ $self->{_queue} }) {
780	unless ($cb->($self)) {	870	unless ($cb->($self)) {
781	if ($self->{_eof}) {	871	if ($self->{_eof}) {
…		…
803		893
804	last; # more data might arrive	894	last; # more data might arrive
805	}	895	}
806	} else {	896	} else {
807	# read side becomes idle	897	# read side becomes idle
808	delete $self->{_rw};	898	delete $self->{_rw} unless $self->{tls};
809	last;	899	last;
810	}	900	}
811	}	901	}
812		902
813	if ($self->{_eof}) {	903	if ($self->{_eof}) {
814	if ($self->{on_eof}) {	904	if ($self->{on_eof}) {
815	$self->{on_eof}($self)	905	$self->{on_eof}($self)
816	} else {	906	} else {
817	$self->_error (0, 1);	907	$self->_error (0, 1, "Unexpected end-of-file");
818	}	908	}
819	}	909	}
820		910
821	# may need to restart read watcher	911	# may need to restart read watcher
822	unless ($self->{_rw}) {	912	unless ($self->{_rw}) {
…		…
842		932
843	=item $handle->rbuf	933	=item $handle->rbuf
844		934
845	Returns the read buffer (as a modifiable lvalue).	935	Returns the read buffer (as a modifiable lvalue).
846		936
847	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	937	You can access the read buffer directly as the C<< ->{rbuf} >>
848	you want.	938	member, if you want. However, the only operation allowed on the
		939	read buffer (apart from looking at it) is removing data from its
		940	beginning. Otherwise modifying or appending to it is not allowed and will
		941	lead to hard-to-track-down bugs.
849		942
850	NOTE: The read buffer should only be used or modified if the C<on_read>,	943	NOTE: The read buffer should only be used or modified if the C<on_read>,
851	C<push_read> or C<unshift_read> methods are used. The other read methods	944	C<push_read> or C<unshift_read> methods are used. The other read methods
852	automatically manage the read buffer.	945	automatically manage the read buffer.
853		946
…		…
1108	An octet string prefixed with an encoded length. The encoding C<$format>	1201	An octet string prefixed with an encoded length. The encoding C<$format>
1109	uses the same format as a Perl C<pack> format, but must specify a single	1202	uses the same format as a Perl C<pack> format, but must specify a single
1110	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an	1203	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
1111	optional C<!>, C<< < >> or C<< > >> modifier).	1204	optional C<!>, C<< < >> or C<< > >> modifier).
1112		1205
1113	DNS over TCP uses a prefix of C<n>, EPP uses a prefix of C<N>.	1206	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1207	EPP uses a prefix of C<N> (4 octtes).
1114		1208
1115	Example: read a block of data prefixed by its length in BER-encoded	1209	Example: read a block of data prefixed by its length in BER-encoded
1116	format (very efficient).	1210	format (very efficient).
1117		1211
1118	$handle->push_read (packstring => "w", sub {	1212	$handle->push_read (packstring => "w", sub {
…		…
1148	}	1242	}
1149	};	1243	};
1150		1244
1151	=item json => $cb->($handle, $hash_or_arrayref)	1245	=item json => $cb->($handle, $hash_or_arrayref)
1152		1246
1153	Reads a JSON object or array, decodes it and passes it to the callback.	1247	Reads a JSON object or array, decodes it and passes it to the
		1248	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
1154		1249
1155	If a C<json> object was passed to the constructor, then that will be used	1250	If a C<json> object was passed to the constructor, then that will be used
1156	for the final decode, otherwise it will create a JSON coder expecting UTF-8.	1251	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
1157		1252
1158	This read type uses the incremental parser available with JSON version	1253	This read type uses the incremental parser available with JSON version
…		…
1167	=cut	1262	=cut
1168		1263
1169	register_read_type json => sub {	1264	register_read_type json => sub {
1170	my ($self, $cb) = @_;	1265	my ($self, $cb) = @_;
1171		1266
1172	require JSON;	1267	my $json = $self->{json} \|\|=
		1268	eval { require JSON::XS; JSON::XS->new->utf8 }
		1269	\|\| do { require JSON; JSON->new->utf8 };
1173		1270
1174	my $data;	1271	my $data;
1175	my $rbuf = \$self->{rbuf};	1272	my $rbuf = \$self->{rbuf};
1176		1273
1177	my $json = $self->{json} \|\|= JSON->new->utf8;
1178
1179	sub {	1274	sub {
1180	my $ref = $json->incr_parse ($self->{rbuf});	1275	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
1181		1276
1182	if ($ref) {	1277	if ($ref) {
1183	$self->{rbuf} = $json->incr_text;	1278	$self->{rbuf} = $json->incr_text;
1184	$json->incr_text = "";	1279	$json->incr_text = "";
1185	$cb->($self, $ref);	1280	$cb->($self, $ref);
1186		1281
1187	1	1282	1
		1283	} elsif ($@) {
		1284	# error case
		1285	$json->incr_skip;
		1286
		1287	$self->{rbuf} = $json->incr_text;
		1288	$json->incr_text = "";
		1289
		1290	$self->_error (&Errno::EBADMSG);
		1291
		1292	()
1188	} else {	1293	} else {
1189	$self->{rbuf} = "";	1294	$self->{rbuf} = "";
		1295
1190	()	1296	()
1191	}	1297	}
1192	}	1298	}
1193	};	1299	};
1194		1300
…		…
1271	Note that AnyEvent::Handle will automatically C<start_read> for you when	1377	Note that AnyEvent::Handle will automatically C<start_read> for you when
1272	you change the C<on_read> callback or push/unshift a read callback, and it	1378	you change the C<on_read> callback or push/unshift a read callback, and it
1273	will automatically C<stop_read> for you when neither C<on_read> is set nor	1379	will automatically C<stop_read> for you when neither C<on_read> is set nor
1274	there are any read requests in the queue.	1380	there are any read requests in the queue.
1275		1381
		1382	These methods will have no effect when in TLS mode (as TLS doesn't support
		1383	half-duplex connections).
		1384
1276	=cut	1385	=cut
1277		1386
1278	sub stop_read {	1387	sub stop_read {
1279	my ($self) = @_;	1388	my ($self) = @_;
1280		1389
1281	delete $self->{_rw};	1390	delete $self->{_rw} unless $self->{tls};
1282	}	1391	}
1283		1392
1284	sub start_read {	1393	sub start_read {
1285	my ($self) = @_;	1394	my ($self) = @_;
1286		1395
1287	unless ($self->{_rw} \|\| $self->{_eof}) {	1396	unless ($self->{_rw} \|\| $self->{_eof}) {
1288	Scalar::Util::weaken $self;	1397	Scalar::Util::weaken $self;
1289		1398
1290	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1399	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
1291	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1400	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1292	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} \|\| 8192, length $$rbuf;	1401	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} \|\| 8192, length $$rbuf;
1293		1402
1294	if ($len > 0) {	1403	if ($len > 0) {
1295	$self->{_activity} = AnyEvent->now;	1404	$self->{_activity} = AnyEvent->now;
1296		1405
1297	$self->{filter_r}	1406	if ($self->{tls}) {
1298	? $self->{filter_r}($self, $rbuf)	1407	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1299	: $self->{_in_drain} \|\| $self->_drain_rbuf;	1408
		1409	&_dotls ($self);
		1410	} else {
		1411	$self->_drain_rbuf unless $self->{_in_drain};
		1412	}
1300		1413
1301	} elsif (defined $len) {	1414	} elsif (defined $len) {
1302	delete $self->{_rw};	1415	delete $self->{_rw};
1303	$self->{_eof} = 1;	1416	$self->{_eof} = 1;
1304	$self->_drain_rbuf unless $self->{_in_drain};	1417	$self->_drain_rbuf unless $self->{_in_drain};
…		…
1308	}	1421	}
1309	});	1422	});
1310	}	1423	}
1311	}	1424	}
1312		1425
		1426	our $ERROR_SYSCALL;
		1427	our $ERROR_WANT_READ;
		1428
		1429	sub _tls_error {
		1430	my ($self, $err) = @_;
		1431
		1432	return $self->_error ($!, 1)
		1433	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1434
		1435	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1436
		1437	# reduce error string to look less scary
		1438	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1439
		1440	$self->_error (&Errno::EPROTO, 1, $err);
		1441	}
		1442
		1443	# poll the write BIO and send the data if applicable
		1444	# also decode read data if possible
		1445	# this is basiclaly our TLS state machine
		1446	# more efficient implementations are possible with openssl,
		1447	# but not with the buggy and incomplete Net::SSLeay.
1313	sub _dotls {	1448	sub _dotls {
1314	my ($self) = @_;	1449	my ($self) = @_;
1315		1450
1316	my $buf;	1451	my $tmp;
1317		1452
1318	if (length $self->{_tls_wbuf}) {	1453	if (length $self->{_tls_wbuf}) {
1319	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {	1454	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
1320	substr $self->{_tls_wbuf}, 0, $len, "";	1455	substr $self->{_tls_wbuf}, 0, $tmp, "";
1321	}	1456	}
1322	}
1323		1457
		1458	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1459	return $self->_tls_error ($tmp)
		1460	if $tmp != $ERROR_WANT_READ
		1461	&& ($tmp != $ERROR_SYSCALL \|\| $!);
		1462	}
		1463
		1464	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1465	unless (length $tmp) {
		1466	&_freetls;
		1467	if ($self->{on_stoptls}) {
		1468	$self->{on_stoptls}($self);
		1469	return;
		1470	} else {
		1471	# let's treat SSL-eof as we treat normal EOF
		1472	delete $self->{_rw};
		1473	$self->{_eof} = 1;
		1474	}
		1475	}
		1476
		1477	$self->{_tls_rbuf} .= $tmp;
		1478	$self->_drain_rbuf unless $self->{_in_drain};
		1479	$self->{tls} or return; # tls session might have gone away in callback
		1480	}
		1481
		1482	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1483	return $self->_tls_error ($tmp)
		1484	if $tmp != $ERROR_WANT_READ
		1485	&& ($tmp != $ERROR_SYSCALL \|\| $!);
		1486
1324	if (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {	1487	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1325	$self->{wbuf} .= $buf;	1488	$self->{wbuf} .= $tmp;
1326	$self->_drain_wbuf;	1489	$self->_drain_wbuf;
1327	}	1490	}
1328		1491
1329	while (defined ($buf = Net::SSLeay::read ($self->{tls}))) {	1492	$self->{_on_starttls}
1330	if (length $buf) {	1493	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
1331	$self->{rbuf} .= $buf;	1494	and (delete $self->{_on_starttls})->($self, 1);
1332	$self->_drain_rbuf unless $self->{_in_drain};
1333	} else {
1334	# let's treat SSL-eof as we treat normal EOF
1335	$self->{_eof} = 1;
1336	$self->_shutdown;
1337	return;
1338	}
1339	}
1340
1341	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
1342
1343	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
1344	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
1345	return $self->_error ($!, 1);
1346	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
1347	return $self->_error (&Errno::EIO, 1);
1348	}
1349
1350	# all others are fine for our purposes
1351	}
1352	}	1495	}
1353		1496
1354	=item $handle->starttls ($tls[, $tls_ctx])	1497	=item $handle->starttls ($tls[, $tls_ctx])
1355		1498
1356	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1499	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
…		…
1358	C<starttls>.	1501	C<starttls>.
1359		1502
1360	The first argument is the same as the C<tls> constructor argument (either	1503	The first argument is the same as the C<tls> constructor argument (either
1361	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1504	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
1362		1505
1363	The second argument is the optional C<Net::SSLeay::CTX> object that is	1506	The second argument is the optional C<AnyEvent::TLS> object that is used
1364	used when AnyEvent::Handle has to create its own TLS connection object.	1507	when AnyEvent::Handle has to create its own TLS connection object, or
		1508	a hash reference with C<< key => value >> pairs that will be used to
		1509	construct a new context.
1365		1510
1366	The TLS connection object will end up in C<< $handle->{tls} >> after this	1511	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
1367	call and can be used or changed to your liking. Note that the handshake	1512	context in C<< $handle->{tls_ctx} >> after this call and can be used or
1368	might have already started when this function returns.	1513	changed to your liking. Note that the handshake might have already started
		1514	when this function returns.
1369		1515
		1516	If it an error to start a TLS handshake more than once per
		1517	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1518
1370	=cut	1519	=cut
		1520
		1521	our %TLS_CACHE; #TODO not yet documented, should we?
1371		1522
1372	sub starttls {	1523	sub starttls {
1373	my ($self, $ssl, $ctx) = @_;	1524	my ($self, $ssl, $ctx) = @_;
1374		1525
1375	$self->stoptls;	1526	require Net::SSLeay;
1376		1527
1377	if ($ssl eq "accept") {	1528	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
1378	$ssl = Net::SSLeay::new ($ctx \|\| TLS_CTX ());	1529	if $self->{tls};
1379	Net::SSLeay::set_accept_state ($ssl);	1530
1380	} elsif ($ssl eq "connect") {	1531	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
1381	$ssl = Net::SSLeay::new ($ctx \|\| TLS_CTX ());	1532	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
1382	Net::SSLeay::set_connect_state ($ssl);	1533
		1534	$ctx \|\|= $self->{tls_ctx};
		1535
		1536	if ("HASH" eq ref $ctx) {
		1537	require AnyEvent::TLS;
		1538
		1539	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context
		1540
		1541	if ($ctx->{cache}) {
		1542	my $key = $ctx+0;
		1543	$ctx = $TLS_CACHE{$key} \|\|= new AnyEvent::TLS %$ctx;
		1544	} else {
		1545	$ctx = new AnyEvent::TLS %$ctx;
		1546	}
		1547	}
1383	}	1548
1384		1549	$self->{tls_ctx} = $ctx \|\| TLS_CTX ();
1385	$self->{tls} = $ssl;	1550	$self->{tls} = $ssl = $self->{tls_ctx}->_get_session ($ssl, $self, $self->{peername});
1386		1551
1387	# basically, this is deep magic (because SSL_read should have the same issues)	1552	# basically, this is deep magic (because SSL_read should have the same issues)
1388	# but the openssl maintainers basically said: "trust us, it just works".	1553	# but the openssl maintainers basically said: "trust us, it just works".
1389	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1554	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
1390	# and mismaintained ssleay-module doesn't even offer them).	1555	# and mismaintained ssleay-module doesn't even offer them).
1391	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1556	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
1392	#	1557	#
1393	# in short: this is a mess.	1558	# in short: this is a mess.
1394	#	1559	#
1395	# note that we do not try to kepe the length constant between writes as we are required to do.	1560	# note that we do not try to keep the length constant between writes as we are required to do.
1396	# we assume that most (but not all) of this insanity only applies to non-blocking cases,	1561	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
1397	# and we drive openssl fully in blocking mode here.	1562	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1563	# have identity issues in that area.
1398	Net::SSLeay::CTX_set_mode ($self->{tls},	1564	# Net::SSLeay::CTX_set_mode ($ssl,
1399	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } \|\| 1)	1565	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } \|\| 1)
1400	\| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } \|\| 2));	1566	# \| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } \|\| 2));
		1567	Net::SSLeay::CTX_set_mode ($ssl, 1\|2);
1401		1568
1402	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1569	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1403	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1570	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1404		1571
1405	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});	1572	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
1406		1573
1407	$self->{filter_w} = sub {	1574	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
1408	$_[0]{_tls_wbuf} .= ${$_[1]};	1575	if exists $self->{on_starttls};
1409	&_dotls;	1576
1410	};	1577	&_dotls; # need to trigger the initial handshake
1411	$self->{filter_r} = sub {	1578	$self->start_read; # make sure we actually do read
1412	Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
1413	&_dotls;
1414	};
1415	}	1579	}
1416		1580
1417	=item $handle->stoptls	1581	=item $handle->stoptls
1418		1582
1419	Destroys the SSL connection, if any. Partial read or write data will be	1583	Shuts down the SSL connection - this makes a proper EOF handshake by
1420	lost.	1584	sending a close notify to the other side, but since OpenSSL doesn't
		1585	support non-blocking shut downs, it is not possible to re-use the stream
		1586	afterwards.
1421		1587
1422	=cut	1588	=cut
1423		1589
1424	sub stoptls {	1590	sub stoptls {
1425	my ($self) = @_;	1591	my ($self) = @_;
1426		1592
1427	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	1593	if ($self->{tls}) {
		1594	Net::SSLeay::shutdown ($self->{tls});
1428		1595
1429	delete $self->{_rbio};	1596	&_dotls;
1430	delete $self->{_wbio};	1597
1431	delete $self->{_tls_wbuf};	1598	# # we don't give a shit. no, we do, but we can't. no...#d#
1432	delete $self->{filter_r};	1599	# # we, we... have to use openssl :/#d#
1433	delete $self->{filter_w};	1600	# &_freetls;#d#
		1601	}
		1602	}
		1603
		1604	sub _freetls {
		1605	my ($self) = @_;
		1606
		1607	return unless $self->{tls};
		1608
		1609	$self->{_on_starttls}
		1610	and (delete $self->{_on_starttls})->($self, undef);
		1611
		1612	$self->{tls_ctx}->_put_session (delete $self->{tls});
		1613
		1614	delete @$self{qw(_rbio _wbio _tls_wbuf)};
1434	}	1615	}
1435		1616
1436	sub DESTROY {	1617	sub DESTROY {
1437	my $self = shift;	1618	my ($self) = @_;
1438		1619
1439	$self->stoptls;	1620	&_freetls;
1440		1621
1441	my $linger = exists $self->{linger} ? $self->{linger} : 3600;	1622	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
1442		1623
1443	if ($linger && length $self->{wbuf}) {	1624	if ($linger && length $self->{wbuf}) {
1444	my $fh = delete $self->{fh};	1625	my $fh = delete $self->{fh};
…		…
1459	@linger = ();	1640	@linger = ();
1460	});	1641	});
1461	}	1642	}
1462	}	1643	}
1463		1644
		1645	=item $handle->destroy
		1646
		1647	Shuts down the handle object as much as possible - this call ensures that
		1648	no further callbacks will be invoked and as many resources as possible
		1649	will be freed. You must not call any methods on the object afterwards.
		1650
		1651	Normally, you can just "forget" any references to an AnyEvent::Handle
		1652	object and it will simply shut down. This works in fatal error and EOF
		1653	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1654	callback, so when you want to destroy the AnyEvent::Handle object from
		1655	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1656	that case.
		1657
		1658	The handle might still linger in the background and write out remaining
		1659	data, as specified by the C<linger> option, however.
		1660
		1661	=cut
		1662
		1663	sub destroy {
		1664	my ($self) = @_;
		1665
		1666	$self->DESTROY;
		1667	%$self = ();
		1668	}
		1669
1464	=item AnyEvent::Handle::TLS_CTX	1670	=item AnyEvent::Handle::TLS_CTX
1465		1671
1466	This function creates and returns the Net::SSLeay::CTX object used by	1672	This function creates and returns the AnyEvent::TLS object used by default
1467	default for TLS mode.	1673	for TLS mode.
1468		1674
1469	The context is created like this:	1675	The context is created by calling L<AnyEvent::TLS> without any arguments.
1470
1471	Net::SSLeay::load_error_strings;
1472	Net::SSLeay::SSLeay_add_ssl_algorithms;
1473	Net::SSLeay::randomize;
1474
1475	my $CTX = Net::SSLeay::CTX_new;
1476
1477	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
1478		1676
1479	=cut	1677	=cut
1480		1678
1481	our $TLS_CTX;	1679	our $TLS_CTX;
1482		1680
1483	sub TLS_CTX() {	1681	sub TLS_CTX() {
1484	$TLS_CTX \|\| do {	1682	$TLS_CTX \|\|= do {
1485	require Net::SSLeay;	1683	require AnyEvent::TLS;
1486		1684
1487	Net::SSLeay::load_error_strings ();	1685	new AnyEvent::TLS
1488	Net::SSLeay::SSLeay_add_ssl_algorithms ();
1489	Net::SSLeay::randomize ();
1490
1491	$TLS_CTX = Net::SSLeay::CTX_new ();
1492
1493	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
1494
1495	$TLS_CTX
1496	}	1686	}
1497	}	1687	}
1498		1688
1499	=back	1689	=back
		1690
		1691
		1692	=head1 NONFREQUENTLY ASKED QUESTIONS
		1693
		1694	=over 4
		1695
		1696	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1697	still get further invocations!
		1698
		1699	That's because AnyEvent::Handle keeps a reference to itself when handling
		1700	read or write callbacks.
		1701
		1702	It is only safe to "forget" the reference inside EOF or error callbacks,
		1703	from within all other callbacks, you need to explicitly call the C<<
		1704	->destroy >> method.
		1705
		1706	=item I get different callback invocations in TLS mode/Why can't I pause
		1707	reading?
		1708
		1709	Unlike, say, TCP, TLS connections do not consist of two independent
		1710	communication channels, one for each direction. Or put differently. The
		1711	read and write directions are not independent of each other: you cannot
		1712	write data unless you are also prepared to read, and vice versa.
		1713
		1714	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1715	callback invocations when you are not expecting any read data - the reason
		1716	is that AnyEvent::Handle always reads in TLS mode.
		1717
		1718	During the connection, you have to make sure that you always have a
		1719	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1720	connection (or when you no longer want to use it) you can call the
		1721	C<destroy> method.
		1722
		1723	=item How do I read data until the other side closes the connection?
		1724
		1725	If you just want to read your data into a perl scalar, the easiest way
		1726	to achieve this is by setting an C<on_read> callback that does nothing,
		1727	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1728	will be in C<$_[0]{rbuf}>:
		1729
		1730	$handle->on_read (sub { });
		1731	$handle->on_eof (undef);
		1732	$handle->on_error (sub {
		1733	my $data = delete $_[0]{rbuf};
		1734	undef $handle;
		1735	});
		1736
		1737	The reason to use C<on_error> is that TCP connections, due to latencies
		1738	and packets loss, might get closed quite violently with an error, when in
		1739	fact, all data has been received.
		1740
		1741	It is usually better to use acknowledgements when transferring data,
		1742	to make sure the other side hasn't just died and you got the data
		1743	intact. This is also one reason why so many internet protocols have an
		1744	explicit QUIT command.
		1745
		1746	=item I don't want to destroy the handle too early - how do I wait until
		1747	all data has been written?
		1748
		1749	After writing your last bits of data, set the C<on_drain> callback
		1750	and destroy the handle in there - with the default setting of
		1751	C<low_water_mark> this will be called precisely when all data has been
		1752	written to the socket:
		1753
		1754	$handle->push_write (...);
		1755	$handle->on_drain (sub {
		1756	warn "all data submitted to the kernel\n";
		1757	undef $handle;
		1758	});
		1759
		1760	=back
		1761
1500		1762
1501	=head1 SUBCLASSING AnyEvent::Handle	1763	=head1 SUBCLASSING AnyEvent::Handle
1502		1764
1503	In many cases, you might want to subclass AnyEvent::Handle.	1765	In many cases, you might want to subclass AnyEvent::Handle.
1504		1766

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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents): Revision 1.90 by root, Mon Sep 29 02:08:57 2008 UTC vs. Revision 1.142 by root, Mon Jul 6 20:24:47 2009 UTC

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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.90 by root, Mon Sep 29 02:08:57 2008 UTC vs.
Revision 1.142 by root, Mon Jul 6 20:24:47 2009 UTC