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Revision 1.219 by root, Mon Jul 18 01:19:43 2011 UTC

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict;
5
6	use AnyEvent ();
7	use AnyEvent::Util ();
8	use Scalar::Util ();
9	use Carp ();
10	use Fcntl ();
11	use Errno qw/EAGAIN EINTR/;
12
13	=head1 NAME	1	=head1 NAME
14		2
15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent	3	AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
16
17	=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
		180	C<EPROTO>).
97		181
98	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
99	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
100	die.	184	C<croak>.
101		185
102	=item on_read => $cb->($self)	186	=item on_read => $cb->($handle)
103		187
104	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
105	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).
106		192
107	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 >>
108	method or access the C<$self->{rbuf}> member directly.	194	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		195	must not enlarge or modify the read buffer, you can only remove data at
		196	the beginning from it.
109		197
		198	You can also call C<< ->push_read (...) >> or any other function that
		199	modifies the read queue. Or do both. Or ...
		200
110	When an EOF condition is detected then AnyEvent::Handle will first try to	201	When an EOF condition is detected, AnyEvent::Handle will first try to
111	feed all the remaining data to the queued callbacks and C<on_read> before	202	feed all the remaining data to the queued callbacks and C<on_read> before
112	calling the C<on_eof> callback. If no progress can be made, then a fatal	203	calling the C<on_eof> callback. If no progress can be made, then a fatal
113	error will be raised (with C<$!> set to C<EPIPE>).	204	error will be raised (with C<$!> set to C<EPIPE>).
114		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
115	=item on_drain => $cb->()	227	=item on_drain => $cb->($handle)
116		228
117	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
118	(or when the callback is set and the buffer is empty already).	230	(or immediately if the buffer is empty already).
119		231
120	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 of each
		253	other, for both read and write (triggered when nothing was read I<OR>
		254	written), just read (triggered when nothing was read), and just write:
		255	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		256	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		257	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		258
		259	Note that timeout processing is active even when you do not have any
		260	outstanding read or write requests: If you plan to keep the connection
		261	idle then you should disable the timeout temporarily or ignore the
		262	timeout in the corresponding C<on_timeout> callback, in which case
		263	AnyEvent::Handle will simply restart the timeout.
		264
		265	Zero (the default) disables the corresponding timeout.
		266
		267	=item on_timeout => $cb->($handle)
		268
		269	=item on_rtimeout => $cb->($handle)
		270
		271	=item on_wtimeout => $cb->($handle)
		272
		273	Called whenever the inactivity timeout passes. If you return from this
		274	callback, then the timeout will be reset as if some activity had happened,
		275	so this condition is not fatal in any way.
121		276
122	=item rbuf_max => <bytes>	277	=item rbuf_max => <bytes>
123		278
124	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	279	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
125	when the read buffer ever (strictly) exceeds this size. This is useful to	280	when the read buffer ever (strictly) exceeds this size. This is useful to
126	avoid denial-of-service attacks.	281	avoid some forms of denial-of-service attacks.
127		282
128	For example, a server accepting connections from untrusted sources should	283	For example, a server accepting connections from untrusted sources should
129	be configured to accept only so-and-so much data that it cannot act on	284	be configured to accept only so-and-so much data that it cannot act on
130	(for example, when expecting a line, an attacker could send an unlimited	285	(for example, when expecting a line, an attacker could send an unlimited
131	amount of data without a callback ever being called as long as the line	286	amount of data without a callback ever being called as long as the line
132	isn't finished).	287	isn't finished).
133		288
		289	=item wbuf_max => <bytes>
		290
		291	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		292	when the write buffer ever (strictly) exceeds this size. This is useful to
		293	avoid some forms of denial-of-service attacks.
		294
		295	Although the units of this parameter is bytes, this is the I<raw> number
		296	of bytes not yet accepted by the kernel. This can make a difference when
		297	you e.g. use TLS, as TLS typically makes your write data larger (but it
		298	can also make it smaller due to compression).
		299
		300	As an example of when this limit is useful, take a chat server that sends
		301	chat messages to a client. If the client does not read those in a timely
		302	manner then the send buffer in the server would grow unbounded.
		303
		304	=item autocork => <boolean>
		305
		306	When disabled (the default), C<push_write> will try to immediately
		307	write the data to the handle if possible. This avoids having to register
		308	a write watcher and wait for the next event loop iteration, but can
		309	be inefficient if you write multiple small chunks (on the wire, this
		310	disadvantage is usually avoided by your kernel's nagle algorithm, see
		311	C<no_delay>, but this option can save costly syscalls).
		312
		313	When enabled, writes will always be queued till the next event loop
		314	iteration. This is efficient when you do many small writes per iteration,
		315	but less efficient when you do a single write only per iteration (or when
		316	the write buffer often is full). It also increases write latency.
		317
		318	=item no_delay => <boolean>
		319
		320	When doing small writes on sockets, your operating system kernel might
		321	wait a bit for more data before actually sending it out. This is called
		322	the Nagle algorithm, and usually it is beneficial.
		323
		324	In some situations you want as low a delay as possible, which can be
		325	accomplishd by setting this option to a true value.
		326
		327	The default is your operating system's default behaviour (most likely
		328	enabled). This option explicitly enables or disables it, if possible.
		329
		330	=item keepalive => <boolean>
		331
		332	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		333	normally, TCP connections have no time-out once established, so TCP
		334	connections, once established, can stay alive forever even when the other
		335	side has long gone. TCP keepalives are a cheap way to take down long-lived
		336	TCP connections when the other side becomes unreachable. While the default
		337	is OS-dependent, TCP keepalives usually kick in after around two hours,
		338	and, if the other side doesn't reply, take down the TCP connection some 10
		339	to 15 minutes later.
		340
		341	It is harmless to specify this option for file handles that do not support
		342	keepalives, and enabling it on connections that are potentially long-lived
		343	is usually a good idea.
		344
		345	=item oobinline => <boolean>
		346
		347	BSD majorly fucked up the implementation of TCP urgent data. The result
		348	is that almost no OS implements TCP according to the specs, and every OS
		349	implements it slightly differently.
		350
		351	If you want to handle TCP urgent data, then setting this flag (the default
		352	is enabled) gives you the most portable way of getting urgent data, by
		353	putting it into the stream.
		354
		355	Since BSD emulation of OOB data on top of TCP's urgent data can have
		356	security implications, AnyEvent::Handle sets this flag automatically
		357	unless explicitly specified. Note that setting this flag after
		358	establishing a connection I<may> be a bit too late (data loss could
		359	already have occured on BSD systems), but at least it will protect you
		360	from most attacks.
		361
134	=item read_size => <bytes>	362	=item read_size => <bytes>
135		363
136	The default read block size (the amount of bytes this module will try to read	364	The initial read block size, the number of bytes this module will try to
137	on each [loop iteration). Default: C<4096>.	365	read during each loop iteration. Each handle object will consume at least
		366	this amount of memory for the read buffer as well, so when handling many
		367	connections requirements). See also C<max_read_size>. Default: C<2048>.
		368
		369	=item max_read_size => <bytes>
		370
		371	The maximum read buffer size used by the dynamic adjustment
		372	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		373	one go it will double C<read_size> up to the maximum given by this
		374	option. Default: C<131072> or C<read_size>, whichever is higher.
138		375
139	=item low_water_mark => <bytes>	376	=item low_water_mark => <bytes>
140		377
141	Sets the amount of bytes (default: C<0>) that make up an "empty" write	378	Sets the number of bytes (default: C<0>) that make up an "empty" write
142	buffer: If the write reaches this size or gets even samller it is	379	buffer: If the buffer reaches this size or gets even samller it is
143	considered empty.	380	considered empty.
144		381
		382	Sometimes it can be beneficial (for performance reasons) to add data to
		383	the write buffer before it is fully drained, but this is a rare case, as
		384	the operating system kernel usually buffers data as well, so the default
		385	is good in almost all cases.
		386
		387	=item linger => <seconds>
		388
		389	If this is non-zero (default: C<3600>), the destructor of the
		390	AnyEvent::Handle object will check whether there is still outstanding
		391	write data and will install a watcher that will write this data to the
		392	socket. No errors will be reported (this mostly matches how the operating
		393	system treats outstanding data at socket close time).
		394
		395	This will not work for partial TLS data that could not be encoded
		396	yet. This data will be lost. Calling the C<stoptls> method in time might
		397	help.
		398
		399	=item peername => $string
		400
		401	A string used to identify the remote site - usually the DNS hostname
		402	(I<not> IDN!) used to create the connection, rarely the IP address.
		403
		404	Apart from being useful in error messages, this string is also used in TLS
		405	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		406	verification will be skipped when C<peername> is not specified or is
		407	C<undef>.
		408
145	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	409	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
146		410
147	When this parameter is given, it enables TLS (SSL) mode, that means it	411	When this parameter is given, it enables TLS (SSL) mode, that means
148	will start making tls handshake and will transparently encrypt/decrypt	412	AnyEvent will start a TLS handshake as soon as the connection has been
149	data.	413	established and will transparently encrypt/decrypt data afterwards.
		414
		415	All TLS protocol errors will be signalled as C<EPROTO>, with an
		416	appropriate error message.
150		417
151	TLS mode requires Net::SSLeay to be installed (it will be loaded	418	TLS mode requires Net::SSLeay to be installed (it will be loaded
152	automatically when you try to create a TLS handle).	419	automatically when you try to create a TLS handle): this module doesn't
		420	have a dependency on that module, so if your module requires it, you have
		421	to add the dependency yourself.
153		422
154	For the TLS server side, use C<accept>, and for the TLS client side of a	423	Unlike TCP, TLS has a server and client side: for the TLS server side, use
155	connection, use C<connect> mode.	424	C<accept>, and for the TLS client side of a connection, use C<connect>
		425	mode.
156		426
157	You can also provide your own TLS connection object, but you have	427	You can also provide your own TLS connection object, but you have
158	to make sure that you call either C<Net::SSLeay::set_connect_state>	428	to make sure that you call either C<Net::SSLeay::set_connect_state>
159	or C<Net::SSLeay::set_accept_state> on it before you pass it to	429	or C<Net::SSLeay::set_accept_state> on it before you pass it to
160	AnyEvent::Handle.	430	AnyEvent::Handle. Also, this module will take ownership of this connection
		431	object.
161		432
		433	At some future point, AnyEvent::Handle might switch to another TLS
		434	implementation, then the option to use your own session object will go
		435	away.
		436
		437	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		438	passing in the wrong integer will lead to certain crash. This most often
		439	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		440	segmentation fault.
		441
162	See the C<starttls> method if you need to start TLs negotiation later.	442	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
163		443
164	=item tls_ctx => $ssl_ctx	444	=item tls_ctx => $anyevent_tls
165		445
166	Use the given Net::SSLeay::CTX object to create the new TLS connection	446	Use the given C<AnyEvent::TLS> object to create the new TLS connection
167	(unless a connection object was specified directly). If this parameter is	447	(unless a connection object was specified directly). If this
168	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	448	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		449	C<AnyEvent::Handle::TLS_CTX>.
		450
		451	Instead of an object, you can also specify a hash reference with C<< key
		452	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		453	new TLS context object.
		454
		455	=item on_starttls => $cb->($handle, $success[, $error_message])
		456
		457	This callback will be invoked when the TLS/SSL handshake has finished. If
		458	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		459	(C<on_stoptls> will not be called in this case).
		460
		461	The session in C<< $handle->{tls} >> can still be examined in this
		462	callback, even when the handshake was not successful.
		463
		464	TLS handshake failures will not cause C<on_error> to be invoked when this
		465	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		466
		467	Without this callback, handshake failures lead to C<on_error> being
		468	called as usual.
		469
		470	Note that you cannot just call C<starttls> again in this callback. If you
		471	need to do that, start an zero-second timer instead whose callback can
		472	then call C<< ->starttls >> again.
		473
		474	=item on_stoptls => $cb->($handle)
		475
		476	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		477	set, then it will be invoked after freeing the TLS session. If it is not,
		478	then a TLS shutdown condition will be treated like a normal EOF condition
		479	on the handle.
		480
		481	The session in C<< $handle->{tls} >> can still be examined in this
		482	callback.
		483
		484	This callback will only be called on TLS shutdowns, not when the
		485	underlying handle signals EOF.
		486
		487	=item json => JSON or JSON::XS object
		488
		489	This is the json coder object used by the C<json> read and write types.
		490
		491	If you don't supply it, then AnyEvent::Handle will create and use a
		492	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		493	texts.
		494
		495	Note that you are responsible to depend on the JSON module if you want to
		496	use this functionality, as AnyEvent does not have a dependency itself.
169		497
170	=back	498	=back
171		499
172	=cut	500	=cut
173		501
174	sub new {	502	sub new {
175	my $class = shift;	503	my $class = shift;
176
177	my $self = bless { @_ }, $class;	504	my $self = bless { @_ }, $class;
178		505
179	$self->{fh} or Carp::croak "mandatory argument fh is missing";	506	if ($self->{fh}) {
		507	$self->_start;
		508	return unless $self->{fh}; # could be gone by now
		509
		510	} elsif ($self->{connect}) {
		511	require AnyEvent::Socket;
		512
		513	$self->{peername} = $self->{connect}[0]
		514	unless exists $self->{peername};
		515
		516	$self->{_skip_drain_rbuf} = 1;
		517
		518	{
		519	Scalar::Util::weaken (my $self = $self);
		520
		521	$self->{_connect} =
		522	AnyEvent::Socket::tcp_connect (
		523	$self->{connect}[0],
		524	$self->{connect}[1],
		525	sub {
		526	my ($fh, $host, $port, $retry) = @_;
		527
		528	delete $self->{_connect}; # no longer needed
		529
		530	if ($fh) {
		531	$self->{fh} = $fh;
		532
		533	delete $self->{_skip_drain_rbuf};
		534	$self->_start;
		535
		536	$self->{on_connect}
		537	and $self->{on_connect}($self, $host, $port, sub {
		538	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		539	$self->{_skip_drain_rbuf} = 1;
		540	&$retry;
		541	});
		542
		543	} else {
		544	if ($self->{on_connect_error}) {
		545	$self->{on_connect_error}($self, "$!");
		546	$self->destroy if $self;
		547	} else {
		548	$self->_error ($!, 1);
		549	}
		550	}
		551	},
		552	sub {
		553	local $self->{fh} = $_[0];
		554
		555	$self->{on_prepare}
		556	? $self->{on_prepare}->($self)
		557	: ()
		558	}
		559	);
		560	}
		561
		562	} else {
		563	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		564	}
		565
		566	$self
		567	}
		568
		569	sub _start {
		570	my ($self) = @_;
		571
		572	# too many clueless people try to use udp and similar sockets
		573	# with AnyEvent::Handle, do them a favour.
		574	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		575	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		576	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
180		577
181	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	578	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
182		579
183	if ($self->{tls}) {	580	$self->{_activity} =
184	require Net::SSLeay;	581	$self->{_ractivity} =
		582	$self->{_wactivity} = AE::now;
		583
		584	$self->{read_size} ||= 2048;
		585	$self->{max_read_size} = $self->{read_size}
		586	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		587
		588	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		589	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		590	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		591
		592	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		593	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		594
		595	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		596
185	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	597	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
186	}	598	if $self->{tls};
187		599
188	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
189	$self->on_error (delete $self->{on_error}) if $self->{on_error};
190	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	600	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
191	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
192		601
193	$self->start_read;	602	$self->start_read
		603	if $self->{on_read} || @{ $self->{_queue} };
194		604
195	$self	605	$self->_drain_wbuf;
196	}	606	}
197		607
198	sub _shutdown {
199	my ($self) = @_;
200
201	delete $self->{rw};
202	delete $self->{ww};
203	delete $self->{fh};
204	}
205
206	sub error {	608	sub _error {
207	my ($self) = @_;	609	my ($self, $errno, $fatal, $message) = @_;
208		610
209	{	611	$! = $errno;
210	local $!;	612	$message ||= "$!";
211	$self->_shutdown;
212	}
213		613
214	if ($self->{on_error}) {	614	if ($self->{on_error}) {
215	$self->{on_error}($self);	615	$self->{on_error}($self, $fatal, $message);
216	} else {	616	$self->destroy if $fatal;
		617	} elsif ($self->{fh} || $self->{connect}) {
		618	$self->destroy;
217	Carp::croak "AnyEvent::Handle uncaught fatal error: $!";	619	Carp::croak "AnyEvent::Handle uncaught error: $message";
218	}	620	}
219	}	621	}
220		622
221	=item $fh = $handle->fh	623	=item $fh = $handle->fh
222		624
223	This method returns the file handle of the L<AnyEvent::Handle> object.	625	This method returns the file handle used to create the L<AnyEvent::Handle> object.
224		626
225	=cut	627	=cut
226		628
227	sub fh { $_[0]->{fh} }	629	sub fh { $_[0]{fh} }
228		630
229	=item $handle->on_error ($cb)	631	=item $handle->on_error ($cb)
230		632
231	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	633	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
232		634
…		…
244		646
245	sub on_eof {	647	sub on_eof {
246	$_[0]{on_eof} = $_[1];	648	$_[0]{on_eof} = $_[1];
247	}	649	}
248		650
		651	=item $handle->on_timeout ($cb)
		652
		653	=item $handle->on_rtimeout ($cb)
		654
		655	=item $handle->on_wtimeout ($cb)
		656
		657	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		658	callback, or disables the callback (but not the timeout) if C<$cb> =
		659	C<undef>. See the C<timeout> constructor argument and method.
		660
		661	=cut
		662
		663	# see below
		664
		665	=item $handle->autocork ($boolean)
		666
		667	Enables or disables the current autocork behaviour (see C<autocork>
		668	constructor argument). Changes will only take effect on the next write.
		669
		670	=cut
		671
		672	sub autocork {
		673	$_[0]{autocork} = $_[1];
		674	}
		675
		676	=item $handle->no_delay ($boolean)
		677
		678	Enables or disables the C<no_delay> setting (see constructor argument of
		679	the same name for details).
		680
		681	=cut
		682
		683	sub no_delay {
		684	$_[0]{no_delay} = $_[1];
		685
		686	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		687	if $_[0]{fh};
		688	}
		689
		690	=item $handle->keepalive ($boolean)
		691
		692	Enables or disables the C<keepalive> setting (see constructor argument of
		693	the same name for details).
		694
		695	=cut
		696
		697	sub keepalive {
		698	$_[0]{keepalive} = $_[1];
		699
		700	eval {
		701	local $SIG{__DIE__};
		702	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		703	if $_[0]{fh};
		704	};
		705	}
		706
		707	=item $handle->oobinline ($boolean)
		708
		709	Enables or disables the C<oobinline> setting (see constructor argument of
		710	the same name for details).
		711
		712	=cut
		713
		714	sub oobinline {
		715	$_[0]{oobinline} = $_[1];
		716
		717	eval {
		718	local $SIG{__DIE__};
		719	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		720	if $_[0]{fh};
		721	};
		722	}
		723
		724	=item $handle->keepalive ($boolean)
		725
		726	Enables or disables the C<keepalive> setting (see constructor argument of
		727	the same name for details).
		728
		729	=cut
		730
		731	sub keepalive {
		732	$_[0]{keepalive} = $_[1];
		733
		734	eval {
		735	local $SIG{__DIE__};
		736	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		737	if $_[0]{fh};
		738	};
		739	}
		740
		741	=item $handle->on_starttls ($cb)
		742
		743	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		744
		745	=cut
		746
		747	sub on_starttls {
		748	$_[0]{on_starttls} = $_[1];
		749	}
		750
		751	=item $handle->on_stoptls ($cb)
		752
		753	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		754
		755	=cut
		756
		757	sub on_stoptls {
		758	$_[0]{on_stoptls} = $_[1];
		759	}
		760
		761	=item $handle->rbuf_max ($max_octets)
		762
		763	Configures the C<rbuf_max> setting (C<undef> disables it).
		764
		765	=item $handle->wbuf_max ($max_octets)
		766
		767	Configures the C<wbuf_max> setting (C<undef> disables it).
		768
		769	=cut
		770
		771	sub rbuf_max {
		772	$_[0]{rbuf_max} = $_[1];
		773	}
		774
		775	sub wbuf_max {
		776	$_[0]{wbuf_max} = $_[1];
		777	}
		778
		779	#############################################################################
		780
		781	=item $handle->timeout ($seconds)
		782
		783	=item $handle->rtimeout ($seconds)
		784
		785	=item $handle->wtimeout ($seconds)
		786
		787	Configures (or disables) the inactivity timeout.
		788
		789	The timeout will be checked instantly, so this method might destroy the
		790	handle before it returns.
		791
		792	=item $handle->timeout_reset
		793
		794	=item $handle->rtimeout_reset
		795
		796	=item $handle->wtimeout_reset
		797
		798	Reset the activity timeout, as if data was received or sent.
		799
		800	These methods are cheap to call.
		801
		802	=cut
		803
		804	for my $dir ("", "r", "w") {
		805	my $timeout = "${dir}timeout";
		806	my $tw = "_${dir}tw";
		807	my $on_timeout = "on_${dir}timeout";
		808	my $activity = "_${dir}activity";
		809	my $cb;
		810
		811	*$on_timeout = sub {
		812	$_[0]{$on_timeout} = $_[1];
		813	};
		814
		815	*$timeout = sub {
		816	my ($self, $new_value) = @_;
		817
		818	$new_value >= 0
		819	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		820
		821	$self->{$timeout} = $new_value;
		822	delete $self->{$tw}; &$cb;
		823	};
		824
		825	*{"${dir}timeout_reset"} = sub {
		826	$_[0]{$activity} = AE::now;
		827	};
		828
		829	# main workhorse:
		830	# reset the timeout watcher, as neccessary
		831	# also check for time-outs
		832	$cb = sub {
		833	my ($self) = @_;
		834
		835	if ($self->{$timeout} && $self->{fh}) {
		836	my $NOW = AE::now;
		837
		838	# when would the timeout trigger?
		839	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		840
		841	# now or in the past already?
		842	if ($after <= 0) {
		843	$self->{$activity} = $NOW;
		844
		845	if ($self->{$on_timeout}) {
		846	$self->{$on_timeout}($self);
		847	} else {
		848	$self->_error (Errno::ETIMEDOUT);
		849	}
		850
		851	# callback could have changed timeout value, optimise
		852	return unless $self->{$timeout};
		853
		854	# calculate new after
		855	$after = $self->{$timeout};
		856	}
		857
		858	Scalar::Util::weaken $self;
		859	return unless $self; # ->error could have destroyed $self
		860
		861	$self->{$tw} ||= AE::timer $after, 0, sub {
		862	delete $self->{$tw};
		863	$cb->($self);
		864	};
		865	} else {
		866	delete $self->{$tw};
		867	}
		868	}
		869	}
		870
249	#############################################################################	871	#############################################################################
250		872
251	=back	873	=back
252		874
253	=head2 WRITE QUEUE	875	=head2 WRITE QUEUE
…		…
266	=item $handle->on_drain ($cb)	888	=item $handle->on_drain ($cb)
267		889
268	Sets the C<on_drain> callback or clears it (see the description of	890	Sets the C<on_drain> callback or clears it (see the description of
269	C<on_drain> in the constructor).	891	C<on_drain> in the constructor).
270		892
		893	This method may invoke callbacks (and therefore the handle might be
		894	destroyed after it returns).
		895
271	=cut	896	=cut
272		897
273	sub on_drain {	898	sub on_drain {
274	my ($self, $cb) = @_;	899	my ($self, $cb) = @_;
275		900
276	$self->{on_drain} = $cb;	901	$self->{on_drain} = $cb;
277		902
278	$cb->($self)	903	$cb->($self)
279	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	904	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
280	}	905	}
281		906
282	=item $handle->push_write ($data)	907	=item $handle->push_write ($data)
283		908
284	Queues the given scalar to be written. You can push as much data as you	909	Queues the given scalar to be written. You can push as much data as
285	want (only limited by the available memory), as C<AnyEvent::Handle>	910	you want (only limited by the available memory and C<wbuf_max>), as
286	buffers it independently of the kernel.	911	C<AnyEvent::Handle> buffers it independently of the kernel.
		912
		913	This method may invoke callbacks (and therefore the handle might be
		914	destroyed after it returns).
287		915
288	=cut	916	=cut
289		917
290	sub _drain_wbuf {	918	sub _drain_wbuf {
291	my ($self) = @_;	919	my ($self) = @_;
292		920
293	if (!$self->{ww} && length $self->{wbuf}) {	921	if (!$self->{_ww} && length $self->{wbuf}) {
		922
294	Scalar::Util::weaken $self;	923	Scalar::Util::weaken $self;
		924
295	my $cb = sub {	925	my $cb = sub {
296	my $len = syswrite $self->{fh}, $self->{wbuf};	926	my $len = syswrite $self->{fh}, $self->{wbuf};
297		927
298	if ($len >= 0) {	928	if (defined $len) {
299	substr $self->{wbuf}, 0, $len, "";	929	substr $self->{wbuf}, 0, $len, "";
300		930
		931	$self->{_activity} = $self->{_wactivity} = AE::now;
		932
301	$self->{on_drain}($self)	933	$self->{on_drain}($self)
302	if $self->{low_water_mark} >= length $self->{wbuf}	934	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
303	&& $self->{on_drain};	935	&& $self->{on_drain};
304		936
305	delete $self->{ww} unless length $self->{wbuf};	937	delete $self->{_ww} unless length $self->{wbuf};
306	} elsif ($! != EAGAIN && $! != EINTR) {	938	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
307	$self->error;	939	$self->_error ($!, 1);
308	}	940	}
309	};	941	};
310		942
311	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	943	# try to write data immediately
		944	$cb->() unless $self->{autocork};
312		945
313	$cb->($self);	946	# if still data left in wbuf, we need to poll
		947	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		948	if length $self->{wbuf};
		949
		950	if (
		951	defined $self->{wbuf_max}
		952	&& $self->{wbuf_max} < length $self->{wbuf}
		953	) {
		954	$self->_error (Errno::ENOSPC, 1), return;
		955	}
314	};	956	};
315	}	957	}
316		958
317	our %WH;	959	our %WH;
318		960
		961	# deprecated
319	sub register_write_type($$) {	962	sub register_write_type($$) {
320	$WH{$_[0]} = $_[1];	963	$WH{$_[0]} = $_[1];
321	}	964	}
322		965
323	sub push_write {	966	sub push_write {
324	my $self = shift;	967	my $self = shift;
325		968
326	if (@_ > 1) {	969	if (@_ > 1) {
327	my $type = shift;	970	my $type = shift;
328		971
		972	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
329	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	973	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
330	->($self, @_);	974	->($self, @_);
331	}	975	}
332		976
		977	# we downgrade here to avoid hard-to-track-down bugs,
		978	# and diagnose the problem earlier and better.
		979
333	if ($self->{filter_w}) {	980	if ($self->{tls}) {
334	$self->{filter_w}->($self, \$_[0]);	981	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		982	&_dotls ($self) if $self->{fh};
335	} else {	983	} else {
336	$self->{wbuf} .= $_[0];	984	utf8::downgrade $self->{wbuf} .= $_[0];
337	$self->_drain_wbuf;	985	$self->_drain_wbuf if $self->{fh};
338	}	986	}
339	}	987	}
340		988
341	=item $handle->push_write (type => @args)	989	=item $handle->push_write (type => @args)
342		990
343	=item $handle->unshift_write (type => @args)
344
345	Instead of formatting your data yourself, you can also let this module do	991	Instead of formatting your data yourself, you can also let this module
346	the job by specifying a type and type-specific arguments.	992	do the job by specifying a type and type-specific arguments. You
		993	can also specify the (fully qualified) name of a package, in which
		994	case AnyEvent tries to load the package and then expects to find the
		995	C<anyevent_write_type> function inside (see "custom write types", below).
347		996
348	Predefined types are (if you have ideas for additional types, feel free to	997	Predefined types are (if you have ideas for additional types, feel free to
349	drop by and tell us):	998	drop by and tell us):
350		999
351	=over 4	1000	=over 4
…		…
353	=item netstring => $string	1002	=item netstring => $string
354		1003
355	Formats the given value as netstring	1004	Formats the given value as netstring
356	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).	1005	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
357		1006
358	=back
359
360	=cut	1007	=cut
361		1008
362	register_write_type netstring => sub {	1009	register_write_type netstring => sub {
363	my ($self, $string) = @_;	1010	my ($self, $string) = @_;
364		1011
365	sprintf "%d:%s,", (length $string), $string	1012	(length $string) . ":$string,"
366	};	1013	};
367		1014
368	=item AnyEvent::Handle::register_write_type type => $coderef->($self, @args)	1015	=item packstring => $format, $data
369		1016
370	This function (not method) lets you add your own types to C<push_write>.	1017	An octet string prefixed with an encoded length. The encoding C<$format>
		1018	uses the same format as a Perl C<pack> format, but must specify a single
		1019	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1020	optional C<!>, C<< < >> or C<< > >> modifier).
		1021
		1022	=cut
		1023
		1024	register_write_type packstring => sub {
		1025	my ($self, $format, $string) = @_;
		1026
		1027	pack "$format/a*", $string
		1028	};
		1029
		1030	=item json => $array_or_hashref
		1031
		1032	Encodes the given hash or array reference into a JSON object. Unless you
		1033	provide your own JSON object, this means it will be encoded to JSON text
		1034	in UTF-8.
		1035
		1036	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		1037	one end of a handle and read them at the other end without using any
		1038	additional framing.
		1039
		1040	The generated JSON text is guaranteed not to contain any newlines: While
		1041	this module doesn't need delimiters after or between JSON texts to be
		1042	able to read them, many other languages depend on that.
		1043
		1044	A simple RPC protocol that interoperates easily with others is to send
		1045	JSON arrays (or objects, although arrays are usually the better choice as
		1046	they mimic how function argument passing works) and a newline after each
		1047	JSON text:
		1048
		1049	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		1050	$handle->push_write ("\012");
		1051
		1052	An AnyEvent::Handle receiver would simply use the C<json> read type and
		1053	rely on the fact that the newline will be skipped as leading whitespace:
		1054
		1055	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1056
		1057	Other languages could read single lines terminated by a newline and pass
		1058	this line into their JSON decoder of choice.
		1059
		1060	=cut
		1061
		1062	sub json_coder() {
		1063	eval { require JSON::XS; JSON::XS->new->utf8 }
		1064	|| do { require JSON; JSON->new->utf8 }
		1065	}
		1066
		1067	register_write_type json => sub {
		1068	my ($self, $ref) = @_;
		1069
		1070	my $json = $self->{json} ||= json_coder;
		1071
		1072	$json->encode ($ref)
		1073	};
		1074
		1075	=item storable => $reference
		1076
		1077	Freezes the given reference using L<Storable> and writes it to the
		1078	handle. Uses the C<nfreeze> format.
		1079
		1080	=cut
		1081
		1082	register_write_type storable => sub {
		1083	my ($self, $ref) = @_;
		1084
		1085	require Storable;
		1086
		1087	pack "w/a*", Storable::nfreeze ($ref)
		1088	};
		1089
		1090	=back
		1091
		1092	=item $handle->push_shutdown
		1093
		1094	Sometimes you know you want to close the socket after writing your data
		1095	before it was actually written. One way to do that is to replace your
		1096	C<on_drain> handler by a callback that shuts down the socket (and set
		1097	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1098	replaces the C<on_drain> callback with:
		1099
		1100	sub { shutdown $_[0]{fh}, 1 }
		1101
		1102	This simply shuts down the write side and signals an EOF condition to the
		1103	the peer.
		1104
		1105	You can rely on the normal read queue and C<on_eof> handling
		1106	afterwards. This is the cleanest way to close a connection.
		1107
		1108	This method may invoke callbacks (and therefore the handle might be
		1109	destroyed after it returns).
		1110
		1111	=cut
		1112
		1113	sub push_shutdown {
		1114	my ($self) = @_;
		1115
		1116	delete $self->{low_water_mark};
		1117	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1118	}
		1119
		1120	=item custom write types - Package::anyevent_write_type $handle, @args
		1121
		1122	Instead of one of the predefined types, you can also specify the name of
		1123	a package. AnyEvent will try to load the package and then expects to find
		1124	a function named C<anyevent_write_type> inside. If it isn't found, it
		1125	progressively tries to load the parent package until it either finds the
		1126	function (good) or runs out of packages (bad).
		1127
371	Whenever the given C<type> is used, C<push_write> will invoke the code	1128	Whenever the given C<type> is used, C<push_write> will the function with
372	reference with the handle object and the remaining arguments.	1129	the handle object and the remaining arguments.
373		1130
374	The code reference is supposed to return a single octet string that will	1131	The function is supposed to return a single octet string that will be
375	be appended to the write buffer.	1132	appended to the write buffer, so you cna mentally treat this function as a
		1133	"arguments to on-the-wire-format" converter.
376		1134
377	Note that this is a function, and all types registered this way will be	1135	Example: implement a custom write type C<join> that joins the remaining
378	global, so try to use unique names.	1136	arguments using the first one.
		1137
		1138	$handle->push_write (My::Type => " ", 1,2,3);
		1139
		1140	# uses the following package, which can be defined in the "My::Type" or in
		1141	# the "My" modules to be auto-loaded, or just about anywhere when the
		1142	# My::Type::anyevent_write_type is defined before invoking it.
		1143
		1144	package My::Type;
		1145
		1146	sub anyevent_write_type {
		1147	my ($handle, $delim, @args) = @_;
		1148
		1149	join $delim, @args
		1150	}
379		1151
380	=cut	1152	=cut
381		1153
382	#############################################################################	1154	#############################################################################
383		1155
…		…
392	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1164	ways, the "simple" way, using only C<on_read> and the "complex" way, using
393	a queue.	1165	a queue.
394		1166
395	In the simple case, you just install an C<on_read> callback and whenever	1167	In the simple case, you just install an C<on_read> callback and whenever
396	new data arrives, it will be called. You can then remove some data (if	1168	new data arrives, it will be called. You can then remove some data (if
397	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1169	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
398	or not.	1170	leave the data there if you want to accumulate more (e.g. when only a
		1171	partial message has been received so far), or change the read queue with
		1172	e.g. C<push_read>.
399		1173
400	In the more complex case, you want to queue multiple callbacks. In this	1174	In the more complex case, you want to queue multiple callbacks. In this
401	case, AnyEvent::Handle will call the first queued callback each time new	1175	case, AnyEvent::Handle will call the first queued callback each time new
402	data arrives and removes it when it has done its job (see C<push_read>,	1176	data arrives (also the first time it is queued) and remove it when it has
403	below).	1177	done its job (see C<push_read>, below).
404		1178
405	This way you can, for example, push three line-reads, followed by reading	1179	This way you can, for example, push three line-reads, followed by reading
406	a chunk of data, and AnyEvent::Handle will execute them in order.	1180	a chunk of data, and AnyEvent::Handle will execute them in order.
407		1181
408	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1182	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
409	the specified number of bytes which give an XML datagram.	1183	the specified number of bytes which give an XML datagram.
410		1184
411	# in the default state, expect some header bytes	1185	# in the default state, expect some header bytes
412	$handle->on_read (sub {	1186	$handle->on_read (sub {
413	# some data is here, now queue the length-header-read (4 octets)	1187	# some data is here, now queue the length-header-read (4 octets)
414	shift->unshift_read_chunk (4, sub {	1188	shift->unshift_read (chunk => 4, sub {
415	# header arrived, decode	1189	# header arrived, decode
416	my $len = unpack "N", $_[1];	1190	my $len = unpack "N", $_[1];
417		1191
418	# now read the payload	1192	# now read the payload
419	shift->unshift_read_chunk ($len, sub {	1193	shift->unshift_read (chunk => $len, sub {
420	my $xml = $_[1];	1194	my $xml = $_[1];
421	# handle xml	1195	# handle xml
422	});	1196	});
423	});	1197	});
424	});	1198	});
425		1199
426	Example 2: Implement a client for a protocol that replies either with	1200	Example 2: Implement a client for a protocol that replies either with "OK"
427	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1201	and another line or "ERROR" for the first request that is sent, and 64
428	second request. Due tot he availability of a full queue, we can just	1202	bytes for the second request. Due to the availability of a queue, we can
429	pipeline sending both requests and manipulate the queue as necessary in	1203	just pipeline sending both requests and manipulate the queue as necessary
430	the callbacks:	1204	in the callbacks.
431		1205
432	# request one	1206	When the first callback is called and sees an "OK" response, it will
		1207	C<unshift> another line-read. This line-read will be queued I<before> the
		1208	64-byte chunk callback.
		1209
		1210	# request one, returns either "OK + extra line" or "ERROR"
433	$handle->push_write ("request 1\015\012");	1211	$handle->push_write ("request 1\015\012");
434		1212
435	# we expect "ERROR" or "OK" as response, so push a line read	1213	# we expect "ERROR" or "OK" as response, so push a line read
436	$handle->push_read_line (sub {	1214	$handle->push_read (line => sub {
437	# if we got an "OK", we have to _prepend_ another line,	1215	# if we got an "OK", we have to _prepend_ another line,
438	# so it will be read before the second request reads its 64 bytes	1216	# so it will be read before the second request reads its 64 bytes
439	# which are already in the queue when this callback is called	1217	# which are already in the queue when this callback is called
440	# we don't do this in case we got an error	1218	# we don't do this in case we got an error
441	if ($_[1] eq "OK") {	1219	if ($_[1] eq "OK") {
442	$_[0]->unshift_read_line (sub {	1220	$_[0]->unshift_read (line => sub {
443	my $response = $_[1];	1221	my $response = $_[1];
444	...	1222	...
445	});	1223	});
446	}	1224	}
447	});	1225	});
448		1226
449	# request two	1227	# request two, simply returns 64 octets
450	$handle->push_write ("request 2\015\012");	1228	$handle->push_write ("request 2\015\012");
451		1229
452	# simply read 64 bytes, always	1230	# simply read 64 bytes, always
453	$handle->push_read_chunk (64, sub {	1231	$handle->push_read (chunk => 64, sub {
454	my $response = $_[1];	1232	my $response = $_[1];
455	...	1233	...
456	});	1234	});
457		1235
458	=over 4	1236	=over 4
459		1237
460	=cut	1238	=cut
461		1239
462	sub _drain_rbuf {	1240	sub _drain_rbuf {
463	my ($self) = @_;	1241	my ($self) = @_;
		1242
		1243	# avoid recursion
		1244	return if $self->{_skip_drain_rbuf};
		1245	local $self->{_skip_drain_rbuf} = 1;
		1246
		1247	while () {
		1248	# we need to use a separate tls read buffer, as we must not receive data while
		1249	# we are draining the buffer, and this can only happen with TLS.
		1250	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1251	if exists $self->{_tls_rbuf};
		1252
		1253	my $len = length $self->{rbuf};
		1254
		1255	if (my $cb = shift @{ $self->{_queue} }) {
		1256	unless ($cb->($self)) {
		1257	# no progress can be made
		1258	# (not enough data and no data forthcoming)
		1259	$self->_error (Errno::EPIPE, 1), return
		1260	if $self->{_eof};
		1261
		1262	unshift @{ $self->{_queue} }, $cb;
		1263	last;
		1264	}
		1265	} elsif ($self->{on_read}) {
		1266	last unless $len;
		1267
		1268	$self->{on_read}($self);
		1269
		1270	if (
		1271	$len == length $self->{rbuf} # if no data has been consumed
		1272	&& !@{ $self->{_queue} } # and the queue is still empty
		1273	&& $self->{on_read} # but we still have on_read
		1274	) {
		1275	# no further data will arrive
		1276	# so no progress can be made
		1277	$self->_error (Errno::EPIPE, 1), return
		1278	if $self->{_eof};
		1279
		1280	last; # more data might arrive
		1281	}
		1282	} else {
		1283	# read side becomes idle
		1284	delete $self->{_rw} unless $self->{tls};
		1285	last;
		1286	}
		1287	}
		1288
		1289	if ($self->{_eof}) {
		1290	$self->{on_eof}
		1291	? $self->{on_eof}($self)
		1292	: $self->_error (0, 1, "Unexpected end-of-file");
		1293
		1294	return;
		1295	}
464		1296
465	if (	1297	if (
466	defined $self->{rbuf_max}	1298	defined $self->{rbuf_max}
467	&& $self->{rbuf_max} < length $self->{rbuf}	1299	&& $self->{rbuf_max} < length $self->{rbuf}
468	) {	1300	) {
469	$! = &Errno::ENOSPC; return $self->error;	1301	$self->_error (Errno::ENOSPC, 1), return;
470	}	1302	}
471		1303
472	return if $self->{in_drain};	1304	# may need to restart read watcher
473	local $self->{in_drain} = 1;	1305	unless ($self->{_rw}) {
474		1306	$self->start_read
475	while (my $len = length $self->{rbuf}) {	1307	if $self->{on_read} || @{ $self->{_queue} };
476	no strict 'refs';
477	if (my $cb = shift @{ $self->{queue} }) {
478	unless ($cb->($self)) {
479	if ($self->{eof}) {
480	# no progress can be made (not enough data and no data forthcoming)
481	$! = &Errno::EPIPE; return $self->error;
482	}
483
484	unshift @{ $self->{queue} }, $cb;
485	return;
486	}
487	} elsif ($self->{on_read}) {
488	$self->{on_read}($self);
489
490	if (
491	$self->{eof} # if no further data will arrive
492	&& $len == length $self->{rbuf} # and no data has been consumed
493	&& !@{ $self->{queue} } # and the queue is still empty
494	&& $self->{on_read} # and we still want to read data
495	) {
496	# then no progress can be made
497	$! = &Errno::EPIPE; return $self->error;
498	}
499	} else {
500	# read side becomes idle
501	delete $self->{rw};
502	return;
503	}
504	}
505
506	if ($self->{eof}) {
507	$self->_shutdown;
508	$self->{on_eof}($self)
509	if $self->{on_eof};
510	}	1308	}
511	}	1309	}
512		1310
513	=item $handle->on_read ($cb)	1311	=item $handle->on_read ($cb)
514		1312
515	This replaces the currently set C<on_read> callback, or clears it (when	1313	This replaces the currently set C<on_read> callback, or clears it (when
516	the new callback is C<undef>). See the description of C<on_read> in the	1314	the new callback is C<undef>). See the description of C<on_read> in the
517	constructor.	1315	constructor.
518		1316
		1317	This method may invoke callbacks (and therefore the handle might be
		1318	destroyed after it returns).
		1319
519	=cut	1320	=cut
520		1321
521	sub on_read {	1322	sub on_read {
522	my ($self, $cb) = @_;	1323	my ($self, $cb) = @_;
523		1324
524	$self->{on_read} = $cb;	1325	$self->{on_read} = $cb;
		1326	$self->_drain_rbuf if $cb;
525	}	1327	}
526		1328
527	=item $handle->rbuf	1329	=item $handle->rbuf
528		1330
529	Returns the read buffer (as a modifiable lvalue).	1331	Returns the read buffer (as a modifiable lvalue). You can also access the
		1332	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1333	much faster, and no less clean).
530		1334
531	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1335	The only operation allowed on the read buffer (apart from looking at it)
532	you want.	1336	is removing data from its beginning. Otherwise modifying or appending to
		1337	it is not allowed and will lead to hard-to-track-down bugs.
533		1338
534	NOTE: The read buffer should only be used or modified if the C<on_read>,	1339	NOTE: The read buffer should only be used or modified in the C<on_read>
535	C<push_read> or C<unshift_read> methods are used. The other read methods	1340	callback or when C<push_read> or C<unshift_read> are used with a single
536	automatically manage the read buffer.	1341	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1342	will manage the read buffer on their own.
537		1343
538	=cut	1344	=cut
539		1345
540	sub rbuf : lvalue {	1346	sub rbuf : lvalue {
541	$_[0]{rbuf}	1347	$_[0]{rbuf}
…		…
558		1364
559	If enough data was available, then the callback must remove all data it is	1365	If enough data was available, then the callback must remove all data it is
560	interested in (which can be none at all) and return a true value. After returning	1366	interested in (which can be none at all) and return a true value. After returning
561	true, it will be removed from the queue.	1367	true, it will be removed from the queue.
562		1368
		1369	These methods may invoke callbacks (and therefore the handle might be
		1370	destroyed after it returns).
		1371
563	=cut	1372	=cut
564		1373
565	our %RH;	1374	our %RH;
566		1375
567	sub register_read_type($$) {	1376	sub register_read_type($$) {
…		…
573	my $cb = pop;	1382	my $cb = pop;
574		1383
575	if (@_) {	1384	if (@_) {
576	my $type = shift;	1385	my $type = shift;
577		1386
		1387	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
578	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	1388	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
579	->($self, $cb, @_);	1389	->($self, $cb, @_);
580	}	1390	}
581		1391
582	push @{ $self->{queue} }, $cb;	1392	push @{ $self->{_queue} }, $cb;
583	$self->_drain_rbuf;	1393	$self->_drain_rbuf;
584	}	1394	}
585		1395
586	sub unshift_read {	1396	sub unshift_read {
587	my $self = shift;	1397	my $self = shift;
588	my $cb = pop;	1398	my $cb = pop;
589		1399
590	if (@_) {	1400	if (@_) {
591	my $type = shift;	1401	my $type = shift;
592		1402
		1403	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
593	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")	1404	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
594	->($self, $cb, @_);	1405	->($self, $cb, @_);
595	}	1406	}
596		1407
597
598	unshift @{ $self->{queue} }, $cb;	1408	unshift @{ $self->{_queue} }, $cb;
599	$self->_drain_rbuf;	1409	$self->_drain_rbuf;
600	}	1410	}
601		1411
602	=item $handle->push_read (type => @args, $cb)	1412	=item $handle->push_read (type => @args, $cb)
603		1413
604	=item $handle->unshift_read (type => @args, $cb)	1414	=item $handle->unshift_read (type => @args, $cb)
605		1415
606	Instead of providing a callback that parses the data itself you can chose	1416	Instead of providing a callback that parses the data itself you can chose
607	between a number of predefined parsing formats, for chunks of data, lines	1417	between a number of predefined parsing formats, for chunks of data, lines
608	etc.	1418	etc. You can also specify the (fully qualified) name of a package, in
		1419	which case AnyEvent tries to load the package and then expects to find the
		1420	C<anyevent_read_type> function inside (see "custom read types", below).
609		1421
610	Predefined types are (if you have ideas for additional types, feel free to	1422	Predefined types are (if you have ideas for additional types, feel free to
611	drop by and tell us):	1423	drop by and tell us):
612		1424
613	=over 4	1425	=over 4
614		1426
615	=item chunk => $octets, $cb->($self, $data)	1427	=item chunk => $octets, $cb->($handle, $data)
616		1428
617	Invoke the callback only once C<$octets> bytes have been read. Pass the	1429	Invoke the callback only once C<$octets> bytes have been read. Pass the
618	data read to the callback. The callback will never be called with less	1430	data read to the callback. The callback will never be called with less
619	data.	1431	data.
620		1432
…		…
634	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1446	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
635	1	1447	1
636	}	1448	}
637	};	1449	};
638		1450
639	# compatibility with older API
640	sub push_read_chunk {
641	$_[0]->push_read (chunk => $_[1], $_[2]);
642	}
643
644	sub unshift_read_chunk {
645	$_[0]->unshift_read (chunk => $_[1], $_[2]);
646	}
647
648	=item line => [$eol, ]$cb->($self, $line, $eol)	1451	=item line => [$eol, ]$cb->($handle, $line, $eol)
649		1452
650	The callback will be called only once a full line (including the end of	1453	The callback will be called only once a full line (including the end of
651	line marker, C<$eol>) has been read. This line (excluding the end of line	1454	line marker, C<$eol>) has been read. This line (excluding the end of line
652	marker) will be passed to the callback as second argument (C<$line>), and	1455	marker) will be passed to the callback as second argument (C<$line>), and
653	the end of line marker as the third argument (C<$eol>).	1456	the end of line marker as the third argument (C<$eol>).
…		…
667	=cut	1470	=cut
668		1471
669	register_read_type line => sub {	1472	register_read_type line => sub {
670	my ($self, $cb, $eol) = @_;	1473	my ($self, $cb, $eol) = @_;
671		1474
672	$eol = qr|(\015?\012)| if @_ < 3;	1475	if (@_ < 3) {
		1476	# this is more than twice as fast as the generic code below
		1477	sub {
		1478	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1479
		1480	$cb->($_[0], $1, $2);
		1481	1
		1482	}
		1483	} else {
673	$eol = quotemeta $eol unless ref $eol;	1484	$eol = quotemeta $eol unless ref $eol;
674	$eol = qr|^(.*?)($eol)|s;	1485	$eol = qr|^(.*?)($eol)|s;
		1486
		1487	sub {
		1488	$_[0]{rbuf} =~ s/$eol// or return;
		1489
		1490	$cb->($_[0], $1, $2);
		1491	1
		1492	}
		1493	}
		1494	};
		1495
		1496	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1497
		1498	Makes a regex match against the regex object C<$accept> and returns
		1499	everything up to and including the match.
		1500
		1501	Example: read a single line terminated by '\n'.
		1502
		1503	$handle->push_read (regex => qr<\n>, sub { ... });
		1504
		1505	If C<$reject> is given and not undef, then it determines when the data is
		1506	to be rejected: it is matched against the data when the C<$accept> regex
		1507	does not match and generates an C<EBADMSG> error when it matches. This is
		1508	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1509	receive buffer overflow).
		1510
		1511	Example: expect a single decimal number followed by whitespace, reject
		1512	anything else (not the use of an anchor).
		1513
		1514	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1515
		1516	If C<$skip> is given and not C<undef>, then it will be matched against
		1517	the receive buffer when neither C<$accept> nor C<$reject> match,
		1518	and everything preceding and including the match will be accepted
		1519	unconditionally. This is useful to skip large amounts of data that you
		1520	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1521	have to start matching from the beginning. This is purely an optimisation
		1522	and is usually worth it only when you expect more than a few kilobytes.
		1523
		1524	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1525	expect the header to be very large (it isn't in practice, but...), we use
		1526	a skip regex to skip initial portions. The skip regex is tricky in that
		1527	it only accepts something not ending in either \015 or \012, as these are
		1528	required for the accept regex.
		1529
		1530	$handle->push_read (regex =>
		1531	qr<\015\012\015\012>,
		1532	undef, # no reject
		1533	qr<^.*[^\015\012]>,
		1534	sub { ... });
		1535
		1536	=cut
		1537
		1538	register_read_type regex => sub {
		1539	my ($self, $cb, $accept, $reject, $skip) = @_;
		1540
		1541	my $data;
		1542	my $rbuf = \$self->{rbuf};
675		1543
676	sub {	1544	sub {
677	$_[0]{rbuf} =~ s/$eol// or return;	1545	# accept
678		1546	if ($$rbuf =~ $accept) {
679	$cb->($_[0], $1, $2);	1547	$data .= substr $$rbuf, 0, $+[0], "";
		1548	$cb->($self, $data);
		1549	return 1;
		1550	}
680	1	1551
		1552	# reject
		1553	if ($reject && $$rbuf =~ $reject) {
		1554	$self->_error (Errno::EBADMSG);
		1555	}
		1556
		1557	# skip
		1558	if ($skip && $$rbuf =~ $skip) {
		1559	$data .= substr $$rbuf, 0, $+[0], "";
		1560	}
		1561
		1562	()
681	}	1563	}
682	};	1564	};
683		1565
684	# compatibility with older API
685	sub push_read_line {
686	my $self = shift;
687	$self->push_read (line => @_);
688	}
689
690	sub unshift_read_line {
691	my $self = shift;
692	$self->unshift_read (line => @_);
693	}
694
695	=item netstring => $cb->($string)	1566	=item netstring => $cb->($handle, $string)
696		1567
697	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).	1568	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
698		1569
699	Throws an error with C<$!> set to EBADMSG on format violations.	1570	Throws an error with C<$!> set to EBADMSG on format violations.
700		1571
…		…
704	my ($self, $cb) = @_;	1575	my ($self, $cb) = @_;
705		1576
706	sub {	1577	sub {
707	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {	1578	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
708	if ($_[0]{rbuf} =~ /[^0-9]/) {	1579	if ($_[0]{rbuf} =~ /[^0-9]/) {
709	$! = &Errno::EBADMSG;	1580	$self->_error (Errno::EBADMSG);
710	$self->error;
711	}	1581	}
712	return;	1582	return;
713	}	1583	}
714		1584
715	my $len = $1;	1585	my $len = $1;
…		…
718	my $string = $_[1];	1588	my $string = $_[1];
719	$_[0]->unshift_read (chunk => 1, sub {	1589	$_[0]->unshift_read (chunk => 1, sub {
720	if ($_[1] eq ",") {	1590	if ($_[1] eq ",") {
721	$cb->($_[0], $string);	1591	$cb->($_[0], $string);
722	} else {	1592	} else {
723	$! = &Errno::EBADMSG;
724	$self->error;	1593	$self->_error (Errno::EBADMSG);
725	}	1594	}
726	});	1595	});
727	});	1596	});
728		1597
729	1	1598	1
730	}	1599	}
731	};	1600	};
732		1601
		1602	=item packstring => $format, $cb->($handle, $string)
		1603
		1604	An octet string prefixed with an encoded length. The encoding C<$format>
		1605	uses the same format as a Perl C<pack> format, but must specify a single
		1606	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1607	optional C<!>, C<< < >> or C<< > >> modifier).
		1608
		1609	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1610	EPP uses a prefix of C<N> (4 octtes).
		1611
		1612	Example: read a block of data prefixed by its length in BER-encoded
		1613	format (very efficient).
		1614
		1615	$handle->push_read (packstring => "w", sub {
		1616	my ($handle, $data) = @_;
		1617	});
		1618
		1619	=cut
		1620
		1621	register_read_type packstring => sub {
		1622	my ($self, $cb, $format) = @_;
		1623
		1624	sub {
		1625	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1626	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1627	or return;
		1628
		1629	$format = length pack $format, $len;
		1630
		1631	# bypass unshift if we already have the remaining chunk
		1632	if ($format + $len <= length $_[0]{rbuf}) {
		1633	my $data = substr $_[0]{rbuf}, $format, $len;
		1634	substr $_[0]{rbuf}, 0, $format + $len, "";
		1635	$cb->($_[0], $data);
		1636	} else {
		1637	# remove prefix
		1638	substr $_[0]{rbuf}, 0, $format, "";
		1639
		1640	# read remaining chunk
		1641	$_[0]->unshift_read (chunk => $len, $cb);
		1642	}
		1643
		1644	1
		1645	}
		1646	};
		1647
		1648	=item json => $cb->($handle, $hash_or_arrayref)
		1649
		1650	Reads a JSON object or array, decodes it and passes it to the
		1651	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1652
		1653	If a C<json> object was passed to the constructor, then that will be used
		1654	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1655
		1656	This read type uses the incremental parser available with JSON version
		1657	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1658	dependency on your own: this module will load the JSON module, but
		1659	AnyEvent does not depend on it itself.
		1660
		1661	Since JSON texts are fully self-delimiting, the C<json> read and write
		1662	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1663	the C<json> write type description, above, for an actual example.
		1664
		1665	=cut
		1666
		1667	register_read_type json => sub {
		1668	my ($self, $cb) = @_;
		1669
		1670	my $json = $self->{json} ||= json_coder;
		1671
		1672	my $data;
		1673	my $rbuf = \$self->{rbuf};
		1674
		1675	sub {
		1676	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1677
		1678	if ($ref) {
		1679	$self->{rbuf} = $json->incr_text;
		1680	$json->incr_text = "";
		1681	$cb->($self, $ref);
		1682
		1683	1
		1684	} elsif ($@) {
		1685	# error case
		1686	$json->incr_skip;
		1687
		1688	$self->{rbuf} = $json->incr_text;
		1689	$json->incr_text = "";
		1690
		1691	$self->_error (Errno::EBADMSG);
		1692
		1693	()
		1694	} else {
		1695	$self->{rbuf} = "";
		1696
		1697	()
		1698	}
		1699	}
		1700	};
		1701
		1702	=item storable => $cb->($handle, $ref)
		1703
		1704	Deserialises a L<Storable> frozen representation as written by the
		1705	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1706	data).
		1707
		1708	Raises C<EBADMSG> error if the data could not be decoded.
		1709
		1710	=cut
		1711
		1712	register_read_type storable => sub {
		1713	my ($self, $cb) = @_;
		1714
		1715	require Storable;
		1716
		1717	sub {
		1718	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1719	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1720	or return;
		1721
		1722	my $format = length pack "w", $len;
		1723
		1724	# bypass unshift if we already have the remaining chunk
		1725	if ($format + $len <= length $_[0]{rbuf}) {
		1726	my $data = substr $_[0]{rbuf}, $format, $len;
		1727	substr $_[0]{rbuf}, 0, $format + $len, "";
		1728	$cb->($_[0], Storable::thaw ($data));
		1729	} else {
		1730	# remove prefix
		1731	substr $_[0]{rbuf}, 0, $format, "";
		1732
		1733	# read remaining chunk
		1734	$_[0]->unshift_read (chunk => $len, sub {
		1735	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1736	$cb->($_[0], $ref);
		1737	} else {
		1738	$self->_error (Errno::EBADMSG);
		1739	}
		1740	});
		1741	}
		1742
		1743	1
		1744	}
		1745	};
		1746
733	=back	1747	=back
734		1748
735	=item AnyEvent::Handle::register_read_type type => $coderef->($self, $cb, @args)	1749	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
736		1750
737	This function (not method) lets you add your own types to C<push_read>.	1751	Instead of one of the predefined types, you can also specify the name
		1752	of a package. AnyEvent will try to load the package and then expects to
		1753	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1754	progressively tries to load the parent package until it either finds the
		1755	function (good) or runs out of packages (bad).
738		1756
739	Whenever the given C<type> is used, C<push_read> will invoke the code	1757	Whenever this type is used, C<push_read> will invoke the function with the
740	reference with the handle object, the callback and the remaining	1758	handle object, the original callback and the remaining arguments.
741	arguments.
742		1759
743	The code reference is supposed to return a callback (usually a closure)	1760	The function is supposed to return a callback (usually a closure) that
744	that works as a plain read callback (see C<< ->push_read ($cb) >>).	1761	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1762	mentally treat the function as a "configurable read type to read callback"
		1763	converter.
745		1764
746	It should invoke the passed callback when it is done reading (remember to	1765	It should invoke the original callback when it is done reading (remember
747	pass C<$self> as first argument as all other callbacks do that).	1766	to pass C<$handle> as first argument as all other callbacks do that,
		1767	although there is no strict requirement on this).
748		1768
749	Note that this is a function, and all types registered this way will be
750	global, so try to use unique names.
751
752	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,	1769	For examples, see the source of this module (F<perldoc -m
753	search for C<register_read_type>)).	1770	AnyEvent::Handle>, search for C<register_read_type>)).
754		1771
755	=item $handle->stop_read	1772	=item $handle->stop_read
756		1773
757	=item $handle->start_read	1774	=item $handle->start_read
758		1775
759	In rare cases you actually do not want to read anything from the	1776	In rare cases you actually do not want to read anything from the
760	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1777	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
761	any queued callbacks will be executed then. To start reading again, call	1778	any queued callbacks will be executed then. To start reading again, call
762	C<start_read>.	1779	C<start_read>.
763		1780
		1781	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1782	you change the C<on_read> callback or push/unshift a read callback, and it
		1783	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1784	there are any read requests in the queue.
		1785
		1786	In older versions of this module (<= 5.3), these methods had no effect,
		1787	as TLS does not support half-duplex connections. In current versions they
		1788	work as expected, as this behaviour is required to avoid certain resource
		1789	attacks, where the program would be forced to read (and buffer) arbitrary
		1790	amounts of data before being able to send some data. The drawback is that
		1791	some readings of the the SSL/TLS specifications basically require this
		1792	attack to be working, as SSL/TLS implementations might stall sending data
		1793	during a rehandshake.
		1794
		1795	As a guideline, during the initial handshake, you should not stop reading,
		1796	and as a client, it might cause problems, depending on your applciation.
		1797
764	=cut	1798	=cut
765		1799
766	sub stop_read {	1800	sub stop_read {
767	my ($self) = @_;	1801	my ($self) = @_;
768		1802
769	delete $self->{rw};	1803	delete $self->{_rw};
770	}	1804	}
771		1805
772	sub start_read {	1806	sub start_read {
773	my ($self) = @_;	1807	my ($self) = @_;
774		1808
775	unless ($self->{rw} || $self->{eof}) {	1809	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
776	Scalar::Util::weaken $self;	1810	Scalar::Util::weaken $self;
777		1811
778	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1812	$self->{_rw} = AE::io $self->{fh}, 0, sub {
779	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1813	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
780	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1814	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
781		1815
782	if ($len > 0) {	1816	if ($len > 0) {
783	$self->{filter_r}	1817	$self->{_activity} = $self->{_ractivity} = AE::now;
784	? $self->{filter_r}->($self, $rbuf)	1818
		1819	if ($self->{tls}) {
		1820	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1821
		1822	&_dotls ($self);
		1823	} else {
785	: $self->_drain_rbuf;	1824	$self->_drain_rbuf;
		1825	}
		1826
		1827	if ($len == $self->{read_size}) {
		1828	$self->{read_size} *= 2;
		1829	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		1830	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		1831	}
786		1832
787	} elsif (defined $len) {	1833	} elsif (defined $len) {
788	delete $self->{rw};	1834	delete $self->{_rw};
789	$self->{eof} = 1;	1835	$self->{_eof} = 1;
790	$self->_drain_rbuf;	1836	$self->_drain_rbuf;
791		1837
792	} elsif ($! != EAGAIN && $! != EINTR) {	1838	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
793	return $self->error;	1839	return $self->_error ($!, 1);
794	}	1840	}
795	});	1841	};
796	}	1842	}
797	}	1843	}
798		1844
		1845	our $ERROR_SYSCALL;
		1846	our $ERROR_WANT_READ;
		1847
		1848	sub _tls_error {
		1849	my ($self, $err) = @_;
		1850
		1851	return $self->_error ($!, 1)
		1852	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1853
		1854	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1855
		1856	# reduce error string to look less scary
		1857	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1858
		1859	if ($self->{_on_starttls}) {
		1860	(delete $self->{_on_starttls})->($self, undef, $err);
		1861	&_freetls;
		1862	} else {
		1863	&_freetls;
		1864	$self->_error (Errno::EPROTO, 1, $err);
		1865	}
		1866	}
		1867
		1868	# poll the write BIO and send the data if applicable
		1869	# also decode read data if possible
		1870	# this is basiclaly our TLS state machine
		1871	# more efficient implementations are possible with openssl,
		1872	# but not with the buggy and incomplete Net::SSLeay.
799	sub _dotls {	1873	sub _dotls {
800	my ($self) = @_;	1874	my ($self) = @_;
801		1875
		1876	my $tmp;
		1877
802	if (length $self->{tls_wbuf}) {	1878	if (length $self->{_tls_wbuf}) {
803	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{tls_wbuf})) > 0) {	1879	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
804	substr $self->{tls_wbuf}, 0, $len, "";	1880	substr $self->{_tls_wbuf}, 0, $tmp, "";
805	}	1881	}
806	}
807		1882
		1883	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1884	return $self->_tls_error ($tmp)
		1885	if $tmp != $ERROR_WANT_READ
		1886	&& ($tmp != $ERROR_SYSCALL || $!);
		1887	}
		1888
808	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{tls_wbio}))) {	1889	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1890	unless (length $tmp) {
		1891	$self->{_on_starttls}
		1892	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1893	&_freetls;
		1894
		1895	if ($self->{on_stoptls}) {
		1896	$self->{on_stoptls}($self);
		1897	return;
		1898	} else {
		1899	# let's treat SSL-eof as we treat normal EOF
		1900	delete $self->{_rw};
		1901	$self->{_eof} = 1;
		1902	}
		1903	}
		1904
		1905	$self->{_tls_rbuf} .= $tmp;
		1906	$self->_drain_rbuf;
		1907	$self->{tls} or return; # tls session might have gone away in callback
		1908	}
		1909
		1910	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1911	return $self->_tls_error ($tmp)
		1912	if $tmp != $ERROR_WANT_READ
		1913	&& ($tmp != $ERROR_SYSCALL || $!);
		1914
		1915	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
809	$self->{wbuf} .= $buf;	1916	$self->{wbuf} .= $tmp;
810	$self->_drain_wbuf;	1917	$self->_drain_wbuf;
		1918	$self->{tls} or return; # tls session might have gone away in callback
811	}	1919	}
812		1920
813	while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {	1921	$self->{_on_starttls}
814	$self->{rbuf} .= $buf;	1922	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
815	$self->_drain_rbuf;	1923	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
816	}
817
818	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
819
820	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
821	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
822	$self->error;
823	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
824	$! = &Errno::EIO;
825	$self->error;
826	}
827
828	# all others are fine for our purposes
829	}
830	}	1924	}
831		1925
832	=item $handle->starttls ($tls[, $tls_ctx])	1926	=item $handle->starttls ($tls[, $tls_ctx])
833		1927
834	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1928	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
835	object is created, you can also do that at a later time by calling	1929	object is created, you can also do that at a later time by calling
836	C<starttls>.	1930	C<starttls>.
837		1931
		1932	Starting TLS is currently an asynchronous operation - when you push some
		1933	write data and then call C<< ->starttls >> then TLS negotiation will start
		1934	immediately, after which the queued write data is then sent.
		1935
838	The first argument is the same as the C<tls> constructor argument (either	1936	The first argument is the same as the C<tls> constructor argument (either
839	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1937	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
840		1938
841	The second argument is the optional C<Net::SSLeay::CTX> object that is	1939	The second argument is the optional C<AnyEvent::TLS> object that is used
842	used when AnyEvent::Handle has to create its own TLS connection object.	1940	when AnyEvent::Handle has to create its own TLS connection object, or
		1941	a hash reference with C<< key => value >> pairs that will be used to
		1942	construct a new context.
843		1943
844	=cut	1944	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1945	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1946	changed to your liking. Note that the handshake might have already started
		1947	when this function returns.
845		1948
846	# TODO: maybe document...	1949	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1950	handshakes on the same stream. It is best to not attempt to use the
		1951	stream after stopping TLS.
		1952
		1953	This method may invoke callbacks (and therefore the handle might be
		1954	destroyed after it returns).
		1955
		1956	=cut
		1957
		1958	our %TLS_CACHE; #TODO not yet documented, should we?
		1959
847	sub starttls {	1960	sub starttls {
848	my ($self, $ssl, $ctx) = @_;	1961	my ($self, $tls, $ctx) = @_;
849		1962
850	$self->stoptls;	1963	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1964	if $self->{tls};
851		1965
852	if ($ssl eq "accept") {	1966	$self->{tls} = $tls;
853	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1967	$self->{tls_ctx} = $ctx if @_ > 2;
854	Net::SSLeay::set_accept_state ($ssl);	1968
855	} elsif ($ssl eq "connect") {	1969	return unless $self->{fh};
856	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1970
857	Net::SSLeay::set_connect_state ($ssl);	1971	require Net::SSLeay;
		1972
		1973	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1974	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1975
		1976	$tls = delete $self->{tls};
		1977	$ctx = $self->{tls_ctx};
		1978
		1979	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1980
		1981	if ("HASH" eq ref $ctx) {
		1982	require AnyEvent::TLS;
		1983
		1984	if ($ctx->{cache}) {
		1985	my $key = $ctx+0;
		1986	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1987	} else {
		1988	$ctx = new AnyEvent::TLS %$ctx;
		1989	}
		1990	}
858	}	1991
859		1992	$self->{tls_ctx} = $ctx || TLS_CTX ();
860	$self->{tls} = $ssl;	1993	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
861		1994
862	# basically, this is deep magic (because SSL_read should have the same issues)	1995	# basically, this is deep magic (because SSL_read should have the same issues)
863	# but the openssl maintainers basically said: "trust us, it just works".	1996	# but the openssl maintainers basically said: "trust us, it just works".
864	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1997	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
865	# and mismaintained ssleay-module doesn't even offer them).	1998	# and mismaintained ssleay-module doesn't even offer them).
866	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1999	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		2000	#
		2001	# in short: this is a mess.
		2002	#
		2003	# note that we do not try to keep the length constant between writes as we are required to do.
		2004	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		2005	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		2006	# have identity issues in that area.
867	Net::SSLeay::CTX_set_mode ($self->{tls},	2007	# Net::SSLeay::CTX_set_mode ($ssl,
868	(eval { Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	2008	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
869	| (eval { Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	2009	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		2010	Net::SSLeay::CTX_set_mode ($tls, 1|2);
870		2011
871	$self->{tls_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2012	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
872	$self->{tls_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2013	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
873		2014
		2015	Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
		2016	$self->{rbuf} = "";
		2017
874	Net::SSLeay::set_bio ($ssl, $self->{tls_rbio}, $self->{tls_wbio});	2018	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
875		2019
876	$self->{filter_w} = sub {	2020	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
877	$_[0]{tls_wbuf} .= ${$_[1]};	2021	if $self->{on_starttls};
878	&_dotls;	2022
879	};	2023	&_dotls; # need to trigger the initial handshake
880	$self->{filter_r} = sub {	2024	$self->start_read; # make sure we actually do read
881	Net::SSLeay::BIO_write ($_[0]{tls_rbio}, ${$_[1]});
882	&_dotls;
883	};
884	}	2025	}
885		2026
886	=item $handle->stoptls	2027	=item $handle->stoptls
887		2028
888	Destroys the SSL connection, if any. Partial read or write data will be	2029	Shuts down the SSL connection - this makes a proper EOF handshake by
889	lost.	2030	sending a close notify to the other side, but since OpenSSL doesn't
		2031	support non-blocking shut downs, it is not guaranteed that you can re-use
		2032	the stream afterwards.
		2033
		2034	This method may invoke callbacks (and therefore the handle might be
		2035	destroyed after it returns).
890		2036
891	=cut	2037	=cut
892		2038
893	sub stoptls {	2039	sub stoptls {
894	my ($self) = @_;	2040	my ($self) = @_;
895		2041
896	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	2042	if ($self->{tls} && $self->{fh}) {
897	delete $self->{tls_rbio};	2043	Net::SSLeay::shutdown ($self->{tls});
898	delete $self->{tls_wbio};	2044
899	delete $self->{tls_wbuf};	2045	&_dotls;
900	delete $self->{filter_r};	2046
901	delete $self->{filter_w};	2047	# # we don't give a shit. no, we do, but we can't. no...#d#
		2048	# # we, we... have to use openssl :/#d#
		2049	# &_freetls;#d#
		2050	}
902	}	2051	}
		2052
		2053	sub _freetls {
		2054	my ($self) = @_;
		2055
		2056	return unless $self->{tls};
		2057
		2058	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2059	if $self->{tls} > 0;
		2060
		2061	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		2062	}
		2063
		2064	=item $handle->resettls
		2065
		2066	This rarely-used method simply resets and TLS state on the handle, usually
		2067	causing data loss.
		2068
		2069	One case where it may be useful is when you want to skip over the data in
		2070	the stream but you are not interested in interpreting it, so data loss is
		2071	no concern.
		2072
		2073	=cut
		2074
		2075	*resettls = \&_freetls;
903		2076
904	sub DESTROY {	2077	sub DESTROY {
905	my $self = shift;	2078	my ($self) = @_;
906		2079
907	$self->stoptls;	2080	&_freetls;
		2081
		2082	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		2083
		2084	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2085	my $fh = delete $self->{fh};
		2086	my $wbuf = delete $self->{wbuf};
		2087
		2088	my @linger;
		2089
		2090	push @linger, AE::io $fh, 1, sub {
		2091	my $len = syswrite $fh, $wbuf, length $wbuf;
		2092
		2093	if ($len > 0) {
		2094	substr $wbuf, 0, $len, "";
		2095	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
		2096	@linger = (); # end
		2097	}
		2098	};
		2099	push @linger, AE::timer $linger, 0, sub {
		2100	@linger = ();
		2101	};
		2102	}
908	}	2103	}
		2104
		2105	=item $handle->destroy
		2106
		2107	Shuts down the handle object as much as possible - this call ensures that
		2108	no further callbacks will be invoked and as many resources as possible
		2109	will be freed. Any method you will call on the handle object after
		2110	destroying it in this way will be silently ignored (and it will return the
		2111	empty list).
		2112
		2113	Normally, you can just "forget" any references to an AnyEvent::Handle
		2114	object and it will simply shut down. This works in fatal error and EOF
		2115	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2116	callback, so when you want to destroy the AnyEvent::Handle object from
		2117	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2118	that case.
		2119
		2120	Destroying the handle object in this way has the advantage that callbacks
		2121	will be removed as well, so if those are the only reference holders (as
		2122	is common), then one doesn't need to do anything special to break any
		2123	reference cycles.
		2124
		2125	The handle might still linger in the background and write out remaining
		2126	data, as specified by the C<linger> option, however.
		2127
		2128	=cut
		2129
		2130	sub destroy {
		2131	my ($self) = @_;
		2132
		2133	$self->DESTROY;
		2134	%$self = ();
		2135	bless $self, "AnyEvent::Handle::destroyed";
		2136	}
		2137
		2138	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2139	#nop
		2140	}
		2141
		2142	=item $handle->destroyed
		2143
		2144	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2145	->destroy >>, true otherwise.
		2146
		2147	Can be useful to decide whether the handle is still valid after some
		2148	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2149	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2150	can destroy the handle, so work can be avoided by checking sometimes:
		2151
		2152	$hdl->starttls ("accept");
		2153	return if $hdl->destroyed;
		2154	$hdl->push_write (...
		2155
		2156	Note that the call to C<push_write> will silently be ignored if the handle
		2157	has been destroyed, so often you can just ignore the possibility of the
		2158	handle being destroyed.
		2159
		2160	=cut
		2161
		2162	sub destroyed { 0 }
		2163	sub AnyEvent::Handle::destroyed::destroyed { 1 }
909		2164
910	=item AnyEvent::Handle::TLS_CTX	2165	=item AnyEvent::Handle::TLS_CTX
911		2166
912	This function creates and returns the Net::SSLeay::CTX object used by	2167	This function creates and returns the AnyEvent::TLS object used by default
913	default for TLS mode.	2168	for TLS mode.
914		2169
915	The context is created like this:	2170	The context is created by calling L<AnyEvent::TLS> without any arguments.
916
917	Net::SSLeay::load_error_strings;
918	Net::SSLeay::SSLeay_add_ssl_algorithms;
919	Net::SSLeay::randomize;
920
921	my $CTX = Net::SSLeay::CTX_new;
922
923	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
924		2171
925	=cut	2172	=cut
926		2173
927	our $TLS_CTX;	2174	our $TLS_CTX;
928		2175
929	sub TLS_CTX() {	2176	sub TLS_CTX() {
930	$TLS_CTX || do {	2177	$TLS_CTX ||= do {
931	require Net::SSLeay;	2178	require AnyEvent::TLS;
932		2179
933	Net::SSLeay::load_error_strings ();	2180	new AnyEvent::TLS
934	Net::SSLeay::SSLeay_add_ssl_algorithms ();
935	Net::SSLeay::randomize ();
936
937	$TLS_CTX = Net::SSLeay::CTX_new ();
938
939	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
940
941	$TLS_CTX
942	}	2181	}
943	}	2182	}
944		2183
945	=back	2184	=back
946		2185
		2186
		2187	=head1 NONFREQUENTLY ASKED QUESTIONS
		2188
		2189	=over 4
		2190
		2191	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2192	still get further invocations!
		2193
		2194	That's because AnyEvent::Handle keeps a reference to itself when handling
		2195	read or write callbacks.
		2196
		2197	It is only safe to "forget" the reference inside EOF or error callbacks,
		2198	from within all other callbacks, you need to explicitly call the C<<
		2199	->destroy >> method.
		2200
		2201	=item Why is my C<on_eof> callback never called?
		2202
		2203	Probably because your C<on_error> callback is being called instead: When
		2204	you have outstanding requests in your read queue, then an EOF is
		2205	considered an error as you clearly expected some data.
		2206
		2207	To avoid this, make sure you have an empty read queue whenever your handle
		2208	is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
		2209	an C<on_read> handler that simply pushes the first read requests in the
		2210	queue.
		2211
		2212	See also the next question, which explains this in a bit more detail.
		2213
		2214	=item How can I serve requests in a loop?
		2215
		2216	Most protocols consist of some setup phase (authentication for example)
		2217	followed by a request handling phase, where the server waits for requests
		2218	and handles them, in a loop.
		2219
		2220	There are two important variants: The first (traditional, better) variant
		2221	handles requests until the server gets some QUIT command, causing it to
		2222	close the connection first (highly desirable for a busy TCP server). A
		2223	client dropping the connection is an error, which means this variant can
		2224	detect an unexpected detection close.
		2225
		2226	To handle this case, always make sure you have a on-empty read queue, by
		2227	pushing the "read request start" handler on it:
		2228
		2229	# we assume a request starts with a single line
		2230	my @start_request; @start_request = (line => sub {
		2231	my ($hdl, $line) = @_;
		2232
		2233	... handle request
		2234
		2235	# push next request read, possibly from a nested callback
		2236	$hdl->push_read (@start_request);
		2237	});
		2238
		2239	# auth done, now go into request handling loop
		2240	# now push the first @start_request
		2241	$hdl->push_read (@start_request);
		2242
		2243	By always having an outstanding C<push_read>, the handle always expects
		2244	some data and raises the C<EPIPE> error when the connction is dropped
		2245	unexpectedly.
		2246
		2247	The second variant is a protocol where the client can drop the connection
		2248	at any time. For TCP, this means that the server machine may run out of
		2249	sockets easier, and in general, it means you cnanot distinguish a protocl
		2250	failure/client crash from a normal connection close. Nevertheless, these
		2251	kinds of protocols are common (and sometimes even the best solution to the
		2252	problem).
		2253
		2254	Having an outstanding read request at all times is possible if you ignore
		2255	C<EPIPE> errors, but this doesn't help with when the client drops the
		2256	connection during a request, which would still be an error.
		2257
		2258	A better solution is to push the initial request read in an C<on_read>
		2259	callback. This avoids an error, as when the server doesn't expect data
		2260	(i.e. is idly waiting for the next request, an EOF will not raise an
		2261	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2262	and simpler:
		2263
		2264	# auth done, now go into request handling loop
		2265	$hdl->on_read (sub {
		2266	my ($hdl) = @_;
		2267
		2268	# called each time we receive data but the read queue is empty
		2269	# simply start read the request
		2270
		2271	$hdl->push_read (line => sub {
		2272	my ($hdl, $line) = @_;
		2273
		2274	... handle request
		2275
		2276	# do nothing special when the request has been handled, just
		2277	# let the request queue go empty.
		2278	});
		2279	});
		2280
		2281	=item I get different callback invocations in TLS mode/Why can't I pause
		2282	reading?
		2283
		2284	Unlike, say, TCP, TLS connections do not consist of two independent
		2285	communication channels, one for each direction. Or put differently, the
		2286	read and write directions are not independent of each other: you cannot
		2287	write data unless you are also prepared to read, and vice versa.
		2288
		2289	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2290	callback invocations when you are not expecting any read data - the reason
		2291	is that AnyEvent::Handle always reads in TLS mode.
		2292
		2293	During the connection, you have to make sure that you always have a
		2294	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2295	connection (or when you no longer want to use it) you can call the
		2296	C<destroy> method.
		2297
		2298	=item How do I read data until the other side closes the connection?
		2299
		2300	If you just want to read your data into a perl scalar, the easiest way
		2301	to achieve this is by setting an C<on_read> callback that does nothing,
		2302	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2303	will be in C<$_[0]{rbuf}>:
		2304
		2305	$handle->on_read (sub { });
		2306	$handle->on_eof (undef);
		2307	$handle->on_error (sub {
		2308	my $data = delete $_[0]{rbuf};
		2309	});
		2310
		2311	Note that this example removes the C<rbuf> member from the handle object,
		2312	which is not normally allowed by the API. It is expressly permitted in
		2313	this case only, as the handle object needs to be destroyed afterwards.
		2314
		2315	The reason to use C<on_error> is that TCP connections, due to latencies
		2316	and packets loss, might get closed quite violently with an error, when in
		2317	fact all data has been received.
		2318
		2319	It is usually better to use acknowledgements when transferring data,
		2320	to make sure the other side hasn't just died and you got the data
		2321	intact. This is also one reason why so many internet protocols have an
		2322	explicit QUIT command.
		2323
		2324	=item I don't want to destroy the handle too early - how do I wait until
		2325	all data has been written?
		2326
		2327	After writing your last bits of data, set the C<on_drain> callback
		2328	and destroy the handle in there - with the default setting of
		2329	C<low_water_mark> this will be called precisely when all data has been
		2330	written to the socket:
		2331
		2332	$handle->push_write (...);
		2333	$handle->on_drain (sub {
		2334	warn "all data submitted to the kernel\n";
		2335	undef $handle;
		2336	});
		2337
		2338	If you just want to queue some data and then signal EOF to the other side,
		2339	consider using C<< ->push_shutdown >> instead.
		2340
		2341	=item I want to contact a TLS/SSL server, I don't care about security.
		2342
		2343	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2344	connect to it and then create the AnyEvent::Handle with the C<tls>
		2345	parameter:
		2346
		2347	tcp_connect $host, $port, sub {
		2348	my ($fh) = @_;
		2349
		2350	my $handle = new AnyEvent::Handle
		2351	fh => $fh,
		2352	tls => "connect",
		2353	on_error => sub { ... };
		2354
		2355	$handle->push_write (...);
		2356	};
		2357
		2358	=item I want to contact a TLS/SSL server, I do care about security.
		2359
		2360	Then you should additionally enable certificate verification, including
		2361	peername verification, if the protocol you use supports it (see
		2362	L<AnyEvent::TLS>, C<verify_peername>).
		2363
		2364	E.g. for HTTPS:
		2365
		2366	tcp_connect $host, $port, sub {
		2367	my ($fh) = @_;
		2368
		2369	my $handle = new AnyEvent::Handle
		2370	fh => $fh,
		2371	peername => $host,
		2372	tls => "connect",
		2373	tls_ctx => { verify => 1, verify_peername => "https" },
		2374	...
		2375
		2376	Note that you must specify the hostname you connected to (or whatever
		2377	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2378	peername verification will be done.
		2379
		2380	The above will use the system-dependent default set of trusted CA
		2381	certificates. If you want to check against a specific CA, add the
		2382	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2383
		2384	tls_ctx => {
		2385	verify => 1,
		2386	verify_peername => "https",
		2387	ca_file => "my-ca-cert.pem",
		2388	},
		2389
		2390	=item I want to create a TLS/SSL server, how do I do that?
		2391
		2392	Well, you first need to get a server certificate and key. You have
		2393	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2394	self-signed certificate (cheap. check the search engine of your choice,
		2395	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2396	nice program for that purpose).
		2397
		2398	Then create a file with your private key (in PEM format, see
		2399	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2400	file should then look like this:
		2401
		2402	-----BEGIN RSA PRIVATE KEY-----
		2403	...header data
		2404	... lots of base64'y-stuff
		2405	-----END RSA PRIVATE KEY-----
		2406
		2407	-----BEGIN CERTIFICATE-----
		2408	... lots of base64'y-stuff
		2409	-----END CERTIFICATE-----
		2410
		2411	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2412	specify this file as C<cert_file>:
		2413
		2414	tcp_server undef, $port, sub {
		2415	my ($fh) = @_;
		2416
		2417	my $handle = new AnyEvent::Handle
		2418	fh => $fh,
		2419	tls => "accept",
		2420	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2421	...
		2422
		2423	When you have intermediate CA certificates that your clients might not
		2424	know about, just append them to the C<cert_file>.
		2425
		2426	=back
		2427
		2428
		2429	=head1 SUBCLASSING AnyEvent::Handle
		2430
		2431	In many cases, you might want to subclass AnyEvent::Handle.
		2432
		2433	To make this easier, a given version of AnyEvent::Handle uses these
		2434	conventions:
		2435
		2436	=over 4
		2437
		2438	=item * all constructor arguments become object members.
		2439
		2440	At least initially, when you pass a C<tls>-argument to the constructor it
		2441	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2442	mutated later on (for example C<tls> will hold the TLS connection object).
		2443
		2444	=item * other object member names are prefixed with an C<_>.
		2445
		2446	All object members not explicitly documented (internal use) are prefixed
		2447	with an underscore character, so the remaining non-C<_>-namespace is free
		2448	for use for subclasses.
		2449
		2450	=item * all members not documented here and not prefixed with an underscore
		2451	are free to use in subclasses.
		2452
		2453	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2454	member variables, but that's just life. At least it is documented.
		2455
		2456	=back
		2457
947	=head1 AUTHOR	2458	=head1 AUTHOR
948		2459
949	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	2460	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
950		2461
951	=cut	2462	=cut

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