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Revision 1.210 by root, Thu Dec 30 01:53:15 2010 UTC

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict qw(subs vars);
5
6	use AnyEvent ();
7	use AnyEvent::Util qw(WSAEWOULDBLOCK);
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 = 4.232;
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
54	The L<AnyEvent::Intro> tutorial contains some well-documented	38	The L<AnyEvent::Intro> tutorial contains some well-documented
55	AnyEvent::Handle examples.	39	AnyEvent::Handle examples.
56		40
57	In the following, when the documentation refers to of "bytes" then this	41	In the following, where the documentation refers to "bytes", it means
58	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
59	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.
60		47
61	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
62	argument.	49	argument.
63		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
64	=head1 METHODS	82	=head1 METHODS
65		83
66	=over 4	84	=over 4
67		85
68	=item B<new (%args)>	86	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
69		87
70	The constructor supports these arguments (all as key => value pairs).	88	The constructor supports these arguments (all as C<< key => value >> pairs).
71		89
72	=over 4	90	=over 4
73		91
74	=item fh => $filehandle [MANDATORY]	92	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
75		93
76	The filehandle this L<AnyEvent::Handle> object will operate on.	94	The filehandle this L<AnyEvent::Handle> object will operate on.
77
78	NOTE: The filehandle will be set to non-blocking mode (using	95	NOTE: The filehandle will be set to non-blocking mode (using
79	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in	96	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
80	that mode.	97	that mode.
81		98
		99	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
		100
		101	Try to connect to the specified host and service (port), using
		102	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		103	default C<peername>.
		104
		105	You have to specify either this parameter, or C<fh>, above.
		106
		107	It is possible to push requests on the read and write queues, and modify
		108	properties of the stream, even while AnyEvent::Handle is connecting.
		109
		110	When this parameter is specified, then the C<on_prepare>,
		111	C<on_connect_error> and C<on_connect> callbacks will be called under the
		112	appropriate circumstances:
		113
		114	=over 4
		115
82	=item on_eof => $cb->($handle)	116	=item on_prepare => $cb->($handle)
83		117
84	Set the callback to be called when an end-of-file condition is detected,	118	This (rarely used) callback is called before a new connection is
85	i.e. in the case of a socket, when the other side has closed the	119	attempted, but after the file handle has been created (you can access that
86	connection cleanly.	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).
87		123
88	For sockets, this just means that the other side has stopped sending data,	124	The return value of this callback should be the connect timeout value in
89	you can still try to write data, and, in fact, one can return from the eof	125	seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
90	callback and continue writing data, as only the read part has been shut	126	default timeout is to be used).
91	down.
92		127
93	While not mandatory, it is I<highly> recommended to set an eof callback,	128	=item on_connect => $cb->($handle, $host, $port, $retry->())
94	otherwise you might end up with a closed socket while you are still
95	waiting for data.
96		129
97	If an EOF condition has been detected but no C<on_eof> callback has been	130	This callback is called when a connection has been successfully established.
98	set, then a fatal error will be raised with C<$!> set to <0>.
99		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
100	=item on_error => $cb->($handle, $fatal)	154	=item on_error => $cb->($handle, $fatal, $message)
101		155
102	This is the error callback, which is called when, well, some error	156	This is the error callback, which is called when, well, some error
103	occured, such as not being able to resolve the hostname, failure to	157	occured, such as not being able to resolve the hostname, failure to
104	connect or a read error.	158	connect, or a read error.
105		159
106	Some errors are fatal (which is indicated by C<$fatal> being true). On	160	Some errors are fatal (which is indicated by C<$fatal> being true). On
107	fatal errors the handle object will be shut down and will not be usable	161	fatal errors the handle object will be destroyed (by a call to C<< ->
108	(but you are free to look at the current C< ->rbuf >). Examples of fatal	162	destroy >>) after invoking the error callback (which means you are free to
109	errors are an EOF condition with active (but unsatisifable) read watchers	163	examine the handle object). Examples of fatal errors are an EOF condition
110	(C<EPIPE>) or I/O errors.	164	with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
		165	cases where the other side can close the connection at will, it is
		166	often easiest to not report C<EPIPE> errors in this callback.
111		167
		168	AnyEvent::Handle tries to find an appropriate error code for you to check
		169	against, but in some cases (TLS errors), this does not work well. It is
		170	recommended to always output the C<$message> argument in human-readable
		171	error messages (it's usually the same as C<"$!">).
		172
112	Non-fatal errors can be retried by simply returning, but it is recommended	173	Non-fatal errors can be retried by returning, but it is recommended
113	to simply ignore this parameter and instead abondon the handle object	174	to simply ignore this parameter and instead abondon the handle object
114	when this callback is invoked. Examples of non-fatal errors are timeouts	175	when this callback is invoked. Examples of non-fatal errors are timeouts
115	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).	176	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
116		177
117	On callback entrance, the value of C<$!> contains the operating system	178	On entry to the callback, the value of C<$!> contains the operating
118	error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).	179	system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		180	C<EPROTO>).
119		181
120	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
121	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
122	C<croak>.	184	C<croak>.
123		185
124	=item on_read => $cb->($handle)	186	=item on_read => $cb->($handle)
125		187
126	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
127	and no read request is in the queue (unlike read queue callbacks, this	189	and no read request is in the queue (unlike read queue callbacks, this
128	callback will only be called when at least one octet of data is in the	190	callback will only be called when at least one octet of data is in the
129	read buffer).	191	read buffer).
130		192
131	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 >>
132	method or access the C<$handle->{rbuf}> member directly.	194	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		195	must not enlarge or modify the read buffer, you can only remove data at
		196	the beginning from it.
133		197
		198	You can also call C<< ->push_read (...) >> or any other function that
		199	modifies the read queue. Or do both. Or ...
		200
134	When an EOF condition is detected then AnyEvent::Handle will first try to	201	When an EOF condition is detected, AnyEvent::Handle will first try to
135	feed all the remaining data to the queued callbacks and C<on_read> before	202	feed all the remaining data to the queued callbacks and C<on_read> before
136	calling the C<on_eof> callback. If no progress can be made, then a fatal	203	calling the C<on_eof> callback. If no progress can be made, then a fatal
137	error will be raised (with C<$!> set to C<EPIPE>).	204	error will be raised (with C<$!> set to C<EPIPE>).
138		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
139	=item on_drain => $cb->($handle)	227	=item on_drain => $cb->($handle)
140		228
141	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
142	(or when the callback is set and the buffer is empty already).	230	(or immediately if the buffer is empty already).
143		231
144	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.
145		233
146	This callback is useful when you don't want to put all of your write data	234	This callback is useful when you don't want to put all of your write data
147	into the queue at once, for example, when you want to write the contents	235	into the queue at once, for example, when you want to write the contents
…		…
149	memory and push it into the queue, but instead only read more data from	237	memory and push it into the queue, but instead only read more data from
150	the file when the write queue becomes empty.	238	the file when the write queue becomes empty.
151		239
152	=item timeout => $fractional_seconds	240	=item timeout => $fractional_seconds
153		241
		242	=item rtimeout => $fractional_seconds
		243
		244	=item wtimeout => $fractional_seconds
		245
154	If non-zero, then this enables an "inactivity" timeout: whenever this many	246	If non-zero, then these enables an "inactivity" timeout: whenever this
155	seconds pass without a successful read or write on the underlying file	247	many seconds pass without a successful read or write on the underlying
156	handle, the C<on_timeout> callback will be invoked (and if that one is	248	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
157	missing, an C<ETIMEDOUT> error will be raised).	249	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		250	error will be raised).
158		251
		252	There are three variants of the timeouts that work independently
		253	of each other, for both read and write, just read, and just write:
		254	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		255	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		256	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		257
159	Note that timeout processing is also active when you currently do not have	258	Note that timeout processing is active even when you do not have
160	any outstanding read or write requests: If you plan to keep the connection	259	any outstanding read or write requests: If you plan to keep the connection
161	idle then you should disable the timout temporarily or ignore the timeout	260	idle then you should disable the timeout temporarily or ignore the timeout
162	in the C<on_timeout> callback.	261	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		262	restart the timeout.
163		263
164	Zero (the default) disables this timeout.	264	Zero (the default) disables this timeout.
165		265
166	=item on_timeout => $cb->($handle)	266	=item on_timeout => $cb->($handle)
167		267
…		…
171		271
172	=item rbuf_max => <bytes>	272	=item rbuf_max => <bytes>
173		273
174	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	274	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
175	when the read buffer ever (strictly) exceeds this size. This is useful to	275	when the read buffer ever (strictly) exceeds this size. This is useful to
176	avoid denial-of-service attacks.	276	avoid some forms of denial-of-service attacks.
177		277
178	For example, a server accepting connections from untrusted sources should	278	For example, a server accepting connections from untrusted sources should
179	be configured to accept only so-and-so much data that it cannot act on	279	be configured to accept only so-and-so much data that it cannot act on
180	(for example, when expecting a line, an attacker could send an unlimited	280	(for example, when expecting a line, an attacker could send an unlimited
181	amount of data without a callback ever being called as long as the line	281	amount of data without a callback ever being called as long as the line
182	isn't finished).	282	isn't finished).
183		283
		284	=item wbuf_max => <bytes>
		285
		286	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		287	when the write buffer ever (strictly) exceeds this size. This is useful to
		288	avoid some forms of denial-of-service attacks.
		289
		290	Although the units of this parameter is bytes, this is the I<raw> number
		291	of bytes not yet accepted by the kernel. This can make a difference when
		292	you e.g. use TLS, as TLS typically makes your write data larger (but it
		293	can also make it smaller due to compression).
		294
		295	As an example of when this limit is useful, take a chat server that sends
		296	chat messages to a client. If the client does not read those in a timely
		297	manner then the send buffer in the server would grow unbounded.
		298
184	=item autocork => <boolean>	299	=item autocork => <boolean>
185		300
186	When disabled (the default), then C<push_write> will try to immediately	301	When disabled (the default), C<push_write> will try to immediately
187	write the data to the handle if possible. This avoids having to register	302	write the data to the handle if possible. This avoids having to register
188	a write watcher and wait for the next event loop iteration, but can be	303	a write watcher and wait for the next event loop iteration, but can
189	inefficient if you write multiple small chunks (this disadvantage is	304	be inefficient if you write multiple small chunks (on the wire, this
190	usually avoided by your kernel's nagle algorithm, see C<low_delay>).	305	disadvantage is usually avoided by your kernel's nagle algorithm, see
		306	C<no_delay>, but this option can save costly syscalls).
191		307
192	When enabled, then writes will always be queued till the next event loop	308	When enabled, writes will always be queued till the next event loop
193	iteration. This is efficient when you do many small writes per iteration,	309	iteration. This is efficient when you do many small writes per iteration,
194	but less efficient when you do a single write only.	310	but less efficient when you do a single write only per iteration (or when
		311	the write buffer often is full). It also increases write latency.
195		312
196	=item no_delay => <boolean>	313	=item no_delay => <boolean>
197		314
198	When doing small writes on sockets, your operating system kernel might	315	When doing small writes on sockets, your operating system kernel might
199	wait a bit for more data before actually sending it out. This is called	316	wait a bit for more data before actually sending it out. This is called
200	the Nagle algorithm, and usually it is beneficial.	317	the Nagle algorithm, and usually it is beneficial.
201		318
202	In some situations you want as low a delay as possible, which cna be	319	In some situations you want as low a delay as possible, which can be
203	accomplishd by setting this option to true.	320	accomplishd by setting this option to a true value.
204		321
205	The default is your opertaing system's default behaviour, this option	322	The default is your operating system's default behaviour (most likely
206	explicitly enables or disables it, if possible.	323	enabled). This option explicitly enables or disables it, if possible.
		324
		325	=item keepalive => <boolean>
		326
		327	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		328	normally, TCP connections have no time-out once established, so TCP
		329	connections, once established, can stay alive forever even when the other
		330	side has long gone. TCP keepalives are a cheap way to take down long-lived
		331	TCP connections when the other side becomes unreachable. While the default
		332	is OS-dependent, TCP keepalives usually kick in after around two hours,
		333	and, if the other side doesn't reply, take down the TCP connection some 10
		334	to 15 minutes later.
		335
		336	It is harmless to specify this option for file handles that do not support
		337	keepalives, and enabling it on connections that are potentially long-lived
		338	is usually a good idea.
		339
		340	=item oobinline => <boolean>
		341
		342	BSD majorly fucked up the implementation of TCP urgent data. The result
		343	is that almost no OS implements TCP according to the specs, and every OS
		344	implements it slightly differently.
		345
		346	If you want to handle TCP urgent data, then setting this flag (the default
		347	is enabled) gives you the most portable way of getting urgent data, by
		348	putting it into the stream.
		349
		350	Since BSD emulation of OOB data on top of TCP's urgent data can have
		351	security implications, AnyEvent::Handle sets this flag automatically
		352	unless explicitly specified. Note that setting this flag after
		353	establishing a connection I<may> be a bit too late (data loss could
		354	already have occured on BSD systems), but at least it will protect you
		355	from most attacks.
207		356
208	=item read_size => <bytes>	357	=item read_size => <bytes>
209		358
210	The default read block size (the amount of bytes this module will try to read	359	The initial read block size, the number of bytes this module will try to
211	during each (loop iteration). Default: C<8192>.	360	read during each loop iteration. Each handle object will consume at least
		361	this amount of memory for the read buffer as well, so when handling many
		362	connections requirements). See also C<max_read_size>. Default: C<2048>.
		363
		364	=item max_read_size => <bytes>
		365
		366	The maximum read buffer size used by the dynamic adjustment
		367	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		368	one go it will double C<read_size> up to the maximum given by this
		369	option. Default: C<131072> or C<read_size>, whichever is higher.
212		370
213	=item low_water_mark => <bytes>	371	=item low_water_mark => <bytes>
214		372
215	Sets the amount of bytes (default: C<0>) that make up an "empty" write	373	Sets the number of bytes (default: C<0>) that make up an "empty" write
216	buffer: If the write reaches this size or gets even samller it is	374	buffer: If the buffer reaches this size or gets even samller it is
217	considered empty.	375	considered empty.
218		376
		377	Sometimes it can be beneficial (for performance reasons) to add data to
		378	the write buffer before it is fully drained, but this is a rare case, as
		379	the operating system kernel usually buffers data as well, so the default
		380	is good in almost all cases.
		381
219	=item linger => <seconds>	382	=item linger => <seconds>
220		383
221	If non-zero (default: C<3600>), then the destructor of the	384	If this is non-zero (default: C<3600>), the destructor of the
222	AnyEvent::Handle object will check wether there is still outstanding write	385	AnyEvent::Handle object will check whether there is still outstanding
223	data and will install a watcher that will write out this data. No errors	386	write data and will install a watcher that will write this data to the
224	will be reported (this mostly matches how the operating system treats	387	socket. No errors will be reported (this mostly matches how the operating
225	outstanding data at socket close time).	388	system treats outstanding data at socket close time).
226		389
227	This will not work for partial TLS data that could not yet been	390	This will not work for partial TLS data that could not be encoded
228	encoded. This data will be lost.	391	yet. This data will be lost. Calling the C<stoptls> method in time might
		392	help.
		393
		394	=item peername => $string
		395
		396	A string used to identify the remote site - usually the DNS hostname
		397	(I<not> IDN!) used to create the connection, rarely the IP address.
		398
		399	Apart from being useful in error messages, this string is also used in TLS
		400	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		401	verification will be skipped when C<peername> is not specified or is
		402	C<undef>.
229		403
230	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	404	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
231		405
232	When this parameter is given, it enables TLS (SSL) mode, that means	406	When this parameter is given, it enables TLS (SSL) mode, that means
233	AnyEvent will start a TLS handshake and will transparently encrypt/decrypt	407	AnyEvent will start a TLS handshake as soon as the connection has been
234	data.	408	established and will transparently encrypt/decrypt data afterwards.
		409
		410	All TLS protocol errors will be signalled as C<EPROTO>, with an
		411	appropriate error message.
235		412
236	TLS mode requires Net::SSLeay to be installed (it will be loaded	413	TLS mode requires Net::SSLeay to be installed (it will be loaded
237	automatically when you try to create a TLS handle).	414	automatically when you try to create a TLS handle): this module doesn't
		415	have a dependency on that module, so if your module requires it, you have
		416	to add the dependency yourself.
238		417
239	Unlike TCP, TLS has a server and client side: for the TLS server side, use	418	Unlike TCP, TLS has a server and client side: for the TLS server side, use
240	C<accept>, and for the TLS client side of a connection, use C<connect>	419	C<accept>, and for the TLS client side of a connection, use C<connect>
241	mode.	420	mode.
242		421
243	You can also provide your own TLS connection object, but you have	422	You can also provide your own TLS connection object, but you have
244	to make sure that you call either C<Net::SSLeay::set_connect_state>	423	to make sure that you call either C<Net::SSLeay::set_connect_state>
245	or C<Net::SSLeay::set_accept_state> on it before you pass it to	424	or C<Net::SSLeay::set_accept_state> on it before you pass it to
246	AnyEvent::Handle.	425	AnyEvent::Handle. Also, this module will take ownership of this connection
		426	object.
247		427
		428	At some future point, AnyEvent::Handle might switch to another TLS
		429	implementation, then the option to use your own session object will go
		430	away.
		431
		432	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		433	passing in the wrong integer will lead to certain crash. This most often
		434	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		435	segmentation fault.
		436
248	See the C<starttls> method for when need to start TLS negotiation later.	437	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
249		438
250	=item tls_ctx => $ssl_ctx	439	=item tls_ctx => $anyevent_tls
251		440
252	Use the given Net::SSLeay::CTX object to create the new TLS connection	441	Use the given C<AnyEvent::TLS> object to create the new TLS connection
253	(unless a connection object was specified directly). If this parameter is	442	(unless a connection object was specified directly). If this
254	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	443	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		444	C<AnyEvent::Handle::TLS_CTX>.
		445
		446	Instead of an object, you can also specify a hash reference with C<< key
		447	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		448	new TLS context object.
		449
		450	=item on_starttls => $cb->($handle, $success[, $error_message])
		451
		452	This callback will be invoked when the TLS/SSL handshake has finished. If
		453	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		454	(C<on_stoptls> will not be called in this case).
		455
		456	The session in C<< $handle->{tls} >> can still be examined in this
		457	callback, even when the handshake was not successful.
		458
		459	TLS handshake failures will not cause C<on_error> to be invoked when this
		460	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		461
		462	Without this callback, handshake failures lead to C<on_error> being
		463	called as usual.
		464
		465	Note that you cannot just call C<starttls> again in this callback. If you
		466	need to do that, start an zero-second timer instead whose callback can
		467	then call C<< ->starttls >> again.
		468
		469	=item on_stoptls => $cb->($handle)
		470
		471	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		472	set, then it will be invoked after freeing the TLS session. If it is not,
		473	then a TLS shutdown condition will be treated like a normal EOF condition
		474	on the handle.
		475
		476	The session in C<< $handle->{tls} >> can still be examined in this
		477	callback.
		478
		479	This callback will only be called on TLS shutdowns, not when the
		480	underlying handle signals EOF.
255		481
256	=item json => JSON or JSON::XS object	482	=item json => JSON or JSON::XS object
257		483
258	This is the json coder object used by the C<json> read and write types.	484	This is the json coder object used by the C<json> read and write types.
259		485
260	If you don't supply it, then AnyEvent::Handle will create and use a	486	If you don't supply it, then AnyEvent::Handle will create and use a
261	suitable one, which will write and expect UTF-8 encoded JSON texts.	487	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		488	texts.
262		489
263	Note that you are responsible to depend on the JSON module if you want to	490	Note that you are responsible to depend on the JSON module if you want to
264	use this functionality, as AnyEvent does not have a dependency itself.	491	use this functionality, as AnyEvent does not have a dependency itself.
265		492
266	=item filter_r => $cb
267
268	=item filter_w => $cb
269
270	These exist, but are undocumented at this time.
271
272	=back	493	=back
273		494
274	=cut	495	=cut
275		496
276	sub new {	497	sub new {
277	my $class = shift;	498	my $class = shift;
278
279	my $self = bless { @_ }, $class;	499	my $self = bless { @_ }, $class;
280		500
281	$self->{fh} or Carp::croak "mandatory argument fh is missing";	501	if ($self->{fh}) {
		502	$self->_start;
		503	return unless $self->{fh}; # could be gone by now
		504
		505	} elsif ($self->{connect}) {
		506	require AnyEvent::Socket;
		507
		508	$self->{peername} = $self->{connect}[0]
		509	unless exists $self->{peername};
		510
		511	$self->{_skip_drain_rbuf} = 1;
		512
		513	{
		514	Scalar::Util::weaken (my $self = $self);
		515
		516	$self->{_connect} =
		517	AnyEvent::Socket::tcp_connect (
		518	$self->{connect}[0],
		519	$self->{connect}[1],
		520	sub {
		521	my ($fh, $host, $port, $retry) = @_;
		522
		523	delete $self->{_connect}; # no longer needed
		524
		525	if ($fh) {
		526	$self->{fh} = $fh;
		527
		528	delete $self->{_skip_drain_rbuf};
		529	$self->_start;
		530
		531	$self->{on_connect}
		532	and $self->{on_connect}($self, $host, $port, sub {
		533	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		534	$self->{_skip_drain_rbuf} = 1;
		535	&$retry;
		536	});
		537
		538	} else {
		539	if ($self->{on_connect_error}) {
		540	$self->{on_connect_error}($self, "$!");
		541	$self->destroy;
		542	} else {
		543	$self->_error ($!, 1);
		544	}
		545	}
		546	},
		547	sub {
		548	local $self->{fh} = $_[0];
		549
		550	$self->{on_prepare}
		551	? $self->{on_prepare}->($self)
		552	: ()
		553	}
		554	);
		555	}
		556
		557	} else {
		558	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		559	}
		560
		561	$self
		562	}
		563
		564	sub _start {
		565	my ($self) = @_;
		566
		567	# too many clueless people try to use udp and similar sockets
		568	# with AnyEvent::Handle, do them a favour.
		569	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		570	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		571	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
282		572
283	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	573	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
284		574
285	if ($self->{tls}) {	575	$self->{_activity} =
286	require Net::SSLeay;	576	$self->{_ractivity} =
		577	$self->{_wactivity} = AE::now;
		578
		579	$self->{read_size} ||= 2048;
		580	$self->{max_read_size} = $self->{read_size}
		581	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		582
		583	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		584	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		585	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		586
		587	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		588	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		589
		590	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		591
287	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	592	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
288	}	593	if $self->{tls};
289		594
290	$self->{_activity} = AnyEvent->now;
291	$self->_timeout;
292
293	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};	595	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
294	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
295		596
296	$self->start_read	597	$self->start_read
297	if $self->{on_read};	598	if $self->{on_read} || @{ $self->{_queue} };
298		599
299	$self	600	$self->_drain_wbuf;
300	}
301
302	sub _shutdown {
303	my ($self) = @_;
304
305	delete $self->{_tw};
306	delete $self->{_rw};
307	delete $self->{_ww};
308	delete $self->{fh};
309
310	$self->stoptls;
311
312	delete $self->{on_read};
313	delete $self->{_queue};
314	}	601	}
315		602
316	sub _error {	603	sub _error {
317	my ($self, $errno, $fatal) = @_;	604	my ($self, $errno, $fatal, $message) = @_;
318
319	$self->_shutdown
320	if $fatal;
321		605
322	$! = $errno;	606	$! = $errno;
		607	$message ||= "$!";
323		608
324	if ($self->{on_error}) {	609	if ($self->{on_error}) {
325	$self->{on_error}($self, $fatal);	610	$self->{on_error}($self, $fatal, $message);
326	} else {	611	$self->destroy if $fatal;
		612	} elsif ($self->{fh} || $self->{connect}) {
		613	$self->destroy;
327	Carp::croak "AnyEvent::Handle uncaught error: $!";	614	Carp::croak "AnyEvent::Handle uncaught error: $message";
328	}	615	}
329	}	616	}
330		617
331	=item $fh = $handle->fh	618	=item $fh = $handle->fh
332		619
333	This method returns the file handle of the L<AnyEvent::Handle> object.	620	This method returns the file handle used to create the L<AnyEvent::Handle> object.
334		621
335	=cut	622	=cut
336		623
337	sub fh { $_[0]{fh} }	624	sub fh { $_[0]{fh} }
338		625
…		…
356	$_[0]{on_eof} = $_[1];	643	$_[0]{on_eof} = $_[1];
357	}	644	}
358		645
359	=item $handle->on_timeout ($cb)	646	=item $handle->on_timeout ($cb)
360		647
361	Replace the current C<on_timeout> callback, or disables the callback	648	=item $handle->on_rtimeout ($cb)
362	(but not the timeout) if C<$cb> = C<undef>. See C<timeout> constructor
363	argument.
364		649
365	=cut	650	=item $handle->on_wtimeout ($cb)
366		651
367	sub on_timeout {	652	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
368	$_[0]{on_timeout} = $_[1];	653	callback, or disables the callback (but not the timeout) if C<$cb> =
369	}	654	C<undef>. See the C<timeout> constructor argument and method.
		655
		656	=cut
		657
		658	# see below
370		659
371	=item $handle->autocork ($boolean)	660	=item $handle->autocork ($boolean)
372		661
373	Enables or disables the current autocork behaviour (see C<autocork>	662	Enables or disables the current autocork behaviour (see C<autocork>
374	constructor argument).	663	constructor argument). Changes will only take effect on the next write.
375		664
376	=cut	665	=cut
		666
		667	sub autocork {
		668	$_[0]{autocork} = $_[1];
		669	}
377		670
378	=item $handle->no_delay ($boolean)	671	=item $handle->no_delay ($boolean)
379		672
380	Enables or disables the C<no_delay> setting (see constructor argument of	673	Enables or disables the C<no_delay> setting (see constructor argument of
381	the same name for details).	674	the same name for details).
…		…
383	=cut	676	=cut
384		677
385	sub no_delay {	678	sub no_delay {
386	$_[0]{no_delay} = $_[1];	679	$_[0]{no_delay} = $_[1];
387		680
		681	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		682	if $_[0]{fh};
		683	}
		684
		685	=item $handle->keepalive ($boolean)
		686
		687	Enables or disables the C<keepalive> setting (see constructor argument of
		688	the same name for details).
		689
		690	=cut
		691
		692	sub keepalive {
		693	$_[0]{keepalive} = $_[1];
		694
388	eval {	695	eval {
389	local $SIG{__DIE__};	696	local $SIG{__DIE__};
390	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];	697	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		698	if $_[0]{fh};
391	};	699	};
392	}	700	}
393		701
		702	=item $handle->oobinline ($boolean)
		703
		704	Enables or disables the C<oobinline> setting (see constructor argument of
		705	the same name for details).
		706
		707	=cut
		708
		709	sub oobinline {
		710	$_[0]{oobinline} = $_[1];
		711
		712	eval {
		713	local $SIG{__DIE__};
		714	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		715	if $_[0]{fh};
		716	};
		717	}
		718
		719	=item $handle->keepalive ($boolean)
		720
		721	Enables or disables the C<keepalive> setting (see constructor argument of
		722	the same name for details).
		723
		724	=cut
		725
		726	sub keepalive {
		727	$_[0]{keepalive} = $_[1];
		728
		729	eval {
		730	local $SIG{__DIE__};
		731	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		732	if $_[0]{fh};
		733	};
		734	}
		735
		736	=item $handle->on_starttls ($cb)
		737
		738	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		739
		740	=cut
		741
		742	sub on_starttls {
		743	$_[0]{on_starttls} = $_[1];
		744	}
		745
		746	=item $handle->on_stoptls ($cb)
		747
		748	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		749
		750	=cut
		751
		752	sub on_stoptls {
		753	$_[0]{on_stoptls} = $_[1];
		754	}
		755
		756	=item $handle->rbuf_max ($max_octets)
		757
		758	Configures the C<rbuf_max> setting (C<undef> disables it).
		759
		760	=item $handle->wbuf_max ($max_octets)
		761
		762	Configures the C<wbuf_max> setting (C<undef> disables it).
		763
		764	=cut
		765
		766	sub rbuf_max {
		767	$_[0]{rbuf_max} = $_[1];
		768	}
		769
		770	sub rbuf_max {
		771	$_[0]{wbuf_max} = $_[1];
		772	}
		773
394	#############################################################################	774	#############################################################################
395		775
396	=item $handle->timeout ($seconds)	776	=item $handle->timeout ($seconds)
397		777
		778	=item $handle->rtimeout ($seconds)
		779
		780	=item $handle->wtimeout ($seconds)
		781
398	Configures (or disables) the inactivity timeout.	782	Configures (or disables) the inactivity timeout.
399		783
400	=cut	784	=item $handle->timeout_reset
401		785
402	sub timeout {	786	=item $handle->rtimeout_reset
		787
		788	=item $handle->wtimeout_reset
		789
		790	Reset the activity timeout, as if data was received or sent.
		791
		792	These methods are cheap to call.
		793
		794	=cut
		795
		796	for my $dir ("", "r", "w") {
		797	my $timeout = "${dir}timeout";
		798	my $tw = "_${dir}tw";
		799	my $on_timeout = "on_${dir}timeout";
		800	my $activity = "_${dir}activity";
		801	my $cb;
		802
		803	*$on_timeout = sub {
		804	$_[0]{$on_timeout} = $_[1];
		805	};
		806
		807	*$timeout = sub {
403	my ($self, $timeout) = @_;	808	my ($self, $new_value) = @_;
404		809
		810	$new_value >= 0
		811	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		812
405	$self->{timeout} = $timeout;	813	$self->{$timeout} = $new_value;
406	$self->_timeout;	814	delete $self->{$tw}; &$cb;
407	}	815	};
408		816
		817	*{"${dir}timeout_reset"} = sub {
		818	$_[0]{$activity} = AE::now;
		819	};
		820
		821	# main workhorse:
409	# reset the timeout watcher, as neccessary	822	# reset the timeout watcher, as neccessary
410	# also check for time-outs	823	# also check for time-outs
411	sub _timeout {	824	$cb = sub {
412	my ($self) = @_;	825	my ($self) = @_;
413		826
414	if ($self->{timeout}) {	827	if ($self->{$timeout} && $self->{fh}) {
415	my $NOW = AnyEvent->now;	828	my $NOW = AE::now;
416		829
417	# when would the timeout trigger?	830	# when would the timeout trigger?
418	my $after = $self->{_activity} + $self->{timeout} - $NOW;	831	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
419		832
420	# now or in the past already?	833	# now or in the past already?
421	if ($after <= 0) {	834	if ($after <= 0) {
422	$self->{_activity} = $NOW;	835	$self->{$activity} = $NOW;
423		836
424	if ($self->{on_timeout}) {	837	if ($self->{$on_timeout}) {
425	$self->{on_timeout}($self);	838	$self->{$on_timeout}($self);
426	} else {	839	} else {
427	$self->_error (&Errno::ETIMEDOUT);	840	$self->_error (Errno::ETIMEDOUT);
		841	}
		842
		843	# callback could have changed timeout value, optimise
		844	return unless $self->{$timeout};
		845
		846	# calculate new after
		847	$after = $self->{$timeout};
428	}	848	}
429		849
430	# callback could have changed timeout value, optimise	850	Scalar::Util::weaken $self;
431	return unless $self->{timeout};	851	return unless $self; # ->error could have destroyed $self
432		852
433	# calculate new after	853	$self->{$tw} ||= AE::timer $after, 0, sub {
434	$after = $self->{timeout};	854	delete $self->{$tw};
		855	$cb->($self);
		856	};
		857	} else {
		858	delete $self->{$tw};
435	}	859	}
436
437	Scalar::Util::weaken $self;
438	return unless $self; # ->error could have destroyed $self
439
440	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
441	delete $self->{_tw};
442	$self->_timeout;
443	});
444	} else {
445	delete $self->{_tw};
446	}	860	}
447	}	861	}
448		862
449	#############################################################################	863	#############################################################################
450		864
…		…
466	=item $handle->on_drain ($cb)	880	=item $handle->on_drain ($cb)
467		881
468	Sets the C<on_drain> callback or clears it (see the description of	882	Sets the C<on_drain> callback or clears it (see the description of
469	C<on_drain> in the constructor).	883	C<on_drain> in the constructor).
470		884
		885	This method may invoke callbacks (and therefore the handle might be
		886	destroyed after it returns).
		887
471	=cut	888	=cut
472		889
473	sub on_drain {	890	sub on_drain {
474	my ($self, $cb) = @_;	891	my ($self, $cb) = @_;
475		892
476	$self->{on_drain} = $cb;	893	$self->{on_drain} = $cb;
477		894
478	$cb->($self)	895	$cb->($self)
479	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	896	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
480	}	897	}
481		898
482	=item $handle->push_write ($data)	899	=item $handle->push_write ($data)
483		900
484	Queues the given scalar to be written. You can push as much data as you	901	Queues the given scalar to be written. You can push as much data as
485	want (only limited by the available memory), as C<AnyEvent::Handle>	902	you want (only limited by the available memory and C<wbuf_max>), as
486	buffers it independently of the kernel.	903	C<AnyEvent::Handle> buffers it independently of the kernel.
		904
		905	This method may invoke callbacks (and therefore the handle might be
		906	destroyed after it returns).
487		907
488	=cut	908	=cut
489		909
490	sub _drain_wbuf {	910	sub _drain_wbuf {
491	my ($self) = @_;	911	my ($self) = @_;
…		…
495	Scalar::Util::weaken $self;	915	Scalar::Util::weaken $self;
496		916
497	my $cb = sub {	917	my $cb = sub {
498	my $len = syswrite $self->{fh}, $self->{wbuf};	918	my $len = syswrite $self->{fh}, $self->{wbuf};
499		919
500	if ($len >= 0) {	920	if (defined $len) {
501	substr $self->{wbuf}, 0, $len, "";	921	substr $self->{wbuf}, 0, $len, "";
502		922
503	$self->{_activity} = AnyEvent->now;	923	$self->{_activity} = $self->{_wactivity} = AE::now;
504		924
505	$self->{on_drain}($self)	925	$self->{on_drain}($self)
506	if $self->{low_water_mark} >= length $self->{wbuf}	926	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
507	&& $self->{on_drain};	927	&& $self->{on_drain};
508		928
509	delete $self->{_ww} unless length $self->{wbuf};	929	delete $self->{_ww} unless length $self->{wbuf};
510	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {	930	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
511	$self->_error ($!, 1);	931	$self->_error ($!, 1);
…		…
514		934
515	# try to write data immediately	935	# try to write data immediately
516	$cb->() unless $self->{autocork};	936	$cb->() unless $self->{autocork};
517		937
518	# if still data left in wbuf, we need to poll	938	# if still data left in wbuf, we need to poll
519	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)	939	$self->{_ww} = AE::io $self->{fh}, 1, $cb
520	if length $self->{wbuf};	940	if length $self->{wbuf};
		941
		942	if (
		943	defined $self->{wbuf_max}
		944	&& $self->{wbuf_max} < length $self->{wbuf}
		945	) {
		946	$self->_error (Errno::ENOSPC, 1), return;
		947	}
521	};	948	};
522	}	949	}
523		950
524	our %WH;	951	our %WH;
525		952
		953	# deprecated
526	sub register_write_type($$) {	954	sub register_write_type($$) {
527	$WH{$_[0]} = $_[1];	955	$WH{$_[0]} = $_[1];
528	}	956	}
529		957
530	sub push_write {	958	sub push_write {
531	my $self = shift;	959	my $self = shift;
532		960
533	if (@_ > 1) {	961	if (@_ > 1) {
534	my $type = shift;	962	my $type = shift;
535		963
		964	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
536	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	965	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
537	->($self, @_);	966	->($self, @_);
538	}	967	}
539		968
		969	# we downgrade here to avoid hard-to-track-down bugs,
		970	# and diagnose the problem earlier and better.
		971
540	if ($self->{filter_w}) {	972	if ($self->{tls}) {
541	$self->{filter_w}($self, \$_[0]);	973	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		974	&_dotls ($self) if $self->{fh};
542	} else {	975	} else {
543	$self->{wbuf} .= $_[0];	976	utf8::downgrade $self->{wbuf} .= $_[0];
544	$self->_drain_wbuf;	977	$self->_drain_wbuf if $self->{fh};
545	}	978	}
546	}	979	}
547		980
548	=item $handle->push_write (type => @args)	981	=item $handle->push_write (type => @args)
549		982
550	Instead of formatting your data yourself, you can also let this module do	983	Instead of formatting your data yourself, you can also let this module
551	the job by specifying a type and type-specific arguments.	984	do the job by specifying a type and type-specific arguments. You
		985	can also specify the (fully qualified) name of a package, in which
		986	case AnyEvent tries to load the package and then expects to find the
		987	C<anyevent_write_type> function inside (see "custom write types", below).
552		988
553	Predefined types are (if you have ideas for additional types, feel free to	989	Predefined types are (if you have ideas for additional types, feel free to
554	drop by and tell us):	990	drop by and tell us):
555		991
556	=over 4	992	=over 4
…		…
563	=cut	999	=cut
564		1000
565	register_write_type netstring => sub {	1001	register_write_type netstring => sub {
566	my ($self, $string) = @_;	1002	my ($self, $string) = @_;
567		1003
568	sprintf "%d:%s,", (length $string), $string	1004	(length $string) . ":$string,"
569	};	1005	};
570		1006
571	=item packstring => $format, $data	1007	=item packstring => $format, $data
572		1008
573	An octet string prefixed with an encoded length. The encoding C<$format>	1009	An octet string prefixed with an encoded length. The encoding C<$format>
…		…
613	Other languages could read single lines terminated by a newline and pass	1049	Other languages could read single lines terminated by a newline and pass
614	this line into their JSON decoder of choice.	1050	this line into their JSON decoder of choice.
615		1051
616	=cut	1052	=cut
617		1053
		1054	sub json_coder() {
		1055	eval { require JSON::XS; JSON::XS->new->utf8 }
		1056	|| do { require JSON; JSON->new->utf8 }
		1057	}
		1058
618	register_write_type json => sub {	1059	register_write_type json => sub {
619	my ($self, $ref) = @_;	1060	my ($self, $ref) = @_;
620		1061
621	require JSON;	1062	my $json = $self->{json} ||= json_coder;
622		1063
623	$self->{json} ? $self->{json}->encode ($ref)	1064	$json->encode ($ref)
624	: JSON::encode_json ($ref)
625	};	1065	};
626		1066
627	=item storable => $reference	1067	=item storable => $reference
628		1068
629	Freezes the given reference using L<Storable> and writes it to the	1069	Freezes the given reference using L<Storable> and writes it to the
…		…
639	pack "w/a*", Storable::nfreeze ($ref)	1079	pack "w/a*", Storable::nfreeze ($ref)
640	};	1080	};
641		1081
642	=back	1082	=back
643		1083
644	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)	1084	=item $handle->push_shutdown
645		1085
646	This function (not method) lets you add your own types to C<push_write>.	1086	Sometimes you know you want to close the socket after writing your data
		1087	before it was actually written. One way to do that is to replace your
		1088	C<on_drain> handler by a callback that shuts down the socket (and set
		1089	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1090	replaces the C<on_drain> callback with:
		1091
		1092	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		1093
		1094	This simply shuts down the write side and signals an EOF condition to the
		1095	the peer.
		1096
		1097	You can rely on the normal read queue and C<on_eof> handling
		1098	afterwards. This is the cleanest way to close a connection.
		1099
		1100	This method may invoke callbacks (and therefore the handle might be
		1101	destroyed after it returns).
		1102
		1103	=cut
		1104
		1105	sub push_shutdown {
		1106	my ($self) = @_;
		1107
		1108	delete $self->{low_water_mark};
		1109	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1110	}
		1111
		1112	=item custom write types - Package::anyevent_write_type $handle, @args
		1113
		1114	Instead of one of the predefined types, you can also specify the name of
		1115	a package. AnyEvent will try to load the package and then expects to find
		1116	a function named C<anyevent_write_type> inside. If it isn't found, it
		1117	progressively tries to load the parent package until it either finds the
		1118	function (good) or runs out of packages (bad).
		1119
647	Whenever the given C<type> is used, C<push_write> will invoke the code	1120	Whenever the given C<type> is used, C<push_write> will the function with
648	reference with the handle object and the remaining arguments.	1121	the handle object and the remaining arguments.
649		1122
650	The code reference is supposed to return a single octet string that will	1123	The function is supposed to return a single octet string that will be
651	be appended to the write buffer.	1124	appended to the write buffer, so you cna mentally treat this function as a
		1125	"arguments to on-the-wire-format" converter.
652		1126
653	Note that this is a function, and all types registered this way will be	1127	Example: implement a custom write type C<join> that joins the remaining
654	global, so try to use unique names.	1128	arguments using the first one.
		1129
		1130	$handle->push_write (My::Type => " ", 1,2,3);
		1131
		1132	# uses the following package, which can be defined in the "My::Type" or in
		1133	# the "My" modules to be auto-loaded, or just about anywhere when the
		1134	# My::Type::anyevent_write_type is defined before invoking it.
		1135
		1136	package My::Type;
		1137
		1138	sub anyevent_write_type {
		1139	my ($handle, $delim, @args) = @_;
		1140
		1141	join $delim, @args
		1142	}
655		1143
656	=cut	1144	=cut
657		1145
658	#############################################################################	1146	#############################################################################
659		1147
…		…
668	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1156	ways, the "simple" way, using only C<on_read> and the "complex" way, using
669	a queue.	1157	a queue.
670		1158
671	In the simple case, you just install an C<on_read> callback and whenever	1159	In the simple case, you just install an C<on_read> callback and whenever
672	new data arrives, it will be called. You can then remove some data (if	1160	new data arrives, it will be called. You can then remove some data (if
673	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna	1161	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
674	leave the data there if you want to accumulate more (e.g. when only a	1162	leave the data there if you want to accumulate more (e.g. when only a
675	partial message has been received so far).	1163	partial message has been received so far), or change the read queue with
		1164	e.g. C<push_read>.
676		1165
677	In the more complex case, you want to queue multiple callbacks. In this	1166	In the more complex case, you want to queue multiple callbacks. In this
678	case, AnyEvent::Handle will call the first queued callback each time new	1167	case, AnyEvent::Handle will call the first queued callback each time new
679	data arrives (also the first time it is queued) and removes it when it has	1168	data arrives (also the first time it is queued) and remove it when it has
680	done its job (see C<push_read>, below).	1169	done its job (see C<push_read>, below).
681		1170
682	This way you can, for example, push three line-reads, followed by reading	1171	This way you can, for example, push three line-reads, followed by reading
683	a chunk of data, and AnyEvent::Handle will execute them in order.	1172	a chunk of data, and AnyEvent::Handle will execute them in order.
684		1173
…		…
741	=cut	1230	=cut
742		1231
743	sub _drain_rbuf {	1232	sub _drain_rbuf {
744	my ($self) = @_;	1233	my ($self) = @_;
745		1234
		1235	# avoid recursion
		1236	return if $self->{_skip_drain_rbuf};
746	local $self->{_in_drain} = 1;	1237	local $self->{_skip_drain_rbuf} = 1;
747
748	if (
749	defined $self->{rbuf_max}
750	&& $self->{rbuf_max} < length $self->{rbuf}
751	) {
752	$self->_error (&Errno::ENOSPC, 1), return;
753	}
754		1238
755	while () {	1239	while () {
		1240	# we need to use a separate tls read buffer, as we must not receive data while
		1241	# we are draining the buffer, and this can only happen with TLS.
		1242	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1243	if exists $self->{_tls_rbuf};
		1244
756	my $len = length $self->{rbuf};	1245	my $len = length $self->{rbuf};
757		1246
758	if (my $cb = shift @{ $self->{_queue} }) {	1247	if (my $cb = shift @{ $self->{_queue} }) {
759	unless ($cb->($self)) {	1248	unless ($cb->($self)) {
760	if ($self->{_eof}) {	1249	# no progress can be made
761	# no progress can be made (not enough data and no data forthcoming)	1250	# (not enough data and no data forthcoming)
762	$self->_error (&Errno::EPIPE, 1), return;	1251	$self->_error (Errno::EPIPE, 1), return
763	}	1252	if $self->{_eof};
764		1253
765	unshift @{ $self->{_queue} }, $cb;	1254	unshift @{ $self->{_queue} }, $cb;
766	last;	1255	last;
767	}	1256	}
768	} elsif ($self->{on_read}) {	1257	} elsif ($self->{on_read}) {
…		…
775	&& !@{ $self->{_queue} } # and the queue is still empty	1264	&& !@{ $self->{_queue} } # and the queue is still empty
776	&& $self->{on_read} # but we still have on_read	1265	&& $self->{on_read} # but we still have on_read
777	) {	1266	) {
778	# no further data will arrive	1267	# no further data will arrive
779	# so no progress can be made	1268	# so no progress can be made
780	$self->_error (&Errno::EPIPE, 1), return	1269	$self->_error (Errno::EPIPE, 1), return
781	if $self->{_eof};	1270	if $self->{_eof};
782		1271
783	last; # more data might arrive	1272	last; # more data might arrive
784	}	1273	}
785	} else {	1274	} else {
786	# read side becomes idle	1275	# read side becomes idle
787	delete $self->{_rw};	1276	delete $self->{_rw} unless $self->{tls};
788	last;	1277	last;
789	}	1278	}
790	}	1279	}
791		1280
792	if ($self->{_eof}) {	1281	if ($self->{_eof}) {
793	if ($self->{on_eof}) {	1282	$self->{on_eof}
794	$self->{on_eof}($self)	1283	? $self->{on_eof}($self)
795	} else {	1284	: $self->_error (0, 1, "Unexpected end-of-file");
796	$self->_error (0, 1);	1285
797	}	1286	return;
		1287	}
		1288
		1289	if (
		1290	defined $self->{rbuf_max}
		1291	&& $self->{rbuf_max} < length $self->{rbuf}
		1292	) {
		1293	$self->_error (Errno::ENOSPC, 1), return;
798	}	1294	}
799		1295
800	# may need to restart read watcher	1296	# may need to restart read watcher
801	unless ($self->{_rw}) {	1297	unless ($self->{_rw}) {
802	$self->start_read	1298	$self->start_read
…		…
808		1304
809	This replaces the currently set C<on_read> callback, or clears it (when	1305	This replaces the currently set C<on_read> callback, or clears it (when
810	the new callback is C<undef>). See the description of C<on_read> in the	1306	the new callback is C<undef>). See the description of C<on_read> in the
811	constructor.	1307	constructor.
812		1308
		1309	This method may invoke callbacks (and therefore the handle might be
		1310	destroyed after it returns).
		1311
813	=cut	1312	=cut
814		1313
815	sub on_read {	1314	sub on_read {
816	my ($self, $cb) = @_;	1315	my ($self, $cb) = @_;
817		1316
818	$self->{on_read} = $cb;	1317	$self->{on_read} = $cb;
819	$self->_drain_rbuf if $cb && !$self->{_in_drain};	1318	$self->_drain_rbuf if $cb;
820	}	1319	}
821		1320
822	=item $handle->rbuf	1321	=item $handle->rbuf
823		1322
824	Returns the read buffer (as a modifiable lvalue).	1323	Returns the read buffer (as a modifiable lvalue). You can also access the
		1324	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1325	much faster, and no less clean).
825		1326
826	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1327	The only operation allowed on the read buffer (apart from looking at it)
827	you want.	1328	is removing data from its beginning. Otherwise modifying or appending to
		1329	it is not allowed and will lead to hard-to-track-down bugs.
828		1330
829	NOTE: The read buffer should only be used or modified if the C<on_read>,	1331	NOTE: The read buffer should only be used or modified in the C<on_read>
830	C<push_read> or C<unshift_read> methods are used. The other read methods	1332	callback or when C<push_read> or C<unshift_read> are used with a single
831	automatically manage the read buffer.	1333	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1334	will manage the read buffer on their own.
832		1335
833	=cut	1336	=cut
834		1337
835	sub rbuf : lvalue {	1338	sub rbuf : lvalue {
836	$_[0]{rbuf}	1339	$_[0]{rbuf}
…		…
853		1356
854	If enough data was available, then the callback must remove all data it is	1357	If enough data was available, then the callback must remove all data it is
855	interested in (which can be none at all) and return a true value. After returning	1358	interested in (which can be none at all) and return a true value. After returning
856	true, it will be removed from the queue.	1359	true, it will be removed from the queue.
857		1360
		1361	These methods may invoke callbacks (and therefore the handle might be
		1362	destroyed after it returns).
		1363
858	=cut	1364	=cut
859		1365
860	our %RH;	1366	our %RH;
861		1367
862	sub register_read_type($$) {	1368	sub register_read_type($$) {
…		…
868	my $cb = pop;	1374	my $cb = pop;
869		1375
870	if (@_) {	1376	if (@_) {
871	my $type = shift;	1377	my $type = shift;
872		1378
		1379	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
873	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	1380	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
874	->($self, $cb, @_);	1381	->($self, $cb, @_);
875	}	1382	}
876		1383
877	push @{ $self->{_queue} }, $cb;	1384	push @{ $self->{_queue} }, $cb;
878	$self->_drain_rbuf unless $self->{_in_drain};	1385	$self->_drain_rbuf;
879	}	1386	}
880		1387
881	sub unshift_read {	1388	sub unshift_read {
882	my $self = shift;	1389	my $self = shift;
883	my $cb = pop;	1390	my $cb = pop;
884		1391
885	if (@_) {	1392	if (@_) {
886	my $type = shift;	1393	my $type = shift;
887		1394
		1395	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
888	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")	1396	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
889	->($self, $cb, @_);	1397	->($self, $cb, @_);
890	}	1398	}
891		1399
892
893	unshift @{ $self->{_queue} }, $cb;	1400	unshift @{ $self->{_queue} }, $cb;
894	$self->_drain_rbuf unless $self->{_in_drain};	1401	$self->_drain_rbuf;
895	}	1402	}
896		1403
897	=item $handle->push_read (type => @args, $cb)	1404	=item $handle->push_read (type => @args, $cb)
898		1405
899	=item $handle->unshift_read (type => @args, $cb)	1406	=item $handle->unshift_read (type => @args, $cb)
900		1407
901	Instead of providing a callback that parses the data itself you can chose	1408	Instead of providing a callback that parses the data itself you can chose
902	between a number of predefined parsing formats, for chunks of data, lines	1409	between a number of predefined parsing formats, for chunks of data, lines
903	etc.	1410	etc. You can also specify the (fully qualified) name of a package, in
		1411	which case AnyEvent tries to load the package and then expects to find the
		1412	C<anyevent_read_type> function inside (see "custom read types", below).
904		1413
905	Predefined types are (if you have ideas for additional types, feel free to	1414	Predefined types are (if you have ideas for additional types, feel free to
906	drop by and tell us):	1415	drop by and tell us):
907		1416
908	=over 4	1417	=over 4
…		…
1000	the receive buffer when neither C<$accept> nor C<$reject> match,	1509	the receive buffer when neither C<$accept> nor C<$reject> match,
1001	and everything preceding and including the match will be accepted	1510	and everything preceding and including the match will be accepted
1002	unconditionally. This is useful to skip large amounts of data that you	1511	unconditionally. This is useful to skip large amounts of data that you
1003	know cannot be matched, so that the C<$accept> or C<$reject> regex do not	1512	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
1004	have to start matching from the beginning. This is purely an optimisation	1513	have to start matching from the beginning. This is purely an optimisation
1005	and is usually worth only when you expect more than a few kilobytes.	1514	and is usually worth it only when you expect more than a few kilobytes.
1006		1515
1007	Example: expect a http header, which ends at C<\015\012\015\012>. Since we	1516	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
1008	expect the header to be very large (it isn't in practise, but...), we use	1517	expect the header to be very large (it isn't in practice, but...), we use
1009	a skip regex to skip initial portions. The skip regex is tricky in that	1518	a skip regex to skip initial portions. The skip regex is tricky in that
1010	it only accepts something not ending in either \015 or \012, as these are	1519	it only accepts something not ending in either \015 or \012, as these are
1011	required for the accept regex.	1520	required for the accept regex.
1012		1521
1013	$handle->push_read (regex =>	1522	$handle->push_read (regex =>
…		…
1032	return 1;	1541	return 1;
1033	}	1542	}
1034		1543
1035	# reject	1544	# reject
1036	if ($reject && $$rbuf =~ $reject) {	1545	if ($reject && $$rbuf =~ $reject) {
1037	$self->_error (&Errno::EBADMSG);	1546	$self->_error (Errno::EBADMSG);
1038	}	1547	}
1039		1548
1040	# skip	1549	# skip
1041	if ($skip && $$rbuf =~ $skip) {	1550	if ($skip && $$rbuf =~ $skip) {
1042	$data .= substr $$rbuf, 0, $+[0], "";	1551	$data .= substr $$rbuf, 0, $+[0], "";
…		…
1058	my ($self, $cb) = @_;	1567	my ($self, $cb) = @_;
1059		1568
1060	sub {	1569	sub {
1061	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {	1570	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
1062	if ($_[0]{rbuf} =~ /[^0-9]/) {	1571	if ($_[0]{rbuf} =~ /[^0-9]/) {
1063	$self->_error (&Errno::EBADMSG);	1572	$self->_error (Errno::EBADMSG);
1064	}	1573	}
1065	return;	1574	return;
1066	}	1575	}
1067		1576
1068	my $len = $1;	1577	my $len = $1;
…		…
1071	my $string = $_[1];	1580	my $string = $_[1];
1072	$_[0]->unshift_read (chunk => 1, sub {	1581	$_[0]->unshift_read (chunk => 1, sub {
1073	if ($_[1] eq ",") {	1582	if ($_[1] eq ",") {
1074	$cb->($_[0], $string);	1583	$cb->($_[0], $string);
1075	} else {	1584	} else {
1076	$self->_error (&Errno::EBADMSG);	1585	$self->_error (Errno::EBADMSG);
1077	}	1586	}
1078	});	1587	});
1079	});	1588	});
1080		1589
1081	1	1590	1
…		…
1087	An octet string prefixed with an encoded length. The encoding C<$format>	1596	An octet string prefixed with an encoded length. The encoding C<$format>
1088	uses the same format as a Perl C<pack> format, but must specify a single	1597	uses the same format as a Perl C<pack> format, but must specify a single
1089	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an	1598	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
1090	optional C<!>, C<< < >> or C<< > >> modifier).	1599	optional C<!>, C<< < >> or C<< > >> modifier).
1091		1600
1092	DNS over TCP uses a prefix of C<n>, EPP uses a prefix of C<N>.	1601	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1602	EPP uses a prefix of C<N> (4 octtes).
1093		1603
1094	Example: read a block of data prefixed by its length in BER-encoded	1604	Example: read a block of data prefixed by its length in BER-encoded
1095	format (very efficient).	1605	format (very efficient).
1096		1606
1097	$handle->push_read (packstring => "w", sub {	1607	$handle->push_read (packstring => "w", sub {
…		…
1127	}	1637	}
1128	};	1638	};
1129		1639
1130	=item json => $cb->($handle, $hash_or_arrayref)	1640	=item json => $cb->($handle, $hash_or_arrayref)
1131		1641
1132	Reads a JSON object or array, decodes it and passes it to the callback.	1642	Reads a JSON object or array, decodes it and passes it to the
		1643	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
1133		1644
1134	If a C<json> object was passed to the constructor, then that will be used	1645	If a C<json> object was passed to the constructor, then that will be used
1135	for the final decode, otherwise it will create a JSON coder expecting UTF-8.	1646	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
1136		1647
1137	This read type uses the incremental parser available with JSON version	1648	This read type uses the incremental parser available with JSON version
…		…
1146	=cut	1657	=cut
1147		1658
1148	register_read_type json => sub {	1659	register_read_type json => sub {
1149	my ($self, $cb) = @_;	1660	my ($self, $cb) = @_;
1150		1661
1151	require JSON;	1662	my $json = $self->{json} ||= json_coder;
1152		1663
1153	my $data;	1664	my $data;
1154	my $rbuf = \$self->{rbuf};	1665	my $rbuf = \$self->{rbuf};
1155		1666
1156	my $json = $self->{json} ||= JSON->new->utf8;
1157
1158	sub {	1667	sub {
1159	my $ref = $json->incr_parse ($self->{rbuf});	1668	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
1160		1669
1161	if ($ref) {	1670	if ($ref) {
1162	$self->{rbuf} = $json->incr_text;	1671	$self->{rbuf} = $json->incr_text;
1163	$json->incr_text = "";	1672	$json->incr_text = "";
1164	$cb->($self, $ref);	1673	$cb->($self, $ref);
1165		1674
1166	1	1675	1
		1676	} elsif ($@) {
		1677	# error case
		1678	$json->incr_skip;
		1679
		1680	$self->{rbuf} = $json->incr_text;
		1681	$json->incr_text = "";
		1682
		1683	$self->_error (Errno::EBADMSG);
		1684
		1685	()
1167	} else {	1686	} else {
1168	$self->{rbuf} = "";	1687	$self->{rbuf} = "";
		1688
1169	()	1689	()
1170	}	1690	}
1171	}	1691	}
1172	};	1692	};
1173		1693
…		…
1205	# read remaining chunk	1725	# read remaining chunk
1206	$_[0]->unshift_read (chunk => $len, sub {	1726	$_[0]->unshift_read (chunk => $len, sub {
1207	if (my $ref = eval { Storable::thaw ($_[1]) }) {	1727	if (my $ref = eval { Storable::thaw ($_[1]) }) {
1208	$cb->($_[0], $ref);	1728	$cb->($_[0], $ref);
1209	} else {	1729	} else {
1210	$self->_error (&Errno::EBADMSG);	1730	$self->_error (Errno::EBADMSG);
1211	}	1731	}
1212	});	1732	});
1213	}	1733	}
1214		1734
1215	1	1735	1
1216	}	1736	}
1217	};	1737	};
1218		1738
1219	=back	1739	=back
1220		1740
1221	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)	1741	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
1222		1742
1223	This function (not method) lets you add your own types to C<push_read>.	1743	Instead of one of the predefined types, you can also specify the name
		1744	of a package. AnyEvent will try to load the package and then expects to
		1745	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1746	progressively tries to load the parent package until it either finds the
		1747	function (good) or runs out of packages (bad).
1224		1748
1225	Whenever the given C<type> is used, C<push_read> will invoke the code	1749	Whenever this type is used, C<push_read> will invoke the function with the
1226	reference with the handle object, the callback and the remaining	1750	handle object, the original callback and the remaining arguments.
1227	arguments.
1228		1751
1229	The code reference is supposed to return a callback (usually a closure)	1752	The function is supposed to return a callback (usually a closure) that
1230	that works as a plain read callback (see C<< ->push_read ($cb) >>).	1753	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1754	mentally treat the function as a "configurable read type to read callback"
		1755	converter.
1231		1756
1232	It should invoke the passed callback when it is done reading (remember to	1757	It should invoke the original callback when it is done reading (remember
1233	pass C<$handle> as first argument as all other callbacks do that).	1758	to pass C<$handle> as first argument as all other callbacks do that,
		1759	although there is no strict requirement on this).
1234		1760
1235	Note that this is a function, and all types registered this way will be
1236	global, so try to use unique names.
1237
1238	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,	1761	For examples, see the source of this module (F<perldoc -m
1239	search for C<register_read_type>)).	1762	AnyEvent::Handle>, search for C<register_read_type>)).
1240		1763
1241	=item $handle->stop_read	1764	=item $handle->stop_read
1242		1765
1243	=item $handle->start_read	1766	=item $handle->start_read
1244		1767
…		…
1250	Note that AnyEvent::Handle will automatically C<start_read> for you when	1773	Note that AnyEvent::Handle will automatically C<start_read> for you when
1251	you change the C<on_read> callback or push/unshift a read callback, and it	1774	you change the C<on_read> callback or push/unshift a read callback, and it
1252	will automatically C<stop_read> for you when neither C<on_read> is set nor	1775	will automatically C<stop_read> for you when neither C<on_read> is set nor
1253	there are any read requests in the queue.	1776	there are any read requests in the queue.
1254		1777
		1778	These methods will have no effect when in TLS mode (as TLS doesn't support
		1779	half-duplex connections).
		1780
1255	=cut	1781	=cut
1256		1782
1257	sub stop_read {	1783	sub stop_read {
1258	my ($self) = @_;	1784	my ($self) = @_;
1259		1785
1260	delete $self->{_rw};	1786	delete $self->{_rw} unless $self->{tls};
1261	}	1787	}
1262		1788
1263	sub start_read {	1789	sub start_read {
1264	my ($self) = @_;	1790	my ($self) = @_;
1265		1791
1266	unless ($self->{_rw} || $self->{_eof}) {	1792	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
1267	Scalar::Util::weaken $self;	1793	Scalar::Util::weaken $self;
1268		1794
1269	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1795	$self->{_rw} = AE::io $self->{fh}, 0, sub {
1270	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1796	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1271	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1797	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
1272		1798
1273	if ($len > 0) {	1799	if ($len > 0) {
1274	$self->{_activity} = AnyEvent->now;	1800	$self->{_activity} = $self->{_ractivity} = AE::now;
1275		1801
1276	$self->{filter_r}	1802	if ($self->{tls}) {
1277	? $self->{filter_r}($self, $rbuf)	1803	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1278	: $self->{_in_drain} || $self->_drain_rbuf;	1804
		1805	&_dotls ($self);
		1806	} else {
		1807	$self->_drain_rbuf;
		1808	}
		1809
		1810	if ($len == $self->{read_size}) {
		1811	$self->{read_size} *= 2;
		1812	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		1813	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		1814	}
1279		1815
1280	} elsif (defined $len) {	1816	} elsif (defined $len) {
1281	delete $self->{_rw};	1817	delete $self->{_rw};
1282	$self->{_eof} = 1;	1818	$self->{_eof} = 1;
1283	$self->_drain_rbuf unless $self->{_in_drain};	1819	$self->_drain_rbuf;
1284		1820
1285	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {	1821	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
1286	return $self->_error ($!, 1);	1822	return $self->_error ($!, 1);
1287	}	1823	}
1288	});	1824	};
1289	}	1825	}
1290	}	1826	}
1291		1827
		1828	our $ERROR_SYSCALL;
		1829	our $ERROR_WANT_READ;
		1830
		1831	sub _tls_error {
		1832	my ($self, $err) = @_;
		1833
		1834	return $self->_error ($!, 1)
		1835	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1836
		1837	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1838
		1839	# reduce error string to look less scary
		1840	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1841
		1842	if ($self->{_on_starttls}) {
		1843	(delete $self->{_on_starttls})->($self, undef, $err);
		1844	&_freetls;
		1845	} else {
		1846	&_freetls;
		1847	$self->_error (Errno::EPROTO, 1, $err);
		1848	}
		1849	}
		1850
		1851	# poll the write BIO and send the data if applicable
		1852	# also decode read data if possible
		1853	# this is basiclaly our TLS state machine
		1854	# more efficient implementations are possible with openssl,
		1855	# but not with the buggy and incomplete Net::SSLeay.
1292	sub _dotls {	1856	sub _dotls {
1293	my ($self) = @_;	1857	my ($self) = @_;
1294		1858
1295	my $buf;	1859	my $tmp;
1296		1860
1297	if (length $self->{_tls_wbuf}) {	1861	if (length $self->{_tls_wbuf}) {
1298	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {	1862	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
1299	substr $self->{_tls_wbuf}, 0, $len, "";	1863	substr $self->{_tls_wbuf}, 0, $tmp, "";
1300	}	1864	}
1301	}
1302		1865
		1866	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1867	return $self->_tls_error ($tmp)
		1868	if $tmp != $ERROR_WANT_READ
		1869	&& ($tmp != $ERROR_SYSCALL || $!);
		1870	}
		1871
		1872	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1873	unless (length $tmp) {
		1874	$self->{_on_starttls}
		1875	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1876	&_freetls;
		1877
		1878	if ($self->{on_stoptls}) {
		1879	$self->{on_stoptls}($self);
		1880	return;
		1881	} else {
		1882	# let's treat SSL-eof as we treat normal EOF
		1883	delete $self->{_rw};
		1884	$self->{_eof} = 1;
		1885	}
		1886	}
		1887
		1888	$self->{_tls_rbuf} .= $tmp;
		1889	$self->_drain_rbuf;
		1890	$self->{tls} or return; # tls session might have gone away in callback
		1891	}
		1892
		1893	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1894	return $self->_tls_error ($tmp)
		1895	if $tmp != $ERROR_WANT_READ
		1896	&& ($tmp != $ERROR_SYSCALL || $!);
		1897
1303	if (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {	1898	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1304	$self->{wbuf} .= $buf;	1899	$self->{wbuf} .= $tmp;
1305	$self->_drain_wbuf;	1900	$self->_drain_wbuf;
		1901	$self->{tls} or return; # tls session might have gone away in callback
1306	}	1902	}
1307		1903
1308	while (defined ($buf = Net::SSLeay::read ($self->{tls}))) {	1904	$self->{_on_starttls}
1309	if (length $buf) {	1905	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
1310	$self->{rbuf} .= $buf;	1906	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
1311	$self->_drain_rbuf unless $self->{_in_drain};
1312	} else {
1313	# let's treat SSL-eof as we treat normal EOF
1314	$self->{_eof} = 1;
1315	$self->_shutdown;
1316	return;
1317	}
1318	}
1319
1320	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
1321
1322	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
1323	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
1324	return $self->_error ($!, 1);
1325	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
1326	return $self->_error (&Errno::EIO, 1);
1327	}
1328
1329	# all others are fine for our purposes
1330	}
1331	}	1907	}
1332		1908
1333	=item $handle->starttls ($tls[, $tls_ctx])	1909	=item $handle->starttls ($tls[, $tls_ctx])
1334		1910
1335	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1911	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
1336	object is created, you can also do that at a later time by calling	1912	object is created, you can also do that at a later time by calling
1337	C<starttls>.	1913	C<starttls>.
1338		1914
		1915	Starting TLS is currently an asynchronous operation - when you push some
		1916	write data and then call C<< ->starttls >> then TLS negotiation will start
		1917	immediately, after which the queued write data is then sent.
		1918
1339	The first argument is the same as the C<tls> constructor argument (either	1919	The first argument is the same as the C<tls> constructor argument (either
1340	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1920	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
1341		1921
1342	The second argument is the optional C<Net::SSLeay::CTX> object that is	1922	The second argument is the optional C<AnyEvent::TLS> object that is used
1343	used when AnyEvent::Handle has to create its own TLS connection object.	1923	when AnyEvent::Handle has to create its own TLS connection object, or
		1924	a hash reference with C<< key => value >> pairs that will be used to
		1925	construct a new context.
1344		1926
1345	The TLS connection object will end up in C<< $handle->{tls} >> after this	1927	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
1346	call and can be used or changed to your liking. Note that the handshake	1928	context in C<< $handle->{tls_ctx} >> after this call and can be used or
1347	might have already started when this function returns.	1929	changed to your liking. Note that the handshake might have already started
		1930	when this function returns.
1348		1931
		1932	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1933	handshakes on the same stream. It is best to not attempt to use the
		1934	stream after stopping TLS.
		1935
		1936	This method may invoke callbacks (and therefore the handle might be
		1937	destroyed after it returns).
		1938
1349	=cut	1939	=cut
		1940
		1941	our %TLS_CACHE; #TODO not yet documented, should we?
1350		1942
1351	sub starttls {	1943	sub starttls {
1352	my ($self, $ssl, $ctx) = @_;	1944	my ($self, $tls, $ctx) = @_;
1353		1945
1354	$self->stoptls;	1946	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1947	if $self->{tls};
1355		1948
1356	if ($ssl eq "accept") {	1949	$self->{tls} = $tls;
1357	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1950	$self->{tls_ctx} = $ctx if @_ > 2;
1358	Net::SSLeay::set_accept_state ($ssl);	1951
1359	} elsif ($ssl eq "connect") {	1952	return unless $self->{fh};
1360	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1953
1361	Net::SSLeay::set_connect_state ($ssl);	1954	require Net::SSLeay;
		1955
		1956	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1957	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1958
		1959	$tls = delete $self->{tls};
		1960	$ctx = $self->{tls_ctx};
		1961
		1962	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1963
		1964	if ("HASH" eq ref $ctx) {
		1965	require AnyEvent::TLS;
		1966
		1967	if ($ctx->{cache}) {
		1968	my $key = $ctx+0;
		1969	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1970	} else {
		1971	$ctx = new AnyEvent::TLS %$ctx;
		1972	}
		1973	}
1362	}	1974
1363		1975	$self->{tls_ctx} = $ctx || TLS_CTX ();
1364	$self->{tls} = $ssl;	1976	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
1365		1977
1366	# basically, this is deep magic (because SSL_read should have the same issues)	1978	# basically, this is deep magic (because SSL_read should have the same issues)
1367	# but the openssl maintainers basically said: "trust us, it just works".	1979	# but the openssl maintainers basically said: "trust us, it just works".
1368	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1980	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
1369	# and mismaintained ssleay-module doesn't even offer them).	1981	# and mismaintained ssleay-module doesn't even offer them).
1370	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1982	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1983	#
		1984	# in short: this is a mess.
		1985	#
		1986	# note that we do not try to keep the length constant between writes as we are required to do.
		1987	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1988	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1989	# have identity issues in that area.
1371	Net::SSLeay::CTX_set_mode ($self->{tls},	1990	# Net::SSLeay::CTX_set_mode ($ssl,
1372	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	1991	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
1373	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	1992	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1993	Net::SSLeay::CTX_set_mode ($tls, 1|2);
1374		1994
1375	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1995	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1376	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1996	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1377		1997
		1998	Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf});
		1999
1378	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});	2000	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
1379		2001
1380	$self->{filter_w} = sub {	2002	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
1381	$_[0]{_tls_wbuf} .= ${$_[1]};	2003	if $self->{on_starttls};
1382	&_dotls;	2004
1383	};	2005	&_dotls; # need to trigger the initial handshake
1384	$self->{filter_r} = sub {	2006	$self->start_read; # make sure we actually do read
1385	Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
1386	&_dotls;
1387	};
1388	}	2007	}
1389		2008
1390	=item $handle->stoptls	2009	=item $handle->stoptls
1391		2010
1392	Destroys the SSL connection, if any. Partial read or write data will be	2011	Shuts down the SSL connection - this makes a proper EOF handshake by
1393	lost.	2012	sending a close notify to the other side, but since OpenSSL doesn't
		2013	support non-blocking shut downs, it is not guaranteed that you can re-use
		2014	the stream afterwards.
		2015
		2016	This method may invoke callbacks (and therefore the handle might be
		2017	destroyed after it returns).
1394		2018
1395	=cut	2019	=cut
1396		2020
1397	sub stoptls {	2021	sub stoptls {
1398	my ($self) = @_;	2022	my ($self) = @_;
1399		2023
1400	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	2024	if ($self->{tls} && $self->{fh}) {
		2025	Net::SSLeay::shutdown ($self->{tls});
1401		2026
1402	delete $self->{_rbio};	2027	&_dotls;
1403	delete $self->{_wbio};	2028
1404	delete $self->{_tls_wbuf};	2029	# # we don't give a shit. no, we do, but we can't. no...#d#
1405	delete $self->{filter_r};	2030	# # we, we... have to use openssl :/#d#
1406	delete $self->{filter_w};	2031	# &_freetls;#d#
		2032	}
		2033	}
		2034
		2035	sub _freetls {
		2036	my ($self) = @_;
		2037
		2038	return unless $self->{tls};
		2039
		2040	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2041	if $self->{tls} > 0;
		2042
		2043	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
1407	}	2044	}
1408		2045
1409	sub DESTROY {	2046	sub DESTROY {
1410	my $self = shift;	2047	my ($self) = @_;
1411		2048
1412	$self->stoptls;	2049	&_freetls;
1413		2050
1414	my $linger = exists $self->{linger} ? $self->{linger} : 3600;	2051	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
1415		2052
1416	if ($linger && length $self->{wbuf}) {	2053	if ($linger && length $self->{wbuf} && $self->{fh}) {
1417	my $fh = delete $self->{fh};	2054	my $fh = delete $self->{fh};
1418	my $wbuf = delete $self->{wbuf};	2055	my $wbuf = delete $self->{wbuf};
1419		2056
1420	my @linger;	2057	my @linger;
1421		2058
1422	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {	2059	push @linger, AE::io $fh, 1, sub {
1423	my $len = syswrite $fh, $wbuf, length $wbuf;	2060	my $len = syswrite $fh, $wbuf, length $wbuf;
1424		2061
1425	if ($len > 0) {	2062	if ($len > 0) {
1426	substr $wbuf, 0, $len, "";	2063	substr $wbuf, 0, $len, "";
1427	} else {	2064	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
1428	@linger = (); # end	2065	@linger = (); # end
1429	}	2066	}
		2067	};
		2068	push @linger, AE::timer $linger, 0, sub {
		2069	@linger = ();
		2070	};
		2071	}
		2072	}
		2073
		2074	=item $handle->destroy
		2075
		2076	Shuts down the handle object as much as possible - this call ensures that
		2077	no further callbacks will be invoked and as many resources as possible
		2078	will be freed. Any method you will call on the handle object after
		2079	destroying it in this way will be silently ignored (and it will return the
		2080	empty list).
		2081
		2082	Normally, you can just "forget" any references to an AnyEvent::Handle
		2083	object and it will simply shut down. This works in fatal error and EOF
		2084	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2085	callback, so when you want to destroy the AnyEvent::Handle object from
		2086	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2087	that case.
		2088
		2089	Destroying the handle object in this way has the advantage that callbacks
		2090	will be removed as well, so if those are the only reference holders (as
		2091	is common), then one doesn't need to do anything special to break any
		2092	reference cycles.
		2093
		2094	The handle might still linger in the background and write out remaining
		2095	data, as specified by the C<linger> option, however.
		2096
		2097	=cut
		2098
		2099	sub destroy {
		2100	my ($self) = @_;
		2101
		2102	$self->DESTROY;
		2103	%$self = ();
		2104	bless $self, "AnyEvent::Handle::destroyed";
		2105	}
		2106
		2107	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2108	#nop
		2109	}
		2110
		2111	=item $handle->destroyed
		2112
		2113	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2114	->destroy >>, true otherwise.
		2115
		2116	Can be useful to decide whether the handle is still valid after some
		2117	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2118	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2119	can destroy the handle, so work can be avoided by checking sometimes:
		2120
		2121	$hdl->starttls ("accept");
		2122	return if $hdl->destroyed;
		2123	$hdl->push_write (...
		2124
		2125	Note that the call to C<push_write> will silently be ignored if the handle
		2126	has been destroyed, so often you can just ignore the possibility of the
		2127	handle being destroyed.
		2128
		2129	=cut
		2130
		2131	sub destroyed { 0 }
		2132	sub AnyEvent::Handle::destroyed::destroyed { 1 }
		2133
		2134	=item AnyEvent::Handle::TLS_CTX
		2135
		2136	This function creates and returns the AnyEvent::TLS object used by default
		2137	for TLS mode.
		2138
		2139	The context is created by calling L<AnyEvent::TLS> without any arguments.
		2140
		2141	=cut
		2142
		2143	our $TLS_CTX;
		2144
		2145	sub TLS_CTX() {
		2146	$TLS_CTX ||= do {
		2147	require AnyEvent::TLS;
		2148
		2149	new AnyEvent::TLS
		2150	}
		2151	}
		2152
		2153	=back
		2154
		2155
		2156	=head1 NONFREQUENTLY ASKED QUESTIONS
		2157
		2158	=over 4
		2159
		2160	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2161	still get further invocations!
		2162
		2163	That's because AnyEvent::Handle keeps a reference to itself when handling
		2164	read or write callbacks.
		2165
		2166	It is only safe to "forget" the reference inside EOF or error callbacks,
		2167	from within all other callbacks, you need to explicitly call the C<<
		2168	->destroy >> method.
		2169
		2170	=item Why is my C<on_eof> callback never called?
		2171
		2172	Probably because your C<on_error> callback is being called instead: When
		2173	you have outstanding requests in your read queue, then an EOF is
		2174	considered an error as you clearly expected some data.
		2175
		2176	To avoid this, make sure you have an empty read queue whenever your handle
		2177	is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
		2178	an C<on_read> handler that simply pushes the first read requests in the
		2179	queue.
		2180
		2181	See also the next question, which explains this in a bit more detail.
		2182
		2183	=item How can I serve requests in a loop?
		2184
		2185	Most protocols consist of some setup phase (authentication for example)
		2186	followed by a request handling phase, where the server waits for requests
		2187	and handles them, in a loop.
		2188
		2189	There are two important variants: The first (traditional, better) variant
		2190	handles requests until the server gets some QUIT command, causing it to
		2191	close the connection first (highly desirable for a busy TCP server). A
		2192	client dropping the connection is an error, which means this variant can
		2193	detect an unexpected detection close.
		2194
		2195	To handle this case, always make sure you have a on-empty read queue, by
		2196	pushing the "read request start" handler on it:
		2197
		2198	# we assume a request starts with a single line
		2199	my @start_request; @start_request = (line => sub {
		2200	my ($hdl, $line) = @_;
		2201
		2202	... handle request
		2203
		2204	# push next request read, possibly from a nested callback
		2205	$hdl->push_read (@start_request);
		2206	});
		2207
		2208	# auth done, now go into request handling loop
		2209	# now push the first @start_request
		2210	$hdl->push_read (@start_request);
		2211
		2212	By always having an outstanding C<push_read>, the handle always expects
		2213	some data and raises the C<EPIPE> error when the connction is dropped
		2214	unexpectedly.
		2215
		2216	The second variant is a protocol where the client can drop the connection
		2217	at any time. For TCP, this means that the server machine may run out of
		2218	sockets easier, and in general, it means you cnanot distinguish a protocl
		2219	failure/client crash from a normal connection close. Nevertheless, these
		2220	kinds of protocols are common (and sometimes even the best solution to the
		2221	problem).
		2222
		2223	Having an outstanding read request at all times is possible if you ignore
		2224	C<EPIPE> errors, but this doesn't help with when the client drops the
		2225	connection during a request, which would still be an error.
		2226
		2227	A better solution is to push the initial request read in an C<on_read>
		2228	callback. This avoids an error, as when the server doesn't expect data
		2229	(i.e. is idly waiting for the next request, an EOF will not raise an
		2230	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2231	and simpler:
		2232
		2233	# auth done, now go into request handling loop
		2234	$hdl->on_read (sub {
		2235	my ($hdl) = @_;
		2236
		2237	# called each time we receive data but the read queue is empty
		2238	# simply start read the request
		2239
		2240	$hdl->push_read (line => sub {
		2241	my ($hdl, $line) = @_;
		2242
		2243	... handle request
		2244
		2245	# do nothing special when the request has been handled, just
		2246	# let the request queue go empty.
1430	});	2247	});
1431	push @linger, AnyEvent->timer (after => $linger, cb => sub {
1432	@linger = ();
1433	});	2248	});
		2249
		2250	=item I get different callback invocations in TLS mode/Why can't I pause
		2251	reading?
		2252
		2253	Unlike, say, TCP, TLS connections do not consist of two independent
		2254	communication channels, one for each direction. Or put differently, the
		2255	read and write directions are not independent of each other: you cannot
		2256	write data unless you are also prepared to read, and vice versa.
		2257
		2258	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2259	callback invocations when you are not expecting any read data - the reason
		2260	is that AnyEvent::Handle always reads in TLS mode.
		2261
		2262	During the connection, you have to make sure that you always have a
		2263	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2264	connection (or when you no longer want to use it) you can call the
		2265	C<destroy> method.
		2266
		2267	=item How do I read data until the other side closes the connection?
		2268
		2269	If you just want to read your data into a perl scalar, the easiest way
		2270	to achieve this is by setting an C<on_read> callback that does nothing,
		2271	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2272	will be in C<$_[0]{rbuf}>:
		2273
		2274	$handle->on_read (sub { });
		2275	$handle->on_eof (undef);
		2276	$handle->on_error (sub {
		2277	my $data = delete $_[0]{rbuf};
		2278	});
		2279
		2280	The reason to use C<on_error> is that TCP connections, due to latencies
		2281	and packets loss, might get closed quite violently with an error, when in
		2282	fact all data has been received.
		2283
		2284	It is usually better to use acknowledgements when transferring data,
		2285	to make sure the other side hasn't just died and you got the data
		2286	intact. This is also one reason why so many internet protocols have an
		2287	explicit QUIT command.
		2288
		2289	=item I don't want to destroy the handle too early - how do I wait until
		2290	all data has been written?
		2291
		2292	After writing your last bits of data, set the C<on_drain> callback
		2293	and destroy the handle in there - with the default setting of
		2294	C<low_water_mark> this will be called precisely when all data has been
		2295	written to the socket:
		2296
		2297	$handle->push_write (...);
		2298	$handle->on_drain (sub {
		2299	warn "all data submitted to the kernel\n";
		2300	undef $handle;
		2301	});
		2302
		2303	If you just want to queue some data and then signal EOF to the other side,
		2304	consider using C<< ->push_shutdown >> instead.
		2305
		2306	=item I want to contact a TLS/SSL server, I don't care about security.
		2307
		2308	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2309	connect to it and then create the AnyEvent::Handle with the C<tls>
		2310	parameter:
		2311
		2312	tcp_connect $host, $port, sub {
		2313	my ($fh) = @_;
		2314
		2315	my $handle = new AnyEvent::Handle
		2316	fh => $fh,
		2317	tls => "connect",
		2318	on_error => sub { ... };
		2319
		2320	$handle->push_write (...);
1434	}	2321	};
1435	}
1436		2322
1437	=item AnyEvent::Handle::TLS_CTX	2323	=item I want to contact a TLS/SSL server, I do care about security.
1438		2324
1439	This function creates and returns the Net::SSLeay::CTX object used by	2325	Then you should additionally enable certificate verification, including
1440	default for TLS mode.	2326	peername verification, if the protocol you use supports it (see
		2327	L<AnyEvent::TLS>, C<verify_peername>).
1441		2328
1442	The context is created like this:	2329	E.g. for HTTPS:
1443		2330
1444	Net::SSLeay::load_error_strings;	2331	tcp_connect $host, $port, sub {
1445	Net::SSLeay::SSLeay_add_ssl_algorithms;	2332	my ($fh) = @_;
1446	Net::SSLeay::randomize;
1447		2333
1448	my $CTX = Net::SSLeay::CTX_new;	2334	my $handle = new AnyEvent::Handle
		2335	fh => $fh,
		2336	peername => $host,
		2337	tls => "connect",
		2338	tls_ctx => { verify => 1, verify_peername => "https" },
		2339	...
1449		2340
1450	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL	2341	Note that you must specify the hostname you connected to (or whatever
		2342	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2343	peername verification will be done.
1451		2344
1452	=cut	2345	The above will use the system-dependent default set of trusted CA
		2346	certificates. If you want to check against a specific CA, add the
		2347	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
1453		2348
1454	our $TLS_CTX;	2349	tls_ctx => {
		2350	verify => 1,
		2351	verify_peername => "https",
		2352	ca_file => "my-ca-cert.pem",
		2353	},
1455		2354
1456	sub TLS_CTX() {	2355	=item I want to create a TLS/SSL server, how do I do that?
1457	$TLS_CTX || do {
1458	require Net::SSLeay;
1459		2356
1460	Net::SSLeay::load_error_strings ();	2357	Well, you first need to get a server certificate and key. You have
1461	Net::SSLeay::SSLeay_add_ssl_algorithms ();	2358	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
1462	Net::SSLeay::randomize ();	2359	self-signed certificate (cheap. check the search engine of your choice,
		2360	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2361	nice program for that purpose).
1463		2362
1464	$TLS_CTX = Net::SSLeay::CTX_new ();	2363	Then create a file with your private key (in PEM format, see
		2364	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2365	file should then look like this:
1465		2366
1466	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());	2367	-----BEGIN RSA PRIVATE KEY-----
		2368	...header data
		2369	... lots of base64'y-stuff
		2370	-----END RSA PRIVATE KEY-----
1467		2371
1468	$TLS_CTX	2372	-----BEGIN CERTIFICATE-----
1469	}	2373	... lots of base64'y-stuff
1470	}	2374	-----END CERTIFICATE-----
		2375
		2376	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2377	specify this file as C<cert_file>:
		2378
		2379	tcp_server undef, $port, sub {
		2380	my ($fh) = @_;
		2381
		2382	my $handle = new AnyEvent::Handle
		2383	fh => $fh,
		2384	tls => "accept",
		2385	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2386	...
		2387
		2388	When you have intermediate CA certificates that your clients might not
		2389	know about, just append them to the C<cert_file>.
1471		2390
1472	=back	2391	=back
		2392
1473		2393
1474	=head1 SUBCLASSING AnyEvent::Handle	2394	=head1 SUBCLASSING AnyEvent::Handle
1475		2395
1476	In many cases, you might want to subclass AnyEvent::Handle.	2396	In many cases, you might want to subclass AnyEvent::Handle.
1477		2397
…		…
1494		2414
1495	=item * all members not documented here and not prefixed with an underscore	2415	=item * all members not documented here and not prefixed with an underscore
1496	are free to use in subclasses.	2416	are free to use in subclasses.
1497		2417
1498	Of course, new versions of AnyEvent::Handle may introduce more "public"	2418	Of course, new versions of AnyEvent::Handle may introduce more "public"
1499	member variables, but thats just life, at least it is documented.	2419	member variables, but that's just life. At least it is documented.
1500		2420
1501	=back	2421	=back
1502		2422
1503	=head1 AUTHOR	2423	=head1 AUTHOR
1504		2424

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