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Revision 1.214 by root, Sun Jan 16 17:12:27 2011 UTC

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict;
5
6	use AnyEvent ();
7	use AnyEvent::Util qw(WSAWOULDBLOCK);
8	use Scalar::Util ();
9	use Carp ();
10	use Fcntl ();
11	use Errno qw/EAGAIN EINTR/;
12
13	=head1 NAME	1	=head1 NAME
14		2
15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent	3	AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
16
17	=cut
18
19	our $VERSION = '0.04';
20		4
21	=head1 SYNOPSIS	5	=head1 SYNOPSIS
22		6
23	use AnyEvent;	7	use AnyEvent;
24	use AnyEvent::Handle;	8	use AnyEvent::Handle;
25		9
26	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
27		11
28	my $handle =	12	my $hdl; $hdl = new AnyEvent::Handle
29	AnyEvent::Handle->new (
30	fh => \*STDIN,	13	fh => \*STDIN,
31	on_eof => sub {	14	on_error => sub {
32	$cv->broadcast;	15	my ($hdl, $fatal, $msg) = @_;
33	},	16	warn "got error $msg\n";
		17	$hdl->destroy;
		18	$cv->send;
34	);	19	};
35		20
36	# send some request line	21	# send some request line
37	$handle->push_write ("getinfo\015\012");	22	$hdl->push_write ("getinfo\015\012");
38		23
39	# read the response line	24	# read the response line
40	$handle->push_read (line => sub {	25	$hdl->push_read (line => sub {
41	my ($handle, $line) = @_;	26	my ($hdl, $line) = @_;
42	warn "read line <$line>\n";	27	warn "got line <$line>\n";
43	$cv->send;	28	$cv->send;
44	});	29	});
45		30
46	$cv->recv;	31	$cv->recv;
47		32
48	=head1 DESCRIPTION	33	=head1 DESCRIPTION
49		34
50	This module is a helper module to make it easier to do event-based I/O on	35	This is a helper module to make it easier to do event-based I/O on
51	filehandles. For utility functions for doing non-blocking connects and accepts	36	stream-based filehandles (sockets, pipes, and other stream things).
52	on sockets see L<AnyEvent::Util>.
53		37
		38	The L<AnyEvent::Intro> tutorial contains some well-documented
		39	AnyEvent::Handle examples.
		40
54	In the following, when the documentation refers to of "bytes" then this	41	In the following, where the documentation refers to "bytes", it means
55	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
56	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.
57		47
58	All callbacks will be invoked with the handle object as their first	48	All callbacks will be invoked with the handle object as their first
59	argument.	49	argument.
60		50
		51	=cut
		52
		53	package AnyEvent::Handle;
		54
		55	use Scalar::Util ();
		56	use List::Util ();
		57	use Carp ();
		58	use Errno qw(EAGAIN EINTR);
		59
		60	use AnyEvent (); BEGIN { AnyEvent::common_sense }
		61	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		62
		63	our $VERSION = $AnyEvent::VERSION;
		64
		65	sub _load_func($) {
		66	my $func = $_[0];
		67
		68	unless (defined &$func) {
		69	my $pkg = $func;
		70	do {
		71	$pkg =~ s/::[^:]+$//
		72	or return;
		73	eval "require $pkg";
		74	} until defined &$func;
		75	}
		76
		77	\&$func
		78	}
		79
		80	sub MAX_READ_SIZE() { 131072 }
		81
61	=head1 METHODS	82	=head1 METHODS
62		83
63	=over 4	84	=over 4
64		85
65	=item B<new (%args)>	86	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
66		87
67	The constructor supports these arguments (all as key => value pairs).	88	The constructor supports these arguments (all as C<< key => value >> pairs).
68		89
69	=over 4	90	=over 4
70		91
71	=item fh => $filehandle [MANDATORY]	92	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
72		93
73	The filehandle this L<AnyEvent::Handle> object will operate on.	94	The filehandle this L<AnyEvent::Handle> object will operate on.
74
75	NOTE: The filehandle will be set to non-blocking (using	95	NOTE: The filehandle will be set to non-blocking mode (using
76	AnyEvent::Util::fh_nonblocking).	96	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		97	that mode.
77		98
78	=item on_eof => $cb->($self)	99	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
79		100
80	Set the callback to be called on EOF.	101	Try to connect to the specified host and service (port), using
		102	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		103	default C<peername>.
81		104
82	While not mandatory, it is highly recommended to set an eof callback,	105	You have to specify either this parameter, or C<fh>, above.
83	otherwise you might end up with a closed socket while you are still
84	waiting for data.
85		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
86	=item on_error => $cb->($self)	116	=item on_prepare => $cb->($handle)
87		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, $retry->())
		129
		130	This callback is called when a connection has been successfully established.
		131
		132	The peer's numeric host and port (the socket peername) are passed as
		133	parameters, together with a retry callback.
		134
		135	If, for some reason, the handle is not acceptable, calling C<$retry>
		136	will continue with the next connection target (in case of multi-homed
		137	hosts or SRV records there can be multiple connection endpoints). At the
		138	time it is called the read and write queues, eof status, tls status and
		139	similar properties of the handle will have been reset.
		140
		141	In most cases, you should ignore the C<$retry> parameter.
		142
		143	=item on_connect_error => $cb->($handle, $message)
		144
		145	This callback is called when the connection could not be
		146	established. C<$!> will contain the relevant error code, and C<$message> a
		147	message describing it (usually the same as C<"$!">).
		148
		149	If this callback isn't specified, then C<on_error> will be called with a
		150	fatal error instead.
		151
		152	=back
		153
		154	=item on_error => $cb->($handle, $fatal, $message)
		155
88	This is the fatal error callback, that is called when, well, a fatal error	156	This is the error callback, which is called when, well, some error
89	occurs, such as not being able to resolve the hostname, failure to connect	157	occured, such as not being able to resolve the hostname, failure to
90	or a read error.	158	connect, or a read error.
91		159
92	The object will not be in a usable state when this callback has been	160	Some errors are fatal (which is indicated by C<$fatal> being true). On
93	called.	161	fatal errors the handle object will be destroyed (by a call to C<< ->
		162	destroy >>) after invoking the error callback (which means you are free to
		163	examine the handle object). Examples of fatal errors are an EOF condition
		164	with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
		165	cases where the other side can close the connection at will, it is
		166	often easiest to not report C<EPIPE> errors in this callback.
94		167
		168	AnyEvent::Handle tries to find an appropriate error code for you to check
		169	against, but in some cases (TLS errors), this does not work well. It is
		170	recommended to always output the C<$message> argument in human-readable
		171	error messages (it's usually the same as C<"$!">).
		172
		173	Non-fatal errors can be retried by returning, but it is recommended
		174	to simply ignore this parameter and instead abondon the handle object
		175	when this callback is invoked. Examples of non-fatal errors are timeouts
		176	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		177
95	On callback entrance, the value of C<$!> contains the operating system	178	On entry to the callback, the value of C<$!> contains the operating
96	error (or C<ENOSPC>, C<EPIPE> or C<EBADMSG>).	179	system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
97		180	C<EPROTO>).
98	The callback should throw an exception. If it returns, then
99	AnyEvent::Handle will C<croak> for you.
100		181
101	While not mandatory, it is I<highly> recommended to set this callback, as	182	While not mandatory, it is I<highly> recommended to set this callback, as
102	you will not be notified of errors otherwise. The default simply calls	183	you will not be notified of errors otherwise. The default just calls
103	die.	184	C<croak>.
104		185
105	=item on_read => $cb->($self)	186	=item on_read => $cb->($handle)
106		187
107	This sets the default read callback, which is called when data arrives	188	This sets the default read callback, which is called when data arrives
108	and no read request is in the queue.	189	and no read request is in the queue (unlike read queue callbacks, this
		190	callback will only be called when at least one octet of data is in the
		191	read buffer).
109		192
110	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	193	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
111	method or access the C<$self->{rbuf}> member directly.	194	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		195	must not enlarge or modify the read buffer, you can only remove data at
		196	the beginning from it.
112		197
		198	You can also call C<< ->push_read (...) >> or any other function that
		199	modifies the read queue. Or do both. Or ...
		200
113	When an EOF condition is detected then AnyEvent::Handle will first try to	201	When an EOF condition is detected, AnyEvent::Handle will first try to
114	feed all the remaining data to the queued callbacks and C<on_read> before	202	feed all the remaining data to the queued callbacks and C<on_read> before
115	calling the C<on_eof> callback. If no progress can be made, then a fatal	203	calling the C<on_eof> callback. If no progress can be made, then a fatal
116	error will be raised (with C<$!> set to C<EPIPE>).	204	error will be raised (with C<$!> set to C<EPIPE>).
117		205
		206	Note that, unlike requests in the read queue, an C<on_read> callback
		207	doesn't mean you I<require> some data: if there is an EOF and there
		208	are outstanding read requests then an error will be flagged. With an
		209	C<on_read> callback, the C<on_eof> callback will be invoked.
		210
		211	=item on_eof => $cb->($handle)
		212
		213	Set the callback to be called when an end-of-file condition is detected,
		214	i.e. in the case of a socket, when the other side has closed the
		215	connection cleanly, and there are no outstanding read requests in the
		216	queue (if there are read requests, then an EOF counts as an unexpected
		217	connection close and will be flagged as an error).
		218
		219	For sockets, this just means that the other side has stopped sending data,
		220	you can still try to write data, and, in fact, one can return from the EOF
		221	callback and continue writing data, as only the read part has been shut
		222	down.
		223
		224	If an EOF condition has been detected but no C<on_eof> callback has been
		225	set, then a fatal error will be raised with C<$!> set to <0>.
		226
118	=item on_drain => $cb->()	227	=item on_drain => $cb->($handle)
119		228
120	This sets the callback that is called when the write buffer becomes empty	229	This sets the callback that is called when the write buffer becomes empty
121	(or when the callback is set and the buffer is empty already).	230	(or immediately if the buffer is empty already).
122		231
123	To append to the write buffer, use the C<< ->push_write >> method.	232	To append to the write buffer, use the C<< ->push_write >> method.
		233
		234	This callback is useful when you don't want to put all of your write data
		235	into the queue at once, for example, when you want to write the contents
		236	of some file to the socket you might not want to read the whole file into
		237	memory and push it into the queue, but instead only read more data from
		238	the file when the write queue becomes empty.
		239
		240	=item timeout => $fractional_seconds
		241
		242	=item rtimeout => $fractional_seconds
		243
		244	=item wtimeout => $fractional_seconds
		245
		246	If non-zero, then these enables an "inactivity" timeout: whenever this
		247	many seconds pass without a successful read or write on the underlying
		248	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
		249	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		250	error will be raised).
		251
		252	There are three variants of the timeouts that work independently
		253	of each other, for both read and write, just read, and just write:
		254	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		255	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		256	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		257
		258	Note that timeout processing is active even when you do not have
		259	any outstanding read or write requests: If you plan to keep the connection
		260	idle then you should disable the timeout temporarily or ignore the timeout
		261	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		262	restart the timeout.
		263
		264	Zero (the default) disables this timeout.
		265
		266	=item on_timeout => $cb->($handle)
		267
		268	Called whenever the inactivity timeout passes. If you return from this
		269	callback, then the timeout will be reset as if some activity had happened,
		270	so this condition is not fatal in any way.
124		271
125	=item rbuf_max => <bytes>	272	=item rbuf_max => <bytes>
126		273
127	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	274	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
128	when the read buffer ever (strictly) exceeds this size. This is useful to	275	when the read buffer ever (strictly) exceeds this size. This is useful to
129	avoid denial-of-service attacks.	276	avoid some forms of denial-of-service attacks.
130		277
131	For example, a server accepting connections from untrusted sources should	278	For example, a server accepting connections from untrusted sources should
132	be configured to accept only so-and-so much data that it cannot act on	279	be configured to accept only so-and-so much data that it cannot act on
133	(for example, when expecting a line, an attacker could send an unlimited	280	(for example, when expecting a line, an attacker could send an unlimited
134	amount of data without a callback ever being called as long as the line	281	amount of data without a callback ever being called as long as the line
135	isn't finished).	282	isn't finished).
136		283
		284	=item wbuf_max => <bytes>
		285
		286	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		287	when the write buffer ever (strictly) exceeds this size. This is useful to
		288	avoid some forms of denial-of-service attacks.
		289
		290	Although the units of this parameter is bytes, this is the I<raw> number
		291	of bytes not yet accepted by the kernel. This can make a difference when
		292	you e.g. use TLS, as TLS typically makes your write data larger (but it
		293	can also make it smaller due to compression).
		294
		295	As an example of when this limit is useful, take a chat server that sends
		296	chat messages to a client. If the client does not read those in a timely
		297	manner then the send buffer in the server would grow unbounded.
		298
		299	=item autocork => <boolean>
		300
		301	When disabled (the default), C<push_write> will try to immediately
		302	write the data to the handle if possible. This avoids having to register
		303	a write watcher and wait for the next event loop iteration, but can
		304	be inefficient if you write multiple small chunks (on the wire, this
		305	disadvantage is usually avoided by your kernel's nagle algorithm, see
		306	C<no_delay>, but this option can save costly syscalls).
		307
		308	When enabled, writes will always be queued till the next event loop
		309	iteration. This is efficient when you do many small writes per iteration,
		310	but less efficient when you do a single write only per iteration (or when
		311	the write buffer often is full). It also increases write latency.
		312
		313	=item no_delay => <boolean>
		314
		315	When doing small writes on sockets, your operating system kernel might
		316	wait a bit for more data before actually sending it out. This is called
		317	the Nagle algorithm, and usually it is beneficial.
		318
		319	In some situations you want as low a delay as possible, which can be
		320	accomplishd by setting this option to a true value.
		321
		322	The default is your operating system's default behaviour (most likely
		323	enabled). This option explicitly enables or disables it, if possible.
		324
		325	=item keepalive => <boolean>
		326
		327	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		328	normally, TCP connections have no time-out once established, so TCP
		329	connections, once established, can stay alive forever even when the other
		330	side has long gone. TCP keepalives are a cheap way to take down long-lived
		331	TCP connections when the other side becomes unreachable. While the default
		332	is OS-dependent, TCP keepalives usually kick in after around two hours,
		333	and, if the other side doesn't reply, take down the TCP connection some 10
		334	to 15 minutes later.
		335
		336	It is harmless to specify this option for file handles that do not support
		337	keepalives, and enabling it on connections that are potentially long-lived
		338	is usually a good idea.
		339
		340	=item oobinline => <boolean>
		341
		342	BSD majorly fucked up the implementation of TCP urgent data. The result
		343	is that almost no OS implements TCP according to the specs, and every OS
		344	implements it slightly differently.
		345
		346	If you want to handle TCP urgent data, then setting this flag (the default
		347	is enabled) gives you the most portable way of getting urgent data, by
		348	putting it into the stream.
		349
		350	Since BSD emulation of OOB data on top of TCP's urgent data can have
		351	security implications, AnyEvent::Handle sets this flag automatically
		352	unless explicitly specified. Note that setting this flag after
		353	establishing a connection I<may> be a bit too late (data loss could
		354	already have occured on BSD systems), but at least it will protect you
		355	from most attacks.
		356
137	=item read_size => <bytes>	357	=item read_size => <bytes>
138		358
139	The default read block size (the amount of bytes this module will try to read	359	The initial read block size, the number of bytes this module will try to
140	on each [loop iteration). Default: C<4096>.	360	read during each loop iteration. Each handle object will consume at least
		361	this amount of memory for the read buffer as well, so when handling many
		362	connections requirements). See also C<max_read_size>. Default: C<2048>.
		363
		364	=item max_read_size => <bytes>
		365
		366	The maximum read buffer size used by the dynamic adjustment
		367	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		368	one go it will double C<read_size> up to the maximum given by this
		369	option. Default: C<131072> or C<read_size>, whichever is higher.
141		370
142	=item low_water_mark => <bytes>	371	=item low_water_mark => <bytes>
143		372
144	Sets the amount of bytes (default: C<0>) that make up an "empty" write	373	Sets the number of bytes (default: C<0>) that make up an "empty" write
145	buffer: If the write reaches this size or gets even samller it is	374	buffer: If the buffer reaches this size or gets even samller it is
146	considered empty.	375	considered empty.
147		376
		377	Sometimes it can be beneficial (for performance reasons) to add data to
		378	the write buffer before it is fully drained, but this is a rare case, as
		379	the operating system kernel usually buffers data as well, so the default
		380	is good in almost all cases.
		381
		382	=item linger => <seconds>
		383
		384	If this is non-zero (default: C<3600>), the destructor of the
		385	AnyEvent::Handle object will check whether there is still outstanding
		386	write data and will install a watcher that will write this data to the
		387	socket. No errors will be reported (this mostly matches how the operating
		388	system treats outstanding data at socket close time).
		389
		390	This will not work for partial TLS data that could not be encoded
		391	yet. This data will be lost. Calling the C<stoptls> method in time might
		392	help.
		393
		394	=item peername => $string
		395
		396	A string used to identify the remote site - usually the DNS hostname
		397	(I<not> IDN!) used to create the connection, rarely the IP address.
		398
		399	Apart from being useful in error messages, this string is also used in TLS
		400	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		401	verification will be skipped when C<peername> is not specified or is
		402	C<undef>.
		403
148	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	404	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
149		405
150	When this parameter is given, it enables TLS (SSL) mode, that means it	406	When this parameter is given, it enables TLS (SSL) mode, that means
151	will start making tls handshake and will transparently encrypt/decrypt	407	AnyEvent will start a TLS handshake as soon as the connection has been
152	data.	408	established and will transparently encrypt/decrypt data afterwards.
		409
		410	All TLS protocol errors will be signalled as C<EPROTO>, with an
		411	appropriate error message.
153		412
154	TLS mode requires Net::SSLeay to be installed (it will be loaded	413	TLS mode requires Net::SSLeay to be installed (it will be loaded
155	automatically when you try to create a TLS handle).	414	automatically when you try to create a TLS handle): this module doesn't
		415	have a dependency on that module, so if your module requires it, you have
		416	to add the dependency yourself.
156		417
157	For the TLS server side, use C<accept>, and for the TLS client side of a	418	Unlike TCP, TLS has a server and client side: for the TLS server side, use
158	connection, use C<connect> mode.	419	C<accept>, and for the TLS client side of a connection, use C<connect>
		420	mode.
159		421
160	You can also provide your own TLS connection object, but you have	422	You can also provide your own TLS connection object, but you have
161	to make sure that you call either C<Net::SSLeay::set_connect_state>	423	to make sure that you call either C<Net::SSLeay::set_connect_state>
162	or C<Net::SSLeay::set_accept_state> on it before you pass it to	424	or C<Net::SSLeay::set_accept_state> on it before you pass it to
163	AnyEvent::Handle.	425	AnyEvent::Handle. Also, this module will take ownership of this connection
		426	object.
164		427
		428	At some future point, AnyEvent::Handle might switch to another TLS
		429	implementation, then the option to use your own session object will go
		430	away.
		431
		432	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		433	passing in the wrong integer will lead to certain crash. This most often
		434	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		435	segmentation fault.
		436
165	See the C<starttls> method if you need to start TLs negotiation later.	437	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
166		438
167	=item tls_ctx => $ssl_ctx	439	=item tls_ctx => $anyevent_tls
168		440
169	Use the given Net::SSLeay::CTX object to create the new TLS connection	441	Use the given C<AnyEvent::TLS> object to create the new TLS connection
170	(unless a connection object was specified directly). If this parameter is	442	(unless a connection object was specified directly). If this
171	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	443	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		444	C<AnyEvent::Handle::TLS_CTX>.
172		445
173	=item filter_r => $cb	446	Instead of an object, you can also specify a hash reference with C<< key
		447	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		448	new TLS context object.
174		449
175	=item filter_w => $cb	450	=item on_starttls => $cb->($handle, $success[, $error_message])
176		451
177	These exist, but are undocumented at this time.	452	This callback will be invoked when the TLS/SSL handshake has finished. If
		453	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		454	(C<on_stoptls> will not be called in this case).
		455
		456	The session in C<< $handle->{tls} >> can still be examined in this
		457	callback, even when the handshake was not successful.
		458
		459	TLS handshake failures will not cause C<on_error> to be invoked when this
		460	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		461
		462	Without this callback, handshake failures lead to C<on_error> being
		463	called as usual.
		464
		465	Note that you cannot just call C<starttls> again in this callback. If you
		466	need to do that, start an zero-second timer instead whose callback can
		467	then call C<< ->starttls >> again.
		468
		469	=item on_stoptls => $cb->($handle)
		470
		471	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		472	set, then it will be invoked after freeing the TLS session. If it is not,
		473	then a TLS shutdown condition will be treated like a normal EOF condition
		474	on the handle.
		475
		476	The session in C<< $handle->{tls} >> can still be examined in this
		477	callback.
		478
		479	This callback will only be called on TLS shutdowns, not when the
		480	underlying handle signals EOF.
		481
		482	=item json => JSON or JSON::XS object
		483
		484	This is the json coder object used by the C<json> read and write types.
		485
		486	If you don't supply it, then AnyEvent::Handle will create and use a
		487	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		488	texts.
		489
		490	Note that you are responsible to depend on the JSON module if you want to
		491	use this functionality, as AnyEvent does not have a dependency itself.
178		492
179	=back	493	=back
180		494
181	=cut	495	=cut
182		496
183	sub new {	497	sub new {
184	my $class = shift;	498	my $class = shift;
185
186	my $self = bless { @_ }, $class;	499	my $self = bless { @_ }, $class;
187		500
188	$self->{fh} or Carp::croak "mandatory argument fh is missing";	501	if ($self->{fh}) {
		502	$self->_start;
		503	return unless $self->{fh}; # could be gone by now
		504
		505	} elsif ($self->{connect}) {
		506	require AnyEvent::Socket;
		507
		508	$self->{peername} = $self->{connect}[0]
		509	unless exists $self->{peername};
		510
		511	$self->{_skip_drain_rbuf} = 1;
		512
		513	{
		514	Scalar::Util::weaken (my $self = $self);
		515
		516	$self->{_connect} =
		517	AnyEvent::Socket::tcp_connect (
		518	$self->{connect}[0],
		519	$self->{connect}[1],
		520	sub {
		521	my ($fh, $host, $port, $retry) = @_;
		522
		523	delete $self->{_connect}; # no longer needed
		524
		525	if ($fh) {
		526	$self->{fh} = $fh;
		527
		528	delete $self->{_skip_drain_rbuf};
		529	$self->_start;
		530
		531	$self->{on_connect}
		532	and $self->{on_connect}($self, $host, $port, sub {
		533	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		534	$self->{_skip_drain_rbuf} = 1;
		535	&$retry;
		536	});
		537
		538	} else {
		539	if ($self->{on_connect_error}) {
		540	$self->{on_connect_error}($self, "$!");
		541	$self->destroy;
		542	} else {
		543	$self->_error ($!, 1);
		544	}
		545	}
		546	},
		547	sub {
		548	local $self->{fh} = $_[0];
		549
		550	$self->{on_prepare}
		551	? $self->{on_prepare}->($self)
		552	: ()
		553	}
		554	);
		555	}
		556
		557	} else {
		558	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		559	}
		560
		561	$self
		562	}
		563
		564	sub _start {
		565	my ($self) = @_;
		566
		567	# too many clueless people try to use udp and similar sockets
		568	# with AnyEvent::Handle, do them a favour.
		569	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		570	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		571	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
189		572
190	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	573	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
191		574
192	if ($self->{tls}) {	575	$self->{_activity} =
193	require Net::SSLeay;	576	$self->{_ractivity} =
		577	$self->{_wactivity} = AE::now;
		578
		579	$self->{read_size} ||= 2048;
		580	$self->{max_read_size} = $self->{read_size}
		581	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		582
		583	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		584	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		585	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		586
		587	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		588	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		589
		590	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		591
194	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	592	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
195	}	593	if $self->{tls};
196		594
197	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
198	$self->on_error (delete $self->{on_error}) if $self->{on_error};
199	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	595	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
200	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
201		596
202	$self->start_read;	597	$self->start_read
		598	if $self->{on_read} || @{ $self->{_queue} };
203		599
204	$self	600	$self->_drain_wbuf;
205	}	601	}
206		602
207	sub _shutdown {
208	my ($self) = @_;
209
210	delete $self->{_rw};
211	delete $self->{_ww};
212	delete $self->{fh};
213	}
214
215	sub error {	603	sub _error {
216	my ($self) = @_;	604	my ($self, $errno, $fatal, $message) = @_;
217		605
218	{	606	$! = $errno;
219	local $!;	607	$message ||= "$!";
220	$self->_shutdown;
221	}
222		608
223	$self->{on_error}($self)
224	if $self->{on_error};	609	if ($self->{on_error}) {
225		610	$self->{on_error}($self, $fatal, $message);
		611	$self->destroy if $fatal;
		612	} elsif ($self->{fh} || $self->{connect}) {
		613	$self->destroy;
226	Carp::croak "AnyEvent::Handle uncaught fatal error: $!";	614	Carp::croak "AnyEvent::Handle uncaught error: $message";
		615	}
227	}	616	}
228		617
229	=item $fh = $handle->fh	618	=item $fh = $handle->fh
230		619
231	This method returns the file handle of the L<AnyEvent::Handle> object.	620	This method returns the file handle used to create the L<AnyEvent::Handle> object.
232		621
233	=cut	622	=cut
234		623
235	sub fh { $_[0]{fh} }	624	sub fh { $_[0]{fh} }
236		625
…		…
252		641
253	sub on_eof {	642	sub on_eof {
254	$_[0]{on_eof} = $_[1];	643	$_[0]{on_eof} = $_[1];
255	}	644	}
256		645
		646	=item $handle->on_timeout ($cb)
		647
		648	=item $handle->on_rtimeout ($cb)
		649
		650	=item $handle->on_wtimeout ($cb)
		651
		652	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		653	callback, or disables the callback (but not the timeout) if C<$cb> =
		654	C<undef>. See the C<timeout> constructor argument and method.
		655
		656	=cut
		657
		658	# see below
		659
		660	=item $handle->autocork ($boolean)
		661
		662	Enables or disables the current autocork behaviour (see C<autocork>
		663	constructor argument). Changes will only take effect on the next write.
		664
		665	=cut
		666
		667	sub autocork {
		668	$_[0]{autocork} = $_[1];
		669	}
		670
		671	=item $handle->no_delay ($boolean)
		672
		673	Enables or disables the C<no_delay> setting (see constructor argument of
		674	the same name for details).
		675
		676	=cut
		677
		678	sub no_delay {
		679	$_[0]{no_delay} = $_[1];
		680
		681	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		682	if $_[0]{fh};
		683	}
		684
		685	=item $handle->keepalive ($boolean)
		686
		687	Enables or disables the C<keepalive> setting (see constructor argument of
		688	the same name for details).
		689
		690	=cut
		691
		692	sub keepalive {
		693	$_[0]{keepalive} = $_[1];
		694
		695	eval {
		696	local $SIG{__DIE__};
		697	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		698	if $_[0]{fh};
		699	};
		700	}
		701
		702	=item $handle->oobinline ($boolean)
		703
		704	Enables or disables the C<oobinline> setting (see constructor argument of
		705	the same name for details).
		706
		707	=cut
		708
		709	sub oobinline {
		710	$_[0]{oobinline} = $_[1];
		711
		712	eval {
		713	local $SIG{__DIE__};
		714	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		715	if $_[0]{fh};
		716	};
		717	}
		718
		719	=item $handle->keepalive ($boolean)
		720
		721	Enables or disables the C<keepalive> setting (see constructor argument of
		722	the same name for details).
		723
		724	=cut
		725
		726	sub keepalive {
		727	$_[0]{keepalive} = $_[1];
		728
		729	eval {
		730	local $SIG{__DIE__};
		731	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		732	if $_[0]{fh};
		733	};
		734	}
		735
		736	=item $handle->on_starttls ($cb)
		737
		738	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		739
		740	=cut
		741
		742	sub on_starttls {
		743	$_[0]{on_starttls} = $_[1];
		744	}
		745
		746	=item $handle->on_stoptls ($cb)
		747
		748	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		749
		750	=cut
		751
		752	sub on_stoptls {
		753	$_[0]{on_stoptls} = $_[1];
		754	}
		755
		756	=item $handle->rbuf_max ($max_octets)
		757
		758	Configures the C<rbuf_max> setting (C<undef> disables it).
		759
		760	=item $handle->wbuf_max ($max_octets)
		761
		762	Configures the C<wbuf_max> setting (C<undef> disables it).
		763
		764	=cut
		765
		766	sub rbuf_max {
		767	$_[0]{rbuf_max} = $_[1];
		768	}
		769
		770	sub rbuf_max {
		771	$_[0]{wbuf_max} = $_[1];
		772	}
		773
		774	#############################################################################
		775
		776	=item $handle->timeout ($seconds)
		777
		778	=item $handle->rtimeout ($seconds)
		779
		780	=item $handle->wtimeout ($seconds)
		781
		782	Configures (or disables) the inactivity timeout.
		783
		784	=item $handle->timeout_reset
		785
		786	=item $handle->rtimeout_reset
		787
		788	=item $handle->wtimeout_reset
		789
		790	Reset the activity timeout, as if data was received or sent.
		791
		792	These methods are cheap to call.
		793
		794	=cut
		795
		796	for my $dir ("", "r", "w") {
		797	my $timeout = "${dir}timeout";
		798	my $tw = "_${dir}tw";
		799	my $on_timeout = "on_${dir}timeout";
		800	my $activity = "_${dir}activity";
		801	my $cb;
		802
		803	*$on_timeout = sub {
		804	$_[0]{$on_timeout} = $_[1];
		805	};
		806
		807	*$timeout = sub {
		808	my ($self, $new_value) = @_;
		809
		810	$new_value >= 0
		811	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		812
		813	$self->{$timeout} = $new_value;
		814	delete $self->{$tw}; &$cb;
		815	};
		816
		817	*{"${dir}timeout_reset"} = sub {
		818	$_[0]{$activity} = AE::now;
		819	};
		820
		821	# main workhorse:
		822	# reset the timeout watcher, as neccessary
		823	# also check for time-outs
		824	$cb = sub {
		825	my ($self) = @_;
		826
		827	if ($self->{$timeout} && $self->{fh}) {
		828	my $NOW = AE::now;
		829
		830	# when would the timeout trigger?
		831	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		832
		833	# now or in the past already?
		834	if ($after <= 0) {
		835	$self->{$activity} = $NOW;
		836
		837	if ($self->{$on_timeout}) {
		838	$self->{$on_timeout}($self);
		839	} else {
		840	$self->_error (Errno::ETIMEDOUT);
		841	}
		842
		843	# callback could have changed timeout value, optimise
		844	return unless $self->{$timeout};
		845
		846	# calculate new after
		847	$after = $self->{$timeout};
		848	}
		849
		850	Scalar::Util::weaken $self;
		851	return unless $self; # ->error could have destroyed $self
		852
		853	$self->{$tw} ||= AE::timer $after, 0, sub {
		854	delete $self->{$tw};
		855	$cb->($self);
		856	};
		857	} else {
		858	delete $self->{$tw};
		859	}
		860	}
		861	}
		862
257	#############################################################################	863	#############################################################################
258		864
259	=back	865	=back
260		866
261	=head2 WRITE QUEUE	867	=head2 WRITE QUEUE
…		…
274	=item $handle->on_drain ($cb)	880	=item $handle->on_drain ($cb)
275		881
276	Sets the C<on_drain> callback or clears it (see the description of	882	Sets the C<on_drain> callback or clears it (see the description of
277	C<on_drain> in the constructor).	883	C<on_drain> in the constructor).
278		884
		885	This method may invoke callbacks (and therefore the handle might be
		886	destroyed after it returns).
		887
279	=cut	888	=cut
280		889
281	sub on_drain {	890	sub on_drain {
282	my ($self, $cb) = @_;	891	my ($self, $cb) = @_;
283		892
284	$self->{on_drain} = $cb;	893	$self->{on_drain} = $cb;
285		894
286	$cb->($self)	895	$cb->($self)
287	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	896	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
288	}	897	}
289		898
290	=item $handle->push_write ($data)	899	=item $handle->push_write ($data)
291		900
292	Queues the given scalar to be written. You can push as much data as you	901	Queues the given scalar to be written. You can push as much data as
293	want (only limited by the available memory), as C<AnyEvent::Handle>	902	you want (only limited by the available memory and C<wbuf_max>), as
294	buffers it independently of the kernel.	903	C<AnyEvent::Handle> buffers it independently of the kernel.
		904
		905	This method may invoke callbacks (and therefore the handle might be
		906	destroyed after it returns).
295		907
296	=cut	908	=cut
297		909
298	sub _drain_wbuf {	910	sub _drain_wbuf {
299	my ($self) = @_;	911	my ($self) = @_;
…		…
303	Scalar::Util::weaken $self;	915	Scalar::Util::weaken $self;
304		916
305	my $cb = sub {	917	my $cb = sub {
306	my $len = syswrite $self->{fh}, $self->{wbuf};	918	my $len = syswrite $self->{fh}, $self->{wbuf};
307		919
308	if ($len >= 0) {	920	if (defined $len) {
309	substr $self->{wbuf}, 0, $len, "";	921	substr $self->{wbuf}, 0, $len, "";
310		922
		923	$self->{_activity} = $self->{_wactivity} = AE::now;
		924
311	$self->{on_drain}($self)	925	$self->{on_drain}($self)
312	if $self->{low_water_mark} >= length $self->{wbuf}	926	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
313	&& $self->{on_drain};	927	&& $self->{on_drain};
314		928
315	delete $self->{_ww} unless length $self->{wbuf};	929	delete $self->{_ww} unless length $self->{wbuf};
316	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAWOULDBLOCK) {	930	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
317	$self->error;	931	$self->_error ($!, 1);
318	}	932	}
319	};	933	};
320		934
321	# try to write data immediately	935	# try to write data immediately
322	$cb->();	936	$cb->() unless $self->{autocork};
323		937
324	# if still data left in wbuf, we need to poll	938	# if still data left in wbuf, we need to poll
325	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)	939	$self->{_ww} = AE::io $self->{fh}, 1, $cb
326	if length $self->{wbuf};	940	if length $self->{wbuf};
		941
		942	if (
		943	defined $self->{wbuf_max}
		944	&& $self->{wbuf_max} < length $self->{wbuf}
		945	) {
		946	$self->_error (Errno::ENOSPC, 1), return;
		947	}
327	};	948	};
328	}	949	}
329		950
330	our %WH;	951	our %WH;
331		952
		953	# deprecated
332	sub register_write_type($$) {	954	sub register_write_type($$) {
333	$WH{$_[0]} = $_[1];	955	$WH{$_[0]} = $_[1];
334	}	956	}
335		957
336	sub push_write {	958	sub push_write {
337	my $self = shift;	959	my $self = shift;
338		960
339	if (@_ > 1) {	961	if (@_ > 1) {
340	my $type = shift;	962	my $type = shift;
341		963
		964	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
342	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	965	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
343	->($self, @_);	966	->($self, @_);
344	}	967	}
345		968
		969	# we downgrade here to avoid hard-to-track-down bugs,
		970	# and diagnose the problem earlier and better.
		971
346	if ($self->{filter_w}) {	972	if ($self->{tls}) {
347	$self->{filter_w}->($self, \$_[0]);	973	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		974	&_dotls ($self) if $self->{fh};
348	} else {	975	} else {
349	$self->{wbuf} .= $_[0];	976	utf8::downgrade $self->{wbuf} .= $_[0];
350	$self->_drain_wbuf;	977	$self->_drain_wbuf if $self->{fh};
351	}	978	}
352	}	979	}
353		980
354	=item $handle->push_write (type => @args)	981	=item $handle->push_write (type => @args)
355		982
356	=item $handle->unshift_write (type => @args)
357
358	Instead of formatting your data yourself, you can also let this module do	983	Instead of formatting your data yourself, you can also let this module
359	the job by specifying a type and type-specific arguments.	984	do the job by specifying a type and type-specific arguments. You
		985	can also specify the (fully qualified) name of a package, in which
		986	case AnyEvent tries to load the package and then expects to find the
		987	C<anyevent_write_type> function inside (see "custom write types", below).
360		988
361	Predefined types are (if you have ideas for additional types, feel free to	989	Predefined types are (if you have ideas for additional types, feel free to
362	drop by and tell us):	990	drop by and tell us):
363		991
364	=over 4	992	=over 4
…		…
366	=item netstring => $string	994	=item netstring => $string
367		995
368	Formats the given value as netstring	996	Formats the given value as netstring
369	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).	997	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
370		998
371	=back
372
373	=cut	999	=cut
374		1000
375	register_write_type netstring => sub {	1001	register_write_type netstring => sub {
376	my ($self, $string) = @_;	1002	my ($self, $string) = @_;
377		1003
378	sprintf "%d:%s,", (length $string), $string	1004	(length $string) . ":$string,"
379	};	1005	};
380		1006
		1007	=item packstring => $format, $data
		1008
		1009	An octet string prefixed with an encoded length. The encoding C<$format>
		1010	uses the same format as a Perl C<pack> format, but must specify a single
		1011	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1012	optional C<!>, C<< < >> or C<< > >> modifier).
		1013
		1014	=cut
		1015
		1016	register_write_type packstring => sub {
		1017	my ($self, $format, $string) = @_;
		1018
		1019	pack "$format/a*", $string
		1020	};
		1021
381	=item json => $array_or_hashref	1022	=item json => $array_or_hashref
382		1023
383	=item AnyEvent::Handle::register_write_type type => $coderef->($self, @args)	1024	Encodes the given hash or array reference into a JSON object. Unless you
		1025	provide your own JSON object, this means it will be encoded to JSON text
		1026	in UTF-8.
384		1027
385	This function (not method) lets you add your own types to C<push_write>.	1028	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		1029	one end of a handle and read them at the other end without using any
		1030	additional framing.
		1031
		1032	The generated JSON text is guaranteed not to contain any newlines: While
		1033	this module doesn't need delimiters after or between JSON texts to be
		1034	able to read them, many other languages depend on that.
		1035
		1036	A simple RPC protocol that interoperates easily with others is to send
		1037	JSON arrays (or objects, although arrays are usually the better choice as
		1038	they mimic how function argument passing works) and a newline after each
		1039	JSON text:
		1040
		1041	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		1042	$handle->push_write ("\012");
		1043
		1044	An AnyEvent::Handle receiver would simply use the C<json> read type and
		1045	rely on the fact that the newline will be skipped as leading whitespace:
		1046
		1047	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1048
		1049	Other languages could read single lines terminated by a newline and pass
		1050	this line into their JSON decoder of choice.
		1051
		1052	=cut
		1053
		1054	sub json_coder() {
		1055	eval { require JSON::XS; JSON::XS->new->utf8 }
		1056	|| do { require JSON; JSON->new->utf8 }
		1057	}
		1058
		1059	register_write_type json => sub {
		1060	my ($self, $ref) = @_;
		1061
		1062	my $json = $self->{json} ||= json_coder;
		1063
		1064	$json->encode ($ref)
		1065	};
		1066
		1067	=item storable => $reference
		1068
		1069	Freezes the given reference using L<Storable> and writes it to the
		1070	handle. Uses the C<nfreeze> format.
		1071
		1072	=cut
		1073
		1074	register_write_type storable => sub {
		1075	my ($self, $ref) = @_;
		1076
		1077	require Storable;
		1078
		1079	pack "w/a*", Storable::nfreeze ($ref)
		1080	};
		1081
		1082	=back
		1083
		1084	=item $handle->push_shutdown
		1085
		1086	Sometimes you know you want to close the socket after writing your data
		1087	before it was actually written. One way to do that is to replace your
		1088	C<on_drain> handler by a callback that shuts down the socket (and set
		1089	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1090	replaces the C<on_drain> callback with:
		1091
		1092	sub { shutdown $_[0]{fh}, 1 }
		1093
		1094	This simply shuts down the write side and signals an EOF condition to the
		1095	the peer.
		1096
		1097	You can rely on the normal read queue and C<on_eof> handling
		1098	afterwards. This is the cleanest way to close a connection.
		1099
		1100	This method may invoke callbacks (and therefore the handle might be
		1101	destroyed after it returns).
		1102
		1103	=cut
		1104
		1105	sub push_shutdown {
		1106	my ($self) = @_;
		1107
		1108	delete $self->{low_water_mark};
		1109	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1110	}
		1111
		1112	=item custom write types - Package::anyevent_write_type $handle, @args
		1113
		1114	Instead of one of the predefined types, you can also specify the name of
		1115	a package. AnyEvent will try to load the package and then expects to find
		1116	a function named C<anyevent_write_type> inside. If it isn't found, it
		1117	progressively tries to load the parent package until it either finds the
		1118	function (good) or runs out of packages (bad).
		1119
386	Whenever the given C<type> is used, C<push_write> will invoke the code	1120	Whenever the given C<type> is used, C<push_write> will the function with
387	reference with the handle object and the remaining arguments.	1121	the handle object and the remaining arguments.
388		1122
389	The code reference is supposed to return a single octet string that will	1123	The function is supposed to return a single octet string that will be
390	be appended to the write buffer.	1124	appended to the write buffer, so you cna mentally treat this function as a
		1125	"arguments to on-the-wire-format" converter.
391		1126
392	Note that this is a function, and all types registered this way will be	1127	Example: implement a custom write type C<join> that joins the remaining
393	global, so try to use unique names.	1128	arguments using the first one.
		1129
		1130	$handle->push_write (My::Type => " ", 1,2,3);
		1131
		1132	# uses the following package, which can be defined in the "My::Type" or in
		1133	# the "My" modules to be auto-loaded, or just about anywhere when the
		1134	# My::Type::anyevent_write_type is defined before invoking it.
		1135
		1136	package My::Type;
		1137
		1138	sub anyevent_write_type {
		1139	my ($handle, $delim, @args) = @_;
		1140
		1141	join $delim, @args
		1142	}
394		1143
395	=cut	1144	=cut
396		1145
397	#############################################################################	1146	#############################################################################
398		1147
…		…
407	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1156	ways, the "simple" way, using only C<on_read> and the "complex" way, using
408	a queue.	1157	a queue.
409		1158
410	In the simple case, you just install an C<on_read> callback and whenever	1159	In the simple case, you just install an C<on_read> callback and whenever
411	new data arrives, it will be called. You can then remove some data (if	1160	new data arrives, it will be called. You can then remove some data (if
412	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1161	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
413	or not.	1162	leave the data there if you want to accumulate more (e.g. when only a
		1163	partial message has been received so far), or change the read queue with
		1164	e.g. C<push_read>.
414		1165
415	In the more complex case, you want to queue multiple callbacks. In this	1166	In the more complex case, you want to queue multiple callbacks. In this
416	case, AnyEvent::Handle will call the first queued callback each time new	1167	case, AnyEvent::Handle will call the first queued callback each time new
417	data arrives and removes it when it has done its job (see C<push_read>,	1168	data arrives (also the first time it is queued) and remove it when it has
418	below).	1169	done its job (see C<push_read>, below).
419		1170
420	This way you can, for example, push three line-reads, followed by reading	1171	This way you can, for example, push three line-reads, followed by reading
421	a chunk of data, and AnyEvent::Handle will execute them in order.	1172	a chunk of data, and AnyEvent::Handle will execute them in order.
422		1173
423	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1174	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
424	the specified number of bytes which give an XML datagram.	1175	the specified number of bytes which give an XML datagram.
425		1176
426	# in the default state, expect some header bytes	1177	# in the default state, expect some header bytes
427	$handle->on_read (sub {	1178	$handle->on_read (sub {
428	# some data is here, now queue the length-header-read (4 octets)	1179	# some data is here, now queue the length-header-read (4 octets)
429	shift->unshift_read_chunk (4, sub {	1180	shift->unshift_read (chunk => 4, sub {
430	# header arrived, decode	1181	# header arrived, decode
431	my $len = unpack "N", $_[1];	1182	my $len = unpack "N", $_[1];
432		1183
433	# now read the payload	1184	# now read the payload
434	shift->unshift_read_chunk ($len, sub {	1185	shift->unshift_read (chunk => $len, sub {
435	my $xml = $_[1];	1186	my $xml = $_[1];
436	# handle xml	1187	# handle xml
437	});	1188	});
438	});	1189	});
439	});	1190	});
440		1191
441	Example 2: Implement a client for a protocol that replies either with	1192	Example 2: Implement a client for a protocol that replies either with "OK"
442	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1193	and another line or "ERROR" for the first request that is sent, and 64
443	second request. Due tot he availability of a full queue, we can just	1194	bytes for the second request. Due to the availability of a queue, we can
444	pipeline sending both requests and manipulate the queue as necessary in	1195	just pipeline sending both requests and manipulate the queue as necessary
445	the callbacks:	1196	in the callbacks.
446		1197
447	# request one	1198	When the first callback is called and sees an "OK" response, it will
		1199	C<unshift> another line-read. This line-read will be queued I<before> the
		1200	64-byte chunk callback.
		1201
		1202	# request one, returns either "OK + extra line" or "ERROR"
448	$handle->push_write ("request 1\015\012");	1203	$handle->push_write ("request 1\015\012");
449		1204
450	# we expect "ERROR" or "OK" as response, so push a line read	1205	# we expect "ERROR" or "OK" as response, so push a line read
451	$handle->push_read_line (sub {	1206	$handle->push_read (line => sub {
452	# if we got an "OK", we have to _prepend_ another line,	1207	# if we got an "OK", we have to _prepend_ another line,
453	# so it will be read before the second request reads its 64 bytes	1208	# so it will be read before the second request reads its 64 bytes
454	# which are already in the queue when this callback is called	1209	# which are already in the queue when this callback is called
455	# we don't do this in case we got an error	1210	# we don't do this in case we got an error
456	if ($_[1] eq "OK") {	1211	if ($_[1] eq "OK") {
457	$_[0]->unshift_read_line (sub {	1212	$_[0]->unshift_read (line => sub {
458	my $response = $_[1];	1213	my $response = $_[1];
459	...	1214	...
460	});	1215	});
461	}	1216	}
462	});	1217	});
463		1218
464	# request two	1219	# request two, simply returns 64 octets
465	$handle->push_write ("request 2\015\012");	1220	$handle->push_write ("request 2\015\012");
466		1221
467	# simply read 64 bytes, always	1222	# simply read 64 bytes, always
468	$handle->push_read_chunk (64, sub {	1223	$handle->push_read (chunk => 64, sub {
469	my $response = $_[1];	1224	my $response = $_[1];
470	...	1225	...
471	});	1226	});
472		1227
473	=over 4	1228	=over 4
474		1229
475	=cut	1230	=cut
476		1231
477	sub _drain_rbuf {	1232	sub _drain_rbuf {
478	my ($self) = @_;	1233	my ($self) = @_;
		1234
		1235	# avoid recursion
		1236	return if $self->{_skip_drain_rbuf};
		1237	local $self->{_skip_drain_rbuf} = 1;
		1238
		1239	while () {
		1240	# we need to use a separate tls read buffer, as we must not receive data while
		1241	# we are draining the buffer, and this can only happen with TLS.
		1242	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1243	if exists $self->{_tls_rbuf};
		1244
		1245	my $len = length $self->{rbuf};
		1246
		1247	if (my $cb = shift @{ $self->{_queue} }) {
		1248	unless ($cb->($self)) {
		1249	# no progress can be made
		1250	# (not enough data and no data forthcoming)
		1251	$self->_error (Errno::EPIPE, 1), return
		1252	if $self->{_eof};
		1253
		1254	unshift @{ $self->{_queue} }, $cb;
		1255	last;
		1256	}
		1257	} elsif ($self->{on_read}) {
		1258	last unless $len;
		1259
		1260	$self->{on_read}($self);
		1261
		1262	if (
		1263	$len == length $self->{rbuf} # if no data has been consumed
		1264	&& !@{ $self->{_queue} } # and the queue is still empty
		1265	&& $self->{on_read} # but we still have on_read
		1266	) {
		1267	# no further data will arrive
		1268	# so no progress can be made
		1269	$self->_error (Errno::EPIPE, 1), return
		1270	if $self->{_eof};
		1271
		1272	last; # more data might arrive
		1273	}
		1274	} else {
		1275	# read side becomes idle
		1276	delete $self->{_rw} unless $self->{tls};
		1277	last;
		1278	}
		1279	}
		1280
		1281	if ($self->{_eof}) {
		1282	$self->{on_eof}
		1283	? $self->{on_eof}($self)
		1284	: $self->_error (0, 1, "Unexpected end-of-file");
		1285
		1286	return;
		1287	}
479		1288
480	if (	1289	if (
481	defined $self->{rbuf_max}	1290	defined $self->{rbuf_max}
482	&& $self->{rbuf_max} < length $self->{rbuf}	1291	&& $self->{rbuf_max} < length $self->{rbuf}
483	) {	1292	) {
484	$! = &Errno::ENOSPC;	1293	$self->_error (Errno::ENOSPC, 1), return;
485	$self->error;
486	}	1294	}
487		1295
488	return if $self->{in_drain};	1296	# may need to restart read watcher
489	local $self->{in_drain} = 1;	1297	unless ($self->{_rw}) {
490		1298	$self->start_read
491	while (my $len = length $self->{rbuf}) {	1299	if $self->{on_read} || @{ $self->{_queue} };
492	no strict 'refs';
493	if (my $cb = shift @{ $self->{_queue} }) {
494	unless ($cb->($self)) {
495	if ($self->{_eof}) {
496	# no progress can be made (not enough data and no data forthcoming)
497	$! = &Errno::EPIPE;
498	$self->error;
499	}
500
501	unshift @{ $self->{_queue} }, $cb;
502	return;
503	}
504	} elsif ($self->{on_read}) {
505	$self->{on_read}($self);
506
507	if (
508	$self->{_eof} # if no further data will arrive
509	&& $len == length $self->{rbuf} # and no data has been consumed
510	&& !@{ $self->{_queue} } # and the queue is still empty
511	&& $self->{on_read} # and we still want to read data
512	) {
513	# then no progress can be made
514	$! = &Errno::EPIPE;
515	$self->error;
516	}
517	} else {
518	# read side becomes idle
519	delete $self->{_rw};
520	return;
521	}
522	}
523
524	if ($self->{_eof}) {
525	$self->_shutdown;
526	$self->{on_eof}($self)
527	if $self->{on_eof};
528	}	1300	}
529	}	1301	}
530		1302
531	=item $handle->on_read ($cb)	1303	=item $handle->on_read ($cb)
532		1304
533	This replaces the currently set C<on_read> callback, or clears it (when	1305	This replaces the currently set C<on_read> callback, or clears it (when
534	the new callback is C<undef>). See the description of C<on_read> in the	1306	the new callback is C<undef>). See the description of C<on_read> in the
535	constructor.	1307	constructor.
536		1308
		1309	This method may invoke callbacks (and therefore the handle might be
		1310	destroyed after it returns).
		1311
537	=cut	1312	=cut
538		1313
539	sub on_read {	1314	sub on_read {
540	my ($self, $cb) = @_;	1315	my ($self, $cb) = @_;
541		1316
542	$self->{on_read} = $cb;	1317	$self->{on_read} = $cb;
		1318	$self->_drain_rbuf if $cb;
543	}	1319	}
544		1320
545	=item $handle->rbuf	1321	=item $handle->rbuf
546		1322
547	Returns the read buffer (as a modifiable lvalue).	1323	Returns the read buffer (as a modifiable lvalue). You can also access the
		1324	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1325	much faster, and no less clean).
548		1326
549	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1327	The only operation allowed on the read buffer (apart from looking at it)
550	you want.	1328	is removing data from its beginning. Otherwise modifying or appending to
		1329	it is not allowed and will lead to hard-to-track-down bugs.
551		1330
552	NOTE: The read buffer should only be used or modified if the C<on_read>,	1331	NOTE: The read buffer should only be used or modified in the C<on_read>
553	C<push_read> or C<unshift_read> methods are used. The other read methods	1332	callback or when C<push_read> or C<unshift_read> are used with a single
554	automatically manage the read buffer.	1333	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1334	will manage the read buffer on their own.
555		1335
556	=cut	1336	=cut
557		1337
558	sub rbuf : lvalue {	1338	sub rbuf : lvalue {
559	$_[0]{rbuf}	1339	$_[0]{rbuf}
…		…
576		1356
577	If enough data was available, then the callback must remove all data it is	1357	If enough data was available, then the callback must remove all data it is
578	interested in (which can be none at all) and return a true value. After returning	1358	interested in (which can be none at all) and return a true value. After returning
579	true, it will be removed from the queue.	1359	true, it will be removed from the queue.
580		1360
		1361	These methods may invoke callbacks (and therefore the handle might be
		1362	destroyed after it returns).
		1363
581	=cut	1364	=cut
582		1365
583	our %RH;	1366	our %RH;
584		1367
585	sub register_read_type($$) {	1368	sub register_read_type($$) {
…		…
591	my $cb = pop;	1374	my $cb = pop;
592		1375
593	if (@_) {	1376	if (@_) {
594	my $type = shift;	1377	my $type = shift;
595		1378
		1379	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
596	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	1380	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
597	->($self, $cb, @_);	1381	->($self, $cb, @_);
598	}	1382	}
599		1383
600	push @{ $self->{_queue} }, $cb;	1384	push @{ $self->{_queue} }, $cb;
601	$self->_drain_rbuf;	1385	$self->_drain_rbuf;
…		…
606	my $cb = pop;	1390	my $cb = pop;
607		1391
608	if (@_) {	1392	if (@_) {
609	my $type = shift;	1393	my $type = shift;
610		1394
		1395	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
611	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")	1396	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
612	->($self, $cb, @_);	1397	->($self, $cb, @_);
613	}	1398	}
614
615		1399
616	unshift @{ $self->{_queue} }, $cb;	1400	unshift @{ $self->{_queue} }, $cb;
617	$self->_drain_rbuf;	1401	$self->_drain_rbuf;
618	}	1402	}
619		1403
…		…
621		1405
622	=item $handle->unshift_read (type => @args, $cb)	1406	=item $handle->unshift_read (type => @args, $cb)
623		1407
624	Instead of providing a callback that parses the data itself you can chose	1408	Instead of providing a callback that parses the data itself you can chose
625	between a number of predefined parsing formats, for chunks of data, lines	1409	between a number of predefined parsing formats, for chunks of data, lines
626	etc.	1410	etc. You can also specify the (fully qualified) name of a package, in
		1411	which case AnyEvent tries to load the package and then expects to find the
		1412	C<anyevent_read_type> function inside (see "custom read types", below).
627		1413
628	Predefined types are (if you have ideas for additional types, feel free to	1414	Predefined types are (if you have ideas for additional types, feel free to
629	drop by and tell us):	1415	drop by and tell us):
630		1416
631	=over 4	1417	=over 4
632		1418
633	=item chunk => $octets, $cb->($self, $data)	1419	=item chunk => $octets, $cb->($handle, $data)
634		1420
635	Invoke the callback only once C<$octets> bytes have been read. Pass the	1421	Invoke the callback only once C<$octets> bytes have been read. Pass the
636	data read to the callback. The callback will never be called with less	1422	data read to the callback. The callback will never be called with less
637	data.	1423	data.
638		1424
…		…
652	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1438	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
653	1	1439	1
654	}	1440	}
655	};	1441	};
656		1442
657	# compatibility with older API
658	sub push_read_chunk {
659	$_[0]->push_read (chunk => $_[1], $_[2]);
660	}
661
662	sub unshift_read_chunk {
663	$_[0]->unshift_read (chunk => $_[1], $_[2]);
664	}
665
666	=item line => [$eol, ]$cb->($self, $line, $eol)	1443	=item line => [$eol, ]$cb->($handle, $line, $eol)
667		1444
668	The callback will be called only once a full line (including the end of	1445	The callback will be called only once a full line (including the end of
669	line marker, C<$eol>) has been read. This line (excluding the end of line	1446	line marker, C<$eol>) has been read. This line (excluding the end of line
670	marker) will be passed to the callback as second argument (C<$line>), and	1447	marker) will be passed to the callback as second argument (C<$line>), and
671	the end of line marker as the third argument (C<$eol>).	1448	the end of line marker as the third argument (C<$eol>).
…		…
685	=cut	1462	=cut
686		1463
687	register_read_type line => sub {	1464	register_read_type line => sub {
688	my ($self, $cb, $eol) = @_;	1465	my ($self, $cb, $eol) = @_;
689		1466
690	$eol = qr|(\015?\012)| if @_ < 3;	1467	if (@_ < 3) {
		1468	# this is more than twice as fast as the generic code below
		1469	sub {
		1470	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1471
		1472	$cb->($_[0], $1, $2);
		1473	1
		1474	}
		1475	} else {
691	$eol = quotemeta $eol unless ref $eol;	1476	$eol = quotemeta $eol unless ref $eol;
692	$eol = qr|^(.*?)($eol)|s;	1477	$eol = qr|^(.*?)($eol)|s;
693		1478
694	sub {	1479	sub {
695	$_[0]{rbuf} =~ s/$eol// or return;	1480	$_[0]{rbuf} =~ s/$eol// or return;
696		1481
697	$cb->($_[0], $1, $2);	1482	$cb->($_[0], $1, $2);
		1483	1
698	1	1484	}
699	}	1485	}
700	};	1486	};
701		1487
702	# compatibility with older API
703	sub push_read_line {
704	my $self = shift;
705	$self->push_read (line => @_);
706	}
707
708	sub unshift_read_line {
709	my $self = shift;
710	$self->unshift_read (line => @_);
711	}
712
713	=item netstring => $cb->($string)
714
715	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
716
717	Throws an error with C<$!> set to EBADMSG on format violations.
718
719	=cut
720
721	register_read_type netstring => sub {
722	my ($self, $cb) = @_;
723
724	sub {
725	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
726	if ($_[0]{rbuf} =~ /[^0-9]/) {
727	$! = &Errno::EBADMSG;
728	$self->error;
729	}
730	return;
731	}
732
733	my $len = $1;
734
735	$self->unshift_read (chunk => $len, sub {
736	my $string = $_[1];
737	$_[0]->unshift_read (chunk => 1, sub {
738	if ($_[1] eq ",") {
739	$cb->($_[0], $string);
740	} else {
741	$! = &Errno::EBADMSG;
742	$self->error;
743	}
744	});
745	});
746
747	1
748	}
749	};
750
751	=item regex => $accept[, $reject[, $skip], $cb->($data)	1488	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
752		1489
753	Makes a regex match against the regex object C<$accept> and returns	1490	Makes a regex match against the regex object C<$accept> and returns
754	everything up to and including the match.	1491	everything up to and including the match.
755		1492
756	Example: read a single line terminated by '\n'.	1493	Example: read a single line terminated by '\n'.
…		…
772	the receive buffer when neither C<$accept> nor C<$reject> match,	1509	the receive buffer when neither C<$accept> nor C<$reject> match,
773	and everything preceding and including the match will be accepted	1510	and everything preceding and including the match will be accepted
774	unconditionally. This is useful to skip large amounts of data that you	1511	unconditionally. This is useful to skip large amounts of data that you
775	know cannot be matched, so that the C<$accept> or C<$reject> regex do not	1512	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
776	have to start matching from the beginning. This is purely an optimisation	1513	have to start matching from the beginning. This is purely an optimisation
777	and is usually worth only when you expect more than a few kilobytes.	1514	and is usually worth it only when you expect more than a few kilobytes.
778		1515
779	Example: expect a http header, which ends at C<\015\012\015\012>. Since we	1516	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
780	expect the header to be very large (it isn't in practise, but...), we use	1517	expect the header to be very large (it isn't in practice, but...), we use
781	a skip regex to skip initial portions. The skip regex is tricky in that	1518	a skip regex to skip initial portions. The skip regex is tricky in that
782	it only accepts something not ending in either \015 or \012, as these are	1519	it only accepts something not ending in either \015 or \012, as these are
783	required for the accept regex.	1520	required for the accept regex.
784		1521
785	$handle->push_read (regex =>	1522	$handle->push_read (regex =>
…		…
804	return 1;	1541	return 1;
805	}	1542	}
806		1543
807	# reject	1544	# reject
808	if ($reject && $$rbuf =~ $reject) {	1545	if ($reject && $$rbuf =~ $reject) {
809	$! = &Errno::EBADMSG;	1546	$self->_error (Errno::EBADMSG);
810	$self->error;
811	}	1547	}
812		1548
813	# skip	1549	# skip
814	if ($skip && $$rbuf =~ $skip) {	1550	if ($skip && $$rbuf =~ $skip) {
815	$data .= substr $$rbuf, 0, $+[0], "";	1551	$data .= substr $$rbuf, 0, $+[0], "";
…		…
817		1553
818	()	1554	()
819	}	1555	}
820	};	1556	};
821		1557
		1558	=item netstring => $cb->($handle, $string)
		1559
		1560	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1561
		1562	Throws an error with C<$!> set to EBADMSG on format violations.
		1563
		1564	=cut
		1565
		1566	register_read_type netstring => sub {
		1567	my ($self, $cb) = @_;
		1568
		1569	sub {
		1570	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1571	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1572	$self->_error (Errno::EBADMSG);
		1573	}
		1574	return;
		1575	}
		1576
		1577	my $len = $1;
		1578
		1579	$self->unshift_read (chunk => $len, sub {
		1580	my $string = $_[1];
		1581	$_[0]->unshift_read (chunk => 1, sub {
		1582	if ($_[1] eq ",") {
		1583	$cb->($_[0], $string);
		1584	} else {
		1585	$self->_error (Errno::EBADMSG);
		1586	}
		1587	});
		1588	});
		1589
		1590	1
		1591	}
		1592	};
		1593
		1594	=item packstring => $format, $cb->($handle, $string)
		1595
		1596	An octet string prefixed with an encoded length. The encoding C<$format>
		1597	uses the same format as a Perl C<pack> format, but must specify a single
		1598	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1599	optional C<!>, C<< < >> or C<< > >> modifier).
		1600
		1601	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1602	EPP uses a prefix of C<N> (4 octtes).
		1603
		1604	Example: read a block of data prefixed by its length in BER-encoded
		1605	format (very efficient).
		1606
		1607	$handle->push_read (packstring => "w", sub {
		1608	my ($handle, $data) = @_;
		1609	});
		1610
		1611	=cut
		1612
		1613	register_read_type packstring => sub {
		1614	my ($self, $cb, $format) = @_;
		1615
		1616	sub {
		1617	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1618	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1619	or return;
		1620
		1621	$format = length pack $format, $len;
		1622
		1623	# bypass unshift if we already have the remaining chunk
		1624	if ($format + $len <= length $_[0]{rbuf}) {
		1625	my $data = substr $_[0]{rbuf}, $format, $len;
		1626	substr $_[0]{rbuf}, 0, $format + $len, "";
		1627	$cb->($_[0], $data);
		1628	} else {
		1629	# remove prefix
		1630	substr $_[0]{rbuf}, 0, $format, "";
		1631
		1632	# read remaining chunk
		1633	$_[0]->unshift_read (chunk => $len, $cb);
		1634	}
		1635
		1636	1
		1637	}
		1638	};
		1639
		1640	=item json => $cb->($handle, $hash_or_arrayref)
		1641
		1642	Reads a JSON object or array, decodes it and passes it to the
		1643	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1644
		1645	If a C<json> object was passed to the constructor, then that will be used
		1646	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1647
		1648	This read type uses the incremental parser available with JSON version
		1649	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1650	dependency on your own: this module will load the JSON module, but
		1651	AnyEvent does not depend on it itself.
		1652
		1653	Since JSON texts are fully self-delimiting, the C<json> read and write
		1654	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1655	the C<json> write type description, above, for an actual example.
		1656
		1657	=cut
		1658
		1659	register_read_type json => sub {
		1660	my ($self, $cb) = @_;
		1661
		1662	my $json = $self->{json} ||= json_coder;
		1663
		1664	my $data;
		1665	my $rbuf = \$self->{rbuf};
		1666
		1667	sub {
		1668	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1669
		1670	if ($ref) {
		1671	$self->{rbuf} = $json->incr_text;
		1672	$json->incr_text = "";
		1673	$cb->($self, $ref);
		1674
		1675	1
		1676	} elsif ($@) {
		1677	# error case
		1678	$json->incr_skip;
		1679
		1680	$self->{rbuf} = $json->incr_text;
		1681	$json->incr_text = "";
		1682
		1683	$self->_error (Errno::EBADMSG);
		1684
		1685	()
		1686	} else {
		1687	$self->{rbuf} = "";
		1688
		1689	()
		1690	}
		1691	}
		1692	};
		1693
		1694	=item storable => $cb->($handle, $ref)
		1695
		1696	Deserialises a L<Storable> frozen representation as written by the
		1697	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1698	data).
		1699
		1700	Raises C<EBADMSG> error if the data could not be decoded.
		1701
		1702	=cut
		1703
		1704	register_read_type storable => sub {
		1705	my ($self, $cb) = @_;
		1706
		1707	require Storable;
		1708
		1709	sub {
		1710	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1711	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1712	or return;
		1713
		1714	my $format = length pack "w", $len;
		1715
		1716	# bypass unshift if we already have the remaining chunk
		1717	if ($format + $len <= length $_[0]{rbuf}) {
		1718	my $data = substr $_[0]{rbuf}, $format, $len;
		1719	substr $_[0]{rbuf}, 0, $format + $len, "";
		1720	$cb->($_[0], Storable::thaw ($data));
		1721	} else {
		1722	# remove prefix
		1723	substr $_[0]{rbuf}, 0, $format, "";
		1724
		1725	# read remaining chunk
		1726	$_[0]->unshift_read (chunk => $len, sub {
		1727	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1728	$cb->($_[0], $ref);
		1729	} else {
		1730	$self->_error (Errno::EBADMSG);
		1731	}
		1732	});
		1733	}
		1734
		1735	1
		1736	}
		1737	};
		1738
822	=back	1739	=back
823		1740
824	=item AnyEvent::Handle::register_read_type type => $coderef->($self, $cb, @args)	1741	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
825		1742
826	This function (not method) lets you add your own types to C<push_read>.	1743	Instead of one of the predefined types, you can also specify the name
		1744	of a package. AnyEvent will try to load the package and then expects to
		1745	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1746	progressively tries to load the parent package until it either finds the
		1747	function (good) or runs out of packages (bad).
827		1748
828	Whenever the given C<type> is used, C<push_read> will invoke the code	1749	Whenever this type is used, C<push_read> will invoke the function with the
829	reference with the handle object, the callback and the remaining	1750	handle object, the original callback and the remaining arguments.
830	arguments.
831		1751
832	The code reference is supposed to return a callback (usually a closure)	1752	The function is supposed to return a callback (usually a closure) that
833	that works as a plain read callback (see C<< ->push_read ($cb) >>).	1753	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1754	mentally treat the function as a "configurable read type to read callback"
		1755	converter.
834		1756
835	It should invoke the passed callback when it is done reading (remember to	1757	It should invoke the original callback when it is done reading (remember
836	pass C<$self> as first argument as all other callbacks do that).	1758	to pass C<$handle> as first argument as all other callbacks do that,
		1759	although there is no strict requirement on this).
837		1760
838	Note that this is a function, and all types registered this way will be
839	global, so try to use unique names.
840
841	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,	1761	For examples, see the source of this module (F<perldoc -m
842	search for C<register_read_type>)).	1762	AnyEvent::Handle>, search for C<register_read_type>)).
843		1763
844	=item $handle->stop_read	1764	=item $handle->stop_read
845		1765
846	=item $handle->start_read	1766	=item $handle->start_read
847		1767
848	In rare cases you actually do not want to read anything from the	1768	In rare cases you actually do not want to read anything from the
849	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1769	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
850	any queued callbacks will be executed then. To start reading again, call	1770	any queued callbacks will be executed then. To start reading again, call
851	C<start_read>.	1771	C<start_read>.
852		1772
		1773	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1774	you change the C<on_read> callback or push/unshift a read callback, and it
		1775	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1776	there are any read requests in the queue.
		1777
		1778	In older versions of this module (<= 5.3), these methods had no effect,
		1779	as TLS does not support half-duplex connections. In current versions they
		1780	work as expected, as this behaviour is required to avoid certain resource
		1781	attacks, where the program would be forced to read (and buffer) arbitrary
		1782	amounts of data before being able to send some data. The drawback is that
		1783	some readings of the the SSL/TLS specifications basically require this
		1784	attack to be working, as SSL/TLS implementations might stall sending data
		1785	during a rehandshake.
		1786
		1787	As a guideline, during the initial handshake, you should not stop reading,
		1788	and as a client, it might cause problems, depending on your applciation.
		1789
853	=cut	1790	=cut
854		1791
855	sub stop_read {	1792	sub stop_read {
856	my ($self) = @_;	1793	my ($self) = @_;
857		1794
…		…
859	}	1796	}
860		1797
861	sub start_read {	1798	sub start_read {
862	my ($self) = @_;	1799	my ($self) = @_;
863		1800
864	unless ($self->{_rw} || $self->{_eof}) {	1801	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
865	Scalar::Util::weaken $self;	1802	Scalar::Util::weaken $self;
866		1803
867	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1804	$self->{_rw} = AE::io $self->{fh}, 0, sub {
868	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1805	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
869	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1806	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
870		1807
871	if ($len > 0) {	1808	if ($len > 0) {
872	$self->{filter_r}	1809	$self->{_activity} = $self->{_ractivity} = AE::now;
873	? $self->{filter_r}->($self, $rbuf)	1810
		1811	if ($self->{tls}) {
		1812	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1813
		1814	&_dotls ($self);
		1815	} else {
874	: $self->_drain_rbuf;	1816	$self->_drain_rbuf;
		1817	}
		1818
		1819	if ($len == $self->{read_size}) {
		1820	$self->{read_size} *= 2;
		1821	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		1822	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		1823	}
875		1824
876	} elsif (defined $len) {	1825	} elsif (defined $len) {
877	delete $self->{_rw};	1826	delete $self->{_rw};
878	$self->{_eof} = 1;	1827	$self->{_eof} = 1;
879	$self->_drain_rbuf;	1828	$self->_drain_rbuf;
880		1829
881	} elsif ($! != EAGAIN && $! != EINTR && $! != &AnyEvent::Util::WSAWOULDBLOCK) {	1830	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
882	return $self->error;	1831	return $self->_error ($!, 1);
883	}	1832	}
884	});	1833	};
885	}	1834	}
886	}	1835	}
887		1836
		1837	our $ERROR_SYSCALL;
		1838	our $ERROR_WANT_READ;
		1839
		1840	sub _tls_error {
		1841	my ($self, $err) = @_;
		1842
		1843	return $self->_error ($!, 1)
		1844	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1845
		1846	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1847
		1848	# reduce error string to look less scary
		1849	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1850
		1851	if ($self->{_on_starttls}) {
		1852	(delete $self->{_on_starttls})->($self, undef, $err);
		1853	&_freetls;
		1854	} else {
		1855	&_freetls;
		1856	$self->_error (Errno::EPROTO, 1, $err);
		1857	}
		1858	}
		1859
		1860	# poll the write BIO and send the data if applicable
		1861	# also decode read data if possible
		1862	# this is basiclaly our TLS state machine
		1863	# more efficient implementations are possible with openssl,
		1864	# but not with the buggy and incomplete Net::SSLeay.
888	sub _dotls {	1865	sub _dotls {
889	my ($self) = @_;	1866	my ($self) = @_;
890		1867
		1868	my $tmp;
		1869
891	if (length $self->{_tls_wbuf}) {	1870	if (length $self->{_tls_wbuf}) {
892	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {	1871	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
893	substr $self->{_tls_wbuf}, 0, $len, "";	1872	substr $self->{_tls_wbuf}, 0, $tmp, "";
894	}	1873	}
895	}
896		1874
		1875	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1876	return $self->_tls_error ($tmp)
		1877	if $tmp != $ERROR_WANT_READ
		1878	&& ($tmp != $ERROR_SYSCALL || $!);
		1879	}
		1880
		1881	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1882	unless (length $tmp) {
		1883	$self->{_on_starttls}
		1884	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1885	&_freetls;
		1886
		1887	if ($self->{on_stoptls}) {
		1888	$self->{on_stoptls}($self);
		1889	return;
		1890	} else {
		1891	# let's treat SSL-eof as we treat normal EOF
		1892	delete $self->{_rw};
		1893	$self->{_eof} = 1;
		1894	}
		1895	}
		1896
		1897	$self->{_tls_rbuf} .= $tmp;
		1898	$self->_drain_rbuf;
		1899	$self->{tls} or return; # tls session might have gone away in callback
		1900	}
		1901
		1902	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1903	return $self->_tls_error ($tmp)
		1904	if $tmp != $ERROR_WANT_READ
		1905	&& ($tmp != $ERROR_SYSCALL || $!);
		1906
897	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {	1907	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
898	$self->{wbuf} .= $buf;	1908	$self->{wbuf} .= $tmp;
899	$self->_drain_wbuf;	1909	$self->_drain_wbuf;
		1910	$self->{tls} or return; # tls session might have gone away in callback
900	}	1911	}
901		1912
902	while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {	1913	$self->{_on_starttls}
903	$self->{rbuf} .= $buf;	1914	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
904	$self->_drain_rbuf;	1915	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
905	}
906
907	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
908
909	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
910	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
911	$self->error;
912	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
913	$! = &Errno::EIO;
914	$self->error;
915	}
916
917	# all others are fine for our purposes
918	}
919	}	1916	}
920		1917
921	=item $handle->starttls ($tls[, $tls_ctx])	1918	=item $handle->starttls ($tls[, $tls_ctx])
922		1919
923	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1920	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
924	object is created, you can also do that at a later time by calling	1921	object is created, you can also do that at a later time by calling
925	C<starttls>.	1922	C<starttls>.
926		1923
		1924	Starting TLS is currently an asynchronous operation - when you push some
		1925	write data and then call C<< ->starttls >> then TLS negotiation will start
		1926	immediately, after which the queued write data is then sent.
		1927
927	The first argument is the same as the C<tls> constructor argument (either	1928	The first argument is the same as the C<tls> constructor argument (either
928	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1929	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
929		1930
930	The second argument is the optional C<Net::SSLeay::CTX> object that is	1931	The second argument is the optional C<AnyEvent::TLS> object that is used
931	used when AnyEvent::Handle has to create its own TLS connection object.	1932	when AnyEvent::Handle has to create its own TLS connection object, or
		1933	a hash reference with C<< key => value >> pairs that will be used to
		1934	construct a new context.
932		1935
933	The TLS connection object will end up in C<< $handle->{tls} >> after this	1936	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
934	call and can be used or changed to your liking. Note that the handshake	1937	context in C<< $handle->{tls_ctx} >> after this call and can be used or
935	might have already started when this function returns.	1938	changed to your liking. Note that the handshake might have already started
		1939	when this function returns.
936		1940
937	=cut	1941	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1942	handshakes on the same stream. It is best to not attempt to use the
		1943	stream after stopping TLS.
938		1944
939	# TODO: maybe document...	1945	This method may invoke callbacks (and therefore the handle might be
		1946	destroyed after it returns).
		1947
		1948	=cut
		1949
		1950	our %TLS_CACHE; #TODO not yet documented, should we?
		1951
940	sub starttls {	1952	sub starttls {
941	my ($self, $ssl, $ctx) = @_;	1953	my ($self, $tls, $ctx) = @_;
942		1954
943	$self->stoptls;	1955	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1956	if $self->{tls};
944		1957
945	if ($ssl eq "accept") {	1958	$self->{tls} = $tls;
946	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1959	$self->{tls_ctx} = $ctx if @_ > 2;
947	Net::SSLeay::set_accept_state ($ssl);	1960
948	} elsif ($ssl eq "connect") {	1961	return unless $self->{fh};
949	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1962
950	Net::SSLeay::set_connect_state ($ssl);	1963	require Net::SSLeay;
		1964
		1965	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1966	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1967
		1968	$tls = delete $self->{tls};
		1969	$ctx = $self->{tls_ctx};
		1970
		1971	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1972
		1973	if ("HASH" eq ref $ctx) {
		1974	require AnyEvent::TLS;
		1975
		1976	if ($ctx->{cache}) {
		1977	my $key = $ctx+0;
		1978	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1979	} else {
		1980	$ctx = new AnyEvent::TLS %$ctx;
		1981	}
		1982	}
951	}	1983
952		1984	$self->{tls_ctx} = $ctx || TLS_CTX ();
953	$self->{tls} = $ssl;	1985	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
954		1986
955	# basically, this is deep magic (because SSL_read should have the same issues)	1987	# basically, this is deep magic (because SSL_read should have the same issues)
956	# but the openssl maintainers basically said: "trust us, it just works".	1988	# but the openssl maintainers basically said: "trust us, it just works".
957	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1989	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
958	# and mismaintained ssleay-module doesn't even offer them).	1990	# and mismaintained ssleay-module doesn't even offer them).
959	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1991	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1992	#
		1993	# in short: this is a mess.
		1994	#
		1995	# note that we do not try to keep the length constant between writes as we are required to do.
		1996	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1997	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1998	# have identity issues in that area.
960	Net::SSLeay::CTX_set_mode ($self->{tls},	1999	# Net::SSLeay::CTX_set_mode ($ssl,
961	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	2000	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
962	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	2001	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		2002	Net::SSLeay::CTX_set_mode ($tls, 1|2);
963		2003
964	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2004	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
965	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2005	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
966		2006
		2007	Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf});
		2008
967	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});	2009	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
968		2010
969	$self->{filter_w} = sub {	2011	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
970	$_[0]{_tls_wbuf} .= ${$_[1]};	2012	if $self->{on_starttls};
971	&_dotls;	2013
972	};	2014	&_dotls; # need to trigger the initial handshake
973	$self->{filter_r} = sub {	2015	$self->start_read; # make sure we actually do read
974	Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
975	&_dotls;
976	};
977	}	2016	}
978		2017
979	=item $handle->stoptls	2018	=item $handle->stoptls
980		2019
981	Destroys the SSL connection, if any. Partial read or write data will be	2020	Shuts down the SSL connection - this makes a proper EOF handshake by
982	lost.	2021	sending a close notify to the other side, but since OpenSSL doesn't
		2022	support non-blocking shut downs, it is not guaranteed that you can re-use
		2023	the stream afterwards.
		2024
		2025	This method may invoke callbacks (and therefore the handle might be
		2026	destroyed after it returns).
983		2027
984	=cut	2028	=cut
985		2029
986	sub stoptls {	2030	sub stoptls {
987	my ($self) = @_;	2031	my ($self) = @_;
988		2032
989	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	2033	if ($self->{tls} && $self->{fh}) {
		2034	Net::SSLeay::shutdown ($self->{tls});
990		2035
991	delete $self->{_rbio};	2036	&_dotls;
992	delete $self->{_wbio};	2037
993	delete $self->{_tls_wbuf};	2038	# # we don't give a shit. no, we do, but we can't. no...#d#
994	delete $self->{filter_r};	2039	# # we, we... have to use openssl :/#d#
995	delete $self->{filter_w};	2040	# &_freetls;#d#
		2041	}
		2042	}
		2043
		2044	sub _freetls {
		2045	my ($self) = @_;
		2046
		2047	return unless $self->{tls};
		2048
		2049	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2050	if $self->{tls} > 0;
		2051
		2052	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
996	}	2053	}
997		2054
998	sub DESTROY {	2055	sub DESTROY {
999	my $self = shift;	2056	my ($self) = @_;
1000		2057
1001	$self->stoptls;	2058	&_freetls;
		2059
		2060	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		2061
		2062	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2063	my $fh = delete $self->{fh};
		2064	my $wbuf = delete $self->{wbuf};
		2065
		2066	my @linger;
		2067
		2068	push @linger, AE::io $fh, 1, sub {
		2069	my $len = syswrite $fh, $wbuf, length $wbuf;
		2070
		2071	if ($len > 0) {
		2072	substr $wbuf, 0, $len, "";
		2073	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
		2074	@linger = (); # end
		2075	}
		2076	};
		2077	push @linger, AE::timer $linger, 0, sub {
		2078	@linger = ();
		2079	};
		2080	}
1002	}	2081	}
		2082
		2083	=item $handle->destroy
		2084
		2085	Shuts down the handle object as much as possible - this call ensures that
		2086	no further callbacks will be invoked and as many resources as possible
		2087	will be freed. Any method you will call on the handle object after
		2088	destroying it in this way will be silently ignored (and it will return the
		2089	empty list).
		2090
		2091	Normally, you can just "forget" any references to an AnyEvent::Handle
		2092	object and it will simply shut down. This works in fatal error and EOF
		2093	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2094	callback, so when you want to destroy the AnyEvent::Handle object from
		2095	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2096	that case.
		2097
		2098	Destroying the handle object in this way has the advantage that callbacks
		2099	will be removed as well, so if those are the only reference holders (as
		2100	is common), then one doesn't need to do anything special to break any
		2101	reference cycles.
		2102
		2103	The handle might still linger in the background and write out remaining
		2104	data, as specified by the C<linger> option, however.
		2105
		2106	=cut
		2107
		2108	sub destroy {
		2109	my ($self) = @_;
		2110
		2111	$self->DESTROY;
		2112	%$self = ();
		2113	bless $self, "AnyEvent::Handle::destroyed";
		2114	}
		2115
		2116	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2117	#nop
		2118	}
		2119
		2120	=item $handle->destroyed
		2121
		2122	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2123	->destroy >>, true otherwise.
		2124
		2125	Can be useful to decide whether the handle is still valid after some
		2126	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2127	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2128	can destroy the handle, so work can be avoided by checking sometimes:
		2129
		2130	$hdl->starttls ("accept");
		2131	return if $hdl->destroyed;
		2132	$hdl->push_write (...
		2133
		2134	Note that the call to C<push_write> will silently be ignored if the handle
		2135	has been destroyed, so often you can just ignore the possibility of the
		2136	handle being destroyed.
		2137
		2138	=cut
		2139
		2140	sub destroyed { 0 }
		2141	sub AnyEvent::Handle::destroyed::destroyed { 1 }
1003		2142
1004	=item AnyEvent::Handle::TLS_CTX	2143	=item AnyEvent::Handle::TLS_CTX
1005		2144
1006	This function creates and returns the Net::SSLeay::CTX object used by	2145	This function creates and returns the AnyEvent::TLS object used by default
1007	default for TLS mode.	2146	for TLS mode.
1008		2147
1009	The context is created like this:	2148	The context is created by calling L<AnyEvent::TLS> without any arguments.
1010
1011	Net::SSLeay::load_error_strings;
1012	Net::SSLeay::SSLeay_add_ssl_algorithms;
1013	Net::SSLeay::randomize;
1014
1015	my $CTX = Net::SSLeay::CTX_new;
1016
1017	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
1018		2149
1019	=cut	2150	=cut
1020		2151
1021	our $TLS_CTX;	2152	our $TLS_CTX;
1022		2153
1023	sub TLS_CTX() {	2154	sub TLS_CTX() {
1024	$TLS_CTX || do {	2155	$TLS_CTX ||= do {
1025	require Net::SSLeay;	2156	require AnyEvent::TLS;
1026		2157
1027	Net::SSLeay::load_error_strings ();	2158	new AnyEvent::TLS
1028	Net::SSLeay::SSLeay_add_ssl_algorithms ();
1029	Net::SSLeay::randomize ();
1030
1031	$TLS_CTX = Net::SSLeay::CTX_new ();
1032
1033	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
1034
1035	$TLS_CTX
1036	}	2159	}
1037	}	2160	}
1038		2161
1039	=back	2162	=back
		2163
		2164
		2165	=head1 NONFREQUENTLY ASKED QUESTIONS
		2166
		2167	=over 4
		2168
		2169	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2170	still get further invocations!
		2171
		2172	That's because AnyEvent::Handle keeps a reference to itself when handling
		2173	read or write callbacks.
		2174
		2175	It is only safe to "forget" the reference inside EOF or error callbacks,
		2176	from within all other callbacks, you need to explicitly call the C<<
		2177	->destroy >> method.
		2178
		2179	=item Why is my C<on_eof> callback never called?
		2180
		2181	Probably because your C<on_error> callback is being called instead: When
		2182	you have outstanding requests in your read queue, then an EOF is
		2183	considered an error as you clearly expected some data.
		2184
		2185	To avoid this, make sure you have an empty read queue whenever your handle
		2186	is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
		2187	an C<on_read> handler that simply pushes the first read requests in the
		2188	queue.
		2189
		2190	See also the next question, which explains this in a bit more detail.
		2191
		2192	=item How can I serve requests in a loop?
		2193
		2194	Most protocols consist of some setup phase (authentication for example)
		2195	followed by a request handling phase, where the server waits for requests
		2196	and handles them, in a loop.
		2197
		2198	There are two important variants: The first (traditional, better) variant
		2199	handles requests until the server gets some QUIT command, causing it to
		2200	close the connection first (highly desirable for a busy TCP server). A
		2201	client dropping the connection is an error, which means this variant can
		2202	detect an unexpected detection close.
		2203
		2204	To handle this case, always make sure you have a on-empty read queue, by
		2205	pushing the "read request start" handler on it:
		2206
		2207	# we assume a request starts with a single line
		2208	my @start_request; @start_request = (line => sub {
		2209	my ($hdl, $line) = @_;
		2210
		2211	... handle request
		2212
		2213	# push next request read, possibly from a nested callback
		2214	$hdl->push_read (@start_request);
		2215	});
		2216
		2217	# auth done, now go into request handling loop
		2218	# now push the first @start_request
		2219	$hdl->push_read (@start_request);
		2220
		2221	By always having an outstanding C<push_read>, the handle always expects
		2222	some data and raises the C<EPIPE> error when the connction is dropped
		2223	unexpectedly.
		2224
		2225	The second variant is a protocol where the client can drop the connection
		2226	at any time. For TCP, this means that the server machine may run out of
		2227	sockets easier, and in general, it means you cnanot distinguish a protocl
		2228	failure/client crash from a normal connection close. Nevertheless, these
		2229	kinds of protocols are common (and sometimes even the best solution to the
		2230	problem).
		2231
		2232	Having an outstanding read request at all times is possible if you ignore
		2233	C<EPIPE> errors, but this doesn't help with when the client drops the
		2234	connection during a request, which would still be an error.
		2235
		2236	A better solution is to push the initial request read in an C<on_read>
		2237	callback. This avoids an error, as when the server doesn't expect data
		2238	(i.e. is idly waiting for the next request, an EOF will not raise an
		2239	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2240	and simpler:
		2241
		2242	# auth done, now go into request handling loop
		2243	$hdl->on_read (sub {
		2244	my ($hdl) = @_;
		2245
		2246	# called each time we receive data but the read queue is empty
		2247	# simply start read the request
		2248
		2249	$hdl->push_read (line => sub {
		2250	my ($hdl, $line) = @_;
		2251
		2252	... handle request
		2253
		2254	# do nothing special when the request has been handled, just
		2255	# let the request queue go empty.
		2256	});
		2257	});
		2258
		2259	=item I get different callback invocations in TLS mode/Why can't I pause
		2260	reading?
		2261
		2262	Unlike, say, TCP, TLS connections do not consist of two independent
		2263	communication channels, one for each direction. Or put differently, the
		2264	read and write directions are not independent of each other: you cannot
		2265	write data unless you are also prepared to read, and vice versa.
		2266
		2267	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2268	callback invocations when you are not expecting any read data - the reason
		2269	is that AnyEvent::Handle always reads in TLS mode.
		2270
		2271	During the connection, you have to make sure that you always have a
		2272	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2273	connection (or when you no longer want to use it) you can call the
		2274	C<destroy> method.
		2275
		2276	=item How do I read data until the other side closes the connection?
		2277
		2278	If you just want to read your data into a perl scalar, the easiest way
		2279	to achieve this is by setting an C<on_read> callback that does nothing,
		2280	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2281	will be in C<$_[0]{rbuf}>:
		2282
		2283	$handle->on_read (sub { });
		2284	$handle->on_eof (undef);
		2285	$handle->on_error (sub {
		2286	my $data = delete $_[0]{rbuf};
		2287	});
		2288
		2289	The reason to use C<on_error> is that TCP connections, due to latencies
		2290	and packets loss, might get closed quite violently with an error, when in
		2291	fact all data has been received.
		2292
		2293	It is usually better to use acknowledgements when transferring data,
		2294	to make sure the other side hasn't just died and you got the data
		2295	intact. This is also one reason why so many internet protocols have an
		2296	explicit QUIT command.
		2297
		2298	=item I don't want to destroy the handle too early - how do I wait until
		2299	all data has been written?
		2300
		2301	After writing your last bits of data, set the C<on_drain> callback
		2302	and destroy the handle in there - with the default setting of
		2303	C<low_water_mark> this will be called precisely when all data has been
		2304	written to the socket:
		2305
		2306	$handle->push_write (...);
		2307	$handle->on_drain (sub {
		2308	warn "all data submitted to the kernel\n";
		2309	undef $handle;
		2310	});
		2311
		2312	If you just want to queue some data and then signal EOF to the other side,
		2313	consider using C<< ->push_shutdown >> instead.
		2314
		2315	=item I want to contact a TLS/SSL server, I don't care about security.
		2316
		2317	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2318	connect to it and then create the AnyEvent::Handle with the C<tls>
		2319	parameter:
		2320
		2321	tcp_connect $host, $port, sub {
		2322	my ($fh) = @_;
		2323
		2324	my $handle = new AnyEvent::Handle
		2325	fh => $fh,
		2326	tls => "connect",
		2327	on_error => sub { ... };
		2328
		2329	$handle->push_write (...);
		2330	};
		2331
		2332	=item I want to contact a TLS/SSL server, I do care about security.
		2333
		2334	Then you should additionally enable certificate verification, including
		2335	peername verification, if the protocol you use supports it (see
		2336	L<AnyEvent::TLS>, C<verify_peername>).
		2337
		2338	E.g. for HTTPS:
		2339
		2340	tcp_connect $host, $port, sub {
		2341	my ($fh) = @_;
		2342
		2343	my $handle = new AnyEvent::Handle
		2344	fh => $fh,
		2345	peername => $host,
		2346	tls => "connect",
		2347	tls_ctx => { verify => 1, verify_peername => "https" },
		2348	...
		2349
		2350	Note that you must specify the hostname you connected to (or whatever
		2351	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2352	peername verification will be done.
		2353
		2354	The above will use the system-dependent default set of trusted CA
		2355	certificates. If you want to check against a specific CA, add the
		2356	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2357
		2358	tls_ctx => {
		2359	verify => 1,
		2360	verify_peername => "https",
		2361	ca_file => "my-ca-cert.pem",
		2362	},
		2363
		2364	=item I want to create a TLS/SSL server, how do I do that?
		2365
		2366	Well, you first need to get a server certificate and key. You have
		2367	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2368	self-signed certificate (cheap. check the search engine of your choice,
		2369	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2370	nice program for that purpose).
		2371
		2372	Then create a file with your private key (in PEM format, see
		2373	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2374	file should then look like this:
		2375
		2376	-----BEGIN RSA PRIVATE KEY-----
		2377	...header data
		2378	... lots of base64'y-stuff
		2379	-----END RSA PRIVATE KEY-----
		2380
		2381	-----BEGIN CERTIFICATE-----
		2382	... lots of base64'y-stuff
		2383	-----END CERTIFICATE-----
		2384
		2385	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2386	specify this file as C<cert_file>:
		2387
		2388	tcp_server undef, $port, sub {
		2389	my ($fh) = @_;
		2390
		2391	my $handle = new AnyEvent::Handle
		2392	fh => $fh,
		2393	tls => "accept",
		2394	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2395	...
		2396
		2397	When you have intermediate CA certificates that your clients might not
		2398	know about, just append them to the C<cert_file>.
		2399
		2400	=back
		2401
1040		2402
1041	=head1 SUBCLASSING AnyEvent::Handle	2403	=head1 SUBCLASSING AnyEvent::Handle
1042		2404
1043	In many cases, you might want to subclass AnyEvent::Handle.	2405	In many cases, you might want to subclass AnyEvent::Handle.
1044		2406
…		…
1048	=over 4	2410	=over 4
1049		2411
1050	=item * all constructor arguments become object members.	2412	=item * all constructor arguments become object members.
1051		2413
1052	At least initially, when you pass a C<tls>-argument to the constructor it	2414	At least initially, when you pass a C<tls>-argument to the constructor it
1053	will end up in C<< $handle->{tls} >>. Those members might be changes or	2415	will end up in C<< $handle->{tls} >>. Those members might be changed or
1054	mutated later on (for example C<tls> will hold the TLS connection object).	2416	mutated later on (for example C<tls> will hold the TLS connection object).
1055		2417
1056	=item * other object member names are prefixed with an C<_>.	2418	=item * other object member names are prefixed with an C<_>.
1057		2419
1058	All object members not explicitly documented (internal use) are prefixed	2420	All object members not explicitly documented (internal use) are prefixed
…		…
1061		2423
1062	=item * all members not documented here and not prefixed with an underscore	2424	=item * all members not documented here and not prefixed with an underscore
1063	are free to use in subclasses.	2425	are free to use in subclasses.
1064		2426
1065	Of course, new versions of AnyEvent::Handle may introduce more "public"	2427	Of course, new versions of AnyEvent::Handle may introduce more "public"
1066	member variables, but thats just life, at least it is documented.	2428	member variables, but that's just life. At least it is documented.
1067		2429
1068	=back	2430	=back
1069		2431
1070	=head1 AUTHOR	2432	=head1 AUTHOR
1071		2433

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