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Revision 1.30 by root, Sat May 24 23:56:26 2008 UTC vs.
Revision 1.201 by root, Wed Oct 13 01:15:57 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 streaming handles via AnyEvent
16
17	This module is experimental.
18
19	=cut
20
21	our $VERSION = '0.04';
22		4
23	=head1 SYNOPSIS	5	=head1 SYNOPSIS
24		6
25	use AnyEvent;	7	use AnyEvent;
26	use AnyEvent::Handle;	8	use AnyEvent::Handle;
27		9
28	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
29		11
30	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	12	my $hdl; $hdl = new AnyEvent::Handle
31
32	#TODO
33
34	# or use the constructor to pass the callback:
35
36	my $ae_fh2 =
37	AnyEvent::Handle->new (
38	fh => \*STDIN,	13	fh => \*STDIN,
39	on_eof => sub {	14	on_error => sub {
40	$cv->broadcast;	15	my ($hdl, $fatal, $msg) = @_;
41	},	16	warn "got error $msg\n";
42	#TODO	17	$hdl->destroy;
		18	$cv->send;
43	);	19	};
44		20
45	$cv->wait;	21	# send some request line
		22	$hdl->push_write ("getinfo\015\012");
		23
		24	# read the response line
		25	$hdl->push_read (line => sub {
		26	my ($hdl, $line) = @_;
		27	warn "got line <$line>\n";
		28	$cv->send;
		29	});
		30
		31	$cv->recv;
46		32
47	=head1 DESCRIPTION	33	=head1 DESCRIPTION
48		34
49	This module is a helper module to make it easier to do event-based I/O on	35	This is a helper module to make it easier to do event-based I/O on
50	filehandles. For utility functions for doing non-blocking connects and accepts	36	stream-based filehandles (sockets, pipes, and other stream things).
51	on sockets see L<AnyEvent::Util>.
52		37
		38	The L<AnyEvent::Intro> tutorial contains some well-documented
		39	AnyEvent::Handle examples.
		40
53	In the following, when the documentation refers to of "bytes" then this	41	In the following, where the documentation refers to "bytes", it means
54	means characters. As sysread and syswrite are used for all I/O, their	42	characters. As sysread and syswrite are used for all I/O, their
55	treatment of characters applies to this module as well.	43	treatment of characters applies to this module as well.
		44
		45	At the very minimum, you should specify C<fh> or C<connect>, and the
		46	C<on_error> callback.
56		47
57	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
58	argument.	49	argument.
59		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
60	=head1 METHODS	80	=head1 METHODS
61		81
62	=over 4	82	=over 4
63		83
64	=item B<new (%args)>	84	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
65		85
66	The constructor supports these arguments (all as key => value pairs).	86	The constructor supports these arguments (all as C<< key => value >> pairs).
67		87
68	=over 4	88	=over 4
69		89
70	=item fh => $filehandle [MANDATORY]	90	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
71		91
72	The filehandle this L<AnyEvent::Handle> object will operate on.	92	The filehandle this L<AnyEvent::Handle> object will operate on.
73
74	NOTE: The filehandle will be set to non-blocking (using	93	NOTE: The filehandle will be set to non-blocking mode (using
75	AnyEvent::Util::fh_nonblocking).	94	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		95	that mode.
76		96
77	=item on_eof => $cb->($self)	97	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
78		98
79	Set the callback to be called on EOF.	99	Try to connect to the specified host and service (port), using
		100	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		101	default C<peername>.
80		102
81	While not mandatory, it is highly recommended to set an eof callback,	103	You have to specify either this parameter, or C<fh>, above.
82	otherwise you might end up with a closed socket while you are still
83	waiting for data.
84		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
85	=item on_error => $cb->($self)	114	=item on_prepare => $cb->($handle)
86		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 that the
		124	default timeout is to be used).
		125
		126	=item on_connect => $cb->($handle, $host, $port, $retry->())
		127
		128	This callback is called when a connection has been successfully established.
		129
		130	The peer's numeric host and port (the socket peername) are passed as
		131	parameters, together with a retry callback.
		132
		133	If, for some reason, the handle is not acceptable, calling C<$retry>
		134	will continue with the next connection target (in case of multi-homed
		135	hosts or SRV records there can be multiple connection endpoints). At the
		136	time it is called the read and write queues, eof status, tls status and
		137	similar properties of the handle will have been reset.
		138
		139	In most cases, you should ignore the C<$retry> parameter.
		140
		141	=item on_connect_error => $cb->($handle, $message)
		142
		143	This callback is called when the connection could not be
		144	established. C<$!> will contain the relevant error code, and C<$message> a
		145	message describing it (usually the same as C<"$!">).
		146
		147	If this callback isn't specified, then C<on_error> will be called with a
		148	fatal error instead.
		149
		150	=back
		151
		152	=item on_error => $cb->($handle, $fatal, $message)
		153
87	This is the fatal error callback, that is called when, well, a fatal error	154	This is the error callback, which is called when, well, some error
88	occurs, such as not being able to resolve the hostname, failure to connect	155	occured, such as not being able to resolve the hostname, failure to
89	or a read error.	156	connect, or a read error.
90		157
91	The object will not be in a usable state when this callback has been	158	Some errors are fatal (which is indicated by C<$fatal> being true). On
92	called.	159	fatal errors the handle object will be destroyed (by a call to C<< ->
		160	destroy >>) after invoking the error callback (which means you are free to
		161	examine the handle object). Examples of fatal errors are an EOF condition
		162	with active (but unsatisifable) read watchers (C<EPIPE>) or I/O errors. In
		163	cases where the other side can close the connection at will, it is
		164	often easiest to not report C<EPIPE> errors in this callback.
93		165
		166	AnyEvent::Handle tries to find an appropriate error code for you to check
		167	against, but in some cases (TLS errors), this does not work well. It is
		168	recommended to always output the C<$message> argument in human-readable
		169	error messages (it's usually the same as C<"$!">).
		170
		171	Non-fatal errors can be retried by returning, but it is recommended
		172	to simply ignore this parameter and instead abondon the handle object
		173	when this callback is invoked. Examples of non-fatal errors are timeouts
		174	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		175
94	On callback entrance, the value of C<$!> contains the operating system	176	On entry to the callback, the value of C<$!> contains the operating
95	error (or C<ENOSPC>, C<EPIPE> or C<EBADMSG>).	177	system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		178	C<EPROTO>).
96		179
97	While not mandatory, it is I<highly> recommended to set this callback, as	180	While not mandatory, it is I<highly> recommended to set this callback, as
98	you will not be notified of errors otherwise. The default simply calls	181	you will not be notified of errors otherwise. The default just calls
99	die.	182	C<croak>.
100		183
101	=item on_read => $cb->($self)	184	=item on_read => $cb->($handle)
102		185
103	This sets the default read callback, which is called when data arrives	186	This sets the default read callback, which is called when data arrives
104	and no read request is in the queue.	187	and no read request is in the queue (unlike read queue callbacks, this
		188	callback will only be called when at least one octet of data is in the
		189	read buffer).
105		190
106	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	191	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
107	method or access the C<$self->{rbuf}> member directly.	192	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		193	must not enlarge or modify the read buffer, you can only remove data at
		194	the beginning from it.
108		195
		196	You can also call C<< ->push_read (...) >> or any other function that
		197	modifies the read queue. Or do both. Or ...
		198
109	When an EOF condition is detected then AnyEvent::Handle will first try to	199	When an EOF condition is detected, AnyEvent::Handle will first try to
110	feed all the remaining data to the queued callbacks and C<on_read> before	200	feed all the remaining data to the queued callbacks and C<on_read> before
111	calling the C<on_eof> callback. If no progress can be made, then a fatal	201	calling the C<on_eof> callback. If no progress can be made, then a fatal
112	error will be raised (with C<$!> set to C<EPIPE>).	202	error will be raised (with C<$!> set to C<EPIPE>).
113		203
		204	Note that, unlike requests in the read queue, an C<on_read> callback
		205	doesn't mean you I<require> some data: if there is an EOF and there
		206	are outstanding read requests then an error will be flagged. With an
		207	C<on_read> callback, the C<on_eof> callback will be invoked.
		208
		209	=item on_eof => $cb->($handle)
		210
		211	Set the callback to be called when an end-of-file condition is detected,
		212	i.e. in the case of a socket, when the other side has closed the
		213	connection cleanly, and there are no outstanding read requests in the
		214	queue (if there are read requests, then an EOF counts as an unexpected
		215	connection close and will be flagged as an error).
		216
		217	For sockets, this just means that the other side has stopped sending data,
		218	you can still try to write data, and, in fact, one can return from the EOF
		219	callback and continue writing data, as only the read part has been shut
		220	down.
		221
		222	If an EOF condition has been detected but no C<on_eof> callback has been
		223	set, then a fatal error will be raised with C<$!> set to <0>.
		224
114	=item on_drain => $cb->()	225	=item on_drain => $cb->($handle)
115		226
116	This sets the callback that is called when the write buffer becomes empty	227	This sets the callback that is called when the write buffer becomes empty
117	(or when the callback is set and the buffer is empty already).	228	(or immediately if the buffer is empty already).
118		229
119	To append to the write buffer, use the C<< ->push_write >> method.	230	To append to the write buffer, use the C<< ->push_write >> method.
		231
		232	This callback is useful when you don't want to put all of your write data
		233	into the queue at once, for example, when you want to write the contents
		234	of some file to the socket you might not want to read the whole file into
		235	memory and push it into the queue, but instead only read more data from
		236	the file when the write queue becomes empty.
		237
		238	=item timeout => $fractional_seconds
		239
		240	=item rtimeout => $fractional_seconds
		241
		242	=item wtimeout => $fractional_seconds
		243
		244	If non-zero, then these enables an "inactivity" timeout: whenever this
		245	many seconds pass without a successful read or write on the underlying
		246	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
		247	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		248	error will be raised).
		249
		250	There are three variants of the timeouts that work independently
		251	of each other, for both read and write, just read, and just write:
		252	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		253	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		254	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		255
		256	Note that timeout processing is active even when you do not have
		257	any outstanding read or write requests: If you plan to keep the connection
		258	idle then you should disable the timeout temporarily or ignore the timeout
		259	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		260	restart the timeout.
		261
		262	Zero (the default) disables this timeout.
		263
		264	=item on_timeout => $cb->($handle)
		265
		266	Called whenever the inactivity timeout passes. If you return from this
		267	callback, then the timeout will be reset as if some activity had happened,
		268	so this condition is not fatal in any way.
120		269
121	=item rbuf_max => <bytes>	270	=item rbuf_max => <bytes>
122		271
123	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	272	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
124	when the read buffer ever (strictly) exceeds this size. This is useful to	273	when the read buffer ever (strictly) exceeds this size. This is useful to
125	avoid denial-of-service attacks.	274	avoid some forms of denial-of-service attacks.
126		275
127	For example, a server accepting connections from untrusted sources should	276	For example, a server accepting connections from untrusted sources should
128	be configured to accept only so-and-so much data that it cannot act on	277	be configured to accept only so-and-so much data that it cannot act on
129	(for example, when expecting a line, an attacker could send an unlimited	278	(for example, when expecting a line, an attacker could send an unlimited
130	amount of data without a callback ever being called as long as the line	279	amount of data without a callback ever being called as long as the line
131	isn't finished).	280	isn't finished).
132		281
		282	=item autocork => <boolean>
		283
		284	When disabled (the default), C<push_write> will try to immediately
		285	write the data to the handle if possible. This avoids having to register
		286	a write watcher and wait for the next event loop iteration, but can
		287	be inefficient if you write multiple small chunks (on the wire, this
		288	disadvantage is usually avoided by your kernel's nagle algorithm, see
		289	C<no_delay>, but this option can save costly syscalls).
		290
		291	When enabled, writes will always be queued till the next event loop
		292	iteration. This is efficient when you do many small writes per iteration,
		293	but less efficient when you do a single write only per iteration (or when
		294	the write buffer often is full). It also increases write latency.
		295
		296	=item no_delay => <boolean>
		297
		298	When doing small writes on sockets, your operating system kernel might
		299	wait a bit for more data before actually sending it out. This is called
		300	the Nagle algorithm, and usually it is beneficial.
		301
		302	In some situations you want as low a delay as possible, which can be
		303	accomplishd by setting this option to a true value.
		304
		305	The default is your operating system's default behaviour (most likely
		306	enabled). This option explicitly enables or disables it, if possible.
		307
		308	=item keepalive => <boolean>
		309
		310	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		311	normally, TCP connections have no time-out once established, so TCP
		312	connections, once established, can stay alive forever even when the other
		313	side has long gone. TCP keepalives are a cheap way to take down long-lived
		314	TCP connections when the other side becomes unreachable. While the default
		315	is OS-dependent, TCP keepalives usually kick in after around two hours,
		316	and, if the other side doesn't reply, take down the TCP connection some 10
		317	to 15 minutes later.
		318
		319	It is harmless to specify this option for file handles that do not support
		320	keepalives, and enabling it on connections that are potentially long-lived
		321	is usually a good idea.
		322
		323	=item oobinline => <boolean>
		324
		325	BSD majorly fucked up the implementation of TCP urgent data. The result
		326	is that almost no OS implements TCP according to the specs, and every OS
		327	implements it slightly differently.
		328
		329	If you want to handle TCP urgent data, then setting this flag (the default
		330	is enabled) gives you the most portable way of getting urgent data, by
		331	putting it into the stream.
		332
		333	Since BSD emulation of OOB data on top of TCP's urgent data can have
		334	security implications, AnyEvent::Handle sets this flag automatically
		335	unless explicitly specified. Note that setting this flag after
		336	establishing a connection I<may> be a bit too late (data loss could
		337	already have occured on BSD systems), but at least it will protect you
		338	from most attacks.
		339
133	=item read_size => <bytes>	340	=item read_size => <bytes>
134		341
135	The default read block size (the amount of bytes this module will try to read	342	The default read block size (the number of bytes this module will
136	on each [loop iteration). Default: C<4096>.	343	try to read during each loop iteration, which affects memory
		344	requirements). Default: C<8192>.
137		345
138	=item low_water_mark => <bytes>	346	=item low_water_mark => <bytes>
139		347
140	Sets the amount of bytes (default: C<0>) that make up an "empty" write	348	Sets the number of bytes (default: C<0>) that make up an "empty" write
141	buffer: If the write reaches this size or gets even samller it is	349	buffer: If the buffer reaches this size or gets even samller it is
142	considered empty.	350	considered empty.
143		351
		352	Sometimes it can be beneficial (for performance reasons) to add data to
		353	the write buffer before it is fully drained, but this is a rare case, as
		354	the operating system kernel usually buffers data as well, so the default
		355	is good in almost all cases.
		356
		357	=item linger => <seconds>
		358
		359	If this is non-zero (default: C<3600>), the destructor of the
		360	AnyEvent::Handle object will check whether there is still outstanding
		361	write data and will install a watcher that will write this data to the
		362	socket. No errors will be reported (this mostly matches how the operating
		363	system treats outstanding data at socket close time).
		364
		365	This will not work for partial TLS data that could not be encoded
		366	yet. This data will be lost. Calling the C<stoptls> method in time might
		367	help.
		368
		369	=item peername => $string
		370
		371	A string used to identify the remote site - usually the DNS hostname
		372	(I<not> IDN!) used to create the connection, rarely the IP address.
		373
		374	Apart from being useful in error messages, this string is also used in TLS
		375	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		376	verification will be skipped when C<peername> is not specified or is
		377	C<undef>.
		378
144	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	379	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
145		380
146	When this parameter is given, it enables TLS (SSL) mode, that means it	381	When this parameter is given, it enables TLS (SSL) mode, that means
147	will start making tls handshake and will transparently encrypt/decrypt	382	AnyEvent will start a TLS handshake as soon as the connection has been
148	data.	383	established and will transparently encrypt/decrypt data afterwards.
		384
		385	All TLS protocol errors will be signalled as C<EPROTO>, with an
		386	appropriate error message.
149		387
150	TLS mode requires Net::SSLeay to be installed (it will be loaded	388	TLS mode requires Net::SSLeay to be installed (it will be loaded
151	automatically when you try to create a TLS handle).	389	automatically when you try to create a TLS handle): this module doesn't
		390	have a dependency on that module, so if your module requires it, you have
		391	to add the dependency yourself.
152		392
153	For the TLS server side, use C<accept>, and for the TLS client side of a	393	Unlike TCP, TLS has a server and client side: for the TLS server side, use
154	connection, use C<connect> mode.	394	C<accept>, and for the TLS client side of a connection, use C<connect>
		395	mode.
155		396
156	You can also provide your own TLS connection object, but you have	397	You can also provide your own TLS connection object, but you have
157	to make sure that you call either C<Net::SSLeay::set_connect_state>	398	to make sure that you call either C<Net::SSLeay::set_connect_state>
158	or C<Net::SSLeay::set_accept_state> on it before you pass it to	399	or C<Net::SSLeay::set_accept_state> on it before you pass it to
159	AnyEvent::Handle.	400	AnyEvent::Handle. Also, this module will take ownership of this connection
		401	object.
160		402
		403	At some future point, AnyEvent::Handle might switch to another TLS
		404	implementation, then the option to use your own session object will go
		405	away.
		406
		407	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		408	passing in the wrong integer will lead to certain crash. This most often
		409	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		410	segmentation fault.
		411
161	See the C<starttls> method if you need to start TLs negotiation later.	412	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
162		413
163	=item tls_ctx => $ssl_ctx	414	=item tls_ctx => $anyevent_tls
164		415
165	Use the given Net::SSLeay::CTX object to create the new TLS connection	416	Use the given C<AnyEvent::TLS> object to create the new TLS connection
166	(unless a connection object was specified directly). If this parameter is	417	(unless a connection object was specified directly). If this parameter is
167	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	418	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
168		419
		420	Instead of an object, you can also specify a hash reference with C<< key
		421	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		422	new TLS context object.
		423
		424	=item on_starttls => $cb->($handle, $success[, $error_message])
		425
		426	This callback will be invoked when the TLS/SSL handshake has finished. If
		427	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		428	(C<on_stoptls> will not be called in this case).
		429
		430	The session in C<< $handle->{tls} >> can still be examined in this
		431	callback, even when the handshake was not successful.
		432
		433	TLS handshake failures will not cause C<on_error> to be invoked when this
		434	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		435
		436	Without this callback, handshake failures lead to C<on_error> being
		437	called as usual.
		438
		439	Note that you cannot just call C<starttls> again in this callback. If you
		440	need to do that, start an zero-second timer instead whose callback can
		441	then call C<< ->starttls >> again.
		442
		443	=item on_stoptls => $cb->($handle)
		444
		445	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		446	set, then it will be invoked after freeing the TLS session. If it is not,
		447	then a TLS shutdown condition will be treated like a normal EOF condition
		448	on the handle.
		449
		450	The session in C<< $handle->{tls} >> can still be examined in this
		451	callback.
		452
		453	This callback will only be called on TLS shutdowns, not when the
		454	underlying handle signals EOF.
		455
		456	=item json => JSON or JSON::XS object
		457
		458	This is the json coder object used by the C<json> read and write types.
		459
		460	If you don't supply it, then AnyEvent::Handle will create and use a
		461	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		462	texts.
		463
		464	Note that you are responsible to depend on the JSON module if you want to
		465	use this functionality, as AnyEvent does not have a dependency itself.
		466
169	=back	467	=back
170		468
171	=cut	469	=cut
172		470
173	sub new {	471	sub new {
174	my $class = shift;	472	my $class = shift;
175
176	my $self = bless { @_ }, $class;	473	my $self = bless { @_ }, $class;
177		474
178	$self->{fh} or Carp::croak "mandatory argument fh is missing";	475	if ($self->{fh}) {
		476	$self->_start;
		477	return unless $self->{fh}; # could be gone by now
		478
		479	} elsif ($self->{connect}) {
		480	require AnyEvent::Socket;
		481
		482	$self->{peername} = $self->{connect}[0]
		483	unless exists $self->{peername};
		484
		485	$self->{_skip_drain_rbuf} = 1;
		486
		487	{
		488	Scalar::Util::weaken (my $self = $self);
		489
		490	$self->{_connect} =
		491	AnyEvent::Socket::tcp_connect (
		492	$self->{connect}[0],
		493	$self->{connect}[1],
		494	sub {
		495	my ($fh, $host, $port, $retry) = @_;
		496
		497	if ($fh) {
		498	$self->{fh} = $fh;
		499
		500	delete $self->{_skip_drain_rbuf};
		501	$self->_start;
		502
		503	$self->{on_connect}
		504	and $self->{on_connect}($self, $host, $port, sub {
		505	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		506	$self->{_skip_drain_rbuf} = 1;
		507	&$retry;
		508	});
		509
		510	} else {
		511	if ($self->{on_connect_error}) {
		512	$self->{on_connect_error}($self, "$!");
		513	$self->destroy;
		514	} else {
		515	$self->_error ($!, 1);
		516	}
		517	}
		518	},
		519	sub {
		520	local $self->{fh} = $_[0];
		521
		522	$self->{on_prepare}
		523	? $self->{on_prepare}->($self)
		524	: ()
		525	}
		526	);
		527	}
		528
		529	} else {
		530	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		531	}
		532
		533	$self
		534	}
		535
		536	sub _start {
		537	my ($self) = @_;
		538
		539	# too many clueless people try to use udp and similar sockets
		540	# with AnyEvent::Handle, do them a favour.
		541	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		542	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		543	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
179		544
180	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	545	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
181		546
182	if ($self->{tls}) {	547	$self->{_activity} =
183	require Net::SSLeay;	548	$self->{_ractivity} =
		549	$self->{_wactivity} = AE::now;
		550
		551	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		552	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		553	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		554
		555	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		556	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		557
		558	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		559
184	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	560	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
185	}	561	if $self->{tls};
186		562
187	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
188	$self->on_error (delete $self->{on_error}) if $self->{on_error};
189	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	563	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
190	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
191		564
192	$self->start_read;	565	$self->start_read
		566	if $self->{on_read} || @{ $self->{_queue} };
193		567
194	$self	568	$self->_drain_wbuf;
195	}	569	}
196		570
197	sub _shutdown {
198	my ($self) = @_;
199
200	delete $self->{rw};
201	delete $self->{ww};
202	delete $self->{fh};
203	}
204
205	sub error {	571	sub _error {
206	my ($self) = @_;	572	my ($self, $errno, $fatal, $message) = @_;
207		573
208	{	574	$! = $errno;
209	local $!;	575	$message ||= "$!";
210	$self->_shutdown;
211	}
212		576
213	if ($self->{on_error}) {	577	if ($self->{on_error}) {
214	$self->{on_error}($self);	578	$self->{on_error}($self, $fatal, $message);
215	} else {	579	$self->destroy if $fatal;
		580	} elsif ($self->{fh} || $self->{connect}) {
		581	$self->destroy;
216	Carp::croak "AnyEvent::Handle uncaught fatal error: $!";	582	Carp::croak "AnyEvent::Handle uncaught error: $message";
217	}	583	}
218	}	584	}
219		585
220	=item $fh = $handle->fh	586	=item $fh = $handle->fh
221		587
222	This method returns the file handle of the L<AnyEvent::Handle> object.	588	This method returns the file handle used to create the L<AnyEvent::Handle> object.
223		589
224	=cut	590	=cut
225		591
226	sub fh { $_[0]->{fh} }	592	sub fh { $_[0]{fh} }
227		593
228	=item $handle->on_error ($cb)	594	=item $handle->on_error ($cb)
229		595
230	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	596	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
231		597
…		…
243		609
244	sub on_eof {	610	sub on_eof {
245	$_[0]{on_eof} = $_[1];	611	$_[0]{on_eof} = $_[1];
246	}	612	}
247		613
		614	=item $handle->on_timeout ($cb)
		615
		616	=item $handle->on_rtimeout ($cb)
		617
		618	=item $handle->on_wtimeout ($cb)
		619
		620	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		621	callback, or disables the callback (but not the timeout) if C<$cb> =
		622	C<undef>. See the C<timeout> constructor argument and method.
		623
		624	=cut
		625
		626	# see below
		627
		628	=item $handle->autocork ($boolean)
		629
		630	Enables or disables the current autocork behaviour (see C<autocork>
		631	constructor argument). Changes will only take effect on the next write.
		632
		633	=cut
		634
		635	sub autocork {
		636	$_[0]{autocork} = $_[1];
		637	}
		638
		639	=item $handle->no_delay ($boolean)
		640
		641	Enables or disables the C<no_delay> setting (see constructor argument of
		642	the same name for details).
		643
		644	=cut
		645
		646	sub no_delay {
		647	$_[0]{no_delay} = $_[1];
		648
		649	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		650	if $_[0]{fh};
		651	}
		652
		653	=item $handle->keepalive ($boolean)
		654
		655	Enables or disables the C<keepalive> setting (see constructor argument of
		656	the same name for details).
		657
		658	=cut
		659
		660	sub keepalive {
		661	$_[0]{keepalive} = $_[1];
		662
		663	eval {
		664	local $SIG{__DIE__};
		665	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		666	if $_[0]{fh};
		667	};
		668	}
		669
		670	=item $handle->oobinline ($boolean)
		671
		672	Enables or disables the C<oobinline> setting (see constructor argument of
		673	the same name for details).
		674
		675	=cut
		676
		677	sub oobinline {
		678	$_[0]{oobinline} = $_[1];
		679
		680	eval {
		681	local $SIG{__DIE__};
		682	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		683	if $_[0]{fh};
		684	};
		685	}
		686
		687	=item $handle->keepalive ($boolean)
		688
		689	Enables or disables the C<keepalive> setting (see constructor argument of
		690	the same name for details).
		691
		692	=cut
		693
		694	sub keepalive {
		695	$_[0]{keepalive} = $_[1];
		696
		697	eval {
		698	local $SIG{__DIE__};
		699	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		700	if $_[0]{fh};
		701	};
		702	}
		703
		704	=item $handle->on_starttls ($cb)
		705
		706	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		707
		708	=cut
		709
		710	sub on_starttls {
		711	$_[0]{on_starttls} = $_[1];
		712	}
		713
		714	=item $handle->on_stoptls ($cb)
		715
		716	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		717
		718	=cut
		719
		720	sub on_stoptls {
		721	$_[0]{on_stoptls} = $_[1];
		722	}
		723
		724	=item $handle->rbuf_max ($max_octets)
		725
		726	Configures the C<rbuf_max> setting (C<undef> disables it).
		727
		728	=cut
		729
		730	sub rbuf_max {
		731	$_[0]{rbuf_max} = $_[1];
		732	}
		733
		734	#############################################################################
		735
		736	=item $handle->timeout ($seconds)
		737
		738	=item $handle->rtimeout ($seconds)
		739
		740	=item $handle->wtimeout ($seconds)
		741
		742	Configures (or disables) the inactivity timeout.
		743
		744	=item $handle->timeout_reset
		745
		746	=item $handle->rtimeout_reset
		747
		748	=item $handle->wtimeout_reset
		749
		750	Reset the activity timeout, as if data was received or sent.
		751
		752	These methods are cheap to call.
		753
		754	=cut
		755
		756	for my $dir ("", "r", "w") {
		757	my $timeout = "${dir}timeout";
		758	my $tw = "_${dir}tw";
		759	my $on_timeout = "on_${dir}timeout";
		760	my $activity = "_${dir}activity";
		761	my $cb;
		762
		763	*$on_timeout = sub {
		764	$_[0]{$on_timeout} = $_[1];
		765	};
		766
		767	*$timeout = sub {
		768	my ($self, $new_value) = @_;
		769
		770	$new_value >= 0
		771	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		772
		773	$self->{$timeout} = $new_value;
		774	delete $self->{$tw}; &$cb;
		775	};
		776
		777	*{"${dir}timeout_reset"} = sub {
		778	$_[0]{$activity} = AE::now;
		779	};
		780
		781	# main workhorse:
		782	# reset the timeout watcher, as neccessary
		783	# also check for time-outs
		784	$cb = sub {
		785	my ($self) = @_;
		786
		787	if ($self->{$timeout} && $self->{fh}) {
		788	my $NOW = AE::now;
		789
		790	# when would the timeout trigger?
		791	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		792
		793	# now or in the past already?
		794	if ($after <= 0) {
		795	$self->{$activity} = $NOW;
		796
		797	if ($self->{$on_timeout}) {
		798	$self->{$on_timeout}($self);
		799	} else {
		800	$self->_error (Errno::ETIMEDOUT);
		801	}
		802
		803	# callback could have changed timeout value, optimise
		804	return unless $self->{$timeout};
		805
		806	# calculate new after
		807	$after = $self->{$timeout};
		808	}
		809
		810	Scalar::Util::weaken $self;
		811	return unless $self; # ->error could have destroyed $self
		812
		813	$self->{$tw} ||= AE::timer $after, 0, sub {
		814	delete $self->{$tw};
		815	$cb->($self);
		816	};
		817	} else {
		818	delete $self->{$tw};
		819	}
		820	}
		821	}
		822
248	#############################################################################	823	#############################################################################
249		824
250	=back	825	=back
251		826
252	=head2 WRITE QUEUE	827	=head2 WRITE QUEUE
…		…
265	=item $handle->on_drain ($cb)	840	=item $handle->on_drain ($cb)
266		841
267	Sets the C<on_drain> callback or clears it (see the description of	842	Sets the C<on_drain> callback or clears it (see the description of
268	C<on_drain> in the constructor).	843	C<on_drain> in the constructor).
269		844
		845	This method may invoke callbacks (and therefore the handle might be
		846	destroyed after it returns).
		847
270	=cut	848	=cut
271		849
272	sub on_drain {	850	sub on_drain {
273	my ($self, $cb) = @_;	851	my ($self, $cb) = @_;
274		852
275	$self->{on_drain} = $cb;	853	$self->{on_drain} = $cb;
276		854
277	$cb->($self)	855	$cb->($self)
278	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	856	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
279	}	857	}
280		858
281	=item $handle->push_write ($data)	859	=item $handle->push_write ($data)
282		860
283	Queues the given scalar to be written. You can push as much data as you	861	Queues the given scalar to be written. You can push as much data as you
284	want (only limited by the available memory), as C<AnyEvent::Handle>	862	want (only limited by the available memory), as C<AnyEvent::Handle>
285	buffers it independently of the kernel.	863	buffers it independently of the kernel.
286		864
		865	This method may invoke callbacks (and therefore the handle might be
		866	destroyed after it returns).
		867
287	=cut	868	=cut
288		869
289	sub _drain_wbuf {	870	sub _drain_wbuf {
290	my ($self) = @_;	871	my ($self) = @_;
291		872
292	if (!$self->{ww} && length $self->{wbuf}) {	873	if (!$self->{_ww} && length $self->{wbuf}) {
		874
293	Scalar::Util::weaken $self;	875	Scalar::Util::weaken $self;
		876
294	my $cb = sub {	877	my $cb = sub {
295	my $len = syswrite $self->{fh}, $self->{wbuf};	878	my $len = syswrite $self->{fh}, $self->{wbuf};
296		879
297	if ($len >= 0) {	880	if (defined $len) {
298	substr $self->{wbuf}, 0, $len, "";	881	substr $self->{wbuf}, 0, $len, "";
299		882
		883	$self->{_activity} = $self->{_wactivity} = AE::now;
		884
300	$self->{on_drain}($self)	885	$self->{on_drain}($self)
301	if $self->{low_water_mark} >= length $self->{wbuf}	886	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
302	&& $self->{on_drain};	887	&& $self->{on_drain};
303		888
304	delete $self->{ww} unless length $self->{wbuf};	889	delete $self->{_ww} unless length $self->{wbuf};
305	} elsif ($! != EAGAIN && $! != EINTR) {	890	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
306	$self->error;	891	$self->_error ($!, 1);
307	}	892	}
308	};	893	};
309		894
310	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	895	# try to write data immediately
		896	$cb->() unless $self->{autocork};
311		897
312	$cb->($self);	898	# if still data left in wbuf, we need to poll
		899	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		900	if length $self->{wbuf};
313	};	901	};
314	}	902	}
315		903
316	our %WH;	904	our %WH;
317		905
		906	# deprecated
318	sub register_write_type($$) {	907	sub register_write_type($$) {
319	$WH{$_[0]} = $_[1];	908	$WH{$_[0]} = $_[1];
320	}	909	}
321		910
322	sub push_write {	911	sub push_write {
323	my $self = shift;	912	my $self = shift;
324		913
325	if (@_ > 1) {	914	if (@_ > 1) {
326	my $type = shift;	915	my $type = shift;
327		916
		917	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
328	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	918	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
329	->($self, @_);	919	->($self, @_);
330	}	920	}
331		921
		922	# we downgrade here to avoid hard-to-track-down bugs,
		923	# and diagnose the problem earlier and better.
		924
332	if ($self->{filter_w}) {	925	if ($self->{tls}) {
333	$self->{filter_w}->($self, \$_[0]);	926	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		927	&_dotls ($self) if $self->{fh};
334	} else {	928	} else {
335	$self->{wbuf} .= $_[0];	929	utf8::downgrade $self->{wbuf} .= $_[0];
336	$self->_drain_wbuf;	930	$self->_drain_wbuf if $self->{fh};
337	}	931	}
338	}	932	}
339		933
340	=item $handle->push_write (type => @args)	934	=item $handle->push_write (type => @args)
341		935
342	=item $handle->unshift_write (type => @args)
343
344	Instead of formatting your data yourself, you can also let this module do	936	Instead of formatting your data yourself, you can also let this module
345	the job by specifying a type and type-specific arguments.	937	do the job by specifying a type and type-specific arguments. You
		938	can also specify the (fully qualified) name of a package, in which
		939	case AnyEvent tries to load the package and then expects to find the
		940	C<anyevent_write_type> function inside (see "custom write types", below).
346		941
347	Predefined types are (if you have ideas for additional types, feel free to	942	Predefined types are (if you have ideas for additional types, feel free to
348	drop by and tell us):	943	drop by and tell us):
349		944
350	=over 4	945	=over 4
…		…
352	=item netstring => $string	947	=item netstring => $string
353		948
354	Formats the given value as netstring	949	Formats the given value as netstring
355	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).	950	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
356		951
357	=back
358
359	=cut	952	=cut
360		953
361	register_write_type netstring => sub {	954	register_write_type netstring => sub {
362	my ($self, $string) = @_;	955	my ($self, $string) = @_;
363		956
364	sprintf "%d:%s,", (length $string), $string	957	(length $string) . ":$string,"
365	};	958	};
366		959
367	=item AnyEvent::Handle::register_write_type type => $coderef->($self, @args)	960	=item packstring => $format, $data
368		961
369	This function (not method) lets you add your own types to C<push_write>.	962	An octet string prefixed with an encoded length. The encoding C<$format>
		963	uses the same format as a Perl C<pack> format, but must specify a single
		964	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		965	optional C<!>, C<< < >> or C<< > >> modifier).
		966
		967	=cut
		968
		969	register_write_type packstring => sub {
		970	my ($self, $format, $string) = @_;
		971
		972	pack "$format/a*", $string
		973	};
		974
		975	=item json => $array_or_hashref
		976
		977	Encodes the given hash or array reference into a JSON object. Unless you
		978	provide your own JSON object, this means it will be encoded to JSON text
		979	in UTF-8.
		980
		981	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		982	one end of a handle and read them at the other end without using any
		983	additional framing.
		984
		985	The generated JSON text is guaranteed not to contain any newlines: While
		986	this module doesn't need delimiters after or between JSON texts to be
		987	able to read them, many other languages depend on that.
		988
		989	A simple RPC protocol that interoperates easily with others is to send
		990	JSON arrays (or objects, although arrays are usually the better choice as
		991	they mimic how function argument passing works) and a newline after each
		992	JSON text:
		993
		994	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		995	$handle->push_write ("\012");
		996
		997	An AnyEvent::Handle receiver would simply use the C<json> read type and
		998	rely on the fact that the newline will be skipped as leading whitespace:
		999
		1000	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1001
		1002	Other languages could read single lines terminated by a newline and pass
		1003	this line into their JSON decoder of choice.
		1004
		1005	=cut
		1006
		1007	sub json_coder() {
		1008	eval { require JSON::XS; JSON::XS->new->utf8 }
		1009	|| do { require JSON; JSON->new->utf8 }
		1010	}
		1011
		1012	register_write_type json => sub {
		1013	my ($self, $ref) = @_;
		1014
		1015	my $json = $self->{json} ||= json_coder;
		1016
		1017	$json->encode ($ref)
		1018	};
		1019
		1020	=item storable => $reference
		1021
		1022	Freezes the given reference using L<Storable> and writes it to the
		1023	handle. Uses the C<nfreeze> format.
		1024
		1025	=cut
		1026
		1027	register_write_type storable => sub {
		1028	my ($self, $ref) = @_;
		1029
		1030	require Storable;
		1031
		1032	pack "w/a*", Storable::nfreeze ($ref)
		1033	};
		1034
		1035	=back
		1036
		1037	=item $handle->push_shutdown
		1038
		1039	Sometimes you know you want to close the socket after writing your data
		1040	before it was actually written. One way to do that is to replace your
		1041	C<on_drain> handler by a callback that shuts down the socket (and set
		1042	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1043	replaces the C<on_drain> callback with:
		1044
		1045	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		1046
		1047	This simply shuts down the write side and signals an EOF condition to the
		1048	the peer.
		1049
		1050	You can rely on the normal read queue and C<on_eof> handling
		1051	afterwards. This is the cleanest way to close a connection.
		1052
		1053	This method may invoke callbacks (and therefore the handle might be
		1054	destroyed after it returns).
		1055
		1056	=cut
		1057
		1058	sub push_shutdown {
		1059	my ($self) = @_;
		1060
		1061	delete $self->{low_water_mark};
		1062	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1063	}
		1064
		1065	=item custom write types - Package::anyevent_write_type $handle, @args
		1066
		1067	Instead of one of the predefined types, you can also specify the name of
		1068	a package. AnyEvent will try to load the package and then expects to find
		1069	a function named C<anyevent_write_type> inside. If it isn't found, it
		1070	progressively tries to load the parent package until it either finds the
		1071	function (good) or runs out of packages (bad).
		1072
370	Whenever the given C<type> is used, C<push_write> will invoke the code	1073	Whenever the given C<type> is used, C<push_write> will the function with
371	reference with the handle object and the remaining arguments.	1074	the handle object and the remaining arguments.
372		1075
373	The code reference is supposed to return a single octet string that will	1076	The function is supposed to return a single octet string that will be
374	be appended to the write buffer.	1077	appended to the write buffer, so you cna mentally treat this function as a
		1078	"arguments to on-the-wire-format" converter.
375		1079
376	Note that this is a function, and all types registered this way will be	1080	Example: implement a custom write type C<join> that joins the remaining
377	global, so try to use unique names.	1081	arguments using the first one.
		1082
		1083	$handle->push_write (My::Type => " ", 1,2,3);
		1084
		1085	# uses the following package, which can be defined in the "My::Type" or in
		1086	# the "My" modules to be auto-loaded, or just about anywhere when the
		1087	# My::Type::anyevent_write_type is defined before invoking it.
		1088
		1089	package My::Type;
		1090
		1091	sub anyevent_write_type {
		1092	my ($handle, $delim, @args) = @_;
		1093
		1094	join $delim, @args
		1095	}
378		1096
379	=cut	1097	=cut
380		1098
381	#############################################################################	1099	#############################################################################
382		1100
…		…
391	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1109	ways, the "simple" way, using only C<on_read> and the "complex" way, using
392	a queue.	1110	a queue.
393		1111
394	In the simple case, you just install an C<on_read> callback and whenever	1112	In the simple case, you just install an C<on_read> callback and whenever
395	new data arrives, it will be called. You can then remove some data (if	1113	new data arrives, it will be called. You can then remove some data (if
396	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1114	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
397	or not.	1115	leave the data there if you want to accumulate more (e.g. when only a
		1116	partial message has been received so far), or change the read queue with
		1117	e.g. C<push_read>.
398		1118
399	In the more complex case, you want to queue multiple callbacks. In this	1119	In the more complex case, you want to queue multiple callbacks. In this
400	case, AnyEvent::Handle will call the first queued callback each time new	1120	case, AnyEvent::Handle will call the first queued callback each time new
401	data arrives and removes it when it has done its job (see C<push_read>,	1121	data arrives (also the first time it is queued) and remove it when it has
402	below).	1122	done its job (see C<push_read>, below).
403		1123
404	This way you can, for example, push three line-reads, followed by reading	1124	This way you can, for example, push three line-reads, followed by reading
405	a chunk of data, and AnyEvent::Handle will execute them in order.	1125	a chunk of data, and AnyEvent::Handle will execute them in order.
406		1126
407	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1127	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
408	the specified number of bytes which give an XML datagram.	1128	the specified number of bytes which give an XML datagram.
409		1129
410	# in the default state, expect some header bytes	1130	# in the default state, expect some header bytes
411	$handle->on_read (sub {	1131	$handle->on_read (sub {
412	# some data is here, now queue the length-header-read (4 octets)	1132	# some data is here, now queue the length-header-read (4 octets)
413	shift->unshift_read_chunk (4, sub {	1133	shift->unshift_read (chunk => 4, sub {
414	# header arrived, decode	1134	# header arrived, decode
415	my $len = unpack "N", $_[1];	1135	my $len = unpack "N", $_[1];
416		1136
417	# now read the payload	1137	# now read the payload
418	shift->unshift_read_chunk ($len, sub {	1138	shift->unshift_read (chunk => $len, sub {
419	my $xml = $_[1];	1139	my $xml = $_[1];
420	# handle xml	1140	# handle xml
421	});	1141	});
422	});	1142	});
423	});	1143	});
424		1144
425	Example 2: Implement a client for a protocol that replies either with	1145	Example 2: Implement a client for a protocol that replies either with "OK"
426	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1146	and another line or "ERROR" for the first request that is sent, and 64
427	second request. Due tot he availability of a full queue, we can just	1147	bytes for the second request. Due to the availability of a queue, we can
428	pipeline sending both requests and manipulate the queue as necessary in	1148	just pipeline sending both requests and manipulate the queue as necessary
429	the callbacks:	1149	in the callbacks.
430		1150
431	# request one	1151	When the first callback is called and sees an "OK" response, it will
		1152	C<unshift> another line-read. This line-read will be queued I<before> the
		1153	64-byte chunk callback.
		1154
		1155	# request one, returns either "OK + extra line" or "ERROR"
432	$handle->push_write ("request 1\015\012");	1156	$handle->push_write ("request 1\015\012");
433		1157
434	# we expect "ERROR" or "OK" as response, so push a line read	1158	# we expect "ERROR" or "OK" as response, so push a line read
435	$handle->push_read_line (sub {	1159	$handle->push_read (line => sub {
436	# if we got an "OK", we have to _prepend_ another line,	1160	# if we got an "OK", we have to _prepend_ another line,
437	# so it will be read before the second request reads its 64 bytes	1161	# so it will be read before the second request reads its 64 bytes
438	# which are already in the queue when this callback is called	1162	# which are already in the queue when this callback is called
439	# we don't do this in case we got an error	1163	# we don't do this in case we got an error
440	if ($_[1] eq "OK") {	1164	if ($_[1] eq "OK") {
441	$_[0]->unshift_read_line (sub {	1165	$_[0]->unshift_read (line => sub {
442	my $response = $_[1];	1166	my $response = $_[1];
443	...	1167	...
444	});	1168	});
445	}	1169	}
446	});	1170	});
447		1171
448	# request two	1172	# request two, simply returns 64 octets
449	$handle->push_write ("request 2\015\012");	1173	$handle->push_write ("request 2\015\012");
450		1174
451	# simply read 64 bytes, always	1175	# simply read 64 bytes, always
452	$handle->push_read_chunk (64, sub {	1176	$handle->push_read (chunk => 64, sub {
453	my $response = $_[1];	1177	my $response = $_[1];
454	...	1178	...
455	});	1179	});
456		1180
457	=over 4	1181	=over 4
458		1182
459	=cut	1183	=cut
460		1184
461	sub _drain_rbuf {	1185	sub _drain_rbuf {
462	my ($self) = @_;	1186	my ($self) = @_;
		1187
		1188	# avoid recursion
		1189	return if $self->{_skip_drain_rbuf};
		1190	local $self->{_skip_drain_rbuf} = 1;
		1191
		1192	while () {
		1193	# we need to use a separate tls read buffer, as we must not receive data while
		1194	# we are draining the buffer, and this can only happen with TLS.
		1195	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1196	if exists $self->{_tls_rbuf};
		1197
		1198	my $len = length $self->{rbuf};
		1199
		1200	if (my $cb = shift @{ $self->{_queue} }) {
		1201	unless ($cb->($self)) {
		1202	# no progress can be made
		1203	# (not enough data and no data forthcoming)
		1204	$self->_error (Errno::EPIPE, 1), return
		1205	if $self->{_eof};
		1206
		1207	unshift @{ $self->{_queue} }, $cb;
		1208	last;
		1209	}
		1210	} elsif ($self->{on_read}) {
		1211	last unless $len;
		1212
		1213	$self->{on_read}($self);
		1214
		1215	if (
		1216	$len == length $self->{rbuf} # if no data has been consumed
		1217	&& !@{ $self->{_queue} } # and the queue is still empty
		1218	&& $self->{on_read} # but we still have on_read
		1219	) {
		1220	# no further data will arrive
		1221	# so no progress can be made
		1222	$self->_error (Errno::EPIPE, 1), return
		1223	if $self->{_eof};
		1224
		1225	last; # more data might arrive
		1226	}
		1227	} else {
		1228	# read side becomes idle
		1229	delete $self->{_rw} unless $self->{tls};
		1230	last;
		1231	}
		1232	}
		1233
		1234	if ($self->{_eof}) {
		1235	$self->{on_eof}
		1236	? $self->{on_eof}($self)
		1237	: $self->_error (0, 1, "Unexpected end-of-file");
		1238
		1239	return;
		1240	}
463		1241
464	if (	1242	if (
465	defined $self->{rbuf_max}	1243	defined $self->{rbuf_max}
466	&& $self->{rbuf_max} < length $self->{rbuf}	1244	&& $self->{rbuf_max} < length $self->{rbuf}
467	) {	1245	) {
468	$! = &Errno::ENOSPC; return $self->error;	1246	$self->_error (Errno::ENOSPC, 1), return;
469	}	1247	}
470		1248
471	return if $self->{in_drain};	1249	# may need to restart read watcher
472	local $self->{in_drain} = 1;	1250	unless ($self->{_rw}) {
473		1251	$self->start_read
474	while (my $len = length $self->{rbuf}) {	1252	if $self->{on_read} || @{ $self->{_queue} };
475	no strict 'refs';
476	if (my $cb = shift @{ $self->{queue} }) {
477	unless ($cb->($self)) {
478	if ($self->{eof}) {
479	# no progress can be made (not enough data and no data forthcoming)
480	$! = &Errno::EPIPE; return $self->error;
481	}
482
483	unshift @{ $self->{queue} }, $cb;
484	return;
485	}
486	} elsif ($self->{on_read}) {
487	$self->{on_read}($self);
488
489	if (
490	$self->{eof} # if no further data will arrive
491	&& $len == length $self->{rbuf} # and no data has been consumed
492	&& !@{ $self->{queue} } # and the queue is still empty
493	&& $self->{on_read} # and we still want to read data
494	) {
495	# then no progress can be made
496	$! = &Errno::EPIPE; return $self->error;
497	}
498	} else {
499	# read side becomes idle
500	delete $self->{rw};
501	return;
502	}
503	}
504
505	if ($self->{eof}) {
506	$self->_shutdown;
507	$self->{on_eof}($self)
508	if $self->{on_eof};
509	}	1253	}
510	}	1254	}
511		1255
512	=item $handle->on_read ($cb)	1256	=item $handle->on_read ($cb)
513		1257
514	This replaces the currently set C<on_read> callback, or clears it (when	1258	This replaces the currently set C<on_read> callback, or clears it (when
515	the new callback is C<undef>). See the description of C<on_read> in the	1259	the new callback is C<undef>). See the description of C<on_read> in the
516	constructor.	1260	constructor.
517		1261
		1262	This method may invoke callbacks (and therefore the handle might be
		1263	destroyed after it returns).
		1264
518	=cut	1265	=cut
519		1266
520	sub on_read {	1267	sub on_read {
521	my ($self, $cb) = @_;	1268	my ($self, $cb) = @_;
522		1269
523	$self->{on_read} = $cb;	1270	$self->{on_read} = $cb;
		1271	$self->_drain_rbuf if $cb;
524	}	1272	}
525		1273
526	=item $handle->rbuf	1274	=item $handle->rbuf
527		1275
528	Returns the read buffer (as a modifiable lvalue).	1276	Returns the read buffer (as a modifiable lvalue). You can also access the
		1277	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1278	much faster, and no less clean).
529		1279
530	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1280	The only operation allowed on the read buffer (apart from looking at it)
531	you want.	1281	is removing data from its beginning. Otherwise modifying or appending to
		1282	it is not allowed and will lead to hard-to-track-down bugs.
532		1283
533	NOTE: The read buffer should only be used or modified if the C<on_read>,	1284	NOTE: The read buffer should only be used or modified in the C<on_read>
534	C<push_read> or C<unshift_read> methods are used. The other read methods	1285	callback or when C<push_read> or C<unshift_read> are used with a single
535	automatically manage the read buffer.	1286	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1287	will manage the read buffer on their own.
536		1288
537	=cut	1289	=cut
538		1290
539	sub rbuf : lvalue {	1291	sub rbuf : lvalue {
540	$_[0]{rbuf}	1292	$_[0]{rbuf}
…		…
557		1309
558	If enough data was available, then the callback must remove all data it is	1310	If enough data was available, then the callback must remove all data it is
559	interested in (which can be none at all) and return a true value. After returning	1311	interested in (which can be none at all) and return a true value. After returning
560	true, it will be removed from the queue.	1312	true, it will be removed from the queue.
561		1313
		1314	These methods may invoke callbacks (and therefore the handle might be
		1315	destroyed after it returns).
		1316
562	=cut	1317	=cut
563		1318
564	our %RH;	1319	our %RH;
565		1320
566	sub register_read_type($$) {	1321	sub register_read_type($$) {
…		…
572	my $cb = pop;	1327	my $cb = pop;
573		1328
574	if (@_) {	1329	if (@_) {
575	my $type = shift;	1330	my $type = shift;
576		1331
		1332	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
577	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	1333	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
578	->($self, $cb, @_);	1334	->($self, $cb, @_);
579	}	1335	}
580		1336
581	push @{ $self->{queue} }, $cb;	1337	push @{ $self->{_queue} }, $cb;
582	$self->_drain_rbuf;	1338	$self->_drain_rbuf;
583	}	1339	}
584		1340
585	sub unshift_read {	1341	sub unshift_read {
586	my $self = shift;	1342	my $self = shift;
587	my $cb = pop;	1343	my $cb = pop;
588		1344
589	if (@_) {	1345	if (@_) {
590	my $type = shift;	1346	my $type = shift;
591		1347
		1348	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
592	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")	1349	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
593	->($self, $cb, @_);	1350	->($self, $cb, @_);
594	}	1351	}
595		1352
596
597	unshift @{ $self->{queue} }, $cb;	1353	unshift @{ $self->{_queue} }, $cb;
598	$self->_drain_rbuf;	1354	$self->_drain_rbuf;
599	}	1355	}
600		1356
601	=item $handle->push_read (type => @args, $cb)	1357	=item $handle->push_read (type => @args, $cb)
602		1358
603	=item $handle->unshift_read (type => @args, $cb)	1359	=item $handle->unshift_read (type => @args, $cb)
604		1360
605	Instead of providing a callback that parses the data itself you can chose	1361	Instead of providing a callback that parses the data itself you can chose
606	between a number of predefined parsing formats, for chunks of data, lines	1362	between a number of predefined parsing formats, for chunks of data, lines
607	etc.	1363	etc. You can also specify the (fully qualified) name of a package, in
		1364	which case AnyEvent tries to load the package and then expects to find the
		1365	C<anyevent_read_type> function inside (see "custom read types", below).
608		1366
609	Predefined types are (if you have ideas for additional types, feel free to	1367	Predefined types are (if you have ideas for additional types, feel free to
610	drop by and tell us):	1368	drop by and tell us):
611		1369
612	=over 4	1370	=over 4
613		1371
614	=item chunk => $octets, $cb->($self, $data)	1372	=item chunk => $octets, $cb->($handle, $data)
615		1373
616	Invoke the callback only once C<$octets> bytes have been read. Pass the	1374	Invoke the callback only once C<$octets> bytes have been read. Pass the
617	data read to the callback. The callback will never be called with less	1375	data read to the callback. The callback will never be called with less
618	data.	1376	data.
619		1377
…		…
633	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1391	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
634	1	1392	1
635	}	1393	}
636	};	1394	};
637		1395
638	# compatibility with older API
639	sub push_read_chunk {
640	$_[0]->push_read (chunk => $_[1], $_[2]);
641	}
642
643	sub unshift_read_chunk {
644	$_[0]->unshift_read (chunk => $_[1], $_[2]);
645	}
646
647	=item line => [$eol, ]$cb->($self, $line, $eol)	1396	=item line => [$eol, ]$cb->($handle, $line, $eol)
648		1397
649	The callback will be called only once a full line (including the end of	1398	The callback will be called only once a full line (including the end of
650	line marker, C<$eol>) has been read. This line (excluding the end of line	1399	line marker, C<$eol>) has been read. This line (excluding the end of line
651	marker) will be passed to the callback as second argument (C<$line>), and	1400	marker) will be passed to the callback as second argument (C<$line>), and
652	the end of line marker as the third argument (C<$eol>).	1401	the end of line marker as the third argument (C<$eol>).
…		…
666	=cut	1415	=cut
667		1416
668	register_read_type line => sub {	1417	register_read_type line => sub {
669	my ($self, $cb, $eol) = @_;	1418	my ($self, $cb, $eol) = @_;
670		1419
671	$eol = qr|(\015?\012)| if @_ < 3;	1420	if (@_ < 3) {
		1421	# this is more than twice as fast as the generic code below
		1422	sub {
		1423	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1424
		1425	$cb->($_[0], $1, $2);
		1426	1
		1427	}
		1428	} else {
672	$eol = quotemeta $eol unless ref $eol;	1429	$eol = quotemeta $eol unless ref $eol;
673	$eol = qr|^(.*?)($eol)|s;	1430	$eol = qr|^(.*?)($eol)|s;
		1431
		1432	sub {
		1433	$_[0]{rbuf} =~ s/$eol// or return;
		1434
		1435	$cb->($_[0], $1, $2);
		1436	1
		1437	}
		1438	}
		1439	};
		1440
		1441	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1442
		1443	Makes a regex match against the regex object C<$accept> and returns
		1444	everything up to and including the match.
		1445
		1446	Example: read a single line terminated by '\n'.
		1447
		1448	$handle->push_read (regex => qr<\n>, sub { ... });
		1449
		1450	If C<$reject> is given and not undef, then it determines when the data is
		1451	to be rejected: it is matched against the data when the C<$accept> regex
		1452	does not match and generates an C<EBADMSG> error when it matches. This is
		1453	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1454	receive buffer overflow).
		1455
		1456	Example: expect a single decimal number followed by whitespace, reject
		1457	anything else (not the use of an anchor).
		1458
		1459	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1460
		1461	If C<$skip> is given and not C<undef>, then it will be matched against
		1462	the receive buffer when neither C<$accept> nor C<$reject> match,
		1463	and everything preceding and including the match will be accepted
		1464	unconditionally. This is useful to skip large amounts of data that you
		1465	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1466	have to start matching from the beginning. This is purely an optimisation
		1467	and is usually worth it only when you expect more than a few kilobytes.
		1468
		1469	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1470	expect the header to be very large (it isn't in practice, but...), we use
		1471	a skip regex to skip initial portions. The skip regex is tricky in that
		1472	it only accepts something not ending in either \015 or \012, as these are
		1473	required for the accept regex.
		1474
		1475	$handle->push_read (regex =>
		1476	qr<\015\012\015\012>,
		1477	undef, # no reject
		1478	qr<^.*[^\015\012]>,
		1479	sub { ... });
		1480
		1481	=cut
		1482
		1483	register_read_type regex => sub {
		1484	my ($self, $cb, $accept, $reject, $skip) = @_;
		1485
		1486	my $data;
		1487	my $rbuf = \$self->{rbuf};
674		1488
675	sub {	1489	sub {
676	$_[0]{rbuf} =~ s/$eol// or return;	1490	# accept
677		1491	if ($$rbuf =~ $accept) {
678	$cb->($_[0], $1, $2);	1492	$data .= substr $$rbuf, 0, $+[0], "";
		1493	$cb->($self, $data);
		1494	return 1;
		1495	}
679	1	1496
		1497	# reject
		1498	if ($reject && $$rbuf =~ $reject) {
		1499	$self->_error (Errno::EBADMSG);
		1500	}
		1501
		1502	# skip
		1503	if ($skip && $$rbuf =~ $skip) {
		1504	$data .= substr $$rbuf, 0, $+[0], "";
		1505	}
		1506
		1507	()
680	}	1508	}
681	};	1509	};
682		1510
683	# compatibility with older API
684	sub push_read_line {
685	my $self = shift;
686	$self->push_read (line => @_);
687	}
688
689	sub unshift_read_line {
690	my $self = shift;
691	$self->unshift_read (line => @_);
692	}
693
694	=item netstring => $cb->($string)	1511	=item netstring => $cb->($handle, $string)
695		1512
696	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).	1513	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
697		1514
698	Throws an error with C<$!> set to EBADMSG on format violations.	1515	Throws an error with C<$!> set to EBADMSG on format violations.
699		1516
…		…
703	my ($self, $cb) = @_;	1520	my ($self, $cb) = @_;
704		1521
705	sub {	1522	sub {
706	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {	1523	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
707	if ($_[0]{rbuf} =~ /[^0-9]/) {	1524	if ($_[0]{rbuf} =~ /[^0-9]/) {
708	$! = &Errno::EBADMSG;	1525	$self->_error (Errno::EBADMSG);
709	$self->error;
710	}	1526	}
711	return;	1527	return;
712	}	1528	}
713		1529
714	my $len = $1;	1530	my $len = $1;
…		…
717	my $string = $_[1];	1533	my $string = $_[1];
718	$_[0]->unshift_read (chunk => 1, sub {	1534	$_[0]->unshift_read (chunk => 1, sub {
719	if ($_[1] eq ",") {	1535	if ($_[1] eq ",") {
720	$cb->($_[0], $string);	1536	$cb->($_[0], $string);
721	} else {	1537	} else {
722	$! = &Errno::EBADMSG;
723	$self->error;	1538	$self->_error (Errno::EBADMSG);
724	}	1539	}
725	});	1540	});
726	});	1541	});
727		1542
728	1	1543	1
729	}	1544	}
730	};	1545	};
731		1546
		1547	=item packstring => $format, $cb->($handle, $string)
		1548
		1549	An octet string prefixed with an encoded length. The encoding C<$format>
		1550	uses the same format as a Perl C<pack> format, but must specify a single
		1551	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1552	optional C<!>, C<< < >> or C<< > >> modifier).
		1553
		1554	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1555	EPP uses a prefix of C<N> (4 octtes).
		1556
		1557	Example: read a block of data prefixed by its length in BER-encoded
		1558	format (very efficient).
		1559
		1560	$handle->push_read (packstring => "w", sub {
		1561	my ($handle, $data) = @_;
		1562	});
		1563
		1564	=cut
		1565
		1566	register_read_type packstring => sub {
		1567	my ($self, $cb, $format) = @_;
		1568
		1569	sub {
		1570	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1571	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1572	or return;
		1573
		1574	$format = length pack $format, $len;
		1575
		1576	# bypass unshift if we already have the remaining chunk
		1577	if ($format + $len <= length $_[0]{rbuf}) {
		1578	my $data = substr $_[0]{rbuf}, $format, $len;
		1579	substr $_[0]{rbuf}, 0, $format + $len, "";
		1580	$cb->($_[0], $data);
		1581	} else {
		1582	# remove prefix
		1583	substr $_[0]{rbuf}, 0, $format, "";
		1584
		1585	# read remaining chunk
		1586	$_[0]->unshift_read (chunk => $len, $cb);
		1587	}
		1588
		1589	1
		1590	}
		1591	};
		1592
		1593	=item json => $cb->($handle, $hash_or_arrayref)
		1594
		1595	Reads a JSON object or array, decodes it and passes it to the
		1596	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1597
		1598	If a C<json> object was passed to the constructor, then that will be used
		1599	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1600
		1601	This read type uses the incremental parser available with JSON version
		1602	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1603	dependency on your own: this module will load the JSON module, but
		1604	AnyEvent does not depend on it itself.
		1605
		1606	Since JSON texts are fully self-delimiting, the C<json> read and write
		1607	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1608	the C<json> write type description, above, for an actual example.
		1609
		1610	=cut
		1611
		1612	register_read_type json => sub {
		1613	my ($self, $cb) = @_;
		1614
		1615	my $json = $self->{json} ||= json_coder;
		1616
		1617	my $data;
		1618	my $rbuf = \$self->{rbuf};
		1619
		1620	sub {
		1621	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1622
		1623	if ($ref) {
		1624	$self->{rbuf} = $json->incr_text;
		1625	$json->incr_text = "";
		1626	$cb->($self, $ref);
		1627
		1628	1
		1629	} elsif ($@) {
		1630	# error case
		1631	$json->incr_skip;
		1632
		1633	$self->{rbuf} = $json->incr_text;
		1634	$json->incr_text = "";
		1635
		1636	$self->_error (Errno::EBADMSG);
		1637
		1638	()
		1639	} else {
		1640	$self->{rbuf} = "";
		1641
		1642	()
		1643	}
		1644	}
		1645	};
		1646
		1647	=item storable => $cb->($handle, $ref)
		1648
		1649	Deserialises a L<Storable> frozen representation as written by the
		1650	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1651	data).
		1652
		1653	Raises C<EBADMSG> error if the data could not be decoded.
		1654
		1655	=cut
		1656
		1657	register_read_type storable => sub {
		1658	my ($self, $cb) = @_;
		1659
		1660	require Storable;
		1661
		1662	sub {
		1663	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1664	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1665	or return;
		1666
		1667	my $format = length pack "w", $len;
		1668
		1669	# bypass unshift if we already have the remaining chunk
		1670	if ($format + $len <= length $_[0]{rbuf}) {
		1671	my $data = substr $_[0]{rbuf}, $format, $len;
		1672	substr $_[0]{rbuf}, 0, $format + $len, "";
		1673	$cb->($_[0], Storable::thaw ($data));
		1674	} else {
		1675	# remove prefix
		1676	substr $_[0]{rbuf}, 0, $format, "";
		1677
		1678	# read remaining chunk
		1679	$_[0]->unshift_read (chunk => $len, sub {
		1680	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1681	$cb->($_[0], $ref);
		1682	} else {
		1683	$self->_error (Errno::EBADMSG);
		1684	}
		1685	});
		1686	}
		1687
		1688	1
		1689	}
		1690	};
		1691
732	=back	1692	=back
733		1693
734	=item AnyEvent::Handle::register_read_type type => $coderef->($self, $cb, @args)	1694	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
735		1695
736	This function (not method) lets you add your own types to C<push_read>.	1696	Instead of one of the predefined types, you can also specify the name
		1697	of a package. AnyEvent will try to load the package and then expects to
		1698	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1699	progressively tries to load the parent package until it either finds the
		1700	function (good) or runs out of packages (bad).
737		1701
738	Whenever the given C<type> is used, C<push_read> will invoke the code	1702	Whenever this type is used, C<push_read> will invoke the function with the
739	reference with the handle object, the callback and the remaining	1703	handle object, the original callback and the remaining arguments.
740	arguments.
741		1704
742	The code reference is supposed to return a callback (usually a closure)	1705	The function is supposed to return a callback (usually a closure) that
743	that works as a plain read callback (see C<< ->push_read ($cb) >>).	1706	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1707	mentally treat the function as a "configurable read type to read callback"
		1708	converter.
744		1709
745	It should invoke the passed callback when it is done reading (remember to	1710	It should invoke the original callback when it is done reading (remember
746	pass C<$self> as first argument as all other callbacks do that).	1711	to pass C<$handle> as first argument as all other callbacks do that,
		1712	although there is no strict requirement on this).
747		1713
748	Note that this is a function, and all types registered this way will be
749	global, so try to use unique names.
750
751	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,	1714	For examples, see the source of this module (F<perldoc -m
752	search for C<register_read_type>)).	1715	AnyEvent::Handle>, search for C<register_read_type>)).
753		1716
754	=item $handle->stop_read	1717	=item $handle->stop_read
755		1718
756	=item $handle->start_read	1719	=item $handle->start_read
757		1720
758	In rare cases you actually do not want to read anything from the	1721	In rare cases you actually do not want to read anything from the
759	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1722	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
760	any queued callbacks will be executed then. To start reading again, call	1723	any queued callbacks will be executed then. To start reading again, call
761	C<start_read>.	1724	C<start_read>.
762		1725
		1726	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1727	you change the C<on_read> callback or push/unshift a read callback, and it
		1728	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1729	there are any read requests in the queue.
		1730
		1731	These methods will have no effect when in TLS mode (as TLS doesn't support
		1732	half-duplex connections).
		1733
763	=cut	1734	=cut
764		1735
765	sub stop_read {	1736	sub stop_read {
766	my ($self) = @_;	1737	my ($self) = @_;
767		1738
768	delete $self->{rw};	1739	delete $self->{_rw} unless $self->{tls};
769	}	1740	}
770		1741
771	sub start_read {	1742	sub start_read {
772	my ($self) = @_;	1743	my ($self) = @_;
773		1744
774	unless ($self->{rw} || $self->{eof}) {	1745	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
775	Scalar::Util::weaken $self;	1746	Scalar::Util::weaken $self;
776		1747
777	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1748	$self->{_rw} = AE::io $self->{fh}, 0, sub {
778	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1749	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
779	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1750	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
780		1751
781	if ($len > 0) {	1752	if ($len > 0) {
782	$self->{filter_r}	1753	$self->{_activity} = $self->{_ractivity} = AE::now;
783	? $self->{filter_r}->($self, $rbuf)	1754
		1755	if ($self->{tls}) {
		1756	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1757
		1758	&_dotls ($self);
		1759	} else {
784	: $self->_drain_rbuf;	1760	$self->_drain_rbuf;
		1761	}
785		1762
786	} elsif (defined $len) {	1763	} elsif (defined $len) {
787	delete $self->{rw};	1764	delete $self->{_rw};
788	$self->{eof} = 1;	1765	$self->{_eof} = 1;
789	$self->_drain_rbuf;	1766	$self->_drain_rbuf;
790		1767
791	} elsif ($! != EAGAIN && $! != EINTR) {	1768	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
792	return $self->error;	1769	return $self->_error ($!, 1);
793	}	1770	}
794	});	1771	};
795	}	1772	}
796	}	1773	}
797		1774
		1775	our $ERROR_SYSCALL;
		1776	our $ERROR_WANT_READ;
		1777
		1778	sub _tls_error {
		1779	my ($self, $err) = @_;
		1780
		1781	return $self->_error ($!, 1)
		1782	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1783
		1784	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1785
		1786	# reduce error string to look less scary
		1787	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1788
		1789	if ($self->{_on_starttls}) {
		1790	(delete $self->{_on_starttls})->($self, undef, $err);
		1791	&_freetls;
		1792	} else {
		1793	&_freetls;
		1794	$self->_error (Errno::EPROTO, 1, $err);
		1795	}
		1796	}
		1797
		1798	# poll the write BIO and send the data if applicable
		1799	# also decode read data if possible
		1800	# this is basiclaly our TLS state machine
		1801	# more efficient implementations are possible with openssl,
		1802	# but not with the buggy and incomplete Net::SSLeay.
798	sub _dotls {	1803	sub _dotls {
799	my ($self) = @_;	1804	my ($self) = @_;
800		1805
		1806	my $tmp;
		1807
801	if (length $self->{tls_wbuf}) {	1808	if (length $self->{_tls_wbuf}) {
802	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{tls_wbuf})) > 0) {	1809	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
803	substr $self->{tls_wbuf}, 0, $len, "";	1810	substr $self->{_tls_wbuf}, 0, $tmp, "";
804	}	1811	}
805	}
806		1812
		1813	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1814	return $self->_tls_error ($tmp)
		1815	if $tmp != $ERROR_WANT_READ
		1816	&& ($tmp != $ERROR_SYSCALL || $!);
		1817	}
		1818
807	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{tls_wbio}))) {	1819	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1820	unless (length $tmp) {
		1821	$self->{_on_starttls}
		1822	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1823	&_freetls;
		1824
		1825	if ($self->{on_stoptls}) {
		1826	$self->{on_stoptls}($self);
		1827	return;
		1828	} else {
		1829	# let's treat SSL-eof as we treat normal EOF
		1830	delete $self->{_rw};
		1831	$self->{_eof} = 1;
		1832	}
		1833	}
		1834
		1835	$self->{_tls_rbuf} .= $tmp;
		1836	$self->_drain_rbuf;
		1837	$self->{tls} or return; # tls session might have gone away in callback
		1838	}
		1839
		1840	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1841	return $self->_tls_error ($tmp)
		1842	if $tmp != $ERROR_WANT_READ
		1843	&& ($tmp != $ERROR_SYSCALL || $!);
		1844
		1845	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
808	$self->{wbuf} .= $buf;	1846	$self->{wbuf} .= $tmp;
809	$self->_drain_wbuf;	1847	$self->_drain_wbuf;
		1848	$self->{tls} or return; # tls session might have gone away in callback
810	}	1849	}
811		1850
812	while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {	1851	$self->{_on_starttls}
813	$self->{rbuf} .= $buf;	1852	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
814	$self->_drain_rbuf;	1853	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
815	}
816
817	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
818
819	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
820	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
821	$self->error;
822	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
823	$! = &Errno::EIO;
824	$self->error;
825	}
826
827	# all others are fine for our purposes
828	}
829	}	1854	}
830		1855
831	=item $handle->starttls ($tls[, $tls_ctx])	1856	=item $handle->starttls ($tls[, $tls_ctx])
832		1857
833	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1858	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
834	object is created, you can also do that at a later time by calling	1859	object is created, you can also do that at a later time by calling
835	C<starttls>.	1860	C<starttls>.
836		1861
		1862	Starting TLS is currently an asynchronous operation - when you push some
		1863	write data and then call C<< ->starttls >> then TLS negotiation will start
		1864	immediately, after which the queued write data is then sent.
		1865
837	The first argument is the same as the C<tls> constructor argument (either	1866	The first argument is the same as the C<tls> constructor argument (either
838	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1867	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
839		1868
840	The second argument is the optional C<Net::SSLeay::CTX> object that is	1869	The second argument is the optional C<AnyEvent::TLS> object that is used
841	used when AnyEvent::Handle has to create its own TLS connection object.	1870	when AnyEvent::Handle has to create its own TLS connection object, or
		1871	a hash reference with C<< key => value >> pairs that will be used to
		1872	construct a new context.
842		1873
843	=cut	1874	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1875	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1876	changed to your liking. Note that the handshake might have already started
		1877	when this function returns.
844		1878
845	# TODO: maybe document...	1879	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1880	handshakes on the same stream. It is best to not attempt to use the
		1881	stream after stopping TLS.
		1882
		1883	This method may invoke callbacks (and therefore the handle might be
		1884	destroyed after it returns).
		1885
		1886	=cut
		1887
		1888	our %TLS_CACHE; #TODO not yet documented, should we?
		1889
846	sub starttls {	1890	sub starttls {
847	my ($self, $ssl, $ctx) = @_;	1891	my ($self, $tls, $ctx) = @_;
848		1892
849	$self->stoptls;	1893	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1894	if $self->{tls};
850		1895
851	if ($ssl eq "accept") {	1896	$self->{tls} = $tls;
852	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1897	$self->{tls_ctx} = $ctx if @_ > 2;
853	Net::SSLeay::set_accept_state ($ssl);	1898
854	} elsif ($ssl eq "connect") {	1899	return unless $self->{fh};
855	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1900
856	Net::SSLeay::set_connect_state ($ssl);	1901	require Net::SSLeay;
		1902
		1903	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1904	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1905
		1906	$tls = delete $self->{tls};
		1907	$ctx = $self->{tls_ctx};
		1908
		1909	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1910
		1911	if ("HASH" eq ref $ctx) {
		1912	require AnyEvent::TLS;
		1913
		1914	if ($ctx->{cache}) {
		1915	my $key = $ctx+0;
		1916	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1917	} else {
		1918	$ctx = new AnyEvent::TLS %$ctx;
		1919	}
		1920	}
857	}	1921
858		1922	$self->{tls_ctx} = $ctx || TLS_CTX ();
859	$self->{tls} = $ssl;	1923	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
860		1924
861	# basically, this is deep magic (because SSL_read should have the same issues)	1925	# basically, this is deep magic (because SSL_read should have the same issues)
862	# but the openssl maintainers basically said: "trust us, it just works".	1926	# but the openssl maintainers basically said: "trust us, it just works".
863	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1927	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
864	# and mismaintained ssleay-module doesn't even offer them).	1928	# and mismaintained ssleay-module doesn't even offer them).
865	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1929	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1930	#
		1931	# in short: this is a mess.
		1932	#
		1933	# note that we do not try to keep the length constant between writes as we are required to do.
		1934	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1935	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1936	# have identity issues in that area.
866	Net::SSLeay::CTX_set_mode ($self->{tls},	1937	# Net::SSLeay::CTX_set_mode ($ssl,
867	(eval { Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	1938	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
868	| (eval { Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	1939	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1940	Net::SSLeay::CTX_set_mode ($tls, 1|2);
869		1941
870	$self->{tls_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1942	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
871	$self->{tls_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1943	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
872		1944
		1945	Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf});
		1946
873	Net::SSLeay::set_bio ($ssl, $self->{tls_rbio}, $self->{tls_wbio});	1947	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
874		1948
875	$self->{filter_w} = sub {	1949	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
876	$_[0]{tls_wbuf} .= ${$_[1]};	1950	if $self->{on_starttls};
877	&_dotls;	1951
878	};	1952	&_dotls; # need to trigger the initial handshake
879	$self->{filter_r} = sub {	1953	$self->start_read; # make sure we actually do read
880	Net::SSLeay::BIO_write ($_[0]{tls_rbio}, ${$_[1]});
881	&_dotls;
882	};
883	}	1954	}
884		1955
885	=item $handle->stoptls	1956	=item $handle->stoptls
886		1957
887	Destroys the SSL connection, if any. Partial read or write data will be	1958	Shuts down the SSL connection - this makes a proper EOF handshake by
888	lost.	1959	sending a close notify to the other side, but since OpenSSL doesn't
		1960	support non-blocking shut downs, it is not guaranteed that you can re-use
		1961	the stream afterwards.
		1962
		1963	This method may invoke callbacks (and therefore the handle might be
		1964	destroyed after it returns).
889		1965
890	=cut	1966	=cut
891		1967
892	sub stoptls {	1968	sub stoptls {
893	my ($self) = @_;	1969	my ($self) = @_;
894		1970
895	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	1971	if ($self->{tls} && $self->{fh}) {
896	delete $self->{tls_rbio};	1972	Net::SSLeay::shutdown ($self->{tls});
897	delete $self->{tls_wbio};	1973
898	delete $self->{tls_wbuf};	1974	&_dotls;
899	delete $self->{filter_r};	1975
900	delete $self->{filter_w};	1976	# # we don't give a shit. no, we do, but we can't. no...#d#
		1977	# # we, we... have to use openssl :/#d#
		1978	# &_freetls;#d#
		1979	}
		1980	}
		1981
		1982	sub _freetls {
		1983	my ($self) = @_;
		1984
		1985	return unless $self->{tls};
		1986
		1987	$self->{tls_ctx}->_put_session (delete $self->{tls})
		1988	if $self->{tls} > 0;
		1989
		1990	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
901	}	1991	}
902		1992
903	sub DESTROY {	1993	sub DESTROY {
904	my $self = shift;	1994	my ($self) = @_;
905		1995
906	$self->stoptls;	1996	&_freetls;
		1997
		1998	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1999
		2000	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2001	my $fh = delete $self->{fh};
		2002	my $wbuf = delete $self->{wbuf};
		2003
		2004	my @linger;
		2005
		2006	push @linger, AE::io $fh, 1, sub {
		2007	my $len = syswrite $fh, $wbuf, length $wbuf;
		2008
		2009	if ($len > 0) {
		2010	substr $wbuf, 0, $len, "";
		2011	} else {
		2012	@linger = (); # end
		2013	}
		2014	};
		2015	push @linger, AE::timer $linger, 0, sub {
		2016	@linger = ();
		2017	};
		2018	}
907	}	2019	}
		2020
		2021	=item $handle->destroy
		2022
		2023	Shuts down the handle object as much as possible - this call ensures that
		2024	no further callbacks will be invoked and as many resources as possible
		2025	will be freed. Any method you will call on the handle object after
		2026	destroying it in this way will be silently ignored (and it will return the
		2027	empty list).
		2028
		2029	Normally, you can just "forget" any references to an AnyEvent::Handle
		2030	object and it will simply shut down. This works in fatal error and EOF
		2031	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2032	callback, so when you want to destroy the AnyEvent::Handle object from
		2033	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2034	that case.
		2035
		2036	Destroying the handle object in this way has the advantage that callbacks
		2037	will be removed as well, so if those are the only reference holders (as
		2038	is common), then one doesn't need to do anything special to break any
		2039	reference cycles.
		2040
		2041	The handle might still linger in the background and write out remaining
		2042	data, as specified by the C<linger> option, however.
		2043
		2044	=cut
		2045
		2046	sub destroy {
		2047	my ($self) = @_;
		2048
		2049	$self->DESTROY;
		2050	%$self = ();
		2051	bless $self, "AnyEvent::Handle::destroyed";
		2052	}
		2053
		2054	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2055	#nop
		2056	}
		2057
		2058	=item $handle->destroyed
		2059
		2060	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2061	->destroy >>, true otherwise.
		2062
		2063	Can be useful to decide whether the handle is still valid after some
		2064	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2065	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2066	can destroy the handle, so work can be avoided by checking sometimes:
		2067
		2068	$hdl->starttls ("accept");
		2069	return if $hdl->destroyed;
		2070	$hdl->push_write (...
		2071
		2072	Note that the call to C<push_write> will silently be ignored if the handle
		2073	has been destroyed, so often you can just ignore the possibility of the
		2074	handle being destroyed.
		2075
		2076	=cut
		2077
		2078	sub destroyed { 0 }
		2079	sub AnyEvent::Handle::destroyed::destroyed { 1 }
908		2080
909	=item AnyEvent::Handle::TLS_CTX	2081	=item AnyEvent::Handle::TLS_CTX
910		2082
911	This function creates and returns the Net::SSLeay::CTX object used by	2083	This function creates and returns the AnyEvent::TLS object used by default
912	default for TLS mode.	2084	for TLS mode.
913		2085
914	The context is created like this:	2086	The context is created by calling L<AnyEvent::TLS> without any arguments.
915
916	Net::SSLeay::load_error_strings;
917	Net::SSLeay::SSLeay_add_ssl_algorithms;
918	Net::SSLeay::randomize;
919
920	my $CTX = Net::SSLeay::CTX_new;
921
922	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
923		2087
924	=cut	2088	=cut
925		2089
926	our $TLS_CTX;	2090	our $TLS_CTX;
927		2091
928	sub TLS_CTX() {	2092	sub TLS_CTX() {
929	$TLS_CTX || do {	2093	$TLS_CTX ||= do {
930	require Net::SSLeay;	2094	require AnyEvent::TLS;
931		2095
932	Net::SSLeay::load_error_strings ();	2096	new AnyEvent::TLS
933	Net::SSLeay::SSLeay_add_ssl_algorithms ();
934	Net::SSLeay::randomize ();
935
936	$TLS_CTX = Net::SSLeay::CTX_new ();
937
938	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
939
940	$TLS_CTX
941	}	2097	}
942	}	2098	}
943		2099
944	=back	2100	=back
945		2101
		2102
		2103	=head1 NONFREQUENTLY ASKED QUESTIONS
		2104
		2105	=over 4
		2106
		2107	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2108	still get further invocations!
		2109
		2110	That's because AnyEvent::Handle keeps a reference to itself when handling
		2111	read or write callbacks.
		2112
		2113	It is only safe to "forget" the reference inside EOF or error callbacks,
		2114	from within all other callbacks, you need to explicitly call the C<<
		2115	->destroy >> method.
		2116
		2117	=item I get different callback invocations in TLS mode/Why can't I pause
		2118	reading?
		2119
		2120	Unlike, say, TCP, TLS connections do not consist of two independent
		2121	communication channels, one for each direction. Or put differently, the
		2122	read and write directions are not independent of each other: you cannot
		2123	write data unless you are also prepared to read, and vice versa.
		2124
		2125	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2126	callback invocations when you are not expecting any read data - the reason
		2127	is that AnyEvent::Handle always reads in TLS mode.
		2128
		2129	During the connection, you have to make sure that you always have a
		2130	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2131	connection (or when you no longer want to use it) you can call the
		2132	C<destroy> method.
		2133
		2134	=item How do I read data until the other side closes the connection?
		2135
		2136	If you just want to read your data into a perl scalar, the easiest way
		2137	to achieve this is by setting an C<on_read> callback that does nothing,
		2138	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2139	will be in C<$_[0]{rbuf}>:
		2140
		2141	$handle->on_read (sub { });
		2142	$handle->on_eof (undef);
		2143	$handle->on_error (sub {
		2144	my $data = delete $_[0]{rbuf};
		2145	});
		2146
		2147	The reason to use C<on_error> is that TCP connections, due to latencies
		2148	and packets loss, might get closed quite violently with an error, when in
		2149	fact all data has been received.
		2150
		2151	It is usually better to use acknowledgements when transferring data,
		2152	to make sure the other side hasn't just died and you got the data
		2153	intact. This is also one reason why so many internet protocols have an
		2154	explicit QUIT command.
		2155
		2156	=item I don't want to destroy the handle too early - how do I wait until
		2157	all data has been written?
		2158
		2159	After writing your last bits of data, set the C<on_drain> callback
		2160	and destroy the handle in there - with the default setting of
		2161	C<low_water_mark> this will be called precisely when all data has been
		2162	written to the socket:
		2163
		2164	$handle->push_write (...);
		2165	$handle->on_drain (sub {
		2166	warn "all data submitted to the kernel\n";
		2167	undef $handle;
		2168	});
		2169
		2170	If you just want to queue some data and then signal EOF to the other side,
		2171	consider using C<< ->push_shutdown >> instead.
		2172
		2173	=item I want to contact a TLS/SSL server, I don't care about security.
		2174
		2175	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2176	connect to it and then create the AnyEvent::Handle with the C<tls>
		2177	parameter:
		2178
		2179	tcp_connect $host, $port, sub {
		2180	my ($fh) = @_;
		2181
		2182	my $handle = new AnyEvent::Handle
		2183	fh => $fh,
		2184	tls => "connect",
		2185	on_error => sub { ... };
		2186
		2187	$handle->push_write (...);
		2188	};
		2189
		2190	=item I want to contact a TLS/SSL server, I do care about security.
		2191
		2192	Then you should additionally enable certificate verification, including
		2193	peername verification, if the protocol you use supports it (see
		2194	L<AnyEvent::TLS>, C<verify_peername>).
		2195
		2196	E.g. for HTTPS:
		2197
		2198	tcp_connect $host, $port, sub {
		2199	my ($fh) = @_;
		2200
		2201	my $handle = new AnyEvent::Handle
		2202	fh => $fh,
		2203	peername => $host,
		2204	tls => "connect",
		2205	tls_ctx => { verify => 1, verify_peername => "https" },
		2206	...
		2207
		2208	Note that you must specify the hostname you connected to (or whatever
		2209	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2210	peername verification will be done.
		2211
		2212	The above will use the system-dependent default set of trusted CA
		2213	certificates. If you want to check against a specific CA, add the
		2214	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2215
		2216	tls_ctx => {
		2217	verify => 1,
		2218	verify_peername => "https",
		2219	ca_file => "my-ca-cert.pem",
		2220	},
		2221
		2222	=item I want to create a TLS/SSL server, how do I do that?
		2223
		2224	Well, you first need to get a server certificate and key. You have
		2225	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2226	self-signed certificate (cheap. check the search engine of your choice,
		2227	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2228	nice program for that purpose).
		2229
		2230	Then create a file with your private key (in PEM format, see
		2231	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2232	file should then look like this:
		2233
		2234	-----BEGIN RSA PRIVATE KEY-----
		2235	...header data
		2236	... lots of base64'y-stuff
		2237	-----END RSA PRIVATE KEY-----
		2238
		2239	-----BEGIN CERTIFICATE-----
		2240	... lots of base64'y-stuff
		2241	-----END CERTIFICATE-----
		2242
		2243	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2244	specify this file as C<cert_file>:
		2245
		2246	tcp_server undef, $port, sub {
		2247	my ($fh) = @_;
		2248
		2249	my $handle = new AnyEvent::Handle
		2250	fh => $fh,
		2251	tls => "accept",
		2252	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2253	...
		2254
		2255	When you have intermediate CA certificates that your clients might not
		2256	know about, just append them to the C<cert_file>.
		2257
		2258	=back
		2259
		2260
		2261	=head1 SUBCLASSING AnyEvent::Handle
		2262
		2263	In many cases, you might want to subclass AnyEvent::Handle.
		2264
		2265	To make this easier, a given version of AnyEvent::Handle uses these
		2266	conventions:
		2267
		2268	=over 4
		2269
		2270	=item * all constructor arguments become object members.
		2271
		2272	At least initially, when you pass a C<tls>-argument to the constructor it
		2273	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2274	mutated later on (for example C<tls> will hold the TLS connection object).
		2275
		2276	=item * other object member names are prefixed with an C<_>.
		2277
		2278	All object members not explicitly documented (internal use) are prefixed
		2279	with an underscore character, so the remaining non-C<_>-namespace is free
		2280	for use for subclasses.
		2281
		2282	=item * all members not documented here and not prefixed with an underscore
		2283	are free to use in subclasses.
		2284
		2285	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2286	member variables, but that's just life. At least it is documented.
		2287
		2288	=back
		2289
946	=head1 AUTHOR	2290	=head1 AUTHOR
947		2291
948	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	2292	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
949		2293
950	=cut	2294	=cut

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