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Revision 1.9 by root, Fri May 2 16:07:46 2008 UTC vs.
Revision 1.158 by root, Fri Jul 24 08:40:35 2009 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	no warnings;
4	use strict;
5
6	use AnyEvent ();
7	use AnyEvent::Util ();
8	use Scalar::Util ();	3	use Scalar::Util ();
9	use Carp ();	4	use Carp ();
10	use Fcntl ();
11	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);
12		9
13	=head1 NAME	10	=head1 NAME
14		11
15	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	12	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
16		13
17	=cut	14	=cut
18		15
19	our $VERSION = '0.02';	16	our $VERSION = 4.86;
20		17
21	=head1 SYNOPSIS	18	=head1 SYNOPSIS
22		19
23	use AnyEvent;	20	use AnyEvent;
24	use AnyEvent::Handle;	21	use AnyEvent::Handle;
25		22
26	my $cv = AnyEvent->condvar;	23	my $cv = AnyEvent->condvar;
27		24
28	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	25	my $hdl; $hdl = new AnyEvent::Handle
29
30	#TODO
31
32	# or use the constructor to pass the callback:
33
34	my $ae_fh2 =
35	AnyEvent::Handle->new (
36	fh => \*STDIN,	26	fh => \*STDIN,
37	on_eof => sub {	27	on_error => sub {
38	$cv->broadcast;	28	my ($hdl, $fatal, $msg) = @_;
39	},	29	warn "got error $msg\n";
40	#TODO	30	$hdl->destroy;
		31	$cv->send;
41	);	32	);
42		33
43	$cv->wait;	34	# send some request line
		35	$hdl->push_write ("getinfo\015\012");
		36
		37	# read the response line
		38	$hdl->push_read (line => sub {
		39	my ($hdl, $line) = @_;
		40	warn "got line <$line>\n";
		41	$cv->send;
		42	});
		43
		44	$cv->recv;
44		45
45	=head1 DESCRIPTION	46	=head1 DESCRIPTION
46		47
47	This module is a helper module to make it easier to do event-based I/O on	48	This module is a helper module to make it easier to do event-based I/O on
48	filehandles (and sockets, see L<AnyEvent::Socket> for an easy way to make	49	filehandles. For utility functions for doing non-blocking connects and accepts
49	non-blocking resolves and connects).	50	on sockets see L<AnyEvent::Util>.
		51
		52	The L<AnyEvent::Intro> tutorial contains some well-documented
		53	AnyEvent::Handle examples.
50		54
51	In the following, when the documentation refers to of "bytes" then this	55	In the following, when the documentation refers to of "bytes" then this
52	means characters. As sysread and syswrite are used for all I/O, their	56	means characters. As sysread and syswrite are used for all I/O, their
53	treatment of characters applies to this module as well.	57	treatment of characters applies to this module as well.
54		58
…		…
57		61
58	=head1 METHODS	62	=head1 METHODS
59		63
60	=over 4	64	=over 4
61		65
62	=item B<new (%args)>	66	=item $handle = B<new> AnyEvent::TLS fh => $filehandle, key => value...
63		67
64	The constructor supports these arguments (all as key => value pairs).	68	The constructor supports these arguments (all as C<< key => value >> pairs).
65		69
66	=over 4	70	=over 4
67		71
68	=item fh => $filehandle [MANDATORY]	72	=item fh => $filehandle [MANDATORY]
69		73
		74	#=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
		75
70	The filehandle this L<AnyEvent::Handle> object will operate on.	76	The filehandle this L<AnyEvent::Handle> object will operate on.
71
72	NOTE: The filehandle will be set to non-blocking (using	77	NOTE: The filehandle will be set to non-blocking mode (using
73	AnyEvent::Util::fh_nonblocking).	78	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		79	that mode.
74		80
75	=item on_error => $cb->($self) [MANDATORY]	81	#=item connect => [$host, $service]
		82	#
		83	# You have to specify either this parameter, or C<connect>, below.
		84	#Try to connect to the specified host and service (port), using
		85	#C<AnyEvent::Socket::tcp_connect>.
		86	#
		87	#When this
76		88
77	This is the fatal error callback, that is called when a fatal error ocurs,	89	=item on_eof => $cb->($handle)
		90
		91	Set the callback to be called when an end-of-file condition is detected,
		92	i.e. in the case of a socket, when the other side has closed the
		93	connection cleanly, and there are no outstanding read requests in the
		94	queue (if there are read requests, then an EOF counts as an unexpected
		95	connection close and will be flagged as an error).
		96
		97	For sockets, this just means that the other side has stopped sending data,
		98	you can still try to write data, and, in fact, one can return from the EOF
		99	callback and continue writing data, as only the read part has been shut
		100	down.
		101
		102	If an EOF condition has been detected but no C<on_eof> callback has been
		103	set, then a fatal error will be raised with C<$!> set to <0>.
		104
		105	=item on_error => $cb->($handle, $fatal, $message)
		106
		107	This is the error callback, which is called when, well, some error
78	such as not being able to resolve the hostname, failure to connect or a	108	occured, such as not being able to resolve the hostname, failure to
79	read error.	109	connect or a read error.
80		110
81	The object will not be in a usable state when this callback has been	111	Some errors are fatal (which is indicated by C<$fatal> being true). On
82	called.	112	fatal errors the handle object will be destroyed (by a call to C<< ->
		113	destroy >>) after invoking the error callback (which means you are free to
		114	examine the handle object). Examples of fatal errors are an EOF condition
		115	with active (but unsatisifable) read watchers (C<EPIPE>) or I/O errors.
83		116
		117	AnyEvent::Handle tries to find an appropriate error code for you to check
		118	against, but in some cases (TLS errors), this does not work well. It is
		119	recommended to always output the C<$message> argument in human-readable
		120	error messages (it's usually the same as C<"$!">).
		121
		122	Non-fatal errors can be retried by simply returning, but it is recommended
		123	to simply ignore this parameter and instead abondon the handle object
		124	when this callback is invoked. Examples of non-fatal errors are timeouts
		125	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		126
84	On callback entrance, the value of C<$!> contains the opertaing system	127	On callback entrance, the value of C<$!> contains the operating system
85	error (or C<ENOSPC> or C<EPIPE>).	128	error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		129	C<EPROTO>).
86		130
87	=item on_eof => $cb->($self) [MANDATORY]	131	While not mandatory, it is I<highly> recommended to set this callback, as
		132	you will not be notified of errors otherwise. The default simply calls
		133	C<croak>.
88		134
89	Set the callback to be called on EOF.
90
91	=item on_read => $cb->($self)	135	=item on_read => $cb->($handle)
92		136
93	This sets the default read callback, which is called when data arrives	137	This sets the default read callback, which is called when data arrives
94	and no read request is in the queue. If the read callback is C<undef>	138	and no read request is in the queue (unlike read queue callbacks, this
95	or has never been set, than AnyEvent::Handle will cease reading from the	139	callback will only be called when at least one octet of data is in the
96	filehandle.	140	read buffer).
97		141
98	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	142	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
99	method or acces sthe C<$self->{rbuf}> member directly.	143	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		144	must not enlarge or modify the read buffer, you can only remove data at
		145	the beginning from it.
100		146
101	When an EOF condition is detected then AnyEvent::Handle will first try to	147	When an EOF condition is detected then AnyEvent::Handle will first try to
102	feed all the remaining data to the queued callbacks and C<on_read> before	148	feed all the remaining data to the queued callbacks and C<on_read> before
103	calling the C<on_eof> callback. If no progress can be made, then a fatal	149	calling the C<on_eof> callback. If no progress can be made, then a fatal
104	error will be raised (with C<$!> set to C<EPIPE>).	150	error will be raised (with C<$!> set to C<EPIPE>).
105		151
		152	Note that, unlike requests in the read queue, an C<on_read> callback
		153	doesn't mean you I<require> some data: if there is an EOF and there
		154	are outstanding read requests then an error will be flagged. With an
		155	C<on_read> callback, the C<on_eof> callback will be invoked.
		156
106	=item on_drain => $cb->()	157	=item on_drain => $cb->($handle)
107		158
108	This sets the callback that is called when the write buffer becomes empty	159	This sets the callback that is called when the write buffer becomes empty
109	(or when the callback is set and the buffer is empty already).	160	(or when the callback is set and the buffer is empty already).
110		161
111	To append to the write buffer, use the C<< ->push_write >> method.	162	To append to the write buffer, use the C<< ->push_write >> method.
112		163
		164	This callback is useful when you don't want to put all of your write data
		165	into the queue at once, for example, when you want to write the contents
		166	of some file to the socket you might not want to read the whole file into
		167	memory and push it into the queue, but instead only read more data from
		168	the file when the write queue becomes empty.
		169
		170	=item timeout => $fractional_seconds
		171
		172	If non-zero, then this enables an "inactivity" timeout: whenever this many
		173	seconds pass without a successful read or write on the underlying file
		174	handle, the C<on_timeout> callback will be invoked (and if that one is
		175	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		176
		177	Note that timeout processing is also active when you currently do not have
		178	any outstanding read or write requests: If you plan to keep the connection
		179	idle then you should disable the timout temporarily or ignore the timeout
		180	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		181	restart the timeout.
		182
		183	Zero (the default) disables this timeout.
		184
		185	=item on_timeout => $cb->($handle)
		186
		187	Called whenever the inactivity timeout passes. If you return from this
		188	callback, then the timeout will be reset as if some activity had happened,
		189	so this condition is not fatal in any way.
		190
113	=item rbuf_max => <bytes>	191	=item rbuf_max => <bytes>
114		192
115	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	193	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
116	when the read buffer ever (strictly) exceeds this size. This is useful to	194	when the read buffer ever (strictly) exceeds this size. This is useful to
117	avoid denial-of-service attacks.	195	avoid some forms of denial-of-service attacks.
118		196
119	For example, a server accepting connections from untrusted sources should	197	For example, a server accepting connections from untrusted sources should
120	be configured to accept only so-and-so much data that it cannot act on	198	be configured to accept only so-and-so much data that it cannot act on
121	(for example, when expecting a line, an attacker could send an unlimited	199	(for example, when expecting a line, an attacker could send an unlimited
122	amount of data without a callback ever being called as long as the line	200	amount of data without a callback ever being called as long as the line
123	isn't finished).	201	isn't finished).
124		202
		203	=item autocork => <boolean>
		204
		205	When disabled (the default), then C<push_write> will try to immediately
		206	write the data to the handle, if possible. This avoids having to register
		207	a write watcher and wait for the next event loop iteration, but can
		208	be inefficient if you write multiple small chunks (on the wire, this
		209	disadvantage is usually avoided by your kernel's nagle algorithm, see
		210	C<no_delay>, but this option can save costly syscalls).
		211
		212	When enabled, then writes will always be queued till the next event loop
		213	iteration. This is efficient when you do many small writes per iteration,
		214	but less efficient when you do a single write only per iteration (or when
		215	the write buffer often is full). It also increases write latency.
		216
		217	=item no_delay => <boolean>
		218
		219	When doing small writes on sockets, your operating system kernel might
		220	wait a bit for more data before actually sending it out. This is called
		221	the Nagle algorithm, and usually it is beneficial.
		222
		223	In some situations you want as low a delay as possible, which can be
		224	accomplishd by setting this option to a true value.
		225
		226	The default is your opertaing system's default behaviour (most likely
		227	enabled), this option explicitly enables or disables it, if possible.
		228
125	=item read_size => <bytes>	229	=item read_size => <bytes>
126		230
127	The default read block size (the amount of bytes this module will try to read	231	The default read block size (the amount of bytes this module will
128	on each [loop iteration). Default: C<4096>.	232	try to read during each loop iteration, which affects memory
		233	requirements). Default: C<8192>.
129		234
130	=item low_water_mark => <bytes>	235	=item low_water_mark => <bytes>
131		236
132	Sets the amount of bytes (default: C<0>) that make up an "empty" write	237	Sets the amount of bytes (default: C<0>) that make up an "empty" write
133	buffer: If the write reaches this size or gets even samller it is	238	buffer: If the write reaches this size or gets even samller it is
134	considered empty.	239	considered empty.
135		240
		241	Sometimes it can be beneficial (for performance reasons) to add data to
		242	the write buffer before it is fully drained, but this is a rare case, as
		243	the operating system kernel usually buffers data as well, so the default
		244	is good in almost all cases.
		245
		246	=item linger => <seconds>
		247
		248	If non-zero (default: C<3600>), then the destructor of the
		249	AnyEvent::Handle object will check whether there is still outstanding
		250	write data and will install a watcher that will write this data to the
		251	socket. No errors will be reported (this mostly matches how the operating
		252	system treats outstanding data at socket close time).
		253
		254	This will not work for partial TLS data that could not be encoded
		255	yet. This data will be lost. Calling the C<stoptls> method in time might
		256	help.
		257
		258	=item peername => $string
		259
		260	A string used to identify the remote site - usually the DNS hostname
		261	(I<not> IDN!) used to create the connection, rarely the IP address.
		262
		263	Apart from being useful in error messages, this string is also used in TLS
		264	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		265	verification will be skipped when C<peername> is not specified or
		266	C<undef>.
		267
		268	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		269
		270	When this parameter is given, it enables TLS (SSL) mode, that means
		271	AnyEvent will start a TLS handshake as soon as the conenction has been
		272	established and will transparently encrypt/decrypt data afterwards.
		273
		274	All TLS protocol errors will be signalled as C<EPROTO>, with an
		275	appropriate error message.
		276
		277	TLS mode requires Net::SSLeay to be installed (it will be loaded
		278	automatically when you try to create a TLS handle): this module doesn't
		279	have a dependency on that module, so if your module requires it, you have
		280	to add the dependency yourself.
		281
		282	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		283	C<accept>, and for the TLS client side of a connection, use C<connect>
		284	mode.
		285
		286	You can also provide your own TLS connection object, but you have
		287	to make sure that you call either C<Net::SSLeay::set_connect_state>
		288	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		289	AnyEvent::Handle. Also, this module will take ownership of this connection
		290	object.
		291
		292	At some future point, AnyEvent::Handle might switch to another TLS
		293	implementation, then the option to use your own session object will go
		294	away.
		295
		296	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		297	passing in the wrong integer will lead to certain crash. This most often
		298	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		299	segmentation fault.
		300
		301	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		302
		303	=item tls_ctx => $anyevent_tls
		304
		305	Use the given C<AnyEvent::TLS> object to create the new TLS connection
		306	(unless a connection object was specified directly). If this parameter is
		307	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		308
		309	Instead of an object, you can also specify a hash reference with C<< key
		310	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		311	new TLS context object.
		312
		313	=item on_starttls => $cb->($handle, $success[, $error_message])
		314
		315	This callback will be invoked when the TLS/SSL handshake has finished. If
		316	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		317	(C<on_stoptls> will not be called in this case).
		318
		319	The session in C<< $handle->{tls} >> can still be examined in this
		320	callback, even when the handshake was not successful.
		321
		322	TLS handshake failures will not cause C<on_error> to be invoked when this
		323	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		324
		325	Without this callback, handshake failures lead to C<on_error> being
		326	called, as normal.
		327
		328	Note that you cannot call C<starttls> right again in this callback. If you
		329	need to do that, start an zero-second timer instead whose callback can
		330	then call C<< ->starttls >> again.
		331
		332	=item on_stoptls => $cb->($handle)
		333
		334	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		335	set, then it will be invoked after freeing the TLS session. If it is not,
		336	then a TLS shutdown condition will be treated like a normal EOF condition
		337	on the handle.
		338
		339	The session in C<< $handle->{tls} >> can still be examined in this
		340	callback.
		341
		342	This callback will only be called on TLS shutdowns, not when the
		343	underlying handle signals EOF.
		344
		345	=item json => JSON or JSON::XS object
		346
		347	This is the json coder object used by the C<json> read and write types.
		348
		349	If you don't supply it, then AnyEvent::Handle will create and use a
		350	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		351	texts.
		352
		353	Note that you are responsible to depend on the JSON module if you want to
		354	use this functionality, as AnyEvent does not have a dependency itself.
		355
136	=back	356	=back
137		357
138	=cut	358	=cut
139		359
140	sub new {	360	sub new {
141	my $class = shift;	361	my $class = shift;
142
143	my $self = bless { @_ }, $class;	362	my $self = bless { @_ }, $class;
144		363
145	$self->{fh} or Carp::croak "mandatory argument fh is missing";	364	$self->{fh} or Carp::croak "mandatory argument fh is missing";
146		365
147	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	366	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
148		367
149	$self->on_error ((delete $self->{on_error}) or Carp::croak "mandatory argument on_error is missing");	368	$self->{_activity} = AnyEvent->now;
150	$self->on_eof ((delete $self->{on_eof} ) or Carp::croak "mandatory argument on_eof is missing");	369	$self->_timeout;
		370
		371	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		372
		373	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		374	if $self->{tls};
151		375
152	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	376	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};
153	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
154		377
155	$self	378	$self->start_read
156	}	379	if $self->{on_read};
157		380
		381	$self->{fh} && $self
		382	}
		383
158	sub _shutdown {	384	#sub _shutdown {
159	my ($self) = @_;	385	# my ($self) = @_;
		386	#
		387	# delete @$self{qw(_tw _rw _ww fh wbuf on_read _queue)};
		388	# $self->{_eof} = 1; # tell starttls et. al to stop trying
		389	#
		390	# &_freetls;
		391	#}
160		392
161	delete $self->{rw};
162	delete $self->{ww};
163	delete $self->{fh};
164	}
165
166	sub error {	393	sub _error {
167	my ($self) = @_;	394	my ($self, $errno, $fatal, $message) = @_;
168		395
169	{	396	$! = $errno;
170	local $!;	397	$message ||= "$!";
		398
		399	if ($self->{on_error}) {
		400	$self->{on_error}($self, $fatal, $message);
		401	$self->destroy if $fatal;
		402	} elsif ($self->{fh}) {
171	$self->_shutdown;	403	$self->destroy;
		404	Carp::croak "AnyEvent::Handle uncaught error: $message";
172	}	405	}
173
174	$self->{on_error}($self);
175	}	406	}
176		407
177	=item $fh = $handle->fh	408	=item $fh = $handle->fh
178		409
179	This method returns the filehandle of the L<AnyEvent::Handle> object.	410	This method returns the file handle used to create the L<AnyEvent::Handle> object.
180		411
181	=cut	412	=cut
182		413
183	sub fh { $_[0]->{fh} }	414	sub fh { $_[0]{fh} }
184		415
185	=item $handle->on_error ($cb)	416	=item $handle->on_error ($cb)
186		417
187	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	418	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
188		419
…		…
200		431
201	sub on_eof {	432	sub on_eof {
202	$_[0]{on_eof} = $_[1];	433	$_[0]{on_eof} = $_[1];
203	}	434	}
204		435
		436	=item $handle->on_timeout ($cb)
		437
		438	Replace the current C<on_timeout> callback, or disables the callback (but
		439	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		440	argument and method.
		441
		442	=cut
		443
		444	sub on_timeout {
		445	$_[0]{on_timeout} = $_[1];
		446	}
		447
		448	=item $handle->autocork ($boolean)
		449
		450	Enables or disables the current autocork behaviour (see C<autocork>
		451	constructor argument). Changes will only take effect on the next write.
		452
		453	=cut
		454
		455	sub autocork {
		456	$_[0]{autocork} = $_[1];
		457	}
		458
		459	=item $handle->no_delay ($boolean)
		460
		461	Enables or disables the C<no_delay> setting (see constructor argument of
		462	the same name for details).
		463
		464	=cut
		465
		466	sub no_delay {
		467	$_[0]{no_delay} = $_[1];
		468
		469	eval {
		470	local $SIG{__DIE__};
		471	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		472	};
		473	}
		474
		475	=item $handle->on_starttls ($cb)
		476
		477	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		478
		479	=cut
		480
		481	sub on_starttls {
		482	$_[0]{on_starttls} = $_[1];
		483	}
		484
		485	=item $handle->on_stoptls ($cb)
		486
		487	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		488
		489	=cut
		490
		491	sub on_starttls {
		492	$_[0]{on_stoptls} = $_[1];
		493	}
		494
		495	#############################################################################
		496
		497	=item $handle->timeout ($seconds)
		498
		499	Configures (or disables) the inactivity timeout.
		500
		501	=cut
		502
		503	sub timeout {
		504	my ($self, $timeout) = @_;
		505
		506	$self->{timeout} = $timeout;
		507	$self->_timeout;
		508	}
		509
		510	# reset the timeout watcher, as neccessary
		511	# also check for time-outs
		512	sub _timeout {
		513	my ($self) = @_;
		514
		515	if ($self->{timeout}) {
		516	my $NOW = AnyEvent->now;
		517
		518	# when would the timeout trigger?
		519	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		520
		521	# now or in the past already?
		522	if ($after <= 0) {
		523	$self->{_activity} = $NOW;
		524
		525	if ($self->{on_timeout}) {
		526	$self->{on_timeout}($self);
		527	} else {
		528	$self->_error (Errno::ETIMEDOUT);
		529	}
		530
		531	# callback could have changed timeout value, optimise
		532	return unless $self->{timeout};
		533
		534	# calculate new after
		535	$after = $self->{timeout};
		536	}
		537
		538	Scalar::Util::weaken $self;
		539	return unless $self; # ->error could have destroyed $self
		540
		541	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		542	delete $self->{_tw};
		543	$self->_timeout;
		544	});
		545	} else {
		546	delete $self->{_tw};
		547	}
		548	}
		549
205	#############################################################################	550	#############################################################################
206		551
207	=back	552	=back
208		553
209	=head2 WRITE QUEUE	554	=head2 WRITE QUEUE
…		…
212	for reading.	557	for reading.
213		558
214	The write queue is very simple: you can add data to its end, and	559	The write queue is very simple: you can add data to its end, and
215	AnyEvent::Handle will automatically try to get rid of it for you.	560	AnyEvent::Handle will automatically try to get rid of it for you.
216		561
217	When data could be writtena nd the write buffer is shorter then the low	562	When data could be written and the write buffer is shorter then the low
218	water mark, the C<on_drain> callback will be invoked.	563	water mark, the C<on_drain> callback will be invoked.
219		564
220	=over 4	565	=over 4
221		566
222	=item $handle->on_drain ($cb)	567	=item $handle->on_drain ($cb)
…		…
230	my ($self, $cb) = @_;	575	my ($self, $cb) = @_;
231		576
232	$self->{on_drain} = $cb;	577	$self->{on_drain} = $cb;
233		578
234	$cb->($self)	579	$cb->($self)
235	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	580	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
236	}	581	}
237		582
238	=item $handle->push_write ($data)	583	=item $handle->push_write ($data)
239		584
240	Queues the given scalar to be written. You can push as much data as you	585	Queues the given scalar to be written. You can push as much data as you
241	want (only limited by the available memory), as C<AnyEvent::Handle>	586	want (only limited by the available memory), as C<AnyEvent::Handle>
242	buffers it independently of the kernel.	587	buffers it independently of the kernel.
243		588
244	=cut	589	=cut
245		590
246	sub push_write {	591	sub _drain_wbuf {
247	my ($self, $data) = @_;	592	my ($self) = @_;
248		593
249	$self->{wbuf} .= $data;	594	if (!$self->{_ww} && length $self->{wbuf}) {
250		595
251	unless ($self->{ww}) {
252	Scalar::Util::weaken $self;	596	Scalar::Util::weaken $self;
		597
253	my $cb = sub {	598	my $cb = sub {
254	my $len = syswrite $self->{fh}, $self->{wbuf};	599	my $len = syswrite $self->{fh}, $self->{wbuf};
255		600
256	if ($len > 0) {	601	if (defined $len) {
257	substr $self->{wbuf}, 0, $len, "";	602	substr $self->{wbuf}, 0, $len, "";
258		603
		604	$self->{_activity} = AnyEvent->now;
259		605
260	$self->{on_drain}($self)	606	$self->{on_drain}($self)
261	if $self->{low_water_mark} >= length $self->{wbuf}	607	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
262	&& $self->{on_drain};	608	&& $self->{on_drain};
263		609
264	delete $self->{ww} unless length $self->{wbuf};	610	delete $self->{_ww} unless length $self->{wbuf};
265	} elsif ($! != EAGAIN && $! != EINTR) {	611	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
266	$self->error;	612	$self->_error ($!, 1);
267	}	613	}
268	};	614	};
269		615
		616	# try to write data immediately
		617	$cb->() unless $self->{autocork};
		618
		619	# if still data left in wbuf, we need to poll
270	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	620	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
271		621	if length $self->{wbuf};
272	$cb->($self);
273	};	622	};
274	}	623	}
		624
		625	our %WH;
		626
		627	sub register_write_type($$) {
		628	$WH{$_[0]} = $_[1];
		629	}
		630
		631	sub push_write {
		632	my $self = shift;
		633
		634	if (@_ > 1) {
		635	my $type = shift;
		636
		637	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		638	->($self, @_);
		639	}
		640
		641	if ($self->{tls}) {
		642	$self->{_tls_wbuf} .= $_[0];
		643
		644	&_dotls ($self);
		645	} else {
		646	$self->{wbuf} .= $_[0];
		647	$self->_drain_wbuf;
		648	}
		649	}
		650
		651	=item $handle->push_write (type => @args)
		652
		653	Instead of formatting your data yourself, you can also let this module do
		654	the job by specifying a type and type-specific arguments.
		655
		656	Predefined types are (if you have ideas for additional types, feel free to
		657	drop by and tell us):
		658
		659	=over 4
		660
		661	=item netstring => $string
		662
		663	Formats the given value as netstring
		664	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		665
		666	=cut
		667
		668	register_write_type netstring => sub {
		669	my ($self, $string) = @_;
		670
		671	(length $string) . ":$string,"
		672	};
		673
		674	=item packstring => $format, $data
		675
		676	An octet string prefixed with an encoded length. The encoding C<$format>
		677	uses the same format as a Perl C<pack> format, but must specify a single
		678	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		679	optional C<!>, C<< < >> or C<< > >> modifier).
		680
		681	=cut
		682
		683	register_write_type packstring => sub {
		684	my ($self, $format, $string) = @_;
		685
		686	pack "$format/a*", $string
		687	};
		688
		689	=item json => $array_or_hashref
		690
		691	Encodes the given hash or array reference into a JSON object. Unless you
		692	provide your own JSON object, this means it will be encoded to JSON text
		693	in UTF-8.
		694
		695	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		696	one end of a handle and read them at the other end without using any
		697	additional framing.
		698
		699	The generated JSON text is guaranteed not to contain any newlines: While
		700	this module doesn't need delimiters after or between JSON texts to be
		701	able to read them, many other languages depend on that.
		702
		703	A simple RPC protocol that interoperates easily with others is to send
		704	JSON arrays (or objects, although arrays are usually the better choice as
		705	they mimic how function argument passing works) and a newline after each
		706	JSON text:
		707
		708	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		709	$handle->push_write ("\012");
		710
		711	An AnyEvent::Handle receiver would simply use the C<json> read type and
		712	rely on the fact that the newline will be skipped as leading whitespace:
		713
		714	$handle->push_read (json => sub { my $array = $_[1]; ... });
		715
		716	Other languages could read single lines terminated by a newline and pass
		717	this line into their JSON decoder of choice.
		718
		719	=cut
		720
		721	register_write_type json => sub {
		722	my ($self, $ref) = @_;
		723
		724	require JSON;
		725
		726	$self->{json} ? $self->{json}->encode ($ref)
		727	: JSON::encode_json ($ref)
		728	};
		729
		730	=item storable => $reference
		731
		732	Freezes the given reference using L<Storable> and writes it to the
		733	handle. Uses the C<nfreeze> format.
		734
		735	=cut
		736
		737	register_write_type storable => sub {
		738	my ($self, $ref) = @_;
		739
		740	require Storable;
		741
		742	pack "w/a*", Storable::nfreeze ($ref)
		743	};
		744
		745	=back
		746
		747	=item $handle->push_shutdown
		748
		749	Sometimes you know you want to close the socket after writing your data
		750	before it was actually written. One way to do that is to replace your
		751	C<on_drain> handler by a callback that shuts down the socket (and set
		752	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		753	replaces the C<on_drain> callback with:
		754
		755	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		756
		757	This simply shuts down the write side and signals an EOF condition to the
		758	the peer.
		759
		760	You can rely on the normal read queue and C<on_eof> handling
		761	afterwards. This is the cleanest way to close a connection.
		762
		763	=cut
		764
		765	sub push_shutdown {
		766	my ($self) = @_;
		767
		768	delete $self->{low_water_mark};
		769	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		770	}
		771
		772	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		773
		774	This function (not method) lets you add your own types to C<push_write>.
		775	Whenever the given C<type> is used, C<push_write> will invoke the code
		776	reference with the handle object and the remaining arguments.
		777
		778	The code reference is supposed to return a single octet string that will
		779	be appended to the write buffer.
		780
		781	Note that this is a function, and all types registered this way will be
		782	global, so try to use unique names.
		783
		784	=cut
275		785
276	#############################################################################	786	#############################################################################
277		787
278	=back	788	=back
279		789
…		…
286	ways, the "simple" way, using only C<on_read> and the "complex" way, using	796	ways, the "simple" way, using only C<on_read> and the "complex" way, using
287	a queue.	797	a queue.
288		798
289	In the simple case, you just install an C<on_read> callback and whenever	799	In the simple case, you just install an C<on_read> callback and whenever
290	new data arrives, it will be called. You can then remove some data (if	800	new data arrives, it will be called. You can then remove some data (if
291	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	801	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
292	or not.	802	leave the data there if you want to accumulate more (e.g. when only a
		803	partial message has been received so far).
293		804
294	In the more complex case, you want to queue multiple callbacks. In this	805	In the more complex case, you want to queue multiple callbacks. In this
295	case, AnyEvent::Handle will call the first queued callback each time new	806	case, AnyEvent::Handle will call the first queued callback each time new
296	data arrives and removes it when it has done its job (see C<push_read>,	807	data arrives (also the first time it is queued) and removes it when it has
297	below).	808	done its job (see C<push_read>, below).
298		809
299	This way you can, for example, push three line-reads, followed by reading	810	This way you can, for example, push three line-reads, followed by reading
300	a chunk of data, and AnyEvent::Handle will execute them in order.	811	a chunk of data, and AnyEvent::Handle will execute them in order.
301		812
302	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	813	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
303	the specified number of bytes which give an XML datagram.	814	the specified number of bytes which give an XML datagram.
304		815
305	# in the default state, expect some header bytes	816	# in the default state, expect some header bytes
306	$handle->on_read (sub {	817	$handle->on_read (sub {
307	# some data is here, now queue the length-header-read (4 octets)	818	# some data is here, now queue the length-header-read (4 octets)
308	shift->unshift_read_chunk (4, sub {	819	shift->unshift_read (chunk => 4, sub {
309	# header arrived, decode	820	# header arrived, decode
310	my $len = unpack "N", $_[1];	821	my $len = unpack "N", $_[1];
311		822
312	# now read the payload	823	# now read the payload
313	shift->unshift_read_chunk ($len, sub {	824	shift->unshift_read (chunk => $len, sub {
314	my $xml = $_[1];	825	my $xml = $_[1];
315	# handle xml	826	# handle xml
316	});	827	});
317	});	828	});
318	});	829	});
319		830
320	Example 2: Implement a client for a protocol that replies either with	831	Example 2: Implement a client for a protocol that replies either with "OK"
321	"OK" and another line or "ERROR" for one request, and 64 bytes for the	832	and another line or "ERROR" for the first request that is sent, and 64
322	second request. Due tot he availability of a full queue, we can just	833	bytes for the second request. Due to the availability of a queue, we can
323	pipeline sending both requests and manipulate the queue as necessary in	834	just pipeline sending both requests and manipulate the queue as necessary
324	the callbacks:	835	in the callbacks.
325		836
326	# request one	837	When the first callback is called and sees an "OK" response, it will
		838	C<unshift> another line-read. This line-read will be queued I<before> the
		839	64-byte chunk callback.
		840
		841	# request one, returns either "OK + extra line" or "ERROR"
327	$handle->push_write ("request 1\015\012");	842	$handle->push_write ("request 1\015\012");
328		843
329	# we expect "ERROR" or "OK" as response, so push a line read	844	# we expect "ERROR" or "OK" as response, so push a line read
330	$handle->push_read_line (sub {	845	$handle->push_read (line => sub {
331	# if we got an "OK", we have to _prepend_ another line,	846	# if we got an "OK", we have to _prepend_ another line,
332	# so it will be read before the second request reads its 64 bytes	847	# so it will be read before the second request reads its 64 bytes
333	# which are already in the queue when this callback is called	848	# which are already in the queue when this callback is called
334	# we don't do this in case we got an error	849	# we don't do this in case we got an error
335	if ($_[1] eq "OK") {	850	if ($_[1] eq "OK") {
336	$_[0]->unshift_read_line (sub {	851	$_[0]->unshift_read (line => sub {
337	my $response = $_[1];	852	my $response = $_[1];
338	...	853	...
339	});	854	});
340	}	855	}
341	});	856	});
342		857
343	# request two	858	# request two, simply returns 64 octets
344	$handle->push_write ("request 2\015\012");	859	$handle->push_write ("request 2\015\012");
345		860
346	# simply read 64 bytes, always	861	# simply read 64 bytes, always
347	$handle->push_read_chunk (64, sub {	862	$handle->push_read (chunk => 64, sub {
348	my $response = $_[1];	863	my $response = $_[1];
349	...	864	...
350	});	865	});
351		866
352	=over 4	867	=over 4
353		868
		869	=cut
		870
354	sub _drain_rbuf {	871	sub _drain_rbuf {
355	my ($self) = @_;	872	my ($self) = @_;
356		873
357	return if exists $self->{in_drain};
358	local $self->{in_drain} = 1;	874	local $self->{_in_drain} = 1;
359		875
		876	if (
		877	defined $self->{rbuf_max}
		878	&& $self->{rbuf_max} < length $self->{rbuf}
		879	) {
		880	$self->_error (Errno::ENOSPC, 1), return;
		881	}
		882
		883	while () {
		884	# we need to use a separate tls read buffer, as we must not receive data while
		885	# we are draining the buffer, and this can only happen with TLS.
		886	$self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
		887
360	while (my $len = length $self->{rbuf}) {	888	my $len = length $self->{rbuf};
361	no strict 'refs';	889
362	if (@{ $self->{queue} }) {	890	if (my $cb = shift @{ $self->{_queue} }) {
363	if ($self->{queue}[0]($self)) {	891	unless ($cb->($self)) {
364	shift @{ $self->{queue} };
365	} elsif ($self->{eof}) {	892	if ($self->{_eof}) {
366	# no progress can be made (not enough data and no data forthcoming)	893	# no progress can be made (not enough data and no data forthcoming)
367	$! = &Errno::EPIPE; return $self->error;	894	$self->_error (Errno::EPIPE, 1), return;
368	} else {	895	}
		896
		897	unshift @{ $self->{_queue} }, $cb;
369	return;	898	last;
370	}	899	}
371	} elsif ($self->{on_read}) {	900	} elsif ($self->{on_read}) {
		901	last unless $len;
		902
372	$self->{on_read}($self);	903	$self->{on_read}($self);
373		904
374	if (	905	if (
375	$self->{eof} # if no further data will arrive
376	&& $len == length $self->{rbuf} # and no data has been consumed	906	$len == length $self->{rbuf} # if no data has been consumed
377	&& !@{ $self->{queue} } # and the queue is still empty	907	&& !@{ $self->{_queue} } # and the queue is still empty
378	&& $self->{on_read} # and we still want to read data	908	&& $self->{on_read} # but we still have on_read
379	) {	909	) {
		910	# no further data will arrive
380	# then no progress can be made	911	# so no progress can be made
381	$! = &Errno::EPIPE; return $self->error;	912	$self->_error (Errno::EPIPE, 1), return
		913	if $self->{_eof};
		914
		915	last; # more data might arrive
382	}	916	}
383	} else {	917	} else {
384	# read side becomes idle	918	# read side becomes idle
385	delete $self->{rw};	919	delete $self->{_rw} unless $self->{tls};
386	return;	920	last;
387	}	921	}
388	}	922	}
389		923
390	if ($self->{eof}) {	924	if ($self->{_eof}) {
391	$self->_shutdown;	925	if ($self->{on_eof}) {
392	$self->{on_eof}($self);	926	$self->{on_eof}($self)
		927	} else {
		928	$self->_error (0, 1, "Unexpected end-of-file");
		929	}
		930	}
		931
		932	# may need to restart read watcher
		933	unless ($self->{_rw}) {
		934	$self->start_read
		935	if $self->{on_read} || @{ $self->{_queue} };
393	}	936	}
394	}	937	}
395		938
396	=item $handle->on_read ($cb)	939	=item $handle->on_read ($cb)
397		940
…		…
403		946
404	sub on_read {	947	sub on_read {
405	my ($self, $cb) = @_;	948	my ($self, $cb) = @_;
406		949
407	$self->{on_read} = $cb;	950	$self->{on_read} = $cb;
408		951	$self->_drain_rbuf if $cb && !$self->{_in_drain};
409	unless ($self->{rw} || $self->{eof}) {
410	Scalar::Util::weaken $self;
411
412	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
413	my $len = sysread $self->{fh}, $self->{rbuf}, $self->{read_size} || 8192, length $self->{rbuf};
414
415	if ($len > 0) {
416	if (exists $self->{rbuf_max}) {
417	if ($self->{rbuf_max} < length $self->{rbuf}) {
418	$! = &Errno::ENOSPC; return $self->error;
419	}
420	}
421
422	} elsif (defined $len) {
423	$self->{eof} = 1;
424	delete $self->{rw};
425
426	} elsif ($! != EAGAIN && $! != EINTR) {
427	return $self->error;
428	}
429
430	$self->_drain_rbuf;
431	});
432	}
433	}	952	}
434		953
435	=item $handle->rbuf	954	=item $handle->rbuf
436		955
437	Returns the read buffer (as a modifiable lvalue).	956	Returns the read buffer (as a modifiable lvalue).
438		957
439	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	958	You can access the read buffer directly as the C<< ->{rbuf} >>
440	you want.	959	member, if you want. However, the only operation allowed on the
		960	read buffer (apart from looking at it) is removing data from its
		961	beginning. Otherwise modifying or appending to it is not allowed and will
		962	lead to hard-to-track-down bugs.
441		963
442	NOTE: The read buffer should only be used or modified if the C<on_read>,	964	NOTE: The read buffer should only be used or modified if the C<on_read>,
443	C<push_read> or C<unshift_read> methods are used. The other read methods	965	C<push_read> or C<unshift_read> methods are used. The other read methods
444	automatically manage the read buffer.	966	automatically manage the read buffer.
445		967
…		…
456	Append the given callback to the end of the queue (C<push_read>) or	978	Append the given callback to the end of the queue (C<push_read>) or
457	prepend it (C<unshift_read>).	979	prepend it (C<unshift_read>).
458		980
459	The callback is called each time some additional read data arrives.	981	The callback is called each time some additional read data arrives.
460		982
461	It must check wether enough data is in the read buffer already.	983	It must check whether enough data is in the read buffer already.
462		984
463	If not enough data is available, it must return the empty list or a false	985	If not enough data is available, it must return the empty list or a false
464	value, in which case it will be called repeatedly until enough data is	986	value, in which case it will be called repeatedly until enough data is
465	available (or an error condition is detected).	987	available (or an error condition is detected).
466		988
…		…
468	interested in (which can be none at all) and return a true value. After returning	990	interested in (which can be none at all) and return a true value. After returning
469	true, it will be removed from the queue.	991	true, it will be removed from the queue.
470		992
471	=cut	993	=cut
472		994
		995	our %RH;
		996
		997	sub register_read_type($$) {
		998	$RH{$_[0]} = $_[1];
		999	}
		1000
473	sub push_read {	1001	sub push_read {
474	my ($self, $cb) = @_;	1002	my $self = shift;
		1003	my $cb = pop;
475		1004
		1005	if (@_) {
		1006	my $type = shift;
		1007
		1008	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		1009	->($self, $cb, @_);
		1010	}
		1011
476	push @{ $self->{queue} }, $cb;	1012	push @{ $self->{_queue} }, $cb;
477	$self->_drain_rbuf;	1013	$self->_drain_rbuf unless $self->{_in_drain};
478	}	1014	}
479		1015
480	sub unshift_read {	1016	sub unshift_read {
481	my ($self, $cb) = @_;	1017	my $self = shift;
		1018	my $cb = pop;
482		1019
		1020	if (@_) {
		1021	my $type = shift;
		1022
		1023	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		1024	->($self, $cb, @_);
		1025	}
		1026
		1027
483	push @{ $self->{queue} }, $cb;	1028	unshift @{ $self->{_queue} }, $cb;
484	$self->_drain_rbuf;	1029	$self->_drain_rbuf unless $self->{_in_drain};
485	}	1030	}
486		1031
487	=item $handle->push_read_chunk ($len, $cb->($self, $data))	1032	=item $handle->push_read (type => @args, $cb)
488		1033
489	=item $handle->unshift_read_chunk ($len, $cb->($self, $data))	1034	=item $handle->unshift_read (type => @args, $cb)
490		1035
491	Append the given callback to the end of the queue (C<push_read_chunk>) or	1036	Instead of providing a callback that parses the data itself you can chose
492	prepend it (C<unshift_read_chunk>).	1037	between a number of predefined parsing formats, for chunks of data, lines
		1038	etc.
493		1039
494	The callback will be called only once C<$len> bytes have been read, and	1040	Predefined types are (if you have ideas for additional types, feel free to
495	these C<$len> bytes will be passed to the callback.	1041	drop by and tell us):
496		1042
497	=cut	1043	=over 4
498		1044
499	sub _read_chunk($$) {	1045	=item chunk => $octets, $cb->($handle, $data)
500	my ($len, $cb) = @_;	1046
		1047	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1048	data read to the callback. The callback will never be called with less
		1049	data.
		1050
		1051	Example: read 2 bytes.
		1052
		1053	$handle->push_read (chunk => 2, sub {
		1054	warn "yay ", unpack "H*", $_[1];
		1055	});
		1056
		1057	=cut
		1058
		1059	register_read_type chunk => sub {
		1060	my ($self, $cb, $len) = @_;
501		1061
502	sub {	1062	sub {
503	$len <= length $_[0]{rbuf} or return;	1063	$len <= length $_[0]{rbuf} or return;
504	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1064	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
505	1	1065	1
506	}	1066	}
507	}	1067	};
508		1068
509	sub push_read_chunk {	1069	=item line => [$eol, ]$cb->($handle, $line, $eol)
510	my ($self, $len, $cb) = @_;
511
512	$self->push_read (_read_chunk $len, $cb);
513	}
514
515
516	sub unshift_read_chunk {
517	my ($self, $len, $cb) = @_;
518
519	$self->unshift_read (_read_chunk $len, $cb);
520	}
521
522	=item $handle->push_read_line ([$eol, ]$cb->($self, $line, $eol))
523
524	=item $handle->unshift_read_line ([$eol, ]$cb->($self, $line, $eol))
525
526	Append the given callback to the end of the queue (C<push_read_line>) or
527	prepend it (C<unshift_read_line>).
528		1070
529	The callback will be called only once a full line (including the end of	1071	The callback will be called only once a full line (including the end of
530	line marker, C<$eol>) has been read. This line (excluding the end of line	1072	line marker, C<$eol>) has been read. This line (excluding the end of line
531	marker) will be passed to the callback as second argument (C<$line>), and	1073	marker) will be passed to the callback as second argument (C<$line>), and
532	the end of line marker as the third argument (C<$eol>).	1074	the end of line marker as the third argument (C<$eol>).
…		…
543	Partial lines at the end of the stream will never be returned, as they are	1085	Partial lines at the end of the stream will never be returned, as they are
544	not marked by the end of line marker.	1086	not marked by the end of line marker.
545		1087
546	=cut	1088	=cut
547		1089
548	sub _read_line($$) {	1090	register_read_type line => sub {
549	my $cb = pop;	1091	my ($self, $cb, $eol) = @_;
550	my $eol = @_ ? shift : qr|(\015?\012)|;
551	my $pos;
552		1092
		1093	if (@_ < 3) {
		1094	# this is more than twice as fast as the generic code below
		1095	sub {
		1096	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1097
		1098	$cb->($_[0], $1, $2);
		1099	1
		1100	}
		1101	} else {
553	$eol = qr|(\Q$eol\E)| unless ref $eol;	1102	$eol = quotemeta $eol unless ref $eol;
554	$eol = qr|^(.*?)($eol)|;	1103	$eol = qr|^(.*?)($eol)|s;
		1104
		1105	sub {
		1106	$_[0]{rbuf} =~ s/$eol// or return;
		1107
		1108	$cb->($_[0], $1, $2);
		1109	1
		1110	}
		1111	}
		1112	};
		1113
		1114	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1115
		1116	Makes a regex match against the regex object C<$accept> and returns
		1117	everything up to and including the match.
		1118
		1119	Example: read a single line terminated by '\n'.
		1120
		1121	$handle->push_read (regex => qr<\n>, sub { ... });
		1122
		1123	If C<$reject> is given and not undef, then it determines when the data is
		1124	to be rejected: it is matched against the data when the C<$accept> regex
		1125	does not match and generates an C<EBADMSG> error when it matches. This is
		1126	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1127	receive buffer overflow).
		1128
		1129	Example: expect a single decimal number followed by whitespace, reject
		1130	anything else (not the use of an anchor).
		1131
		1132	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1133
		1134	If C<$skip> is given and not C<undef>, then it will be matched against
		1135	the receive buffer when neither C<$accept> nor C<$reject> match,
		1136	and everything preceding and including the match will be accepted
		1137	unconditionally. This is useful to skip large amounts of data that you
		1138	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1139	have to start matching from the beginning. This is purely an optimisation
		1140	and is usually worth only when you expect more than a few kilobytes.
		1141
		1142	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1143	expect the header to be very large (it isn't in practise, but...), we use
		1144	a skip regex to skip initial portions. The skip regex is tricky in that
		1145	it only accepts something not ending in either \015 or \012, as these are
		1146	required for the accept regex.
		1147
		1148	$handle->push_read (regex =>
		1149	qr<\015\012\015\012>,
		1150	undef, # no reject
		1151	qr<^.*[^\015\012]>,
		1152	sub { ... });
		1153
		1154	=cut
		1155
		1156	register_read_type regex => sub {
		1157	my ($self, $cb, $accept, $reject, $skip) = @_;
		1158
		1159	my $data;
		1160	my $rbuf = \$self->{rbuf};
555		1161
556	sub {	1162	sub {
557	$_[0]{rbuf} =~ s/$eol// or return;	1163	# accept
		1164	if ($$rbuf =~ $accept) {
		1165	$data .= substr $$rbuf, 0, $+[0], "";
		1166	$cb->($self, $data);
		1167	return 1;
		1168	}
		1169
		1170	# reject
		1171	if ($reject && $$rbuf =~ $reject) {
		1172	$self->_error (Errno::EBADMSG);
		1173	}
558		1174
559	$cb->($1, $2);	1175	# skip
		1176	if ($skip && $$rbuf =~ $skip) {
		1177	$data .= substr $$rbuf, 0, $+[0], "";
		1178	}
		1179
		1180	()
		1181	}
		1182	};
		1183
		1184	=item netstring => $cb->($handle, $string)
		1185
		1186	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1187
		1188	Throws an error with C<$!> set to EBADMSG on format violations.
		1189
		1190	=cut
		1191
		1192	register_read_type netstring => sub {
		1193	my ($self, $cb) = @_;
		1194
		1195	sub {
		1196	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1197	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1198	$self->_error (Errno::EBADMSG);
		1199	}
		1200	return;
		1201	}
		1202
		1203	my $len = $1;
		1204
		1205	$self->unshift_read (chunk => $len, sub {
		1206	my $string = $_[1];
		1207	$_[0]->unshift_read (chunk => 1, sub {
		1208	if ($_[1] eq ",") {
		1209	$cb->($_[0], $string);
		1210	} else {
		1211	$self->_error (Errno::EBADMSG);
		1212	}
		1213	});
		1214	});
		1215
560	1	1216	1
561	}	1217	}
562	}	1218	};
563		1219
564	sub push_read_line {	1220	=item packstring => $format, $cb->($handle, $string)
565	my $self = shift;
566		1221
567	$self->push_read (&_read_line);	1222	An octet string prefixed with an encoded length. The encoding C<$format>
568	}	1223	uses the same format as a Perl C<pack> format, but must specify a single
		1224	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1225	optional C<!>, C<< < >> or C<< > >> modifier).
569		1226
570	sub unshift_read_line {	1227	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
571	my $self = shift;	1228	EPP uses a prefix of C<N> (4 octtes).
572		1229
573	$self->unshift_read (&_read_line);	1230	Example: read a block of data prefixed by its length in BER-encoded
574	}	1231	format (very efficient).
		1232
		1233	$handle->push_read (packstring => "w", sub {
		1234	my ($handle, $data) = @_;
		1235	});
		1236
		1237	=cut
		1238
		1239	register_read_type packstring => sub {
		1240	my ($self, $cb, $format) = @_;
		1241
		1242	sub {
		1243	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1244	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1245	or return;
		1246
		1247	$format = length pack $format, $len;
		1248
		1249	# bypass unshift if we already have the remaining chunk
		1250	if ($format + $len <= length $_[0]{rbuf}) {
		1251	my $data = substr $_[0]{rbuf}, $format, $len;
		1252	substr $_[0]{rbuf}, 0, $format + $len, "";
		1253	$cb->($_[0], $data);
		1254	} else {
		1255	# remove prefix
		1256	substr $_[0]{rbuf}, 0, $format, "";
		1257
		1258	# read remaining chunk
		1259	$_[0]->unshift_read (chunk => $len, $cb);
		1260	}
		1261
		1262	1
		1263	}
		1264	};
		1265
		1266	=item json => $cb->($handle, $hash_or_arrayref)
		1267
		1268	Reads a JSON object or array, decodes it and passes it to the
		1269	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1270
		1271	If a C<json> object was passed to the constructor, then that will be used
		1272	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1273
		1274	This read type uses the incremental parser available with JSON version
		1275	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1276	dependency on your own: this module will load the JSON module, but
		1277	AnyEvent does not depend on it itself.
		1278
		1279	Since JSON texts are fully self-delimiting, the C<json> read and write
		1280	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1281	the C<json> write type description, above, for an actual example.
		1282
		1283	=cut
		1284
		1285	register_read_type json => sub {
		1286	my ($self, $cb) = @_;
		1287
		1288	my $json = $self->{json} ||=
		1289	eval { require JSON::XS; JSON::XS->new->utf8 }
		1290	|| do { require JSON; JSON->new->utf8 };
		1291
		1292	my $data;
		1293	my $rbuf = \$self->{rbuf};
		1294
		1295	sub {
		1296	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1297
		1298	if ($ref) {
		1299	$self->{rbuf} = $json->incr_text;
		1300	$json->incr_text = "";
		1301	$cb->($self, $ref);
		1302
		1303	1
		1304	} elsif ($@) {
		1305	# error case
		1306	$json->incr_skip;
		1307
		1308	$self->{rbuf} = $json->incr_text;
		1309	$json->incr_text = "";
		1310
		1311	$self->_error (Errno::EBADMSG);
		1312
		1313	()
		1314	} else {
		1315	$self->{rbuf} = "";
		1316
		1317	()
		1318	}
		1319	}
		1320	};
		1321
		1322	=item storable => $cb->($handle, $ref)
		1323
		1324	Deserialises a L<Storable> frozen representation as written by the
		1325	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1326	data).
		1327
		1328	Raises C<EBADMSG> error if the data could not be decoded.
		1329
		1330	=cut
		1331
		1332	register_read_type storable => sub {
		1333	my ($self, $cb) = @_;
		1334
		1335	require Storable;
		1336
		1337	sub {
		1338	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1339	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1340	or return;
		1341
		1342	my $format = length pack "w", $len;
		1343
		1344	# bypass unshift if we already have the remaining chunk
		1345	if ($format + $len <= length $_[0]{rbuf}) {
		1346	my $data = substr $_[0]{rbuf}, $format, $len;
		1347	substr $_[0]{rbuf}, 0, $format + $len, "";
		1348	$cb->($_[0], Storable::thaw ($data));
		1349	} else {
		1350	# remove prefix
		1351	substr $_[0]{rbuf}, 0, $format, "";
		1352
		1353	# read remaining chunk
		1354	$_[0]->unshift_read (chunk => $len, sub {
		1355	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1356	$cb->($_[0], $ref);
		1357	} else {
		1358	$self->_error (Errno::EBADMSG);
		1359	}
		1360	});
		1361	}
		1362
		1363	1
		1364	}
		1365	};
575		1366
576	=back	1367	=back
577		1368
		1369	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1370
		1371	This function (not method) lets you add your own types to C<push_read>.
		1372
		1373	Whenever the given C<type> is used, C<push_read> will invoke the code
		1374	reference with the handle object, the callback and the remaining
		1375	arguments.
		1376
		1377	The code reference is supposed to return a callback (usually a closure)
		1378	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1379
		1380	It should invoke the passed callback when it is done reading (remember to
		1381	pass C<$handle> as first argument as all other callbacks do that).
		1382
		1383	Note that this is a function, and all types registered this way will be
		1384	global, so try to use unique names.
		1385
		1386	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1387	search for C<register_read_type>)).
		1388
		1389	=item $handle->stop_read
		1390
		1391	=item $handle->start_read
		1392
		1393	In rare cases you actually do not want to read anything from the
		1394	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1395	any queued callbacks will be executed then. To start reading again, call
		1396	C<start_read>.
		1397
		1398	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1399	you change the C<on_read> callback or push/unshift a read callback, and it
		1400	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1401	there are any read requests in the queue.
		1402
		1403	These methods will have no effect when in TLS mode (as TLS doesn't support
		1404	half-duplex connections).
		1405
		1406	=cut
		1407
		1408	sub stop_read {
		1409	my ($self) = @_;
		1410
		1411	delete $self->{_rw} unless $self->{tls};
		1412	}
		1413
		1414	sub start_read {
		1415	my ($self) = @_;
		1416
		1417	unless ($self->{_rw} || $self->{_eof}) {
		1418	Scalar::Util::weaken $self;
		1419
		1420	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1421	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1422	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1423
		1424	if ($len > 0) {
		1425	$self->{_activity} = AnyEvent->now;
		1426
		1427	if ($self->{tls}) {
		1428	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1429
		1430	&_dotls ($self);
		1431	} else {
		1432	$self->_drain_rbuf unless $self->{_in_drain};
		1433	}
		1434
		1435	} elsif (defined $len) {
		1436	delete $self->{_rw};
		1437	$self->{_eof} = 1;
		1438	$self->_drain_rbuf unless $self->{_in_drain};
		1439
		1440	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1441	return $self->_error ($!, 1);
		1442	}
		1443	});
		1444	}
		1445	}
		1446
		1447	our $ERROR_SYSCALL;
		1448	our $ERROR_WANT_READ;
		1449
		1450	sub _tls_error {
		1451	my ($self, $err) = @_;
		1452
		1453	return $self->_error ($!, 1)
		1454	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1455
		1456	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1457
		1458	# reduce error string to look less scary
		1459	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1460
		1461	if ($self->{_on_starttls}) {
		1462	(delete $self->{_on_starttls})->($self, undef, $err);
		1463	&_freetls;
		1464	} else {
		1465	&_freetls;
		1466	$self->_error (Errno::EPROTO, 1, $err);
		1467	}
		1468	}
		1469
		1470	# poll the write BIO and send the data if applicable
		1471	# also decode read data if possible
		1472	# this is basiclaly our TLS state machine
		1473	# more efficient implementations are possible with openssl,
		1474	# but not with the buggy and incomplete Net::SSLeay.
		1475	sub _dotls {
		1476	my ($self) = @_;
		1477
		1478	my $tmp;
		1479
		1480	if (length $self->{_tls_wbuf}) {
		1481	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
		1482	substr $self->{_tls_wbuf}, 0, $tmp, "";
		1483	}
		1484
		1485	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1486	return $self->_tls_error ($tmp)
		1487	if $tmp != $ERROR_WANT_READ
		1488	&& ($tmp != $ERROR_SYSCALL || $!);
		1489	}
		1490
		1491	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1492	unless (length $tmp) {
		1493	$self->{_on_starttls}
		1494	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1495	&_freetls;
		1496
		1497	if ($self->{on_stoptls}) {
		1498	$self->{on_stoptls}($self);
		1499	return;
		1500	} else {
		1501	# let's treat SSL-eof as we treat normal EOF
		1502	delete $self->{_rw};
		1503	$self->{_eof} = 1;
		1504	}
		1505	}
		1506
		1507	$self->{_tls_rbuf} .= $tmp;
		1508	$self->_drain_rbuf unless $self->{_in_drain};
		1509	$self->{tls} or return; # tls session might have gone away in callback
		1510	}
		1511
		1512	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1513	return $self->_tls_error ($tmp)
		1514	if $tmp != $ERROR_WANT_READ
		1515	&& ($tmp != $ERROR_SYSCALL || $!);
		1516
		1517	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1518	$self->{wbuf} .= $tmp;
		1519	$self->_drain_wbuf;
		1520	}
		1521
		1522	$self->{_on_starttls}
		1523	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
		1524	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
		1525	}
		1526
		1527	=item $handle->starttls ($tls[, $tls_ctx])
		1528
		1529	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1530	object is created, you can also do that at a later time by calling
		1531	C<starttls>.
		1532
		1533	Starting TLS is currently an asynchronous operation - when you push some
		1534	write data and then call C<< ->starttls >> then TLS negotiation will start
		1535	immediately, after which the queued write data is then sent.
		1536
		1537	The first argument is the same as the C<tls> constructor argument (either
		1538	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1539
		1540	The second argument is the optional C<AnyEvent::TLS> object that is used
		1541	when AnyEvent::Handle has to create its own TLS connection object, or
		1542	a hash reference with C<< key => value >> pairs that will be used to
		1543	construct a new context.
		1544
		1545	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1546	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1547	changed to your liking. Note that the handshake might have already started
		1548	when this function returns.
		1549
		1550	If it an error to start a TLS handshake more than once per
		1551	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1552
		1553	=cut
		1554
		1555	our %TLS_CACHE; #TODO not yet documented, should we?
		1556
		1557	sub starttls {
		1558	my ($self, $ssl, $ctx) = @_;
		1559
		1560	require Net::SSLeay;
		1561
		1562	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
		1563	if $self->{tls};
		1564
		1565	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1566	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1567
		1568	$ctx ||= $self->{tls_ctx};
		1569
		1570	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1571
		1572	if ("HASH" eq ref $ctx) {
		1573	require AnyEvent::TLS;
		1574
		1575	if ($ctx->{cache}) {
		1576	my $key = $ctx+0;
		1577	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1578	} else {
		1579	$ctx = new AnyEvent::TLS %$ctx;
		1580	}
		1581	}
		1582
		1583	$self->{tls_ctx} = $ctx || TLS_CTX ();
		1584	$self->{tls} = $ssl = $self->{tls_ctx}->_get_session ($ssl, $self, $self->{peername});
		1585
		1586	# basically, this is deep magic (because SSL_read should have the same issues)
		1587	# but the openssl maintainers basically said: "trust us, it just works".
		1588	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1589	# and mismaintained ssleay-module doesn't even offer them).
		1590	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1591	#
		1592	# in short: this is a mess.
		1593	#
		1594	# note that we do not try to keep the length constant between writes as we are required to do.
		1595	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1596	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1597	# have identity issues in that area.
		1598	# Net::SSLeay::CTX_set_mode ($ssl,
		1599	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1600	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1601	Net::SSLeay::CTX_set_mode ($ssl, 1|2);
		1602
		1603	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1604	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1605
		1606	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
		1607
		1608	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
		1609	if $self->{on_starttls};
		1610
		1611	&_dotls; # need to trigger the initial handshake
		1612	$self->start_read; # make sure we actually do read
		1613	}
		1614
		1615	=item $handle->stoptls
		1616
		1617	Shuts down the SSL connection - this makes a proper EOF handshake by
		1618	sending a close notify to the other side, but since OpenSSL doesn't
		1619	support non-blocking shut downs, it is not possible to re-use the stream
		1620	afterwards.
		1621
		1622	=cut
		1623
		1624	sub stoptls {
		1625	my ($self) = @_;
		1626
		1627	if ($self->{tls}) {
		1628	Net::SSLeay::shutdown ($self->{tls});
		1629
		1630	&_dotls;
		1631
		1632	# # we don't give a shit. no, we do, but we can't. no...#d#
		1633	# # we, we... have to use openssl :/#d#
		1634	# &_freetls;#d#
		1635	}
		1636	}
		1637
		1638	sub _freetls {
		1639	my ($self) = @_;
		1640
		1641	return unless $self->{tls};
		1642
		1643	$self->{tls_ctx}->_put_session (delete $self->{tls});
		1644
		1645	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		1646	}
		1647
		1648	sub DESTROY {
		1649	my ($self) = @_;
		1650
		1651	&_freetls;
		1652
		1653	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1654
		1655	if ($linger && length $self->{wbuf} && $self->{fh}) {
		1656	my $fh = delete $self->{fh};
		1657	my $wbuf = delete $self->{wbuf};
		1658
		1659	my @linger;
		1660
		1661	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
		1662	my $len = syswrite $fh, $wbuf, length $wbuf;
		1663
		1664	if ($len > 0) {
		1665	substr $wbuf, 0, $len, "";
		1666	} else {
		1667	@linger = (); # end
		1668	}
		1669	});
		1670	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1671	@linger = ();
		1672	});
		1673	}
		1674	}
		1675
		1676	=item $handle->destroy
		1677
		1678	Shuts down the handle object as much as possible - this call ensures that
		1679	no further callbacks will be invoked and as many resources as possible
		1680	will be freed. You must not call any methods on the object afterwards.
		1681
		1682	Normally, you can just "forget" any references to an AnyEvent::Handle
		1683	object and it will simply shut down. This works in fatal error and EOF
		1684	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1685	callback, so when you want to destroy the AnyEvent::Handle object from
		1686	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1687	that case.
		1688
		1689	Destroying the handle object in this way has the advantage that callbacks
		1690	will be removed as well, so if those are the only reference holders (as
		1691	is common), then one doesn't need to do anything special to break any
		1692	reference cycles.
		1693
		1694	The handle might still linger in the background and write out remaining
		1695	data, as specified by the C<linger> option, however.
		1696
		1697	=cut
		1698
		1699	sub destroy {
		1700	my ($self) = @_;
		1701
		1702	$self->DESTROY;
		1703	%$self = ();
		1704	}
		1705
		1706	=item AnyEvent::Handle::TLS_CTX
		1707
		1708	This function creates and returns the AnyEvent::TLS object used by default
		1709	for TLS mode.
		1710
		1711	The context is created by calling L<AnyEvent::TLS> without any arguments.
		1712
		1713	=cut
		1714
		1715	our $TLS_CTX;
		1716
		1717	sub TLS_CTX() {
		1718	$TLS_CTX ||= do {
		1719	require AnyEvent::TLS;
		1720
		1721	new AnyEvent::TLS
		1722	}
		1723	}
		1724
		1725	=back
		1726
		1727
		1728	=head1 NONFREQUENTLY ASKED QUESTIONS
		1729
		1730	=over 4
		1731
		1732	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1733	still get further invocations!
		1734
		1735	That's because AnyEvent::Handle keeps a reference to itself when handling
		1736	read or write callbacks.
		1737
		1738	It is only safe to "forget" the reference inside EOF or error callbacks,
		1739	from within all other callbacks, you need to explicitly call the C<<
		1740	->destroy >> method.
		1741
		1742	=item I get different callback invocations in TLS mode/Why can't I pause
		1743	reading?
		1744
		1745	Unlike, say, TCP, TLS connections do not consist of two independent
		1746	communication channels, one for each direction. Or put differently. The
		1747	read and write directions are not independent of each other: you cannot
		1748	write data unless you are also prepared to read, and vice versa.
		1749
		1750	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1751	callback invocations when you are not expecting any read data - the reason
		1752	is that AnyEvent::Handle always reads in TLS mode.
		1753
		1754	During the connection, you have to make sure that you always have a
		1755	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1756	connection (or when you no longer want to use it) you can call the
		1757	C<destroy> method.
		1758
		1759	=item How do I read data until the other side closes the connection?
		1760
		1761	If you just want to read your data into a perl scalar, the easiest way
		1762	to achieve this is by setting an C<on_read> callback that does nothing,
		1763	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1764	will be in C<$_[0]{rbuf}>:
		1765
		1766	$handle->on_read (sub { });
		1767	$handle->on_eof (undef);
		1768	$handle->on_error (sub {
		1769	my $data = delete $_[0]{rbuf};
		1770	});
		1771
		1772	The reason to use C<on_error> is that TCP connections, due to latencies
		1773	and packets loss, might get closed quite violently with an error, when in
		1774	fact, all data has been received.
		1775
		1776	It is usually better to use acknowledgements when transferring data,
		1777	to make sure the other side hasn't just died and you got the data
		1778	intact. This is also one reason why so many internet protocols have an
		1779	explicit QUIT command.
		1780
		1781	=item I don't want to destroy the handle too early - how do I wait until
		1782	all data has been written?
		1783
		1784	After writing your last bits of data, set the C<on_drain> callback
		1785	and destroy the handle in there - with the default setting of
		1786	C<low_water_mark> this will be called precisely when all data has been
		1787	written to the socket:
		1788
		1789	$handle->push_write (...);
		1790	$handle->on_drain (sub {
		1791	warn "all data submitted to the kernel\n";
		1792	undef $handle;
		1793	});
		1794
		1795	If you just want to queue some data and then signal EOF to the other side,
		1796	consider using C<< ->push_shutdown >> instead.
		1797
		1798	=item I want to contact a TLS/SSL server, I don't care about security.
		1799
		1800	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		1801	simply connect to it and then create the AnyEvent::Handle with the C<tls>
		1802	parameter:
		1803
		1804	tcp_connect $host, $port, sub {
		1805	my ($fh) = @_;
		1806
		1807	my $handle = new AnyEvent::Handle
		1808	fh => $fh,
		1809	tls => "connect",
		1810	on_error => sub { ... };
		1811
		1812	$handle->push_write (...);
		1813	};
		1814
		1815	=item I want to contact a TLS/SSL server, I do care about security.
		1816
		1817	Then you should additionally enable certificate verification, including
		1818	peername verification, if the protocol you use supports it (see
		1819	L<AnyEvent::TLS>, C<verify_peername>).
		1820
		1821	E.g. for HTTPS:
		1822
		1823	tcp_connect $host, $port, sub {
		1824	my ($fh) = @_;
		1825
		1826	my $handle = new AnyEvent::Handle
		1827	fh => $fh,
		1828	peername => $host,
		1829	tls => "connect",
		1830	tls_ctx => { verify => 1, verify_peername => "https" },
		1831	...
		1832
		1833	Note that you must specify the hostname you connected to (or whatever
		1834	"peername" the protocol needs) as the C<peername> argument, otherwise no
		1835	peername verification will be done.
		1836
		1837	The above will use the system-dependent default set of trusted CA
		1838	certificates. If you want to check against a specific CA, add the
		1839	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		1840
		1841	tls_ctx => {
		1842	verify => 1,
		1843	verify_peername => "https",
		1844	ca_file => "my-ca-cert.pem",
		1845	},
		1846
		1847	=item I want to create a TLS/SSL server, how do I do that?
		1848
		1849	Well, you first need to get a server certificate and key. You have
		1850	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		1851	self-signed certificate (cheap. check the search engine of your choice,
		1852	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		1853	nice program for that purpose).
		1854
		1855	Then create a file with your private key (in PEM format, see
		1856	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		1857	file should then look like this:
		1858
		1859	-----BEGIN RSA PRIVATE KEY-----
		1860	...header data
		1861	... lots of base64'y-stuff
		1862	-----END RSA PRIVATE KEY-----
		1863
		1864	-----BEGIN CERTIFICATE-----
		1865	... lots of base64'y-stuff
		1866	-----END CERTIFICATE-----
		1867
		1868	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		1869	specify this file as C<cert_file>:
		1870
		1871	tcp_server undef, $port, sub {
		1872	my ($fh) = @_;
		1873
		1874	my $handle = new AnyEvent::Handle
		1875	fh => $fh,
		1876	tls => "accept",
		1877	tls_ctx => { cert_file => "my-server-keycert.pem" },
		1878	...
		1879
		1880	When you have intermediate CA certificates that your clients might not
		1881	know about, just append them to the C<cert_file>.
		1882
		1883	=back
		1884
		1885
		1886	=head1 SUBCLASSING AnyEvent::Handle
		1887
		1888	In many cases, you might want to subclass AnyEvent::Handle.
		1889
		1890	To make this easier, a given version of AnyEvent::Handle uses these
		1891	conventions:
		1892
		1893	=over 4
		1894
		1895	=item * all constructor arguments become object members.
		1896
		1897	At least initially, when you pass a C<tls>-argument to the constructor it
		1898	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1899	mutated later on (for example C<tls> will hold the TLS connection object).
		1900
		1901	=item * other object member names are prefixed with an C<_>.
		1902
		1903	All object members not explicitly documented (internal use) are prefixed
		1904	with an underscore character, so the remaining non-C<_>-namespace is free
		1905	for use for subclasses.
		1906
		1907	=item * all members not documented here and not prefixed with an underscore
		1908	are free to use in subclasses.
		1909
		1910	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1911	member variables, but thats just life, at least it is documented.
		1912
		1913	=back
		1914
578	=head1 AUTHOR	1915	=head1 AUTHOR
579		1916
580	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	1917	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
581		1918
582	=cut	1919	=cut

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