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Revision 1.20 by elmex, Sat May 24 08:16:50 2008 UTC vs.
Revision 1.209 by root, Wed Dec 29 04:40:23 2010 UTC

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict;
5
6	use AnyEvent ();
7	use AnyEvent::Util ();
8	use Scalar::Util ();
9	use Carp ();
10	use Fcntl ();
11	use Errno qw/EAGAIN EINTR/;
12
13	=head1 NAME	1	=head1 NAME
14		2
15	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	3	AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
16
17	This module is experimental.
18
19	=cut
20
21	our $VERSION = '0.04';
22		4
23	=head1 SYNOPSIS	5	=head1 SYNOPSIS
24		6
25	use AnyEvent;	7	use AnyEvent;
26	use AnyEvent::Handle;	8	use AnyEvent::Handle;
27		9
28	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
29		11
30	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	12	my $hdl; $hdl = new AnyEvent::Handle
31
32	#TODO
33
34	# or use the constructor to pass the callback:
35
36	my $ae_fh2 =
37	AnyEvent::Handle->new (
38	fh => \*STDIN,	13	fh => \*STDIN,
39	on_eof => sub {	14	on_error => sub {
40	$cv->broadcast;	15	my ($hdl, $fatal, $msg) = @_;
41	},	16	warn "got error $msg\n";
42	#TODO	17	$hdl->destroy;
		18	$cv->send;
43	);	19	};
44		20
45	$cv->wait;	21	# send some request line
		22	$hdl->push_write ("getinfo\015\012");
		23
		24	# read the response line
		25	$hdl->push_read (line => sub {
		26	my ($hdl, $line) = @_;
		27	warn "got line <$line>\n";
		28	$cv->send;
		29	});
		30
		31	$cv->recv;
46		32
47	=head1 DESCRIPTION	33	=head1 DESCRIPTION
48		34
49	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
50	filehandles. For utility functions for doing non-blocking connects and accepts	36	stream-based filehandles (sockets, pipes, and other stream things).
51	on sockets see L<AnyEvent::Util>.
52		37
		38	The L<AnyEvent::Intro> tutorial contains some well-documented
		39	AnyEvent::Handle examples.
		40
53	In the following, when the documentation refers to of "bytes" then this	41	In the following, where the documentation refers to "bytes", it means
54	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
55	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.
56		47
57	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
58	argument.	49	argument.
59		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
60	=head1 METHODS	82	=head1 METHODS
61		83
62	=over 4	84	=over 4
63		85
64	=item B<new (%args)>	86	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
65		87
66	The constructor supports these arguments (all as key => value pairs).	88	The constructor supports these arguments (all as C<< key => value >> pairs).
67		89
68	=over 4	90	=over 4
69		91
70	=item fh => $filehandle [MANDATORY]	92	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
71		93
72	The filehandle this L<AnyEvent::Handle> object will operate on.	94	The filehandle this L<AnyEvent::Handle> object will operate on.
73
74	NOTE: The filehandle will be set to non-blocking (using	95	NOTE: The filehandle will be set to non-blocking mode (using
75	AnyEvent::Util::fh_nonblocking).	96	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		97	that mode.
76		98
77	=item on_eof => $cb->($self)	99	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
78		100
79	Set the callback to be called on EOF.	101	Try to connect to the specified host and service (port), using
		102	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		103	default C<peername>.
80		104
81	While not mandatory, it is highly recommended to set an eof callback,	105	You have to specify either this parameter, or C<fh>, above.
82	otherwise you might end up with a closed socket while you are still
83	waiting for data.
84		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
85	=item on_error => $cb->($self)	116	=item on_prepare => $cb->($handle)
86		117
		118	This (rarely used) callback is called before a new connection is
		119	attempted, but after the file handle has been created. It could be used to
		120	prepare the file handle with parameters required for the actual connect
		121	(as opposed to settings that can be changed when the connection is already
		122	established).
		123
		124	The return value of this callback should be the connect timeout value in
		125	seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
		126	default timeout is to be used).
		127
		128	=item on_connect => $cb->($handle, $host, $port, $retry->())
		129
		130	This callback is called when a connection has been successfully established.
		131
		132	The peer's numeric host and port (the socket peername) are passed as
		133	parameters, together with a retry callback.
		134
		135	If, for some reason, the handle is not acceptable, calling C<$retry>
		136	will continue with the next connection target (in case of multi-homed
		137	hosts or SRV records there can be multiple connection endpoints). At the
		138	time it is called the read and write queues, eof status, tls status and
		139	similar properties of the handle will have been reset.
		140
		141	In most cases, you should ignore the C<$retry> parameter.
		142
		143	=item on_connect_error => $cb->($handle, $message)
		144
		145	This callback is called when the connection could not be
		146	established. C<$!> will contain the relevant error code, and C<$message> a
		147	message describing it (usually the same as C<"$!">).
		148
		149	If this callback isn't specified, then C<on_error> will be called with a
		150	fatal error instead.
		151
		152	=back
		153
		154	=item on_error => $cb->($handle, $fatal, $message)
		155
87	This is the fatal error callback, that is called when, well, a fatal error	156	This is the error callback, which is called when, well, some error
88	occurs, such as not being able to resolve the hostname, failure to connect	157	occured, such as not being able to resolve the hostname, failure to
89	or a read error.	158	connect, or a read error.
90		159
91	The object will not be in a usable state when this callback has been	160	Some errors are fatal (which is indicated by C<$fatal> being true). On
92	called.	161	fatal errors the handle object will be destroyed (by a call to C<< ->
		162	destroy >>) after invoking the error callback (which means you are free to
		163	examine the handle object). Examples of fatal errors are an EOF condition
		164	with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
		165	cases where the other side can close the connection at will, it is
		166	often easiest to not report C<EPIPE> errors in this callback.
93		167
		168	AnyEvent::Handle tries to find an appropriate error code for you to check
		169	against, but in some cases (TLS errors), this does not work well. It is
		170	recommended to always output the C<$message> argument in human-readable
		171	error messages (it's usually the same as C<"$!">).
		172
		173	Non-fatal errors can be retried by returning, but it is recommended
		174	to simply ignore this parameter and instead abondon the handle object
		175	when this callback is invoked. Examples of non-fatal errors are timeouts
		176	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		177
94	On callback entrance, the value of C<$!> contains the operating system	178	On entry to the callback, the value of C<$!> contains the operating
95	error (or C<ENOSPC> or C<EPIPE>).	179	system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		180	C<EPROTO>).
96		181
97	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
98	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
99	die.	184	C<croak>.
100		185
101	=item on_read => $cb->($self)	186	=item on_read => $cb->($handle)
102		187
103	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
104	and no read request is in the queue.	189	and no read request is in the queue (unlike read queue callbacks, this
		190	callback will only be called when at least one octet of data is in the
		191	read buffer).
105		192
106	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 >>
107	method or access the C<$self->{rbuf}> member directly.	194	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		195	must not enlarge or modify the read buffer, you can only remove data at
		196	the beginning from it.
108		197
		198	You can also call C<< ->push_read (...) >> or any other function that
		199	modifies the read queue. Or do both. Or ...
		200
109	When an EOF condition is detected then AnyEvent::Handle will first try to	201	When an EOF condition is detected, AnyEvent::Handle will first try to
110	feed all the remaining data to the queued callbacks and C<on_read> before	202	feed all the remaining data to the queued callbacks and C<on_read> before
111	calling the C<on_eof> callback. If no progress can be made, then a fatal	203	calling the C<on_eof> callback. If no progress can be made, then a fatal
112	error will be raised (with C<$!> set to C<EPIPE>).	204	error will be raised (with C<$!> set to C<EPIPE>).
113		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
114	=item on_drain => $cb->()	227	=item on_drain => $cb->($handle)
115		228
116	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
117	(or when the callback is set and the buffer is empty already).	230	(or immediately if the buffer is empty already).
118		231
119	To append to the write buffer, use the C<< ->push_write >> method.	232	To append to the write buffer, use the C<< ->push_write >> method.
		233
		234	This callback is useful when you don't want to put all of your write data
		235	into the queue at once, for example, when you want to write the contents
		236	of some file to the socket you might not want to read the whole file into
		237	memory and push it into the queue, but instead only read more data from
		238	the file when the write queue becomes empty.
		239
		240	=item timeout => $fractional_seconds
		241
		242	=item rtimeout => $fractional_seconds
		243
		244	=item wtimeout => $fractional_seconds
		245
		246	If non-zero, then these enables an "inactivity" timeout: whenever this
		247	many seconds pass without a successful read or write on the underlying
		248	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
		249	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		250	error will be raised).
		251
		252	There are three variants of the timeouts that work independently
		253	of each other, for both read and write, just read, and just write:
		254	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		255	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		256	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		257
		258	Note that timeout processing is active even when you do not have
		259	any outstanding read or write requests: If you plan to keep the connection
		260	idle then you should disable the timeout temporarily or ignore the timeout
		261	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		262	restart the timeout.
		263
		264	Zero (the default) disables this timeout.
		265
		266	=item on_timeout => $cb->($handle)
		267
		268	Called whenever the inactivity timeout passes. If you return from this
		269	callback, then the timeout will be reset as if some activity had happened,
		270	so this condition is not fatal in any way.
120		271
121	=item rbuf_max => <bytes>	272	=item rbuf_max => <bytes>
122		273
123	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	274	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
124	when the read buffer ever (strictly) exceeds this size. This is useful to	275	when the read buffer ever (strictly) exceeds this size. This is useful to
125	avoid denial-of-service attacks.	276	avoid some forms of denial-of-service attacks.
126		277
127	For example, a server accepting connections from untrusted sources should	278	For example, a server accepting connections from untrusted sources should
128	be configured to accept only so-and-so much data that it cannot act on	279	be configured to accept only so-and-so much data that it cannot act on
129	(for example, when expecting a line, an attacker could send an unlimited	280	(for example, when expecting a line, an attacker could send an unlimited
130	amount of data without a callback ever being called as long as the line	281	amount of data without a callback ever being called as long as the line
131	isn't finished).	282	isn't finished).
132		283
		284	=item wbuf_max => <bytes>
		285
		286	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		287	when the write buffer ever (strictly) exceeds this size. This is useful to
		288	avoid some forms of denial-of-service attacks.
		289
		290	Although the units of this parameter is bytes, this is the I<raw> number
		291	of bytes not yet accepted by the kernel. This can make a difference when
		292	you e.g. use TLS, as TLS typically makes your write data larger (but it
		293	can also make it smaller due to compression).
		294
		295	As an example of when this limit is useful, take a chat server that sends
		296	chat messages to a client. If the client does not read those in a timely
		297	manner then the send buffer in the server would grow unbounded.
		298
		299	=item autocork => <boolean>
		300
		301	When disabled (the default), C<push_write> will try to immediately
		302	write the data to the handle if possible. This avoids having to register
		303	a write watcher and wait for the next event loop iteration, but can
		304	be inefficient if you write multiple small chunks (on the wire, this
		305	disadvantage is usually avoided by your kernel's nagle algorithm, see
		306	C<no_delay>, but this option can save costly syscalls).
		307
		308	When enabled, writes will always be queued till the next event loop
		309	iteration. This is efficient when you do many small writes per iteration,
		310	but less efficient when you do a single write only per iteration (or when
		311	the write buffer often is full). It also increases write latency.
		312
		313	=item no_delay => <boolean>
		314
		315	When doing small writes on sockets, your operating system kernel might
		316	wait a bit for more data before actually sending it out. This is called
		317	the Nagle algorithm, and usually it is beneficial.
		318
		319	In some situations you want as low a delay as possible, which can be
		320	accomplishd by setting this option to a true value.
		321
		322	The default is your operating system's default behaviour (most likely
		323	enabled). This option explicitly enables or disables it, if possible.
		324
		325	=item keepalive => <boolean>
		326
		327	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		328	normally, TCP connections have no time-out once established, so TCP
		329	connections, once established, can stay alive forever even when the other
		330	side has long gone. TCP keepalives are a cheap way to take down long-lived
		331	TCP connections when the other side becomes unreachable. While the default
		332	is OS-dependent, TCP keepalives usually kick in after around two hours,
		333	and, if the other side doesn't reply, take down the TCP connection some 10
		334	to 15 minutes later.
		335
		336	It is harmless to specify this option for file handles that do not support
		337	keepalives, and enabling it on connections that are potentially long-lived
		338	is usually a good idea.
		339
		340	=item oobinline => <boolean>
		341
		342	BSD majorly fucked up the implementation of TCP urgent data. The result
		343	is that almost no OS implements TCP according to the specs, and every OS
		344	implements it slightly differently.
		345
		346	If you want to handle TCP urgent data, then setting this flag (the default
		347	is enabled) gives you the most portable way of getting urgent data, by
		348	putting it into the stream.
		349
		350	Since BSD emulation of OOB data on top of TCP's urgent data can have
		351	security implications, AnyEvent::Handle sets this flag automatically
		352	unless explicitly specified. Note that setting this flag after
		353	establishing a connection I<may> be a bit too late (data loss could
		354	already have occured on BSD systems), but at least it will protect you
		355	from most attacks.
		356
133	=item read_size => <bytes>	357	=item read_size => <bytes>
134		358
135	The default read block size (the amount of bytes this module will try to read	359	The initial read block size, the number of bytes this module will try to
136	on each [loop iteration). Default: C<4096>.	360	read during each loop iteration. Each handle object will consume at least
		361	this amount of memory for the read buffer as well, so when handling many
		362	connections requirements). See also C<max_read_size>. Default: C<2048>.
		363
		364	=item max_read_size => <bytes>
		365
		366	The maximum read buffer size used by the dynamic adjustment
		367	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		368	one go it will double C<read_size> up to the maximum given by this
		369	option. Default: C<131072> or C<read_size>, whichever is higher.
137		370
138	=item low_water_mark => <bytes>	371	=item low_water_mark => <bytes>
139		372
140	Sets the amount of bytes (default: C<0>) that make up an "empty" write	373	Sets the number of bytes (default: C<0>) that make up an "empty" write
141	buffer: If the write reaches this size or gets even samller it is	374	buffer: If the buffer reaches this size or gets even samller it is
142	considered empty.	375	considered empty.
143		376
		377	Sometimes it can be beneficial (for performance reasons) to add data to
		378	the write buffer before it is fully drained, but this is a rare case, as
		379	the operating system kernel usually buffers data as well, so the default
		380	is good in almost all cases.
		381
		382	=item linger => <seconds>
		383
		384	If this is non-zero (default: C<3600>), the destructor of the
		385	AnyEvent::Handle object will check whether there is still outstanding
		386	write data and will install a watcher that will write this data to the
		387	socket. No errors will be reported (this mostly matches how the operating
		388	system treats outstanding data at socket close time).
		389
		390	This will not work for partial TLS data that could not be encoded
		391	yet. This data will be lost. Calling the C<stoptls> method in time might
		392	help.
		393
		394	=item peername => $string
		395
		396	A string used to identify the remote site - usually the DNS hostname
		397	(I<not> IDN!) used to create the connection, rarely the IP address.
		398
		399	Apart from being useful in error messages, this string is also used in TLS
		400	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		401	verification will be skipped when C<peername> is not specified or is
		402	C<undef>.
		403
144	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	404	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
145		405
146	When this parameter is given, it enables TLS (SSL) mode, that means it	406	When this parameter is given, it enables TLS (SSL) mode, that means
147	will start making tls handshake and will transparently encrypt/decrypt	407	AnyEvent will start a TLS handshake as soon as the connection has been
148	data.	408	established and will transparently encrypt/decrypt data afterwards.
149		409
150	For the TLS server side, use C<accept>, and for the TLS client side of a	410	All TLS protocol errors will be signalled as C<EPROTO>, with an
151	connection, use C<connect> mode.	411	appropriate error message.
		412
		413	TLS mode requires Net::SSLeay to be installed (it will be loaded
		414	automatically when you try to create a TLS handle): this module doesn't
		415	have a dependency on that module, so if your module requires it, you have
		416	to add the dependency yourself.
		417
		418	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		419	C<accept>, and for the TLS client side of a connection, use C<connect>
		420	mode.
152		421
153	You can also provide your own TLS connection object, but you have	422	You can also provide your own TLS connection object, but you have
154	to make sure that you call either C<Net::SSLeay::set_connect_state>	423	to make sure that you call either C<Net::SSLeay::set_connect_state>
155	or C<Net::SSLeay::set_accept_state> on it before you pass it to	424	or C<Net::SSLeay::set_accept_state> on it before you pass it to
156	AnyEvent::Handle.	425	AnyEvent::Handle. Also, this module will take ownership of this connection
		426	object.
157		427
158	=item tls_ctx => $ssl_ctx	428	At some future point, AnyEvent::Handle might switch to another TLS
		429	implementation, then the option to use your own session object will go
		430	away.
159		431
		432	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		433	passing in the wrong integer will lead to certain crash. This most often
		434	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		435	segmentation fault.
		436
		437	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
		438
		439	=item tls_ctx => $anyevent_tls
		440
160	Use the given Net::SSLeay::CTX object to create the new TLS connection	441	Use the given C<AnyEvent::TLS> object to create the new TLS connection
161	(unless a connection object was specified directly). If this parameter is	442	(unless a connection object was specified directly). If this
162	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	443	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		444	C<AnyEvent::Handle::TLS_CTX>.
		445
		446	Instead of an object, you can also specify a hash reference with C<< key
		447	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		448	new TLS context object.
		449
		450	=item on_starttls => $cb->($handle, $success[, $error_message])
		451
		452	This callback will be invoked when the TLS/SSL handshake has finished. If
		453	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		454	(C<on_stoptls> will not be called in this case).
		455
		456	The session in C<< $handle->{tls} >> can still be examined in this
		457	callback, even when the handshake was not successful.
		458
		459	TLS handshake failures will not cause C<on_error> to be invoked when this
		460	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		461
		462	Without this callback, handshake failures lead to C<on_error> being
		463	called as usual.
		464
		465	Note that you cannot just call C<starttls> again in this callback. If you
		466	need to do that, start an zero-second timer instead whose callback can
		467	then call C<< ->starttls >> again.
		468
		469	=item on_stoptls => $cb->($handle)
		470
		471	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		472	set, then it will be invoked after freeing the TLS session. If it is not,
		473	then a TLS shutdown condition will be treated like a normal EOF condition
		474	on the handle.
		475
		476	The session in C<< $handle->{tls} >> can still be examined in this
		477	callback.
		478
		479	This callback will only be called on TLS shutdowns, not when the
		480	underlying handle signals EOF.
		481
		482	=item json => JSON or JSON::XS object
		483
		484	This is the json coder object used by the C<json> read and write types.
		485
		486	If you don't supply it, then AnyEvent::Handle will create and use a
		487	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		488	texts.
		489
		490	Note that you are responsible to depend on the JSON module if you want to
		491	use this functionality, as AnyEvent does not have a dependency itself.
163		492
164	=back	493	=back
165		494
166	=cut	495	=cut
167		496
168	sub new {	497	sub new {
169	my $class = shift;	498	my $class = shift;
170
171	my $self = bless { @_ }, $class;	499	my $self = bless { @_ }, $class;
172		500
173	$self->{fh} or Carp::croak "mandatory argument fh is missing";	501	if ($self->{fh}) {
		502	$self->_start;
		503	return unless $self->{fh}; # could be gone by now
		504
		505	} elsif ($self->{connect}) {
		506	require AnyEvent::Socket;
		507
		508	$self->{peername} = $self->{connect}[0]
		509	unless exists $self->{peername};
		510
		511	$self->{_skip_drain_rbuf} = 1;
		512
		513	{
		514	Scalar::Util::weaken (my $self = $self);
		515
		516	$self->{_connect} =
		517	AnyEvent::Socket::tcp_connect (
		518	$self->{connect}[0],
		519	$self->{connect}[1],
		520	sub {
		521	my ($fh, $host, $port, $retry) = @_;
		522
		523	delete $self->{_connect}; # no longer needed
		524
		525	if ($fh) {
		526	$self->{fh} = $fh;
		527
		528	delete $self->{_skip_drain_rbuf};
		529	$self->_start;
		530
		531	$self->{on_connect}
		532	and $self->{on_connect}($self, $host, $port, sub {
		533	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		534	$self->{_skip_drain_rbuf} = 1;
		535	&$retry;
		536	});
		537
		538	} else {
		539	if ($self->{on_connect_error}) {
		540	$self->{on_connect_error}($self, "$!");
		541	$self->destroy;
		542	} else {
		543	$self->_error ($!, 1);
		544	}
		545	}
		546	},
		547	sub {
		548	local $self->{fh} = $_[0];
		549
		550	$self->{on_prepare}
		551	? $self->{on_prepare}->($self)
		552	: ()
		553	}
		554	);
		555	}
		556
		557	} else {
		558	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		559	}
		560
		561	$self
		562	}
		563
		564	sub _start {
		565	my ($self) = @_;
		566
		567	# too many clueless people try to use udp and similar sockets
		568	# with AnyEvent::Handle, do them a favour.
		569	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		570	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		571	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
174		572
175	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	573	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
176		574
177	if ($self->{tls}) {	575	$self->{_activity} =
178	require Net::SSLeay;	576	$self->{_ractivity} =
		577	$self->{_wactivity} = AE::now;
		578
		579	$self->{read_size} ||= 2048;
		580	$self->{max_read_size} = $self->{read_size}
		581	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		582
		583	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		584	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		585	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		586
		587	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		588	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		589
		590	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		591
179	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	592	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
180	}	593	if $self->{tls};
181		594
182	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
183	$self->on_error (delete $self->{on_error}) if $self->{on_error};
184	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	595	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
185	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
186		596
187	$self->start_read;	597	$self->start_read
		598	if $self->{on_read} || @{ $self->{_queue} };
188		599
189	$self	600	$self->_drain_wbuf;
190	}	601	}
191		602
192	sub _shutdown {
193	my ($self) = @_;
194
195	delete $self->{rw};
196	delete $self->{ww};
197	delete $self->{fh};
198	}
199
200	sub error {	603	sub _error {
201	my ($self) = @_;	604	my ($self, $errno, $fatal, $message) = @_;
202		605
203	{	606	$! = $errno;
204	local $!;	607	$message ||= "$!";
205	$self->_shutdown;
206	}
207		608
208	if ($self->{on_error}) {	609	if ($self->{on_error}) {
209	$self->{on_error}($self);	610	$self->{on_error}($self, $fatal, $message);
210	} else {	611	$self->destroy if $fatal;
		612	} elsif ($self->{fh} || $self->{connect}) {
		613	$self->destroy;
211	die "AnyEvent::Handle uncaught fatal error: $!";	614	Carp::croak "AnyEvent::Handle uncaught error: $message";
212	}	615	}
213	}	616	}
214		617
215	=item $fh = $handle->fh	618	=item $fh = $handle->fh
216		619
217	This method returns the filehandle of the L<AnyEvent::Handle> object.	620	This method returns the file handle used to create the L<AnyEvent::Handle> object.
218		621
219	=cut	622	=cut
220		623
221	sub fh { $_[0]->{fh} }	624	sub fh { $_[0]{fh} }
222		625
223	=item $handle->on_error ($cb)	626	=item $handle->on_error ($cb)
224		627
225	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	628	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
226		629
…		…
238		641
239	sub on_eof {	642	sub on_eof {
240	$_[0]{on_eof} = $_[1];	643	$_[0]{on_eof} = $_[1];
241	}	644	}
242		645
		646	=item $handle->on_timeout ($cb)
		647
		648	=item $handle->on_rtimeout ($cb)
		649
		650	=item $handle->on_wtimeout ($cb)
		651
		652	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		653	callback, or disables the callback (but not the timeout) if C<$cb> =
		654	C<undef>. See the C<timeout> constructor argument and method.
		655
		656	=cut
		657
		658	# see below
		659
		660	=item $handle->autocork ($boolean)
		661
		662	Enables or disables the current autocork behaviour (see C<autocork>
		663	constructor argument). Changes will only take effect on the next write.
		664
		665	=cut
		666
		667	sub autocork {
		668	$_[0]{autocork} = $_[1];
		669	}
		670
		671	=item $handle->no_delay ($boolean)
		672
		673	Enables or disables the C<no_delay> setting (see constructor argument of
		674	the same name for details).
		675
		676	=cut
		677
		678	sub no_delay {
		679	$_[0]{no_delay} = $_[1];
		680
		681	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		682	if $_[0]{fh};
		683	}
		684
		685	=item $handle->keepalive ($boolean)
		686
		687	Enables or disables the C<keepalive> setting (see constructor argument of
		688	the same name for details).
		689
		690	=cut
		691
		692	sub keepalive {
		693	$_[0]{keepalive} = $_[1];
		694
		695	eval {
		696	local $SIG{__DIE__};
		697	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		698	if $_[0]{fh};
		699	};
		700	}
		701
		702	=item $handle->oobinline ($boolean)
		703
		704	Enables or disables the C<oobinline> setting (see constructor argument of
		705	the same name for details).
		706
		707	=cut
		708
		709	sub oobinline {
		710	$_[0]{oobinline} = $_[1];
		711
		712	eval {
		713	local $SIG{__DIE__};
		714	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		715	if $_[0]{fh};
		716	};
		717	}
		718
		719	=item $handle->keepalive ($boolean)
		720
		721	Enables or disables the C<keepalive> setting (see constructor argument of
		722	the same name for details).
		723
		724	=cut
		725
		726	sub keepalive {
		727	$_[0]{keepalive} = $_[1];
		728
		729	eval {
		730	local $SIG{__DIE__};
		731	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		732	if $_[0]{fh};
		733	};
		734	}
		735
		736	=item $handle->on_starttls ($cb)
		737
		738	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		739
		740	=cut
		741
		742	sub on_starttls {
		743	$_[0]{on_starttls} = $_[1];
		744	}
		745
		746	=item $handle->on_stoptls ($cb)
		747
		748	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		749
		750	=cut
		751
		752	sub on_stoptls {
		753	$_[0]{on_stoptls} = $_[1];
		754	}
		755
		756	=item $handle->rbuf_max ($max_octets)
		757
		758	Configures the C<rbuf_max> setting (C<undef> disables it).
		759
		760	=item $handle->wbuf_max ($max_octets)
		761
		762	Configures the C<wbuf_max> setting (C<undef> disables it).
		763
		764	=cut
		765
		766	sub rbuf_max {
		767	$_[0]{rbuf_max} = $_[1];
		768	}
		769
		770	sub rbuf_max {
		771	$_[0]{wbuf_max} = $_[1];
		772	}
		773
		774	#############################################################################
		775
		776	=item $handle->timeout ($seconds)
		777
		778	=item $handle->rtimeout ($seconds)
		779
		780	=item $handle->wtimeout ($seconds)
		781
		782	Configures (or disables) the inactivity timeout.
		783
		784	=item $handle->timeout_reset
		785
		786	=item $handle->rtimeout_reset
		787
		788	=item $handle->wtimeout_reset
		789
		790	Reset the activity timeout, as if data was received or sent.
		791
		792	These methods are cheap to call.
		793
		794	=cut
		795
		796	for my $dir ("", "r", "w") {
		797	my $timeout = "${dir}timeout";
		798	my $tw = "_${dir}tw";
		799	my $on_timeout = "on_${dir}timeout";
		800	my $activity = "_${dir}activity";
		801	my $cb;
		802
		803	*$on_timeout = sub {
		804	$_[0]{$on_timeout} = $_[1];
		805	};
		806
		807	*$timeout = sub {
		808	my ($self, $new_value) = @_;
		809
		810	$new_value >= 0
		811	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		812
		813	$self->{$timeout} = $new_value;
		814	delete $self->{$tw}; &$cb;
		815	};
		816
		817	*{"${dir}timeout_reset"} = sub {
		818	$_[0]{$activity} = AE::now;
		819	};
		820
		821	# main workhorse:
		822	# reset the timeout watcher, as neccessary
		823	# also check for time-outs
		824	$cb = sub {
		825	my ($self) = @_;
		826
		827	if ($self->{$timeout} && $self->{fh}) {
		828	my $NOW = AE::now;
		829
		830	# when would the timeout trigger?
		831	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		832
		833	# now or in the past already?
		834	if ($after <= 0) {
		835	$self->{$activity} = $NOW;
		836
		837	if ($self->{$on_timeout}) {
		838	$self->{$on_timeout}($self);
		839	} else {
		840	$self->_error (Errno::ETIMEDOUT);
		841	}
		842
		843	# callback could have changed timeout value, optimise
		844	return unless $self->{$timeout};
		845
		846	# calculate new after
		847	$after = $self->{$timeout};
		848	}
		849
		850	Scalar::Util::weaken $self;
		851	return unless $self; # ->error could have destroyed $self
		852
		853	$self->{$tw} ||= AE::timer $after, 0, sub {
		854	delete $self->{$tw};
		855	$cb->($self);
		856	};
		857	} else {
		858	delete $self->{$tw};
		859	}
		860	}
		861	}
		862
243	#############################################################################	863	#############################################################################
244		864
245	=back	865	=back
246		866
247	=head2 WRITE QUEUE	867	=head2 WRITE QUEUE
…		…
260	=item $handle->on_drain ($cb)	880	=item $handle->on_drain ($cb)
261		881
262	Sets the C<on_drain> callback or clears it (see the description of	882	Sets the C<on_drain> callback or clears it (see the description of
263	C<on_drain> in the constructor).	883	C<on_drain> in the constructor).
264		884
		885	This method may invoke callbacks (and therefore the handle might be
		886	destroyed after it returns).
		887
265	=cut	888	=cut
266		889
267	sub on_drain {	890	sub on_drain {
268	my ($self, $cb) = @_;	891	my ($self, $cb) = @_;
269		892
270	$self->{on_drain} = $cb;	893	$self->{on_drain} = $cb;
271		894
272	$cb->($self)	895	$cb->($self)
273	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	896	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
274	}	897	}
275		898
276	=item $handle->push_write ($data)	899	=item $handle->push_write ($data)
277		900
278	Queues the given scalar to be written. You can push as much data as you	901	Queues the given scalar to be written. You can push as much data as
279	want (only limited by the available memory), as C<AnyEvent::Handle>	902	you want (only limited by the available memory and C<wbuf_max>), as
280	buffers it independently of the kernel.	903	C<AnyEvent::Handle> buffers it independently of the kernel.
		904
		905	This method may invoke callbacks (and therefore the handle might be
		906	destroyed after it returns).
281		907
282	=cut	908	=cut
283		909
284	sub _drain_wbuf {	910	sub _drain_wbuf {
285	my ($self) = @_;	911	my ($self) = @_;
286		912
287	unless ($self->{ww}) {	913	if (!$self->{_ww} && length $self->{wbuf}) {
		914
288	Scalar::Util::weaken $self;	915	Scalar::Util::weaken $self;
		916
289	my $cb = sub {	917	my $cb = sub {
290	my $len = syswrite $self->{fh}, $self->{wbuf};	918	my $len = syswrite $self->{fh}, $self->{wbuf};
291		919
292	if ($len > 0) {	920	if (defined $len) {
293	substr $self->{wbuf}, 0, $len, "";	921	substr $self->{wbuf}, 0, $len, "";
294		922
		923	$self->{_activity} = $self->{_wactivity} = AE::now;
		924
295	$self->{on_drain}($self)	925	$self->{on_drain}($self)
296	if $self->{low_water_mark} >= length $self->{wbuf}	926	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
297	&& $self->{on_drain};	927	&& $self->{on_drain};
298		928
299	delete $self->{ww} unless length $self->{wbuf};	929	delete $self->{_ww} unless length $self->{wbuf};
300	} elsif ($! != EAGAIN && $! != EINTR) {	930	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
301	$self->error;	931	$self->_error ($!, 1);
302	}	932	}
303	};	933	};
304		934
305	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	935	# try to write data immediately
		936	$cb->() unless $self->{autocork};
306		937
307	$cb->($self);	938	# if still data left in wbuf, we need to poll
		939	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		940	if length $self->{wbuf};
		941
		942	if (
		943	defined $self->{wbuf_max}
		944	&& $self->{wbuf_max} < length $self->{wbuf}
		945	) {
		946	$self->_error (Errno::ENOSPC, 1), return;
		947	}
308	};	948	};
		949	}
		950
		951	our %WH;
		952
		953	# deprecated
		954	sub register_write_type($$) {
		955	$WH{$_[0]} = $_[1];
309	}	956	}
310		957
311	sub push_write {	958	sub push_write {
312	my $self = shift;	959	my $self = shift;
313		960
		961	if (@_ > 1) {
		962	my $type = shift;
		963
		964	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
		965	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
		966	->($self, @_);
		967	}
		968
		969	# we downgrade here to avoid hard-to-track-down bugs,
		970	# and diagnose the problem earlier and better.
		971
314	if ($self->{filter_w}) {	972	if ($self->{tls}) {
315	$self->{filter_w}->($self, \$_[0]);	973	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		974	&_dotls ($self) if $self->{fh};
316	} else {	975	} else {
317	$self->{wbuf} .= $_[0];	976	utf8::downgrade $self->{wbuf} .= $_[0];
318	$self->_drain_wbuf;	977	$self->_drain_wbuf if $self->{fh};
319	}	978	}
320	}	979	}
		980
		981	=item $handle->push_write (type => @args)
		982
		983	Instead of formatting your data yourself, you can also let this module
		984	do the job by specifying a type and type-specific arguments. You
		985	can also specify the (fully qualified) name of a package, in which
		986	case AnyEvent tries to load the package and then expects to find the
		987	C<anyevent_write_type> function inside (see "custom write types", below).
		988
		989	Predefined types are (if you have ideas for additional types, feel free to
		990	drop by and tell us):
		991
		992	=over 4
		993
		994	=item netstring => $string
		995
		996	Formats the given value as netstring
		997	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		998
		999	=cut
		1000
		1001	register_write_type netstring => sub {
		1002	my ($self, $string) = @_;
		1003
		1004	(length $string) . ":$string,"
		1005	};
		1006
		1007	=item packstring => $format, $data
		1008
		1009	An octet string prefixed with an encoded length. The encoding C<$format>
		1010	uses the same format as a Perl C<pack> format, but must specify a single
		1011	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1012	optional C<!>, C<< < >> or C<< > >> modifier).
		1013
		1014	=cut
		1015
		1016	register_write_type packstring => sub {
		1017	my ($self, $format, $string) = @_;
		1018
		1019	pack "$format/a*", $string
		1020	};
		1021
		1022	=item json => $array_or_hashref
		1023
		1024	Encodes the given hash or array reference into a JSON object. Unless you
		1025	provide your own JSON object, this means it will be encoded to JSON text
		1026	in UTF-8.
		1027
		1028	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		1029	one end of a handle and read them at the other end without using any
		1030	additional framing.
		1031
		1032	The generated JSON text is guaranteed not to contain any newlines: While
		1033	this module doesn't need delimiters after or between JSON texts to be
		1034	able to read them, many other languages depend on that.
		1035
		1036	A simple RPC protocol that interoperates easily with others is to send
		1037	JSON arrays (or objects, although arrays are usually the better choice as
		1038	they mimic how function argument passing works) and a newline after each
		1039	JSON text:
		1040
		1041	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		1042	$handle->push_write ("\012");
		1043
		1044	An AnyEvent::Handle receiver would simply use the C<json> read type and
		1045	rely on the fact that the newline will be skipped as leading whitespace:
		1046
		1047	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1048
		1049	Other languages could read single lines terminated by a newline and pass
		1050	this line into their JSON decoder of choice.
		1051
		1052	=cut
		1053
		1054	sub json_coder() {
		1055	eval { require JSON::XS; JSON::XS->new->utf8 }
		1056	|| do { require JSON; JSON->new->utf8 }
		1057	}
		1058
		1059	register_write_type json => sub {
		1060	my ($self, $ref) = @_;
		1061
		1062	my $json = $self->{json} ||= json_coder;
		1063
		1064	$json->encode ($ref)
		1065	};
		1066
		1067	=item storable => $reference
		1068
		1069	Freezes the given reference using L<Storable> and writes it to the
		1070	handle. Uses the C<nfreeze> format.
		1071
		1072	=cut
		1073
		1074	register_write_type storable => sub {
		1075	my ($self, $ref) = @_;
		1076
		1077	require Storable;
		1078
		1079	pack "w/a*", Storable::nfreeze ($ref)
		1080	};
		1081
		1082	=back
		1083
		1084	=item $handle->push_shutdown
		1085
		1086	Sometimes you know you want to close the socket after writing your data
		1087	before it was actually written. One way to do that is to replace your
		1088	C<on_drain> handler by a callback that shuts down the socket (and set
		1089	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1090	replaces the C<on_drain> callback with:
		1091
		1092	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		1093
		1094	This simply shuts down the write side and signals an EOF condition to the
		1095	the peer.
		1096
		1097	You can rely on the normal read queue and C<on_eof> handling
		1098	afterwards. This is the cleanest way to close a connection.
		1099
		1100	This method may invoke callbacks (and therefore the handle might be
		1101	destroyed after it returns).
		1102
		1103	=cut
		1104
		1105	sub push_shutdown {
		1106	my ($self) = @_;
		1107
		1108	delete $self->{low_water_mark};
		1109	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1110	}
		1111
		1112	=item custom write types - Package::anyevent_write_type $handle, @args
		1113
		1114	Instead of one of the predefined types, you can also specify the name of
		1115	a package. AnyEvent will try to load the package and then expects to find
		1116	a function named C<anyevent_write_type> inside. If it isn't found, it
		1117	progressively tries to load the parent package until it either finds the
		1118	function (good) or runs out of packages (bad).
		1119
		1120	Whenever the given C<type> is used, C<push_write> will the function with
		1121	the handle object and the remaining arguments.
		1122
		1123	The function is supposed to return a single octet string that will be
		1124	appended to the write buffer, so you cna mentally treat this function as a
		1125	"arguments to on-the-wire-format" converter.
		1126
		1127	Example: implement a custom write type C<join> that joins the remaining
		1128	arguments using the first one.
		1129
		1130	$handle->push_write (My::Type => " ", 1,2,3);
		1131
		1132	# uses the following package, which can be defined in the "My::Type" or in
		1133	# the "My" modules to be auto-loaded, or just about anywhere when the
		1134	# My::Type::anyevent_write_type is defined before invoking it.
		1135
		1136	package My::Type;
		1137
		1138	sub anyevent_write_type {
		1139	my ($handle, $delim, @args) = @_;
		1140
		1141	join $delim, @args
		1142	}
		1143
		1144	=cut
321		1145
322	#############################################################################	1146	#############################################################################
323		1147
324	=back	1148	=back
325		1149
…		…
332	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1156	ways, the "simple" way, using only C<on_read> and the "complex" way, using
333	a queue.	1157	a queue.
334		1158
335	In the simple case, you just install an C<on_read> callback and whenever	1159	In the simple case, you just install an C<on_read> callback and whenever
336	new data arrives, it will be called. You can then remove some data (if	1160	new data arrives, it will be called. You can then remove some data (if
337	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1161	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
338	or not.	1162	leave the data there if you want to accumulate more (e.g. when only a
		1163	partial message has been received so far), or change the read queue with
		1164	e.g. C<push_read>.
339		1165
340	In the more complex case, you want to queue multiple callbacks. In this	1166	In the more complex case, you want to queue multiple callbacks. In this
341	case, AnyEvent::Handle will call the first queued callback each time new	1167	case, AnyEvent::Handle will call the first queued callback each time new
342	data arrives and removes it when it has done its job (see C<push_read>,	1168	data arrives (also the first time it is queued) and remove it when it has
343	below).	1169	done its job (see C<push_read>, below).
344		1170
345	This way you can, for example, push three line-reads, followed by reading	1171	This way you can, for example, push three line-reads, followed by reading
346	a chunk of data, and AnyEvent::Handle will execute them in order.	1172	a chunk of data, and AnyEvent::Handle will execute them in order.
347		1173
348	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1174	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
349	the specified number of bytes which give an XML datagram.	1175	the specified number of bytes which give an XML datagram.
350		1176
351	# in the default state, expect some header bytes	1177	# in the default state, expect some header bytes
352	$handle->on_read (sub {	1178	$handle->on_read (sub {
353	# some data is here, now queue the length-header-read (4 octets)	1179	# some data is here, now queue the length-header-read (4 octets)
354	shift->unshift_read_chunk (4, sub {	1180	shift->unshift_read (chunk => 4, sub {
355	# header arrived, decode	1181	# header arrived, decode
356	my $len = unpack "N", $_[1];	1182	my $len = unpack "N", $_[1];
357		1183
358	# now read the payload	1184	# now read the payload
359	shift->unshift_read_chunk ($len, sub {	1185	shift->unshift_read (chunk => $len, sub {
360	my $xml = $_[1];	1186	my $xml = $_[1];
361	# handle xml	1187	# handle xml
362	});	1188	});
363	});	1189	});
364	});	1190	});
365		1191
366	Example 2: Implement a client for a protocol that replies either with	1192	Example 2: Implement a client for a protocol that replies either with "OK"
367	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1193	and another line or "ERROR" for the first request that is sent, and 64
368	second request. Due tot he availability of a full queue, we can just	1194	bytes for the second request. Due to the availability of a queue, we can
369	pipeline sending both requests and manipulate the queue as necessary in	1195	just pipeline sending both requests and manipulate the queue as necessary
370	the callbacks:	1196	in the callbacks.
371		1197
372	# request one	1198	When the first callback is called and sees an "OK" response, it will
		1199	C<unshift> another line-read. This line-read will be queued I<before> the
		1200	64-byte chunk callback.
		1201
		1202	# request one, returns either "OK + extra line" or "ERROR"
373	$handle->push_write ("request 1\015\012");	1203	$handle->push_write ("request 1\015\012");
374		1204
375	# we expect "ERROR" or "OK" as response, so push a line read	1205	# we expect "ERROR" or "OK" as response, so push a line read
376	$handle->push_read_line (sub {	1206	$handle->push_read (line => sub {
377	# if we got an "OK", we have to _prepend_ another line,	1207	# if we got an "OK", we have to _prepend_ another line,
378	# so it will be read before the second request reads its 64 bytes	1208	# so it will be read before the second request reads its 64 bytes
379	# which are already in the queue when this callback is called	1209	# which are already in the queue when this callback is called
380	# we don't do this in case we got an error	1210	# we don't do this in case we got an error
381	if ($_[1] eq "OK") {	1211	if ($_[1] eq "OK") {
382	$_[0]->unshift_read_line (sub {	1212	$_[0]->unshift_read (line => sub {
383	my $response = $_[1];	1213	my $response = $_[1];
384	...	1214	...
385	});	1215	});
386	}	1216	}
387	});	1217	});
388		1218
389	# request two	1219	# request two, simply returns 64 octets
390	$handle->push_write ("request 2\015\012");	1220	$handle->push_write ("request 2\015\012");
391		1221
392	# simply read 64 bytes, always	1222	# simply read 64 bytes, always
393	$handle->push_read_chunk (64, sub {	1223	$handle->push_read (chunk => 64, sub {
394	my $response = $_[1];	1224	my $response = $_[1];
395	...	1225	...
396	});	1226	});
397		1227
398	=over 4	1228	=over 4
399		1229
400	=cut	1230	=cut
401		1231
402	sub _drain_rbuf {	1232	sub _drain_rbuf {
403	my ($self) = @_;	1233	my ($self) = @_;
		1234
		1235	# avoid recursion
		1236	return if $self->{_skip_drain_rbuf};
		1237	local $self->{_skip_drain_rbuf} = 1;
		1238
		1239	while () {
		1240	# we need to use a separate tls read buffer, as we must not receive data while
		1241	# we are draining the buffer, and this can only happen with TLS.
		1242	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1243	if exists $self->{_tls_rbuf};
		1244
		1245	my $len = length $self->{rbuf};
		1246
		1247	if (my $cb = shift @{ $self->{_queue} }) {
		1248	unless ($cb->($self)) {
		1249	# no progress can be made
		1250	# (not enough data and no data forthcoming)
		1251	$self->_error (Errno::EPIPE, 1), return
		1252	if $self->{_eof};
		1253
		1254	unshift @{ $self->{_queue} }, $cb;
		1255	last;
		1256	}
		1257	} elsif ($self->{on_read}) {
		1258	last unless $len;
		1259
		1260	$self->{on_read}($self);
		1261
		1262	if (
		1263	$len == length $self->{rbuf} # if no data has been consumed
		1264	&& !@{ $self->{_queue} } # and the queue is still empty
		1265	&& $self->{on_read} # but we still have on_read
		1266	) {
		1267	# no further data will arrive
		1268	# so no progress can be made
		1269	$self->_error (Errno::EPIPE, 1), return
		1270	if $self->{_eof};
		1271
		1272	last; # more data might arrive
		1273	}
		1274	} else {
		1275	# read side becomes idle
		1276	delete $self->{_rw} unless $self->{tls};
		1277	last;
		1278	}
		1279	}
		1280
		1281	if ($self->{_eof}) {
		1282	$self->{on_eof}
		1283	? $self->{on_eof}($self)
		1284	: $self->_error (0, 1, "Unexpected end-of-file");
		1285
		1286	return;
		1287	}
404		1288
405	if (	1289	if (
406	defined $self->{rbuf_max}	1290	defined $self->{rbuf_max}
407	&& $self->{rbuf_max} < length $self->{rbuf}	1291	&& $self->{rbuf_max} < length $self->{rbuf}
408	) {	1292	) {
409	$! = &Errno::ENOSPC; return $self->error;	1293	$self->_error (Errno::ENOSPC, 1), return;
410	}	1294	}
411		1295
412	return if $self->{in_drain};	1296	# may need to restart read watcher
413	local $self->{in_drain} = 1;	1297	unless ($self->{_rw}) {
414		1298	$self->start_read
415	while (my $len = length $self->{rbuf}) {	1299	if $self->{on_read} || @{ $self->{_queue} };
416	no strict 'refs';
417	if (my $cb = shift @{ $self->{queue} }) {
418	if (!$cb->($self)) {
419	if ($self->{eof}) {
420	# no progress can be made (not enough data and no data forthcoming)
421	$! = &Errno::EPIPE; return $self->error;
422	}
423
424	unshift @{ $self->{queue} }, $cb;
425	return;
426	}
427	} elsif ($self->{on_read}) {
428	$self->{on_read}($self);
429
430	if (
431	$self->{eof} # if no further data will arrive
432	&& $len == length $self->{rbuf} # and no data has been consumed
433	&& !@{ $self->{queue} } # and the queue is still empty
434	&& $self->{on_read} # and we still want to read data
435	) {
436	# then no progress can be made
437	$! = &Errno::EPIPE; return $self->error;
438	}
439	} else {
440	# read side becomes idle
441	delete $self->{rw};
442	return;
443	}
444	}
445
446	if ($self->{eof}) {
447	$self->_shutdown;
448	$self->{on_eof}($self)
449	if $self->{on_eof};
450	}	1300	}
451	}	1301	}
452		1302
453	=item $handle->on_read ($cb)	1303	=item $handle->on_read ($cb)
454		1304
455	This replaces the currently set C<on_read> callback, or clears it (when	1305	This replaces the currently set C<on_read> callback, or clears it (when
456	the new callback is C<undef>). See the description of C<on_read> in the	1306	the new callback is C<undef>). See the description of C<on_read> in the
457	constructor.	1307	constructor.
458		1308
		1309	This method may invoke callbacks (and therefore the handle might be
		1310	destroyed after it returns).
		1311
459	=cut	1312	=cut
460		1313
461	sub on_read {	1314	sub on_read {
462	my ($self, $cb) = @_;	1315	my ($self, $cb) = @_;
463		1316
464	$self->{on_read} = $cb;	1317	$self->{on_read} = $cb;
		1318	$self->_drain_rbuf if $cb;
465	}	1319	}
466		1320
467	=item $handle->rbuf	1321	=item $handle->rbuf
468		1322
469	Returns the read buffer (as a modifiable lvalue).	1323	Returns the read buffer (as a modifiable lvalue). You can also access the
		1324	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1325	much faster, and no less clean).
470		1326
471	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1327	The only operation allowed on the read buffer (apart from looking at it)
472	you want.	1328	is removing data from its beginning. Otherwise modifying or appending to
		1329	it is not allowed and will lead to hard-to-track-down bugs.
473		1330
474	NOTE: The read buffer should only be used or modified if the C<on_read>,	1331	NOTE: The read buffer should only be used or modified in the C<on_read>
475	C<push_read> or C<unshift_read> methods are used. The other read methods	1332	callback or when C<push_read> or C<unshift_read> are used with a single
476	automatically manage the read buffer.	1333	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1334	will manage the read buffer on their own.
477		1335
478	=cut	1336	=cut
479		1337
480	sub rbuf : lvalue {	1338	sub rbuf : lvalue {
481	$_[0]{rbuf}	1339	$_[0]{rbuf}
…		…
498		1356
499	If enough data was available, then the callback must remove all data it is	1357	If enough data was available, then the callback must remove all data it is
500	interested in (which can be none at all) and return a true value. After returning	1358	interested in (which can be none at all) and return a true value. After returning
501	true, it will be removed from the queue.	1359	true, it will be removed from the queue.
502		1360
		1361	These methods may invoke callbacks (and therefore the handle might be
		1362	destroyed after it returns).
		1363
503	=cut	1364	=cut
		1365
		1366	our %RH;
		1367
		1368	sub register_read_type($$) {
		1369	$RH{$_[0]} = $_[1];
		1370	}
504		1371
505	sub push_read {	1372	sub push_read {
506	my ($self, $cb) = @_;	1373	my $self = shift;
		1374	my $cb = pop;
507		1375
		1376	if (@_) {
		1377	my $type = shift;
		1378
		1379	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1380	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
		1381	->($self, $cb, @_);
		1382	}
		1383
508	push @{ $self->{queue} }, $cb;	1384	push @{ $self->{_queue} }, $cb;
509	$self->_drain_rbuf;	1385	$self->_drain_rbuf;
510	}	1386	}
511		1387
512	sub unshift_read {	1388	sub unshift_read {
513	my ($self, $cb) = @_;	1389	my $self = shift;
		1390	my $cb = pop;
514		1391
		1392	if (@_) {
		1393	my $type = shift;
		1394
		1395	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1396	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
		1397	->($self, $cb, @_);
		1398	}
		1399
515	push @{ $self->{queue} }, $cb;	1400	unshift @{ $self->{_queue} }, $cb;
516	$self->_drain_rbuf;	1401	$self->_drain_rbuf;
517	}	1402	}
518		1403
519	=item $handle->push_read_chunk ($len, $cb->($self, $data))	1404	=item $handle->push_read (type => @args, $cb)
520		1405
521	=item $handle->unshift_read_chunk ($len, $cb->($self, $data))	1406	=item $handle->unshift_read (type => @args, $cb)
522		1407
523	Append the given callback to the end of the queue (C<push_read_chunk>) or	1408	Instead of providing a callback that parses the data itself you can chose
524	prepend it (C<unshift_read_chunk>).	1409	between a number of predefined parsing formats, for chunks of data, lines
		1410	etc. You can also specify the (fully qualified) name of a package, in
		1411	which case AnyEvent tries to load the package and then expects to find the
		1412	C<anyevent_read_type> function inside (see "custom read types", below).
525		1413
526	The callback will be called only once C<$len> bytes have been read, and	1414	Predefined types are (if you have ideas for additional types, feel free to
527	these C<$len> bytes will be passed to the callback.	1415	drop by and tell us):
528		1416
529	=cut	1417	=over 4
530		1418
531	sub _read_chunk($$) {	1419	=item chunk => $octets, $cb->($handle, $data)
		1420
		1421	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1422	data read to the callback. The callback will never be called with less
		1423	data.
		1424
		1425	Example: read 2 bytes.
		1426
		1427	$handle->push_read (chunk => 2, sub {
		1428	warn "yay ", unpack "H*", $_[1];
		1429	});
		1430
		1431	=cut
		1432
		1433	register_read_type chunk => sub {
532	my ($self, $len, $cb) = @_;	1434	my ($self, $cb, $len) = @_;
533		1435
534	sub {	1436	sub {
535	$len <= length $_[0]{rbuf} or return;	1437	$len <= length $_[0]{rbuf} or return;
536	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1438	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
537	1	1439	1
538	}	1440	}
539	}	1441	};
540		1442
541	sub push_read_chunk {	1443	=item line => [$eol, ]$cb->($handle, $line, $eol)
542	$_[0]->push_read (&_read_chunk);
543	}
544
545
546	sub unshift_read_chunk {
547	$_[0]->unshift_read (&_read_chunk);
548	}
549
550	=item $handle->push_read_line ([$eol, ]$cb->($self, $line, $eol))
551
552	=item $handle->unshift_read_line ([$eol, ]$cb->($self, $line, $eol))
553
554	Append the given callback to the end of the queue (C<push_read_line>) or
555	prepend it (C<unshift_read_line>).
556		1444
557	The callback will be called only once a full line (including the end of	1445	The callback will be called only once a full line (including the end of
558	line marker, C<$eol>) has been read. This line (excluding the end of line	1446	line marker, C<$eol>) has been read. This line (excluding the end of line
559	marker) will be passed to the callback as second argument (C<$line>), and	1447	marker) will be passed to the callback as second argument (C<$line>), and
560	the end of line marker as the third argument (C<$eol>).	1448	the end of line marker as the third argument (C<$eol>).
…		…
571	Partial lines at the end of the stream will never be returned, as they are	1459	Partial lines at the end of the stream will never be returned, as they are
572	not marked by the end of line marker.	1460	not marked by the end of line marker.
573		1461
574	=cut	1462	=cut
575		1463
576	sub _read_line($$) {	1464	register_read_type line => sub {
577	my $self = shift;	1465	my ($self, $cb, $eol) = @_;
578	my $cb = pop;
579	my $eol = @_ ? shift : qr|(\015?\012)|;
580	my $pos;
581		1466
		1467	if (@_ < 3) {
		1468	# this is more than twice as fast as the generic code below
		1469	sub {
		1470	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1471
		1472	$cb->($_[0], $1, $2);
		1473	1
		1474	}
		1475	} else {
582	$eol = quotemeta $eol unless ref $eol;	1476	$eol = quotemeta $eol unless ref $eol;
583	$eol = qr|^(.*?)($eol)|s;	1477	$eol = qr|^(.*?)($eol)|s;
		1478
		1479	sub {
		1480	$_[0]{rbuf} =~ s/$eol// or return;
		1481
		1482	$cb->($_[0], $1, $2);
		1483	1
		1484	}
		1485	}
		1486	};
		1487
		1488	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1489
		1490	Makes a regex match against the regex object C<$accept> and returns
		1491	everything up to and including the match.
		1492
		1493	Example: read a single line terminated by '\n'.
		1494
		1495	$handle->push_read (regex => qr<\n>, sub { ... });
		1496
		1497	If C<$reject> is given and not undef, then it determines when the data is
		1498	to be rejected: it is matched against the data when the C<$accept> regex
		1499	does not match and generates an C<EBADMSG> error when it matches. This is
		1500	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1501	receive buffer overflow).
		1502
		1503	Example: expect a single decimal number followed by whitespace, reject
		1504	anything else (not the use of an anchor).
		1505
		1506	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1507
		1508	If C<$skip> is given and not C<undef>, then it will be matched against
		1509	the receive buffer when neither C<$accept> nor C<$reject> match,
		1510	and everything preceding and including the match will be accepted
		1511	unconditionally. This is useful to skip large amounts of data that you
		1512	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1513	have to start matching from the beginning. This is purely an optimisation
		1514	and is usually worth it only when you expect more than a few kilobytes.
		1515
		1516	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1517	expect the header to be very large (it isn't in practice, but...), we use
		1518	a skip regex to skip initial portions. The skip regex is tricky in that
		1519	it only accepts something not ending in either \015 or \012, as these are
		1520	required for the accept regex.
		1521
		1522	$handle->push_read (regex =>
		1523	qr<\015\012\015\012>,
		1524	undef, # no reject
		1525	qr<^.*[^\015\012]>,
		1526	sub { ... });
		1527
		1528	=cut
		1529
		1530	register_read_type regex => sub {
		1531	my ($self, $cb, $accept, $reject, $skip) = @_;
		1532
		1533	my $data;
		1534	my $rbuf = \$self->{rbuf};
584		1535
585	sub {	1536	sub {
586	$_[0]{rbuf} =~ s/$eol// or return;	1537	# accept
		1538	if ($$rbuf =~ $accept) {
		1539	$data .= substr $$rbuf, 0, $+[0], "";
		1540	$cb->($self, $data);
		1541	return 1;
		1542	}
		1543
		1544	# reject
		1545	if ($reject && $$rbuf =~ $reject) {
		1546	$self->_error (Errno::EBADMSG);
		1547	}
587		1548
588	$cb->($_[0], $1, $2);	1549	# skip
		1550	if ($skip && $$rbuf =~ $skip) {
		1551	$data .= substr $$rbuf, 0, $+[0], "";
		1552	}
		1553
		1554	()
		1555	}
		1556	};
		1557
		1558	=item netstring => $cb->($handle, $string)
		1559
		1560	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1561
		1562	Throws an error with C<$!> set to EBADMSG on format violations.
		1563
		1564	=cut
		1565
		1566	register_read_type netstring => sub {
		1567	my ($self, $cb) = @_;
		1568
		1569	sub {
		1570	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1571	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1572	$self->_error (Errno::EBADMSG);
		1573	}
		1574	return;
		1575	}
		1576
		1577	my $len = $1;
		1578
		1579	$self->unshift_read (chunk => $len, sub {
		1580	my $string = $_[1];
		1581	$_[0]->unshift_read (chunk => 1, sub {
		1582	if ($_[1] eq ",") {
		1583	$cb->($_[0], $string);
		1584	} else {
		1585	$self->_error (Errno::EBADMSG);
		1586	}
		1587	});
		1588	});
		1589
589	1	1590	1
590	}	1591	}
591	}	1592	};
592		1593
593	sub push_read_line {	1594	=item packstring => $format, $cb->($handle, $string)
594	$_[0]->push_read (&_read_line);
595	}
596		1595
597	sub unshift_read_line {	1596	An octet string prefixed with an encoded length. The encoding C<$format>
598	$_[0]->unshift_read (&_read_line);	1597	uses the same format as a Perl C<pack> format, but must specify a single
599	}	1598	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1599	optional C<!>, C<< < >> or C<< > >> modifier).
		1600
		1601	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1602	EPP uses a prefix of C<N> (4 octtes).
		1603
		1604	Example: read a block of data prefixed by its length in BER-encoded
		1605	format (very efficient).
		1606
		1607	$handle->push_read (packstring => "w", sub {
		1608	my ($handle, $data) = @_;
		1609	});
		1610
		1611	=cut
		1612
		1613	register_read_type packstring => sub {
		1614	my ($self, $cb, $format) = @_;
		1615
		1616	sub {
		1617	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1618	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1619	or return;
		1620
		1621	$format = length pack $format, $len;
		1622
		1623	# bypass unshift if we already have the remaining chunk
		1624	if ($format + $len <= length $_[0]{rbuf}) {
		1625	my $data = substr $_[0]{rbuf}, $format, $len;
		1626	substr $_[0]{rbuf}, 0, $format + $len, "";
		1627	$cb->($_[0], $data);
		1628	} else {
		1629	# remove prefix
		1630	substr $_[0]{rbuf}, 0, $format, "";
		1631
		1632	# read remaining chunk
		1633	$_[0]->unshift_read (chunk => $len, $cb);
		1634	}
		1635
		1636	1
		1637	}
		1638	};
		1639
		1640	=item json => $cb->($handle, $hash_or_arrayref)
		1641
		1642	Reads a JSON object or array, decodes it and passes it to the
		1643	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1644
		1645	If a C<json> object was passed to the constructor, then that will be used
		1646	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1647
		1648	This read type uses the incremental parser available with JSON version
		1649	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1650	dependency on your own: this module will load the JSON module, but
		1651	AnyEvent does not depend on it itself.
		1652
		1653	Since JSON texts are fully self-delimiting, the C<json> read and write
		1654	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1655	the C<json> write type description, above, for an actual example.
		1656
		1657	=cut
		1658
		1659	register_read_type json => sub {
		1660	my ($self, $cb) = @_;
		1661
		1662	my $json = $self->{json} ||= json_coder;
		1663
		1664	my $data;
		1665	my $rbuf = \$self->{rbuf};
		1666
		1667	sub {
		1668	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1669
		1670	if ($ref) {
		1671	$self->{rbuf} = $json->incr_text;
		1672	$json->incr_text = "";
		1673	$cb->($self, $ref);
		1674
		1675	1
		1676	} elsif ($@) {
		1677	# error case
		1678	$json->incr_skip;
		1679
		1680	$self->{rbuf} = $json->incr_text;
		1681	$json->incr_text = "";
		1682
		1683	$self->_error (Errno::EBADMSG);
		1684
		1685	()
		1686	} else {
		1687	$self->{rbuf} = "";
		1688
		1689	()
		1690	}
		1691	}
		1692	};
		1693
		1694	=item storable => $cb->($handle, $ref)
		1695
		1696	Deserialises a L<Storable> frozen representation as written by the
		1697	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1698	data).
		1699
		1700	Raises C<EBADMSG> error if the data could not be decoded.
		1701
		1702	=cut
		1703
		1704	register_read_type storable => sub {
		1705	my ($self, $cb) = @_;
		1706
		1707	require Storable;
		1708
		1709	sub {
		1710	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1711	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1712	or return;
		1713
		1714	my $format = length pack "w", $len;
		1715
		1716	# bypass unshift if we already have the remaining chunk
		1717	if ($format + $len <= length $_[0]{rbuf}) {
		1718	my $data = substr $_[0]{rbuf}, $format, $len;
		1719	substr $_[0]{rbuf}, 0, $format + $len, "";
		1720	$cb->($_[0], Storable::thaw ($data));
		1721	} else {
		1722	# remove prefix
		1723	substr $_[0]{rbuf}, 0, $format, "";
		1724
		1725	# read remaining chunk
		1726	$_[0]->unshift_read (chunk => $len, sub {
		1727	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1728	$cb->($_[0], $ref);
		1729	} else {
		1730	$self->_error (Errno::EBADMSG);
		1731	}
		1732	});
		1733	}
		1734
		1735	1
		1736	}
		1737	};
		1738
		1739	=back
		1740
		1741	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
		1742
		1743	Instead of one of the predefined types, you can also specify the name
		1744	of a package. AnyEvent will try to load the package and then expects to
		1745	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1746	progressively tries to load the parent package until it either finds the
		1747	function (good) or runs out of packages (bad).
		1748
		1749	Whenever this type is used, C<push_read> will invoke the function with the
		1750	handle object, the original callback and the remaining arguments.
		1751
		1752	The function is supposed to return a callback (usually a closure) that
		1753	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1754	mentally treat the function as a "configurable read type to read callback"
		1755	converter.
		1756
		1757	It should invoke the original callback when it is done reading (remember
		1758	to pass C<$handle> as first argument as all other callbacks do that,
		1759	although there is no strict requirement on this).
		1760
		1761	For examples, see the source of this module (F<perldoc -m
		1762	AnyEvent::Handle>, search for C<register_read_type>)).
600		1763
601	=item $handle->stop_read	1764	=item $handle->stop_read
602		1765
603	=item $handle->start_read	1766	=item $handle->start_read
604		1767
605	In rare cases you actually do not want to read anything from the	1768	In rare cases you actually do not want to read anything from the
606	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1769	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
607	any queued callbacks will be executed then. To start readign again, call	1770	any queued callbacks will be executed then. To start reading again, call
608	C<start_read>.	1771	C<start_read>.
		1772
		1773	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1774	you change the C<on_read> callback or push/unshift a read callback, and it
		1775	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1776	there are any read requests in the queue.
		1777
		1778	These methods will have no effect when in TLS mode (as TLS doesn't support
		1779	half-duplex connections).
609		1780
610	=cut	1781	=cut
611		1782
612	sub stop_read {	1783	sub stop_read {
613	my ($self) = @_;	1784	my ($self) = @_;
614		1785
615	delete $self->{rw};	1786	delete $self->{_rw} unless $self->{tls};
616	}	1787	}
617		1788
618	sub start_read {	1789	sub start_read {
619	my ($self) = @_;	1790	my ($self) = @_;
620		1791
621	unless ($self->{rw} || $self->{eof}) {	1792	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
622	Scalar::Util::weaken $self;	1793	Scalar::Util::weaken $self;
623		1794
624	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1795	$self->{_rw} = AE::io $self->{fh}, 0, sub {
625	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1796	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
626	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1797	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
627		1798
628	if ($len > 0) {	1799	if ($len > 0) {
629	$self->{filter_r}	1800	$self->{_activity} = $self->{_ractivity} = AE::now;
630	? $self->{filter_r}->($self, $rbuf)	1801
		1802	if ($self->{tls}) {
		1803	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1804
		1805	&_dotls ($self);
		1806	} else {
631	: $self->_drain_rbuf;	1807	$self->_drain_rbuf;
		1808	}
		1809
		1810	if ($len == $self->{read_size}) {
		1811	$self->{read_size} *= 2;
		1812	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		1813	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		1814	}
632		1815
633	} elsif (defined $len) {	1816	} elsif (defined $len) {
634	delete $self->{rw};	1817	delete $self->{_rw};
635	$self->{eof} = 1;	1818	$self->{_eof} = 1;
636	$self->_drain_rbuf;	1819	$self->_drain_rbuf;
637		1820
638	} elsif ($! != EAGAIN && $! != EINTR) {	1821	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
639	return $self->error;	1822	return $self->_error ($!, 1);
640	}	1823	}
641	});	1824	};
642	}	1825	}
643	}	1826	}
644		1827
		1828	our $ERROR_SYSCALL;
		1829	our $ERROR_WANT_READ;
		1830
		1831	sub _tls_error {
		1832	my ($self, $err) = @_;
		1833
		1834	return $self->_error ($!, 1)
		1835	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1836
		1837	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1838
		1839	# reduce error string to look less scary
		1840	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1841
		1842	if ($self->{_on_starttls}) {
		1843	(delete $self->{_on_starttls})->($self, undef, $err);
		1844	&_freetls;
		1845	} else {
		1846	&_freetls;
		1847	$self->_error (Errno::EPROTO, 1, $err);
		1848	}
		1849	}
		1850
		1851	# poll the write BIO and send the data if applicable
		1852	# also decode read data if possible
		1853	# this is basiclaly our TLS state machine
		1854	# more efficient implementations are possible with openssl,
		1855	# but not with the buggy and incomplete Net::SSLeay.
645	sub _dotls {	1856	sub _dotls {
646	my ($self) = @_;	1857	my ($self) = @_;
647		1858
		1859	my $tmp;
		1860
648	if (length $self->{tls_wbuf}) {	1861	if (length $self->{_tls_wbuf}) {
649	my $len = Net::SSLeay::write ($self->{tls}, $self->{tls_wbuf});	1862	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
650	substr $self->{tls_wbuf}, 0, $len, "" if $len > 0;	1863	substr $self->{_tls_wbuf}, 0, $tmp, "";
651	}	1864	}
652		1865
		1866	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1867	return $self->_tls_error ($tmp)
		1868	if $tmp != $ERROR_WANT_READ
		1869	&& ($tmp != $ERROR_SYSCALL || $!);
		1870	}
		1871
653	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{tls_wbio}))) {	1872	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1873	unless (length $tmp) {
		1874	$self->{_on_starttls}
		1875	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1876	&_freetls;
		1877
		1878	if ($self->{on_stoptls}) {
		1879	$self->{on_stoptls}($self);
		1880	return;
		1881	} else {
		1882	# let's treat SSL-eof as we treat normal EOF
		1883	delete $self->{_rw};
		1884	$self->{_eof} = 1;
		1885	}
		1886	}
		1887
		1888	$self->{_tls_rbuf} .= $tmp;
		1889	$self->_drain_rbuf;
		1890	$self->{tls} or return; # tls session might have gone away in callback
		1891	}
		1892
		1893	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1894	return $self->_tls_error ($tmp)
		1895	if $tmp != $ERROR_WANT_READ
		1896	&& ($tmp != $ERROR_SYSCALL || $!);
		1897
		1898	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
654	$self->{wbuf} .= $buf;	1899	$self->{wbuf} .= $tmp;
655	$self->_drain_wbuf;	1900	$self->_drain_wbuf;
		1901	$self->{tls} or return; # tls session might have gone away in callback
656	}	1902	}
657		1903
658	if (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {	1904	$self->{_on_starttls}
659	$self->{rbuf} .= $buf;	1905	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
660	$self->_drain_rbuf;	1906	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
661	} elsif (	1907	}
662	(my $err = Net::SSLeay::get_error ($self->{tls}, -1))	1908
		1909	=item $handle->starttls ($tls[, $tls_ctx])
		1910
		1911	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1912	object is created, you can also do that at a later time by calling
		1913	C<starttls>.
		1914
		1915	Starting TLS is currently an asynchronous operation - when you push some
		1916	write data and then call C<< ->starttls >> then TLS negotiation will start
		1917	immediately, after which the queued write data is then sent.
		1918
		1919	The first argument is the same as the C<tls> constructor argument (either
		1920	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1921
		1922	The second argument is the optional C<AnyEvent::TLS> object that is used
		1923	when AnyEvent::Handle has to create its own TLS connection object, or
		1924	a hash reference with C<< key => value >> pairs that will be used to
		1925	construct a new context.
		1926
		1927	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1928	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1929	changed to your liking. Note that the handshake might have already started
		1930	when this function returns.
		1931
		1932	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1933	handshakes on the same stream. It is best to not attempt to use the
		1934	stream after stopping TLS.
		1935
		1936	This method may invoke callbacks (and therefore the handle might be
		1937	destroyed after it returns).
		1938
		1939	=cut
		1940
		1941	our %TLS_CACHE; #TODO not yet documented, should we?
		1942
		1943	sub starttls {
		1944	my ($self, $tls, $ctx) = @_;
		1945
		1946	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1947	if $self->{tls};
		1948
		1949	$self->{tls} = $tls;
		1950	$self->{tls_ctx} = $ctx if @_ > 2;
		1951
		1952	return unless $self->{fh};
		1953
		1954	require Net::SSLeay;
		1955
		1956	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
663	!= Net::SSLeay::ERROR_WANT_READ ()	1957	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
664	) {	1958
665	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {	1959	$tls = delete $self->{tls};
666	$self->error;	1960	$ctx = $self->{tls_ctx};
667	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {	1961
668	$! = &Errno::EIO;	1962	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
669	$self->error;	1963
		1964	if ("HASH" eq ref $ctx) {
		1965	require AnyEvent::TLS;
		1966
		1967	if ($ctx->{cache}) {
		1968	my $key = $ctx+0;
		1969	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1970	} else {
		1971	$ctx = new AnyEvent::TLS %$ctx;
670	}	1972	}
671		1973	}
672	# all others are fine for our purposes
673	}	1974
674	}	1975	$self->{tls_ctx} = $ctx || TLS_CTX ();
		1976	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
675		1977
676	# TODO: maybe document...	1978	# basically, this is deep magic (because SSL_read should have the same issues)
677	sub starttls {	1979	# but the openssl maintainers basically said: "trust us, it just works".
678	my ($self, $ssl, $ctx) = @_;	1980	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
679		1981	# and mismaintained ssleay-module doesn't even offer them).
680	if ($ssl eq "accept") {	1982	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
681	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
682	Net::SSLeay::set_accept_state ($ssl);
683	} elsif ($ssl eq "connect") {
684	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
685	Net::SSLeay::set_connect_state ($ssl);
686	}	1983	#
		1984	# in short: this is a mess.
		1985	#
		1986	# note that we do not try to keep the length constant between writes as we are required to do.
		1987	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1988	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1989	# have identity issues in that area.
		1990	# Net::SSLeay::CTX_set_mode ($ssl,
		1991	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1992	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1993	Net::SSLeay::CTX_set_mode ($tls, 1|2);
687		1994
688	$self->{tls} = $ssl;
689
690	$self->{tls_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1995	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
691	$self->{tls_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1996	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
692		1997
		1998	Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf});
		1999
693	Net::SSLeay::set_bio ($ssl, $self->{tls_rbio}, $self->{tls_wbio});	2000	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
694		2001
695	$self->{filter_w} = sub {	2002	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
696	$_[0]{tls_wbuf} .= ${$_[1]};	2003	if $self->{on_starttls};
		2004
		2005	&_dotls; # need to trigger the initial handshake
		2006	$self->start_read; # make sure we actually do read
		2007	}
		2008
		2009	=item $handle->stoptls
		2010
		2011	Shuts down the SSL connection - this makes a proper EOF handshake by
		2012	sending a close notify to the other side, but since OpenSSL doesn't
		2013	support non-blocking shut downs, it is not guaranteed that you can re-use
		2014	the stream afterwards.
		2015
		2016	This method may invoke callbacks (and therefore the handle might be
		2017	destroyed after it returns).
		2018
		2019	=cut
		2020
		2021	sub stoptls {
		2022	my ($self) = @_;
		2023
		2024	if ($self->{tls} && $self->{fh}) {
		2025	Net::SSLeay::shutdown ($self->{tls});
		2026
697	&_dotls;	2027	&_dotls;
		2028
		2029	# # we don't give a shit. no, we do, but we can't. no...#d#
		2030	# # we, we... have to use openssl :/#d#
		2031	# &_freetls;#d#
		2032	}
		2033	}
		2034
		2035	sub _freetls {
		2036	my ($self) = @_;
		2037
		2038	return unless $self->{tls};
		2039
		2040	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2041	if $self->{tls} > 0;
		2042
		2043	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		2044	}
		2045
		2046	sub DESTROY {
		2047	my ($self) = @_;
		2048
		2049	&_freetls;
		2050
		2051	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		2052
		2053	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2054	my $fh = delete $self->{fh};
		2055	my $wbuf = delete $self->{wbuf};
		2056
		2057	my @linger;
		2058
		2059	push @linger, AE::io $fh, 1, sub {
		2060	my $len = syswrite $fh, $wbuf, length $wbuf;
		2061
		2062	if ($len > 0) {
		2063	substr $wbuf, 0, $len, "";
		2064	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
		2065	@linger = (); # end
		2066	}
		2067	};
		2068	push @linger, AE::timer $linger, 0, sub {
		2069	@linger = ();
		2070	};
		2071	}
		2072	}
		2073
		2074	=item $handle->destroy
		2075
		2076	Shuts down the handle object as much as possible - this call ensures that
		2077	no further callbacks will be invoked and as many resources as possible
		2078	will be freed. Any method you will call on the handle object after
		2079	destroying it in this way will be silently ignored (and it will return the
		2080	empty list).
		2081
		2082	Normally, you can just "forget" any references to an AnyEvent::Handle
		2083	object and it will simply shut down. This works in fatal error and EOF
		2084	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2085	callback, so when you want to destroy the AnyEvent::Handle object from
		2086	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2087	that case.
		2088
		2089	Destroying the handle object in this way has the advantage that callbacks
		2090	will be removed as well, so if those are the only reference holders (as
		2091	is common), then one doesn't need to do anything special to break any
		2092	reference cycles.
		2093
		2094	The handle might still linger in the background and write out remaining
		2095	data, as specified by the C<linger> option, however.
		2096
		2097	=cut
		2098
		2099	sub destroy {
		2100	my ($self) = @_;
		2101
		2102	$self->DESTROY;
		2103	%$self = ();
		2104	bless $self, "AnyEvent::Handle::destroyed";
		2105	}
		2106
		2107	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2108	#nop
		2109	}
		2110
		2111	=item $handle->destroyed
		2112
		2113	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2114	->destroy >>, true otherwise.
		2115
		2116	Can be useful to decide whether the handle is still valid after some
		2117	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2118	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2119	can destroy the handle, so work can be avoided by checking sometimes:
		2120
		2121	$hdl->starttls ("accept");
		2122	return if $hdl->destroyed;
		2123	$hdl->push_write (...
		2124
		2125	Note that the call to C<push_write> will silently be ignored if the handle
		2126	has been destroyed, so often you can just ignore the possibility of the
		2127	handle being destroyed.
		2128
		2129	=cut
		2130
		2131	sub destroyed { 0 }
		2132	sub AnyEvent::Handle::destroyed::destroyed { 1 }
		2133
		2134	=item AnyEvent::Handle::TLS_CTX
		2135
		2136	This function creates and returns the AnyEvent::TLS object used by default
		2137	for TLS mode.
		2138
		2139	The context is created by calling L<AnyEvent::TLS> without any arguments.
		2140
		2141	=cut
		2142
		2143	our $TLS_CTX;
		2144
		2145	sub TLS_CTX() {
		2146	$TLS_CTX ||= do {
		2147	require AnyEvent::TLS;
		2148
		2149	new AnyEvent::TLS
		2150	}
		2151	}
		2152
		2153	=back
		2154
		2155
		2156	=head1 NONFREQUENTLY ASKED QUESTIONS
		2157
		2158	=over 4
		2159
		2160	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2161	still get further invocations!
		2162
		2163	That's because AnyEvent::Handle keeps a reference to itself when handling
		2164	read or write callbacks.
		2165
		2166	It is only safe to "forget" the reference inside EOF or error callbacks,
		2167	from within all other callbacks, you need to explicitly call the C<<
		2168	->destroy >> method.
		2169
		2170	=item Why is my C<on_eof> callback never called?
		2171
		2172	Probably because your C<on_error> callback is being called instead: When
		2173	you have outstanding requests in your read queue, then an EOF is
		2174	considered an error as you clearly expected some data.
		2175
		2176	To avoid this, make sure you have an empty read queue whenever your handle
		2177	is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
		2178	an C<on_read> handler that simply pushes the first read requests in the
		2179	queue.
		2180
		2181	See also the next question, which explains this in a bit more detail.
		2182
		2183	=item How can I serve requests in a loop?
		2184
		2185	Most protocols consist of some setup phase (authentication for example)
		2186	followed by a request handling phase, where the server waits for requests
		2187	and handles them, in a loop.
		2188
		2189	There are two important variants: The first (traditional, better) variant
		2190	handles requests until the server gets some QUIT command, causing it to
		2191	close the connection first (highly desirable for a busy TCP server). A
		2192	client dropping the connection is an error, which means this variant can
		2193	detect an unexpected detection close.
		2194
		2195	To handle this case, always make sure you have a on-empty read queue, by
		2196	pushing the "read request start" handler on it:
		2197
		2198	# we assume a request starts with a single line
		2199	my @start_request; @start_request = (line => sub {
		2200	my ($hdl, $line) = @_;
		2201
		2202	... handle request
		2203
		2204	# push next request read, possibly from a nested callback
		2205	$hdl->push_read (@start_request);
		2206	});
		2207
		2208	# auth done, now go into request handling loop
		2209	# now push the first @start_request
		2210	$hdl->push_read (@start_request);
		2211
		2212	By always having an outstanding C<push_read>, the handle always expects
		2213	some data and raises the C<EPIPE> error when the connction is dropped
		2214	unexpectedly.
		2215
		2216	The second variant is a protocol where the client can drop the connection
		2217	at any time. For TCP, this means that the server machine may run out of
		2218	sockets easier, and in general, it means you cnanot distinguish a protocl
		2219	failure/client crash from a normal connection close. Nevertheless, these
		2220	kinds of protocols are common (and sometimes even the best solution to the
		2221	problem).
		2222
		2223	Having an outstanding read request at all times is possible if you ignore
		2224	C<EPIPE> errors, but this doesn't help with when the client drops the
		2225	connection during a request, which would still be an error.
		2226
		2227	A better solution is to push the initial request read in an C<on_read>
		2228	callback. This avoids an error, as when the server doesn't expect data
		2229	(i.e. is idly waiting for the next request, an EOF will not raise an
		2230	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2231	and simpler:
		2232
		2233	# auth done, now go into request handling loop
		2234	$hdl->on_read (sub {
		2235	my ($hdl) = @_;
		2236
		2237	# called each time we receive data but the read queue is empty
		2238	# simply start read the request
		2239
		2240	$hdl->push_read (line => sub {
		2241	my ($hdl, $line) = @_;
		2242
		2243	... handle request
		2244
		2245	# do nothing special when the request has been handled, just
		2246	# let the request queue go empty.
		2247	});
		2248	});
		2249
		2250	=item I get different callback invocations in TLS mode/Why can't I pause
		2251	reading?
		2252
		2253	Unlike, say, TCP, TLS connections do not consist of two independent
		2254	communication channels, one for each direction. Or put differently, the
		2255	read and write directions are not independent of each other: you cannot
		2256	write data unless you are also prepared to read, and vice versa.
		2257
		2258	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2259	callback invocations when you are not expecting any read data - the reason
		2260	is that AnyEvent::Handle always reads in TLS mode.
		2261
		2262	During the connection, you have to make sure that you always have a
		2263	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2264	connection (or when you no longer want to use it) you can call the
		2265	C<destroy> method.
		2266
		2267	=item How do I read data until the other side closes the connection?
		2268
		2269	If you just want to read your data into a perl scalar, the easiest way
		2270	to achieve this is by setting an C<on_read> callback that does nothing,
		2271	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2272	will be in C<$_[0]{rbuf}>:
		2273
		2274	$handle->on_read (sub { });
		2275	$handle->on_eof (undef);
		2276	$handle->on_error (sub {
		2277	my $data = delete $_[0]{rbuf};
		2278	});
		2279
		2280	The reason to use C<on_error> is that TCP connections, due to latencies
		2281	and packets loss, might get closed quite violently with an error, when in
		2282	fact all data has been received.
		2283
		2284	It is usually better to use acknowledgements when transferring data,
		2285	to make sure the other side hasn't just died and you got the data
		2286	intact. This is also one reason why so many internet protocols have an
		2287	explicit QUIT command.
		2288
		2289	=item I don't want to destroy the handle too early - how do I wait until
		2290	all data has been written?
		2291
		2292	After writing your last bits of data, set the C<on_drain> callback
		2293	and destroy the handle in there - with the default setting of
		2294	C<low_water_mark> this will be called precisely when all data has been
		2295	written to the socket:
		2296
		2297	$handle->push_write (...);
		2298	$handle->on_drain (sub {
		2299	warn "all data submitted to the kernel\n";
		2300	undef $handle;
		2301	});
		2302
		2303	If you just want to queue some data and then signal EOF to the other side,
		2304	consider using C<< ->push_shutdown >> instead.
		2305
		2306	=item I want to contact a TLS/SSL server, I don't care about security.
		2307
		2308	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2309	connect to it and then create the AnyEvent::Handle with the C<tls>
		2310	parameter:
		2311
		2312	tcp_connect $host, $port, sub {
		2313	my ($fh) = @_;
		2314
		2315	my $handle = new AnyEvent::Handle
		2316	fh => $fh,
		2317	tls => "connect",
		2318	on_error => sub { ... };
		2319
		2320	$handle->push_write (...);
698	};	2321	};
699	$self->{filter_r} = sub {
700	Net::SSLeay::BIO_write ($_[0]{tls_rbio}, ${$_[1]});
701	&_dotls;
702	};
703	}
704		2322
705	sub DESTROY {	2323	=item I want to contact a TLS/SSL server, I do care about security.
706	my $self = shift;
707		2324
708	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	2325	Then you should additionally enable certificate verification, including
709	}	2326	peername verification, if the protocol you use supports it (see
		2327	L<AnyEvent::TLS>, C<verify_peername>).
710		2328
711	=item AnyEvent::Handle::TLS_CTX	2329	E.g. for HTTPS:
712		2330
713	This function creates and returns the Net::SSLeay::CTX object used by	2331	tcp_connect $host, $port, sub {
714	default for TLS mode.	2332	my ($fh) = @_;
715		2333
716	The context is created like this:	2334	my $handle = new AnyEvent::Handle
		2335	fh => $fh,
		2336	peername => $host,
		2337	tls => "connect",
		2338	tls_ctx => { verify => 1, verify_peername => "https" },
		2339	...
717		2340
718	Net::SSLeay::load_error_strings;	2341	Note that you must specify the hostname you connected to (or whatever
719	Net::SSLeay::SSLeay_add_ssl_algorithms;	2342	"peername" the protocol needs) as the C<peername> argument, otherwise no
720	Net::SSLeay::randomize;	2343	peername verification will be done.
721		2344
722	my $CTX = Net::SSLeay::CTX_new;	2345	The above will use the system-dependent default set of trusted CA
		2346	certificates. If you want to check against a specific CA, add the
		2347	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
723		2348
724	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL	2349	tls_ctx => {
		2350	verify => 1,
		2351	verify_peername => "https",
		2352	ca_file => "my-ca-cert.pem",
		2353	},
725		2354
726	=cut	2355	=item I want to create a TLS/SSL server, how do I do that?
727		2356
728	our $TLS_CTX;	2357	Well, you first need to get a server certificate and key. You have
		2358	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2359	self-signed certificate (cheap. check the search engine of your choice,
		2360	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2361	nice program for that purpose).
729		2362
730	sub TLS_CTX() {	2363	Then create a file with your private key (in PEM format, see
731	$TLS_CTX || do {	2364	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
732	require Net::SSLeay;	2365	file should then look like this:
733		2366
734	Net::SSLeay::load_error_strings ();	2367	-----BEGIN RSA PRIVATE KEY-----
735	Net::SSLeay::SSLeay_add_ssl_algorithms ();	2368	...header data
736	Net::SSLeay::randomize ();	2369	... lots of base64'y-stuff
		2370	-----END RSA PRIVATE KEY-----
737		2371
738	$TLS_CTX = Net::SSLeay::CTX_new ();	2372	-----BEGIN CERTIFICATE-----
		2373	... lots of base64'y-stuff
		2374	-----END CERTIFICATE-----
739		2375
740	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());	2376	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2377	specify this file as C<cert_file>:
741		2378
742	$TLS_CTX	2379	tcp_server undef, $port, sub {
743	}	2380	my ($fh) = @_;
744	}	2381
		2382	my $handle = new AnyEvent::Handle
		2383	fh => $fh,
		2384	tls => "accept",
		2385	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2386	...
		2387
		2388	When you have intermediate CA certificates that your clients might not
		2389	know about, just append them to the C<cert_file>.
745		2390
746	=back	2391	=back
747		2392
		2393
		2394	=head1 SUBCLASSING AnyEvent::Handle
		2395
		2396	In many cases, you might want to subclass AnyEvent::Handle.
		2397
		2398	To make this easier, a given version of AnyEvent::Handle uses these
		2399	conventions:
		2400
		2401	=over 4
		2402
		2403	=item * all constructor arguments become object members.
		2404
		2405	At least initially, when you pass a C<tls>-argument to the constructor it
		2406	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2407	mutated later on (for example C<tls> will hold the TLS connection object).
		2408
		2409	=item * other object member names are prefixed with an C<_>.
		2410
		2411	All object members not explicitly documented (internal use) are prefixed
		2412	with an underscore character, so the remaining non-C<_>-namespace is free
		2413	for use for subclasses.
		2414
		2415	=item * all members not documented here and not prefixed with an underscore
		2416	are free to use in subclasses.
		2417
		2418	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2419	member variables, but that's just life. At least it is documented.
		2420
		2421	=back
		2422
748	=head1 AUTHOR	2423	=head1 AUTHOR
749		2424
750	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	2425	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
751		2426
752	=cut	2427	=cut

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