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

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict 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 = 4.22;
20		4
21	=head1 SYNOPSIS	5	=head1 SYNOPSIS
22		6
23	use AnyEvent;	7	use AnyEvent;
24	use AnyEvent::Handle;	8	use AnyEvent::Handle;
25		9
26	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
27		11
28	my $handle =	12	my $hdl; $hdl = new AnyEvent::Handle
29	AnyEvent::Handle->new (
30	fh => \*STDIN,	13	fh => \*STDIN,
31	on_eof => sub {	14	on_error => sub {
32	$cv->broadcast;	15	my ($hdl, $fatal, $msg) = @_;
33	},	16	warn "got error $msg\n";
		17	$hdl->destroy;
		18	$cv->send;
34	);	19	};
35		20
36	# send some request line	21	# send some request line
37	$handle->push_write ("getinfo\015\012");	22	$hdl->push_write ("getinfo\015\012");
38		23
39	# read the response line	24	# read the response line
40	$handle->push_read (line => sub {	25	$hdl->push_read (line => sub {
41	my ($handle, $line) = @_;	26	my ($hdl, $line) = @_;
42	warn "read line <$line>\n";	27	warn "got line <$line>\n";
43	$cv->send;	28	$cv->send;
44	});	29	});
45		30
46	$cv->recv;	31	$cv->recv;
47		32
48	=head1 DESCRIPTION	33	=head1 DESCRIPTION
49		34
50	This module is a helper module to make it easier to do event-based I/O on	35	This is a helper module to make it easier to do event-based I/O on
51	filehandles. For utility functions for doing non-blocking connects and accepts	36	stream-based filehandles (sockets, pipes, and other stream things).
52	on sockets see L<AnyEvent::Util>.
53		37
		38	The L<AnyEvent::Intro> tutorial contains some well-documented
		39	AnyEvent::Handle examples.
		40
54	In the following, when the documentation refers to of "bytes" then this	41	In the following, where the documentation refers to "bytes", it means
55	means characters. As sysread and syswrite are used for all I/O, their	42	characters. As sysread and syswrite are used for all I/O, their
56	treatment of characters applies to this module as well.	43	treatment of characters applies to this module as well.
		44
		45	At the very minimum, you should specify C<fh> or C<connect>, and the
		46	C<on_error> callback.
57		47
58	All callbacks will be invoked with the handle object as their first	48	All callbacks will be invoked with the handle object as their first
59	argument.	49	argument.
60		50
		51	=cut
		52
		53	package AnyEvent::Handle;
		54
		55	use Scalar::Util ();
		56	use List::Util ();
		57	use Carp ();
		58	use Errno qw(EAGAIN EINTR);
		59
		60	use AnyEvent (); BEGIN { AnyEvent::common_sense }
		61	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		62
		63	our $VERSION = $AnyEvent::VERSION;
		64
		65	sub _load_func($) {
		66	my $func = $_[0];
		67
		68	unless (defined &$func) {
		69	my $pkg = $func;
		70	do {
		71	$pkg =~ s/::[^:]+$//
		72	or return;
		73	eval "require $pkg";
		74	} until defined &$func;
		75	}
		76
		77	\&$func
		78	}
		79
		80	sub MAX_READ_SIZE() { 131072 }
		81
61	=head1 METHODS	82	=head1 METHODS
62		83
63	=over 4	84	=over 4
64		85
65	=item B<new (%args)>	86	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
66		87
67	The constructor supports these arguments (all as key => value pairs).	88	The constructor supports these arguments (all as C<< key => value >> pairs).
68		89
69	=over 4	90	=over 4
70		91
71	=item fh => $filehandle [MANDATORY]	92	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
72		93
73	The filehandle this L<AnyEvent::Handle> object will operate on.	94	The filehandle this L<AnyEvent::Handle> object will operate on.
74
75	NOTE: The filehandle will be set to non-blocking (using	95	NOTE: The filehandle will be set to non-blocking mode (using
76	AnyEvent::Util::fh_nonblocking).	96	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		97	that mode.
77		98
		99	=item connect => [$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
78	=item on_eof => $cb->($handle)	116	=item on_prepare => $cb->($handle)
79		117
80	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
81	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
82	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).
83		123
84	While not mandatory, it is highly recommended to set an eof callback,	124	The return value of this callback should be the connect timeout value in
85	otherwise you might end up with a closed socket while you are still	125	seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
86	waiting for data.	126	default timeout is to be used).
87		127
		128	=item on_connect => $cb->($handle, $host, $port, $retry->())
		129
		130	This callback is called when a connection has been successfully established.
		131
		132	The peer's numeric host and port (the socket peername) are passed as
		133	parameters, together with a retry callback.
		134
		135	If, for some reason, the handle is not acceptable, calling C<$retry>
		136	will continue with the next connection target (in case of multi-homed
		137	hosts or SRV records there can be multiple connection endpoints). At the
		138	time it is called the read and write queues, eof status, tls status and
		139	similar properties of the handle will have been reset.
		140
		141	In most cases, you should ignore the C<$retry> parameter.
		142
		143	=item on_connect_error => $cb->($handle, $message)
		144
		145	This callback is called when the connection could not be
		146	established. C<$!> will contain the relevant error code, and C<$message> a
		147	message describing it (usually the same as C<"$!">).
		148
		149	If this callback isn't specified, then C<on_error> will be called with a
		150	fatal error instead.
		151
		152	=back
		153
88	=item on_error => $cb->($handle, $fatal)	154	=item on_error => $cb->($handle, $fatal, $message)
89		155
90	This is the error callback, which is called when, well, some error	156	This is the error callback, which is called when, well, some error
91	occured, such as not being able to resolve the hostname, failure to	157	occured, such as not being able to resolve the hostname, failure to
92	connect or a read error.	158	connect, or a read error.
93		159
94	Some errors are fatal (which is indicated by C<$fatal> being true). On	160	Some errors are fatal (which is indicated by C<$fatal> being true). On
95	fatal errors the handle object will be shut down and will not be	161	fatal errors the handle object will be destroyed (by a call to C<< ->
		162	destroy >>) after invoking the error callback (which means you are free to
		163	examine the handle object). Examples of fatal errors are an EOF condition
		164	with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
		165	cases where the other side can close the connection at will, it is
		166	often easiest to not report C<EPIPE> errors in this callback.
		167
		168	AnyEvent::Handle tries to find an appropriate error code for you to check
		169	against, but in some cases (TLS errors), this does not work well. It is
		170	recommended to always output the C<$message> argument in human-readable
		171	error messages (it's usually the same as C<"$!">).
		172
96	usable. Non-fatal errors can be retried by simply returning, but it is	173	Non-fatal errors can be retried by returning, but it is recommended
97	recommended to simply ignore this parameter and instead abondon the handle	174	to simply ignore this parameter and instead abondon the handle object
98	object when this callback is invoked.	175	when this callback is invoked. Examples of non-fatal errors are timeouts
		176	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
99		177
100	On callback entrance, the value of C<$!> contains the operating system	178	On entry to the callback, the value of C<$!> contains the operating
101	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>).
102		181
103	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
104	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
105	C<croak>.	184	C<croak>.
106		185
107	=item on_read => $cb->($handle)	186	=item on_read => $cb->($handle)
108		187
109	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
110	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
111	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
112	read buffer).	191	read buffer).
113		192
114	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 >>
115	method or access the C<$handle->{rbuf}> member directly.	194	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		195	must not enlarge or modify the read buffer, you can only remove data at
		196	the beginning from it.
116		197
		198	You can also call C<< ->push_read (...) >> or any other function that
		199	modifies the read queue. Or do both. Or ...
		200
117	When an EOF condition is detected then AnyEvent::Handle will first try to	201	When an EOF condition is detected, AnyEvent::Handle will first try to
118	feed all the remaining data to the queued callbacks and C<on_read> before	202	feed all the remaining data to the queued callbacks and C<on_read> before
119	calling the C<on_eof> callback. If no progress can be made, then a fatal	203	calling the C<on_eof> callback. If no progress can be made, then a fatal
120	error will be raised (with C<$!> set to C<EPIPE>).	204	error will be raised (with C<$!> set to C<EPIPE>).
121		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
122	=item on_drain => $cb->($handle)	227	=item on_drain => $cb->($handle)
123		228
124	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
125	(or when the callback is set and the buffer is empty already).	230	(or immediately if the buffer is empty already).
126		231
127	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.
128		233
129	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
130	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
…		…
132	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
133	the file when the write queue becomes empty.	238	the file when the write queue becomes empty.
134		239
135	=item timeout => $fractional_seconds	240	=item timeout => $fractional_seconds
136		241
		242	=item rtimeout => $fractional_seconds
		243
		244	=item wtimeout => $fractional_seconds
		245
137	If non-zero, then this enables an "inactivity" timeout: whenever this many	246	If non-zero, then these enables an "inactivity" timeout: whenever this
138	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
139	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
140	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).
141		251
		252	There are three variants of the timeouts that work independently of each
		253	other, for both read and write (triggered when nothing was read I<OR>
		254	written), just read (triggered when nothing was read), and just write:
		255	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		256	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		257	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		258
142	Note that timeout processing is also active when you currently do not have	259	Note that timeout processing is active even when you do not have any
143	any outstanding read or write requests: If you plan to keep the connection	260	outstanding read or write requests: If you plan to keep the connection
144	idle then you should disable the timout temporarily or ignore the timeout	261	idle then you should disable the timeout temporarily or ignore the
145	in the C<on_timeout> callback.	262	timeout in the corresponding C<on_timeout> callback, in which case
		263	AnyEvent::Handle will simply restart the timeout.
146		264
147	Zero (the default) disables this timeout.	265	Zero (the default) disables the corresponding timeout.
148		266
149	=item on_timeout => $cb->($handle)	267	=item on_timeout => $cb->($handle)
		268
		269	=item on_rtimeout => $cb->($handle)
		270
		271	=item on_wtimeout => $cb->($handle)
150		272
151	Called whenever the inactivity timeout passes. If you return from this	273	Called whenever the inactivity timeout passes. If you return from this
152	callback, then the timeout will be reset as if some activity had happened,	274	callback, then the timeout will be reset as if some activity had happened,
153	so this condition is not fatal in any way.	275	so this condition is not fatal in any way.
154		276
155	=item rbuf_max => <bytes>	277	=item rbuf_max => <bytes>
156		278
157	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	279	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
158	when the read buffer ever (strictly) exceeds this size. This is useful to	280	when the read buffer ever (strictly) exceeds this size. This is useful to
159	avoid denial-of-service attacks.	281	avoid some forms of denial-of-service attacks.
160		282
161	For example, a server accepting connections from untrusted sources should	283	For example, a server accepting connections from untrusted sources should
162	be configured to accept only so-and-so much data that it cannot act on	284	be configured to accept only so-and-so much data that it cannot act on
163	(for example, when expecting a line, an attacker could send an unlimited	285	(for example, when expecting a line, an attacker could send an unlimited
164	amount of data without a callback ever being called as long as the line	286	amount of data without a callback ever being called as long as the line
165	isn't finished).	287	isn't finished).
166		288
		289	=item wbuf_max => <bytes>
		290
		291	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		292	when the write buffer ever (strictly) exceeds this size. This is useful to
		293	avoid some forms of denial-of-service attacks.
		294
		295	Although the units of this parameter is bytes, this is the I<raw> number
		296	of bytes not yet accepted by the kernel. This can make a difference when
		297	you e.g. use TLS, as TLS typically makes your write data larger (but it
		298	can also make it smaller due to compression).
		299
		300	As an example of when this limit is useful, take a chat server that sends
		301	chat messages to a client. If the client does not read those in a timely
		302	manner then the send buffer in the server would grow unbounded.
		303
167	=item autocork => <boolean>	304	=item autocork => <boolean>
168		305
169	When disabled (the default), then C<push_write> will try to immediately	306	When disabled (the default), C<push_write> will try to immediately
170	write the data to the handle if possible. This avoids having to register	307	write the data to the handle if possible. This avoids having to register
171	a write watcher and wait for the next event loop iteration, but can be	308	a write watcher and wait for the next event loop iteration, but can
172	inefficient if you write multiple small chunks (this disadvantage is	309	be inefficient if you write multiple small chunks (on the wire, this
173	usually avoided by your kernel's nagle algorithm, see C<low_delay>).	310	disadvantage is usually avoided by your kernel's nagle algorithm, see
		311	C<no_delay>, but this option can save costly syscalls).
174		312
175	When enabled, then writes will always be queued till the next event loop	313	When enabled, writes will always be queued till the next event loop
176	iteration. This is efficient when you do many small writes per iteration,	314	iteration. This is efficient when you do many small writes per iteration,
177	but less efficient when you do a single write only.	315	but less efficient when you do a single write only per iteration (or when
		316	the write buffer often is full). It also increases write latency.
178		317
179	=item no_delay => <boolean>	318	=item no_delay => <boolean>
180		319
181	When doing small writes on sockets, your operating system kernel might	320	When doing small writes on sockets, your operating system kernel might
182	wait a bit for more data before actually sending it out. This is called	321	wait a bit for more data before actually sending it out. This is called
183	the Nagle algorithm, and usually it is beneficial.	322	the Nagle algorithm, and usually it is beneficial.
184		323
185	In some situations you want as low a delay as possible, which cna be	324	In some situations you want as low a delay as possible, which can be
186	accomplishd by setting this option to true.	325	accomplishd by setting this option to a true value.
187		326
188	The default is your opertaing system's default behaviour, this option	327	The default is your operating system's default behaviour (most likely
189	explicitly enables or disables it, if possible.	328	enabled). This option explicitly enables or disables it, if possible.
		329
		330	=item keepalive => <boolean>
		331
		332	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		333	normally, TCP connections have no time-out once established, so TCP
		334	connections, once established, can stay alive forever even when the other
		335	side has long gone. TCP keepalives are a cheap way to take down long-lived
		336	TCP connections when the other side becomes unreachable. While the default
		337	is OS-dependent, TCP keepalives usually kick in after around two hours,
		338	and, if the other side doesn't reply, take down the TCP connection some 10
		339	to 15 minutes later.
		340
		341	It is harmless to specify this option for file handles that do not support
		342	keepalives, and enabling it on connections that are potentially long-lived
		343	is usually a good idea.
		344
		345	=item oobinline => <boolean>
		346
		347	BSD majorly fucked up the implementation of TCP urgent data. The result
		348	is that almost no OS implements TCP according to the specs, and every OS
		349	implements it slightly differently.
		350
		351	If you want to handle TCP urgent data, then setting this flag (the default
		352	is enabled) gives you the most portable way of getting urgent data, by
		353	putting it into the stream.
		354
		355	Since BSD emulation of OOB data on top of TCP's urgent data can have
		356	security implications, AnyEvent::Handle sets this flag automatically
		357	unless explicitly specified. Note that setting this flag after
		358	establishing a connection I<may> be a bit too late (data loss could
		359	already have occured on BSD systems), but at least it will protect you
		360	from most attacks.
190		361
191	=item read_size => <bytes>	362	=item read_size => <bytes>
192		363
193	The default read block size (the amount of bytes this module will try to read	364	The initial read block size, the number of bytes this module will try to
194	during each (loop iteration). Default: C<8192>.	365	read during each loop iteration. Each handle object will consume at least
		366	this amount of memory for the read buffer as well, so when handling many
		367	connections requirements). See also C<max_read_size>. Default: C<2048>.
		368
		369	=item max_read_size => <bytes>
		370
		371	The maximum read buffer size used by the dynamic adjustment
		372	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		373	one go it will double C<read_size> up to the maximum given by this
		374	option. Default: C<131072> or C<read_size>, whichever is higher.
195		375
196	=item low_water_mark => <bytes>	376	=item low_water_mark => <bytes>
197		377
198	Sets the amount of bytes (default: C<0>) that make up an "empty" write	378	Sets the number of bytes (default: C<0>) that make up an "empty" write
199	buffer: If the write reaches this size or gets even samller it is	379	buffer: If the buffer reaches this size or gets even samller it is
200	considered empty.	380	considered empty.
201		381
		382	Sometimes it can be beneficial (for performance reasons) to add data to
		383	the write buffer before it is fully drained, but this is a rare case, as
		384	the operating system kernel usually buffers data as well, so the default
		385	is good in almost all cases.
		386
202	=item linger => <seconds>	387	=item linger => <seconds>
203		388
204	If non-zero (default: C<3600>), then the destructor of the	389	If this is non-zero (default: C<3600>), the destructor of the
205	AnyEvent::Handle object will check wether there is still outstanding write	390	AnyEvent::Handle object will check whether there is still outstanding
206	data and will install a watcher that will write out this data. No errors	391	write data and will install a watcher that will write this data to the
207	will be reported (this mostly matches how the operating system treats	392	socket. No errors will be reported (this mostly matches how the operating
208	outstanding data at socket close time).	393	system treats outstanding data at socket close time).
209		394
210	This will not work for partial TLS data that could not yet been	395	This will not work for partial TLS data that could not be encoded
211	encoded. This data will be lost.	396	yet. This data will be lost. Calling the C<stoptls> method in time might
		397	help.
		398
		399	=item peername => $string
		400
		401	A string used to identify the remote site - usually the DNS hostname
		402	(I<not> IDN!) used to create the connection, rarely the IP address.
		403
		404	Apart from being useful in error messages, this string is also used in TLS
		405	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		406	verification will be skipped when C<peername> is not specified or is
		407	C<undef>.
212		408
213	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	409	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
214		410
215	When this parameter is given, it enables TLS (SSL) mode, that means it	411	When this parameter is given, it enables TLS (SSL) mode, that means
216	will start making tls handshake and will transparently encrypt/decrypt	412	AnyEvent will start a TLS handshake as soon as the connection has been
217	data.	413	established and will transparently encrypt/decrypt data afterwards.
		414
		415	All TLS protocol errors will be signalled as C<EPROTO>, with an
		416	appropriate error message.
218		417
219	TLS mode requires Net::SSLeay to be installed (it will be loaded	418	TLS mode requires Net::SSLeay to be installed (it will be loaded
220	automatically when you try to create a TLS handle).	419	automatically when you try to create a TLS handle): this module doesn't
		420	have a dependency on that module, so if your module requires it, you have
		421	to add the dependency yourself.
221		422
222	For the TLS server side, use C<accept>, and for the TLS client side of a	423	Unlike TCP, TLS has a server and client side: for the TLS server side, use
223	connection, use C<connect> mode.	424	C<accept>, and for the TLS client side of a connection, use C<connect>
		425	mode.
224		426
225	You can also provide your own TLS connection object, but you have	427	You can also provide your own TLS connection object, but you have
226	to make sure that you call either C<Net::SSLeay::set_connect_state>	428	to make sure that you call either C<Net::SSLeay::set_connect_state>
227	or C<Net::SSLeay::set_accept_state> on it before you pass it to	429	or C<Net::SSLeay::set_accept_state> on it before you pass it to
228	AnyEvent::Handle.	430	AnyEvent::Handle. Also, this module will take ownership of this connection
		431	object.
229		432
		433	At some future point, AnyEvent::Handle might switch to another TLS
		434	implementation, then the option to use your own session object will go
		435	away.
		436
		437	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		438	passing in the wrong integer will lead to certain crash. This most often
		439	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		440	segmentation fault.
		441
230	See the C<starttls> method if you need to start TLS negotiation later.	442	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
231		443
232	=item tls_ctx => $ssl_ctx	444	=item tls_ctx => $anyevent_tls
233		445
234	Use the given Net::SSLeay::CTX object to create the new TLS connection	446	Use the given C<AnyEvent::TLS> object to create the new TLS connection
235	(unless a connection object was specified directly). If this parameter is	447	(unless a connection object was specified directly). If this
236	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	448	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		449	C<AnyEvent::Handle::TLS_CTX>.
		450
		451	Instead of an object, you can also specify a hash reference with C<< key
		452	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		453	new TLS context object.
		454
		455	=item on_starttls => $cb->($handle, $success[, $error_message])
		456
		457	This callback will be invoked when the TLS/SSL handshake has finished. If
		458	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		459	(C<on_stoptls> will not be called in this case).
		460
		461	The session in C<< $handle->{tls} >> can still be examined in this
		462	callback, even when the handshake was not successful.
		463
		464	TLS handshake failures will not cause C<on_error> to be invoked when this
		465	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		466
		467	Without this callback, handshake failures lead to C<on_error> being
		468	called as usual.
		469
		470	Note that you cannot just call C<starttls> again in this callback. If you
		471	need to do that, start an zero-second timer instead whose callback can
		472	then call C<< ->starttls >> again.
		473
		474	=item on_stoptls => $cb->($handle)
		475
		476	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		477	set, then it will be invoked after freeing the TLS session. If it is not,
		478	then a TLS shutdown condition will be treated like a normal EOF condition
		479	on the handle.
		480
		481	The session in C<< $handle->{tls} >> can still be examined in this
		482	callback.
		483
		484	This callback will only be called on TLS shutdowns, not when the
		485	underlying handle signals EOF.
237		486
238	=item json => JSON or JSON::XS object	487	=item json => JSON or JSON::XS object
239		488
240	This is the json coder object used by the C<json> read and write types.	489	This is the json coder object used by the C<json> read and write types.
241		490
242	If you don't supply it, then AnyEvent::Handle will create and use a	491	If you don't supply it, then AnyEvent::Handle will create and use a
243	suitable one, which will write and expect UTF-8 encoded JSON texts.	492	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		493	texts.
244		494
245	Note that you are responsible to depend on the JSON module if you want to	495	Note that you are responsible to depend on the JSON module if you want to
246	use this functionality, as AnyEvent does not have a dependency itself.	496	use this functionality, as AnyEvent does not have a dependency itself.
247		497
248	=item filter_r => $cb
249
250	=item filter_w => $cb
251
252	These exist, but are undocumented at this time.
253
254	=back	498	=back
255		499
256	=cut	500	=cut
257		501
258	sub new {	502	sub new {
259	my $class = shift;	503	my $class = shift;
260
261	my $self = bless { @_ }, $class;	504	my $self = bless { @_ }, $class;
262		505
263	$self->{fh} or Carp::croak "mandatory argument fh is missing";	506	if ($self->{fh}) {
		507	$self->_start;
		508	return unless $self->{fh}; # could be gone by now
		509
		510	} elsif ($self->{connect}) {
		511	require AnyEvent::Socket;
		512
		513	$self->{peername} = $self->{connect}[0]
		514	unless exists $self->{peername};
		515
		516	$self->{_skip_drain_rbuf} = 1;
		517
		518	{
		519	Scalar::Util::weaken (my $self = $self);
		520
		521	$self->{_connect} =
		522	AnyEvent::Socket::tcp_connect (
		523	$self->{connect}[0],
		524	$self->{connect}[1],
		525	sub {
		526	my ($fh, $host, $port, $retry) = @_;
		527
		528	delete $self->{_connect}; # no longer needed
		529
		530	if ($fh) {
		531	$self->{fh} = $fh;
		532
		533	delete $self->{_skip_drain_rbuf};
		534	$self->_start;
		535
		536	$self->{on_connect}
		537	and $self->{on_connect}($self, $host, $port, sub {
		538	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		539	$self->{_skip_drain_rbuf} = 1;
		540	&$retry;
		541	});
		542
		543	} else {
		544	if ($self->{on_connect_error}) {
		545	$self->{on_connect_error}($self, "$!");
		546	$self->destroy if $self;
		547	} else {
		548	$self->_error ($!, 1);
		549	}
		550	}
		551	},
		552	sub {
		553	local $self->{fh} = $_[0];
		554
		555	$self->{on_prepare}
		556	? $self->{on_prepare}->($self)
		557	: ()
		558	}
		559	);
		560	}
		561
		562	} else {
		563	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		564	}
		565
		566	$self
		567	}
		568
		569	sub _start {
		570	my ($self) = @_;
		571
		572	# too many clueless people try to use udp and similar sockets
		573	# with AnyEvent::Handle, do them a favour.
		574	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		575	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		576	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
264		577
265	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	578	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
266		579
267	if ($self->{tls}) {	580	$self->{_activity} =
268	require Net::SSLeay;	581	$self->{_ractivity} =
		582	$self->{_wactivity} = AE::now;
		583
		584	$self->{read_size} ||= 2048;
		585	$self->{max_read_size} = $self->{read_size}
		586	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		587
		588	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		589	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		590	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		591
		592	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		593	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		594
		595	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		596
269	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	597	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
270	}	598	if $self->{tls};
271		599
272	$self->{_activity} = AnyEvent->now;
273	$self->_timeout;
274
275	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};	600	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
276	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
277		601
278	$self->start_read	602	$self->start_read
279	if $self->{on_read};	603	if $self->{on_read} || @{ $self->{_queue} };
280		604
281	$self	605	$self->_drain_wbuf;
282	}
283
284	sub _shutdown {
285	my ($self) = @_;
286
287	delete $self->{_tw};
288	delete $self->{_rw};
289	delete $self->{_ww};
290	delete $self->{fh};
291
292	$self->stoptls;
293	}	606	}
294		607
295	sub _error {	608	sub _error {
296	my ($self, $errno, $fatal) = @_;	609	my ($self, $errno, $fatal, $message) = @_;
297
298	$self->_shutdown
299	if $fatal;
300		610
301	$! = $errno;	611	$! = $errno;
		612	$message ||= "$!";
302		613
303	if ($self->{on_error}) {	614	if ($self->{on_error}) {
304	$self->{on_error}($self, $fatal);	615	$self->{on_error}($self, $fatal, $message);
305	} else {	616	$self->destroy if $fatal;
		617	} elsif ($self->{fh} || $self->{connect}) {
		618	$self->destroy;
306	Carp::croak "AnyEvent::Handle uncaught error: $!";	619	Carp::croak "AnyEvent::Handle uncaught error: $message";
307	}	620	}
308	}	621	}
309		622
310	=item $fh = $handle->fh	623	=item $fh = $handle->fh
311		624
312	This method returns the file handle of the L<AnyEvent::Handle> object.	625	This method returns the file handle used to create the L<AnyEvent::Handle> object.
313		626
314	=cut	627	=cut
315		628
316	sub fh { $_[0]{fh} }	629	sub fh { $_[0]{fh} }
317		630
…		…
335	$_[0]{on_eof} = $_[1];	648	$_[0]{on_eof} = $_[1];
336	}	649	}
337		650
338	=item $handle->on_timeout ($cb)	651	=item $handle->on_timeout ($cb)
339		652
340	Replace the current C<on_timeout> callback, or disables the callback	653	=item $handle->on_rtimeout ($cb)
341	(but not the timeout) if C<$cb> = C<undef>. See C<timeout> constructor
342	argument.
343		654
344	=cut	655	=item $handle->on_wtimeout ($cb)
345		656
346	sub on_timeout {	657	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
347	$_[0]{on_timeout} = $_[1];	658	callback, or disables the callback (but not the timeout) if C<$cb> =
348	}	659	C<undef>. See the C<timeout> constructor argument and method.
		660
		661	=cut
		662
		663	# see below
349		664
350	=item $handle->autocork ($boolean)	665	=item $handle->autocork ($boolean)
351		666
352	Enables or disables the current autocork behaviour (see C<autocork>	667	Enables or disables the current autocork behaviour (see C<autocork>
353	constructor argument).	668	constructor argument). Changes will only take effect on the next write.
354		669
355	=cut	670	=cut
		671
		672	sub autocork {
		673	$_[0]{autocork} = $_[1];
		674	}
356		675
357	=item $handle->no_delay ($boolean)	676	=item $handle->no_delay ($boolean)
358		677
359	Enables or disables the C<no_delay> setting (see constructor argument of	678	Enables or disables the C<no_delay> setting (see constructor argument of
360	the same name for details).	679	the same name for details).
…		…
362	=cut	681	=cut
363		682
364	sub no_delay {	683	sub no_delay {
365	$_[0]{no_delay} = $_[1];	684	$_[0]{no_delay} = $_[1];
366		685
		686	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		687	if $_[0]{fh};
		688	}
		689
		690	=item $handle->keepalive ($boolean)
		691
		692	Enables or disables the C<keepalive> setting (see constructor argument of
		693	the same name for details).
		694
		695	=cut
		696
		697	sub keepalive {
		698	$_[0]{keepalive} = $_[1];
		699
367	eval {	700	eval {
368	local $SIG{__DIE__};	701	local $SIG{__DIE__};
369	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];	702	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		703	if $_[0]{fh};
370	};	704	};
371	}	705	}
372		706
		707	=item $handle->oobinline ($boolean)
		708
		709	Enables or disables the C<oobinline> setting (see constructor argument of
		710	the same name for details).
		711
		712	=cut
		713
		714	sub oobinline {
		715	$_[0]{oobinline} = $_[1];
		716
		717	eval {
		718	local $SIG{__DIE__};
		719	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		720	if $_[0]{fh};
		721	};
		722	}
		723
		724	=item $handle->keepalive ($boolean)
		725
		726	Enables or disables the C<keepalive> setting (see constructor argument of
		727	the same name for details).
		728
		729	=cut
		730
		731	sub keepalive {
		732	$_[0]{keepalive} = $_[1];
		733
		734	eval {
		735	local $SIG{__DIE__};
		736	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		737	if $_[0]{fh};
		738	};
		739	}
		740
		741	=item $handle->on_starttls ($cb)
		742
		743	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		744
		745	=cut
		746
		747	sub on_starttls {
		748	$_[0]{on_starttls} = $_[1];
		749	}
		750
		751	=item $handle->on_stoptls ($cb)
		752
		753	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		754
		755	=cut
		756
		757	sub on_stoptls {
		758	$_[0]{on_stoptls} = $_[1];
		759	}
		760
		761	=item $handle->rbuf_max ($max_octets)
		762
		763	Configures the C<rbuf_max> setting (C<undef> disables it).
		764
		765	=item $handle->wbuf_max ($max_octets)
		766
		767	Configures the C<wbuf_max> setting (C<undef> disables it).
		768
		769	=cut
		770
		771	sub rbuf_max {
		772	$_[0]{rbuf_max} = $_[1];
		773	}
		774
		775	sub wbuf_max {
		776	$_[0]{wbuf_max} = $_[1];
		777	}
		778
373	#############################################################################	779	#############################################################################
374		780
375	=item $handle->timeout ($seconds)	781	=item $handle->timeout ($seconds)
376		782
		783	=item $handle->rtimeout ($seconds)
		784
		785	=item $handle->wtimeout ($seconds)
		786
377	Configures (or disables) the inactivity timeout.	787	Configures (or disables) the inactivity timeout.
378		788
379	=cut	789	The timeout will be checked instantly, so this method might destroy the
		790	handle before it returns.
380		791
381	sub timeout {	792	=item $handle->timeout_reset
		793
		794	=item $handle->rtimeout_reset
		795
		796	=item $handle->wtimeout_reset
		797
		798	Reset the activity timeout, as if data was received or sent.
		799
		800	These methods are cheap to call.
		801
		802	=cut
		803
		804	for my $dir ("", "r", "w") {
		805	my $timeout = "${dir}timeout";
		806	my $tw = "_${dir}tw";
		807	my $on_timeout = "on_${dir}timeout";
		808	my $activity = "_${dir}activity";
		809	my $cb;
		810
		811	*$on_timeout = sub {
		812	$_[0]{$on_timeout} = $_[1];
		813	};
		814
		815	*$timeout = sub {
382	my ($self, $timeout) = @_;	816	my ($self, $new_value) = @_;
383		817
		818	$new_value >= 0
		819	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		820
384	$self->{timeout} = $timeout;	821	$self->{$timeout} = $new_value;
385	$self->_timeout;	822	delete $self->{$tw}; &$cb;
386	}	823	};
387		824
		825	*{"${dir}timeout_reset"} = sub {
		826	$_[0]{$activity} = AE::now;
		827	};
		828
		829	# main workhorse:
388	# reset the timeout watcher, as neccessary	830	# reset the timeout watcher, as neccessary
389	# also check for time-outs	831	# also check for time-outs
390	sub _timeout {	832	$cb = sub {
391	my ($self) = @_;	833	my ($self) = @_;
392		834
393	if ($self->{timeout}) {	835	if ($self->{$timeout} && $self->{fh}) {
394	my $NOW = AnyEvent->now;	836	my $NOW = AE::now;
395		837
396	# when would the timeout trigger?	838	# when would the timeout trigger?
397	my $after = $self->{_activity} + $self->{timeout} - $NOW;	839	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
398		840
399	# now or in the past already?	841	# now or in the past already?
400	if ($after <= 0) {	842	if ($after <= 0) {
401	$self->{_activity} = $NOW;	843	$self->{$activity} = $NOW;
402		844
403	if ($self->{on_timeout}) {	845	if ($self->{$on_timeout}) {
404	$self->{on_timeout}($self);	846	$self->{$on_timeout}($self);
405	} else {	847	} else {
406	$self->_error (&Errno::ETIMEDOUT);	848	$self->_error (Errno::ETIMEDOUT);
		849	}
		850
		851	# callback could have changed timeout value, optimise
		852	return unless $self->{$timeout};
		853
		854	# calculate new after
		855	$after = $self->{$timeout};
407	}	856	}
408		857
409	# callback could have changed timeout value, optimise	858	Scalar::Util::weaken $self;
410	return unless $self->{timeout};	859	return unless $self; # ->error could have destroyed $self
411		860
412	# calculate new after	861	$self->{$tw} ||= AE::timer $after, 0, sub {
413	$after = $self->{timeout};	862	delete $self->{$tw};
		863	$cb->($self);
		864	};
		865	} else {
		866	delete $self->{$tw};
414	}	867	}
415
416	Scalar::Util::weaken $self;
417	return unless $self; # ->error could have destroyed $self
418
419	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
420	delete $self->{_tw};
421	$self->_timeout;
422	});
423	} else {
424	delete $self->{_tw};
425	}	868	}
426	}	869	}
427		870
428	#############################################################################	871	#############################################################################
429		872
…		…
445	=item $handle->on_drain ($cb)	888	=item $handle->on_drain ($cb)
446		889
447	Sets the C<on_drain> callback or clears it (see the description of	890	Sets the C<on_drain> callback or clears it (see the description of
448	C<on_drain> in the constructor).	891	C<on_drain> in the constructor).
449		892
		893	This method may invoke callbacks (and therefore the handle might be
		894	destroyed after it returns).
		895
450	=cut	896	=cut
451		897
452	sub on_drain {	898	sub on_drain {
453	my ($self, $cb) = @_;	899	my ($self, $cb) = @_;
454		900
455	$self->{on_drain} = $cb;	901	$self->{on_drain} = $cb;
456		902
457	$cb->($self)	903	$cb->($self)
458	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	904	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
459	}	905	}
460		906
461	=item $handle->push_write ($data)	907	=item $handle->push_write ($data)
462		908
463	Queues the given scalar to be written. You can push as much data as you	909	Queues the given scalar to be written. You can push as much data as
464	want (only limited by the available memory), as C<AnyEvent::Handle>	910	you want (only limited by the available memory and C<wbuf_max>), as
465	buffers it independently of the kernel.	911	C<AnyEvent::Handle> buffers it independently of the kernel.
		912
		913	This method may invoke callbacks (and therefore the handle might be
		914	destroyed after it returns).
466		915
467	=cut	916	=cut
468		917
469	sub _drain_wbuf {	918	sub _drain_wbuf {
470	my ($self) = @_;	919	my ($self) = @_;
…		…
474	Scalar::Util::weaken $self;	923	Scalar::Util::weaken $self;
475		924
476	my $cb = sub {	925	my $cb = sub {
477	my $len = syswrite $self->{fh}, $self->{wbuf};	926	my $len = syswrite $self->{fh}, $self->{wbuf};
478		927
479	if ($len >= 0) {	928	if (defined $len) {
480	substr $self->{wbuf}, 0, $len, "";	929	substr $self->{wbuf}, 0, $len, "";
481		930
482	$self->{_activity} = AnyEvent->now;	931	$self->{_activity} = $self->{_wactivity} = AE::now;
483		932
484	$self->{on_drain}($self)	933	$self->{on_drain}($self)
485	if $self->{low_water_mark} >= length $self->{wbuf}	934	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
486	&& $self->{on_drain};	935	&& $self->{on_drain};
487		936
488	delete $self->{_ww} unless length $self->{wbuf};	937	delete $self->{_ww} unless length $self->{wbuf};
489	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {	938	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
490	$self->_error ($!, 1);	939	$self->_error ($!, 1);
…		…
493		942
494	# try to write data immediately	943	# try to write data immediately
495	$cb->() unless $self->{autocork};	944	$cb->() unless $self->{autocork};
496		945
497	# if still data left in wbuf, we need to poll	946	# if still data left in wbuf, we need to poll
498	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)	947	$self->{_ww} = AE::io $self->{fh}, 1, $cb
499	if length $self->{wbuf};	948	if length $self->{wbuf};
		949
		950	if (
		951	defined $self->{wbuf_max}
		952	&& $self->{wbuf_max} < length $self->{wbuf}
		953	) {
		954	$self->_error (Errno::ENOSPC, 1), return;
		955	}
500	};	956	};
501	}	957	}
502		958
503	our %WH;	959	our %WH;
504		960
		961	# deprecated
505	sub register_write_type($$) {	962	sub register_write_type($$) {
506	$WH{$_[0]} = $_[1];	963	$WH{$_[0]} = $_[1];
507	}	964	}
508		965
509	sub push_write {	966	sub push_write {
510	my $self = shift;	967	my $self = shift;
511		968
512	if (@_ > 1) {	969	if (@_ > 1) {
513	my $type = shift;	970	my $type = shift;
514		971
		972	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
515	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	973	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
516	->($self, @_);	974	->($self, @_);
517	}	975	}
518		976
		977	# we downgrade here to avoid hard-to-track-down bugs,
		978	# and diagnose the problem earlier and better.
		979
519	if ($self->{filter_w}) {	980	if ($self->{tls}) {
520	$self->{filter_w}($self, \$_[0]);	981	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		982	&_dotls ($self) if $self->{fh};
521	} else {	983	} else {
522	$self->{wbuf} .= $_[0];	984	utf8::downgrade $self->{wbuf} .= $_[0];
523	$self->_drain_wbuf;	985	$self->_drain_wbuf if $self->{fh};
524	}	986	}
525	}	987	}
526		988
527	=item $handle->push_write (type => @args)	989	=item $handle->push_write (type => @args)
528		990
529	Instead of formatting your data yourself, you can also let this module do	991	Instead of formatting your data yourself, you can also let this module
530	the job by specifying a type and type-specific arguments.	992	do the job by specifying a type and type-specific arguments. You
		993	can also specify the (fully qualified) name of a package, in which
		994	case AnyEvent tries to load the package and then expects to find the
		995	C<anyevent_write_type> function inside (see "custom write types", below).
531		996
532	Predefined types are (if you have ideas for additional types, feel free to	997	Predefined types are (if you have ideas for additional types, feel free to
533	drop by and tell us):	998	drop by and tell us):
534		999
535	=over 4	1000	=over 4
…		…
542	=cut	1007	=cut
543		1008
544	register_write_type netstring => sub {	1009	register_write_type netstring => sub {
545	my ($self, $string) = @_;	1010	my ($self, $string) = @_;
546		1011
547	sprintf "%d:%s,", (length $string), $string	1012	(length $string) . ":$string,"
548	};	1013	};
549		1014
550	=item packstring => $format, $data	1015	=item packstring => $format, $data
551		1016
552	An octet string prefixed with an encoded length. The encoding C<$format>	1017	An octet string prefixed with an encoded length. The encoding C<$format>
…		…
592	Other languages could read single lines terminated by a newline and pass	1057	Other languages could read single lines terminated by a newline and pass
593	this line into their JSON decoder of choice.	1058	this line into their JSON decoder of choice.
594		1059
595	=cut	1060	=cut
596		1061
		1062	sub json_coder() {
		1063	eval { require JSON::XS; JSON::XS->new->utf8 }
		1064	|| do { require JSON; JSON->new->utf8 }
		1065	}
		1066
597	register_write_type json => sub {	1067	register_write_type json => sub {
598	my ($self, $ref) = @_;	1068	my ($self, $ref) = @_;
599		1069
600	require JSON;	1070	my $json = $self->{json} ||= json_coder;
601		1071
602	$self->{json} ? $self->{json}->encode ($ref)	1072	$json->encode ($ref)
603	: JSON::encode_json ($ref)
604	};	1073	};
605		1074
606	=item storable => $reference	1075	=item storable => $reference
607		1076
608	Freezes the given reference using L<Storable> and writes it to the	1077	Freezes the given reference using L<Storable> and writes it to the
…		…
618	pack "w/a*", Storable::nfreeze ($ref)	1087	pack "w/a*", Storable::nfreeze ($ref)
619	};	1088	};
620		1089
621	=back	1090	=back
622		1091
623	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)	1092	=item $handle->push_shutdown
624		1093
625	This function (not method) lets you add your own types to C<push_write>.	1094	Sometimes you know you want to close the socket after writing your data
		1095	before it was actually written. One way to do that is to replace your
		1096	C<on_drain> handler by a callback that shuts down the socket (and set
		1097	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1098	replaces the C<on_drain> callback with:
		1099
		1100	sub { shutdown $_[0]{fh}, 1 }
		1101
		1102	This simply shuts down the write side and signals an EOF condition to the
		1103	the peer.
		1104
		1105	You can rely on the normal read queue and C<on_eof> handling
		1106	afterwards. This is the cleanest way to close a connection.
		1107
		1108	This method may invoke callbacks (and therefore the handle might be
		1109	destroyed after it returns).
		1110
		1111	=cut
		1112
		1113	sub push_shutdown {
		1114	my ($self) = @_;
		1115
		1116	delete $self->{low_water_mark};
		1117	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1118	}
		1119
		1120	=item custom write types - Package::anyevent_write_type $handle, @args
		1121
		1122	Instead of one of the predefined types, you can also specify the name of
		1123	a package. AnyEvent will try to load the package and then expects to find
		1124	a function named C<anyevent_write_type> inside. If it isn't found, it
		1125	progressively tries to load the parent package until it either finds the
		1126	function (good) or runs out of packages (bad).
		1127
626	Whenever the given C<type> is used, C<push_write> will invoke the code	1128	Whenever the given C<type> is used, C<push_write> will the function with
627	reference with the handle object and the remaining arguments.	1129	the handle object and the remaining arguments.
628		1130
629	The code reference is supposed to return a single octet string that will	1131	The function is supposed to return a single octet string that will be
630	be appended to the write buffer.	1132	appended to the write buffer, so you cna mentally treat this function as a
		1133	"arguments to on-the-wire-format" converter.
631		1134
632	Note that this is a function, and all types registered this way will be	1135	Example: implement a custom write type C<join> that joins the remaining
633	global, so try to use unique names.	1136	arguments using the first one.
		1137
		1138	$handle->push_write (My::Type => " ", 1,2,3);
		1139
		1140	# uses the following package, which can be defined in the "My::Type" or in
		1141	# the "My" modules to be auto-loaded, or just about anywhere when the
		1142	# My::Type::anyevent_write_type is defined before invoking it.
		1143
		1144	package My::Type;
		1145
		1146	sub anyevent_write_type {
		1147	my ($handle, $delim, @args) = @_;
		1148
		1149	join $delim, @args
		1150	}
634		1151
635	=cut	1152	=cut
636		1153
637	#############################################################################	1154	#############################################################################
638		1155
…		…
647	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1164	ways, the "simple" way, using only C<on_read> and the "complex" way, using
648	a queue.	1165	a queue.
649		1166
650	In the simple case, you just install an C<on_read> callback and whenever	1167	In the simple case, you just install an C<on_read> callback and whenever
651	new data arrives, it will be called. You can then remove some data (if	1168	new data arrives, it will be called. You can then remove some data (if
652	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna	1169	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
653	leave the data there if you want to accumulate more (e.g. when only a	1170	leave the data there if you want to accumulate more (e.g. when only a
654	partial message has been received so far).	1171	partial message has been received so far), or change the read queue with
		1172	e.g. C<push_read>.
655		1173
656	In the more complex case, you want to queue multiple callbacks. In this	1174	In the more complex case, you want to queue multiple callbacks. In this
657	case, AnyEvent::Handle will call the first queued callback each time new	1175	case, AnyEvent::Handle will call the first queued callback each time new
658	data arrives (also the first time it is queued) and removes it when it has	1176	data arrives (also the first time it is queued) and remove it when it has
659	done its job (see C<push_read>, below).	1177	done its job (see C<push_read>, below).
660		1178
661	This way you can, for example, push three line-reads, followed by reading	1179	This way you can, for example, push three line-reads, followed by reading
662	a chunk of data, and AnyEvent::Handle will execute them in order.	1180	a chunk of data, and AnyEvent::Handle will execute them in order.
663		1181
…		…
720	=cut	1238	=cut
721		1239
722	sub _drain_rbuf {	1240	sub _drain_rbuf {
723	my ($self) = @_;	1241	my ($self) = @_;
724		1242
		1243	# avoid recursion
		1244	return if $self->{_skip_drain_rbuf};
725	local $self->{_in_drain} = 1;	1245	local $self->{_skip_drain_rbuf} = 1;
726
727	if (
728	defined $self->{rbuf_max}
729	&& $self->{rbuf_max} < length $self->{rbuf}
730	) {
731	return $self->_error (&Errno::ENOSPC, 1);
732	}
733		1246
734	while () {	1247	while () {
		1248	# we need to use a separate tls read buffer, as we must not receive data while
		1249	# we are draining the buffer, and this can only happen with TLS.
		1250	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1251	if exists $self->{_tls_rbuf};
		1252
735	my $len = length $self->{rbuf};	1253	my $len = length $self->{rbuf};
736		1254
737	if (my $cb = shift @{ $self->{_queue} }) {	1255	if (my $cb = shift @{ $self->{_queue} }) {
738	unless ($cb->($self)) {	1256	unless ($cb->($self)) {
739	if ($self->{_eof}) {	1257	# no progress can be made
740	# no progress can be made (not enough data and no data forthcoming)	1258	# (not enough data and no data forthcoming)
741	$self->_error (&Errno::EPIPE, 1), last;	1259	$self->_error (Errno::EPIPE, 1), return
742	}	1260	if $self->{_eof};
743		1261
744	unshift @{ $self->{_queue} }, $cb;	1262	unshift @{ $self->{_queue} }, $cb;
745	last;	1263	last;
746	}	1264	}
747	} elsif ($self->{on_read}) {	1265	} elsif ($self->{on_read}) {
…		…
754	&& !@{ $self->{_queue} } # and the queue is still empty	1272	&& !@{ $self->{_queue} } # and the queue is still empty
755	&& $self->{on_read} # but we still have on_read	1273	&& $self->{on_read} # but we still have on_read
756	) {	1274	) {
757	# no further data will arrive	1275	# no further data will arrive
758	# so no progress can be made	1276	# so no progress can be made
759	$self->_error (&Errno::EPIPE, 1), last	1277	$self->_error (Errno::EPIPE, 1), return
760	if $self->{_eof};	1278	if $self->{_eof};
761		1279
762	last; # more data might arrive	1280	last; # more data might arrive
763	}	1281	}
764	} else {	1282	} else {
765	# read side becomes idle	1283	# read side becomes idle
766	delete $self->{_rw};	1284	delete $self->{_rw} unless $self->{tls};
767	last;	1285	last;
768	}	1286	}
769	}	1287	}
770		1288
		1289	if ($self->{_eof}) {
		1290	$self->{on_eof}
771	$self->{on_eof}($self)	1291	? $self->{on_eof}($self)
772	if $self->{_eof} && $self->{on_eof};	1292	: $self->_error (0, 1, "Unexpected end-of-file");
		1293
		1294	return;
		1295	}
		1296
		1297	if (
		1298	defined $self->{rbuf_max}
		1299	&& $self->{rbuf_max} < length $self->{rbuf}
		1300	) {
		1301	$self->_error (Errno::ENOSPC, 1), return;
		1302	}
773		1303
774	# may need to restart read watcher	1304	# may need to restart read watcher
775	unless ($self->{_rw}) {	1305	unless ($self->{_rw}) {
776	$self->start_read	1306	$self->start_read
777	if $self->{on_read} || @{ $self->{_queue} };	1307	if $self->{on_read} || @{ $self->{_queue} };
…		…
782		1312
783	This replaces the currently set C<on_read> callback, or clears it (when	1313	This replaces the currently set C<on_read> callback, or clears it (when
784	the new callback is C<undef>). See the description of C<on_read> in the	1314	the new callback is C<undef>). See the description of C<on_read> in the
785	constructor.	1315	constructor.
786		1316
		1317	This method may invoke callbacks (and therefore the handle might be
		1318	destroyed after it returns).
		1319
787	=cut	1320	=cut
788		1321
789	sub on_read {	1322	sub on_read {
790	my ($self, $cb) = @_;	1323	my ($self, $cb) = @_;
791		1324
792	$self->{on_read} = $cb;	1325	$self->{on_read} = $cb;
793	$self->_drain_rbuf if $cb && !$self->{_in_drain};	1326	$self->_drain_rbuf if $cb;
794	}	1327	}
795		1328
796	=item $handle->rbuf	1329	=item $handle->rbuf
797		1330
798	Returns the read buffer (as a modifiable lvalue).	1331	Returns the read buffer (as a modifiable lvalue). You can also access the
		1332	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1333	much faster, and no less clean).
799		1334
800	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1335	The only operation allowed on the read buffer (apart from looking at it)
801	you want.	1336	is removing data from its beginning. Otherwise modifying or appending to
		1337	it is not allowed and will lead to hard-to-track-down bugs.
802		1338
803	NOTE: The read buffer should only be used or modified if the C<on_read>,	1339	NOTE: The read buffer should only be used or modified in the C<on_read>
804	C<push_read> or C<unshift_read> methods are used. The other read methods	1340	callback or when C<push_read> or C<unshift_read> are used with a single
805	automatically manage the read buffer.	1341	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1342	will manage the read buffer on their own.
806		1343
807	=cut	1344	=cut
808		1345
809	sub rbuf : lvalue {	1346	sub rbuf : lvalue {
810	$_[0]{rbuf}	1347	$_[0]{rbuf}
…		…
827		1364
828	If enough data was available, then the callback must remove all data it is	1365	If enough data was available, then the callback must remove all data it is
829	interested in (which can be none at all) and return a true value. After returning	1366	interested in (which can be none at all) and return a true value. After returning
830	true, it will be removed from the queue.	1367	true, it will be removed from the queue.
831		1368
		1369	These methods may invoke callbacks (and therefore the handle might be
		1370	destroyed after it returns).
		1371
832	=cut	1372	=cut
833		1373
834	our %RH;	1374	our %RH;
835		1375
836	sub register_read_type($$) {	1376	sub register_read_type($$) {
…		…
842	my $cb = pop;	1382	my $cb = pop;
843		1383
844	if (@_) {	1384	if (@_) {
845	my $type = shift;	1385	my $type = shift;
846		1386
		1387	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
847	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	1388	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
848	->($self, $cb, @_);	1389	->($self, $cb, @_);
849	}	1390	}
850		1391
851	push @{ $self->{_queue} }, $cb;	1392	push @{ $self->{_queue} }, $cb;
852	$self->_drain_rbuf unless $self->{_in_drain};	1393	$self->_drain_rbuf;
853	}	1394	}
854		1395
855	sub unshift_read {	1396	sub unshift_read {
856	my $self = shift;	1397	my $self = shift;
857	my $cb = pop;	1398	my $cb = pop;
858		1399
859	if (@_) {	1400	if (@_) {
860	my $type = shift;	1401	my $type = shift;
861		1402
		1403	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
862	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")	1404	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
863	->($self, $cb, @_);	1405	->($self, $cb, @_);
864	}	1406	}
865		1407
866
867	unshift @{ $self->{_queue} }, $cb;	1408	unshift @{ $self->{_queue} }, $cb;
868	$self->_drain_rbuf unless $self->{_in_drain};	1409	$self->_drain_rbuf;
869	}	1410	}
870		1411
871	=item $handle->push_read (type => @args, $cb)	1412	=item $handle->push_read (type => @args, $cb)
872		1413
873	=item $handle->unshift_read (type => @args, $cb)	1414	=item $handle->unshift_read (type => @args, $cb)
874		1415
875	Instead of providing a callback that parses the data itself you can chose	1416	Instead of providing a callback that parses the data itself you can chose
876	between a number of predefined parsing formats, for chunks of data, lines	1417	between a number of predefined parsing formats, for chunks of data, lines
877	etc.	1418	etc. You can also specify the (fully qualified) name of a package, in
		1419	which case AnyEvent tries to load the package and then expects to find the
		1420	C<anyevent_read_type> function inside (see "custom read types", below).
878		1421
879	Predefined types are (if you have ideas for additional types, feel free to	1422	Predefined types are (if you have ideas for additional types, feel free to
880	drop by and tell us):	1423	drop by and tell us):
881		1424
882	=over 4	1425	=over 4
…		…
974	the receive buffer when neither C<$accept> nor C<$reject> match,	1517	the receive buffer when neither C<$accept> nor C<$reject> match,
975	and everything preceding and including the match will be accepted	1518	and everything preceding and including the match will be accepted
976	unconditionally. This is useful to skip large amounts of data that you	1519	unconditionally. This is useful to skip large amounts of data that you
977	know cannot be matched, so that the C<$accept> or C<$reject> regex do not	1520	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
978	have to start matching from the beginning. This is purely an optimisation	1521	have to start matching from the beginning. This is purely an optimisation
979	and is usually worth only when you expect more than a few kilobytes.	1522	and is usually worth it only when you expect more than a few kilobytes.
980		1523
981	Example: expect a http header, which ends at C<\015\012\015\012>. Since we	1524	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
982	expect the header to be very large (it isn't in practise, but...), we use	1525	expect the header to be very large (it isn't in practice, but...), we use
983	a skip regex to skip initial portions. The skip regex is tricky in that	1526	a skip regex to skip initial portions. The skip regex is tricky in that
984	it only accepts something not ending in either \015 or \012, as these are	1527	it only accepts something not ending in either \015 or \012, as these are
985	required for the accept regex.	1528	required for the accept regex.
986		1529
987	$handle->push_read (regex =>	1530	$handle->push_read (regex =>
…		…
1006	return 1;	1549	return 1;
1007	}	1550	}
1008		1551
1009	# reject	1552	# reject
1010	if ($reject && $$rbuf =~ $reject) {	1553	if ($reject && $$rbuf =~ $reject) {
1011	$self->_error (&Errno::EBADMSG);	1554	$self->_error (Errno::EBADMSG);
1012	}	1555	}
1013		1556
1014	# skip	1557	# skip
1015	if ($skip && $$rbuf =~ $skip) {	1558	if ($skip && $$rbuf =~ $skip) {
1016	$data .= substr $$rbuf, 0, $+[0], "";	1559	$data .= substr $$rbuf, 0, $+[0], "";
…		…
1032	my ($self, $cb) = @_;	1575	my ($self, $cb) = @_;
1033		1576
1034	sub {	1577	sub {
1035	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {	1578	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
1036	if ($_[0]{rbuf} =~ /[^0-9]/) {	1579	if ($_[0]{rbuf} =~ /[^0-9]/) {
1037	$self->_error (&Errno::EBADMSG);	1580	$self->_error (Errno::EBADMSG);
1038	}	1581	}
1039	return;	1582	return;
1040	}	1583	}
1041		1584
1042	my $len = $1;	1585	my $len = $1;
…		…
1045	my $string = $_[1];	1588	my $string = $_[1];
1046	$_[0]->unshift_read (chunk => 1, sub {	1589	$_[0]->unshift_read (chunk => 1, sub {
1047	if ($_[1] eq ",") {	1590	if ($_[1] eq ",") {
1048	$cb->($_[0], $string);	1591	$cb->($_[0], $string);
1049	} else {	1592	} else {
1050	$self->_error (&Errno::EBADMSG);	1593	$self->_error (Errno::EBADMSG);
1051	}	1594	}
1052	});	1595	});
1053	});	1596	});
1054		1597
1055	1	1598	1
…		…
1061	An octet string prefixed with an encoded length. The encoding C<$format>	1604	An octet string prefixed with an encoded length. The encoding C<$format>
1062	uses the same format as a Perl C<pack> format, but must specify a single	1605	uses the same format as a Perl C<pack> format, but must specify a single
1063	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an	1606	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
1064	optional C<!>, C<< < >> or C<< > >> modifier).	1607	optional C<!>, C<< < >> or C<< > >> modifier).
1065		1608
1066	DNS over TCP uses a prefix of C<n>, EPP uses a prefix of C<N>.	1609	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1610	EPP uses a prefix of C<N> (4 octtes).
1067		1611
1068	Example: read a block of data prefixed by its length in BER-encoded	1612	Example: read a block of data prefixed by its length in BER-encoded
1069	format (very efficient).	1613	format (very efficient).
1070		1614
1071	$handle->push_read (packstring => "w", sub {	1615	$handle->push_read (packstring => "w", sub {
…		…
1101	}	1645	}
1102	};	1646	};
1103		1647
1104	=item json => $cb->($handle, $hash_or_arrayref)	1648	=item json => $cb->($handle, $hash_or_arrayref)
1105		1649
1106	Reads a JSON object or array, decodes it and passes it to the callback.	1650	Reads a JSON object or array, decodes it and passes it to the
		1651	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
1107		1652
1108	If a C<json> object was passed to the constructor, then that will be used	1653	If a C<json> object was passed to the constructor, then that will be used
1109	for the final decode, otherwise it will create a JSON coder expecting UTF-8.	1654	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
1110		1655
1111	This read type uses the incremental parser available with JSON version	1656	This read type uses the incremental parser available with JSON version
…		…
1120	=cut	1665	=cut
1121		1666
1122	register_read_type json => sub {	1667	register_read_type json => sub {
1123	my ($self, $cb) = @_;	1668	my ($self, $cb) = @_;
1124		1669
1125	require JSON;	1670	my $json = $self->{json} ||= json_coder;
1126		1671
1127	my $data;	1672	my $data;
1128	my $rbuf = \$self->{rbuf};	1673	my $rbuf = \$self->{rbuf};
1129		1674
1130	my $json = $self->{json} ||= JSON->new->utf8;
1131
1132	sub {	1675	sub {
1133	my $ref = $json->incr_parse ($self->{rbuf});	1676	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
1134		1677
1135	if ($ref) {	1678	if ($ref) {
1136	$self->{rbuf} = $json->incr_text;	1679	$self->{rbuf} = $json->incr_text;
1137	$json->incr_text = "";	1680	$json->incr_text = "";
1138	$cb->($self, $ref);	1681	$cb->($self, $ref);
1139		1682
1140	1	1683	1
		1684	} elsif ($@) {
		1685	# error case
		1686	$json->incr_skip;
		1687
		1688	$self->{rbuf} = $json->incr_text;
		1689	$json->incr_text = "";
		1690
		1691	$self->_error (Errno::EBADMSG);
		1692
		1693	()
1141	} else {	1694	} else {
1142	$self->{rbuf} = "";	1695	$self->{rbuf} = "";
		1696
1143	()	1697	()
1144	}	1698	}
1145	}	1699	}
1146	};	1700	};
1147		1701
…		…
1179	# read remaining chunk	1733	# read remaining chunk
1180	$_[0]->unshift_read (chunk => $len, sub {	1734	$_[0]->unshift_read (chunk => $len, sub {
1181	if (my $ref = eval { Storable::thaw ($_[1]) }) {	1735	if (my $ref = eval { Storable::thaw ($_[1]) }) {
1182	$cb->($_[0], $ref);	1736	$cb->($_[0], $ref);
1183	} else {	1737	} else {
1184	$self->_error (&Errno::EBADMSG);	1738	$self->_error (Errno::EBADMSG);
1185	}	1739	}
1186	});	1740	});
1187	}	1741	}
1188		1742
1189	1	1743	1
1190	}	1744	}
1191	};	1745	};
1192		1746
1193	=back	1747	=back
1194		1748
1195	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)	1749	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
1196		1750
1197	This function (not method) lets you add your own types to C<push_read>.	1751	Instead of one of the predefined types, you can also specify the name
		1752	of a package. AnyEvent will try to load the package and then expects to
		1753	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1754	progressively tries to load the parent package until it either finds the
		1755	function (good) or runs out of packages (bad).
1198		1756
1199	Whenever the given C<type> is used, C<push_read> will invoke the code	1757	Whenever this type is used, C<push_read> will invoke the function with the
1200	reference with the handle object, the callback and the remaining	1758	handle object, the original callback and the remaining arguments.
1201	arguments.
1202		1759
1203	The code reference is supposed to return a callback (usually a closure)	1760	The function is supposed to return a callback (usually a closure) that
1204	that works as a plain read callback (see C<< ->push_read ($cb) >>).	1761	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1762	mentally treat the function as a "configurable read type to read callback"
		1763	converter.
1205		1764
1206	It should invoke the passed callback when it is done reading (remember to	1765	It should invoke the original callback when it is done reading (remember
1207	pass C<$handle> as first argument as all other callbacks do that).	1766	to pass C<$handle> as first argument as all other callbacks do that,
		1767	although there is no strict requirement on this).
1208		1768
1209	Note that this is a function, and all types registered this way will be
1210	global, so try to use unique names.
1211
1212	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,	1769	For examples, see the source of this module (F<perldoc -m
1213	search for C<register_read_type>)).	1770	AnyEvent::Handle>, search for C<register_read_type>)).
1214		1771
1215	=item $handle->stop_read	1772	=item $handle->stop_read
1216		1773
1217	=item $handle->start_read	1774	=item $handle->start_read
1218		1775
…		…
1224	Note that AnyEvent::Handle will automatically C<start_read> for you when	1781	Note that AnyEvent::Handle will automatically C<start_read> for you when
1225	you change the C<on_read> callback or push/unshift a read callback, and it	1782	you change the C<on_read> callback or push/unshift a read callback, and it
1226	will automatically C<stop_read> for you when neither C<on_read> is set nor	1783	will automatically C<stop_read> for you when neither C<on_read> is set nor
1227	there are any read requests in the queue.	1784	there are any read requests in the queue.
1228		1785
		1786	In older versions of this module (<= 5.3), these methods had no effect,
		1787	as TLS does not support half-duplex connections. In current versions they
		1788	work as expected, as this behaviour is required to avoid certain resource
		1789	attacks, where the program would be forced to read (and buffer) arbitrary
		1790	amounts of data before being able to send some data. The drawback is that
		1791	some readings of the the SSL/TLS specifications basically require this
		1792	attack to be working, as SSL/TLS implementations might stall sending data
		1793	during a rehandshake.
		1794
		1795	As a guideline, during the initial handshake, you should not stop reading,
		1796	and as a client, it might cause problems, depending on your applciation.
		1797
1229	=cut	1798	=cut
1230		1799
1231	sub stop_read {	1800	sub stop_read {
1232	my ($self) = @_;	1801	my ($self) = @_;
1233		1802
…		…
1235	}	1804	}
1236		1805
1237	sub start_read {	1806	sub start_read {
1238	my ($self) = @_;	1807	my ($self) = @_;
1239		1808
1240	unless ($self->{_rw} || $self->{_eof}) {	1809	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
1241	Scalar::Util::weaken $self;	1810	Scalar::Util::weaken $self;
1242		1811
1243	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1812	$self->{_rw} = AE::io $self->{fh}, 0, sub {
1244	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1813	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1245	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1814	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
1246		1815
1247	if ($len > 0) {	1816	if ($len > 0) {
1248	$self->{_activity} = AnyEvent->now;	1817	$self->{_activity} = $self->{_ractivity} = AE::now;
1249		1818
1250	$self->{filter_r}	1819	if ($self->{tls}) {
1251	? $self->{filter_r}($self, $rbuf)	1820	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1252	: $self->{_in_drain} || $self->_drain_rbuf;	1821
		1822	&_dotls ($self);
		1823	} else {
		1824	$self->_drain_rbuf;
		1825	}
		1826
		1827	if ($len == $self->{read_size}) {
		1828	$self->{read_size} *= 2;
		1829	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		1830	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		1831	}
1253		1832
1254	} elsif (defined $len) {	1833	} elsif (defined $len) {
1255	delete $self->{_rw};	1834	delete $self->{_rw};
1256	$self->{_eof} = 1;	1835	$self->{_eof} = 1;
1257	$self->_drain_rbuf unless $self->{_in_drain};	1836	$self->_drain_rbuf;
1258		1837
1259	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {	1838	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
1260	return $self->_error ($!, 1);	1839	return $self->_error ($!, 1);
1261	}	1840	}
1262	});	1841	};
1263	}	1842	}
1264	}	1843	}
1265		1844
		1845	our $ERROR_SYSCALL;
		1846	our $ERROR_WANT_READ;
		1847
		1848	sub _tls_error {
		1849	my ($self, $err) = @_;
		1850
		1851	return $self->_error ($!, 1)
		1852	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1853
		1854	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1855
		1856	# reduce error string to look less scary
		1857	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1858
		1859	if ($self->{_on_starttls}) {
		1860	(delete $self->{_on_starttls})->($self, undef, $err);
		1861	&_freetls;
		1862	} else {
		1863	&_freetls;
		1864	$self->_error (Errno::EPROTO, 1, $err);
		1865	}
		1866	}
		1867
		1868	# poll the write BIO and send the data if applicable
		1869	# also decode read data if possible
		1870	# this is basiclaly our TLS state machine
		1871	# more efficient implementations are possible with openssl,
		1872	# but not with the buggy and incomplete Net::SSLeay.
1266	sub _dotls {	1873	sub _dotls {
1267	my ($self) = @_;	1874	my ($self) = @_;
1268		1875
1269	my $buf;	1876	my $tmp;
1270		1877
1271	if (length $self->{_tls_wbuf}) {	1878	if (length $self->{_tls_wbuf}) {
1272	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {	1879	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
1273	substr $self->{_tls_wbuf}, 0, $len, "";	1880	substr $self->{_tls_wbuf}, 0, $tmp, "";
1274	}	1881	}
1275	}
1276		1882
		1883	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1884	return $self->_tls_error ($tmp)
		1885	if $tmp != $ERROR_WANT_READ
		1886	&& ($tmp != $ERROR_SYSCALL || $!);
		1887	}
		1888
		1889	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1890	unless (length $tmp) {
		1891	$self->{_on_starttls}
		1892	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1893	&_freetls;
		1894
		1895	if ($self->{on_stoptls}) {
		1896	$self->{on_stoptls}($self);
		1897	return;
		1898	} else {
		1899	# let's treat SSL-eof as we treat normal EOF
		1900	delete $self->{_rw};
		1901	$self->{_eof} = 1;
		1902	}
		1903	}
		1904
		1905	$self->{_tls_rbuf} .= $tmp;
		1906	$self->_drain_rbuf;
		1907	$self->{tls} or return; # tls session might have gone away in callback
		1908	}
		1909
		1910	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1911	return $self->_tls_error ($tmp)
		1912	if $tmp != $ERROR_WANT_READ
		1913	&& ($tmp != $ERROR_SYSCALL || $!);
		1914
1277	if (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {	1915	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1278	$self->{wbuf} .= $buf;	1916	$self->{wbuf} .= $tmp;
1279	$self->_drain_wbuf;	1917	$self->_drain_wbuf;
		1918	$self->{tls} or return; # tls session might have gone away in callback
1280	}	1919	}
1281		1920
1282	while (defined ($buf = Net::SSLeay::read ($self->{tls}))) {	1921	$self->{_on_starttls}
1283	if (length $buf) {	1922	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
1284	$self->{rbuf} .= $buf;	1923	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
1285	$self->_drain_rbuf unless $self->{_in_drain};
1286	} else {
1287	# let's treat SSL-eof as we treat normal EOF
1288	$self->{_eof} = 1;
1289	$self->_shutdown;
1290	return;
1291	}
1292	}
1293
1294	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
1295
1296	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
1297	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
1298	return $self->_error ($!, 1);
1299	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
1300	return $self->_error (&Errno::EIO, 1);
1301	}
1302
1303	# all others are fine for our purposes
1304	}
1305	}	1924	}
1306		1925
1307	=item $handle->starttls ($tls[, $tls_ctx])	1926	=item $handle->starttls ($tls[, $tls_ctx])
1308		1927
1309	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1928	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
1310	object is created, you can also do that at a later time by calling	1929	object is created, you can also do that at a later time by calling
1311	C<starttls>.	1930	C<starttls>.
1312		1931
		1932	Starting TLS is currently an asynchronous operation - when you push some
		1933	write data and then call C<< ->starttls >> then TLS negotiation will start
		1934	immediately, after which the queued write data is then sent.
		1935
1313	The first argument is the same as the C<tls> constructor argument (either	1936	The first argument is the same as the C<tls> constructor argument (either
1314	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1937	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
1315		1938
1316	The second argument is the optional C<Net::SSLeay::CTX> object that is	1939	The second argument is the optional C<AnyEvent::TLS> object that is used
1317	used when AnyEvent::Handle has to create its own TLS connection object.	1940	when AnyEvent::Handle has to create its own TLS connection object, or
		1941	a hash reference with C<< key => value >> pairs that will be used to
		1942	construct a new context.
1318		1943
1319	The TLS connection object will end up in C<< $handle->{tls} >> after this	1944	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
1320	call and can be used or changed to your liking. Note that the handshake	1945	context in C<< $handle->{tls_ctx} >> after this call and can be used or
1321	might have already started when this function returns.	1946	changed to your liking. Note that the handshake might have already started
		1947	when this function returns.
1322		1948
		1949	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1950	handshakes on the same stream. It is best to not attempt to use the
		1951	stream after stopping TLS.
		1952
		1953	This method may invoke callbacks (and therefore the handle might be
		1954	destroyed after it returns).
		1955
1323	=cut	1956	=cut
		1957
		1958	our %TLS_CACHE; #TODO not yet documented, should we?
1324		1959
1325	sub starttls {	1960	sub starttls {
1326	my ($self, $ssl, $ctx) = @_;	1961	my ($self, $tls, $ctx) = @_;
1327		1962
1328	$self->stoptls;	1963	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1964	if $self->{tls};
1329		1965
1330	if ($ssl eq "accept") {	1966	$self->{tls} = $tls;
1331	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1967	$self->{tls_ctx} = $ctx if @_ > 2;
1332	Net::SSLeay::set_accept_state ($ssl);	1968
1333	} elsif ($ssl eq "connect") {	1969	return unless $self->{fh};
1334	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1970
1335	Net::SSLeay::set_connect_state ($ssl);	1971	require Net::SSLeay;
		1972
		1973	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1974	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1975
		1976	$tls = delete $self->{tls};
		1977	$ctx = $self->{tls_ctx};
		1978
		1979	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1980
		1981	if ("HASH" eq ref $ctx) {
		1982	require AnyEvent::TLS;
		1983
		1984	if ($ctx->{cache}) {
		1985	my $key = $ctx+0;
		1986	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1987	} else {
		1988	$ctx = new AnyEvent::TLS %$ctx;
		1989	}
		1990	}
1336	}	1991
1337		1992	$self->{tls_ctx} = $ctx || TLS_CTX ();
1338	$self->{tls} = $ssl;	1993	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
1339		1994
1340	# basically, this is deep magic (because SSL_read should have the same issues)	1995	# basically, this is deep magic (because SSL_read should have the same issues)
1341	# but the openssl maintainers basically said: "trust us, it just works".	1996	# but the openssl maintainers basically said: "trust us, it just works".
1342	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1997	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
1343	# and mismaintained ssleay-module doesn't even offer them).	1998	# and mismaintained ssleay-module doesn't even offer them).
1344	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1999	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		2000	#
		2001	# in short: this is a mess.
		2002	#
		2003	# note that we do not try to keep the length constant between writes as we are required to do.
		2004	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		2005	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		2006	# have identity issues in that area.
1345	Net::SSLeay::CTX_set_mode ($self->{tls},	2007	# Net::SSLeay::CTX_set_mode ($ssl,
1346	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	2008	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
1347	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	2009	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		2010	Net::SSLeay::CTX_set_mode ($tls, 1|2);
1348		2011
1349	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2012	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1350	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2013	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1351		2014
		2015	Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
		2016	$self->{rbuf} = "";
		2017
1352	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});	2018	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
1353		2019
1354	$self->{filter_w} = sub {	2020	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
1355	$_[0]{_tls_wbuf} .= ${$_[1]};	2021	if $self->{on_starttls};
1356	&_dotls;	2022
1357	};	2023	&_dotls; # need to trigger the initial handshake
1358	$self->{filter_r} = sub {	2024	$self->start_read; # make sure we actually do read
1359	Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
1360	&_dotls;
1361	};
1362	}	2025	}
1363		2026
1364	=item $handle->stoptls	2027	=item $handle->stoptls
1365		2028
1366	Destroys the SSL connection, if any. Partial read or write data will be	2029	Shuts down the SSL connection - this makes a proper EOF handshake by
1367	lost.	2030	sending a close notify to the other side, but since OpenSSL doesn't
		2031	support non-blocking shut downs, it is not guaranteed that you can re-use
		2032	the stream afterwards.
		2033
		2034	This method may invoke callbacks (and therefore the handle might be
		2035	destroyed after it returns).
1368		2036
1369	=cut	2037	=cut
1370		2038
1371	sub stoptls {	2039	sub stoptls {
1372	my ($self) = @_;	2040	my ($self) = @_;
1373		2041
1374	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	2042	if ($self->{tls} && $self->{fh}) {
		2043	Net::SSLeay::shutdown ($self->{tls});
1375		2044
1376	delete $self->{_rbio};	2045	&_dotls;
1377	delete $self->{_wbio};	2046
1378	delete $self->{_tls_wbuf};	2047	# # we don't give a shit. no, we do, but we can't. no...#d#
1379	delete $self->{filter_r};	2048	# # we, we... have to use openssl :/#d#
1380	delete $self->{filter_w};	2049	# &_freetls;#d#
		2050	}
1381	}	2051	}
		2052
		2053	sub _freetls {
		2054	my ($self) = @_;
		2055
		2056	return unless $self->{tls};
		2057
		2058	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2059	if $self->{tls} > 0;
		2060
		2061	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		2062	}
		2063
		2064	=item $handle->resettls
		2065
		2066	This rarely-used method simply resets and TLS state on the handle, usually
		2067	causing data loss.
		2068
		2069	One case where it may be useful is when you want to skip over the data in
		2070	the stream but you are not interested in interpreting it, so data loss is
		2071	no concern.
		2072
		2073	=cut
		2074
		2075	*resettls = \&_freetls;
1382		2076
1383	sub DESTROY {	2077	sub DESTROY {
1384	my $self = shift;	2078	my ($self) = @_;
1385		2079
1386	$self->stoptls;	2080	&_freetls;
1387		2081
1388	my $linger = exists $self->{linger} ? $self->{linger} : 3600;	2082	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
1389		2083
1390	if ($linger && length $self->{wbuf}) {	2084	if ($linger && length $self->{wbuf} && $self->{fh}) {
1391	my $fh = delete $self->{fh};	2085	my $fh = delete $self->{fh};
1392	my $wbuf = delete $self->{wbuf};	2086	my $wbuf = delete $self->{wbuf};
1393		2087
1394	my @linger;	2088	my @linger;
1395		2089
1396	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {	2090	push @linger, AE::io $fh, 1, sub {
1397	my $len = syswrite $fh, $wbuf, length $wbuf;	2091	my $len = syswrite $fh, $wbuf, length $wbuf;
1398		2092
1399	if ($len > 0) {	2093	if ($len > 0) {
1400	substr $wbuf, 0, $len, "";	2094	substr $wbuf, 0, $len, "";
1401	} else {	2095	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
1402	@linger = (); # end	2096	@linger = (); # end
1403	}	2097	}
		2098	};
		2099	push @linger, AE::timer $linger, 0, sub {
		2100	@linger = ();
		2101	};
		2102	}
		2103	}
		2104
		2105	=item $handle->destroy
		2106
		2107	Shuts down the handle object as much as possible - this call ensures that
		2108	no further callbacks will be invoked and as many resources as possible
		2109	will be freed. Any method you will call on the handle object after
		2110	destroying it in this way will be silently ignored (and it will return the
		2111	empty list).
		2112
		2113	Normally, you can just "forget" any references to an AnyEvent::Handle
		2114	object and it will simply shut down. This works in fatal error and EOF
		2115	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2116	callback, so when you want to destroy the AnyEvent::Handle object from
		2117	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2118	that case.
		2119
		2120	Destroying the handle object in this way has the advantage that callbacks
		2121	will be removed as well, so if those are the only reference holders (as
		2122	is common), then one doesn't need to do anything special to break any
		2123	reference cycles.
		2124
		2125	The handle might still linger in the background and write out remaining
		2126	data, as specified by the C<linger> option, however.
		2127
		2128	=cut
		2129
		2130	sub destroy {
		2131	my ($self) = @_;
		2132
		2133	$self->DESTROY;
		2134	%$self = ();
		2135	bless $self, "AnyEvent::Handle::destroyed";
		2136	}
		2137
		2138	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2139	#nop
		2140	}
		2141
		2142	=item $handle->destroyed
		2143
		2144	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2145	->destroy >>, true otherwise.
		2146
		2147	Can be useful to decide whether the handle is still valid after some
		2148	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2149	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2150	can destroy the handle, so work can be avoided by checking sometimes:
		2151
		2152	$hdl->starttls ("accept");
		2153	return if $hdl->destroyed;
		2154	$hdl->push_write (...
		2155
		2156	Note that the call to C<push_write> will silently be ignored if the handle
		2157	has been destroyed, so often you can just ignore the possibility of the
		2158	handle being destroyed.
		2159
		2160	=cut
		2161
		2162	sub destroyed { 0 }
		2163	sub AnyEvent::Handle::destroyed::destroyed { 1 }
		2164
		2165	=item AnyEvent::Handle::TLS_CTX
		2166
		2167	This function creates and returns the AnyEvent::TLS object used by default
		2168	for TLS mode.
		2169
		2170	The context is created by calling L<AnyEvent::TLS> without any arguments.
		2171
		2172	=cut
		2173
		2174	our $TLS_CTX;
		2175
		2176	sub TLS_CTX() {
		2177	$TLS_CTX ||= do {
		2178	require AnyEvent::TLS;
		2179
		2180	new AnyEvent::TLS
		2181	}
		2182	}
		2183
		2184	=back
		2185
		2186
		2187	=head1 NONFREQUENTLY ASKED QUESTIONS
		2188
		2189	=over 4
		2190
		2191	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2192	still get further invocations!
		2193
		2194	That's because AnyEvent::Handle keeps a reference to itself when handling
		2195	read or write callbacks.
		2196
		2197	It is only safe to "forget" the reference inside EOF or error callbacks,
		2198	from within all other callbacks, you need to explicitly call the C<<
		2199	->destroy >> method.
		2200
		2201	=item Why is my C<on_eof> callback never called?
		2202
		2203	Probably because your C<on_error> callback is being called instead: When
		2204	you have outstanding requests in your read queue, then an EOF is
		2205	considered an error as you clearly expected some data.
		2206
		2207	To avoid this, make sure you have an empty read queue whenever your handle
		2208	is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
		2209	an C<on_read> handler that simply pushes the first read requests in the
		2210	queue.
		2211
		2212	See also the next question, which explains this in a bit more detail.
		2213
		2214	=item How can I serve requests in a loop?
		2215
		2216	Most protocols consist of some setup phase (authentication for example)
		2217	followed by a request handling phase, where the server waits for requests
		2218	and handles them, in a loop.
		2219
		2220	There are two important variants: The first (traditional, better) variant
		2221	handles requests until the server gets some QUIT command, causing it to
		2222	close the connection first (highly desirable for a busy TCP server). A
		2223	client dropping the connection is an error, which means this variant can
		2224	detect an unexpected detection close.
		2225
		2226	To handle this case, always make sure you have a on-empty read queue, by
		2227	pushing the "read request start" handler on it:
		2228
		2229	# we assume a request starts with a single line
		2230	my @start_request; @start_request = (line => sub {
		2231	my ($hdl, $line) = @_;
		2232
		2233	... handle request
		2234
		2235	# push next request read, possibly from a nested callback
		2236	$hdl->push_read (@start_request);
		2237	});
		2238
		2239	# auth done, now go into request handling loop
		2240	# now push the first @start_request
		2241	$hdl->push_read (@start_request);
		2242
		2243	By always having an outstanding C<push_read>, the handle always expects
		2244	some data and raises the C<EPIPE> error when the connction is dropped
		2245	unexpectedly.
		2246
		2247	The second variant is a protocol where the client can drop the connection
		2248	at any time. For TCP, this means that the server machine may run out of
		2249	sockets easier, and in general, it means you cnanot distinguish a protocl
		2250	failure/client crash from a normal connection close. Nevertheless, these
		2251	kinds of protocols are common (and sometimes even the best solution to the
		2252	problem).
		2253
		2254	Having an outstanding read request at all times is possible if you ignore
		2255	C<EPIPE> errors, but this doesn't help with when the client drops the
		2256	connection during a request, which would still be an error.
		2257
		2258	A better solution is to push the initial request read in an C<on_read>
		2259	callback. This avoids an error, as when the server doesn't expect data
		2260	(i.e. is idly waiting for the next request, an EOF will not raise an
		2261	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2262	and simpler:
		2263
		2264	# auth done, now go into request handling loop
		2265	$hdl->on_read (sub {
		2266	my ($hdl) = @_;
		2267
		2268	# called each time we receive data but the read queue is empty
		2269	# simply start read the request
		2270
		2271	$hdl->push_read (line => sub {
		2272	my ($hdl, $line) = @_;
		2273
		2274	... handle request
		2275
		2276	# do nothing special when the request has been handled, just
		2277	# let the request queue go empty.
1404	});	2278	});
1405	push @linger, AnyEvent->timer (after => $linger, cb => sub {
1406	@linger = ();
1407	});	2279	});
		2280
		2281	=item I get different callback invocations in TLS mode/Why can't I pause
		2282	reading?
		2283
		2284	Unlike, say, TCP, TLS connections do not consist of two independent
		2285	communication channels, one for each direction. Or put differently, the
		2286	read and write directions are not independent of each other: you cannot
		2287	write data unless you are also prepared to read, and vice versa.
		2288
		2289	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2290	callback invocations when you are not expecting any read data - the reason
		2291	is that AnyEvent::Handle always reads in TLS mode.
		2292
		2293	During the connection, you have to make sure that you always have a
		2294	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2295	connection (or when you no longer want to use it) you can call the
		2296	C<destroy> method.
		2297
		2298	=item How do I read data until the other side closes the connection?
		2299
		2300	If you just want to read your data into a perl scalar, the easiest way
		2301	to achieve this is by setting an C<on_read> callback that does nothing,
		2302	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2303	will be in C<$_[0]{rbuf}>:
		2304
		2305	$handle->on_read (sub { });
		2306	$handle->on_eof (undef);
		2307	$handle->on_error (sub {
		2308	my $data = delete $_[0]{rbuf};
		2309	});
		2310
		2311	Note that this example removes the C<rbuf> member from the handle object,
		2312	which is not normally allowed by the API. It is expressly permitted in
		2313	this case only, as the handle object needs to be destroyed afterwards.
		2314
		2315	The reason to use C<on_error> is that TCP connections, due to latencies
		2316	and packets loss, might get closed quite violently with an error, when in
		2317	fact all data has been received.
		2318
		2319	It is usually better to use acknowledgements when transferring data,
		2320	to make sure the other side hasn't just died and you got the data
		2321	intact. This is also one reason why so many internet protocols have an
		2322	explicit QUIT command.
		2323
		2324	=item I don't want to destroy the handle too early - how do I wait until
		2325	all data has been written?
		2326
		2327	After writing your last bits of data, set the C<on_drain> callback
		2328	and destroy the handle in there - with the default setting of
		2329	C<low_water_mark> this will be called precisely when all data has been
		2330	written to the socket:
		2331
		2332	$handle->push_write (...);
		2333	$handle->on_drain (sub {
		2334	warn "all data submitted to the kernel\n";
		2335	undef $handle;
		2336	});
		2337
		2338	If you just want to queue some data and then signal EOF to the other side,
		2339	consider using C<< ->push_shutdown >> instead.
		2340
		2341	=item I want to contact a TLS/SSL server, I don't care about security.
		2342
		2343	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2344	connect to it and then create the AnyEvent::Handle with the C<tls>
		2345	parameter:
		2346
		2347	tcp_connect $host, $port, sub {
		2348	my ($fh) = @_;
		2349
		2350	my $handle = new AnyEvent::Handle
		2351	fh => $fh,
		2352	tls => "connect",
		2353	on_error => sub { ... };
		2354
		2355	$handle->push_write (...);
1408	}	2356	};
1409	}
1410		2357
1411	=item AnyEvent::Handle::TLS_CTX	2358	=item I want to contact a TLS/SSL server, I do care about security.
1412		2359
1413	This function creates and returns the Net::SSLeay::CTX object used by	2360	Then you should additionally enable certificate verification, including
1414	default for TLS mode.	2361	peername verification, if the protocol you use supports it (see
		2362	L<AnyEvent::TLS>, C<verify_peername>).
1415		2363
1416	The context is created like this:	2364	E.g. for HTTPS:
1417		2365
1418	Net::SSLeay::load_error_strings;	2366	tcp_connect $host, $port, sub {
1419	Net::SSLeay::SSLeay_add_ssl_algorithms;	2367	my ($fh) = @_;
1420	Net::SSLeay::randomize;
1421		2368
1422	my $CTX = Net::SSLeay::CTX_new;	2369	my $handle = new AnyEvent::Handle
		2370	fh => $fh,
		2371	peername => $host,
		2372	tls => "connect",
		2373	tls_ctx => { verify => 1, verify_peername => "https" },
		2374	...
1423		2375
1424	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL	2376	Note that you must specify the hostname you connected to (or whatever
		2377	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2378	peername verification will be done.
1425		2379
1426	=cut	2380	The above will use the system-dependent default set of trusted CA
		2381	certificates. If you want to check against a specific CA, add the
		2382	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
1427		2383
1428	our $TLS_CTX;	2384	tls_ctx => {
		2385	verify => 1,
		2386	verify_peername => "https",
		2387	ca_file => "my-ca-cert.pem",
		2388	},
1429		2389
1430	sub TLS_CTX() {	2390	=item I want to create a TLS/SSL server, how do I do that?
1431	$TLS_CTX || do {
1432	require Net::SSLeay;
1433		2391
1434	Net::SSLeay::load_error_strings ();	2392	Well, you first need to get a server certificate and key. You have
1435	Net::SSLeay::SSLeay_add_ssl_algorithms ();	2393	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
1436	Net::SSLeay::randomize ();	2394	self-signed certificate (cheap. check the search engine of your choice,
		2395	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2396	nice program for that purpose).
1437		2397
1438	$TLS_CTX = Net::SSLeay::CTX_new ();	2398	Then create a file with your private key (in PEM format, see
		2399	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2400	file should then look like this:
1439		2401
1440	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());	2402	-----BEGIN RSA PRIVATE KEY-----
		2403	...header data
		2404	... lots of base64'y-stuff
		2405	-----END RSA PRIVATE KEY-----
1441		2406
1442	$TLS_CTX	2407	-----BEGIN CERTIFICATE-----
1443	}	2408	... lots of base64'y-stuff
1444	}	2409	-----END CERTIFICATE-----
		2410
		2411	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2412	specify this file as C<cert_file>:
		2413
		2414	tcp_server undef, $port, sub {
		2415	my ($fh) = @_;
		2416
		2417	my $handle = new AnyEvent::Handle
		2418	fh => $fh,
		2419	tls => "accept",
		2420	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2421	...
		2422
		2423	When you have intermediate CA certificates that your clients might not
		2424	know about, just append them to the C<cert_file>.
1445		2425
1446	=back	2426	=back
		2427
1447		2428
1448	=head1 SUBCLASSING AnyEvent::Handle	2429	=head1 SUBCLASSING AnyEvent::Handle
1449		2430
1450	In many cases, you might want to subclass AnyEvent::Handle.	2431	In many cases, you might want to subclass AnyEvent::Handle.
1451		2432
…		…
1468		2449
1469	=item * all members not documented here and not prefixed with an underscore	2450	=item * all members not documented here and not prefixed with an underscore
1470	are free to use in subclasses.	2451	are free to use in subclasses.
1471		2452
1472	Of course, new versions of AnyEvent::Handle may introduce more "public"	2453	Of course, new versions of AnyEvent::Handle may introduce more "public"
1473	member variables, but thats just life, at least it is documented.	2454	member variables, but that's just life. At least it is documented.
1474		2455
1475	=back	2456	=back
1476		2457
1477	=head1 AUTHOR	2458	=head1 AUTHOR
1478		2459

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