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Revision 1.31 by root, Sun May 25 00:08:49 2008 UTC vs.
Revision 1.193 by root, Mon Mar 15 18:51:30 2010 UTC

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict;
5
6	use AnyEvent ();
7	use AnyEvent::Util ();
8	use Scalar::Util ();
9	use Carp ();
10	use Fcntl ();
11	use Errno qw/EAGAIN EINTR/;
12
13	=head1 NAME	1	=head1 NAME
14		2
15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent	3	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
16
17	=cut
18
19	our $VERSION = '0.04';
20		4
21	=head1 SYNOPSIS	5	=head1 SYNOPSIS
22		6
23	use AnyEvent;	7	use AnyEvent;
24	use AnyEvent::Handle;	8	use AnyEvent::Handle;
25		9
26	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
27		11
28	my $handle =	12	my $hdl; $hdl = new AnyEvent::Handle
29	AnyEvent::Handle->new (
30	fh => \*STDIN,	13	fh => \*STDIN,
31	on_eof => sub {	14	on_error => sub {
32	$cv->broadcast;	15	my ($hdl, $fatal, $msg) = @_;
33	},	16	warn "got error $msg\n";
		17	$hdl->destroy;
		18	$cv->send;
34	);	19	};
35		20
36	# send some request line	21	# send some request line
37	$handle->push_write ("getinfo\015\012");	22	$hdl->push_write ("getinfo\015\012");
38		23
39	# read the response line	24	# read the response line
40	$handle->push_read (line => sub {	25	$hdl->push_read (line => sub {
41	my ($handle, $line) = @_;	26	my ($hdl, $line) = @_;
42	warn "read line <$line>\n";	27	warn "got line <$line>\n";
43	$cv->send;	28	$cv->send;
44	});	29	});
45		30
46	$cv->recv;	31	$cv->recv;
47		32
48	=head1 DESCRIPTION	33	=head1 DESCRIPTION
49		34
50	This module is a helper module to make it easier to do event-based I/O on	35	This module is a helper module to make it easier to do event-based I/O on
51	filehandles. For utility functions for doing non-blocking connects and accepts	36	filehandles.
52	on sockets see L<AnyEvent::Util>.	37
		38	The L<AnyEvent::Intro> tutorial contains some well-documented
		39	AnyEvent::Handle examples.
53		40
54	In the following, when the documentation refers to of "bytes" then this	41	In the following, when the documentation refers to of "bytes" then this
55	means characters. As sysread and syswrite are used for all I/O, their	42	means characters. As sysread and syswrite are used for all I/O, their
56	treatment of characters applies to this module as well.	43	treatment of characters applies to this module as well.
57		44
		45	At the very minimum, you should specify C<fh> or C<connect>, and the
		46	C<on_error> callback.
		47
58	All callbacks will be invoked with the handle object as their first	48	All callbacks will be invoked with the handle object as their first
59	argument.	49	argument.
60		50
		51	=cut
		52
		53	package AnyEvent::Handle;
		54
		55	use Scalar::Util ();
		56	use List::Util ();
		57	use Carp ();
		58	use Errno qw(EAGAIN EINTR);
		59
		60	use AnyEvent (); BEGIN { AnyEvent::common_sense }
		61	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		62
		63	our $VERSION = $AnyEvent::VERSION;
		64
		65	sub _load_func($) {
		66	my $func = $_[0];
		67
		68	unless (defined &$func) {
		69	my $pkg = $func;
		70	do {
		71	$pkg =~ s/::[^:]+$//
		72	or return;
		73	eval "require $pkg";
		74	} until defined &$func;
		75	}
		76
		77	\&$func
		78	}
		79
61	=head1 METHODS	80	=head1 METHODS
62		81
63	=over 4	82	=over 4
64		83
65	=item B<new (%args)>	84	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
66		85
67	The constructor supports these arguments (all as key => value pairs).	86	The constructor supports these arguments (all as C<< key => value >> pairs).
68		87
69	=over 4	88	=over 4
70		89
71	=item fh => $filehandle [MANDATORY]	90	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
72		91
73	The filehandle this L<AnyEvent::Handle> object will operate on.	92	The filehandle this L<AnyEvent::Handle> object will operate on.
74
75	NOTE: The filehandle will be set to non-blocking (using	93	NOTE: The filehandle will be set to non-blocking mode (using
76	AnyEvent::Util::fh_nonblocking).	94	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		95	that mode.
77		96
78	=item on_eof => $cb->($self)	97	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
79		98
80	Set the callback to be called on EOF.	99	Try to connect to the specified host and service (port), using
		100	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		101	default C<peername>.
81		102
82	While not mandatory, it is highly recommended to set an eof callback,	103	You have to specify either this parameter, or C<fh>, above.
83	otherwise you might end up with a closed socket while you are still
84	waiting for data.
85		104
		105	It is possible to push requests on the read and write queues, and modify
		106	properties of the stream, even while AnyEvent::Handle is connecting.
		107
		108	When this parameter is specified, then the C<on_prepare>,
		109	C<on_connect_error> and C<on_connect> callbacks will be called under the
		110	appropriate circumstances:
		111
		112	=over 4
		113
86	=item on_error => $cb->($self)	114	=item on_prepare => $cb->($handle)
87		115
		116	This (rarely used) callback is called before a new connection is
		117	attempted, but after the file handle has been created. It could be used to
		118	prepare the file handle with parameters required for the actual connect
		119	(as opposed to settings that can be changed when the connection is already
		120	established).
		121
		122	The return value of this callback should be the connect timeout value in
		123	seconds (or C<0>, or C<undef>, or the empty list, to indicate the default
		124	timeout is to be used).
		125
		126	=item on_connect => $cb->($handle, $host, $port, $retry->())
		127
		128	This callback is called when a connection has been successfully established.
		129
		130	The actual numeric host and port (the socket peername) are passed as
		131	parameters, together with a retry callback.
		132
		133	When, for some reason, the handle is not acceptable, then calling
		134	C<$retry> will continue with the next connection target (in case of
		135	multi-homed hosts or SRV records there can be multiple connection
		136	endpoints). At the time it is called the read and write queues, eof
		137	status, tls status and similar properties of the handle will have been
		138	reset.
		139
		140	In most cases, ignoring the C<$retry> parameter is the way to go.
		141
		142	=item on_connect_error => $cb->($handle, $message)
		143
		144	This callback is called when the connection could not be
		145	established. C<$!> will contain the relevant error code, and C<$message> a
		146	message describing it (usually the same as C<"$!">).
		147
		148	If this callback isn't specified, then C<on_error> will be called with a
		149	fatal error instead.
		150
		151	=back
		152
		153	=item on_error => $cb->($handle, $fatal, $message)
		154
88	This is the fatal error callback, that is called when, well, a fatal error	155	This is the error callback, which is called when, well, some error
89	occurs, such as not being able to resolve the hostname, failure to connect	156	occured, such as not being able to resolve the hostname, failure to
90	or a read error.	157	connect or a read error.
91		158
92	The object will not be in a usable state when this callback has been	159	Some errors are fatal (which is indicated by C<$fatal> being true). On
93	called.	160	fatal errors the handle object will be destroyed (by a call to C<< ->
		161	destroy >>) after invoking the error callback (which means you are free to
		162	examine the handle object). Examples of fatal errors are an EOF condition
		163	with active (but unsatisifable) read watchers (C<EPIPE>) or I/O errors. In
		164	cases where the other side can close the connection at their will it is
		165	often easiest to not report C<EPIPE> errors in this callback.
		166
		167	AnyEvent::Handle tries to find an appropriate error code for you to check
		168	against, but in some cases (TLS errors), this does not work well. It is
		169	recommended to always output the C<$message> argument in human-readable
		170	error messages (it's usually the same as C<"$!">).
		171
		172	Non-fatal errors can be retried by simply returning, but it is recommended
		173	to simply ignore this parameter and instead abondon the handle object
		174	when this callback is invoked. Examples of non-fatal errors are timeouts
		175	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
94		176
95	On callback entrance, the value of C<$!> contains the operating system	177	On callback entrance, the value of C<$!> contains the operating system
96	error (or C<ENOSPC>, C<EPIPE> or C<EBADMSG>).	178	error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		179	C<EPROTO>).
97		180
98	While not mandatory, it is I<highly> recommended to set this callback, as	181	While not mandatory, it is I<highly> recommended to set this callback, as
99	you will not be notified of errors otherwise. The default simply calls	182	you will not be notified of errors otherwise. The default simply calls
100	die.	183	C<croak>.
101		184
102	=item on_read => $cb->($self)	185	=item on_read => $cb->($handle)
103		186
104	This sets the default read callback, which is called when data arrives	187	This sets the default read callback, which is called when data arrives
105	and no read request is in the queue.	188	and no read request is in the queue (unlike read queue callbacks, this
		189	callback will only be called when at least one octet of data is in the
		190	read buffer).
106		191
107	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	192	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
108	method or access the C<$self->{rbuf}> member directly.	193	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		194	must not enlarge or modify the read buffer, you can only remove data at
		195	the beginning from it.
109		196
110	When an EOF condition is detected then AnyEvent::Handle will first try to	197	When an EOF condition is detected then AnyEvent::Handle will first try to
111	feed all the remaining data to the queued callbacks and C<on_read> before	198	feed all the remaining data to the queued callbacks and C<on_read> before
112	calling the C<on_eof> callback. If no progress can be made, then a fatal	199	calling the C<on_eof> callback. If no progress can be made, then a fatal
113	error will be raised (with C<$!> set to C<EPIPE>).	200	error will be raised (with C<$!> set to C<EPIPE>).
114		201
		202	Note that, unlike requests in the read queue, an C<on_read> callback
		203	doesn't mean you I<require> some data: if there is an EOF and there
		204	are outstanding read requests then an error will be flagged. With an
		205	C<on_read> callback, the C<on_eof> callback will be invoked.
		206
		207	=item on_eof => $cb->($handle)
		208
		209	Set the callback to be called when an end-of-file condition is detected,
		210	i.e. in the case of a socket, when the other side has closed the
		211	connection cleanly, and there are no outstanding read requests in the
		212	queue (if there are read requests, then an EOF counts as an unexpected
		213	connection close and will be flagged as an error).
		214
		215	For sockets, this just means that the other side has stopped sending data,
		216	you can still try to write data, and, in fact, one can return from the EOF
		217	callback and continue writing data, as only the read part has been shut
		218	down.
		219
		220	If an EOF condition has been detected but no C<on_eof> callback has been
		221	set, then a fatal error will be raised with C<$!> set to <0>.
		222
115	=item on_drain => $cb->()	223	=item on_drain => $cb->($handle)
116		224
117	This sets the callback that is called when the write buffer becomes empty	225	This sets the callback that is called when the write buffer becomes empty
118	(or when the callback is set and the buffer is empty already).	226	(or when the callback is set and the buffer is empty already).
119		227
120	To append to the write buffer, use the C<< ->push_write >> method.	228	To append to the write buffer, use the C<< ->push_write >> method.
121		229
		230	This callback is useful when you don't want to put all of your write data
		231	into the queue at once, for example, when you want to write the contents
		232	of some file to the socket you might not want to read the whole file into
		233	memory and push it into the queue, but instead only read more data from
		234	the file when the write queue becomes empty.
		235
		236	=item timeout => $fractional_seconds
		237
		238	=item rtimeout => $fractional_seconds
		239
		240	=item wtimeout => $fractional_seconds
		241
		242	If non-zero, then these enables an "inactivity" timeout: whenever this
		243	many seconds pass without a successful read or write on the underlying
		244	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
		245	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		246	error will be raised).
		247
		248	There are three variants of the timeouts that work fully independent
		249	of each other, for both read and write, just read, and just write:
		250	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		251	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		252	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		253
		254	Note that timeout processing is also active when you currently do not have
		255	any outstanding read or write requests: If you plan to keep the connection
		256	idle then you should disable the timout temporarily or ignore the timeout
		257	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		258	restart the timeout.
		259
		260	Zero (the default) disables this timeout.
		261
		262	=item on_timeout => $cb->($handle)
		263
		264	Called whenever the inactivity timeout passes. If you return from this
		265	callback, then the timeout will be reset as if some activity had happened,
		266	so this condition is not fatal in any way.
		267
122	=item rbuf_max => <bytes>	268	=item rbuf_max => <bytes>
123		269
124	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	270	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
125	when the read buffer ever (strictly) exceeds this size. This is useful to	271	when the read buffer ever (strictly) exceeds this size. This is useful to
126	avoid denial-of-service attacks.	272	avoid some forms of denial-of-service attacks.
127		273
128	For example, a server accepting connections from untrusted sources should	274	For example, a server accepting connections from untrusted sources should
129	be configured to accept only so-and-so much data that it cannot act on	275	be configured to accept only so-and-so much data that it cannot act on
130	(for example, when expecting a line, an attacker could send an unlimited	276	(for example, when expecting a line, an attacker could send an unlimited
131	amount of data without a callback ever being called as long as the line	277	amount of data without a callback ever being called as long as the line
132	isn't finished).	278	isn't finished).
133		279
		280	=item autocork => <boolean>
		281
		282	When disabled (the default), then C<push_write> will try to immediately
		283	write the data to the handle, if possible. This avoids having to register
		284	a write watcher and wait for the next event loop iteration, but can
		285	be inefficient if you write multiple small chunks (on the wire, this
		286	disadvantage is usually avoided by your kernel's nagle algorithm, see
		287	C<no_delay>, but this option can save costly syscalls).
		288
		289	When enabled, then writes will always be queued till the next event loop
		290	iteration. This is efficient when you do many small writes per iteration,
		291	but less efficient when you do a single write only per iteration (or when
		292	the write buffer often is full). It also increases write latency.
		293
		294	=item no_delay => <boolean>
		295
		296	When doing small writes on sockets, your operating system kernel might
		297	wait a bit for more data before actually sending it out. This is called
		298	the Nagle algorithm, and usually it is beneficial.
		299
		300	In some situations you want as low a delay as possible, which can be
		301	accomplishd by setting this option to a true value.
		302
		303	The default is your opertaing system's default behaviour (most likely
		304	enabled), this option explicitly enables or disables it, if possible.
		305
		306	=item keepalive => <boolean>
		307
		308	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		309	normally, TCP connections have no time-out once established, so TCP
		310	connections, once established, can stay alive forever even when the other
		311	side has long gone. TCP keepalives are a cheap way to take down long-lived
		312	TCP connections whent he other side becomes unreachable. While the default
		313	is OS-dependent, TCP keepalives usually kick in after around two hours,
		314	and, if the other side doesn't reply, take down the TCP connection some 10
		315	to 15 minutes later.
		316
		317	It is harmless to specify this option for file handles that do not support
		318	keepalives, and enabling it on connections that are potentially long-lived
		319	is usually a good idea.
		320
		321	=item oobinline => <boolean>
		322
		323	BSD majorly fucked up the implementation of TCP urgent data. The result
		324	is that almost no OS implements TCP according to the specs, and every OS
		325	implements it slightly differently.
		326
		327	If you want to handle TCP urgent data, then setting this flag (the default
		328	is enabled) gives you the most portable way of getting urgent data, by
		329	putting it into the stream.
		330
		331	Since BSD emulation of OOB data on top of TCP's urgent data can have
		332	security implications, AnyEvent::Handle sets this flag automatically
		333	unless explicitly specified. Note that setting this flag after
		334	establishing a connection I<may> be a bit too late (data loss could
		335	already have occured on BSD systems), but at least it will protect you
		336	from most attacks.
		337
134	=item read_size => <bytes>	338	=item read_size => <bytes>
135		339
136	The default read block size (the amount of bytes this module will try to read	340	The default read block size (the amount of bytes this module will
137	on each [loop iteration). Default: C<4096>.	341	try to read during each loop iteration, which affects memory
		342	requirements). Default: C<8192>.
138		343
139	=item low_water_mark => <bytes>	344	=item low_water_mark => <bytes>
140		345
141	Sets the amount of bytes (default: C<0>) that make up an "empty" write	346	Sets the amount of bytes (default: C<0>) that make up an "empty" write
142	buffer: If the write reaches this size or gets even samller it is	347	buffer: If the write reaches this size or gets even samller it is
143	considered empty.	348	considered empty.
144		349
		350	Sometimes it can be beneficial (for performance reasons) to add data to
		351	the write buffer before it is fully drained, but this is a rare case, as
		352	the operating system kernel usually buffers data as well, so the default
		353	is good in almost all cases.
		354
		355	=item linger => <seconds>
		356
		357	If non-zero (default: C<3600>), then the destructor of the
		358	AnyEvent::Handle object will check whether there is still outstanding
		359	write data and will install a watcher that will write this data to the
		360	socket. No errors will be reported (this mostly matches how the operating
		361	system treats outstanding data at socket close time).
		362
		363	This will not work for partial TLS data that could not be encoded
		364	yet. This data will be lost. Calling the C<stoptls> method in time might
		365	help.
		366
		367	=item peername => $string
		368
		369	A string used to identify the remote site - usually the DNS hostname
		370	(I<not> IDN!) used to create the connection, rarely the IP address.
		371
		372	Apart from being useful in error messages, this string is also used in TLS
		373	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		374	verification will be skipped when C<peername> is not specified or
		375	C<undef>.
		376
145	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	377	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
146		378
147	When this parameter is given, it enables TLS (SSL) mode, that means it	379	When this parameter is given, it enables TLS (SSL) mode, that means
148	will start making tls handshake and will transparently encrypt/decrypt	380	AnyEvent will start a TLS handshake as soon as the connection has been
149	data.	381	established and will transparently encrypt/decrypt data afterwards.
		382
		383	All TLS protocol errors will be signalled as C<EPROTO>, with an
		384	appropriate error message.
150		385
151	TLS mode requires Net::SSLeay to be installed (it will be loaded	386	TLS mode requires Net::SSLeay to be installed (it will be loaded
152	automatically when you try to create a TLS handle).	387	automatically when you try to create a TLS handle): this module doesn't
		388	have a dependency on that module, so if your module requires it, you have
		389	to add the dependency yourself.
153		390
154	For the TLS server side, use C<accept>, and for the TLS client side of a	391	Unlike TCP, TLS has a server and client side: for the TLS server side, use
155	connection, use C<connect> mode.	392	C<accept>, and for the TLS client side of a connection, use C<connect>
		393	mode.
156		394
157	You can also provide your own TLS connection object, but you have	395	You can also provide your own TLS connection object, but you have
158	to make sure that you call either C<Net::SSLeay::set_connect_state>	396	to make sure that you call either C<Net::SSLeay::set_connect_state>
159	or C<Net::SSLeay::set_accept_state> on it before you pass it to	397	or C<Net::SSLeay::set_accept_state> on it before you pass it to
160	AnyEvent::Handle.	398	AnyEvent::Handle. Also, this module will take ownership of this connection
		399	object.
161		400
		401	At some future point, AnyEvent::Handle might switch to another TLS
		402	implementation, then the option to use your own session object will go
		403	away.
		404
		405	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		406	passing in the wrong integer will lead to certain crash. This most often
		407	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		408	segmentation fault.
		409
162	See the C<starttls> method if you need to start TLs negotiation later.	410	See the C<< ->starttls >> method for when need to start TLS negotiation later.
163		411
164	=item tls_ctx => $ssl_ctx	412	=item tls_ctx => $anyevent_tls
165		413
166	Use the given Net::SSLeay::CTX object to create the new TLS connection	414	Use the given C<AnyEvent::TLS> object to create the new TLS connection
167	(unless a connection object was specified directly). If this parameter is	415	(unless a connection object was specified directly). If this parameter is
168	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	416	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
169		417
		418	Instead of an object, you can also specify a hash reference with C<< key
		419	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		420	new TLS context object.
		421
		422	=item on_starttls => $cb->($handle, $success[, $error_message])
		423
		424	This callback will be invoked when the TLS/SSL handshake has finished. If
		425	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		426	(C<on_stoptls> will not be called in this case).
		427
		428	The session in C<< $handle->{tls} >> can still be examined in this
		429	callback, even when the handshake was not successful.
		430
		431	TLS handshake failures will not cause C<on_error> to be invoked when this
		432	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		433
		434	Without this callback, handshake failures lead to C<on_error> being
		435	called, as normal.
		436
		437	Note that you cannot call C<starttls> right again in this callback. If you
		438	need to do that, start an zero-second timer instead whose callback can
		439	then call C<< ->starttls >> again.
		440
		441	=item on_stoptls => $cb->($handle)
		442
		443	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		444	set, then it will be invoked after freeing the TLS session. If it is not,
		445	then a TLS shutdown condition will be treated like a normal EOF condition
		446	on the handle.
		447
		448	The session in C<< $handle->{tls} >> can still be examined in this
		449	callback.
		450
		451	This callback will only be called on TLS shutdowns, not when the
		452	underlying handle signals EOF.
		453
		454	=item json => JSON or JSON::XS object
		455
		456	This is the json coder object used by the C<json> read and write types.
		457
		458	If you don't supply it, then AnyEvent::Handle will create and use a
		459	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		460	texts.
		461
		462	Note that you are responsible to depend on the JSON module if you want to
		463	use this functionality, as AnyEvent does not have a dependency itself.
		464
170	=back	465	=back
171		466
172	=cut	467	=cut
173		468
174	sub new {	469	sub new {
175	my $class = shift;	470	my $class = shift;
176
177	my $self = bless { @_ }, $class;	471	my $self = bless { @_ }, $class;
178		472
179	$self->{fh} or Carp::croak "mandatory argument fh is missing";	473	if ($self->{fh}) {
		474	$self->_start;
		475	return unless $self->{fh}; # could be gone by now
		476
		477	} elsif ($self->{connect}) {
		478	require AnyEvent::Socket;
		479
		480	$self->{peername} = $self->{connect}[0]
		481	unless exists $self->{peername};
		482
		483	$self->{_skip_drain_rbuf} = 1;
		484
		485	{
		486	Scalar::Util::weaken (my $self = $self);
		487
		488	$self->{_connect} =
		489	AnyEvent::Socket::tcp_connect (
		490	$self->{connect}[0],
		491	$self->{connect}[1],
		492	sub {
		493	my ($fh, $host, $port, $retry) = @_;
		494
		495	if ($fh) {
		496	$self->{fh} = $fh;
		497
		498	delete $self->{_skip_drain_rbuf};
		499	$self->_start;
		500
		501	$self->{on_connect}
		502	and $self->{on_connect}($self, $host, $port, sub {
		503	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		504	$self->{_skip_drain_rbuf} = 1;
		505	&$retry;
		506	});
		507
		508	} else {
		509	if ($self->{on_connect_error}) {
		510	$self->{on_connect_error}($self, "$!");
		511	$self->destroy;
		512	} else {
		513	$self->_error ($!, 1);
		514	}
		515	}
		516	},
		517	sub {
		518	local $self->{fh} = $_[0];
		519
		520	$self->{on_prepare}
		521	? $self->{on_prepare}->($self)
		522	: ()
		523	}
		524	);
		525	}
		526
		527	} else {
		528	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		529	}
		530
		531	$self
		532	}
		533
		534	sub _start {
		535	my ($self) = @_;
180		536
181	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	537	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
182		538
183	if ($self->{tls}) {	539	$self->{_activity} =
184	require Net::SSLeay;	540	$self->{_ractivity} =
		541	$self->{_wactivity} = AE::now;
		542
		543	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		544	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		545	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		546
		547	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		548	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		549
		550	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		551
185	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	552	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
186	}	553	if $self->{tls};
187		554
188	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
189	$self->on_error (delete $self->{on_error}) if $self->{on_error};
190	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	555	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};
191	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
192		556
193	$self->start_read;	557	$self->start_read
		558	if $self->{on_read} || @{ $self->{_queue} };
194		559
195	$self	560	$self->_drain_wbuf;
196	}	561	}
197		562
198	sub _shutdown {
199	my ($self) = @_;
200
201	delete $self->{rw};
202	delete $self->{ww};
203	delete $self->{fh};
204	}
205
206	sub error {	563	sub _error {
207	my ($self) = @_;	564	my ($self, $errno, $fatal, $message) = @_;
208		565
209	{	566	$! = $errno;
210	local $!;	567	$message ||= "$!";
211	$self->_shutdown;
212	}
213		568
214	if ($self->{on_error}) {	569	if ($self->{on_error}) {
215	$self->{on_error}($self);	570	$self->{on_error}($self, $fatal, $message);
216	} else {	571	$self->destroy if $fatal;
		572	} elsif ($self->{fh} || $self->{connect}) {
		573	$self->destroy;
217	Carp::croak "AnyEvent::Handle uncaught fatal error: $!";	574	Carp::croak "AnyEvent::Handle uncaught error: $message";
218	}	575	}
219	}	576	}
220		577
221	=item $fh = $handle->fh	578	=item $fh = $handle->fh
222		579
223	This method returns the file handle of the L<AnyEvent::Handle> object.	580	This method returns the file handle used to create the L<AnyEvent::Handle> object.
224		581
225	=cut	582	=cut
226		583
227	sub fh { $_[0]->{fh} }	584	sub fh { $_[0]{fh} }
228		585
229	=item $handle->on_error ($cb)	586	=item $handle->on_error ($cb)
230		587
231	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	588	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
232		589
…		…
244		601
245	sub on_eof {	602	sub on_eof {
246	$_[0]{on_eof} = $_[1];	603	$_[0]{on_eof} = $_[1];
247	}	604	}
248		605
		606	=item $handle->on_timeout ($cb)
		607
		608	=item $handle->on_rtimeout ($cb)
		609
		610	=item $handle->on_wtimeout ($cb)
		611
		612	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		613	callback, or disables the callback (but not the timeout) if C<$cb> =
		614	C<undef>. See the C<timeout> constructor argument and method.
		615
		616	=cut
		617
		618	# see below
		619
		620	=item $handle->autocork ($boolean)
		621
		622	Enables or disables the current autocork behaviour (see C<autocork>
		623	constructor argument). Changes will only take effect on the next write.
		624
		625	=cut
		626
		627	sub autocork {
		628	$_[0]{autocork} = $_[1];
		629	}
		630
		631	=item $handle->no_delay ($boolean)
		632
		633	Enables or disables the C<no_delay> setting (see constructor argument of
		634	the same name for details).
		635
		636	=cut
		637
		638	sub no_delay {
		639	$_[0]{no_delay} = $_[1];
		640
		641	eval {
		642	local $SIG{__DIE__};
		643	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		644	if $_[0]{fh};
		645	};
		646	}
		647
		648	=item $handle->keepalive ($boolean)
		649
		650	Enables or disables the C<keepalive> setting (see constructor argument of
		651	the same name for details).
		652
		653	=cut
		654
		655	sub keepalive {
		656	$_[0]{keepalive} = $_[1];
		657
		658	eval {
		659	local $SIG{__DIE__};
		660	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		661	if $_[0]{fh};
		662	};
		663	}
		664
		665	=item $handle->oobinline ($boolean)
		666
		667	Enables or disables the C<oobinline> setting (see constructor argument of
		668	the same name for details).
		669
		670	=cut
		671
		672	sub oobinline {
		673	$_[0]{oobinline} = $_[1];
		674
		675	eval {
		676	local $SIG{__DIE__};
		677	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		678	if $_[0]{fh};
		679	};
		680	}
		681
		682	=item $handle->keepalive ($boolean)
		683
		684	Enables or disables the C<keepalive> setting (see constructor argument of
		685	the same name for details).
		686
		687	=cut
		688
		689	sub keepalive {
		690	$_[0]{keepalive} = $_[1];
		691
		692	eval {
		693	local $SIG{__DIE__};
		694	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		695	if $_[0]{fh};
		696	};
		697	}
		698
		699	=item $handle->on_starttls ($cb)
		700
		701	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		702
		703	=cut
		704
		705	sub on_starttls {
		706	$_[0]{on_starttls} = $_[1];
		707	}
		708
		709	=item $handle->on_stoptls ($cb)
		710
		711	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		712
		713	=cut
		714
		715	sub on_stoptls {
		716	$_[0]{on_stoptls} = $_[1];
		717	}
		718
		719	=item $handle->rbuf_max ($max_octets)
		720
		721	Configures the C<rbuf_max> setting (C<undef> disables it).
		722
		723	=cut
		724
		725	sub rbuf_max {
		726	$_[0]{rbuf_max} = $_[1];
		727	}
		728
		729	#############################################################################
		730
		731	=item $handle->timeout ($seconds)
		732
		733	=item $handle->rtimeout ($seconds)
		734
		735	=item $handle->wtimeout ($seconds)
		736
		737	Configures (or disables) the inactivity timeout.
		738
		739	=item $handle->timeout_reset
		740
		741	=item $handle->rtimeout_reset
		742
		743	=item $handle->wtimeout_reset
		744
		745	Reset the activity timeout, as if data was received or sent.
		746
		747	These methods are cheap to call.
		748
		749	=cut
		750
		751	for my $dir ("", "r", "w") {
		752	my $timeout = "${dir}timeout";
		753	my $tw = "_${dir}tw";
		754	my $on_timeout = "on_${dir}timeout";
		755	my $activity = "_${dir}activity";
		756	my $cb;
		757
		758	*$on_timeout = sub {
		759	$_[0]{$on_timeout} = $_[1];
		760	};
		761
		762	*$timeout = sub {
		763	my ($self, $new_value) = @_;
		764
		765	$self->{$timeout} = $new_value;
		766	delete $self->{$tw}; &$cb;
		767	};
		768
		769	*{"${dir}timeout_reset"} = sub {
		770	$_[0]{$activity} = AE::now;
		771	};
		772
		773	# main workhorse:
		774	# reset the timeout watcher, as neccessary
		775	# also check for time-outs
		776	$cb = sub {
		777	my ($self) = @_;
		778
		779	if ($self->{$timeout} && $self->{fh}) {
		780	my $NOW = AE::now;
		781
		782	# when would the timeout trigger?
		783	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		784
		785	# now or in the past already?
		786	if ($after <= 0) {
		787	$self->{$activity} = $NOW;
		788
		789	if ($self->{$on_timeout}) {
		790	$self->{$on_timeout}($self);
		791	} else {
		792	$self->_error (Errno::ETIMEDOUT);
		793	}
		794
		795	# callback could have changed timeout value, optimise
		796	return unless $self->{$timeout};
		797
		798	# calculate new after
		799	$after = $self->{$timeout};
		800	}
		801
		802	Scalar::Util::weaken $self;
		803	return unless $self; # ->error could have destroyed $self
		804
		805	$self->{$tw} ||= AE::timer $after, 0, sub {
		806	delete $self->{$tw};
		807	$cb->($self);
		808	};
		809	} else {
		810	delete $self->{$tw};
		811	}
		812	}
		813	}
		814
249	#############################################################################	815	#############################################################################
250		816
251	=back	817	=back
252		818
253	=head2 WRITE QUEUE	819	=head2 WRITE QUEUE
…		…
266	=item $handle->on_drain ($cb)	832	=item $handle->on_drain ($cb)
267		833
268	Sets the C<on_drain> callback or clears it (see the description of	834	Sets the C<on_drain> callback or clears it (see the description of
269	C<on_drain> in the constructor).	835	C<on_drain> in the constructor).
270		836
		837	This method may invoke callbacks (and therefore the handle might be
		838	destroyed after it returns).
		839
271	=cut	840	=cut
272		841
273	sub on_drain {	842	sub on_drain {
274	my ($self, $cb) = @_;	843	my ($self, $cb) = @_;
275		844
276	$self->{on_drain} = $cb;	845	$self->{on_drain} = $cb;
277		846
278	$cb->($self)	847	$cb->($self)
279	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	848	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
280	}	849	}
281		850
282	=item $handle->push_write ($data)	851	=item $handle->push_write ($data)
283		852
284	Queues the given scalar to be written. You can push as much data as you	853	Queues the given scalar to be written. You can push as much data as you
285	want (only limited by the available memory), as C<AnyEvent::Handle>	854	want (only limited by the available memory), as C<AnyEvent::Handle>
286	buffers it independently of the kernel.	855	buffers it independently of the kernel.
287		856
		857	This method may invoke callbacks (and therefore the handle might be
		858	destroyed after it returns).
		859
288	=cut	860	=cut
289		861
290	sub _drain_wbuf {	862	sub _drain_wbuf {
291	my ($self) = @_;	863	my ($self) = @_;
292		864
293	if (!$self->{ww} && length $self->{wbuf}) {	865	if (!$self->{_ww} && length $self->{wbuf}) {
		866
294	Scalar::Util::weaken $self;	867	Scalar::Util::weaken $self;
		868
295	my $cb = sub {	869	my $cb = sub {
296	my $len = syswrite $self->{fh}, $self->{wbuf};	870	my $len = syswrite $self->{fh}, $self->{wbuf};
297		871
298	if ($len >= 0) {	872	if (defined $len) {
299	substr $self->{wbuf}, 0, $len, "";	873	substr $self->{wbuf}, 0, $len, "";
300		874
		875	$self->{_activity} = $self->{_wactivity} = AE::now;
		876
301	$self->{on_drain}($self)	877	$self->{on_drain}($self)
302	if $self->{low_water_mark} >= length $self->{wbuf}	878	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
303	&& $self->{on_drain};	879	&& $self->{on_drain};
304		880
305	delete $self->{ww} unless length $self->{wbuf};	881	delete $self->{_ww} unless length $self->{wbuf};
306	} elsif ($! != EAGAIN && $! != EINTR) {	882	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
307	$self->error;	883	$self->_error ($!, 1);
308	}	884	}
309	};	885	};
310		886
311	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	887	# try to write data immediately
		888	$cb->() unless $self->{autocork};
312		889
313	$cb->($self);	890	# if still data left in wbuf, we need to poll
		891	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		892	if length $self->{wbuf};
314	};	893	};
315	}	894	}
316		895
317	our %WH;	896	our %WH;
318		897
		898	# deprecated
319	sub register_write_type($$) {	899	sub register_write_type($$) {
320	$WH{$_[0]} = $_[1];	900	$WH{$_[0]} = $_[1];
321	}	901	}
322		902
323	sub push_write {	903	sub push_write {
324	my $self = shift;	904	my $self = shift;
325		905
326	if (@_ > 1) {	906	if (@_ > 1) {
327	my $type = shift;	907	my $type = shift;
328		908
		909	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
329	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	910	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
330	->($self, @_);	911	->($self, @_);
331	}	912	}
332		913
		914	# we downgrade here to avoid hard-to-track-down bugs,
		915	# and diagnose the problem earlier and better.
		916
333	if ($self->{filter_w}) {	917	if ($self->{tls}) {
334	$self->{filter_w}->($self, \$_[0]);	918	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		919	&_dotls ($self) if $self->{fh};
335	} else {	920	} else {
336	$self->{wbuf} .= $_[0];	921	utf8::downgrade $self->{wbuf} .= $_[0];
337	$self->_drain_wbuf;	922	$self->_drain_wbuf if $self->{fh};
338	}	923	}
339	}	924	}
340		925
341	=item $handle->push_write (type => @args)	926	=item $handle->push_write (type => @args)
342		927
343	=item $handle->unshift_write (type => @args)
344
345	Instead of formatting your data yourself, you can also let this module do	928	Instead of formatting your data yourself, you can also let this module
346	the job by specifying a type and type-specific arguments.	929	do the job by specifying a type and type-specific arguments. You
		930	can also specify the (fully qualified) name of a package, in which
		931	case AnyEvent tries to load the package and then expects to find the
		932	C<anyevent_read_type> function inside (see "custom write types", below).
347		933
348	Predefined types are (if you have ideas for additional types, feel free to	934	Predefined types are (if you have ideas for additional types, feel free to
349	drop by and tell us):	935	drop by and tell us):
350		936
351	=over 4	937	=over 4
…		…
353	=item netstring => $string	939	=item netstring => $string
354		940
355	Formats the given value as netstring	941	Formats the given value as netstring
356	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).	942	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
357		943
358	=back
359
360	=cut	944	=cut
361		945
362	register_write_type netstring => sub {	946	register_write_type netstring => sub {
363	my ($self, $string) = @_;	947	my ($self, $string) = @_;
364		948
365	sprintf "%d:%s,", (length $string), $string	949	(length $string) . ":$string,"
366	};	950	};
367		951
368	=item AnyEvent::Handle::register_write_type type => $coderef->($self, @args)	952	=item packstring => $format, $data
369		953
370	This function (not method) lets you add your own types to C<push_write>.	954	An octet string prefixed with an encoded length. The encoding C<$format>
		955	uses the same format as a Perl C<pack> format, but must specify a single
		956	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		957	optional C<!>, C<< < >> or C<< > >> modifier).
		958
		959	=cut
		960
		961	register_write_type packstring => sub {
		962	my ($self, $format, $string) = @_;
		963
		964	pack "$format/a*", $string
		965	};
		966
		967	=item json => $array_or_hashref
		968
		969	Encodes the given hash or array reference into a JSON object. Unless you
		970	provide your own JSON object, this means it will be encoded to JSON text
		971	in UTF-8.
		972
		973	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		974	one end of a handle and read them at the other end without using any
		975	additional framing.
		976
		977	The generated JSON text is guaranteed not to contain any newlines: While
		978	this module doesn't need delimiters after or between JSON texts to be
		979	able to read them, many other languages depend on that.
		980
		981	A simple RPC protocol that interoperates easily with others is to send
		982	JSON arrays (or objects, although arrays are usually the better choice as
		983	they mimic how function argument passing works) and a newline after each
		984	JSON text:
		985
		986	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		987	$handle->push_write ("\012");
		988
		989	An AnyEvent::Handle receiver would simply use the C<json> read type and
		990	rely on the fact that the newline will be skipped as leading whitespace:
		991
		992	$handle->push_read (json => sub { my $array = $_[1]; ... });
		993
		994	Other languages could read single lines terminated by a newline and pass
		995	this line into their JSON decoder of choice.
		996
		997	=cut
		998
		999	sub json_coder() {
		1000	eval { require JSON::XS; JSON::XS->new->utf8 }
		1001	|| do { require JSON; JSON->new->utf8 }
		1002	}
		1003
		1004	register_write_type json => sub {
		1005	my ($self, $ref) = @_;
		1006
		1007	my $json = $self->{json} ||= json_coder;
		1008
		1009	$json->encode ($ref)
		1010	};
		1011
		1012	=item storable => $reference
		1013
		1014	Freezes the given reference using L<Storable> and writes it to the
		1015	handle. Uses the C<nfreeze> format.
		1016
		1017	=cut
		1018
		1019	register_write_type storable => sub {
		1020	my ($self, $ref) = @_;
		1021
		1022	require Storable;
		1023
		1024	pack "w/a*", Storable::nfreeze ($ref)
		1025	};
		1026
		1027	=back
		1028
		1029	=item $handle->push_shutdown
		1030
		1031	Sometimes you know you want to close the socket after writing your data
		1032	before it was actually written. One way to do that is to replace your
		1033	C<on_drain> handler by a callback that shuts down the socket (and set
		1034	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1035	replaces the C<on_drain> callback with:
		1036
		1037	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		1038
		1039	This simply shuts down the write side and signals an EOF condition to the
		1040	the peer.
		1041
		1042	You can rely on the normal read queue and C<on_eof> handling
		1043	afterwards. This is the cleanest way to close a connection.
		1044
		1045	This method may invoke callbacks (and therefore the handle might be
		1046	destroyed after it returns).
		1047
		1048	=cut
		1049
		1050	sub push_shutdown {
		1051	my ($self) = @_;
		1052
		1053	delete $self->{low_water_mark};
		1054	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1055	}
		1056
		1057	=item custom write types - Package::anyevent_write_type $handle, @args
		1058
		1059	Instead of one of the predefined types, you can also specify the name of
		1060	a package. AnyEvent will try to load the package and then expects to find
		1061	a function named C<anyevent_write_type> inside. If it isn't found, it
		1062	progressively tries to load the parent package until it either finds the
		1063	function (good) or runs out of packages (bad).
		1064
371	Whenever the given C<type> is used, C<push_write> will invoke the code	1065	Whenever the given C<type> is used, C<push_write> will the function with
372	reference with the handle object and the remaining arguments.	1066	the handle object and the remaining arguments.
373		1067
374	The code reference is supposed to return a single octet string that will	1068	The function is supposed to return a single octet string that will be
375	be appended to the write buffer.	1069	appended to the write buffer, so you cna mentally treat this function as a
		1070	"arguments to on-the-wire-format" converter.
376		1071
377	Note that this is a function, and all types registered this way will be	1072	Example: implement a custom write type C<join> that joins the remaining
378	global, so try to use unique names.	1073	arguments using the first one.
		1074
		1075	$handle->push_write (My::Type => " ", 1,2,3);
		1076
		1077	# uses the following package, which can be defined in the "My::Type" or in
		1078	# the "My" modules to be auto-loaded, or just about anywhere when the
		1079	# My::Type::anyevent_write_type is defined before invoking it.
		1080
		1081	package My::Type;
		1082
		1083	sub anyevent_write_type {
		1084	my ($handle, $delim, @args) = @_;
		1085
		1086	join $delim, @args
		1087	}
379		1088
380	=cut	1089	=cut
381		1090
382	#############################################################################	1091	#############################################################################
383		1092
…		…
392	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1101	ways, the "simple" way, using only C<on_read> and the "complex" way, using
393	a queue.	1102	a queue.
394		1103
395	In the simple case, you just install an C<on_read> callback and whenever	1104	In the simple case, you just install an C<on_read> callback and whenever
396	new data arrives, it will be called. You can then remove some data (if	1105	new data arrives, it will be called. You can then remove some data (if
397	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1106	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
398	or not.	1107	leave the data there if you want to accumulate more (e.g. when only a
		1108	partial message has been received so far).
399		1109
400	In the more complex case, you want to queue multiple callbacks. In this	1110	In the more complex case, you want to queue multiple callbacks. In this
401	case, AnyEvent::Handle will call the first queued callback each time new	1111	case, AnyEvent::Handle will call the first queued callback each time new
402	data arrives and removes it when it has done its job (see C<push_read>,	1112	data arrives (also the first time it is queued) and removes it when it has
403	below).	1113	done its job (see C<push_read>, below).
404		1114
405	This way you can, for example, push three line-reads, followed by reading	1115	This way you can, for example, push three line-reads, followed by reading
406	a chunk of data, and AnyEvent::Handle will execute them in order.	1116	a chunk of data, and AnyEvent::Handle will execute them in order.
407		1117
408	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1118	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
409	the specified number of bytes which give an XML datagram.	1119	the specified number of bytes which give an XML datagram.
410		1120
411	# in the default state, expect some header bytes	1121	# in the default state, expect some header bytes
412	$handle->on_read (sub {	1122	$handle->on_read (sub {
413	# some data is here, now queue the length-header-read (4 octets)	1123	# some data is here, now queue the length-header-read (4 octets)
414	shift->unshift_read_chunk (4, sub {	1124	shift->unshift_read (chunk => 4, sub {
415	# header arrived, decode	1125	# header arrived, decode
416	my $len = unpack "N", $_[1];	1126	my $len = unpack "N", $_[1];
417		1127
418	# now read the payload	1128	# now read the payload
419	shift->unshift_read_chunk ($len, sub {	1129	shift->unshift_read (chunk => $len, sub {
420	my $xml = $_[1];	1130	my $xml = $_[1];
421	# handle xml	1131	# handle xml
422	});	1132	});
423	});	1133	});
424	});	1134	});
425		1135
426	Example 2: Implement a client for a protocol that replies either with	1136	Example 2: Implement a client for a protocol that replies either with "OK"
427	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1137	and another line or "ERROR" for the first request that is sent, and 64
428	second request. Due tot he availability of a full queue, we can just	1138	bytes for the second request. Due to the availability of a queue, we can
429	pipeline sending both requests and manipulate the queue as necessary in	1139	just pipeline sending both requests and manipulate the queue as necessary
430	the callbacks:	1140	in the callbacks.
431		1141
432	# request one	1142	When the first callback is called and sees an "OK" response, it will
		1143	C<unshift> another line-read. This line-read will be queued I<before> the
		1144	64-byte chunk callback.
		1145
		1146	# request one, returns either "OK + extra line" or "ERROR"
433	$handle->push_write ("request 1\015\012");	1147	$handle->push_write ("request 1\015\012");
434		1148
435	# we expect "ERROR" or "OK" as response, so push a line read	1149	# we expect "ERROR" or "OK" as response, so push a line read
436	$handle->push_read_line (sub {	1150	$handle->push_read (line => sub {
437	# if we got an "OK", we have to _prepend_ another line,	1151	# if we got an "OK", we have to _prepend_ another line,
438	# so it will be read before the second request reads its 64 bytes	1152	# so it will be read before the second request reads its 64 bytes
439	# which are already in the queue when this callback is called	1153	# which are already in the queue when this callback is called
440	# we don't do this in case we got an error	1154	# we don't do this in case we got an error
441	if ($_[1] eq "OK") {	1155	if ($_[1] eq "OK") {
442	$_[0]->unshift_read_line (sub {	1156	$_[0]->unshift_read (line => sub {
443	my $response = $_[1];	1157	my $response = $_[1];
444	...	1158	...
445	});	1159	});
446	}	1160	}
447	});	1161	});
448		1162
449	# request two	1163	# request two, simply returns 64 octets
450	$handle->push_write ("request 2\015\012");	1164	$handle->push_write ("request 2\015\012");
451		1165
452	# simply read 64 bytes, always	1166	# simply read 64 bytes, always
453	$handle->push_read_chunk (64, sub {	1167	$handle->push_read (chunk => 64, sub {
454	my $response = $_[1];	1168	my $response = $_[1];
455	...	1169	...
456	});	1170	});
457		1171
458	=over 4	1172	=over 4
459		1173
460	=cut	1174	=cut
461		1175
462	sub _drain_rbuf {	1176	sub _drain_rbuf {
463	my ($self) = @_;	1177	my ($self) = @_;
		1178
		1179	# avoid recursion
		1180	return if $self->{_skip_drain_rbuf};
		1181	local $self->{_skip_drain_rbuf} = 1;
		1182
		1183	while () {
		1184	# we need to use a separate tls read buffer, as we must not receive data while
		1185	# we are draining the buffer, and this can only happen with TLS.
		1186	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1187	if exists $self->{_tls_rbuf};
		1188
		1189	my $len = length $self->{rbuf};
		1190
		1191	if (my $cb = shift @{ $self->{_queue} }) {
		1192	unless ($cb->($self)) {
		1193	# no progress can be made
		1194	# (not enough data and no data forthcoming)
		1195	$self->_error (Errno::EPIPE, 1), return
		1196	if $self->{_eof};
		1197
		1198	unshift @{ $self->{_queue} }, $cb;
		1199	last;
		1200	}
		1201	} elsif ($self->{on_read}) {
		1202	last unless $len;
		1203
		1204	$self->{on_read}($self);
		1205
		1206	if (
		1207	$len == length $self->{rbuf} # if no data has been consumed
		1208	&& !@{ $self->{_queue} } # and the queue is still empty
		1209	&& $self->{on_read} # but we still have on_read
		1210	) {
		1211	# no further data will arrive
		1212	# so no progress can be made
		1213	$self->_error (Errno::EPIPE, 1), return
		1214	if $self->{_eof};
		1215
		1216	last; # more data might arrive
		1217	}
		1218	} else {
		1219	# read side becomes idle
		1220	delete $self->{_rw} unless $self->{tls};
		1221	last;
		1222	}
		1223	}
		1224
		1225	if ($self->{_eof}) {
		1226	$self->{on_eof}
		1227	? $self->{on_eof}($self)
		1228	: $self->_error (0, 1, "Unexpected end-of-file");
		1229
		1230	return;
		1231	}
464		1232
465	if (	1233	if (
466	defined $self->{rbuf_max}	1234	defined $self->{rbuf_max}
467	&& $self->{rbuf_max} < length $self->{rbuf}	1235	&& $self->{rbuf_max} < length $self->{rbuf}
468	) {	1236	) {
469	$! = &Errno::ENOSPC; return $self->error;	1237	$self->_error (Errno::ENOSPC, 1), return;
470	}	1238	}
471		1239
472	return if $self->{in_drain};	1240	# may need to restart read watcher
473	local $self->{in_drain} = 1;	1241	unless ($self->{_rw}) {
474		1242	$self->start_read
475	while (my $len = length $self->{rbuf}) {	1243	if $self->{on_read} || @{ $self->{_queue} };
476	no strict 'refs';
477	if (my $cb = shift @{ $self->{queue} }) {
478	unless ($cb->($self)) {
479	if ($self->{eof}) {
480	# no progress can be made (not enough data and no data forthcoming)
481	$! = &Errno::EPIPE; return $self->error;
482	}
483
484	unshift @{ $self->{queue} }, $cb;
485	return;
486	}
487	} elsif ($self->{on_read}) {
488	$self->{on_read}($self);
489
490	if (
491	$self->{eof} # if no further data will arrive
492	&& $len == length $self->{rbuf} # and no data has been consumed
493	&& !@{ $self->{queue} } # and the queue is still empty
494	&& $self->{on_read} # and we still want to read data
495	) {
496	# then no progress can be made
497	$! = &Errno::EPIPE; return $self->error;
498	}
499	} else {
500	# read side becomes idle
501	delete $self->{rw};
502	return;
503	}
504	}
505
506	if ($self->{eof}) {
507	$self->_shutdown;
508	$self->{on_eof}($self)
509	if $self->{on_eof};
510	}	1244	}
511	}	1245	}
512		1246
513	=item $handle->on_read ($cb)	1247	=item $handle->on_read ($cb)
514		1248
515	This replaces the currently set C<on_read> callback, or clears it (when	1249	This replaces the currently set C<on_read> callback, or clears it (when
516	the new callback is C<undef>). See the description of C<on_read> in the	1250	the new callback is C<undef>). See the description of C<on_read> in the
517	constructor.	1251	constructor.
518		1252
		1253	This method may invoke callbacks (and therefore the handle might be
		1254	destroyed after it returns).
		1255
519	=cut	1256	=cut
520		1257
521	sub on_read {	1258	sub on_read {
522	my ($self, $cb) = @_;	1259	my ($self, $cb) = @_;
523		1260
524	$self->{on_read} = $cb;	1261	$self->{on_read} = $cb;
		1262	$self->_drain_rbuf if $cb;
525	}	1263	}
526		1264
527	=item $handle->rbuf	1265	=item $handle->rbuf
528		1266
529	Returns the read buffer (as a modifiable lvalue).	1267	Returns the read buffer (as a modifiable lvalue).
530		1268
531	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1269	You can access the read buffer directly as the C<< ->{rbuf} >>
532	you want.	1270	member, if you want. However, the only operation allowed on the
		1271	read buffer (apart from looking at it) is removing data from its
		1272	beginning. Otherwise modifying or appending to it is not allowed and will
		1273	lead to hard-to-track-down bugs.
533		1274
534	NOTE: The read buffer should only be used or modified if the C<on_read>,	1275	NOTE: The read buffer should only be used or modified if the C<on_read>,
535	C<push_read> or C<unshift_read> methods are used. The other read methods	1276	C<push_read> or C<unshift_read> methods are used. The other read methods
536	automatically manage the read buffer.	1277	automatically manage the read buffer.
537		1278
…		…
558		1299
559	If enough data was available, then the callback must remove all data it is	1300	If enough data was available, then the callback must remove all data it is
560	interested in (which can be none at all) and return a true value. After returning	1301	interested in (which can be none at all) and return a true value. After returning
561	true, it will be removed from the queue.	1302	true, it will be removed from the queue.
562		1303
		1304	These methods may invoke callbacks (and therefore the handle might be
		1305	destroyed after it returns).
		1306
563	=cut	1307	=cut
564		1308
565	our %RH;	1309	our %RH;
566		1310
567	sub register_read_type($$) {	1311	sub register_read_type($$) {
…		…
573	my $cb = pop;	1317	my $cb = pop;
574		1318
575	if (@_) {	1319	if (@_) {
576	my $type = shift;	1320	my $type = shift;
577		1321
		1322	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
578	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	1323	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
579	->($self, $cb, @_);	1324	->($self, $cb, @_);
580	}	1325	}
581		1326
582	push @{ $self->{queue} }, $cb;	1327	push @{ $self->{_queue} }, $cb;
583	$self->_drain_rbuf;	1328	$self->_drain_rbuf;
584	}	1329	}
585		1330
586	sub unshift_read {	1331	sub unshift_read {
587	my $self = shift;	1332	my $self = shift;
…		…
592		1337
593	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")	1338	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
594	->($self, $cb, @_);	1339	->($self, $cb, @_);
595	}	1340	}
596		1341
597
598	unshift @{ $self->{queue} }, $cb;	1342	unshift @{ $self->{_queue} }, $cb;
599	$self->_drain_rbuf;	1343	$self->_drain_rbuf;
600	}	1344	}
601		1345
602	=item $handle->push_read (type => @args, $cb)	1346	=item $handle->push_read (type => @args, $cb)
603		1347
604	=item $handle->unshift_read (type => @args, $cb)	1348	=item $handle->unshift_read (type => @args, $cb)
605		1349
606	Instead of providing a callback that parses the data itself you can chose	1350	Instead of providing a callback that parses the data itself you can chose
607	between a number of predefined parsing formats, for chunks of data, lines	1351	between a number of predefined parsing formats, for chunks of data, lines
608	etc.	1352	etc. You can also specify the (fully qualified) name of a package, in
		1353	which case AnyEvent tries to load the package and then expects to find the
		1354	C<anyevent_read_type> function inside (see "custom read types", below).
609		1355
610	Predefined types are (if you have ideas for additional types, feel free to	1356	Predefined types are (if you have ideas for additional types, feel free to
611	drop by and tell us):	1357	drop by and tell us):
612		1358
613	=over 4	1359	=over 4
614		1360
615	=item chunk => $octets, $cb->($self, $data)	1361	=item chunk => $octets, $cb->($handle, $data)
616		1362
617	Invoke the callback only once C<$octets> bytes have been read. Pass the	1363	Invoke the callback only once C<$octets> bytes have been read. Pass the
618	data read to the callback. The callback will never be called with less	1364	data read to the callback. The callback will never be called with less
619	data.	1365	data.
620		1366
…		…
634	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1380	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
635	1	1381	1
636	}	1382	}
637	};	1383	};
638		1384
639	# compatibility with older API
640	sub push_read_chunk {
641	$_[0]->push_read (chunk => $_[1], $_[2]);
642	}
643
644	sub unshift_read_chunk {
645	$_[0]->unshift_read (chunk => $_[1], $_[2]);
646	}
647
648	=item line => [$eol, ]$cb->($self, $line, $eol)	1385	=item line => [$eol, ]$cb->($handle, $line, $eol)
649		1386
650	The callback will be called only once a full line (including the end of	1387	The callback will be called only once a full line (including the end of
651	line marker, C<$eol>) has been read. This line (excluding the end of line	1388	line marker, C<$eol>) has been read. This line (excluding the end of line
652	marker) will be passed to the callback as second argument (C<$line>), and	1389	marker) will be passed to the callback as second argument (C<$line>), and
653	the end of line marker as the third argument (C<$eol>).	1390	the end of line marker as the third argument (C<$eol>).
…		…
667	=cut	1404	=cut
668		1405
669	register_read_type line => sub {	1406	register_read_type line => sub {
670	my ($self, $cb, $eol) = @_;	1407	my ($self, $cb, $eol) = @_;
671		1408
672	$eol = qr|(\015?\012)| if @_ < 3;	1409	if (@_ < 3) {
		1410	# this is more than twice as fast as the generic code below
		1411	sub {
		1412	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1413
		1414	$cb->($_[0], $1, $2);
		1415	1
		1416	}
		1417	} else {
673	$eol = quotemeta $eol unless ref $eol;	1418	$eol = quotemeta $eol unless ref $eol;
674	$eol = qr|^(.*?)($eol)|s;	1419	$eol = qr|^(.*?)($eol)|s;
		1420
		1421	sub {
		1422	$_[0]{rbuf} =~ s/$eol// or return;
		1423
		1424	$cb->($_[0], $1, $2);
		1425	1
		1426	}
		1427	}
		1428	};
		1429
		1430	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1431
		1432	Makes a regex match against the regex object C<$accept> and returns
		1433	everything up to and including the match.
		1434
		1435	Example: read a single line terminated by '\n'.
		1436
		1437	$handle->push_read (regex => qr<\n>, sub { ... });
		1438
		1439	If C<$reject> is given and not undef, then it determines when the data is
		1440	to be rejected: it is matched against the data when the C<$accept> regex
		1441	does not match and generates an C<EBADMSG> error when it matches. This is
		1442	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1443	receive buffer overflow).
		1444
		1445	Example: expect a single decimal number followed by whitespace, reject
		1446	anything else (not the use of an anchor).
		1447
		1448	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1449
		1450	If C<$skip> is given and not C<undef>, then it will be matched against
		1451	the receive buffer when neither C<$accept> nor C<$reject> match,
		1452	and everything preceding and including the match will be accepted
		1453	unconditionally. This is useful to skip large amounts of data that you
		1454	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1455	have to start matching from the beginning. This is purely an optimisation
		1456	and is usually worth only when you expect more than a few kilobytes.
		1457
		1458	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1459	expect the header to be very large (it isn't in practise, but...), we use
		1460	a skip regex to skip initial portions. The skip regex is tricky in that
		1461	it only accepts something not ending in either \015 or \012, as these are
		1462	required for the accept regex.
		1463
		1464	$handle->push_read (regex =>
		1465	qr<\015\012\015\012>,
		1466	undef, # no reject
		1467	qr<^.*[^\015\012]>,
		1468	sub { ... });
		1469
		1470	=cut
		1471
		1472	register_read_type regex => sub {
		1473	my ($self, $cb, $accept, $reject, $skip) = @_;
		1474
		1475	my $data;
		1476	my $rbuf = \$self->{rbuf};
675		1477
676	sub {	1478	sub {
677	$_[0]{rbuf} =~ s/$eol// or return;	1479	# accept
678		1480	if ($$rbuf =~ $accept) {
679	$cb->($_[0], $1, $2);	1481	$data .= substr $$rbuf, 0, $+[0], "";
		1482	$cb->($self, $data);
		1483	return 1;
		1484	}
680	1	1485
		1486	# reject
		1487	if ($reject && $$rbuf =~ $reject) {
		1488	$self->_error (Errno::EBADMSG);
		1489	}
		1490
		1491	# skip
		1492	if ($skip && $$rbuf =~ $skip) {
		1493	$data .= substr $$rbuf, 0, $+[0], "";
		1494	}
		1495
		1496	()
681	}	1497	}
682	};	1498	};
683		1499
684	# compatibility with older API
685	sub push_read_line {
686	my $self = shift;
687	$self->push_read (line => @_);
688	}
689
690	sub unshift_read_line {
691	my $self = shift;
692	$self->unshift_read (line => @_);
693	}
694
695	=item netstring => $cb->($string)	1500	=item netstring => $cb->($handle, $string)
696		1501
697	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).	1502	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
698		1503
699	Throws an error with C<$!> set to EBADMSG on format violations.	1504	Throws an error with C<$!> set to EBADMSG on format violations.
700		1505
…		…
704	my ($self, $cb) = @_;	1509	my ($self, $cb) = @_;
705		1510
706	sub {	1511	sub {
707	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {	1512	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
708	if ($_[0]{rbuf} =~ /[^0-9]/) {	1513	if ($_[0]{rbuf} =~ /[^0-9]/) {
709	$! = &Errno::EBADMSG;	1514	$self->_error (Errno::EBADMSG);
710	$self->error;
711	}	1515	}
712	return;	1516	return;
713	}	1517	}
714		1518
715	my $len = $1;	1519	my $len = $1;
…		…
718	my $string = $_[1];	1522	my $string = $_[1];
719	$_[0]->unshift_read (chunk => 1, sub {	1523	$_[0]->unshift_read (chunk => 1, sub {
720	if ($_[1] eq ",") {	1524	if ($_[1] eq ",") {
721	$cb->($_[0], $string);	1525	$cb->($_[0], $string);
722	} else {	1526	} else {
723	$! = &Errno::EBADMSG;
724	$self->error;	1527	$self->_error (Errno::EBADMSG);
725	}	1528	}
726	});	1529	});
727	});	1530	});
728		1531
729	1	1532	1
730	}	1533	}
731	};	1534	};
732		1535
		1536	=item packstring => $format, $cb->($handle, $string)
		1537
		1538	An octet string prefixed with an encoded length. The encoding C<$format>
		1539	uses the same format as a Perl C<pack> format, but must specify a single
		1540	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1541	optional C<!>, C<< < >> or C<< > >> modifier).
		1542
		1543	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1544	EPP uses a prefix of C<N> (4 octtes).
		1545
		1546	Example: read a block of data prefixed by its length in BER-encoded
		1547	format (very efficient).
		1548
		1549	$handle->push_read (packstring => "w", sub {
		1550	my ($handle, $data) = @_;
		1551	});
		1552
		1553	=cut
		1554
		1555	register_read_type packstring => sub {
		1556	my ($self, $cb, $format) = @_;
		1557
		1558	sub {
		1559	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1560	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1561	or return;
		1562
		1563	$format = length pack $format, $len;
		1564
		1565	# bypass unshift if we already have the remaining chunk
		1566	if ($format + $len <= length $_[0]{rbuf}) {
		1567	my $data = substr $_[0]{rbuf}, $format, $len;
		1568	substr $_[0]{rbuf}, 0, $format + $len, "";
		1569	$cb->($_[0], $data);
		1570	} else {
		1571	# remove prefix
		1572	substr $_[0]{rbuf}, 0, $format, "";
		1573
		1574	# read remaining chunk
		1575	$_[0]->unshift_read (chunk => $len, $cb);
		1576	}
		1577
		1578	1
		1579	}
		1580	};
		1581
		1582	=item json => $cb->($handle, $hash_or_arrayref)
		1583
		1584	Reads a JSON object or array, decodes it and passes it to the
		1585	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1586
		1587	If a C<json> object was passed to the constructor, then that will be used
		1588	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1589
		1590	This read type uses the incremental parser available with JSON version
		1591	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1592	dependency on your own: this module will load the JSON module, but
		1593	AnyEvent does not depend on it itself.
		1594
		1595	Since JSON texts are fully self-delimiting, the C<json> read and write
		1596	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1597	the C<json> write type description, above, for an actual example.
		1598
		1599	=cut
		1600
		1601	register_read_type json => sub {
		1602	my ($self, $cb) = @_;
		1603
		1604	my $json = $self->{json} ||= json_coder;
		1605
		1606	my $data;
		1607	my $rbuf = \$self->{rbuf};
		1608
		1609	sub {
		1610	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1611
		1612	if ($ref) {
		1613	$self->{rbuf} = $json->incr_text;
		1614	$json->incr_text = "";
		1615	$cb->($self, $ref);
		1616
		1617	1
		1618	} elsif ($@) {
		1619	# error case
		1620	$json->incr_skip;
		1621
		1622	$self->{rbuf} = $json->incr_text;
		1623	$json->incr_text = "";
		1624
		1625	$self->_error (Errno::EBADMSG);
		1626
		1627	()
		1628	} else {
		1629	$self->{rbuf} = "";
		1630
		1631	()
		1632	}
		1633	}
		1634	};
		1635
		1636	=item storable => $cb->($handle, $ref)
		1637
		1638	Deserialises a L<Storable> frozen representation as written by the
		1639	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1640	data).
		1641
		1642	Raises C<EBADMSG> error if the data could not be decoded.
		1643
		1644	=cut
		1645
		1646	register_read_type storable => sub {
		1647	my ($self, $cb) = @_;
		1648
		1649	require Storable;
		1650
		1651	sub {
		1652	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1653	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1654	or return;
		1655
		1656	my $format = length pack "w", $len;
		1657
		1658	# bypass unshift if we already have the remaining chunk
		1659	if ($format + $len <= length $_[0]{rbuf}) {
		1660	my $data = substr $_[0]{rbuf}, $format, $len;
		1661	substr $_[0]{rbuf}, 0, $format + $len, "";
		1662	$cb->($_[0], Storable::thaw ($data));
		1663	} else {
		1664	# remove prefix
		1665	substr $_[0]{rbuf}, 0, $format, "";
		1666
		1667	# read remaining chunk
		1668	$_[0]->unshift_read (chunk => $len, sub {
		1669	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1670	$cb->($_[0], $ref);
		1671	} else {
		1672	$self->_error (Errno::EBADMSG);
		1673	}
		1674	});
		1675	}
		1676
		1677	1
		1678	}
		1679	};
		1680
733	=back	1681	=back
734		1682
735	=item AnyEvent::Handle::register_read_type type => $coderef->($self, $cb, @args)	1683	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
736		1684
737	This function (not method) lets you add your own types to C<push_read>.	1685	Instead of one of the predefined types, you can also specify the name
		1686	of a package. AnyEvent will try to load the package and then expects to
		1687	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1688	progressively tries to load the parent package until it either finds the
		1689	function (good) or runs out of packages (bad).
738		1690
739	Whenever the given C<type> is used, C<push_read> will invoke the code	1691	Whenever this type is used, C<push_read> will invoke the function with the
740	reference with the handle object, the callback and the remaining	1692	handle object, the original callback and the remaining arguments.
741	arguments.
742		1693
743	The code reference is supposed to return a callback (usually a closure)	1694	The function is supposed to return a callback (usually a closure) that
744	that works as a plain read callback (see C<< ->push_read ($cb) >>).	1695	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1696	mentally treat the function as a "configurable read type to read callback"
		1697	converter.
745		1698
746	It should invoke the passed callback when it is done reading (remember to	1699	It should invoke the original callback when it is done reading (remember
747	pass C<$self> as first argument as all other callbacks do that).	1700	to pass C<$handle> as first argument as all other callbacks do that,
		1701	although there is no strict requirement on this).
748		1702
749	Note that this is a function, and all types registered this way will be
750	global, so try to use unique names.
751
752	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,	1703	For examples, see the source of this module (F<perldoc -m
753	search for C<register_read_type>)).	1704	AnyEvent::Handle>, search for C<register_read_type>)).
754		1705
755	=item $handle->stop_read	1706	=item $handle->stop_read
756		1707
757	=item $handle->start_read	1708	=item $handle->start_read
758		1709
759	In rare cases you actually do not want to read anything from the	1710	In rare cases you actually do not want to read anything from the
760	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1711	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
761	any queued callbacks will be executed then. To start reading again, call	1712	any queued callbacks will be executed then. To start reading again, call
762	C<start_read>.	1713	C<start_read>.
763		1714
		1715	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1716	you change the C<on_read> callback or push/unshift a read callback, and it
		1717	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1718	there are any read requests in the queue.
		1719
		1720	These methods will have no effect when in TLS mode (as TLS doesn't support
		1721	half-duplex connections).
		1722
764	=cut	1723	=cut
765		1724
766	sub stop_read {	1725	sub stop_read {
767	my ($self) = @_;	1726	my ($self) = @_;
768		1727
769	delete $self->{rw};	1728	delete $self->{_rw} unless $self->{tls};
770	}	1729	}
771		1730
772	sub start_read {	1731	sub start_read {
773	my ($self) = @_;	1732	my ($self) = @_;
774		1733
775	unless ($self->{rw} || $self->{eof}) {	1734	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
776	Scalar::Util::weaken $self;	1735	Scalar::Util::weaken $self;
777		1736
778	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1737	$self->{_rw} = AE::io $self->{fh}, 0, sub {
779	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1738	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
780	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1739	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
781		1740
782	if ($len > 0) {	1741	if ($len > 0) {
783	$self->{filter_r}	1742	$self->{_activity} = $self->{_ractivity} = AE::now;
784	? $self->{filter_r}->($self, $rbuf)	1743
		1744	if ($self->{tls}) {
		1745	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1746
		1747	&_dotls ($self);
		1748	} else {
785	: $self->_drain_rbuf;	1749	$self->_drain_rbuf;
		1750	}
786		1751
787	} elsif (defined $len) {	1752	} elsif (defined $len) {
788	delete $self->{rw};	1753	delete $self->{_rw};
789	$self->{eof} = 1;	1754	$self->{_eof} = 1;
790	$self->_drain_rbuf;	1755	$self->_drain_rbuf;
791		1756
792	} elsif ($! != EAGAIN && $! != EINTR) {	1757	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
793	return $self->error;	1758	return $self->_error ($!, 1);
794	}	1759	}
795	});	1760	};
796	}	1761	}
797	}	1762	}
798		1763
		1764	our $ERROR_SYSCALL;
		1765	our $ERROR_WANT_READ;
		1766
		1767	sub _tls_error {
		1768	my ($self, $err) = @_;
		1769
		1770	return $self->_error ($!, 1)
		1771	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1772
		1773	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1774
		1775	# reduce error string to look less scary
		1776	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1777
		1778	if ($self->{_on_starttls}) {
		1779	(delete $self->{_on_starttls})->($self, undef, $err);
		1780	&_freetls;
		1781	} else {
		1782	&_freetls;
		1783	$self->_error (Errno::EPROTO, 1, $err);
		1784	}
		1785	}
		1786
		1787	# poll the write BIO and send the data if applicable
		1788	# also decode read data if possible
		1789	# this is basiclaly our TLS state machine
		1790	# more efficient implementations are possible with openssl,
		1791	# but not with the buggy and incomplete Net::SSLeay.
799	sub _dotls {	1792	sub _dotls {
800	my ($self) = @_;	1793	my ($self) = @_;
801		1794
		1795	my $tmp;
		1796
802	if (length $self->{tls_wbuf}) {	1797	if (length $self->{_tls_wbuf}) {
803	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{tls_wbuf})) > 0) {	1798	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
804	substr $self->{tls_wbuf}, 0, $len, "";	1799	substr $self->{_tls_wbuf}, 0, $tmp, "";
805	}	1800	}
806	}
807		1801
		1802	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1803	return $self->_tls_error ($tmp)
		1804	if $tmp != $ERROR_WANT_READ
		1805	&& ($tmp != $ERROR_SYSCALL || $!);
		1806	}
		1807
808	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{tls_wbio}))) {	1808	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1809	unless (length $tmp) {
		1810	$self->{_on_starttls}
		1811	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1812	&_freetls;
		1813
		1814	if ($self->{on_stoptls}) {
		1815	$self->{on_stoptls}($self);
		1816	return;
		1817	} else {
		1818	# let's treat SSL-eof as we treat normal EOF
		1819	delete $self->{_rw};
		1820	$self->{_eof} = 1;
		1821	}
		1822	}
		1823
		1824	$self->{_tls_rbuf} .= $tmp;
		1825	$self->_drain_rbuf;
		1826	$self->{tls} or return; # tls session might have gone away in callback
		1827	}
		1828
		1829	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1830	return $self->_tls_error ($tmp)
		1831	if $tmp != $ERROR_WANT_READ
		1832	&& ($tmp != $ERROR_SYSCALL || $!);
		1833
		1834	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
809	$self->{wbuf} .= $buf;	1835	$self->{wbuf} .= $tmp;
810	$self->_drain_wbuf;	1836	$self->_drain_wbuf;
		1837	$self->{tls} or return; # tls session might have gone away in callback
811	}	1838	}
812		1839
813	while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {	1840	$self->{_on_starttls}
814	$self->{rbuf} .= $buf;	1841	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
815	$self->_drain_rbuf;	1842	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
816	}
817
818	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
819
820	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
821	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
822	$self->error;
823	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
824	$! = &Errno::EIO;
825	$self->error;
826	}
827
828	# all others are fine for our purposes
829	}
830	}	1843	}
831		1844
832	=item $handle->starttls ($tls[, $tls_ctx])	1845	=item $handle->starttls ($tls[, $tls_ctx])
833		1846
834	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1847	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
835	object is created, you can also do that at a later time by calling	1848	object is created, you can also do that at a later time by calling
836	C<starttls>.	1849	C<starttls>.
837		1850
		1851	Starting TLS is currently an asynchronous operation - when you push some
		1852	write data and then call C<< ->starttls >> then TLS negotiation will start
		1853	immediately, after which the queued write data is then sent.
		1854
838	The first argument is the same as the C<tls> constructor argument (either	1855	The first argument is the same as the C<tls> constructor argument (either
839	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1856	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
840		1857
841	The second argument is the optional C<Net::SSLeay::CTX> object that is	1858	The second argument is the optional C<AnyEvent::TLS> object that is used
842	used when AnyEvent::Handle has to create its own TLS connection object.	1859	when AnyEvent::Handle has to create its own TLS connection object, or
		1860	a hash reference with C<< key => value >> pairs that will be used to
		1861	construct a new context.
843		1862
844	=cut	1863	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1864	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1865	changed to your liking. Note that the handshake might have already started
		1866	when this function returns.
845		1867
846	# TODO: maybe document...	1868	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1869	handshakes on the same stream. Best do not attempt to use the stream after
		1870	stopping TLS.
		1871
		1872	This method may invoke callbacks (and therefore the handle might be
		1873	destroyed after it returns).
		1874
		1875	=cut
		1876
		1877	our %TLS_CACHE; #TODO not yet documented, should we?
		1878
847	sub starttls {	1879	sub starttls {
848	my ($self, $ssl, $ctx) = @_;	1880	my ($self, $tls, $ctx) = @_;
849		1881
850	$self->stoptls;	1882	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1883	if $self->{tls};
851		1884
852	if ($ssl eq "accept") {	1885	$self->{tls} = $tls;
853	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1886	$self->{tls_ctx} = $ctx if @_ > 2;
854	Net::SSLeay::set_accept_state ($ssl);	1887
855	} elsif ($ssl eq "connect") {	1888	return unless $self->{fh};
856	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1889
857	Net::SSLeay::set_connect_state ($ssl);	1890	require Net::SSLeay;
		1891
		1892	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1893	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1894
		1895	$tls = delete $self->{tls};
		1896	$ctx = $self->{tls_ctx};
		1897
		1898	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1899
		1900	if ("HASH" eq ref $ctx) {
		1901	require AnyEvent::TLS;
		1902
		1903	if ($ctx->{cache}) {
		1904	my $key = $ctx+0;
		1905	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1906	} else {
		1907	$ctx = new AnyEvent::TLS %$ctx;
		1908	}
		1909	}
858	}	1910
859		1911	$self->{tls_ctx} = $ctx || TLS_CTX ();
860	$self->{tls} = $ssl;	1912	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
861		1913
862	# basically, this is deep magic (because SSL_read should have the same issues)	1914	# basically, this is deep magic (because SSL_read should have the same issues)
863	# but the openssl maintainers basically said: "trust us, it just works".	1915	# but the openssl maintainers basically said: "trust us, it just works".
864	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1916	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
865	# and mismaintained ssleay-module doesn't even offer them).	1917	# and mismaintained ssleay-module doesn't even offer them).
866	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1918	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1919	#
		1920	# in short: this is a mess.
		1921	#
		1922	# note that we do not try to keep the length constant between writes as we are required to do.
		1923	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1924	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1925	# have identity issues in that area.
867	Net::SSLeay::CTX_set_mode ($self->{tls},	1926	# Net::SSLeay::CTX_set_mode ($ssl,
868	(eval { Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	1927	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
869	| (eval { Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	1928	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1929	Net::SSLeay::CTX_set_mode ($tls, 1|2);
870		1930
871	$self->{tls_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1931	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
872	$self->{tls_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1932	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
873		1933
		1934	Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf});
		1935
874	Net::SSLeay::set_bio ($ssl, $self->{tls_rbio}, $self->{tls_wbio});	1936	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
875		1937
876	$self->{filter_w} = sub {	1938	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
877	$_[0]{tls_wbuf} .= ${$_[1]};	1939	if $self->{on_starttls};
878	&_dotls;	1940
879	};	1941	&_dotls; # need to trigger the initial handshake
880	$self->{filter_r} = sub {	1942	$self->start_read; # make sure we actually do read
881	Net::SSLeay::BIO_write ($_[0]{tls_rbio}, ${$_[1]});
882	&_dotls;
883	};
884	}	1943	}
885		1944
886	=item $handle->stoptls	1945	=item $handle->stoptls
887		1946
888	Destroys the SSL connection, if any. Partial read or write data will be	1947	Shuts down the SSL connection - this makes a proper EOF handshake by
889	lost.	1948	sending a close notify to the other side, but since OpenSSL doesn't
		1949	support non-blocking shut downs, it is not guaranteed that you can re-use
		1950	the stream afterwards.
		1951
		1952	This method may invoke callbacks (and therefore the handle might be
		1953	destroyed after it returns).
890		1954
891	=cut	1955	=cut
892		1956
893	sub stoptls {	1957	sub stoptls {
894	my ($self) = @_;	1958	my ($self) = @_;
895		1959
896	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	1960	if ($self->{tls} && $self->{fh}) {
897	delete $self->{tls_rbio};	1961	Net::SSLeay::shutdown ($self->{tls});
898	delete $self->{tls_wbio};	1962
899	delete $self->{tls_wbuf};	1963	&_dotls;
900	delete $self->{filter_r};	1964
901	delete $self->{filter_w};	1965	# # we don't give a shit. no, we do, but we can't. no...#d#
		1966	# # we, we... have to use openssl :/#d#
		1967	# &_freetls;#d#
		1968	}
		1969	}
		1970
		1971	sub _freetls {
		1972	my ($self) = @_;
		1973
		1974	return unless $self->{tls};
		1975
		1976	$self->{tls_ctx}->_put_session (delete $self->{tls})
		1977	if $self->{tls} > 0;
		1978
		1979	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
902	}	1980	}
903		1981
904	sub DESTROY {	1982	sub DESTROY {
905	my $self = shift;	1983	my ($self) = @_;
906		1984
907	$self->stoptls;	1985	&_freetls;
		1986
		1987	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1988
		1989	if ($linger && length $self->{wbuf} && $self->{fh}) {
		1990	my $fh = delete $self->{fh};
		1991	my $wbuf = delete $self->{wbuf};
		1992
		1993	my @linger;
		1994
		1995	push @linger, AE::io $fh, 1, sub {
		1996	my $len = syswrite $fh, $wbuf, length $wbuf;
		1997
		1998	if ($len > 0) {
		1999	substr $wbuf, 0, $len, "";
		2000	} else {
		2001	@linger = (); # end
		2002	}
		2003	};
		2004	push @linger, AE::timer $linger, 0, sub {
		2005	@linger = ();
		2006	};
		2007	}
908	}	2008	}
		2009
		2010	=item $handle->destroy
		2011
		2012	Shuts down the handle object as much as possible - this call ensures that
		2013	no further callbacks will be invoked and as many resources as possible
		2014	will be freed. Any method you will call on the handle object after
		2015	destroying it in this way will be silently ignored (and it will return the
		2016	empty list).
		2017
		2018	Normally, you can just "forget" any references to an AnyEvent::Handle
		2019	object and it will simply shut down. This works in fatal error and EOF
		2020	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2021	callback, so when you want to destroy the AnyEvent::Handle object from
		2022	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2023	that case.
		2024
		2025	Destroying the handle object in this way has the advantage that callbacks
		2026	will be removed as well, so if those are the only reference holders (as
		2027	is common), then one doesn't need to do anything special to break any
		2028	reference cycles.
		2029
		2030	The handle might still linger in the background and write out remaining
		2031	data, as specified by the C<linger> option, however.
		2032
		2033	=cut
		2034
		2035	sub destroy {
		2036	my ($self) = @_;
		2037
		2038	$self->DESTROY;
		2039	%$self = ();
		2040	bless $self, "AnyEvent::Handle::destroyed";
		2041	}
		2042
		2043	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2044	#nop
		2045	}
		2046
		2047	=item $handle->destroyed
		2048
		2049	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2050	->destroy >>, true otherwise.
		2051
		2052	Can be useful to decide whether the handle is still valid after some
		2053	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2054	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2055	can destroy the handle, so work can be avoided by checking sometimes:
		2056
		2057	$hdl->starttls ("accept");
		2058	return if $hdl->destroyed;
		2059	$hdl->push_write (...
		2060
		2061	Note that the call to C<push_write> will silently be ignored if the handle
		2062	has been destroyed, so often you can just ignore the possibility of the
		2063	handle being destroyed.
		2064
		2065	=cut
		2066
		2067	sub destroyed { 0 }
		2068	sub AnyEvent::Handle::destroyed::destroyed { 1 }
909		2069
910	=item AnyEvent::Handle::TLS_CTX	2070	=item AnyEvent::Handle::TLS_CTX
911		2071
912	This function creates and returns the Net::SSLeay::CTX object used by	2072	This function creates and returns the AnyEvent::TLS object used by default
913	default for TLS mode.	2073	for TLS mode.
914		2074
915	The context is created like this:	2075	The context is created by calling L<AnyEvent::TLS> without any arguments.
916
917	Net::SSLeay::load_error_strings;
918	Net::SSLeay::SSLeay_add_ssl_algorithms;
919	Net::SSLeay::randomize;
920
921	my $CTX = Net::SSLeay::CTX_new;
922
923	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
924		2076
925	=cut	2077	=cut
926		2078
927	our $TLS_CTX;	2079	our $TLS_CTX;
928		2080
929	sub TLS_CTX() {	2081	sub TLS_CTX() {
930	$TLS_CTX || do {	2082	$TLS_CTX ||= do {
931	require Net::SSLeay;	2083	require AnyEvent::TLS;
932		2084
933	Net::SSLeay::load_error_strings ();	2085	new AnyEvent::TLS
934	Net::SSLeay::SSLeay_add_ssl_algorithms ();
935	Net::SSLeay::randomize ();
936
937	$TLS_CTX = Net::SSLeay::CTX_new ();
938
939	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
940
941	$TLS_CTX
942	}	2086	}
943	}	2087	}
944		2088
945	=back	2089	=back
946		2090
		2091
		2092	=head1 NONFREQUENTLY ASKED QUESTIONS
		2093
		2094	=over 4
		2095
		2096	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2097	still get further invocations!
		2098
		2099	That's because AnyEvent::Handle keeps a reference to itself when handling
		2100	read or write callbacks.
		2101
		2102	It is only safe to "forget" the reference inside EOF or error callbacks,
		2103	from within all other callbacks, you need to explicitly call the C<<
		2104	->destroy >> method.
		2105
		2106	=item I get different callback invocations in TLS mode/Why can't I pause
		2107	reading?
		2108
		2109	Unlike, say, TCP, TLS connections do not consist of two independent
		2110	communication channels, one for each direction. Or put differently. The
		2111	read and write directions are not independent of each other: you cannot
		2112	write data unless you are also prepared to read, and vice versa.
		2113
		2114	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		2115	callback invocations when you are not expecting any read data - the reason
		2116	is that AnyEvent::Handle always reads in TLS mode.
		2117
		2118	During the connection, you have to make sure that you always have a
		2119	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2120	connection (or when you no longer want to use it) you can call the
		2121	C<destroy> method.
		2122
		2123	=item How do I read data until the other side closes the connection?
		2124
		2125	If you just want to read your data into a perl scalar, the easiest way
		2126	to achieve this is by setting an C<on_read> callback that does nothing,
		2127	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2128	will be in C<$_[0]{rbuf}>:
		2129
		2130	$handle->on_read (sub { });
		2131	$handle->on_eof (undef);
		2132	$handle->on_error (sub {
		2133	my $data = delete $_[0]{rbuf};
		2134	});
		2135
		2136	The reason to use C<on_error> is that TCP connections, due to latencies
		2137	and packets loss, might get closed quite violently with an error, when in
		2138	fact, all data has been received.
		2139
		2140	It is usually better to use acknowledgements when transferring data,
		2141	to make sure the other side hasn't just died and you got the data
		2142	intact. This is also one reason why so many internet protocols have an
		2143	explicit QUIT command.
		2144
		2145	=item I don't want to destroy the handle too early - how do I wait until
		2146	all data has been written?
		2147
		2148	After writing your last bits of data, set the C<on_drain> callback
		2149	and destroy the handle in there - with the default setting of
		2150	C<low_water_mark> this will be called precisely when all data has been
		2151	written to the socket:
		2152
		2153	$handle->push_write (...);
		2154	$handle->on_drain (sub {
		2155	warn "all data submitted to the kernel\n";
		2156	undef $handle;
		2157	});
		2158
		2159	If you just want to queue some data and then signal EOF to the other side,
		2160	consider using C<< ->push_shutdown >> instead.
		2161
		2162	=item I want to contact a TLS/SSL server, I don't care about security.
		2163
		2164	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2165	simply connect to it and then create the AnyEvent::Handle with the C<tls>
		2166	parameter:
		2167
		2168	tcp_connect $host, $port, sub {
		2169	my ($fh) = @_;
		2170
		2171	my $handle = new AnyEvent::Handle
		2172	fh => $fh,
		2173	tls => "connect",
		2174	on_error => sub { ... };
		2175
		2176	$handle->push_write (...);
		2177	};
		2178
		2179	=item I want to contact a TLS/SSL server, I do care about security.
		2180
		2181	Then you should additionally enable certificate verification, including
		2182	peername verification, if the protocol you use supports it (see
		2183	L<AnyEvent::TLS>, C<verify_peername>).
		2184
		2185	E.g. for HTTPS:
		2186
		2187	tcp_connect $host, $port, sub {
		2188	my ($fh) = @_;
		2189
		2190	my $handle = new AnyEvent::Handle
		2191	fh => $fh,
		2192	peername => $host,
		2193	tls => "connect",
		2194	tls_ctx => { verify => 1, verify_peername => "https" },
		2195	...
		2196
		2197	Note that you must specify the hostname you connected to (or whatever
		2198	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2199	peername verification will be done.
		2200
		2201	The above will use the system-dependent default set of trusted CA
		2202	certificates. If you want to check against a specific CA, add the
		2203	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2204
		2205	tls_ctx => {
		2206	verify => 1,
		2207	verify_peername => "https",
		2208	ca_file => "my-ca-cert.pem",
		2209	},
		2210
		2211	=item I want to create a TLS/SSL server, how do I do that?
		2212
		2213	Well, you first need to get a server certificate and key. You have
		2214	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2215	self-signed certificate (cheap. check the search engine of your choice,
		2216	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2217	nice program for that purpose).
		2218
		2219	Then create a file with your private key (in PEM format, see
		2220	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2221	file should then look like this:
		2222
		2223	-----BEGIN RSA PRIVATE KEY-----
		2224	...header data
		2225	... lots of base64'y-stuff
		2226	-----END RSA PRIVATE KEY-----
		2227
		2228	-----BEGIN CERTIFICATE-----
		2229	... lots of base64'y-stuff
		2230	-----END CERTIFICATE-----
		2231
		2232	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2233	specify this file as C<cert_file>:
		2234
		2235	tcp_server undef, $port, sub {
		2236	my ($fh) = @_;
		2237
		2238	my $handle = new AnyEvent::Handle
		2239	fh => $fh,
		2240	tls => "accept",
		2241	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2242	...
		2243
		2244	When you have intermediate CA certificates that your clients might not
		2245	know about, just append them to the C<cert_file>.
		2246
		2247	=back
		2248
		2249
		2250	=head1 SUBCLASSING AnyEvent::Handle
		2251
		2252	In many cases, you might want to subclass AnyEvent::Handle.
		2253
		2254	To make this easier, a given version of AnyEvent::Handle uses these
		2255	conventions:
		2256
		2257	=over 4
		2258
		2259	=item * all constructor arguments become object members.
		2260
		2261	At least initially, when you pass a C<tls>-argument to the constructor it
		2262	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2263	mutated later on (for example C<tls> will hold the TLS connection object).
		2264
		2265	=item * other object member names are prefixed with an C<_>.
		2266
		2267	All object members not explicitly documented (internal use) are prefixed
		2268	with an underscore character, so the remaining non-C<_>-namespace is free
		2269	for use for subclasses.
		2270
		2271	=item * all members not documented here and not prefixed with an underscore
		2272	are free to use in subclasses.
		2273
		2274	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2275	member variables, but thats just life, at least it is documented.
		2276
		2277	=back
		2278
947	=head1 AUTHOR	2279	=head1 AUTHOR
948		2280
949	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	2281	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
950		2282
951	=cut	2283	=cut

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