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Revision 1.208 by root, Sun Dec 5 11:41:45 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 file handles 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>, C<EPIPE> or C<EBADMSG>).	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 autocork => <boolean>
		285
		286	When disabled (the default), C<push_write> will try to immediately
		287	write the data to the handle if possible. This avoids having to register
		288	a write watcher and wait for the next event loop iteration, but can
		289	be inefficient if you write multiple small chunks (on the wire, this
		290	disadvantage is usually avoided by your kernel's nagle algorithm, see
		291	C<no_delay>, but this option can save costly syscalls).
		292
		293	When enabled, writes will always be queued till the next event loop
		294	iteration. This is efficient when you do many small writes per iteration,
		295	but less efficient when you do a single write only per iteration (or when
		296	the write buffer often is full). It also increases write latency.
		297
		298	=item no_delay => <boolean>
		299
		300	When doing small writes on sockets, your operating system kernel might
		301	wait a bit for more data before actually sending it out. This is called
		302	the Nagle algorithm, and usually it is beneficial.
		303
		304	In some situations you want as low a delay as possible, which can be
		305	accomplishd by setting this option to a true value.
		306
		307	The default is your operating system's default behaviour (most likely
		308	enabled). This option explicitly enables or disables it, if possible.
		309
		310	=item keepalive => <boolean>
		311
		312	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		313	normally, TCP connections have no time-out once established, so TCP
		314	connections, once established, can stay alive forever even when the other
		315	side has long gone. TCP keepalives are a cheap way to take down long-lived
		316	TCP connections when the other side becomes unreachable. While the default
		317	is OS-dependent, TCP keepalives usually kick in after around two hours,
		318	and, if the other side doesn't reply, take down the TCP connection some 10
		319	to 15 minutes later.
		320
		321	It is harmless to specify this option for file handles that do not support
		322	keepalives, and enabling it on connections that are potentially long-lived
		323	is usually a good idea.
		324
		325	=item oobinline => <boolean>
		326
		327	BSD majorly fucked up the implementation of TCP urgent data. The result
		328	is that almost no OS implements TCP according to the specs, and every OS
		329	implements it slightly differently.
		330
		331	If you want to handle TCP urgent data, then setting this flag (the default
		332	is enabled) gives you the most portable way of getting urgent data, by
		333	putting it into the stream.
		334
		335	Since BSD emulation of OOB data on top of TCP's urgent data can have
		336	security implications, AnyEvent::Handle sets this flag automatically
		337	unless explicitly specified. Note that setting this flag after
		338	establishing a connection I<may> be a bit too late (data loss could
		339	already have occured on BSD systems), but at least it will protect you
		340	from most attacks.
		341
133	=item read_size => <bytes>	342	=item read_size => <bytes>
134		343
135	The default read block size (the amount of bytes this module will try to read	344	The initial read block size, the number of bytes this module will try to
136	on each [loop iteration). Default: C<4096>.	345	read during each loop iteration. Each handle object will consume at least
		346	this amount of memory for the read buffer as well, so when handling many
		347	connections requirements). See also C<max_read_size>. Default: C<2048>.
		348
		349	=item max_read_size => <bytes>
		350
		351	The maximum read buffer size used by the dynamic adjustment
		352	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		353	one go it will double C<read_size> up to the maximum given by this
		354	option. Default: C<131072> or C<read_size>, whichever is higher.
137		355
138	=item low_water_mark => <bytes>	356	=item low_water_mark => <bytes>
139		357
140	Sets the amount of bytes (default: C<0>) that make up an "empty" write	358	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	359	buffer: If the buffer reaches this size or gets even samller it is
142	considered empty.	360	considered empty.
143		361
		362	Sometimes it can be beneficial (for performance reasons) to add data to
		363	the write buffer before it is fully drained, but this is a rare case, as
		364	the operating system kernel usually buffers data as well, so the default
		365	is good in almost all cases.
		366
		367	=item linger => <seconds>
		368
		369	If this is non-zero (default: C<3600>), the destructor of the
		370	AnyEvent::Handle object will check whether there is still outstanding
		371	write data and will install a watcher that will write this data to the
		372	socket. No errors will be reported (this mostly matches how the operating
		373	system treats outstanding data at socket close time).
		374
		375	This will not work for partial TLS data that could not be encoded
		376	yet. This data will be lost. Calling the C<stoptls> method in time might
		377	help.
		378
		379	=item peername => $string
		380
		381	A string used to identify the remote site - usually the DNS hostname
		382	(I<not> IDN!) used to create the connection, rarely the IP address.
		383
		384	Apart from being useful in error messages, this string is also used in TLS
		385	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		386	verification will be skipped when C<peername> is not specified or is
		387	C<undef>.
		388
144	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	389	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
145		390
146	When this parameter is given, it enables TLS (SSL) mode, that means it	391	When this parameter is given, it enables TLS (SSL) mode, that means
147	will start making tls handshake and will transparently encrypt/decrypt	392	AnyEvent will start a TLS handshake as soon as the connection has been
148	data.	393	established and will transparently encrypt/decrypt data afterwards.
		394
		395	All TLS protocol errors will be signalled as C<EPROTO>, with an
		396	appropriate error message.
149		397
150	TLS mode requires Net::SSLeay to be installed (it will be loaded	398	TLS mode requires Net::SSLeay to be installed (it will be loaded
151	automatically when you try to create a TLS handle).	399	automatically when you try to create a TLS handle): this module doesn't
		400	have a dependency on that module, so if your module requires it, you have
		401	to add the dependency yourself.
152		402
153	For the TLS server side, use C<accept>, and for the TLS client side of a	403	Unlike TCP, TLS has a server and client side: for the TLS server side, use
154	connection, use C<connect> mode.	404	C<accept>, and for the TLS client side of a connection, use C<connect>
		405	mode.
155		406
156	You can also provide your own TLS connection object, but you have	407	You can also provide your own TLS connection object, but you have
157	to make sure that you call either C<Net::SSLeay::set_connect_state>	408	to make sure that you call either C<Net::SSLeay::set_connect_state>
158	or C<Net::SSLeay::set_accept_state> on it before you pass it to	409	or C<Net::SSLeay::set_accept_state> on it before you pass it to
159	AnyEvent::Handle.	410	AnyEvent::Handle. Also, this module will take ownership of this connection
		411	object.
160		412
		413	At some future point, AnyEvent::Handle might switch to another TLS
		414	implementation, then the option to use your own session object will go
		415	away.
		416
		417	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		418	passing in the wrong integer will lead to certain crash. This most often
		419	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		420	segmentation fault.
		421
161	See the C<starttls> method if you need to start TLs negotiation later.	422	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
162		423
163	=item tls_ctx => $ssl_ctx	424	=item tls_ctx => $anyevent_tls
164		425
165	Use the given Net::SSLeay::CTX object to create the new TLS connection	426	Use the given C<AnyEvent::TLS> object to create the new TLS connection
166	(unless a connection object was specified directly). If this parameter is	427	(unless a connection object was specified directly). If this
167	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	428	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		429	C<AnyEvent::Handle::TLS_CTX>.
		430
		431	Instead of an object, you can also specify a hash reference with C<< key
		432	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		433	new TLS context object.
		434
		435	=item on_starttls => $cb->($handle, $success[, $error_message])
		436
		437	This callback will be invoked when the TLS/SSL handshake has finished. If
		438	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		439	(C<on_stoptls> will not be called in this case).
		440
		441	The session in C<< $handle->{tls} >> can still be examined in this
		442	callback, even when the handshake was not successful.
		443
		444	TLS handshake failures will not cause C<on_error> to be invoked when this
		445	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		446
		447	Without this callback, handshake failures lead to C<on_error> being
		448	called as usual.
		449
		450	Note that you cannot just call C<starttls> again in this callback. If you
		451	need to do that, start an zero-second timer instead whose callback can
		452	then call C<< ->starttls >> again.
		453
		454	=item on_stoptls => $cb->($handle)
		455
		456	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		457	set, then it will be invoked after freeing the TLS session. If it is not,
		458	then a TLS shutdown condition will be treated like a normal EOF condition
		459	on the handle.
		460
		461	The session in C<< $handle->{tls} >> can still be examined in this
		462	callback.
		463
		464	This callback will only be called on TLS shutdowns, not when the
		465	underlying handle signals EOF.
		466
		467	=item json => JSON or JSON::XS object
		468
		469	This is the json coder object used by the C<json> read and write types.
		470
		471	If you don't supply it, then AnyEvent::Handle will create and use a
		472	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		473	texts.
		474
		475	Note that you are responsible to depend on the JSON module if you want to
		476	use this functionality, as AnyEvent does not have a dependency itself.
168		477
169	=back	478	=back
170		479
171	=cut	480	=cut
172
173	our (%RH, %WH);
174
175	sub register_read_type($$) {
176	$RH{$_[0]} = $_[1];
177	}
178
179	sub register_write_type($$) {
180	$WH{$_[0]} = $_[1];
181	}
182		481
183	sub new {	482	sub new {
184	my $class = shift;	483	my $class = shift;
185
186	my $self = bless { @_ }, $class;	484	my $self = bless { @_ }, $class;
187		485
188	$self->{fh} or Carp::croak "mandatory argument fh is missing";	486	if ($self->{fh}) {
		487	$self->_start;
		488	return unless $self->{fh}; # could be gone by now
		489
		490	} elsif ($self->{connect}) {
		491	require AnyEvent::Socket;
		492
		493	$self->{peername} = $self->{connect}[0]
		494	unless exists $self->{peername};
		495
		496	$self->{_skip_drain_rbuf} = 1;
		497
		498	{
		499	Scalar::Util::weaken (my $self = $self);
		500
		501	$self->{_connect} =
		502	AnyEvent::Socket::tcp_connect (
		503	$self->{connect}[0],
		504	$self->{connect}[1],
		505	sub {
		506	my ($fh, $host, $port, $retry) = @_;
		507
		508	delete $self->{_connect}; # no longer needed
		509
		510	if ($fh) {
		511	$self->{fh} = $fh;
		512
		513	delete $self->{_skip_drain_rbuf};
		514	$self->_start;
		515
		516	$self->{on_connect}
		517	and $self->{on_connect}($self, $host, $port, sub {
		518	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		519	$self->{_skip_drain_rbuf} = 1;
		520	&$retry;
		521	});
		522
		523	} else {
		524	if ($self->{on_connect_error}) {
		525	$self->{on_connect_error}($self, "$!");
		526	$self->destroy;
		527	} else {
		528	$self->_error ($!, 1);
		529	}
		530	}
		531	},
		532	sub {
		533	local $self->{fh} = $_[0];
		534
		535	$self->{on_prepare}
		536	? $self->{on_prepare}->($self)
		537	: ()
		538	}
		539	);
		540	}
		541
		542	} else {
		543	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		544	}
		545
		546	$self
		547	}
		548
		549	sub _start {
		550	my ($self) = @_;
		551
		552	# too many clueless people try to use udp and similar sockets
		553	# with AnyEvent::Handle, do them a favour.
		554	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		555	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		556	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
189		557
190	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	558	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
191		559
192	if ($self->{tls}) {	560	$self->{_activity} =
193	require Net::SSLeay;	561	$self->{_ractivity} =
		562	$self->{_wactivity} = AE::now;
		563
		564	$self->{read_size} ||= 2048;
		565	$self->{max_read_size} = $self->{read_size}
		566	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		567
		568	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		569	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		570	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		571
		572	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		573	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		574
		575	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		576
194	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	577	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
195	}	578	if $self->{tls};
196		579
197	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
198	$self->on_error (delete $self->{on_error}) if $self->{on_error};
199	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	580	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
200	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
201		581
202	$self->start_read;	582	$self->start_read
		583	if $self->{on_read} || @{ $self->{_queue} };
203		584
204	$self	585	$self->_drain_wbuf;
205	}	586	}
206		587
207	sub _shutdown {
208	my ($self) = @_;
209
210	delete $self->{rw};
211	delete $self->{ww};
212	delete $self->{fh};
213	}
214
215	sub error {	588	sub _error {
216	my ($self) = @_;	589	my ($self, $errno, $fatal, $message) = @_;
217		590
218	{	591	$! = $errno;
219	local $!;	592	$message ||= "$!";
220	$self->_shutdown;
221	}
222		593
223	if ($self->{on_error}) {	594	if ($self->{on_error}) {
224	$self->{on_error}($self);	595	$self->{on_error}($self, $fatal, $message);
225	} else {	596	$self->destroy if $fatal;
		597	} elsif ($self->{fh} || $self->{connect}) {
		598	$self->destroy;
226	Carp::croak "AnyEvent::Handle uncaught fatal error: $!";	599	Carp::croak "AnyEvent::Handle uncaught error: $message";
227	}	600	}
228	}	601	}
229		602
230	=item $fh = $handle->fh	603	=item $fh = $handle->fh
231		604
232	This method returns the file handle of the L<AnyEvent::Handle> object.	605	This method returns the file handle used to create the L<AnyEvent::Handle> object.
233		606
234	=cut	607	=cut
235		608
236	sub fh { $_[0]->{fh} }	609	sub fh { $_[0]{fh} }
237		610
238	=item $handle->on_error ($cb)	611	=item $handle->on_error ($cb)
239		612
240	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	613	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
241		614
…		…
253		626
254	sub on_eof {	627	sub on_eof {
255	$_[0]{on_eof} = $_[1];	628	$_[0]{on_eof} = $_[1];
256	}	629	}
257		630
		631	=item $handle->on_timeout ($cb)
		632
		633	=item $handle->on_rtimeout ($cb)
		634
		635	=item $handle->on_wtimeout ($cb)
		636
		637	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		638	callback, or disables the callback (but not the timeout) if C<$cb> =
		639	C<undef>. See the C<timeout> constructor argument and method.
		640
		641	=cut
		642
		643	# see below
		644
		645	=item $handle->autocork ($boolean)
		646
		647	Enables or disables the current autocork behaviour (see C<autocork>
		648	constructor argument). Changes will only take effect on the next write.
		649
		650	=cut
		651
		652	sub autocork {
		653	$_[0]{autocork} = $_[1];
		654	}
		655
		656	=item $handle->no_delay ($boolean)
		657
		658	Enables or disables the C<no_delay> setting (see constructor argument of
		659	the same name for details).
		660
		661	=cut
		662
		663	sub no_delay {
		664	$_[0]{no_delay} = $_[1];
		665
		666	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		667	if $_[0]{fh};
		668	}
		669
		670	=item $handle->keepalive ($boolean)
		671
		672	Enables or disables the C<keepalive> setting (see constructor argument of
		673	the same name for details).
		674
		675	=cut
		676
		677	sub keepalive {
		678	$_[0]{keepalive} = $_[1];
		679
		680	eval {
		681	local $SIG{__DIE__};
		682	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		683	if $_[0]{fh};
		684	};
		685	}
		686
		687	=item $handle->oobinline ($boolean)
		688
		689	Enables or disables the C<oobinline> setting (see constructor argument of
		690	the same name for details).
		691
		692	=cut
		693
		694	sub oobinline {
		695	$_[0]{oobinline} = $_[1];
		696
		697	eval {
		698	local $SIG{__DIE__};
		699	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		700	if $_[0]{fh};
		701	};
		702	}
		703
		704	=item $handle->keepalive ($boolean)
		705
		706	Enables or disables the C<keepalive> setting (see constructor argument of
		707	the same name for details).
		708
		709	=cut
		710
		711	sub keepalive {
		712	$_[0]{keepalive} = $_[1];
		713
		714	eval {
		715	local $SIG{__DIE__};
		716	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		717	if $_[0]{fh};
		718	};
		719	}
		720
		721	=item $handle->on_starttls ($cb)
		722
		723	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		724
		725	=cut
		726
		727	sub on_starttls {
		728	$_[0]{on_starttls} = $_[1];
		729	}
		730
		731	=item $handle->on_stoptls ($cb)
		732
		733	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		734
		735	=cut
		736
		737	sub on_stoptls {
		738	$_[0]{on_stoptls} = $_[1];
		739	}
		740
		741	=item $handle->rbuf_max ($max_octets)
		742
		743	Configures the C<rbuf_max> setting (C<undef> disables it).
		744
		745	=cut
		746
		747	sub rbuf_max {
		748	$_[0]{rbuf_max} = $_[1];
		749	}
		750
		751	#############################################################################
		752
		753	=item $handle->timeout ($seconds)
		754
		755	=item $handle->rtimeout ($seconds)
		756
		757	=item $handle->wtimeout ($seconds)
		758
		759	Configures (or disables) the inactivity timeout.
		760
		761	=item $handle->timeout_reset
		762
		763	=item $handle->rtimeout_reset
		764
		765	=item $handle->wtimeout_reset
		766
		767	Reset the activity timeout, as if data was received or sent.
		768
		769	These methods are cheap to call.
		770
		771	=cut
		772
		773	for my $dir ("", "r", "w") {
		774	my $timeout = "${dir}timeout";
		775	my $tw = "_${dir}tw";
		776	my $on_timeout = "on_${dir}timeout";
		777	my $activity = "_${dir}activity";
		778	my $cb;
		779
		780	*$on_timeout = sub {
		781	$_[0]{$on_timeout} = $_[1];
		782	};
		783
		784	*$timeout = sub {
		785	my ($self, $new_value) = @_;
		786
		787	$new_value >= 0
		788	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		789
		790	$self->{$timeout} = $new_value;
		791	delete $self->{$tw}; &$cb;
		792	};
		793
		794	*{"${dir}timeout_reset"} = sub {
		795	$_[0]{$activity} = AE::now;
		796	};
		797
		798	# main workhorse:
		799	# reset the timeout watcher, as neccessary
		800	# also check for time-outs
		801	$cb = sub {
		802	my ($self) = @_;
		803
		804	if ($self->{$timeout} && $self->{fh}) {
		805	my $NOW = AE::now;
		806
		807	# when would the timeout trigger?
		808	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		809
		810	# now or in the past already?
		811	if ($after <= 0) {
		812	$self->{$activity} = $NOW;
		813
		814	if ($self->{$on_timeout}) {
		815	$self->{$on_timeout}($self);
		816	} else {
		817	$self->_error (Errno::ETIMEDOUT);
		818	}
		819
		820	# callback could have changed timeout value, optimise
		821	return unless $self->{$timeout};
		822
		823	# calculate new after
		824	$after = $self->{$timeout};
		825	}
		826
		827	Scalar::Util::weaken $self;
		828	return unless $self; # ->error could have destroyed $self
		829
		830	$self->{$tw} ||= AE::timer $after, 0, sub {
		831	delete $self->{$tw};
		832	$cb->($self);
		833	};
		834	} else {
		835	delete $self->{$tw};
		836	}
		837	}
		838	}
		839
258	#############################################################################	840	#############################################################################
259		841
260	=back	842	=back
261		843
262	=head2 WRITE QUEUE	844	=head2 WRITE QUEUE
…		…
275	=item $handle->on_drain ($cb)	857	=item $handle->on_drain ($cb)
276		858
277	Sets the C<on_drain> callback or clears it (see the description of	859	Sets the C<on_drain> callback or clears it (see the description of
278	C<on_drain> in the constructor).	860	C<on_drain> in the constructor).
279		861
		862	This method may invoke callbacks (and therefore the handle might be
		863	destroyed after it returns).
		864
280	=cut	865	=cut
281		866
282	sub on_drain {	867	sub on_drain {
283	my ($self, $cb) = @_;	868	my ($self, $cb) = @_;
284		869
285	$self->{on_drain} = $cb;	870	$self->{on_drain} = $cb;
286		871
287	$cb->($self)	872	$cb->($self)
288	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	873	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
289	}	874	}
290		875
291	=item $handle->push_write ($data)	876	=item $handle->push_write ($data)
292		877
293	Queues the given scalar to be written. You can push as much data as you	878	Queues the given scalar to be written. You can push as much data as you
294	want (only limited by the available memory), as C<AnyEvent::Handle>	879	want (only limited by the available memory), as C<AnyEvent::Handle>
295	buffers it independently of the kernel.	880	buffers it independently of the kernel.
296		881
		882	This method may invoke callbacks (and therefore the handle might be
		883	destroyed after it returns).
		884
297	=cut	885	=cut
298		886
299	sub _drain_wbuf {	887	sub _drain_wbuf {
300	my ($self) = @_;	888	my ($self) = @_;
301		889
302	if (!$self->{ww} && length $self->{wbuf}) {	890	if (!$self->{_ww} && length $self->{wbuf}) {
		891
303	Scalar::Util::weaken $self;	892	Scalar::Util::weaken $self;
		893
304	my $cb = sub {	894	my $cb = sub {
305	my $len = syswrite $self->{fh}, $self->{wbuf};	895	my $len = syswrite $self->{fh}, $self->{wbuf};
306		896
307	if ($len >= 0) {	897	if (defined $len) {
308	substr $self->{wbuf}, 0, $len, "";	898	substr $self->{wbuf}, 0, $len, "";
309		899
		900	$self->{_activity} = $self->{_wactivity} = AE::now;
		901
310	$self->{on_drain}($self)	902	$self->{on_drain}($self)
311	if $self->{low_water_mark} >= length $self->{wbuf}	903	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
312	&& $self->{on_drain};	904	&& $self->{on_drain};
313		905
314	delete $self->{ww} unless length $self->{wbuf};	906	delete $self->{_ww} unless length $self->{wbuf};
315	} elsif ($! != EAGAIN && $! != EINTR) {	907	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
316	$self->error;	908	$self->_error ($!, 1);
317	}	909	}
318	};	910	};
319		911
320	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	912	# try to write data immediately
		913	$cb->() unless $self->{autocork};
321		914
322	$cb->($self);	915	# if still data left in wbuf, we need to poll
		916	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		917	if length $self->{wbuf};
323	};	918	};
		919	}
		920
		921	our %WH;
		922
		923	# deprecated
		924	sub register_write_type($$) {
		925	$WH{$_[0]} = $_[1];
324	}	926	}
325		927
326	sub push_write {	928	sub push_write {
327	my $self = shift;	929	my $self = shift;
328		930
329	if (@_ > 1) {	931	if (@_ > 1) {
330	my $type = shift;	932	my $type = shift;
331		933
		934	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
332	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	935	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
333	->($self, @_);	936	->($self, @_);
334	}	937	}
335		938
		939	# we downgrade here to avoid hard-to-track-down bugs,
		940	# and diagnose the problem earlier and better.
		941
336	if ($self->{filter_w}) {	942	if ($self->{tls}) {
337	$self->{filter_w}->($self, \$_[0]);	943	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		944	&_dotls ($self) if $self->{fh};
338	} else {	945	} else {
339	$self->{wbuf} .= $_[0];	946	utf8::downgrade $self->{wbuf} .= $_[0];
340	$self->_drain_wbuf;	947	$self->_drain_wbuf if $self->{fh};
341	}	948	}
342	}	949	}
343		950
344	=item $handle->push_write (type => @args)	951	=item $handle->push_write (type => @args)
345		952
346	=item $handle->unshift_write (type => @args)
347
348	Instead of formatting your data yourself, you can also let this module do	953	Instead of formatting your data yourself, you can also let this module
349	the job by specifying a type and type-specific arguments.	954	do the job by specifying a type and type-specific arguments. You
		955	can also specify the (fully qualified) name of a package, in which
		956	case AnyEvent tries to load the package and then expects to find the
		957	C<anyevent_write_type> function inside (see "custom write types", below).
350		958
351	Predefined types are:	959	Predefined types are (if you have ideas for additional types, feel free to
		960	drop by and tell us):
352		961
353	=over 4	962	=over 4
354		963
355	=item netstring => $string	964	=item netstring => $string
356		965
…		…
360	=cut	969	=cut
361		970
362	register_write_type netstring => sub {	971	register_write_type netstring => sub {
363	my ($self, $string) = @_;	972	my ($self, $string) = @_;
364		973
365	sprintf "%d:%s,", (length $string), $string	974	(length $string) . ":$string,"
366	};	975	};
367		976
		977	=item packstring => $format, $data
		978
		979	An octet string prefixed with an encoded length. The encoding C<$format>
		980	uses the same format as a Perl C<pack> format, but must specify a single
		981	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		982	optional C<!>, C<< < >> or C<< > >> modifier).
		983
		984	=cut
		985
		986	register_write_type packstring => sub {
		987	my ($self, $format, $string) = @_;
		988
		989	pack "$format/a*", $string
		990	};
		991
		992	=item json => $array_or_hashref
		993
		994	Encodes the given hash or array reference into a JSON object. Unless you
		995	provide your own JSON object, this means it will be encoded to JSON text
		996	in UTF-8.
		997
		998	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		999	one end of a handle and read them at the other end without using any
		1000	additional framing.
		1001
		1002	The generated JSON text is guaranteed not to contain any newlines: While
		1003	this module doesn't need delimiters after or between JSON texts to be
		1004	able to read them, many other languages depend on that.
		1005
		1006	A simple RPC protocol that interoperates easily with others is to send
		1007	JSON arrays (or objects, although arrays are usually the better choice as
		1008	they mimic how function argument passing works) and a newline after each
		1009	JSON text:
		1010
		1011	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		1012	$handle->push_write ("\012");
		1013
		1014	An AnyEvent::Handle receiver would simply use the C<json> read type and
		1015	rely on the fact that the newline will be skipped as leading whitespace:
		1016
		1017	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1018
		1019	Other languages could read single lines terminated by a newline and pass
		1020	this line into their JSON decoder of choice.
		1021
		1022	=cut
		1023
		1024	sub json_coder() {
		1025	eval { require JSON::XS; JSON::XS->new->utf8 }
		1026	|| do { require JSON; JSON->new->utf8 }
		1027	}
		1028
		1029	register_write_type json => sub {
		1030	my ($self, $ref) = @_;
		1031
		1032	my $json = $self->{json} ||= json_coder;
		1033
		1034	$json->encode ($ref)
		1035	};
		1036
		1037	=item storable => $reference
		1038
		1039	Freezes the given reference using L<Storable> and writes it to the
		1040	handle. Uses the C<nfreeze> format.
		1041
		1042	=cut
		1043
		1044	register_write_type storable => sub {
		1045	my ($self, $ref) = @_;
		1046
		1047	require Storable;
		1048
		1049	pack "w/a*", Storable::nfreeze ($ref)
		1050	};
		1051
368	=back	1052	=back
369		1053
370	=cut	1054	=item $handle->push_shutdown
371		1055
		1056	Sometimes you know you want to close the socket after writing your data
		1057	before it was actually written. One way to do that is to replace your
		1058	C<on_drain> handler by a callback that shuts down the socket (and set
		1059	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1060	replaces the C<on_drain> callback with:
372		1061
		1062	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		1063
		1064	This simply shuts down the write side and signals an EOF condition to the
		1065	the peer.
		1066
		1067	You can rely on the normal read queue and C<on_eof> handling
		1068	afterwards. This is the cleanest way to close a connection.
		1069
		1070	This method may invoke callbacks (and therefore the handle might be
		1071	destroyed after it returns).
		1072
		1073	=cut
		1074
		1075	sub push_shutdown {
		1076	my ($self) = @_;
		1077
		1078	delete $self->{low_water_mark};
		1079	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1080	}
		1081
		1082	=item custom write types - Package::anyevent_write_type $handle, @args
		1083
		1084	Instead of one of the predefined types, you can also specify the name of
		1085	a package. AnyEvent will try to load the package and then expects to find
		1086	a function named C<anyevent_write_type> inside. If it isn't found, it
		1087	progressively tries to load the parent package until it either finds the
		1088	function (good) or runs out of packages (bad).
		1089
		1090	Whenever the given C<type> is used, C<push_write> will the function with
		1091	the handle object and the remaining arguments.
		1092
		1093	The function is supposed to return a single octet string that will be
		1094	appended to the write buffer, so you cna mentally treat this function as a
		1095	"arguments to on-the-wire-format" converter.
		1096
		1097	Example: implement a custom write type C<join> that joins the remaining
		1098	arguments using the first one.
		1099
		1100	$handle->push_write (My::Type => " ", 1,2,3);
		1101
		1102	# uses the following package, which can be defined in the "My::Type" or in
		1103	# the "My" modules to be auto-loaded, or just about anywhere when the
		1104	# My::Type::anyevent_write_type is defined before invoking it.
		1105
		1106	package My::Type;
		1107
		1108	sub anyevent_write_type {
		1109	my ($handle, $delim, @args) = @_;
		1110
		1111	join $delim, @args
		1112	}
		1113
		1114	=cut
373		1115
374	#############################################################################	1116	#############################################################################
375		1117
376	=back	1118	=back
377		1119
…		…
384	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1126	ways, the "simple" way, using only C<on_read> and the "complex" way, using
385	a queue.	1127	a queue.
386		1128
387	In the simple case, you just install an C<on_read> callback and whenever	1129	In the simple case, you just install an C<on_read> callback and whenever
388	new data arrives, it will be called. You can then remove some data (if	1130	new data arrives, it will be called. You can then remove some data (if
389	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1131	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
390	or not.	1132	leave the data there if you want to accumulate more (e.g. when only a
		1133	partial message has been received so far), or change the read queue with
		1134	e.g. C<push_read>.
391		1135
392	In the more complex case, you want to queue multiple callbacks. In this	1136	In the more complex case, you want to queue multiple callbacks. In this
393	case, AnyEvent::Handle will call the first queued callback each time new	1137	case, AnyEvent::Handle will call the first queued callback each time new
394	data arrives and removes it when it has done its job (see C<push_read>,	1138	data arrives (also the first time it is queued) and remove it when it has
395	below).	1139	done its job (see C<push_read>, below).
396		1140
397	This way you can, for example, push three line-reads, followed by reading	1141	This way you can, for example, push three line-reads, followed by reading
398	a chunk of data, and AnyEvent::Handle will execute them in order.	1142	a chunk of data, and AnyEvent::Handle will execute them in order.
399		1143
400	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1144	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
401	the specified number of bytes which give an XML datagram.	1145	the specified number of bytes which give an XML datagram.
402		1146
403	# in the default state, expect some header bytes	1147	# in the default state, expect some header bytes
404	$handle->on_read (sub {	1148	$handle->on_read (sub {
405	# some data is here, now queue the length-header-read (4 octets)	1149	# some data is here, now queue the length-header-read (4 octets)
406	shift->unshift_read_chunk (4, sub {	1150	shift->unshift_read (chunk => 4, sub {
407	# header arrived, decode	1151	# header arrived, decode
408	my $len = unpack "N", $_[1];	1152	my $len = unpack "N", $_[1];
409		1153
410	# now read the payload	1154	# now read the payload
411	shift->unshift_read_chunk ($len, sub {	1155	shift->unshift_read (chunk => $len, sub {
412	my $xml = $_[1];	1156	my $xml = $_[1];
413	# handle xml	1157	# handle xml
414	});	1158	});
415	});	1159	});
416	});	1160	});
417		1161
418	Example 2: Implement a client for a protocol that replies either with	1162	Example 2: Implement a client for a protocol that replies either with "OK"
419	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1163	and another line or "ERROR" for the first request that is sent, and 64
420	second request. Due tot he availability of a full queue, we can just	1164	bytes for the second request. Due to the availability of a queue, we can
421	pipeline sending both requests and manipulate the queue as necessary in	1165	just pipeline sending both requests and manipulate the queue as necessary
422	the callbacks:	1166	in the callbacks.
423		1167
424	# request one	1168	When the first callback is called and sees an "OK" response, it will
		1169	C<unshift> another line-read. This line-read will be queued I<before> the
		1170	64-byte chunk callback.
		1171
		1172	# request one, returns either "OK + extra line" or "ERROR"
425	$handle->push_write ("request 1\015\012");	1173	$handle->push_write ("request 1\015\012");
426		1174
427	# we expect "ERROR" or "OK" as response, so push a line read	1175	# we expect "ERROR" or "OK" as response, so push a line read
428	$handle->push_read_line (sub {	1176	$handle->push_read (line => sub {
429	# if we got an "OK", we have to _prepend_ another line,	1177	# if we got an "OK", we have to _prepend_ another line,
430	# so it will be read before the second request reads its 64 bytes	1178	# so it will be read before the second request reads its 64 bytes
431	# which are already in the queue when this callback is called	1179	# which are already in the queue when this callback is called
432	# we don't do this in case we got an error	1180	# we don't do this in case we got an error
433	if ($_[1] eq "OK") {	1181	if ($_[1] eq "OK") {
434	$_[0]->unshift_read_line (sub {	1182	$_[0]->unshift_read (line => sub {
435	my $response = $_[1];	1183	my $response = $_[1];
436	...	1184	...
437	});	1185	});
438	}	1186	}
439	});	1187	});
440		1188
441	# request two	1189	# request two, simply returns 64 octets
442	$handle->push_write ("request 2\015\012");	1190	$handle->push_write ("request 2\015\012");
443		1191
444	# simply read 64 bytes, always	1192	# simply read 64 bytes, always
445	$handle->push_read_chunk (64, sub {	1193	$handle->push_read (chunk => 64, sub {
446	my $response = $_[1];	1194	my $response = $_[1];
447	...	1195	...
448	});	1196	});
449		1197
450	=over 4	1198	=over 4
451		1199
452	=cut	1200	=cut
453		1201
454	sub _drain_rbuf {	1202	sub _drain_rbuf {
455	my ($self) = @_;	1203	my ($self) = @_;
		1204
		1205	# avoid recursion
		1206	return if $self->{_skip_drain_rbuf};
		1207	local $self->{_skip_drain_rbuf} = 1;
		1208
		1209	while () {
		1210	# we need to use a separate tls read buffer, as we must not receive data while
		1211	# we are draining the buffer, and this can only happen with TLS.
		1212	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1213	if exists $self->{_tls_rbuf};
		1214
		1215	my $len = length $self->{rbuf};
		1216
		1217	if (my $cb = shift @{ $self->{_queue} }) {
		1218	unless ($cb->($self)) {
		1219	# no progress can be made
		1220	# (not enough data and no data forthcoming)
		1221	$self->_error (Errno::EPIPE, 1), return
		1222	if $self->{_eof};
		1223
		1224	unshift @{ $self->{_queue} }, $cb;
		1225	last;
		1226	}
		1227	} elsif ($self->{on_read}) {
		1228	last unless $len;
		1229
		1230	$self->{on_read}($self);
		1231
		1232	if (
		1233	$len == length $self->{rbuf} # if no data has been consumed
		1234	&& !@{ $self->{_queue} } # and the queue is still empty
		1235	&& $self->{on_read} # but we still have on_read
		1236	) {
		1237	# no further data will arrive
		1238	# so no progress can be made
		1239	$self->_error (Errno::EPIPE, 1), return
		1240	if $self->{_eof};
		1241
		1242	last; # more data might arrive
		1243	}
		1244	} else {
		1245	# read side becomes idle
		1246	delete $self->{_rw} unless $self->{tls};
		1247	last;
		1248	}
		1249	}
		1250
		1251	if ($self->{_eof}) {
		1252	$self->{on_eof}
		1253	? $self->{on_eof}($self)
		1254	: $self->_error (0, 1, "Unexpected end-of-file");
		1255
		1256	return;
		1257	}
456		1258
457	if (	1259	if (
458	defined $self->{rbuf_max}	1260	defined $self->{rbuf_max}
459	&& $self->{rbuf_max} < length $self->{rbuf}	1261	&& $self->{rbuf_max} < length $self->{rbuf}
460	) {	1262	) {
461	$! = &Errno::ENOSPC; return $self->error;	1263	$self->_error (Errno::ENOSPC, 1), return;
462	}	1264	}
463		1265
464	return if $self->{in_drain};	1266	# may need to restart read watcher
465	local $self->{in_drain} = 1;	1267	unless ($self->{_rw}) {
466		1268	$self->start_read
467	while (my $len = length $self->{rbuf}) {	1269	if $self->{on_read} || @{ $self->{_queue} };
468	no strict 'refs';
469	if (my $cb = shift @{ $self->{queue} }) {
470	unless ($cb->($self)) {
471	if ($self->{eof}) {
472	# no progress can be made (not enough data and no data forthcoming)
473	$! = &Errno::EPIPE; return $self->error;
474	}
475
476	unshift @{ $self->{queue} }, $cb;
477	return;
478	}
479	} elsif ($self->{on_read}) {
480	$self->{on_read}($self);
481
482	if (
483	$self->{eof} # if no further data will arrive
484	&& $len == length $self->{rbuf} # and no data has been consumed
485	&& !@{ $self->{queue} } # and the queue is still empty
486	&& $self->{on_read} # and we still want to read data
487	) {
488	# then no progress can be made
489	$! = &Errno::EPIPE; return $self->error;
490	}
491	} else {
492	# read side becomes idle
493	delete $self->{rw};
494	return;
495	}
496	}
497
498	if ($self->{eof}) {
499	$self->_shutdown;
500	$self->{on_eof}($self)
501	if $self->{on_eof};
502	}	1270	}
503	}	1271	}
504		1272
505	=item $handle->on_read ($cb)	1273	=item $handle->on_read ($cb)
506		1274
507	This replaces the currently set C<on_read> callback, or clears it (when	1275	This replaces the currently set C<on_read> callback, or clears it (when
508	the new callback is C<undef>). See the description of C<on_read> in the	1276	the new callback is C<undef>). See the description of C<on_read> in the
509	constructor.	1277	constructor.
510		1278
		1279	This method may invoke callbacks (and therefore the handle might be
		1280	destroyed after it returns).
		1281
511	=cut	1282	=cut
512		1283
513	sub on_read {	1284	sub on_read {
514	my ($self, $cb) = @_;	1285	my ($self, $cb) = @_;
515		1286
516	$self->{on_read} = $cb;	1287	$self->{on_read} = $cb;
		1288	$self->_drain_rbuf if $cb;
517	}	1289	}
518		1290
519	=item $handle->rbuf	1291	=item $handle->rbuf
520		1292
521	Returns the read buffer (as a modifiable lvalue).	1293	Returns the read buffer (as a modifiable lvalue). You can also access the
		1294	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1295	much faster, and no less clean).
522		1296
523	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1297	The only operation allowed on the read buffer (apart from looking at it)
524	you want.	1298	is removing data from its beginning. Otherwise modifying or appending to
		1299	it is not allowed and will lead to hard-to-track-down bugs.
525		1300
526	NOTE: The read buffer should only be used or modified if the C<on_read>,	1301	NOTE: The read buffer should only be used or modified in the C<on_read>
527	C<push_read> or C<unshift_read> methods are used. The other read methods	1302	callback or when C<push_read> or C<unshift_read> are used with a single
528	automatically manage the read buffer.	1303	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1304	will manage the read buffer on their own.
529		1305
530	=cut	1306	=cut
531		1307
532	sub rbuf : lvalue {	1308	sub rbuf : lvalue {
533	$_[0]{rbuf}	1309	$_[0]{rbuf}
…		…
550		1326
551	If enough data was available, then the callback must remove all data it is	1327	If enough data was available, then the callback must remove all data it is
552	interested in (which can be none at all) and return a true value. After returning	1328	interested in (which can be none at all) and return a true value. After returning
553	true, it will be removed from the queue.	1329	true, it will be removed from the queue.
554		1330
		1331	These methods may invoke callbacks (and therefore the handle might be
		1332	destroyed after it returns).
		1333
555	=cut	1334	=cut
		1335
		1336	our %RH;
		1337
		1338	sub register_read_type($$) {
		1339	$RH{$_[0]} = $_[1];
		1340	}
556		1341
557	sub push_read {	1342	sub push_read {
558	my $self = shift;	1343	my $self = shift;
559	my $cb = pop;	1344	my $cb = pop;
560		1345
561	if (@_) {	1346	if (@_) {
562	my $type = shift;	1347	my $type = shift;
563		1348
		1349	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
564	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	1350	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
565	->($self, $cb, @_);	1351	->($self, $cb, @_);
566	}	1352	}
567		1353
568	push @{ $self->{queue} }, $cb;	1354	push @{ $self->{_queue} }, $cb;
569	$self->_drain_rbuf;	1355	$self->_drain_rbuf;
570	}	1356	}
571		1357
572	sub unshift_read {	1358	sub unshift_read {
573	my $self = shift;	1359	my $self = shift;
574	my $cb = pop;	1360	my $cb = pop;
575		1361
576	if (@_) {	1362	if (@_) {
577	my $type = shift;	1363	my $type = shift;
578		1364
		1365	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
579	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")	1366	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
580	->($self, $cb, @_);	1367	->($self, $cb, @_);
581	}	1368	}
582		1369
583
584	unshift @{ $self->{queue} }, $cb;	1370	unshift @{ $self->{_queue} }, $cb;
585	$self->_drain_rbuf;	1371	$self->_drain_rbuf;
586	}	1372	}
587		1373
588	=item $handle->push_read (type => @args, $cb)	1374	=item $handle->push_read (type => @args, $cb)
589		1375
590	=item $handle->unshift_read (type => @args, $cb)	1376	=item $handle->unshift_read (type => @args, $cb)
591		1377
592	Instead of providing a callback that parses the data itself you can chose	1378	Instead of providing a callback that parses the data itself you can chose
593	between a number of predefined parsing formats, for chunks of data, lines	1379	between a number of predefined parsing formats, for chunks of data, lines
594	etc.	1380	etc. You can also specify the (fully qualified) name of a package, in
		1381	which case AnyEvent tries to load the package and then expects to find the
		1382	C<anyevent_read_type> function inside (see "custom read types", below).
595		1383
596	The types currently supported are:	1384	Predefined types are (if you have ideas for additional types, feel free to
		1385	drop by and tell us):
597		1386
598	=over 4	1387	=over 4
599		1388
600	=item chunk => $octets, $cb->($self, $data)	1389	=item chunk => $octets, $cb->($handle, $data)
601		1390
602	Invoke the callback only once C<$octets> bytes have been read. Pass the	1391	Invoke the callback only once C<$octets> bytes have been read. Pass the
603	data read to the callback. The callback will never be called with less	1392	data read to the callback. The callback will never be called with less
604	data.	1393	data.
605		1394
…		…
619	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1408	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
620	1	1409	1
621	}	1410	}
622	};	1411	};
623		1412
624	# compatibility with older API
625	sub push_read_chunk {
626	$_[0]->push_read (chunk => $_[1], $_[2]);
627	}
628
629	sub unshift_read_chunk {
630	$_[0]->unshift_read (chunk => $_[1], $_[2]);
631	}
632
633	=item line => [$eol, ]$cb->($self, $line, $eol)	1413	=item line => [$eol, ]$cb->($handle, $line, $eol)
634		1414
635	The callback will be called only once a full line (including the end of	1415	The callback will be called only once a full line (including the end of
636	line marker, C<$eol>) has been read. This line (excluding the end of line	1416	line marker, C<$eol>) has been read. This line (excluding the end of line
637	marker) will be passed to the callback as second argument (C<$line>), and	1417	marker) will be passed to the callback as second argument (C<$line>), and
638	the end of line marker as the third argument (C<$eol>).	1418	the end of line marker as the third argument (C<$eol>).
…		…
652	=cut	1432	=cut
653		1433
654	register_read_type line => sub {	1434	register_read_type line => sub {
655	my ($self, $cb, $eol) = @_;	1435	my ($self, $cb, $eol) = @_;
656		1436
657	$eol = qr|(\015?\012)| if @_ < 3;	1437	if (@_ < 3) {
		1438	# this is more than twice as fast as the generic code below
		1439	sub {
		1440	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1441
		1442	$cb->($_[0], $1, $2);
		1443	1
		1444	}
		1445	} else {
658	$eol = quotemeta $eol unless ref $eol;	1446	$eol = quotemeta $eol unless ref $eol;
659	$eol = qr|^(.*?)($eol)|s;	1447	$eol = qr|^(.*?)($eol)|s;
		1448
		1449	sub {
		1450	$_[0]{rbuf} =~ s/$eol// or return;
		1451
		1452	$cb->($_[0], $1, $2);
		1453	1
		1454	}
		1455	}
		1456	};
		1457
		1458	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1459
		1460	Makes a regex match against the regex object C<$accept> and returns
		1461	everything up to and including the match.
		1462
		1463	Example: read a single line terminated by '\n'.
		1464
		1465	$handle->push_read (regex => qr<\n>, sub { ... });
		1466
		1467	If C<$reject> is given and not undef, then it determines when the data is
		1468	to be rejected: it is matched against the data when the C<$accept> regex
		1469	does not match and generates an C<EBADMSG> error when it matches. This is
		1470	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1471	receive buffer overflow).
		1472
		1473	Example: expect a single decimal number followed by whitespace, reject
		1474	anything else (not the use of an anchor).
		1475
		1476	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1477
		1478	If C<$skip> is given and not C<undef>, then it will be matched against
		1479	the receive buffer when neither C<$accept> nor C<$reject> match,
		1480	and everything preceding and including the match will be accepted
		1481	unconditionally. This is useful to skip large amounts of data that you
		1482	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1483	have to start matching from the beginning. This is purely an optimisation
		1484	and is usually worth it only when you expect more than a few kilobytes.
		1485
		1486	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1487	expect the header to be very large (it isn't in practice, but...), we use
		1488	a skip regex to skip initial portions. The skip regex is tricky in that
		1489	it only accepts something not ending in either \015 or \012, as these are
		1490	required for the accept regex.
		1491
		1492	$handle->push_read (regex =>
		1493	qr<\015\012\015\012>,
		1494	undef, # no reject
		1495	qr<^.*[^\015\012]>,
		1496	sub { ... });
		1497
		1498	=cut
		1499
		1500	register_read_type regex => sub {
		1501	my ($self, $cb, $accept, $reject, $skip) = @_;
		1502
		1503	my $data;
		1504	my $rbuf = \$self->{rbuf};
660		1505
661	sub {	1506	sub {
662	$_[0]{rbuf} =~ s/$eol// or return;	1507	# accept
663		1508	if ($$rbuf =~ $accept) {
664	$cb->($_[0], $1, $2);	1509	$data .= substr $$rbuf, 0, $+[0], "";
		1510	$cb->($self, $data);
		1511	return 1;
		1512	}
665	1	1513
		1514	# reject
		1515	if ($reject && $$rbuf =~ $reject) {
		1516	$self->_error (Errno::EBADMSG);
		1517	}
		1518
		1519	# skip
		1520	if ($skip && $$rbuf =~ $skip) {
		1521	$data .= substr $$rbuf, 0, $+[0], "";
		1522	}
		1523
		1524	()
666	}	1525	}
667	};	1526	};
668		1527
669	# compatibility with older API
670	sub push_read_line {
671	my $self = shift;
672	$self->push_read (line => @_);
673	}
674
675	sub unshift_read_line {
676	my $self = shift;
677	$self->unshift_read (line => @_);
678	}
679
680	=item netstring => $cb->($string)	1528	=item netstring => $cb->($handle, $string)
681		1529
682	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).	1530	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
683		1531
684	Throws an error with C<$!> set to EBADMSG on format violations.	1532	Throws an error with C<$!> set to EBADMSG on format violations.
685		1533
…		…
689	my ($self, $cb) = @_;	1537	my ($self, $cb) = @_;
690		1538
691	sub {	1539	sub {
692	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {	1540	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
693	if ($_[0]{rbuf} =~ /[^0-9]/) {	1541	if ($_[0]{rbuf} =~ /[^0-9]/) {
694	$! = &Errno::EBADMSG;	1542	$self->_error (Errno::EBADMSG);
695	$self->error;
696	}	1543	}
697	return;	1544	return;
698	}	1545	}
699		1546
700	my $len = $1;	1547	my $len = $1;
…		…
703	my $string = $_[1];	1550	my $string = $_[1];
704	$_[0]->unshift_read (chunk => 1, sub {	1551	$_[0]->unshift_read (chunk => 1, sub {
705	if ($_[1] eq ",") {	1552	if ($_[1] eq ",") {
706	$cb->($_[0], $string);	1553	$cb->($_[0], $string);
707	} else {	1554	} else {
708	$! = &Errno::EBADMSG;
709	$self->error;	1555	$self->_error (Errno::EBADMSG);
710	}	1556	}
711	});	1557	});
712	});	1558	});
713		1559
714	1	1560	1
715	}	1561	}
716	};	1562	};
717		1563
		1564	=item packstring => $format, $cb->($handle, $string)
		1565
		1566	An octet string prefixed with an encoded length. The encoding C<$format>
		1567	uses the same format as a Perl C<pack> format, but must specify a single
		1568	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1569	optional C<!>, C<< < >> or C<< > >> modifier).
		1570
		1571	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1572	EPP uses a prefix of C<N> (4 octtes).
		1573
		1574	Example: read a block of data prefixed by its length in BER-encoded
		1575	format (very efficient).
		1576
		1577	$handle->push_read (packstring => "w", sub {
		1578	my ($handle, $data) = @_;
		1579	});
		1580
		1581	=cut
		1582
		1583	register_read_type packstring => sub {
		1584	my ($self, $cb, $format) = @_;
		1585
		1586	sub {
		1587	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1588	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1589	or return;
		1590
		1591	$format = length pack $format, $len;
		1592
		1593	# bypass unshift if we already have the remaining chunk
		1594	if ($format + $len <= length $_[0]{rbuf}) {
		1595	my $data = substr $_[0]{rbuf}, $format, $len;
		1596	substr $_[0]{rbuf}, 0, $format + $len, "";
		1597	$cb->($_[0], $data);
		1598	} else {
		1599	# remove prefix
		1600	substr $_[0]{rbuf}, 0, $format, "";
		1601
		1602	# read remaining chunk
		1603	$_[0]->unshift_read (chunk => $len, $cb);
		1604	}
		1605
		1606	1
		1607	}
		1608	};
		1609
		1610	=item json => $cb->($handle, $hash_or_arrayref)
		1611
		1612	Reads a JSON object or array, decodes it and passes it to the
		1613	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1614
		1615	If a C<json> object was passed to the constructor, then that will be used
		1616	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1617
		1618	This read type uses the incremental parser available with JSON version
		1619	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1620	dependency on your own: this module will load the JSON module, but
		1621	AnyEvent does not depend on it itself.
		1622
		1623	Since JSON texts are fully self-delimiting, the C<json> read and write
		1624	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1625	the C<json> write type description, above, for an actual example.
		1626
		1627	=cut
		1628
		1629	register_read_type json => sub {
		1630	my ($self, $cb) = @_;
		1631
		1632	my $json = $self->{json} ||= json_coder;
		1633
		1634	my $data;
		1635	my $rbuf = \$self->{rbuf};
		1636
		1637	sub {
		1638	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1639
		1640	if ($ref) {
		1641	$self->{rbuf} = $json->incr_text;
		1642	$json->incr_text = "";
		1643	$cb->($self, $ref);
		1644
		1645	1
		1646	} elsif ($@) {
		1647	# error case
		1648	$json->incr_skip;
		1649
		1650	$self->{rbuf} = $json->incr_text;
		1651	$json->incr_text = "";
		1652
		1653	$self->_error (Errno::EBADMSG);
		1654
		1655	()
		1656	} else {
		1657	$self->{rbuf} = "";
		1658
		1659	()
		1660	}
		1661	}
		1662	};
		1663
		1664	=item storable => $cb->($handle, $ref)
		1665
		1666	Deserialises a L<Storable> frozen representation as written by the
		1667	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1668	data).
		1669
		1670	Raises C<EBADMSG> error if the data could not be decoded.
		1671
		1672	=cut
		1673
		1674	register_read_type storable => sub {
		1675	my ($self, $cb) = @_;
		1676
		1677	require Storable;
		1678
		1679	sub {
		1680	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1681	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1682	or return;
		1683
		1684	my $format = length pack "w", $len;
		1685
		1686	# bypass unshift if we already have the remaining chunk
		1687	if ($format + $len <= length $_[0]{rbuf}) {
		1688	my $data = substr $_[0]{rbuf}, $format, $len;
		1689	substr $_[0]{rbuf}, 0, $format + $len, "";
		1690	$cb->($_[0], Storable::thaw ($data));
		1691	} else {
		1692	# remove prefix
		1693	substr $_[0]{rbuf}, 0, $format, "";
		1694
		1695	# read remaining chunk
		1696	$_[0]->unshift_read (chunk => $len, sub {
		1697	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1698	$cb->($_[0], $ref);
		1699	} else {
		1700	$self->_error (Errno::EBADMSG);
		1701	}
		1702	});
		1703	}
		1704
		1705	1
		1706	}
		1707	};
		1708
718	=back	1709	=back
719		1710
		1711	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
		1712
		1713	Instead of one of the predefined types, you can also specify the name
		1714	of a package. AnyEvent will try to load the package and then expects to
		1715	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1716	progressively tries to load the parent package until it either finds the
		1717	function (good) or runs out of packages (bad).
		1718
		1719	Whenever this type is used, C<push_read> will invoke the function with the
		1720	handle object, the original callback and the remaining arguments.
		1721
		1722	The function is supposed to return a callback (usually a closure) that
		1723	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1724	mentally treat the function as a "configurable read type to read callback"
		1725	converter.
		1726
		1727	It should invoke the original callback when it is done reading (remember
		1728	to pass C<$handle> as first argument as all other callbacks do that,
		1729	although there is no strict requirement on this).
		1730
		1731	For examples, see the source of this module (F<perldoc -m
		1732	AnyEvent::Handle>, search for C<register_read_type>)).
		1733
720	=item $handle->stop_read	1734	=item $handle->stop_read
721		1735
722	=item $handle->start_read	1736	=item $handle->start_read
723		1737
724	In rare cases you actually do not want to read anything from the	1738	In rare cases you actually do not want to read anything from the
725	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1739	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
726	any queued callbacks will be executed then. To start reading again, call	1740	any queued callbacks will be executed then. To start reading again, call
727	C<start_read>.	1741	C<start_read>.
728		1742
		1743	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1744	you change the C<on_read> callback or push/unshift a read callback, and it
		1745	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1746	there are any read requests in the queue.
		1747
		1748	These methods will have no effect when in TLS mode (as TLS doesn't support
		1749	half-duplex connections).
		1750
729	=cut	1751	=cut
730		1752
731	sub stop_read {	1753	sub stop_read {
732	my ($self) = @_;	1754	my ($self) = @_;
733		1755
734	delete $self->{rw};	1756	delete $self->{_rw} unless $self->{tls};
735	}	1757	}
736		1758
737	sub start_read {	1759	sub start_read {
738	my ($self) = @_;	1760	my ($self) = @_;
739		1761
740	unless ($self->{rw} || $self->{eof}) {	1762	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
741	Scalar::Util::weaken $self;	1763	Scalar::Util::weaken $self;
742		1764
743	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1765	$self->{_rw} = AE::io $self->{fh}, 0, sub {
744	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1766	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
745	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1767	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
746		1768
747	if ($len > 0) {	1769	if ($len > 0) {
748	$self->{filter_r}	1770	$self->{_activity} = $self->{_ractivity} = AE::now;
749	? $self->{filter_r}->($self, $rbuf)	1771
		1772	if ($self->{tls}) {
		1773	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1774
		1775	&_dotls ($self);
		1776	} else {
750	: $self->_drain_rbuf;	1777	$self->_drain_rbuf;
		1778	}
		1779
		1780	if ($len == $self->{read_size}) {
		1781	$self->{read_size} *= 2;
		1782	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		1783	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		1784	}
751		1785
752	} elsif (defined $len) {	1786	} elsif (defined $len) {
753	delete $self->{rw};	1787	delete $self->{_rw};
754	$self->{eof} = 1;	1788	$self->{_eof} = 1;
755	$self->_drain_rbuf;	1789	$self->_drain_rbuf;
756		1790
757	} elsif ($! != EAGAIN && $! != EINTR) {	1791	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
758	return $self->error;	1792	return $self->_error ($!, 1);
759	}	1793	}
760	});	1794	};
761	}	1795	}
762	}	1796	}
763		1797
		1798	our $ERROR_SYSCALL;
		1799	our $ERROR_WANT_READ;
		1800
		1801	sub _tls_error {
		1802	my ($self, $err) = @_;
		1803
		1804	return $self->_error ($!, 1)
		1805	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1806
		1807	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1808
		1809	# reduce error string to look less scary
		1810	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1811
		1812	if ($self->{_on_starttls}) {
		1813	(delete $self->{_on_starttls})->($self, undef, $err);
		1814	&_freetls;
		1815	} else {
		1816	&_freetls;
		1817	$self->_error (Errno::EPROTO, 1, $err);
		1818	}
		1819	}
		1820
		1821	# poll the write BIO and send the data if applicable
		1822	# also decode read data if possible
		1823	# this is basiclaly our TLS state machine
		1824	# more efficient implementations are possible with openssl,
		1825	# but not with the buggy and incomplete Net::SSLeay.
764	sub _dotls {	1826	sub _dotls {
765	my ($self) = @_;	1827	my ($self) = @_;
766		1828
		1829	my $tmp;
		1830
767	if (length $self->{tls_wbuf}) {	1831	if (length $self->{_tls_wbuf}) {
768	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{tls_wbuf})) > 0) {	1832	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
769	substr $self->{tls_wbuf}, 0, $len, "";	1833	substr $self->{_tls_wbuf}, 0, $tmp, "";
770	}	1834	}
771	}
772		1835
		1836	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1837	return $self->_tls_error ($tmp)
		1838	if $tmp != $ERROR_WANT_READ
		1839	&& ($tmp != $ERROR_SYSCALL || $!);
		1840	}
		1841
773	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{tls_wbio}))) {	1842	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1843	unless (length $tmp) {
		1844	$self->{_on_starttls}
		1845	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1846	&_freetls;
		1847
		1848	if ($self->{on_stoptls}) {
		1849	$self->{on_stoptls}($self);
		1850	return;
		1851	} else {
		1852	# let's treat SSL-eof as we treat normal EOF
		1853	delete $self->{_rw};
		1854	$self->{_eof} = 1;
		1855	}
		1856	}
		1857
		1858	$self->{_tls_rbuf} .= $tmp;
		1859	$self->_drain_rbuf;
		1860	$self->{tls} or return; # tls session might have gone away in callback
		1861	}
		1862
		1863	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1864	return $self->_tls_error ($tmp)
		1865	if $tmp != $ERROR_WANT_READ
		1866	&& ($tmp != $ERROR_SYSCALL || $!);
		1867
		1868	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
774	$self->{wbuf} .= $buf;	1869	$self->{wbuf} .= $tmp;
775	$self->_drain_wbuf;	1870	$self->_drain_wbuf;
		1871	$self->{tls} or return; # tls session might have gone away in callback
776	}	1872	}
777		1873
778	while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {	1874	$self->{_on_starttls}
779	$self->{rbuf} .= $buf;	1875	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
780	$self->_drain_rbuf;	1876	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
781	}
782
783	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
784
785	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
786	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
787	$self->error;
788	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
789	$! = &Errno::EIO;
790	$self->error;
791	}
792
793	# all others are fine for our purposes
794	}
795	}	1877	}
796		1878
797	=item $handle->starttls ($tls[, $tls_ctx])	1879	=item $handle->starttls ($tls[, $tls_ctx])
798		1880
799	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1881	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
800	object is created, you can also do that at a later time by calling	1882	object is created, you can also do that at a later time by calling
801	C<starttls>.	1883	C<starttls>.
802		1884
		1885	Starting TLS is currently an asynchronous operation - when you push some
		1886	write data and then call C<< ->starttls >> then TLS negotiation will start
		1887	immediately, after which the queued write data is then sent.
		1888
803	The first argument is the same as the C<tls> constructor argument (either	1889	The first argument is the same as the C<tls> constructor argument (either
804	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1890	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
805		1891
806	The second argument is the optional C<Net::SSLeay::CTX> object that is	1892	The second argument is the optional C<AnyEvent::TLS> object that is used
807	used when AnyEvent::Handle has to create its own TLS connection object.	1893	when AnyEvent::Handle has to create its own TLS connection object, or
		1894	a hash reference with C<< key => value >> pairs that will be used to
		1895	construct a new context.
808		1896
809	=cut	1897	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1898	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1899	changed to your liking. Note that the handshake might have already started
		1900	when this function returns.
810		1901
811	# TODO: maybe document...	1902	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1903	handshakes on the same stream. It is best to not attempt to use the
		1904	stream after stopping TLS.
		1905
		1906	This method may invoke callbacks (and therefore the handle might be
		1907	destroyed after it returns).
		1908
		1909	=cut
		1910
		1911	our %TLS_CACHE; #TODO not yet documented, should we?
		1912
812	sub starttls {	1913	sub starttls {
813	my ($self, $ssl, $ctx) = @_;	1914	my ($self, $tls, $ctx) = @_;
814		1915
815	$self->stoptls;	1916	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1917	if $self->{tls};
816		1918
817	if ($ssl eq "accept") {	1919	$self->{tls} = $tls;
818	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1920	$self->{tls_ctx} = $ctx if @_ > 2;
819	Net::SSLeay::set_accept_state ($ssl);	1921
820	} elsif ($ssl eq "connect") {	1922	return unless $self->{fh};
821	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1923
822	Net::SSLeay::set_connect_state ($ssl);	1924	require Net::SSLeay;
		1925
		1926	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1927	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1928
		1929	$tls = delete $self->{tls};
		1930	$ctx = $self->{tls_ctx};
		1931
		1932	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1933
		1934	if ("HASH" eq ref $ctx) {
		1935	require AnyEvent::TLS;
		1936
		1937	if ($ctx->{cache}) {
		1938	my $key = $ctx+0;
		1939	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1940	} else {
		1941	$ctx = new AnyEvent::TLS %$ctx;
		1942	}
		1943	}
823	}	1944
824		1945	$self->{tls_ctx} = $ctx || TLS_CTX ();
825	$self->{tls} = $ssl;	1946	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
826		1947
827	# basically, this is deep magic (because SSL_read should have the same issues)	1948	# basically, this is deep magic (because SSL_read should have the same issues)
828	# but the openssl maintainers basically said: "trust us, it just works".	1949	# but the openssl maintainers basically said: "trust us, it just works".
829	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1950	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
830	# and mismaintained ssleay-module doesn't even offer them).	1951	# and mismaintained ssleay-module doesn't even offer them).
831	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1952	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1953	#
		1954	# in short: this is a mess.
		1955	#
		1956	# note that we do not try to keep the length constant between writes as we are required to do.
		1957	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1958	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1959	# have identity issues in that area.
832	Net::SSLeay::CTX_set_mode ($self->{tls},	1960	# Net::SSLeay::CTX_set_mode ($ssl,
833	(eval { Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	1961	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
834	| (eval { Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	1962	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1963	Net::SSLeay::CTX_set_mode ($tls, 1|2);
835		1964
836	$self->{tls_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1965	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
837	$self->{tls_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1966	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
838		1967
		1968	Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf});
		1969
839	Net::SSLeay::set_bio ($ssl, $self->{tls_rbio}, $self->{tls_wbio});	1970	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
840		1971
841	$self->{filter_w} = sub {	1972	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
842	$_[0]{tls_wbuf} .= ${$_[1]};	1973	if $self->{on_starttls};
843	&_dotls;	1974
844	};	1975	&_dotls; # need to trigger the initial handshake
845	$self->{filter_r} = sub {	1976	$self->start_read; # make sure we actually do read
846	Net::SSLeay::BIO_write ($_[0]{tls_rbio}, ${$_[1]});
847	&_dotls;
848	};
849	}	1977	}
850		1978
851	=item $handle->stoptls	1979	=item $handle->stoptls
852		1980
853	Destroys the SSL connection, if any. Partial read or write data will be	1981	Shuts down the SSL connection - this makes a proper EOF handshake by
854	lost.	1982	sending a close notify to the other side, but since OpenSSL doesn't
		1983	support non-blocking shut downs, it is not guaranteed that you can re-use
		1984	the stream afterwards.
		1985
		1986	This method may invoke callbacks (and therefore the handle might be
		1987	destroyed after it returns).
855		1988
856	=cut	1989	=cut
857		1990
858	sub stoptls {	1991	sub stoptls {
859	my ($self) = @_;	1992	my ($self) = @_;
860		1993
861	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	1994	if ($self->{tls} && $self->{fh}) {
862	delete $self->{tls_rbio};	1995	Net::SSLeay::shutdown ($self->{tls});
863	delete $self->{tls_wbio};	1996
864	delete $self->{tls_wbuf};	1997	&_dotls;
865	delete $self->{filter_r};	1998
866	delete $self->{filter_w};	1999	# # we don't give a shit. no, we do, but we can't. no...#d#
		2000	# # we, we... have to use openssl :/#d#
		2001	# &_freetls;#d#
		2002	}
		2003	}
		2004
		2005	sub _freetls {
		2006	my ($self) = @_;
		2007
		2008	return unless $self->{tls};
		2009
		2010	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2011	if $self->{tls} > 0;
		2012
		2013	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
867	}	2014	}
868		2015
869	sub DESTROY {	2016	sub DESTROY {
870	my $self = shift;	2017	my ($self) = @_;
871		2018
872	$self->stoptls;	2019	&_freetls;
		2020
		2021	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		2022
		2023	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2024	my $fh = delete $self->{fh};
		2025	my $wbuf = delete $self->{wbuf};
		2026
		2027	my @linger;
		2028
		2029	push @linger, AE::io $fh, 1, sub {
		2030	my $len = syswrite $fh, $wbuf, length $wbuf;
		2031
		2032	if ($len > 0) {
		2033	substr $wbuf, 0, $len, "";
		2034	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
		2035	@linger = (); # end
		2036	}
		2037	};
		2038	push @linger, AE::timer $linger, 0, sub {
		2039	@linger = ();
		2040	};
		2041	}
873	}	2042	}
		2043
		2044	=item $handle->destroy
		2045
		2046	Shuts down the handle object as much as possible - this call ensures that
		2047	no further callbacks will be invoked and as many resources as possible
		2048	will be freed. Any method you will call on the handle object after
		2049	destroying it in this way will be silently ignored (and it will return the
		2050	empty list).
		2051
		2052	Normally, you can just "forget" any references to an AnyEvent::Handle
		2053	object and it will simply shut down. This works in fatal error and EOF
		2054	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2055	callback, so when you want to destroy the AnyEvent::Handle object from
		2056	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2057	that case.
		2058
		2059	Destroying the handle object in this way has the advantage that callbacks
		2060	will be removed as well, so if those are the only reference holders (as
		2061	is common), then one doesn't need to do anything special to break any
		2062	reference cycles.
		2063
		2064	The handle might still linger in the background and write out remaining
		2065	data, as specified by the C<linger> option, however.
		2066
		2067	=cut
		2068
		2069	sub destroy {
		2070	my ($self) = @_;
		2071
		2072	$self->DESTROY;
		2073	%$self = ();
		2074	bless $self, "AnyEvent::Handle::destroyed";
		2075	}
		2076
		2077	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2078	#nop
		2079	}
		2080
		2081	=item $handle->destroyed
		2082
		2083	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2084	->destroy >>, true otherwise.
		2085
		2086	Can be useful to decide whether the handle is still valid after some
		2087	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2088	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2089	can destroy the handle, so work can be avoided by checking sometimes:
		2090
		2091	$hdl->starttls ("accept");
		2092	return if $hdl->destroyed;
		2093	$hdl->push_write (...
		2094
		2095	Note that the call to C<push_write> will silently be ignored if the handle
		2096	has been destroyed, so often you can just ignore the possibility of the
		2097	handle being destroyed.
		2098
		2099	=cut
		2100
		2101	sub destroyed { 0 }
		2102	sub AnyEvent::Handle::destroyed::destroyed { 1 }
874		2103
875	=item AnyEvent::Handle::TLS_CTX	2104	=item AnyEvent::Handle::TLS_CTX
876		2105
877	This function creates and returns the Net::SSLeay::CTX object used by	2106	This function creates and returns the AnyEvent::TLS object used by default
878	default for TLS mode.	2107	for TLS mode.
879		2108
880	The context is created like this:	2109	The context is created by calling L<AnyEvent::TLS> without any arguments.
881
882	Net::SSLeay::load_error_strings;
883	Net::SSLeay::SSLeay_add_ssl_algorithms;
884	Net::SSLeay::randomize;
885
886	my $CTX = Net::SSLeay::CTX_new;
887
888	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
889		2110
890	=cut	2111	=cut
891		2112
892	our $TLS_CTX;	2113	our $TLS_CTX;
893		2114
894	sub TLS_CTX() {	2115	sub TLS_CTX() {
895	$TLS_CTX || do {	2116	$TLS_CTX ||= do {
896	require Net::SSLeay;	2117	require AnyEvent::TLS;
897		2118
898	Net::SSLeay::load_error_strings ();	2119	new AnyEvent::TLS
899	Net::SSLeay::SSLeay_add_ssl_algorithms ();
900	Net::SSLeay::randomize ();
901
902	$TLS_CTX = Net::SSLeay::CTX_new ();
903
904	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
905
906	$TLS_CTX
907	}	2120	}
908	}	2121	}
909		2122
910	=back	2123	=back
911		2124
		2125
		2126	=head1 NONFREQUENTLY ASKED QUESTIONS
		2127
		2128	=over 4
		2129
		2130	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2131	still get further invocations!
		2132
		2133	That's because AnyEvent::Handle keeps a reference to itself when handling
		2134	read or write callbacks.
		2135
		2136	It is only safe to "forget" the reference inside EOF or error callbacks,
		2137	from within all other callbacks, you need to explicitly call the C<<
		2138	->destroy >> method.
		2139
		2140	=item Why is my C<on_eof> callback never called?
		2141
		2142	Probably because your C<on_error> callback is being called instead: When
		2143	you have outstanding requests in your read queue, then an EOF is
		2144	considered an error as you clearly expected some data.
		2145
		2146	To avoid this, make sure you have an empty read queue whenever your handle
		2147	is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
		2148	an C<on_read> handler that simply pushes the first read requests in the
		2149	queue.
		2150
		2151	See also the next question, which explains this in a bit more detail.
		2152
		2153	=item How can I serve requests in a loop?
		2154
		2155	Most protocols consist of some setup phase (authentication for example)
		2156	followed by a request handling phase, where the server waits for requests
		2157	and handles them, in a loop.
		2158
		2159	There are two important variants: The first (traditional, better) variant
		2160	handles requests until the server gets some QUIT command, causing it to
		2161	close the connection first (highly desirable for a busy TCP server). A
		2162	client dropping the connection is an error, which means this variant can
		2163	detect an unexpected detection close.
		2164
		2165	To handle this case, always make sure you have a on-empty read queue, by
		2166	pushing the "read request start" handler on it:
		2167
		2168	# we assume a request starts with a single line
		2169	my @start_request; @start_request = (line => sub {
		2170	my ($hdl, $line) = @_;
		2171
		2172	... handle request
		2173
		2174	# push next request read, possibly from a nested callback
		2175	$hdl->push_read (@start_request);
		2176	});
		2177
		2178	# auth done, now go into request handling loop
		2179	# now push the first @start_request
		2180	$hdl->push_read (@start_request);
		2181
		2182	By always having an outstanding C<push_read>, the handle always expects
		2183	some data and raises the C<EPIPE> error when the connction is dropped
		2184	unexpectedly.
		2185
		2186	The second variant is a protocol where the client can drop the connection
		2187	at any time. For TCP, this means that the server machine may run out of
		2188	sockets easier, and in general, it means you cnanot distinguish a protocl
		2189	failure/client crash from a normal connection close. Nevertheless, these
		2190	kinds of protocols are common (and sometimes even the best solution to the
		2191	problem).
		2192
		2193	Having an outstanding read request at all times is possible if you ignore
		2194	C<EPIPE> errors, but this doesn't help with when the client drops the
		2195	connection during a request, which would still be an error.
		2196
		2197	A better solution is to push the initial request read in an C<on_read>
		2198	callback. This avoids an error, as when the server doesn't expect data
		2199	(i.e. is idly waiting for the next request, an EOF will not raise an
		2200	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2201	and simpler:
		2202
		2203	# auth done, now go into request handling loop
		2204	$hdl->on_read (sub {
		2205	my ($hdl) = @_;
		2206
		2207	# called each time we receive data but the read queue is empty
		2208	# simply start read the request
		2209
		2210	$hdl->push_read (line => sub {
		2211	my ($hdl, $line) = @_;
		2212
		2213	... handle request
		2214
		2215	# do nothing special when the request has been handled, just
		2216	# let the request queue go empty.
		2217	});
		2218	});
		2219
		2220	=item I get different callback invocations in TLS mode/Why can't I pause
		2221	reading?
		2222
		2223	Unlike, say, TCP, TLS connections do not consist of two independent
		2224	communication channels, one for each direction. Or put differently, the
		2225	read and write directions are not independent of each other: you cannot
		2226	write data unless you are also prepared to read, and vice versa.
		2227
		2228	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2229	callback invocations when you are not expecting any read data - the reason
		2230	is that AnyEvent::Handle always reads in TLS mode.
		2231
		2232	During the connection, you have to make sure that you always have a
		2233	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2234	connection (or when you no longer want to use it) you can call the
		2235	C<destroy> method.
		2236
		2237	=item How do I read data until the other side closes the connection?
		2238
		2239	If you just want to read your data into a perl scalar, the easiest way
		2240	to achieve this is by setting an C<on_read> callback that does nothing,
		2241	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2242	will be in C<$_[0]{rbuf}>:
		2243
		2244	$handle->on_read (sub { });
		2245	$handle->on_eof (undef);
		2246	$handle->on_error (sub {
		2247	my $data = delete $_[0]{rbuf};
		2248	});
		2249
		2250	The reason to use C<on_error> is that TCP connections, due to latencies
		2251	and packets loss, might get closed quite violently with an error, when in
		2252	fact all data has been received.
		2253
		2254	It is usually better to use acknowledgements when transferring data,
		2255	to make sure the other side hasn't just died and you got the data
		2256	intact. This is also one reason why so many internet protocols have an
		2257	explicit QUIT command.
		2258
		2259	=item I don't want to destroy the handle too early - how do I wait until
		2260	all data has been written?
		2261
		2262	After writing your last bits of data, set the C<on_drain> callback
		2263	and destroy the handle in there - with the default setting of
		2264	C<low_water_mark> this will be called precisely when all data has been
		2265	written to the socket:
		2266
		2267	$handle->push_write (...);
		2268	$handle->on_drain (sub {
		2269	warn "all data submitted to the kernel\n";
		2270	undef $handle;
		2271	});
		2272
		2273	If you just want to queue some data and then signal EOF to the other side,
		2274	consider using C<< ->push_shutdown >> instead.
		2275
		2276	=item I want to contact a TLS/SSL server, I don't care about security.
		2277
		2278	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2279	connect to it and then create the AnyEvent::Handle with the C<tls>
		2280	parameter:
		2281
		2282	tcp_connect $host, $port, sub {
		2283	my ($fh) = @_;
		2284
		2285	my $handle = new AnyEvent::Handle
		2286	fh => $fh,
		2287	tls => "connect",
		2288	on_error => sub { ... };
		2289
		2290	$handle->push_write (...);
		2291	};
		2292
		2293	=item I want to contact a TLS/SSL server, I do care about security.
		2294
		2295	Then you should additionally enable certificate verification, including
		2296	peername verification, if the protocol you use supports it (see
		2297	L<AnyEvent::TLS>, C<verify_peername>).
		2298
		2299	E.g. for HTTPS:
		2300
		2301	tcp_connect $host, $port, sub {
		2302	my ($fh) = @_;
		2303
		2304	my $handle = new AnyEvent::Handle
		2305	fh => $fh,
		2306	peername => $host,
		2307	tls => "connect",
		2308	tls_ctx => { verify => 1, verify_peername => "https" },
		2309	...
		2310
		2311	Note that you must specify the hostname you connected to (or whatever
		2312	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2313	peername verification will be done.
		2314
		2315	The above will use the system-dependent default set of trusted CA
		2316	certificates. If you want to check against a specific CA, add the
		2317	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2318
		2319	tls_ctx => {
		2320	verify => 1,
		2321	verify_peername => "https",
		2322	ca_file => "my-ca-cert.pem",
		2323	},
		2324
		2325	=item I want to create a TLS/SSL server, how do I do that?
		2326
		2327	Well, you first need to get a server certificate and key. You have
		2328	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2329	self-signed certificate (cheap. check the search engine of your choice,
		2330	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2331	nice program for that purpose).
		2332
		2333	Then create a file with your private key (in PEM format, see
		2334	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2335	file should then look like this:
		2336
		2337	-----BEGIN RSA PRIVATE KEY-----
		2338	...header data
		2339	... lots of base64'y-stuff
		2340	-----END RSA PRIVATE KEY-----
		2341
		2342	-----BEGIN CERTIFICATE-----
		2343	... lots of base64'y-stuff
		2344	-----END CERTIFICATE-----
		2345
		2346	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2347	specify this file as C<cert_file>:
		2348
		2349	tcp_server undef, $port, sub {
		2350	my ($fh) = @_;
		2351
		2352	my $handle = new AnyEvent::Handle
		2353	fh => $fh,
		2354	tls => "accept",
		2355	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2356	...
		2357
		2358	When you have intermediate CA certificates that your clients might not
		2359	know about, just append them to the C<cert_file>.
		2360
		2361	=back
		2362
		2363
		2364	=head1 SUBCLASSING AnyEvent::Handle
		2365
		2366	In many cases, you might want to subclass AnyEvent::Handle.
		2367
		2368	To make this easier, a given version of AnyEvent::Handle uses these
		2369	conventions:
		2370
		2371	=over 4
		2372
		2373	=item * all constructor arguments become object members.
		2374
		2375	At least initially, when you pass a C<tls>-argument to the constructor it
		2376	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2377	mutated later on (for example C<tls> will hold the TLS connection object).
		2378
		2379	=item * other object member names are prefixed with an C<_>.
		2380
		2381	All object members not explicitly documented (internal use) are prefixed
		2382	with an underscore character, so the remaining non-C<_>-namespace is free
		2383	for use for subclasses.
		2384
		2385	=item * all members not documented here and not prefixed with an underscore
		2386	are free to use in subclasses.
		2387
		2388	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2389	member variables, but that's just life. At least it is documented.
		2390
		2391	=back
		2392
912	=head1 AUTHOR	2393	=head1 AUTHOR
913		2394
914	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	2395	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
915		2396
916	=cut	2397	=cut

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