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Revision 1.12 by elmex, Thu May 15 09:03:43 2008 UTC vs.
Revision 1.234 by root, Wed Apr 18 09:44:10 2012 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 filehandles via AnyEvent	3	AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
16
17	=cut
18
19	our $VERSION = '0.02';
20		4
21	=head1 SYNOPSIS	5	=head1 SYNOPSIS
22		6
23	use AnyEvent;	7	use AnyEvent;
24	use AnyEvent::Handle;	8	use AnyEvent::Handle;
25		9
26	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
27		11
28	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	12	my $hdl; $hdl = new AnyEvent::Handle
29
30	#TODO
31
32	# or use the constructor to pass the callback:
33
34	my $ae_fh2 =
35	AnyEvent::Handle->new (
36	fh => \*STDIN,	13	fh => \*STDIN,
37	on_eof => sub {	14	on_error => sub {
38	$cv->broadcast;	15	my ($hdl, $fatal, $msg) = @_;
39	},	16	AE::log error => $msg;
40	#TODO	17	$hdl->destroy;
		18	$cv->send;
41	);	19	};
42		20
43	$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, $line) = @_;
		27	say "got line <$line>";
		28	$cv->send;
		29	});
		30
		31	$cv->recv;
44		32
45	=head1 DESCRIPTION	33	=head1 DESCRIPTION
46		34
47	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
48	filehandles (and sockets, see L<AnyEvent::Socket> for an easy way to make	36	stream-based filehandles (sockets, pipes, and other stream things).
49	non-blocking resolves and connects).
50		37
		38	The L<AnyEvent::Intro> tutorial contains some well-documented
		39	AnyEvent::Handle examples.
		40
51	In the following, when the documentation refers to of "bytes" then this	41	In the following, where the documentation refers to "bytes", it means
52	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
53	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.
54		47
55	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
56	argument.	49	argument.
57		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
		80	sub MAX_READ_SIZE() { 131072 }
		81
58	=head1 METHODS	82	=head1 METHODS
59		83
60	=over 4	84	=over 4
61		85
62	=item B<new (%args)>	86	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
63		87
64	The constructor supports these arguments (all as key => value pairs).	88	The constructor supports these arguments (all as C<< key => value >> pairs).
65		89
66	=over 4	90	=over 4
67		91
68	=item fh => $filehandle [MANDATORY]	92	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
69		93
70	The filehandle this L<AnyEvent::Handle> object will operate on.	94	The filehandle this L<AnyEvent::Handle> object will operate on.
71
72	NOTE: The filehandle will be set to non-blocking (using	95	NOTE: The filehandle will be set to non-blocking mode (using
73	AnyEvent::Util::fh_nonblocking).	96	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		97	that mode.
74		98
75	=item on_eof => $cb->($self) [MANDATORY]	99	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
76		100
77	Set the callback to be called on EOF.	101	Try to connect to the specified host and service (port), using
		102	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		103	default C<peername>.
78		104
		105	You have to specify either this parameter, or C<fh>, above.
		106
		107	It is possible to push requests on the read and write queues, and modify
		108	properties of the stream, even while AnyEvent::Handle is connecting.
		109
		110	When this parameter is specified, then the C<on_prepare>,
		111	C<on_connect_error> and C<on_connect> callbacks will be called under the
		112	appropriate circumstances:
		113
		114	=over 4
		115
79	=item on_error => $cb->($self)	116	=item on_prepare => $cb->($handle)
80		117
		118	This (rarely used) callback is called before a new connection is
		119	attempted, but after the file handle has been created (you can access that
		120	file handle via C<< $handle->{fh} >>). It could be used to prepare the
		121	file handle with parameters required for the actual connect (as opposed to
		122	settings that can be changed when the connection is already established).
		123
		124	The return value of this callback should be the connect timeout value in
		125	seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
		126	default timeout is to be used).
		127
		128	=item on_connect => $cb->($handle, $host, $port, $retry->())
		129
		130	This callback is called when a connection has been successfully established.
		131
		132	The peer's numeric host and port (the socket peername) are passed as
		133	parameters, together with a retry callback. At the time it is called the
		134	read and write queues, EOF status, TLS status and similar properties of
		135	the handle will have been reset.
		136
		137	It is not allowed to use the read or write queues while the handle object
		138	is connecting.
		139
		140	If, for some reason, the handle is not acceptable, calling C<$retry> will
		141	continue with the next connection target (in case of multi-homed hosts or
		142	SRV records there can be multiple connection endpoints). The C<$retry>
		143	callback can be invoked after the connect callback returns, i.e. one can
		144	start a handshake and then decide to retry with the next host if the
		145	handshake fails.
		146
		147	In most cases, you should ignore the C<$retry> parameter.
		148
		149	=item on_connect_error => $cb->($handle, $message)
		150
		151	This callback is called when the connection could not be
		152	established. C<$!> will contain the relevant error code, and C<$message> a
		153	message describing it (usually the same as C<"$!">).
		154
		155	If this callback isn't specified, then C<on_error> will be called with a
		156	fatal error instead.
		157
		158	=back
		159
		160	=item on_error => $cb->($handle, $fatal, $message)
		161
81	This is the fatal error callback, that is called when, well, a fatal error	162	This is the error callback, which is called when, well, some error
82	ocurs, such as not being able to resolve the hostname, failure to connect	163	occured, such as not being able to resolve the hostname, failure to
83	or a read error.	164	connect, or a read error.
84		165
85	The object will not be in a usable state when this callback has been	166	Some errors are fatal (which is indicated by C<$fatal> being true). On
86	called.	167	fatal errors the handle object will be destroyed (by a call to C<< ->
		168	destroy >>) after invoking the error callback (which means you are free to
		169	examine the handle object). Examples of fatal errors are an EOF condition
		170	with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
		171	cases where the other side can close the connection at will, it is
		172	often easiest to not report C<EPIPE> errors in this callback.
87		173
		174	AnyEvent::Handle tries to find an appropriate error code for you to check
		175	against, but in some cases (TLS errors), this does not work well.
		176
		177	If you report the error to the user, it is recommended to always output
		178	the C<$message> argument in human-readable error messages (you don't need
		179	to report C<"$!"> if you report C<$message>).
		180
		181	If you want to react programmatically to the error, then looking at C<$!>
		182	and comparing it against some of the documented C<Errno> values is usually
		183	better than looking at the C<$message>.
		184
		185	Non-fatal errors can be retried by returning, but it is recommended
		186	to simply ignore this parameter and instead abondon the handle object
		187	when this callback is invoked. Examples of non-fatal errors are timeouts
		188	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		189
88	On callback entrance, the value of C<$!> contains the operating system	190	On entry to the callback, the value of C<$!> contains the operating
89	error (or C<ENOSPC> or C<EPIPE>).	191	system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		192	C<EPROTO>).
90		193
91	While not mandatory, it is I<highly> recommended to set this callback, as	194	While not mandatory, it is I<highly> recommended to set this callback, as
92	you will not be notified of errors otherwise. The default simply calls	195	you will not be notified of errors otherwise. The default just calls
93	die.	196	C<croak>.
94		197
95	=item on_read => $cb->($self)	198	=item on_read => $cb->($handle)
96		199
97	This sets the default read callback, which is called when data arrives	200	This sets the default read callback, which is called when data arrives
98	and no read request is in the queue.	201	and no read request is in the queue (unlike read queue callbacks, this
		202	callback will only be called when at least one octet of data is in the
		203	read buffer).
99		204
100	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	205	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
101	method or acces sthe C<$self->{rbuf}> member directly.	206	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		207	must not enlarge or modify the read buffer, you can only remove data at
		208	the beginning from it.
102		209
		210	You can also call C<< ->push_read (...) >> or any other function that
		211	modifies the read queue. Or do both. Or ...
		212
103	When an EOF condition is detected then AnyEvent::Handle will first try to	213	When an EOF condition is detected, AnyEvent::Handle will first try to
104	feed all the remaining data to the queued callbacks and C<on_read> before	214	feed all the remaining data to the queued callbacks and C<on_read> before
105	calling the C<on_eof> callback. If no progress can be made, then a fatal	215	calling the C<on_eof> callback. If no progress can be made, then a fatal
106	error will be raised (with C<$!> set to C<EPIPE>).	216	error will be raised (with C<$!> set to C<EPIPE>).
107		217
		218	Note that, unlike requests in the read queue, an C<on_read> callback
		219	doesn't mean you I<require> some data: if there is an EOF and there
		220	are outstanding read requests then an error will be flagged. With an
		221	C<on_read> callback, the C<on_eof> callback will be invoked.
		222
		223	=item on_eof => $cb->($handle)
		224
		225	Set the callback to be called when an end-of-file condition is detected,
		226	i.e. in the case of a socket, when the other side has closed the
		227	connection cleanly, and there are no outstanding read requests in the
		228	queue (if there are read requests, then an EOF counts as an unexpected
		229	connection close and will be flagged as an error).
		230
		231	For sockets, this just means that the other side has stopped sending data,
		232	you can still try to write data, and, in fact, one can return from the EOF
		233	callback and continue writing data, as only the read part has been shut
		234	down.
		235
		236	If an EOF condition has been detected but no C<on_eof> callback has been
		237	set, then a fatal error will be raised with C<$!> set to <0>.
		238
108	=item on_drain => $cb->()	239	=item on_drain => $cb->($handle)
109		240
110	This sets the callback that is called when the write buffer becomes empty	241	This sets the callback that is called once when the write buffer becomes
111	(or when the callback is set and the buffer is empty already).	242	empty (and immediately when the handle object is created).
112		243
113	To append to the write buffer, use the C<< ->push_write >> method.	244	To append to the write buffer, use the C<< ->push_write >> method.
		245
		246	This callback is useful when you don't want to put all of your write data
		247	into the queue at once, for example, when you want to write the contents
		248	of some file to the socket you might not want to read the whole file into
		249	memory and push it into the queue, but instead only read more data from
		250	the file when the write queue becomes empty.
		251
		252	=item timeout => $fractional_seconds
		253
		254	=item rtimeout => $fractional_seconds
		255
		256	=item wtimeout => $fractional_seconds
		257
		258	If non-zero, then these enables an "inactivity" timeout: whenever this
		259	many seconds pass without a successful read or write on the underlying
		260	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
		261	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		262	error will be raised).
		263
		264	There are three variants of the timeouts that work independently of each
		265	other, for both read and write (triggered when nothing was read I<OR>
		266	written), just read (triggered when nothing was read), and just write:
		267	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		268	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		269	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		270
		271	Note that timeout processing is active even when you do not have any
		272	outstanding read or write requests: If you plan to keep the connection
		273	idle then you should disable the timeout temporarily or ignore the
		274	timeout in the corresponding C<on_timeout> callback, in which case
		275	AnyEvent::Handle will simply restart the timeout.
		276
		277	Zero (the default) disables the corresponding timeout.
		278
		279	=item on_timeout => $cb->($handle)
		280
		281	=item on_rtimeout => $cb->($handle)
		282
		283	=item on_wtimeout => $cb->($handle)
		284
		285	Called whenever the inactivity timeout passes. If you return from this
		286	callback, then the timeout will be reset as if some activity had happened,
		287	so this condition is not fatal in any way.
114		288
115	=item rbuf_max => <bytes>	289	=item rbuf_max => <bytes>
116		290
117	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	291	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
118	when the read buffer ever (strictly) exceeds this size. This is useful to	292	when the read buffer ever (strictly) exceeds this size. This is useful to
119	avoid denial-of-service attacks.	293	avoid some forms of denial-of-service attacks.
120		294
121	For example, a server accepting connections from untrusted sources should	295	For example, a server accepting connections from untrusted sources should
122	be configured to accept only so-and-so much data that it cannot act on	296	be configured to accept only so-and-so much data that it cannot act on
123	(for example, when expecting a line, an attacker could send an unlimited	297	(for example, when expecting a line, an attacker could send an unlimited
124	amount of data without a callback ever being called as long as the line	298	amount of data without a callback ever being called as long as the line
125	isn't finished).	299	isn't finished).
126		300
		301	=item wbuf_max => <bytes>
		302
		303	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		304	when the write buffer ever (strictly) exceeds this size. This is useful to
		305	avoid some forms of denial-of-service attacks.
		306
		307	Although the units of this parameter is bytes, this is the I<raw> number
		308	of bytes not yet accepted by the kernel. This can make a difference when
		309	you e.g. use TLS, as TLS typically makes your write data larger (but it
		310	can also make it smaller due to compression).
		311
		312	As an example of when this limit is useful, take a chat server that sends
		313	chat messages to a client. If the client does not read those in a timely
		314	manner then the send buffer in the server would grow unbounded.
		315
		316	=item autocork => <boolean>
		317
		318	When disabled (the default), C<push_write> will try to immediately
		319	write the data to the handle if possible. This avoids having to register
		320	a write watcher and wait for the next event loop iteration, but can
		321	be inefficient if you write multiple small chunks (on the wire, this
		322	disadvantage is usually avoided by your kernel's nagle algorithm, see
		323	C<no_delay>, but this option can save costly syscalls).
		324
		325	When enabled, writes will always be queued till the next event loop
		326	iteration. This is efficient when you do many small writes per iteration,
		327	but less efficient when you do a single write only per iteration (or when
		328	the write buffer often is full). It also increases write latency.
		329
		330	=item no_delay => <boolean>
		331
		332	When doing small writes on sockets, your operating system kernel might
		333	wait a bit for more data before actually sending it out. This is called
		334	the Nagle algorithm, and usually it is beneficial.
		335
		336	In some situations you want as low a delay as possible, which can be
		337	accomplishd by setting this option to a true value.
		338
		339	The default is your operating system's default behaviour (most likely
		340	enabled). This option explicitly enables or disables it, if possible.
		341
		342	=item keepalive => <boolean>
		343
		344	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		345	normally, TCP connections have no time-out once established, so TCP
		346	connections, once established, can stay alive forever even when the other
		347	side has long gone. TCP keepalives are a cheap way to take down long-lived
		348	TCP connections when the other side becomes unreachable. While the default
		349	is OS-dependent, TCP keepalives usually kick in after around two hours,
		350	and, if the other side doesn't reply, take down the TCP connection some 10
		351	to 15 minutes later.
		352
		353	It is harmless to specify this option for file handles that do not support
		354	keepalives, and enabling it on connections that are potentially long-lived
		355	is usually a good idea.
		356
		357	=item oobinline => <boolean>
		358
		359	BSD majorly fucked up the implementation of TCP urgent data. The result
		360	is that almost no OS implements TCP according to the specs, and every OS
		361	implements it slightly differently.
		362
		363	If you want to handle TCP urgent data, then setting this flag (the default
		364	is enabled) gives you the most portable way of getting urgent data, by
		365	putting it into the stream.
		366
		367	Since BSD emulation of OOB data on top of TCP's urgent data can have
		368	security implications, AnyEvent::Handle sets this flag automatically
		369	unless explicitly specified. Note that setting this flag after
		370	establishing a connection I<may> be a bit too late (data loss could
		371	already have occured on BSD systems), but at least it will protect you
		372	from most attacks.
		373
127	=item read_size => <bytes>	374	=item read_size => <bytes>
128		375
129	The default read block size (the amount of bytes this module will try to read	376	The initial read block size, the number of bytes this module will try
130	on each [loop iteration). Default: C<4096>.	377	to read during each loop iteration. Each handle object will consume
		378	at least this amount of memory for the read buffer as well, so when
		379	handling many connections watch out for memory requirements). See also
		380	C<max_read_size>. Default: C<2048>.
		381
		382	=item max_read_size => <bytes>
		383
		384	The maximum read buffer size used by the dynamic adjustment
		385	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		386	one go it will double C<read_size> up to the maximum given by this
		387	option. Default: C<131072> or C<read_size>, whichever is higher.
131		388
132	=item low_water_mark => <bytes>	389	=item low_water_mark => <bytes>
133		390
134	Sets the amount of bytes (default: C<0>) that make up an "empty" write	391	Sets the number of bytes (default: C<0>) that make up an "empty" write
135	buffer: If the write reaches this size or gets even samller it is	392	buffer: If the buffer reaches this size or gets even samller it is
136	considered empty.	393	considered empty.
		394
		395	Sometimes it can be beneficial (for performance reasons) to add data to
		396	the write buffer before it is fully drained, but this is a rare case, as
		397	the operating system kernel usually buffers data as well, so the default
		398	is good in almost all cases.
		399
		400	=item linger => <seconds>
		401
		402	If this is non-zero (default: C<3600>), the destructor of the
		403	AnyEvent::Handle object will check whether there is still outstanding
		404	write data and will install a watcher that will write this data to the
		405	socket. No errors will be reported (this mostly matches how the operating
		406	system treats outstanding data at socket close time).
		407
		408	This will not work for partial TLS data that could not be encoded
		409	yet. This data will be lost. Calling the C<stoptls> method in time might
		410	help.
		411
		412	=item peername => $string
		413
		414	A string used to identify the remote site - usually the DNS hostname
		415	(I<not> IDN!) used to create the connection, rarely the IP address.
		416
		417	Apart from being useful in error messages, this string is also used in TLS
		418	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		419	verification will be skipped when C<peername> is not specified or is
		420	C<undef>.
		421
		422	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		423
		424	When this parameter is given, it enables TLS (SSL) mode, that means
		425	AnyEvent will start a TLS handshake as soon as the connection has been
		426	established and will transparently encrypt/decrypt data afterwards.
		427
		428	All TLS protocol errors will be signalled as C<EPROTO>, with an
		429	appropriate error message.
		430
		431	TLS mode requires Net::SSLeay to be installed (it will be loaded
		432	automatically when you try to create a TLS handle): this module doesn't
		433	have a dependency on that module, so if your module requires it, you have
		434	to add the dependency yourself. If Net::SSLeay cannot be loaded or is too
		435	old, you get an C<EPROTO> error.
		436
		437	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		438	C<accept>, and for the TLS client side of a connection, use C<connect>
		439	mode.
		440
		441	You can also provide your own TLS connection object, but you have
		442	to make sure that you call either C<Net::SSLeay::set_connect_state>
		443	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		444	AnyEvent::Handle. Also, this module will take ownership of this connection
		445	object.
		446
		447	At some future point, AnyEvent::Handle might switch to another TLS
		448	implementation, then the option to use your own session object will go
		449	away.
		450
		451	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		452	passing in the wrong integer will lead to certain crash. This most often
		453	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		454	segmentation fault.
		455
		456	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
		457
		458	=item tls_ctx => $anyevent_tls
		459
		460	Use the given C<AnyEvent::TLS> object to create the new TLS connection
		461	(unless a connection object was specified directly). If this
		462	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		463	C<AnyEvent::Handle::TLS_CTX>.
		464
		465	Instead of an object, you can also specify a hash reference with C<< key
		466	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		467	new TLS context object.
		468
		469	=item on_starttls => $cb->($handle, $success[, $error_message])
		470
		471	This callback will be invoked when the TLS/SSL handshake has finished. If
		472	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		473	(C<on_stoptls> will not be called in this case).
		474
		475	The session in C<< $handle->{tls} >> can still be examined in this
		476	callback, even when the handshake was not successful.
		477
		478	TLS handshake failures will not cause C<on_error> to be invoked when this
		479	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		480
		481	Without this callback, handshake failures lead to C<on_error> being
		482	called as usual.
		483
		484	Note that you cannot just call C<starttls> again in this callback. If you
		485	need to do that, start an zero-second timer instead whose callback can
		486	then call C<< ->starttls >> again.
		487
		488	=item on_stoptls => $cb->($handle)
		489
		490	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		491	set, then it will be invoked after freeing the TLS session. If it is not,
		492	then a TLS shutdown condition will be treated like a normal EOF condition
		493	on the handle.
		494
		495	The session in C<< $handle->{tls} >> can still be examined in this
		496	callback.
		497
		498	This callback will only be called on TLS shutdowns, not when the
		499	underlying handle signals EOF.
		500
		501	=item json => JSON or JSON::XS object
		502
		503	This is the json coder object used by the C<json> read and write types.
		504
		505	If you don't supply it, then AnyEvent::Handle will create and use a
		506	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		507	texts.
		508
		509	Note that you are responsible to depend on the JSON module if you want to
		510	use this functionality, as AnyEvent does not have a dependency itself.
137		511
138	=back	512	=back
139		513
140	=cut	514	=cut
141		515
142	sub new {	516	sub new {
143	my $class = shift;	517	my $class = shift;
144
145	my $self = bless { @_ }, $class;	518	my $self = bless { @_ }, $class;
146		519
147	$self->{fh} or Carp::croak "mandatory argument fh is missing";	520	if ($self->{fh}) {
		521	$self->_start;
		522	return unless $self->{fh}; # could be gone by now
		523
		524	} elsif ($self->{connect}) {
		525	require AnyEvent::Socket;
		526
		527	$self->{peername} = $self->{connect}[0]
		528	unless exists $self->{peername};
		529
		530	$self->{_skip_drain_rbuf} = 1;
		531
		532	{
		533	Scalar::Util::weaken (my $self = $self);
		534
		535	$self->{_connect} =
		536	AnyEvent::Socket::tcp_connect (
		537	$self->{connect}[0],
		538	$self->{connect}[1],
		539	sub {
		540	my ($fh, $host, $port, $retry) = @_;
		541
		542	delete $self->{_connect}; # no longer needed
		543
		544	if ($fh) {
		545	$self->{fh} = $fh;
		546
		547	delete $self->{_skip_drain_rbuf};
		548	$self->_start;
		549
		550	$self->{on_connect}
		551	and $self->{on_connect}($self, $host, $port, sub {
		552	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		553	$self->{_skip_drain_rbuf} = 1;
		554	&$retry;
		555	});
		556
		557	} else {
		558	if ($self->{on_connect_error}) {
		559	$self->{on_connect_error}($self, "$!");
		560	$self->destroy if $self;
		561	} else {
		562	$self->_error ($!, 1);
		563	}
		564	}
		565	},
		566	sub {
		567	local $self->{fh} = $_[0];
		568
		569	$self->{on_prepare}
		570	? $self->{on_prepare}->($self)
		571	: ()
		572	}
		573	);
		574	}
		575
		576	} else {
		577	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		578	}
		579
		580	$self
		581	}
		582
		583	sub _start {
		584	my ($self) = @_;
		585
		586	# too many clueless people try to use udp and similar sockets
		587	# with AnyEvent::Handle, do them a favour.
		588	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		589	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		590	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
148		591
149	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	592	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
150		593
151	$self->on_eof ((delete $self->{on_eof} ) or Carp::croak "mandatory argument on_eof is missing");	594	$self->{_activity} =
		595	$self->{_ractivity} =
		596	$self->{_wactivity} = AE::now;
152		597
153	$self->on_error (delete $self->{on_error}) if $self->{on_error};	598	$self->{read_size} ||= 2048;
		599	$self->{max_read_size} = $self->{read_size}
		600	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		601
		602	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		603	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		604	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		605
		606	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		607	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		608
		609	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		610
		611	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		612	if $self->{tls};
		613
154	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	614	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
155	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
156		615
157	$self->start_read;	616	$self->start_read
		617	if $self->{on_read} || @{ $self->{_queue} };
158		618
159	$self	619	$self->_drain_wbuf;
160	}	620	}
161		621
162	sub _shutdown {
163	my ($self) = @_;
164
165	delete $self->{rw};
166	delete $self->{ww};
167	delete $self->{fh};
168	}
169
170	sub error {	622	sub _error {
171	my ($self) = @_;	623	my ($self, $errno, $fatal, $message) = @_;
172		624
173	{	625	$! = $errno;
174	local $!;	626	$message ||= "$!";
175	$self->_shutdown;
176	}
177		627
178	if ($self->{on_error}) {	628	if ($self->{on_error}) {
179	$self->{on_error}($self);	629	$self->{on_error}($self, $fatal, $message);
180	} else {	630	$self->destroy if $fatal;
		631	} elsif ($self->{fh} || $self->{connect}) {
		632	$self->destroy;
181	die "AnyEvent::Handle uncaught fatal error: $!";	633	Carp::croak "AnyEvent::Handle uncaught error: $message";
182	}	634	}
183	}	635	}
184		636
185	=item $fh = $handle->fh	637	=item $fh = $handle->fh
186		638
187	This method returns the filehandle of the L<AnyEvent::Handle> object.	639	This method returns the file handle used to create the L<AnyEvent::Handle> object.
188		640
189	=cut	641	=cut
190		642
191	sub fh { $_[0]->{fh} }	643	sub fh { $_[0]{fh} }
192		644
193	=item $handle->on_error ($cb)	645	=item $handle->on_error ($cb)
194		646
195	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	647	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
196		648
…		…
208		660
209	sub on_eof {	661	sub on_eof {
210	$_[0]{on_eof} = $_[1];	662	$_[0]{on_eof} = $_[1];
211	}	663	}
212		664
		665	=item $handle->on_timeout ($cb)
		666
		667	=item $handle->on_rtimeout ($cb)
		668
		669	=item $handle->on_wtimeout ($cb)
		670
		671	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		672	callback, or disables the callback (but not the timeout) if C<$cb> =
		673	C<undef>. See the C<timeout> constructor argument and method.
		674
		675	=cut
		676
		677	# see below
		678
		679	=item $handle->autocork ($boolean)
		680
		681	Enables or disables the current autocork behaviour (see C<autocork>
		682	constructor argument). Changes will only take effect on the next write.
		683
		684	=cut
		685
		686	sub autocork {
		687	$_[0]{autocork} = $_[1];
		688	}
		689
		690	=item $handle->no_delay ($boolean)
		691
		692	Enables or disables the C<no_delay> setting (see constructor argument of
		693	the same name for details).
		694
		695	=cut
		696
		697	sub no_delay {
		698	$_[0]{no_delay} = $_[1];
		699
		700	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		701	if $_[0]{fh};
		702	}
		703
		704	=item $handle->keepalive ($boolean)
		705
		706	Enables or disables the C<keepalive> setting (see constructor argument of
		707	the same name for details).
		708
		709	=cut
		710
		711	sub keepalive {
		712	$_[0]{keepalive} = $_[1];
		713
		714	eval {
		715	local $SIG{__DIE__};
		716	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		717	if $_[0]{fh};
		718	};
		719	}
		720
		721	=item $handle->oobinline ($boolean)
		722
		723	Enables or disables the C<oobinline> setting (see constructor argument of
		724	the same name for details).
		725
		726	=cut
		727
		728	sub oobinline {
		729	$_[0]{oobinline} = $_[1];
		730
		731	eval {
		732	local $SIG{__DIE__};
		733	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		734	if $_[0]{fh};
		735	};
		736	}
		737
		738	=item $handle->keepalive ($boolean)
		739
		740	Enables or disables the C<keepalive> setting (see constructor argument of
		741	the same name for details).
		742
		743	=cut
		744
		745	sub keepalive {
		746	$_[0]{keepalive} = $_[1];
		747
		748	eval {
		749	local $SIG{__DIE__};
		750	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		751	if $_[0]{fh};
		752	};
		753	}
		754
		755	=item $handle->on_starttls ($cb)
		756
		757	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		758
		759	=cut
		760
		761	sub on_starttls {
		762	$_[0]{on_starttls} = $_[1];
		763	}
		764
		765	=item $handle->on_stoptls ($cb)
		766
		767	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		768
		769	=cut
		770
		771	sub on_stoptls {
		772	$_[0]{on_stoptls} = $_[1];
		773	}
		774
		775	=item $handle->rbuf_max ($max_octets)
		776
		777	Configures the C<rbuf_max> setting (C<undef> disables it).
		778
		779	=item $handle->wbuf_max ($max_octets)
		780
		781	Configures the C<wbuf_max> setting (C<undef> disables it).
		782
		783	=cut
		784
		785	sub rbuf_max {
		786	$_[0]{rbuf_max} = $_[1];
		787	}
		788
		789	sub wbuf_max {
		790	$_[0]{wbuf_max} = $_[1];
		791	}
		792
		793	#############################################################################
		794
		795	=item $handle->timeout ($seconds)
		796
		797	=item $handle->rtimeout ($seconds)
		798
		799	=item $handle->wtimeout ($seconds)
		800
		801	Configures (or disables) the inactivity timeout.
		802
		803	The timeout will be checked instantly, so this method might destroy the
		804	handle before it returns.
		805
		806	=item $handle->timeout_reset
		807
		808	=item $handle->rtimeout_reset
		809
		810	=item $handle->wtimeout_reset
		811
		812	Reset the activity timeout, as if data was received or sent.
		813
		814	These methods are cheap to call.
		815
		816	=cut
		817
		818	for my $dir ("", "r", "w") {
		819	my $timeout = "${dir}timeout";
		820	my $tw = "_${dir}tw";
		821	my $on_timeout = "on_${dir}timeout";
		822	my $activity = "_${dir}activity";
		823	my $cb;
		824
		825	*$on_timeout = sub {
		826	$_[0]{$on_timeout} = $_[1];
		827	};
		828
		829	*$timeout = sub {
		830	my ($self, $new_value) = @_;
		831
		832	$new_value >= 0
		833	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		834
		835	$self->{$timeout} = $new_value;
		836	delete $self->{$tw}; &$cb;
		837	};
		838
		839	*{"${dir}timeout_reset"} = sub {
		840	$_[0]{$activity} = AE::now;
		841	};
		842
		843	# main workhorse:
		844	# reset the timeout watcher, as neccessary
		845	# also check for time-outs
		846	$cb = sub {
		847	my ($self) = @_;
		848
		849	if ($self->{$timeout} && $self->{fh}) {
		850	my $NOW = AE::now;
		851
		852	# when would the timeout trigger?
		853	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		854
		855	# now or in the past already?
		856	if ($after <= 0) {
		857	$self->{$activity} = $NOW;
		858
		859	if ($self->{$on_timeout}) {
		860	$self->{$on_timeout}($self);
		861	} else {
		862	$self->_error (Errno::ETIMEDOUT);
		863	}
		864
		865	# callback could have changed timeout value, optimise
		866	return unless $self->{$timeout};
		867
		868	# calculate new after
		869	$after = $self->{$timeout};
		870	}
		871
		872	Scalar::Util::weaken $self;
		873	return unless $self; # ->error could have destroyed $self
		874
		875	$self->{$tw} ||= AE::timer $after, 0, sub {
		876	delete $self->{$tw};
		877	$cb->($self);
		878	};
		879	} else {
		880	delete $self->{$tw};
		881	}
		882	}
		883	}
		884
213	#############################################################################	885	#############################################################################
214		886
215	=back	887	=back
216		888
217	=head2 WRITE QUEUE	889	=head2 WRITE QUEUE
…		…
220	for reading.	892	for reading.
221		893
222	The write queue is very simple: you can add data to its end, and	894	The write queue is very simple: you can add data to its end, and
223	AnyEvent::Handle will automatically try to get rid of it for you.	895	AnyEvent::Handle will automatically try to get rid of it for you.
224		896
225	When data could be writtena nd the write buffer is shorter then the low	897	When data could be written and the write buffer is shorter then the low
226	water mark, the C<on_drain> callback will be invoked.	898	water mark, the C<on_drain> callback will be invoked once.
227		899
228	=over 4	900	=over 4
229		901
230	=item $handle->on_drain ($cb)	902	=item $handle->on_drain ($cb)
231		903
232	Sets the C<on_drain> callback or clears it (see the description of	904	Sets the C<on_drain> callback or clears it (see the description of
233	C<on_drain> in the constructor).	905	C<on_drain> in the constructor).
234		906
		907	This method may invoke callbacks (and therefore the handle might be
		908	destroyed after it returns).
		909
235	=cut	910	=cut
236		911
237	sub on_drain {	912	sub on_drain {
238	my ($self, $cb) = @_;	913	my ($self, $cb) = @_;
239		914
240	$self->{on_drain} = $cb;	915	$self->{on_drain} = $cb;
241		916
242	$cb->($self)	917	$cb->($self)
243	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	918	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
244	}	919	}
245		920
246	=item $handle->push_write ($data)	921	=item $handle->push_write ($data)
247		922
248	Queues the given scalar to be written. You can push as much data as you	923	Queues the given scalar to be written. You can push as much data as
249	want (only limited by the available memory), as C<AnyEvent::Handle>	924	you want (only limited by the available memory and C<wbuf_max>), as
250	buffers it independently of the kernel.	925	C<AnyEvent::Handle> buffers it independently of the kernel.
251		926
252	=cut	927	This method may invoke callbacks (and therefore the handle might be
		928	destroyed after it returns).
253		929
254	sub push_write {	930	=cut
		931
		932	sub _drain_wbuf {
255	my ($self, $data) = @_;	933	my ($self) = @_;
256		934
257	$self->{wbuf} .= $data;	935	if (!$self->{_ww} && length $self->{wbuf}) {
258		936
259	unless ($self->{ww}) {
260	Scalar::Util::weaken $self;	937	Scalar::Util::weaken $self;
		938
261	my $cb = sub {	939	my $cb = sub {
262	my $len = syswrite $self->{fh}, $self->{wbuf};	940	my $len = syswrite $self->{fh}, $self->{wbuf};
263		941
264	if ($len > 0) {	942	if (defined $len) {
265	substr $self->{wbuf}, 0, $len, "";	943	substr $self->{wbuf}, 0, $len, "";
266		944
		945	$self->{_activity} = $self->{_wactivity} = AE::now;
267		946
268	$self->{on_drain}($self)	947	$self->{on_drain}($self)
269	if $self->{low_water_mark} >= length $self->{wbuf}	948	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
270	&& $self->{on_drain};	949	&& $self->{on_drain};
271		950
272	delete $self->{ww} unless length $self->{wbuf};	951	delete $self->{_ww} unless length $self->{wbuf};
273	} elsif ($! != EAGAIN && $! != EINTR) {	952	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
274	$self->error;	953	$self->_error ($!, 1);
275	}	954	}
276	};	955	};
277		956
278	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	957	# try to write data immediately
		958	$cb->() unless $self->{autocork};
279		959
280	$cb->($self);	960	# if still data left in wbuf, we need to poll
		961	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		962	if length $self->{wbuf};
		963
		964	if (
		965	defined $self->{wbuf_max}
		966	&& $self->{wbuf_max} < length $self->{wbuf}
		967	) {
		968	$self->_error (Errno::ENOSPC, 1), return;
		969	}
281	};	970	};
282	}	971	}
		972
		973	our %WH;
		974
		975	# deprecated
		976	sub register_write_type($$) {
		977	$WH{$_[0]} = $_[1];
		978	}
		979
		980	sub push_write {
		981	my $self = shift;
		982
		983	if (@_ > 1) {
		984	my $type = shift;
		985
		986	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
		987	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
		988	->($self, @_);
		989	}
		990
		991	# we downgrade here to avoid hard-to-track-down bugs,
		992	# and diagnose the problem earlier and better.
		993
		994	if ($self->{tls}) {
		995	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		996	&_dotls ($self) if $self->{fh};
		997	} else {
		998	utf8::downgrade $self->{wbuf} .= $_[0];
		999	$self->_drain_wbuf if $self->{fh};
		1000	}
		1001	}
		1002
		1003	=item $handle->push_write (type => @args)
		1004
		1005	Instead of formatting your data yourself, you can also let this module
		1006	do the job by specifying a type and type-specific arguments. You
		1007	can also specify the (fully qualified) name of a package, in which
		1008	case AnyEvent tries to load the package and then expects to find the
		1009	C<anyevent_write_type> function inside (see "custom write types", below).
		1010
		1011	Predefined types are (if you have ideas for additional types, feel free to
		1012	drop by and tell us):
		1013
		1014	=over 4
		1015
		1016	=item netstring => $string
		1017
		1018	Formats the given value as netstring
		1019	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		1020
		1021	=cut
		1022
		1023	register_write_type netstring => sub {
		1024	my ($self, $string) = @_;
		1025
		1026	(length $string) . ":$string,"
		1027	};
		1028
		1029	=item packstring => $format, $data
		1030
		1031	An octet string prefixed with an encoded length. The encoding C<$format>
		1032	uses the same format as a Perl C<pack> format, but must specify a single
		1033	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1034	optional C<!>, C<< < >> or C<< > >> modifier).
		1035
		1036	=cut
		1037
		1038	register_write_type packstring => sub {
		1039	my ($self, $format, $string) = @_;
		1040
		1041	pack "$format/a*", $string
		1042	};
		1043
		1044	=item json => $array_or_hashref
		1045
		1046	Encodes the given hash or array reference into a JSON object. Unless you
		1047	provide your own JSON object, this means it will be encoded to JSON text
		1048	in UTF-8.
		1049
		1050	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		1051	one end of a handle and read them at the other end without using any
		1052	additional framing.
		1053
		1054	The generated JSON text is guaranteed not to contain any newlines: While
		1055	this module doesn't need delimiters after or between JSON texts to be
		1056	able to read them, many other languages depend on that.
		1057
		1058	A simple RPC protocol that interoperates easily with others is to send
		1059	JSON arrays (or objects, although arrays are usually the better choice as
		1060	they mimic how function argument passing works) and a newline after each
		1061	JSON text:
		1062
		1063	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		1064	$handle->push_write ("\012");
		1065
		1066	An AnyEvent::Handle receiver would simply use the C<json> read type and
		1067	rely on the fact that the newline will be skipped as leading whitespace:
		1068
		1069	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1070
		1071	Other languages could read single lines terminated by a newline and pass
		1072	this line into their JSON decoder of choice.
		1073
		1074	=cut
		1075
		1076	sub json_coder() {
		1077	eval { require JSON::XS; JSON::XS->new->utf8 }
		1078	|| do { require JSON; JSON->new->utf8 }
		1079	}
		1080
		1081	register_write_type json => sub {
		1082	my ($self, $ref) = @_;
		1083
		1084	my $json = $self->{json} ||= json_coder;
		1085
		1086	$json->encode ($ref)
		1087	};
		1088
		1089	=item storable => $reference
		1090
		1091	Freezes the given reference using L<Storable> and writes it to the
		1092	handle. Uses the C<nfreeze> format.
		1093
		1094	=cut
		1095
		1096	register_write_type storable => sub {
		1097	my ($self, $ref) = @_;
		1098
		1099	require Storable unless $Storable::VERSION;
		1100
		1101	pack "w/a*", Storable::nfreeze ($ref)
		1102	};
		1103
		1104	=back
		1105
		1106	=item $handle->push_shutdown
		1107
		1108	Sometimes you know you want to close the socket after writing your data
		1109	before it was actually written. One way to do that is to replace your
		1110	C<on_drain> handler by a callback that shuts down the socket (and set
		1111	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1112	replaces the C<on_drain> callback with:
		1113
		1114	sub { shutdown $_[0]{fh}, 1 }
		1115
		1116	This simply shuts down the write side and signals an EOF condition to the
		1117	the peer.
		1118
		1119	You can rely on the normal read queue and C<on_eof> handling
		1120	afterwards. This is the cleanest way to close a connection.
		1121
		1122	This method may invoke callbacks (and therefore the handle might be
		1123	destroyed after it returns).
		1124
		1125	=cut
		1126
		1127	sub push_shutdown {
		1128	my ($self) = @_;
		1129
		1130	delete $self->{low_water_mark};
		1131	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1132	}
		1133
		1134	=item custom write types - Package::anyevent_write_type $handle, @args
		1135
		1136	Instead of one of the predefined types, you can also specify the name of
		1137	a package. AnyEvent will try to load the package and then expects to find
		1138	a function named C<anyevent_write_type> inside. If it isn't found, it
		1139	progressively tries to load the parent package until it either finds the
		1140	function (good) or runs out of packages (bad).
		1141
		1142	Whenever the given C<type> is used, C<push_write> will the function with
		1143	the handle object and the remaining arguments.
		1144
		1145	The function is supposed to return a single octet string that will be
		1146	appended to the write buffer, so you can mentally treat this function as a
		1147	"arguments to on-the-wire-format" converter.
		1148
		1149	Example: implement a custom write type C<join> that joins the remaining
		1150	arguments using the first one.
		1151
		1152	$handle->push_write (My::Type => " ", 1,2,3);
		1153
		1154	# uses the following package, which can be defined in the "My::Type" or in
		1155	# the "My" modules to be auto-loaded, or just about anywhere when the
		1156	# My::Type::anyevent_write_type is defined before invoking it.
		1157
		1158	package My::Type;
		1159
		1160	sub anyevent_write_type {
		1161	my ($handle, $delim, @args) = @_;
		1162
		1163	join $delim, @args
		1164	}
		1165
		1166	=cut
283		1167
284	#############################################################################	1168	#############################################################################
285		1169
286	=back	1170	=back
287		1171
…		…
294	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1178	ways, the "simple" way, using only C<on_read> and the "complex" way, using
295	a queue.	1179	a queue.
296		1180
297	In the simple case, you just install an C<on_read> callback and whenever	1181	In the simple case, you just install an C<on_read> callback and whenever
298	new data arrives, it will be called. You can then remove some data (if	1182	new data arrives, it will be called. You can then remove some data (if
299	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1183	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
300	or not.	1184	leave the data there if you want to accumulate more (e.g. when only a
		1185	partial message has been received so far), or change the read queue with
		1186	e.g. C<push_read>.
301		1187
302	In the more complex case, you want to queue multiple callbacks. In this	1188	In the more complex case, you want to queue multiple callbacks. In this
303	case, AnyEvent::Handle will call the first queued callback each time new	1189	case, AnyEvent::Handle will call the first queued callback each time new
304	data arrives and removes it when it has done its job (see C<push_read>,	1190	data arrives (also the first time it is queued) and remove it when it has
305	below).	1191	done its job (see C<push_read>, below).
306		1192
307	This way you can, for example, push three line-reads, followed by reading	1193	This way you can, for example, push three line-reads, followed by reading
308	a chunk of data, and AnyEvent::Handle will execute them in order.	1194	a chunk of data, and AnyEvent::Handle will execute them in order.
309		1195
310	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1196	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
311	the specified number of bytes which give an XML datagram.	1197	the specified number of bytes which give an XML datagram.
312		1198
313	# in the default state, expect some header bytes	1199	# in the default state, expect some header bytes
314	$handle->on_read (sub {	1200	$handle->on_read (sub {
315	# some data is here, now queue the length-header-read (4 octets)	1201	# some data is here, now queue the length-header-read (4 octets)
316	shift->unshift_read_chunk (4, sub {	1202	shift->unshift_read (chunk => 4, sub {
317	# header arrived, decode	1203	# header arrived, decode
318	my $len = unpack "N", $_[1];	1204	my $len = unpack "N", $_[1];
319		1205
320	# now read the payload	1206	# now read the payload
321	shift->unshift_read_chunk ($len, sub {	1207	shift->unshift_read (chunk => $len, sub {
322	my $xml = $_[1];	1208	my $xml = $_[1];
323	# handle xml	1209	# handle xml
324	});	1210	});
325	});	1211	});
326	});	1212	});
327		1213
328	Example 2: Implement a client for a protocol that replies either with	1214	Example 2: Implement a client for a protocol that replies either with "OK"
329	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1215	and another line or "ERROR" for the first request that is sent, and 64
330	second request. Due tot he availability of a full queue, we can just	1216	bytes for the second request. Due to the availability of a queue, we can
331	pipeline sending both requests and manipulate the queue as necessary in	1217	just pipeline sending both requests and manipulate the queue as necessary
332	the callbacks:	1218	in the callbacks.
333		1219
334	# request one	1220	When the first callback is called and sees an "OK" response, it will
		1221	C<unshift> another line-read. This line-read will be queued I<before> the
		1222	64-byte chunk callback.
		1223
		1224	# request one, returns either "OK + extra line" or "ERROR"
335	$handle->push_write ("request 1\015\012");	1225	$handle->push_write ("request 1\015\012");
336		1226
337	# we expect "ERROR" or "OK" as response, so push a line read	1227	# we expect "ERROR" or "OK" as response, so push a line read
338	$handle->push_read_line (sub {	1228	$handle->push_read (line => sub {
339	# if we got an "OK", we have to _prepend_ another line,	1229	# if we got an "OK", we have to _prepend_ another line,
340	# so it will be read before the second request reads its 64 bytes	1230	# so it will be read before the second request reads its 64 bytes
341	# which are already in the queue when this callback is called	1231	# which are already in the queue when this callback is called
342	# we don't do this in case we got an error	1232	# we don't do this in case we got an error
343	if ($_[1] eq "OK") {	1233	if ($_[1] eq "OK") {
344	$_[0]->unshift_read_line (sub {	1234	$_[0]->unshift_read (line => sub {
345	my $response = $_[1];	1235	my $response = $_[1];
346	...	1236	...
347	});	1237	});
348	}	1238	}
349	});	1239	});
350		1240
351	# request two	1241	# request two, simply returns 64 octets
352	$handle->push_write ("request 2\015\012");	1242	$handle->push_write ("request 2\015\012");
353		1243
354	# simply read 64 bytes, always	1244	# simply read 64 bytes, always
355	$handle->push_read_chunk (64, sub {	1245	$handle->push_read (chunk => 64, sub {
356	my $response = $_[1];	1246	my $response = $_[1];
357	...	1247	...
358	});	1248	});
359		1249
360	=over 4	1250	=over 4
…		…
362	=cut	1252	=cut
363		1253
364	sub _drain_rbuf {	1254	sub _drain_rbuf {
365	my ($self) = @_;	1255	my ($self) = @_;
366		1256
		1257	# avoid recursion
367	return if $self->{in_drain};	1258	return if $self->{_skip_drain_rbuf};
368	local $self->{in_drain} = 1;	1259	local $self->{_skip_drain_rbuf} = 1;
369		1260
		1261	while () {
		1262	# we need to use a separate tls read buffer, as we must not receive data while
		1263	# we are draining the buffer, and this can only happen with TLS.
		1264	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1265	if exists $self->{_tls_rbuf};
		1266
370	while (my $len = length $self->{rbuf}) {	1267	my $len = length $self->{rbuf};
371	no strict 'refs';	1268
372	if (my $cb = shift @{ $self->{queue} }) {	1269	if (my $cb = shift @{ $self->{_queue} }) {
373	if (!$cb->($self)) {	1270	unless ($cb->($self)) {
		1271	# no progress can be made
		1272	# (not enough data and no data forthcoming)
		1273	$self->_error (Errno::EPIPE, 1), return
374	if ($self->{eof}) {	1274	if $self->{_eof};
375	# no progress can be made (not enough data and no data forthcoming)
376	$! = &Errno::EPIPE; return $self->error;
377	}
378		1275
379	unshift @{ $self->{queue} }, $cb;	1276	unshift @{ $self->{_queue} }, $cb;
380	return;	1277	last;
381	}	1278	}
382	} elsif ($self->{on_read}) {	1279	} elsif ($self->{on_read}) {
		1280	last unless $len;
		1281
383	$self->{on_read}($self);	1282	$self->{on_read}($self);
384		1283
385	if (	1284	if (
386	$self->{eof} # if no further data will arrive
387	&& $len == length $self->{rbuf} # and no data has been consumed	1285	$len == length $self->{rbuf} # if no data has been consumed
388	&& !@{ $self->{queue} } # and the queue is still empty	1286	&& !@{ $self->{_queue} } # and the queue is still empty
389	&& $self->{on_read} # and we still want to read data	1287	&& $self->{on_read} # but we still have on_read
390	) {	1288	) {
		1289	# no further data will arrive
391	# then no progress can be made	1290	# so no progress can be made
392	$! = &Errno::EPIPE; return $self->error;	1291	$self->_error (Errno::EPIPE, 1), return
		1292	if $self->{_eof};
		1293
		1294	last; # more data might arrive
393	}	1295	}
394	} else {	1296	} else {
395	# read side becomes idle	1297	# read side becomes idle
396	delete $self->{rw};	1298	delete $self->{_rw} unless $self->{tls};
397	return;	1299	last;
398	}	1300	}
399	}	1301	}
400		1302
401	if ($self->{eof}) {	1303	if ($self->{_eof}) {
402	$self->_shutdown;	1304	$self->{on_eof}
403	$self->{on_eof}($self);	1305	? $self->{on_eof}($self)
		1306	: $self->_error (0, 1, "Unexpected end-of-file");
		1307
		1308	return;
		1309	}
		1310
		1311	if (
		1312	defined $self->{rbuf_max}
		1313	&& $self->{rbuf_max} < length $self->{rbuf}
		1314	) {
		1315	$self->_error (Errno::ENOSPC, 1), return;
		1316	}
		1317
		1318	# may need to restart read watcher
		1319	unless ($self->{_rw}) {
		1320	$self->start_read
		1321	if $self->{on_read} || @{ $self->{_queue} };
404	}	1322	}
405	}	1323	}
406		1324
407	=item $handle->on_read ($cb)	1325	=item $handle->on_read ($cb)
408		1326
409	This replaces the currently set C<on_read> callback, or clears it (when	1327	This replaces the currently set C<on_read> callback, or clears it (when
410	the new callback is C<undef>). See the description of C<on_read> in the	1328	the new callback is C<undef>). See the description of C<on_read> in the
411	constructor.	1329	constructor.
412		1330
		1331	This method may invoke callbacks (and therefore the handle might be
		1332	destroyed after it returns).
		1333
413	=cut	1334	=cut
414		1335
415	sub on_read {	1336	sub on_read {
416	my ($self, $cb) = @_;	1337	my ($self, $cb) = @_;
417		1338
418	$self->{on_read} = $cb;	1339	$self->{on_read} = $cb;
		1340	$self->_drain_rbuf if $cb;
419	}	1341	}
420		1342
421	=item $handle->rbuf	1343	=item $handle->rbuf
422		1344
423	Returns the read buffer (as a modifiable lvalue).	1345	Returns the read buffer (as a modifiable lvalue). You can also access the
		1346	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1347	much faster, and no less clean).
424		1348
425	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1349	The only operation allowed on the read buffer (apart from looking at it)
426	you want.	1350	is removing data from its beginning. Otherwise modifying or appending to
		1351	it is not allowed and will lead to hard-to-track-down bugs.
427		1352
428	NOTE: The read buffer should only be used or modified if the C<on_read>,	1353	NOTE: The read buffer should only be used or modified in the C<on_read>
429	C<push_read> or C<unshift_read> methods are used. The other read methods	1354	callback or when C<push_read> or C<unshift_read> are used with a single
430	automatically manage the read buffer.	1355	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1356	will manage the read buffer on their own.
431		1357
432	=cut	1358	=cut
433		1359
434	sub rbuf : lvalue {	1360	sub rbuf : lvalue {
435	$_[0]{rbuf}	1361	$_[0]{rbuf}
…		…
442	Append the given callback to the end of the queue (C<push_read>) or	1368	Append the given callback to the end of the queue (C<push_read>) or
443	prepend it (C<unshift_read>).	1369	prepend it (C<unshift_read>).
444		1370
445	The callback is called each time some additional read data arrives.	1371	The callback is called each time some additional read data arrives.
446		1372
447	It must check wether enough data is in the read buffer already.	1373	It must check whether enough data is in the read buffer already.
448		1374
449	If not enough data is available, it must return the empty list or a false	1375	If not enough data is available, it must return the empty list or a false
450	value, in which case it will be called repeatedly until enough data is	1376	value, in which case it will be called repeatedly until enough data is
451	available (or an error condition is detected).	1377	available (or an error condition is detected).
452		1378
453	If enough data was available, then the callback must remove all data it is	1379	If enough data was available, then the callback must remove all data it is
454	interested in (which can be none at all) and return a true value. After returning	1380	interested in (which can be none at all) and return a true value. After returning
455	true, it will be removed from the queue.	1381	true, it will be removed from the queue.
456		1382
		1383	These methods may invoke callbacks (and therefore the handle might be
		1384	destroyed after it returns).
		1385
457	=cut	1386	=cut
		1387
		1388	our %RH;
		1389
		1390	sub register_read_type($$) {
		1391	$RH{$_[0]} = $_[1];
		1392	}
458		1393
459	sub push_read {	1394	sub push_read {
460	my ($self, $cb) = @_;	1395	my $self = shift;
		1396	my $cb = pop;
461		1397
		1398	if (@_) {
		1399	my $type = shift;
		1400
		1401	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1402	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
		1403	->($self, $cb, @_);
		1404	}
		1405
462	push @{ $self->{queue} }, $cb;	1406	push @{ $self->{_queue} }, $cb;
463	$self->_drain_rbuf;	1407	$self->_drain_rbuf;
464	}	1408	}
465		1409
466	sub unshift_read {	1410	sub unshift_read {
467	my ($self, $cb) = @_;	1411	my $self = shift;
		1412	my $cb = pop;
468		1413
		1414	if (@_) {
		1415	my $type = shift;
		1416
		1417	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1418	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
		1419	->($self, $cb, @_);
		1420	}
		1421
469	push @{ $self->{queue} }, $cb;	1422	unshift @{ $self->{_queue} }, $cb;
470	$self->_drain_rbuf;	1423	$self->_drain_rbuf;
471	}	1424	}
472		1425
473	=item $handle->push_read_chunk ($len, $cb->($self, $data))	1426	=item $handle->push_read (type => @args, $cb)
474		1427
475	=item $handle->unshift_read_chunk ($len, $cb->($self, $data))	1428	=item $handle->unshift_read (type => @args, $cb)
476		1429
477	Append the given callback to the end of the queue (C<push_read_chunk>) or	1430	Instead of providing a callback that parses the data itself you can chose
478	prepend it (C<unshift_read_chunk>).	1431	between a number of predefined parsing formats, for chunks of data, lines
		1432	etc. You can also specify the (fully qualified) name of a package, in
		1433	which case AnyEvent tries to load the package and then expects to find the
		1434	C<anyevent_read_type> function inside (see "custom read types", below).
479		1435
480	The callback will be called only once C<$len> bytes have been read, and	1436	Predefined types are (if you have ideas for additional types, feel free to
481	these C<$len> bytes will be passed to the callback.	1437	drop by and tell us):
482		1438
483	=cut	1439	=over 4
484		1440
485	sub _read_chunk($$) {	1441	=item chunk => $octets, $cb->($handle, $data)
		1442
		1443	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1444	data read to the callback. The callback will never be called with less
		1445	data.
		1446
		1447	Example: read 2 bytes.
		1448
		1449	$handle->push_read (chunk => 2, sub {
		1450	say "yay " . unpack "H*", $_[1];
		1451	});
		1452
		1453	=cut
		1454
		1455	register_read_type chunk => sub {
486	my ($self, $len, $cb) = @_;	1456	my ($self, $cb, $len) = @_;
487		1457
488	sub {	1458	sub {
489	$len <= length $_[0]{rbuf} or return;	1459	$len <= length $_[0]{rbuf} or return;
490	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1460	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
491	1	1461	1
492	}	1462	}
493	}	1463	};
494		1464
495	sub push_read_chunk {	1465	=item line => [$eol, ]$cb->($handle, $line, $eol)
496	$_[0]->push_read (&_read_chunk);
497	}
498
499
500	sub unshift_read_chunk {
501	$_[0]->unshift_read (&_read_chunk);
502	}
503
504	=item $handle->push_read_line ([$eol, ]$cb->($self, $line, $eol))
505
506	=item $handle->unshift_read_line ([$eol, ]$cb->($self, $line, $eol))
507
508	Append the given callback to the end of the queue (C<push_read_line>) or
509	prepend it (C<unshift_read_line>).
510		1466
511	The callback will be called only once a full line (including the end of	1467	The callback will be called only once a full line (including the end of
512	line marker, C<$eol>) has been read. This line (excluding the end of line	1468	line marker, C<$eol>) has been read. This line (excluding the end of line
513	marker) will be passed to the callback as second argument (C<$line>), and	1469	marker) will be passed to the callback as second argument (C<$line>), and
514	the end of line marker as the third argument (C<$eol>).	1470	the end of line marker as the third argument (C<$eol>).
…		…
525	Partial lines at the end of the stream will never be returned, as they are	1481	Partial lines at the end of the stream will never be returned, as they are
526	not marked by the end of line marker.	1482	not marked by the end of line marker.
527		1483
528	=cut	1484	=cut
529		1485
530	sub _read_line($$) {	1486	register_read_type line => sub {
531	my $self = shift;	1487	my ($self, $cb, $eol) = @_;
532	my $cb = pop;
533	my $eol = @_ ? shift : qr|(\015?\012)|;
534	my $pos;
535		1488
		1489	if (@_ < 3) {
		1490	# this is more than twice as fast as the generic code below
		1491	sub {
		1492	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1493
		1494	$cb->($_[0], "$1", "$2");
		1495	1
		1496	}
		1497	} else {
536	$eol = qr|(\Q$eol\E)| unless ref $eol;	1498	$eol = quotemeta $eol unless ref $eol;
537	$eol = qr|^(.*?)($eol)|;	1499	$eol = qr|^(.*?)($eol)|s;
		1500
		1501	sub {
		1502	$_[0]{rbuf} =~ s/$eol// or return;
		1503
		1504	$cb->($_[0], "$1", "$2");
		1505	1
		1506	}
		1507	}
		1508	};
		1509
		1510	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1511
		1512	Makes a regex match against the regex object C<$accept> and returns
		1513	everything up to and including the match.
		1514
		1515	Example: read a single line terminated by '\n'.
		1516
		1517	$handle->push_read (regex => qr<\n>, sub { ... });
		1518
		1519	If C<$reject> is given and not undef, then it determines when the data is
		1520	to be rejected: it is matched against the data when the C<$accept> regex
		1521	does not match and generates an C<EBADMSG> error when it matches. This is
		1522	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1523	receive buffer overflow).
		1524
		1525	Example: expect a single decimal number followed by whitespace, reject
		1526	anything else (not the use of an anchor).
		1527
		1528	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1529
		1530	If C<$skip> is given and not C<undef>, then it will be matched against
		1531	the receive buffer when neither C<$accept> nor C<$reject> match,
		1532	and everything preceding and including the match will be accepted
		1533	unconditionally. This is useful to skip large amounts of data that you
		1534	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1535	have to start matching from the beginning. This is purely an optimisation
		1536	and is usually worth it only when you expect more than a few kilobytes.
		1537
		1538	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1539	expect the header to be very large (it isn't in practice, but...), we use
		1540	a skip regex to skip initial portions. The skip regex is tricky in that
		1541	it only accepts something not ending in either \015 or \012, as these are
		1542	required for the accept regex.
		1543
		1544	$handle->push_read (regex =>
		1545	qr<\015\012\015\012>,
		1546	undef, # no reject
		1547	qr<^.*[^\015\012]>,
		1548	sub { ... });
		1549
		1550	=cut
		1551
		1552	register_read_type regex => sub {
		1553	my ($self, $cb, $accept, $reject, $skip) = @_;
		1554
		1555	my $data;
		1556	my $rbuf = \$self->{rbuf};
538		1557
539	sub {	1558	sub {
540	$_[0]{rbuf} =~ s/$eol// or return;	1559	# accept
541		1560	if ($$rbuf =~ $accept) {
		1561	$data .= substr $$rbuf, 0, $+[0], "";
542	$cb->($_[0], $1, $2);	1562	$cb->($_[0], $data);
		1563	return 1;
		1564	}
		1565
		1566	# reject
		1567	if ($reject && $$rbuf =~ $reject) {
		1568	$_[0]->_error (Errno::EBADMSG);
		1569	}
		1570
		1571	# skip
		1572	if ($skip && $$rbuf =~ $skip) {
		1573	$data .= substr $$rbuf, 0, $+[0], "";
		1574	}
		1575
		1576	()
		1577	}
		1578	};
		1579
		1580	=item netstring => $cb->($handle, $string)
		1581
		1582	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1583
		1584	Throws an error with C<$!> set to EBADMSG on format violations.
		1585
		1586	=cut
		1587
		1588	register_read_type netstring => sub {
		1589	my ($self, $cb) = @_;
		1590
		1591	sub {
		1592	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1593	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1594	$_[0]->_error (Errno::EBADMSG);
		1595	}
		1596	return;
		1597	}
		1598
		1599	my $len = $1;
		1600
		1601	$_[0]->unshift_read (chunk => $len, sub {
		1602	my $string = $_[1];
		1603	$_[0]->unshift_read (chunk => 1, sub {
		1604	if ($_[1] eq ",") {
		1605	$cb->($_[0], $string);
		1606	} else {
		1607	$_[0]->_error (Errno::EBADMSG);
		1608	}
		1609	});
		1610	});
		1611
543	1	1612	1
544	}	1613	}
545	}	1614	};
546		1615
547	sub push_read_line {	1616	=item packstring => $format, $cb->($handle, $string)
548	$_[0]->push_read (&_read_line);
549	}
550		1617
551	sub unshift_read_line {	1618	An octet string prefixed with an encoded length. The encoding C<$format>
552	$_[0]->unshift_read (&_read_line);	1619	uses the same format as a Perl C<pack> format, but must specify a single
553	}	1620	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1621	optional C<!>, C<< < >> or C<< > >> modifier).
		1622
		1623	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1624	EPP uses a prefix of C<N> (4 octtes).
		1625
		1626	Example: read a block of data prefixed by its length in BER-encoded
		1627	format (very efficient).
		1628
		1629	$handle->push_read (packstring => "w", sub {
		1630	my ($handle, $data) = @_;
		1631	});
		1632
		1633	=cut
		1634
		1635	register_read_type packstring => sub {
		1636	my ($self, $cb, $format) = @_;
		1637
		1638	sub {
		1639	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1640	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1641	or return;
		1642
		1643	$format = length pack $format, $len;
		1644
		1645	# bypass unshift if we already have the remaining chunk
		1646	if ($format + $len <= length $_[0]{rbuf}) {
		1647	my $data = substr $_[0]{rbuf}, $format, $len;
		1648	substr $_[0]{rbuf}, 0, $format + $len, "";
		1649	$cb->($_[0], $data);
		1650	} else {
		1651	# remove prefix
		1652	substr $_[0]{rbuf}, 0, $format, "";
		1653
		1654	# read remaining chunk
		1655	$_[0]->unshift_read (chunk => $len, $cb);
		1656	}
		1657
		1658	1
		1659	}
		1660	};
		1661
		1662	=item json => $cb->($handle, $hash_or_arrayref)
		1663
		1664	Reads a JSON object or array, decodes it and passes it to the
		1665	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1666
		1667	If a C<json> object was passed to the constructor, then that will be used
		1668	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1669
		1670	This read type uses the incremental parser available with JSON version
		1671	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1672	dependency on your own: this module will load the JSON module, but
		1673	AnyEvent does not depend on it itself.
		1674
		1675	Since JSON texts are fully self-delimiting, the C<json> read and write
		1676	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1677	the C<json> write type description, above, for an actual example.
		1678
		1679	=cut
		1680
		1681	register_read_type json => sub {
		1682	my ($self, $cb) = @_;
		1683
		1684	my $json = $self->{json} ||= json_coder;
		1685
		1686	my $data;
		1687	my $rbuf = \$self->{rbuf};
		1688
		1689	sub {
		1690	my $ref = eval { $json->incr_parse ($_[0]{rbuf}) };
		1691
		1692	if ($ref) {
		1693	$_[0]{rbuf} = $json->incr_text;
		1694	$json->incr_text = "";
		1695	$cb->($_[0], $ref);
		1696
		1697	1
		1698	} elsif ($@) {
		1699	# error case
		1700	$json->incr_skip;
		1701
		1702	$_[0]{rbuf} = $json->incr_text;
		1703	$json->incr_text = "";
		1704
		1705	$_[0]->_error (Errno::EBADMSG);
		1706
		1707	()
		1708	} else {
		1709	$_[0]{rbuf} = "";
		1710
		1711	()
		1712	}
		1713	}
		1714	};
		1715
		1716	=item storable => $cb->($handle, $ref)
		1717
		1718	Deserialises a L<Storable> frozen representation as written by the
		1719	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1720	data).
		1721
		1722	Raises C<EBADMSG> error if the data could not be decoded.
		1723
		1724	=cut
		1725
		1726	register_read_type storable => sub {
		1727	my ($self, $cb) = @_;
		1728
		1729	require Storable unless $Storable::VERSION;
		1730
		1731	sub {
		1732	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1733	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1734	or return;
		1735
		1736	my $format = length pack "w", $len;
		1737
		1738	# bypass unshift if we already have the remaining chunk
		1739	if ($format + $len <= length $_[0]{rbuf}) {
		1740	my $data = substr $_[0]{rbuf}, $format, $len;
		1741	substr $_[0]{rbuf}, 0, $format + $len, "";
		1742
		1743	eval { $cb->($_[0], Storable::thaw ($data)); 1 }
		1744	or return $_[0]->_error (Errno::EBADMSG);
		1745	} else {
		1746	# remove prefix
		1747	substr $_[0]{rbuf}, 0, $format, "";
		1748
		1749	# read remaining chunk
		1750	$_[0]->unshift_read (chunk => $len, sub {
		1751	eval { $cb->($_[0], Storable::thaw ($_[1])); 1 }
		1752	or $_[0]->_error (Errno::EBADMSG);
		1753	});
		1754	}
		1755
		1756	1
		1757	}
		1758	};
		1759
		1760	=back
		1761
		1762	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
		1763
		1764	Instead of one of the predefined types, you can also specify the name
		1765	of a package. AnyEvent will try to load the package and then expects to
		1766	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1767	progressively tries to load the parent package until it either finds the
		1768	function (good) or runs out of packages (bad).
		1769
		1770	Whenever this type is used, C<push_read> will invoke the function with the
		1771	handle object, the original callback and the remaining arguments.
		1772
		1773	The function is supposed to return a callback (usually a closure) that
		1774	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1775	mentally treat the function as a "configurable read type to read callback"
		1776	converter.
		1777
		1778	It should invoke the original callback when it is done reading (remember
		1779	to pass C<$handle> as first argument as all other callbacks do that,
		1780	although there is no strict requirement on this).
		1781
		1782	For examples, see the source of this module (F<perldoc -m
		1783	AnyEvent::Handle>, search for C<register_read_type>)).
554		1784
555	=item $handle->stop_read	1785	=item $handle->stop_read
556		1786
557	=item $handle->start_read	1787	=item $handle->start_read
558		1788
559	In rare cases you actually do not want to read anything form the	1789	In rare cases you actually do not want to read anything from the
560	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1790	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
561	any queued callbacks will be executed then. To start readign again, call	1791	any queued callbacks will be executed then. To start reading again, call
562	C<start_read>.	1792	C<start_read>.
		1793
		1794	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1795	you change the C<on_read> callback or push/unshift a read callback, and it
		1796	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1797	there are any read requests in the queue.
		1798
		1799	In older versions of this module (<= 5.3), these methods had no effect,
		1800	as TLS does not support half-duplex connections. In current versions they
		1801	work as expected, as this behaviour is required to avoid certain resource
		1802	attacks, where the program would be forced to read (and buffer) arbitrary
		1803	amounts of data before being able to send some data. The drawback is that
		1804	some readings of the the SSL/TLS specifications basically require this
		1805	attack to be working, as SSL/TLS implementations might stall sending data
		1806	during a rehandshake.
		1807
		1808	As a guideline, during the initial handshake, you should not stop reading,
		1809	and as a client, it might cause problems, depending on your application.
563		1810
564	=cut	1811	=cut
565		1812
566	sub stop_read {	1813	sub stop_read {
567	my ($self) = @_;	1814	my ($self) = @_;
568		1815
569	delete $self->{rw};	1816	delete $self->{_rw};
570	}	1817	}
571		1818
572	sub start_read {	1819	sub start_read {
573	my ($self) = @_;	1820	my ($self) = @_;
574		1821
575	unless ($self->{rw} || $self->{eof}) {	1822	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
576	Scalar::Util::weaken $self;	1823	Scalar::Util::weaken $self;
577		1824
578	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1825	$self->{_rw} = AE::io $self->{fh}, 0, sub {
		1826	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
579	my $len = sysread $self->{fh}, $self->{rbuf}, $self->{read_size} || 8192, length $self->{rbuf};	1827	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
580		1828
581	if ($len > 0) {	1829	if ($len > 0) {
582	if (defined $self->{rbuf_max}) {	1830	$self->{_activity} = $self->{_ractivity} = AE::now;
583	if ($self->{rbuf_max} < length $self->{rbuf}) {	1831
584	$! = &Errno::ENOSPC; return $self->error;	1832	if ($self->{tls}) {
585	}	1833	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1834
		1835	&_dotls ($self);
		1836	} else {
		1837	$self->_drain_rbuf;
586	}	1838	}
587		1839
		1840	if ($len == $self->{read_size}) {
		1841	$self->{read_size} *= 2;
		1842	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		1843	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		1844	}
		1845
588	} elsif (defined $len) {	1846	} elsif (defined $len) {
589	$self->{eof} = 1;
590	delete $self->{rw};	1847	delete $self->{_rw};
		1848	$self->{_eof} = 1;
		1849	$self->_drain_rbuf;
591		1850
592	} elsif ($! != EAGAIN && $! != EINTR) {	1851	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
593	return $self->error;	1852	return $self->_error ($!, 1);
594	}	1853	}
		1854	};
		1855	}
		1856	}
595		1857
		1858	our $ERROR_SYSCALL;
		1859	our $ERROR_WANT_READ;
		1860
		1861	sub _tls_error {
		1862	my ($self, $err) = @_;
		1863
		1864	return $self->_error ($!, 1)
		1865	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1866
		1867	my $err = Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1868
		1869	# reduce error string to look less scary
		1870	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1871
		1872	if ($self->{_on_starttls}) {
		1873	(delete $self->{_on_starttls})->($self, undef, $err);
		1874	&_freetls;
		1875	} else {
		1876	&_freetls;
		1877	$self->_error (Errno::EPROTO, 1, $err);
		1878	}
		1879	}
		1880
		1881	# poll the write BIO and send the data if applicable
		1882	# also decode read data if possible
		1883	# this is basiclaly our TLS state machine
		1884	# more efficient implementations are possible with openssl,
		1885	# but not with the buggy and incomplete Net::SSLeay.
		1886	sub _dotls {
		1887	my ($self) = @_;
		1888
		1889	my $tmp;
		1890
		1891	if (length $self->{_tls_wbuf}) {
		1892	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
		1893	substr $self->{_tls_wbuf}, 0, $tmp, "";
		1894	}
		1895
		1896	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1897	return $self->_tls_error ($tmp)
		1898	if $tmp != $ERROR_WANT_READ
		1899	&& ($tmp != $ERROR_SYSCALL || $!);
		1900	}
		1901
		1902	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1903	unless (length $tmp) {
		1904	$self->{_on_starttls}
		1905	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1906	&_freetls;
		1907
		1908	if ($self->{on_stoptls}) {
		1909	$self->{on_stoptls}($self);
		1910	return;
		1911	} else {
		1912	# let's treat SSL-eof as we treat normal EOF
		1913	delete $self->{_rw};
		1914	$self->{_eof} = 1;
		1915	}
		1916	}
		1917
		1918	$self->{_tls_rbuf} .= $tmp;
596	$self->_drain_rbuf;	1919	$self->_drain_rbuf;
		1920	$self->{tls} or return; # tls session might have gone away in callback
		1921	}
		1922
		1923	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1924	return $self->_tls_error ($tmp)
		1925	if $tmp != $ERROR_WANT_READ
		1926	&& ($tmp != $ERROR_SYSCALL || $!);
		1927
		1928	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1929	$self->{wbuf} .= $tmp;
		1930	$self->_drain_wbuf;
		1931	$self->{tls} or return; # tls session might have gone away in callback
		1932	}
		1933
		1934	$self->{_on_starttls}
		1935	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
		1936	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
		1937	}
		1938
		1939	=item $handle->starttls ($tls[, $tls_ctx])
		1940
		1941	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1942	object is created, you can also do that at a later time by calling
		1943	C<starttls>. See the C<tls> constructor argument for general info.
		1944
		1945	Starting TLS is currently an asynchronous operation - when you push some
		1946	write data and then call C<< ->starttls >> then TLS negotiation will start
		1947	immediately, after which the queued write data is then sent. This might
		1948	change in future versions, so best make sure you have no outstanding write
		1949	data when calling this method.
		1950
		1951	The first argument is the same as the C<tls> constructor argument (either
		1952	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1953
		1954	The second argument is the optional C<AnyEvent::TLS> object that is used
		1955	when AnyEvent::Handle has to create its own TLS connection object, or
		1956	a hash reference with C<< key => value >> pairs that will be used to
		1957	construct a new context.
		1958
		1959	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1960	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1961	changed to your liking. Note that the handshake might have already started
		1962	when this function returns.
		1963
		1964	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1965	handshakes on the same stream. It is best to not attempt to use the
		1966	stream after stopping TLS.
		1967
		1968	This method may invoke callbacks (and therefore the handle might be
		1969	destroyed after it returns).
		1970
		1971	=cut
		1972
		1973	our %TLS_CACHE; #TODO not yet documented, should we?
		1974
		1975	sub starttls {
		1976	my ($self, $tls, $ctx) = @_;
		1977
		1978	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1979	if $self->{tls};
		1980
		1981	unless (defined $AnyEvent::TLS::VERSION) {
		1982	eval {
		1983	require Net::SSLeay;
		1984	require AnyEvent::TLS;
		1985	1
		1986	} or return $self->_error (Errno::EPROTO, 1, "TLS support not available on this system");
		1987	}
		1988
		1989	$self->{tls} = $tls;
		1990	$self->{tls_ctx} = $ctx if @_ > 2;
		1991
		1992	return unless $self->{fh};
		1993
		1994	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1995	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1996
		1997	$tls = delete $self->{tls};
		1998	$ctx = $self->{tls_ctx};
		1999
		2000	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		2001
		2002	if ("HASH" eq ref $ctx) {
		2003	if ($ctx->{cache}) {
		2004	my $key = $ctx+0;
		2005	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		2006	} else {
		2007	$ctx = new AnyEvent::TLS %$ctx;
		2008	}
		2009	}
		2010
		2011	$self->{tls_ctx} = $ctx || TLS_CTX ();
		2012	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
		2013
		2014	# basically, this is deep magic (because SSL_read should have the same issues)
		2015	# but the openssl maintainers basically said: "trust us, it just works".
		2016	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		2017	# and mismaintained ssleay-module doesn't even offer them).
		2018	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		2019	#
		2020	# in short: this is a mess.
		2021	#
		2022	# note that we do not try to keep the length constant between writes as we are required to do.
		2023	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		2024	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		2025	# have identity issues in that area.
		2026	# Net::SSLeay::CTX_set_mode ($ssl,
		2027	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		2028	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		2029	Net::SSLeay::CTX_set_mode ($tls, 1|2);
		2030
		2031	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		2032	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		2033
		2034	Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
		2035	$self->{rbuf} = "";
		2036
		2037	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
		2038
		2039	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
		2040	if $self->{on_starttls};
		2041
		2042	&_dotls; # need to trigger the initial handshake
		2043	$self->start_read; # make sure we actually do read
		2044	}
		2045
		2046	=item $handle->stoptls
		2047
		2048	Shuts down the SSL connection - this makes a proper EOF handshake by
		2049	sending a close notify to the other side, but since OpenSSL doesn't
		2050	support non-blocking shut downs, it is not guaranteed that you can re-use
		2051	the stream afterwards.
		2052
		2053	This method may invoke callbacks (and therefore the handle might be
		2054	destroyed after it returns).
		2055
		2056	=cut
		2057
		2058	sub stoptls {
		2059	my ($self) = @_;
		2060
		2061	if ($self->{tls} && $self->{fh}) {
		2062	Net::SSLeay::shutdown ($self->{tls});
		2063
		2064	&_dotls;
		2065
		2066	# # we don't give a shit. no, we do, but we can't. no...#d#
		2067	# # we, we... have to use openssl :/#d#
		2068	# &_freetls;#d#
		2069	}
		2070	}
		2071
		2072	sub _freetls {
		2073	my ($self) = @_;
		2074
		2075	return unless $self->{tls};
		2076
		2077	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2078	if $self->{tls} > 0;
		2079
		2080	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		2081	}
		2082
		2083	=item $handle->resettls
		2084
		2085	This rarely-used method simply resets and TLS state on the handle, usually
		2086	causing data loss.
		2087
		2088	One case where it may be useful is when you want to skip over the data in
		2089	the stream but you are not interested in interpreting it, so data loss is
		2090	no concern.
		2091
		2092	=cut
		2093
		2094	*resettls = \&_freetls;
		2095
		2096	sub DESTROY {
		2097	my ($self) = @_;
		2098
		2099	&_freetls;
		2100
		2101	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		2102
		2103	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2104	my $fh = delete $self->{fh};
		2105	my $wbuf = delete $self->{wbuf};
		2106
		2107	my @linger;
		2108
		2109	push @linger, AE::io $fh, 1, sub {
		2110	my $len = syswrite $fh, $wbuf, length $wbuf;
		2111
		2112	if ($len > 0) {
		2113	substr $wbuf, 0, $len, "";
		2114	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
		2115	@linger = (); # end
		2116	}
		2117	};
		2118	push @linger, AE::timer $linger, 0, sub {
		2119	@linger = ();
		2120	};
		2121	}
		2122	}
		2123
		2124	=item $handle->destroy
		2125
		2126	Shuts down the handle object as much as possible - this call ensures that
		2127	no further callbacks will be invoked and as many resources as possible
		2128	will be freed. Any method you will call on the handle object after
		2129	destroying it in this way will be silently ignored (and it will return the
		2130	empty list).
		2131
		2132	Normally, you can just "forget" any references to an AnyEvent::Handle
		2133	object and it will simply shut down. This works in fatal error and EOF
		2134	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2135	callback, so when you want to destroy the AnyEvent::Handle object from
		2136	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2137	that case.
		2138
		2139	Destroying the handle object in this way has the advantage that callbacks
		2140	will be removed as well, so if those are the only reference holders (as
		2141	is common), then one doesn't need to do anything special to break any
		2142	reference cycles.
		2143
		2144	The handle might still linger in the background and write out remaining
		2145	data, as specified by the C<linger> option, however.
		2146
		2147	=cut
		2148
		2149	sub destroy {
		2150	my ($self) = @_;
		2151
		2152	$self->DESTROY;
		2153	%$self = ();
		2154	bless $self, "AnyEvent::Handle::destroyed";
		2155	}
		2156
		2157	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2158	#nop
		2159	}
		2160
		2161	=item $handle->destroyed
		2162
		2163	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2164	->destroy >>, true otherwise.
		2165
		2166	Can be useful to decide whether the handle is still valid after some
		2167	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2168	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2169	can destroy the handle, so work can be avoided by checking sometimes:
		2170
		2171	$hdl->starttls ("accept");
		2172	return if $hdl->destroyed;
		2173	$hdl->push_write (...
		2174
		2175	Note that the call to C<push_write> will silently be ignored if the handle
		2176	has been destroyed, so often you can just ignore the possibility of the
		2177	handle being destroyed.
		2178
		2179	=cut
		2180
		2181	sub destroyed { 0 }
		2182	sub AnyEvent::Handle::destroyed::destroyed { 1 }
		2183
		2184	=item AnyEvent::Handle::TLS_CTX
		2185
		2186	This function creates and returns the AnyEvent::TLS object used by default
		2187	for TLS mode.
		2188
		2189	The context is created by calling L<AnyEvent::TLS> without any arguments.
		2190
		2191	=cut
		2192
		2193	our $TLS_CTX;
		2194
		2195	sub TLS_CTX() {
		2196	$TLS_CTX ||= do {
		2197	require AnyEvent::TLS;
		2198
		2199	new AnyEvent::TLS
		2200	}
		2201	}
		2202
		2203	=back
		2204
		2205
		2206	=head1 NONFREQUENTLY ASKED QUESTIONS
		2207
		2208	=over 4
		2209
		2210	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2211	still get further invocations!
		2212
		2213	That's because AnyEvent::Handle keeps a reference to itself when handling
		2214	read or write callbacks.
		2215
		2216	It is only safe to "forget" the reference inside EOF or error callbacks,
		2217	from within all other callbacks, you need to explicitly call the C<<
		2218	->destroy >> method.
		2219
		2220	=item Why is my C<on_eof> callback never called?
		2221
		2222	Probably because your C<on_error> callback is being called instead: When
		2223	you have outstanding requests in your read queue, then an EOF is
		2224	considered an error as you clearly expected some data.
		2225
		2226	To avoid this, make sure you have an empty read queue whenever your handle
		2227	is supposed to be "idle" (i.e. connection closes are O.K.). You can set
		2228	an C<on_read> handler that simply pushes the first read requests in the
		2229	queue.
		2230
		2231	See also the next question, which explains this in a bit more detail.
		2232
		2233	=item How can I serve requests in a loop?
		2234
		2235	Most protocols consist of some setup phase (authentication for example)
		2236	followed by a request handling phase, where the server waits for requests
		2237	and handles them, in a loop.
		2238
		2239	There are two important variants: The first (traditional, better) variant
		2240	handles requests until the server gets some QUIT command, causing it to
		2241	close the connection first (highly desirable for a busy TCP server). A
		2242	client dropping the connection is an error, which means this variant can
		2243	detect an unexpected detection close.
		2244
		2245	To handle this case, always make sure you have a on-empty read queue, by
		2246	pushing the "read request start" handler on it:
		2247
		2248	# we assume a request starts with a single line
		2249	my @start_request; @start_request = (line => sub {
		2250	my ($hdl, $line) = @_;
		2251
		2252	... handle request
		2253
		2254	# push next request read, possibly from a nested callback
		2255	$hdl->push_read (@start_request);
		2256	});
		2257
		2258	# auth done, now go into request handling loop
		2259	# now push the first @start_request
		2260	$hdl->push_read (@start_request);
		2261
		2262	By always having an outstanding C<push_read>, the handle always expects
		2263	some data and raises the C<EPIPE> error when the connction is dropped
		2264	unexpectedly.
		2265
		2266	The second variant is a protocol where the client can drop the connection
		2267	at any time. For TCP, this means that the server machine may run out of
		2268	sockets easier, and in general, it means you cannot distinguish a protocl
		2269	failure/client crash from a normal connection close. Nevertheless, these
		2270	kinds of protocols are common (and sometimes even the best solution to the
		2271	problem).
		2272
		2273	Having an outstanding read request at all times is possible if you ignore
		2274	C<EPIPE> errors, but this doesn't help with when the client drops the
		2275	connection during a request, which would still be an error.
		2276
		2277	A better solution is to push the initial request read in an C<on_read>
		2278	callback. This avoids an error, as when the server doesn't expect data
		2279	(i.e. is idly waiting for the next request, an EOF will not raise an
		2280	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2281	and simpler:
		2282
		2283	# auth done, now go into request handling loop
		2284	$hdl->on_read (sub {
		2285	my ($hdl) = @_;
		2286
		2287	# called each time we receive data but the read queue is empty
		2288	# simply start read the request
		2289
		2290	$hdl->push_read (line => sub {
		2291	my ($hdl, $line) = @_;
		2292
		2293	... handle request
		2294
		2295	# do nothing special when the request has been handled, just
		2296	# let the request queue go empty.
597	});	2297	});
		2298	});
		2299
		2300	=item I get different callback invocations in TLS mode/Why can't I pause
		2301	reading?
		2302
		2303	Unlike, say, TCP, TLS connections do not consist of two independent
		2304	communication channels, one for each direction. Or put differently, the
		2305	read and write directions are not independent of each other: you cannot
		2306	write data unless you are also prepared to read, and vice versa.
		2307
		2308	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2309	callback invocations when you are not expecting any read data - the reason
		2310	is that AnyEvent::Handle always reads in TLS mode.
		2311
		2312	During the connection, you have to make sure that you always have a
		2313	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2314	connection (or when you no longer want to use it) you can call the
		2315	C<destroy> method.
		2316
		2317	=item How do I read data until the other side closes the connection?
		2318
		2319	If you just want to read your data into a perl scalar, the easiest way
		2320	to achieve this is by setting an C<on_read> callback that does nothing,
		2321	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2322	will be in C<$_[0]{rbuf}>:
		2323
		2324	$handle->on_read (sub { });
		2325	$handle->on_eof (undef);
		2326	$handle->on_error (sub {
		2327	my $data = delete $_[0]{rbuf};
		2328	});
		2329
		2330	Note that this example removes the C<rbuf> member from the handle object,
		2331	which is not normally allowed by the API. It is expressly permitted in
		2332	this case only, as the handle object needs to be destroyed afterwards.
		2333
		2334	The reason to use C<on_error> is that TCP connections, due to latencies
		2335	and packets loss, might get closed quite violently with an error, when in
		2336	fact all data has been received.
		2337
		2338	It is usually better to use acknowledgements when transferring data,
		2339	to make sure the other side hasn't just died and you got the data
		2340	intact. This is also one reason why so many internet protocols have an
		2341	explicit QUIT command.
		2342
		2343	=item I don't want to destroy the handle too early - how do I wait until
		2344	all data has been written?
		2345
		2346	After writing your last bits of data, set the C<on_drain> callback
		2347	and destroy the handle in there - with the default setting of
		2348	C<low_water_mark> this will be called precisely when all data has been
		2349	written to the socket:
		2350
		2351	$handle->push_write (...);
		2352	$handle->on_drain (sub {
		2353	AE::log debug => "All data submitted to the kernel.";
		2354	undef $handle;
		2355	});
		2356
		2357	If you just want to queue some data and then signal EOF to the other side,
		2358	consider using C<< ->push_shutdown >> instead.
		2359
		2360	=item I want to contact a TLS/SSL server, I don't care about security.
		2361
		2362	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2363	connect to it and then create the AnyEvent::Handle with the C<tls>
		2364	parameter:
		2365
		2366	tcp_connect $host, $port, sub {
		2367	my ($fh) = @_;
		2368
		2369	my $handle = new AnyEvent::Handle
		2370	fh => $fh,
		2371	tls => "connect",
		2372	on_error => sub { ... };
		2373
		2374	$handle->push_write (...);
598	}	2375	};
599	}	2376
		2377	=item I want to contact a TLS/SSL server, I do care about security.
		2378
		2379	Then you should additionally enable certificate verification, including
		2380	peername verification, if the protocol you use supports it (see
		2381	L<AnyEvent::TLS>, C<verify_peername>).
		2382
		2383	E.g. for HTTPS:
		2384
		2385	tcp_connect $host, $port, sub {
		2386	my ($fh) = @_;
		2387
		2388	my $handle = new AnyEvent::Handle
		2389	fh => $fh,
		2390	peername => $host,
		2391	tls => "connect",
		2392	tls_ctx => { verify => 1, verify_peername => "https" },
		2393	...
		2394
		2395	Note that you must specify the hostname you connected to (or whatever
		2396	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2397	peername verification will be done.
		2398
		2399	The above will use the system-dependent default set of trusted CA
		2400	certificates. If you want to check against a specific CA, add the
		2401	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2402
		2403	tls_ctx => {
		2404	verify => 1,
		2405	verify_peername => "https",
		2406	ca_file => "my-ca-cert.pem",
		2407	},
		2408
		2409	=item I want to create a TLS/SSL server, how do I do that?
		2410
		2411	Well, you first need to get a server certificate and key. You have
		2412	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2413	self-signed certificate (cheap. check the search engine of your choice,
		2414	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2415	nice program for that purpose).
		2416
		2417	Then create a file with your private key (in PEM format, see
		2418	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2419	file should then look like this:
		2420
		2421	-----BEGIN RSA PRIVATE KEY-----
		2422	...header data
		2423	... lots of base64'y-stuff
		2424	-----END RSA PRIVATE KEY-----
		2425
		2426	-----BEGIN CERTIFICATE-----
		2427	... lots of base64'y-stuff
		2428	-----END CERTIFICATE-----
		2429
		2430	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2431	specify this file as C<cert_file>:
		2432
		2433	tcp_server undef, $port, sub {
		2434	my ($fh) = @_;
		2435
		2436	my $handle = new AnyEvent::Handle
		2437	fh => $fh,
		2438	tls => "accept",
		2439	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2440	...
		2441
		2442	When you have intermediate CA certificates that your clients might not
		2443	know about, just append them to the C<cert_file>.
600		2444
601	=back	2445	=back
602		2446
		2447	=head1 SUBCLASSING AnyEvent::Handle
		2448
		2449	In many cases, you might want to subclass AnyEvent::Handle.
		2450
		2451	To make this easier, a given version of AnyEvent::Handle uses these
		2452	conventions:
		2453
		2454	=over 4
		2455
		2456	=item * all constructor arguments become object members.
		2457
		2458	At least initially, when you pass a C<tls>-argument to the constructor it
		2459	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2460	mutated later on (for example C<tls> will hold the TLS connection object).
		2461
		2462	=item * other object member names are prefixed with an C<_>.
		2463
		2464	All object members not explicitly documented (internal use) are prefixed
		2465	with an underscore character, so the remaining non-C<_>-namespace is free
		2466	for use for subclasses.
		2467
		2468	=item * all members not documented here and not prefixed with an underscore
		2469	are free to use in subclasses.
		2470
		2471	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2472	member variables, but that's just life. At least it is documented.
		2473
		2474	=back
		2475
603	=head1 AUTHOR	2476	=head1 AUTHOR
604		2477
605	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	2478	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
606		2479
607	=cut	2480	=cut
608		2481
609	1; # End of AnyEvent::Handle	2482	1
		2483

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