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Revision 1.20 by elmex, Sat May 24 08:16:50 2008 UTC vs.
Revision 1.230 by root, Tue Mar 27 16:21:11 2012 UTC

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict;
5
6	use AnyEvent ();
7	use AnyEvent::Util ();
8	use Scalar::Util ();
9	use Carp ();
10	use Fcntl ();
11	use Errno qw/EAGAIN EINTR/;
12
13	=head1 NAME	1	=head1 NAME
14		2
15	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	3	AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
16
17	This module is experimental.
18
19	=cut
20
21	our $VERSION = '0.04';
22		4
23	=head1 SYNOPSIS	5	=head1 SYNOPSIS
24		6
25	use AnyEvent;	7	use AnyEvent;
26	use AnyEvent::Handle;	8	use AnyEvent::Handle;
27		9
28	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
29		11
30	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	12	my $hdl; $hdl = new AnyEvent::Handle
31
32	#TODO
33
34	# or use the constructor to pass the callback:
35
36	my $ae_fh2 =
37	AnyEvent::Handle->new (
38	fh => \*STDIN,	13	fh => \*STDIN,
39	on_eof => sub {	14	on_error => sub {
40	$cv->broadcast;	15	my ($hdl, $fatal, $msg) = @_;
41	},	16	AE::log error => "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, $line) = @_;
		27	say "got line <$line>";
		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 (you can access that
		120	file handle via C<< $handle->{fh} >>). It could be used to prepare the
		121	file handle with parameters required for the actual connect (as opposed to
		122	settings that can be changed when the connection is already established).
		123
		124	The return value of this callback should be the connect timeout value in
		125	seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
		126	default timeout is to be used).
		127
		128	=item on_connect => $cb->($handle, $host, $port, $retry->())
		129
		130	This callback is called when a connection has been successfully established.
		131
		132	The peer's numeric host and port (the socket peername) are passed as
		133	parameters, together with a retry callback. At the time it is called the
		134	read and write queues, EOF status, TLS status and similar properties of
		135	the handle will have been reset.
		136
		137	It is not allowed to use the read or write queues while the handle object
		138	is connecting.
		139
		140	If, for some reason, the handle is not acceptable, calling C<$retry> will
		141	continue with the next connection target (in case of multi-homed hosts or
		142	SRV records there can be multiple connection endpoints). The C<$retry>
		143	callback can be invoked after the connect callback returns, i.e. one can
		144	start a handshake and then decide to retry with the next host if the
		145	handshake fails.
		146
		147	In most cases, you should ignore the C<$retry> parameter.
		148
		149	=item on_connect_error => $cb->($handle, $message)
		150
		151	This callback is called when the connection could not be
		152	established. C<$!> will contain the relevant error code, and C<$message> a
		153	message describing it (usually the same as C<"$!">).
		154
		155	If this callback isn't specified, then C<on_error> will be called with a
		156	fatal error instead.
		157
		158	=back
		159
		160	=item on_error => $cb->($handle, $fatal, $message)
		161
87	This is the fatal error callback, that is called when, well, a fatal error	162	This is the error callback, which is called when, well, some error
88	occurs, such as not being able to resolve the hostname, failure to connect	163	occured, such as not being able to resolve the hostname, failure to
89	or a read error.	164	connect, or a read error.
90		165
91	The object will not be in a usable state when this callback has been	166	Some errors are fatal (which is indicated by C<$fatal> being true). On
92	called.	167	fatal errors the handle object will be destroyed (by a call to C<< ->
		168	destroy >>) after invoking the error callback (which means you are free to
		169	examine the handle object). Examples of fatal errors are an EOF condition
		170	with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
		171	cases where the other side can close the connection at will, it is
		172	often easiest to not report C<EPIPE> errors in this callback.
93		173
		174	AnyEvent::Handle tries to find an appropriate error code for you to check
		175	against, but in some cases (TLS errors), this does not work well. It is
		176	recommended to always output the C<$message> argument in human-readable
		177	error messages (it's usually the same as C<"$!">).
		178
		179	Non-fatal errors can be retried by returning, but it is recommended
		180	to simply ignore this parameter and instead abondon the handle object
		181	when this callback is invoked. Examples of non-fatal errors are timeouts
		182	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		183
94	On callback entrance, the value of C<$!> contains the operating system	184	On entry to the callback, the value of C<$!> contains the operating
95	error (or C<ENOSPC> or C<EPIPE>).	185	system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		186	C<EPROTO>).
96		187
97	While not mandatory, it is I<highly> recommended to set this callback, as	188	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	189	you will not be notified of errors otherwise. The default just calls
99	die.	190	C<croak>.
100		191
101	=item on_read => $cb->($self)	192	=item on_read => $cb->($handle)
102		193
103	This sets the default read callback, which is called when data arrives	194	This sets the default read callback, which is called when data arrives
104	and no read request is in the queue.	195	and no read request is in the queue (unlike read queue callbacks, this
		196	callback will only be called when at least one octet of data is in the
		197	read buffer).
105		198
106	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	199	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
107	method or access the C<$self->{rbuf}> member directly.	200	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		201	must not enlarge or modify the read buffer, you can only remove data at
		202	the beginning from it.
108		203
		204	You can also call C<< ->push_read (...) >> or any other function that
		205	modifies the read queue. Or do both. Or ...
		206
109	When an EOF condition is detected then AnyEvent::Handle will first try to	207	When an EOF condition is detected, AnyEvent::Handle will first try to
110	feed all the remaining data to the queued callbacks and C<on_read> before	208	feed all the remaining data to the queued callbacks and C<on_read> before
111	calling the C<on_eof> callback. If no progress can be made, then a fatal	209	calling the C<on_eof> callback. If no progress can be made, then a fatal
112	error will be raised (with C<$!> set to C<EPIPE>).	210	error will be raised (with C<$!> set to C<EPIPE>).
113		211
		212	Note that, unlike requests in the read queue, an C<on_read> callback
		213	doesn't mean you I<require> some data: if there is an EOF and there
		214	are outstanding read requests then an error will be flagged. With an
		215	C<on_read> callback, the C<on_eof> callback will be invoked.
		216
		217	=item on_eof => $cb->($handle)
		218
		219	Set the callback to be called when an end-of-file condition is detected,
		220	i.e. in the case of a socket, when the other side has closed the
		221	connection cleanly, and there are no outstanding read requests in the
		222	queue (if there are read requests, then an EOF counts as an unexpected
		223	connection close and will be flagged as an error).
		224
		225	For sockets, this just means that the other side has stopped sending data,
		226	you can still try to write data, and, in fact, one can return from the EOF
		227	callback and continue writing data, as only the read part has been shut
		228	down.
		229
		230	If an EOF condition has been detected but no C<on_eof> callback has been
		231	set, then a fatal error will be raised with C<$!> set to <0>.
		232
114	=item on_drain => $cb->()	233	=item on_drain => $cb->($handle)
115		234
116	This sets the callback that is called when the write buffer becomes empty	235	This sets the callback that is called once when the write buffer becomes
117	(or when the callback is set and the buffer is empty already).	236	empty (and immediately when the handle object is created).
118		237
119	To append to the write buffer, use the C<< ->push_write >> method.	238	To append to the write buffer, use the C<< ->push_write >> method.
		239
		240	This callback is useful when you don't want to put all of your write data
		241	into the queue at once, for example, when you want to write the contents
		242	of some file to the socket you might not want to read the whole file into
		243	memory and push it into the queue, but instead only read more data from
		244	the file when the write queue becomes empty.
		245
		246	=item timeout => $fractional_seconds
		247
		248	=item rtimeout => $fractional_seconds
		249
		250	=item wtimeout => $fractional_seconds
		251
		252	If non-zero, then these enables an "inactivity" timeout: whenever this
		253	many seconds pass without a successful read or write on the underlying
		254	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
		255	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		256	error will be raised).
		257
		258	There are three variants of the timeouts that work independently of each
		259	other, for both read and write (triggered when nothing was read I<OR>
		260	written), just read (triggered when nothing was read), and just write:
		261	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		262	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		263	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		264
		265	Note that timeout processing is active even when you do not have any
		266	outstanding read or write requests: If you plan to keep the connection
		267	idle then you should disable the timeout temporarily or ignore the
		268	timeout in the corresponding C<on_timeout> callback, in which case
		269	AnyEvent::Handle will simply restart the timeout.
		270
		271	Zero (the default) disables the corresponding timeout.
		272
		273	=item on_timeout => $cb->($handle)
		274
		275	=item on_rtimeout => $cb->($handle)
		276
		277	=item on_wtimeout => $cb->($handle)
		278
		279	Called whenever the inactivity timeout passes. If you return from this
		280	callback, then the timeout will be reset as if some activity had happened,
		281	so this condition is not fatal in any way.
120		282
121	=item rbuf_max => <bytes>	283	=item rbuf_max => <bytes>
122		284
123	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	285	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
124	when the read buffer ever (strictly) exceeds this size. This is useful to	286	when the read buffer ever (strictly) exceeds this size. This is useful to
125	avoid denial-of-service attacks.	287	avoid some forms of denial-of-service attacks.
126		288
127	For example, a server accepting connections from untrusted sources should	289	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	290	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	291	(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	292	amount of data without a callback ever being called as long as the line
131	isn't finished).	293	isn't finished).
132		294
		295	=item wbuf_max => <bytes>
		296
		297	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		298	when the write buffer ever (strictly) exceeds this size. This is useful to
		299	avoid some forms of denial-of-service attacks.
		300
		301	Although the units of this parameter is bytes, this is the I<raw> number
		302	of bytes not yet accepted by the kernel. This can make a difference when
		303	you e.g. use TLS, as TLS typically makes your write data larger (but it
		304	can also make it smaller due to compression).
		305
		306	As an example of when this limit is useful, take a chat server that sends
		307	chat messages to a client. If the client does not read those in a timely
		308	manner then the send buffer in the server would grow unbounded.
		309
		310	=item autocork => <boolean>
		311
		312	When disabled (the default), C<push_write> will try to immediately
		313	write the data to the handle if possible. This avoids having to register
		314	a write watcher and wait for the next event loop iteration, but can
		315	be inefficient if you write multiple small chunks (on the wire, this
		316	disadvantage is usually avoided by your kernel's nagle algorithm, see
		317	C<no_delay>, but this option can save costly syscalls).
		318
		319	When enabled, writes will always be queued till the next event loop
		320	iteration. This is efficient when you do many small writes per iteration,
		321	but less efficient when you do a single write only per iteration (or when
		322	the write buffer often is full). It also increases write latency.
		323
		324	=item no_delay => <boolean>
		325
		326	When doing small writes on sockets, your operating system kernel might
		327	wait a bit for more data before actually sending it out. This is called
		328	the Nagle algorithm, and usually it is beneficial.
		329
		330	In some situations you want as low a delay as possible, which can be
		331	accomplishd by setting this option to a true value.
		332
		333	The default is your operating system's default behaviour (most likely
		334	enabled). This option explicitly enables or disables it, if possible.
		335
		336	=item keepalive => <boolean>
		337
		338	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		339	normally, TCP connections have no time-out once established, so TCP
		340	connections, once established, can stay alive forever even when the other
		341	side has long gone. TCP keepalives are a cheap way to take down long-lived
		342	TCP connections when the other side becomes unreachable. While the default
		343	is OS-dependent, TCP keepalives usually kick in after around two hours,
		344	and, if the other side doesn't reply, take down the TCP connection some 10
		345	to 15 minutes later.
		346
		347	It is harmless to specify this option for file handles that do not support
		348	keepalives, and enabling it on connections that are potentially long-lived
		349	is usually a good idea.
		350
		351	=item oobinline => <boolean>
		352
		353	BSD majorly fucked up the implementation of TCP urgent data. The result
		354	is that almost no OS implements TCP according to the specs, and every OS
		355	implements it slightly differently.
		356
		357	If you want to handle TCP urgent data, then setting this flag (the default
		358	is enabled) gives you the most portable way of getting urgent data, by
		359	putting it into the stream.
		360
		361	Since BSD emulation of OOB data on top of TCP's urgent data can have
		362	security implications, AnyEvent::Handle sets this flag automatically
		363	unless explicitly specified. Note that setting this flag after
		364	establishing a connection I<may> be a bit too late (data loss could
		365	already have occured on BSD systems), but at least it will protect you
		366	from most attacks.
		367
133	=item read_size => <bytes>	368	=item read_size => <bytes>
134		369
135	The default read block size (the amount of bytes this module will try to read	370	The initial read block size, the number of bytes this module will try
136	on each [loop iteration). Default: C<4096>.	371	to read during each loop iteration. Each handle object will consume
		372	at least this amount of memory for the read buffer as well, so when
		373	handling many connections watch out for memory requirements). See also
		374	C<max_read_size>. Default: C<2048>.
		375
		376	=item max_read_size => <bytes>
		377
		378	The maximum read buffer size used by the dynamic adjustment
		379	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		380	one go it will double C<read_size> up to the maximum given by this
		381	option. Default: C<131072> or C<read_size>, whichever is higher.
137		382
138	=item low_water_mark => <bytes>	383	=item low_water_mark => <bytes>
139		384
140	Sets the amount of bytes (default: C<0>) that make up an "empty" write	385	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	386	buffer: If the buffer reaches this size or gets even samller it is
142	considered empty.	387	considered empty.
143		388
		389	Sometimes it can be beneficial (for performance reasons) to add data to
		390	the write buffer before it is fully drained, but this is a rare case, as
		391	the operating system kernel usually buffers data as well, so the default
		392	is good in almost all cases.
		393
		394	=item linger => <seconds>
		395
		396	If this is non-zero (default: C<3600>), the destructor of the
		397	AnyEvent::Handle object will check whether there is still outstanding
		398	write data and will install a watcher that will write this data to the
		399	socket. No errors will be reported (this mostly matches how the operating
		400	system treats outstanding data at socket close time).
		401
		402	This will not work for partial TLS data that could not be encoded
		403	yet. This data will be lost. Calling the C<stoptls> method in time might
		404	help.
		405
		406	=item peername => $string
		407
		408	A string used to identify the remote site - usually the DNS hostname
		409	(I<not> IDN!) used to create the connection, rarely the IP address.
		410
		411	Apart from being useful in error messages, this string is also used in TLS
		412	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		413	verification will be skipped when C<peername> is not specified or is
		414	C<undef>.
		415
144	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	416	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
145		417
146	When this parameter is given, it enables TLS (SSL) mode, that means it	418	When this parameter is given, it enables TLS (SSL) mode, that means
147	will start making tls handshake and will transparently encrypt/decrypt	419	AnyEvent will start a TLS handshake as soon as the connection has been
148	data.	420	established and will transparently encrypt/decrypt data afterwards.
149		421
150	For the TLS server side, use C<accept>, and for the TLS client side of a	422	All TLS protocol errors will be signalled as C<EPROTO>, with an
151	connection, use C<connect> mode.	423	appropriate error message.
		424
		425	TLS mode requires Net::SSLeay to be installed (it will be loaded
		426	automatically when you try to create a TLS handle): this module doesn't
		427	have a dependency on that module, so if your module requires it, you have
		428	to add the dependency yourself.
		429
		430	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		431	C<accept>, and for the TLS client side of a connection, use C<connect>
		432	mode.
152		433
153	You can also provide your own TLS connection object, but you have	434	You can also provide your own TLS connection object, but you have
154	to make sure that you call either C<Net::SSLeay::set_connect_state>	435	to make sure that you call either C<Net::SSLeay::set_connect_state>
155	or C<Net::SSLeay::set_accept_state> on it before you pass it to	436	or C<Net::SSLeay::set_accept_state> on it before you pass it to
156	AnyEvent::Handle.	437	AnyEvent::Handle. Also, this module will take ownership of this connection
		438	object.
157		439
158	=item tls_ctx => $ssl_ctx	440	At some future point, AnyEvent::Handle might switch to another TLS
		441	implementation, then the option to use your own session object will go
		442	away.
159		443
		444	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		445	passing in the wrong integer will lead to certain crash. This most often
		446	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		447	segmentation fault.
		448
		449	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
		450
		451	=item tls_ctx => $anyevent_tls
		452
160	Use the given Net::SSLeay::CTX object to create the new TLS connection	453	Use the given C<AnyEvent::TLS> object to create the new TLS connection
161	(unless a connection object was specified directly). If this parameter is	454	(unless a connection object was specified directly). If this
162	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	455	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		456	C<AnyEvent::Handle::TLS_CTX>.
		457
		458	Instead of an object, you can also specify a hash reference with C<< key
		459	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		460	new TLS context object.
		461
		462	=item on_starttls => $cb->($handle, $success[, $error_message])
		463
		464	This callback will be invoked when the TLS/SSL handshake has finished. If
		465	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		466	(C<on_stoptls> will not be called in this case).
		467
		468	The session in C<< $handle->{tls} >> can still be examined in this
		469	callback, even when the handshake was not successful.
		470
		471	TLS handshake failures will not cause C<on_error> to be invoked when this
		472	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		473
		474	Without this callback, handshake failures lead to C<on_error> being
		475	called as usual.
		476
		477	Note that you cannot just call C<starttls> again in this callback. If you
		478	need to do that, start an zero-second timer instead whose callback can
		479	then call C<< ->starttls >> again.
		480
		481	=item on_stoptls => $cb->($handle)
		482
		483	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		484	set, then it will be invoked after freeing the TLS session. If it is not,
		485	then a TLS shutdown condition will be treated like a normal EOF condition
		486	on the handle.
		487
		488	The session in C<< $handle->{tls} >> can still be examined in this
		489	callback.
		490
		491	This callback will only be called on TLS shutdowns, not when the
		492	underlying handle signals EOF.
		493
		494	=item json => JSON or JSON::XS object
		495
		496	This is the json coder object used by the C<json> read and write types.
		497
		498	If you don't supply it, then AnyEvent::Handle will create and use a
		499	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		500	texts.
		501
		502	Note that you are responsible to depend on the JSON module if you want to
		503	use this functionality, as AnyEvent does not have a dependency itself.
163		504
164	=back	505	=back
165		506
166	=cut	507	=cut
167		508
168	sub new {	509	sub new {
169	my $class = shift;	510	my $class = shift;
170
171	my $self = bless { @_ }, $class;	511	my $self = bless { @_ }, $class;
172		512
173	$self->{fh} or Carp::croak "mandatory argument fh is missing";	513	if ($self->{fh}) {
		514	$self->_start;
		515	return unless $self->{fh}; # could be gone by now
		516
		517	} elsif ($self->{connect}) {
		518	require AnyEvent::Socket;
		519
		520	$self->{peername} = $self->{connect}[0]
		521	unless exists $self->{peername};
		522
		523	$self->{_skip_drain_rbuf} = 1;
		524
		525	{
		526	Scalar::Util::weaken (my $self = $self);
		527
		528	$self->{_connect} =
		529	AnyEvent::Socket::tcp_connect (
		530	$self->{connect}[0],
		531	$self->{connect}[1],
		532	sub {
		533	my ($fh, $host, $port, $retry) = @_;
		534
		535	delete $self->{_connect}; # no longer needed
		536
		537	if ($fh) {
		538	$self->{fh} = $fh;
		539
		540	delete $self->{_skip_drain_rbuf};
		541	$self->_start;
		542
		543	$self->{on_connect}
		544	and $self->{on_connect}($self, $host, $port, sub {
		545	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		546	$self->{_skip_drain_rbuf} = 1;
		547	&$retry;
		548	});
		549
		550	} else {
		551	if ($self->{on_connect_error}) {
		552	$self->{on_connect_error}($self, "$!");
		553	$self->destroy if $self;
		554	} else {
		555	$self->_error ($!, 1);
		556	}
		557	}
		558	},
		559	sub {
		560	local $self->{fh} = $_[0];
		561
		562	$self->{on_prepare}
		563	? $self->{on_prepare}->($self)
		564	: ()
		565	}
		566	);
		567	}
		568
		569	} else {
		570	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		571	}
		572
		573	$self
		574	}
		575
		576	sub _start {
		577	my ($self) = @_;
		578
		579	# too many clueless people try to use udp and similar sockets
		580	# with AnyEvent::Handle, do them a favour.
		581	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		582	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		583	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
174		584
175	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	585	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
176		586
177	if ($self->{tls}) {	587	$self->{_activity} =
178	require Net::SSLeay;	588	$self->{_ractivity} =
		589	$self->{_wactivity} = AE::now;
		590
		591	$self->{read_size} ||= 2048;
		592	$self->{max_read_size} = $self->{read_size}
		593	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		594
		595	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		596	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		597	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		598
		599	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		600	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		601
		602	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		603
179	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	604	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
180	}	605	if $self->{tls};
181		606
182	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
183	$self->on_error (delete $self->{on_error}) if $self->{on_error};
184	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	607	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
185	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
186		608
187	$self->start_read;	609	$self->start_read
		610	if $self->{on_read} || @{ $self->{_queue} };
188		611
189	$self	612	$self->_drain_wbuf;
190	}	613	}
191		614
192	sub _shutdown {
193	my ($self) = @_;
194
195	delete $self->{rw};
196	delete $self->{ww};
197	delete $self->{fh};
198	}
199
200	sub error {	615	sub _error {
201	my ($self) = @_;	616	my ($self, $errno, $fatal, $message) = @_;
202		617
203	{	618	$! = $errno;
204	local $!;	619	$message ||= "$!";
205	$self->_shutdown;
206	}
207		620
208	if ($self->{on_error}) {	621	if ($self->{on_error}) {
209	$self->{on_error}($self);	622	$self->{on_error}($self, $fatal, $message);
210	} else {	623	$self->destroy if $fatal;
		624	} elsif ($self->{fh} || $self->{connect}) {
		625	$self->destroy;
211	die "AnyEvent::Handle uncaught fatal error: $!";	626	Carp::croak "AnyEvent::Handle uncaught error: $message";
212	}	627	}
213	}	628	}
214		629
215	=item $fh = $handle->fh	630	=item $fh = $handle->fh
216		631
217	This method returns the filehandle of the L<AnyEvent::Handle> object.	632	This method returns the file handle used to create the L<AnyEvent::Handle> object.
218		633
219	=cut	634	=cut
220		635
221	sub fh { $_[0]->{fh} }	636	sub fh { $_[0]{fh} }
222		637
223	=item $handle->on_error ($cb)	638	=item $handle->on_error ($cb)
224		639
225	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	640	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
226		641
…		…
238		653
239	sub on_eof {	654	sub on_eof {
240	$_[0]{on_eof} = $_[1];	655	$_[0]{on_eof} = $_[1];
241	}	656	}
242		657
		658	=item $handle->on_timeout ($cb)
		659
		660	=item $handle->on_rtimeout ($cb)
		661
		662	=item $handle->on_wtimeout ($cb)
		663
		664	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		665	callback, or disables the callback (but not the timeout) if C<$cb> =
		666	C<undef>. See the C<timeout> constructor argument and method.
		667
		668	=cut
		669
		670	# see below
		671
		672	=item $handle->autocork ($boolean)
		673
		674	Enables or disables the current autocork behaviour (see C<autocork>
		675	constructor argument). Changes will only take effect on the next write.
		676
		677	=cut
		678
		679	sub autocork {
		680	$_[0]{autocork} = $_[1];
		681	}
		682
		683	=item $handle->no_delay ($boolean)
		684
		685	Enables or disables the C<no_delay> setting (see constructor argument of
		686	the same name for details).
		687
		688	=cut
		689
		690	sub no_delay {
		691	$_[0]{no_delay} = $_[1];
		692
		693	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		694	if $_[0]{fh};
		695	}
		696
		697	=item $handle->keepalive ($boolean)
		698
		699	Enables or disables the C<keepalive> setting (see constructor argument of
		700	the same name for details).
		701
		702	=cut
		703
		704	sub keepalive {
		705	$_[0]{keepalive} = $_[1];
		706
		707	eval {
		708	local $SIG{__DIE__};
		709	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		710	if $_[0]{fh};
		711	};
		712	}
		713
		714	=item $handle->oobinline ($boolean)
		715
		716	Enables or disables the C<oobinline> setting (see constructor argument of
		717	the same name for details).
		718
		719	=cut
		720
		721	sub oobinline {
		722	$_[0]{oobinline} = $_[1];
		723
		724	eval {
		725	local $SIG{__DIE__};
		726	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		727	if $_[0]{fh};
		728	};
		729	}
		730
		731	=item $handle->keepalive ($boolean)
		732
		733	Enables or disables the C<keepalive> setting (see constructor argument of
		734	the same name for details).
		735
		736	=cut
		737
		738	sub keepalive {
		739	$_[0]{keepalive} = $_[1];
		740
		741	eval {
		742	local $SIG{__DIE__};
		743	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		744	if $_[0]{fh};
		745	};
		746	}
		747
		748	=item $handle->on_starttls ($cb)
		749
		750	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		751
		752	=cut
		753
		754	sub on_starttls {
		755	$_[0]{on_starttls} = $_[1];
		756	}
		757
		758	=item $handle->on_stoptls ($cb)
		759
		760	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		761
		762	=cut
		763
		764	sub on_stoptls {
		765	$_[0]{on_stoptls} = $_[1];
		766	}
		767
		768	=item $handle->rbuf_max ($max_octets)
		769
		770	Configures the C<rbuf_max> setting (C<undef> disables it).
		771
		772	=item $handle->wbuf_max ($max_octets)
		773
		774	Configures the C<wbuf_max> setting (C<undef> disables it).
		775
		776	=cut
		777
		778	sub rbuf_max {
		779	$_[0]{rbuf_max} = $_[1];
		780	}
		781
		782	sub wbuf_max {
		783	$_[0]{wbuf_max} = $_[1];
		784	}
		785
		786	#############################################################################
		787
		788	=item $handle->timeout ($seconds)
		789
		790	=item $handle->rtimeout ($seconds)
		791
		792	=item $handle->wtimeout ($seconds)
		793
		794	Configures (or disables) the inactivity timeout.
		795
		796	The timeout will be checked instantly, so this method might destroy the
		797	handle before it returns.
		798
		799	=item $handle->timeout_reset
		800
		801	=item $handle->rtimeout_reset
		802
		803	=item $handle->wtimeout_reset
		804
		805	Reset the activity timeout, as if data was received or sent.
		806
		807	These methods are cheap to call.
		808
		809	=cut
		810
		811	for my $dir ("", "r", "w") {
		812	my $timeout = "${dir}timeout";
		813	my $tw = "_${dir}tw";
		814	my $on_timeout = "on_${dir}timeout";
		815	my $activity = "_${dir}activity";
		816	my $cb;
		817
		818	*$on_timeout = sub {
		819	$_[0]{$on_timeout} = $_[1];
		820	};
		821
		822	*$timeout = sub {
		823	my ($self, $new_value) = @_;
		824
		825	$new_value >= 0
		826	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		827
		828	$self->{$timeout} = $new_value;
		829	delete $self->{$tw}; &$cb;
		830	};
		831
		832	*{"${dir}timeout_reset"} = sub {
		833	$_[0]{$activity} = AE::now;
		834	};
		835
		836	# main workhorse:
		837	# reset the timeout watcher, as neccessary
		838	# also check for time-outs
		839	$cb = sub {
		840	my ($self) = @_;
		841
		842	if ($self->{$timeout} && $self->{fh}) {
		843	my $NOW = AE::now;
		844
		845	# when would the timeout trigger?
		846	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		847
		848	# now or in the past already?
		849	if ($after <= 0) {
		850	$self->{$activity} = $NOW;
		851
		852	if ($self->{$on_timeout}) {
		853	$self->{$on_timeout}($self);
		854	} else {
		855	$self->_error (Errno::ETIMEDOUT);
		856	}
		857
		858	# callback could have changed timeout value, optimise
		859	return unless $self->{$timeout};
		860
		861	# calculate new after
		862	$after = $self->{$timeout};
		863	}
		864
		865	Scalar::Util::weaken $self;
		866	return unless $self; # ->error could have destroyed $self
		867
		868	$self->{$tw} ||= AE::timer $after, 0, sub {
		869	delete $self->{$tw};
		870	$cb->($self);
		871	};
		872	} else {
		873	delete $self->{$tw};
		874	}
		875	}
		876	}
		877
243	#############################################################################	878	#############################################################################
244		879
245	=back	880	=back
246		881
247	=head2 WRITE QUEUE	882	=head2 WRITE QUEUE
…		…
251		886
252	The write queue is very simple: you can add data to its end, and	887	The write queue is very simple: you can add data to its end, and
253	AnyEvent::Handle will automatically try to get rid of it for you.	888	AnyEvent::Handle will automatically try to get rid of it for you.
254		889
255	When data could be written and the write buffer is shorter then the low	890	When data could be written and the write buffer is shorter then the low
256	water mark, the C<on_drain> callback will be invoked.	891	water mark, the C<on_drain> callback will be invoked once.
257		892
258	=over 4	893	=over 4
259		894
260	=item $handle->on_drain ($cb)	895	=item $handle->on_drain ($cb)
261		896
262	Sets the C<on_drain> callback or clears it (see the description of	897	Sets the C<on_drain> callback or clears it (see the description of
263	C<on_drain> in the constructor).	898	C<on_drain> in the constructor).
264		899
		900	This method may invoke callbacks (and therefore the handle might be
		901	destroyed after it returns).
		902
265	=cut	903	=cut
266		904
267	sub on_drain {	905	sub on_drain {
268	my ($self, $cb) = @_;	906	my ($self, $cb) = @_;
269		907
270	$self->{on_drain} = $cb;	908	$self->{on_drain} = $cb;
271		909
272	$cb->($self)	910	$cb->($self)
273	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	911	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
274	}	912	}
275		913
276	=item $handle->push_write ($data)	914	=item $handle->push_write ($data)
277		915
278	Queues the given scalar to be written. You can push as much data as you	916	Queues the given scalar to be written. You can push as much data as
279	want (only limited by the available memory), as C<AnyEvent::Handle>	917	you want (only limited by the available memory and C<wbuf_max>), as
280	buffers it independently of the kernel.	918	C<AnyEvent::Handle> buffers it independently of the kernel.
		919
		920	This method may invoke callbacks (and therefore the handle might be
		921	destroyed after it returns).
281		922
282	=cut	923	=cut
283		924
284	sub _drain_wbuf {	925	sub _drain_wbuf {
285	my ($self) = @_;	926	my ($self) = @_;
286		927
287	unless ($self->{ww}) {	928	if (!$self->{_ww} && length $self->{wbuf}) {
		929
288	Scalar::Util::weaken $self;	930	Scalar::Util::weaken $self;
		931
289	my $cb = sub {	932	my $cb = sub {
290	my $len = syswrite $self->{fh}, $self->{wbuf};	933	my $len = syswrite $self->{fh}, $self->{wbuf};
291		934
292	if ($len > 0) {	935	if (defined $len) {
293	substr $self->{wbuf}, 0, $len, "";	936	substr $self->{wbuf}, 0, $len, "";
294		937
		938	$self->{_activity} = $self->{_wactivity} = AE::now;
		939
295	$self->{on_drain}($self)	940	$self->{on_drain}($self)
296	if $self->{low_water_mark} >= length $self->{wbuf}	941	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
297	&& $self->{on_drain};	942	&& $self->{on_drain};
298		943
299	delete $self->{ww} unless length $self->{wbuf};	944	delete $self->{_ww} unless length $self->{wbuf};
300	} elsif ($! != EAGAIN && $! != EINTR) {	945	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
301	$self->error;	946	$self->_error ($!, 1);
302	}	947	}
303	};	948	};
304		949
305	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	950	# try to write data immediately
		951	$cb->() unless $self->{autocork};
306		952
307	$cb->($self);	953	# if still data left in wbuf, we need to poll
		954	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		955	if length $self->{wbuf};
		956
		957	if (
		958	defined $self->{wbuf_max}
		959	&& $self->{wbuf_max} < length $self->{wbuf}
		960	) {
		961	$self->_error (Errno::ENOSPC, 1), return;
		962	}
308	};	963	};
		964	}
		965
		966	our %WH;
		967
		968	# deprecated
		969	sub register_write_type($$) {
		970	$WH{$_[0]} = $_[1];
309	}	971	}
310		972
311	sub push_write {	973	sub push_write {
312	my $self = shift;	974	my $self = shift;
313		975
		976	if (@_ > 1) {
		977	my $type = shift;
		978
		979	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
		980	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
		981	->($self, @_);
		982	}
		983
		984	# we downgrade here to avoid hard-to-track-down bugs,
		985	# and diagnose the problem earlier and better.
		986
314	if ($self->{filter_w}) {	987	if ($self->{tls}) {
315	$self->{filter_w}->($self, \$_[0]);	988	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		989	&_dotls ($self) if $self->{fh};
316	} else {	990	} else {
317	$self->{wbuf} .= $_[0];	991	utf8::downgrade $self->{wbuf} .= $_[0];
318	$self->_drain_wbuf;	992	$self->_drain_wbuf if $self->{fh};
319	}	993	}
320	}	994	}
		995
		996	=item $handle->push_write (type => @args)
		997
		998	Instead of formatting your data yourself, you can also let this module
		999	do the job by specifying a type and type-specific arguments. You
		1000	can also specify the (fully qualified) name of a package, in which
		1001	case AnyEvent tries to load the package and then expects to find the
		1002	C<anyevent_write_type> function inside (see "custom write types", below).
		1003
		1004	Predefined types are (if you have ideas for additional types, feel free to
		1005	drop by and tell us):
		1006
		1007	=over 4
		1008
		1009	=item netstring => $string
		1010
		1011	Formats the given value as netstring
		1012	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		1013
		1014	=cut
		1015
		1016	register_write_type netstring => sub {
		1017	my ($self, $string) = @_;
		1018
		1019	(length $string) . ":$string,"
		1020	};
		1021
		1022	=item packstring => $format, $data
		1023
		1024	An octet string prefixed with an encoded length. The encoding C<$format>
		1025	uses the same format as a Perl C<pack> format, but must specify a single
		1026	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1027	optional C<!>, C<< < >> or C<< > >> modifier).
		1028
		1029	=cut
		1030
		1031	register_write_type packstring => sub {
		1032	my ($self, $format, $string) = @_;
		1033
		1034	pack "$format/a*", $string
		1035	};
		1036
		1037	=item json => $array_or_hashref
		1038
		1039	Encodes the given hash or array reference into a JSON object. Unless you
		1040	provide your own JSON object, this means it will be encoded to JSON text
		1041	in UTF-8.
		1042
		1043	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		1044	one end of a handle and read them at the other end without using any
		1045	additional framing.
		1046
		1047	The generated JSON text is guaranteed not to contain any newlines: While
		1048	this module doesn't need delimiters after or between JSON texts to be
		1049	able to read them, many other languages depend on that.
		1050
		1051	A simple RPC protocol that interoperates easily with others is to send
		1052	JSON arrays (or objects, although arrays are usually the better choice as
		1053	they mimic how function argument passing works) and a newline after each
		1054	JSON text:
		1055
		1056	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		1057	$handle->push_write ("\012");
		1058
		1059	An AnyEvent::Handle receiver would simply use the C<json> read type and
		1060	rely on the fact that the newline will be skipped as leading whitespace:
		1061
		1062	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1063
		1064	Other languages could read single lines terminated by a newline and pass
		1065	this line into their JSON decoder of choice.
		1066
		1067	=cut
		1068
		1069	sub json_coder() {
		1070	eval { require JSON::XS; JSON::XS->new->utf8 }
		1071	|| do { require JSON; JSON->new->utf8 }
		1072	}
		1073
		1074	register_write_type json => sub {
		1075	my ($self, $ref) = @_;
		1076
		1077	my $json = $self->{json} ||= json_coder;
		1078
		1079	$json->encode ($ref)
		1080	};
		1081
		1082	=item storable => $reference
		1083
		1084	Freezes the given reference using L<Storable> and writes it to the
		1085	handle. Uses the C<nfreeze> format.
		1086
		1087	=cut
		1088
		1089	register_write_type storable => sub {
		1090	my ($self, $ref) = @_;
		1091
		1092	require Storable unless $Storable::VERSION;
		1093
		1094	pack "w/a*", Storable::nfreeze ($ref)
		1095	};
		1096
		1097	=back
		1098
		1099	=item $handle->push_shutdown
		1100
		1101	Sometimes you know you want to close the socket after writing your data
		1102	before it was actually written. One way to do that is to replace your
		1103	C<on_drain> handler by a callback that shuts down the socket (and set
		1104	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1105	replaces the C<on_drain> callback with:
		1106
		1107	sub { shutdown $_[0]{fh}, 1 }
		1108
		1109	This simply shuts down the write side and signals an EOF condition to the
		1110	the peer.
		1111
		1112	You can rely on the normal read queue and C<on_eof> handling
		1113	afterwards. This is the cleanest way to close a connection.
		1114
		1115	This method may invoke callbacks (and therefore the handle might be
		1116	destroyed after it returns).
		1117
		1118	=cut
		1119
		1120	sub push_shutdown {
		1121	my ($self) = @_;
		1122
		1123	delete $self->{low_water_mark};
		1124	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1125	}
		1126
		1127	=item custom write types - Package::anyevent_write_type $handle, @args
		1128
		1129	Instead of one of the predefined types, you can also specify the name of
		1130	a package. AnyEvent will try to load the package and then expects to find
		1131	a function named C<anyevent_write_type> inside. If it isn't found, it
		1132	progressively tries to load the parent package until it either finds the
		1133	function (good) or runs out of packages (bad).
		1134
		1135	Whenever the given C<type> is used, C<push_write> will the function with
		1136	the handle object and the remaining arguments.
		1137
		1138	The function is supposed to return a single octet string that will be
		1139	appended to the write buffer, so you can mentally treat this function as a
		1140	"arguments to on-the-wire-format" converter.
		1141
		1142	Example: implement a custom write type C<join> that joins the remaining
		1143	arguments using the first one.
		1144
		1145	$handle->push_write (My::Type => " ", 1,2,3);
		1146
		1147	# uses the following package, which can be defined in the "My::Type" or in
		1148	# the "My" modules to be auto-loaded, or just about anywhere when the
		1149	# My::Type::anyevent_write_type is defined before invoking it.
		1150
		1151	package My::Type;
		1152
		1153	sub anyevent_write_type {
		1154	my ($handle, $delim, @args) = @_;
		1155
		1156	join $delim, @args
		1157	}
		1158
		1159	=cut
321		1160
322	#############################################################################	1161	#############################################################################
323		1162
324	=back	1163	=back
325		1164
…		…
332	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1171	ways, the "simple" way, using only C<on_read> and the "complex" way, using
333	a queue.	1172	a queue.
334		1173
335	In the simple case, you just install an C<on_read> callback and whenever	1174	In the simple case, you just install an C<on_read> callback and whenever
336	new data arrives, it will be called. You can then remove some data (if	1175	new data arrives, it will be called. You can then remove some data (if
337	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1176	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
338	or not.	1177	leave the data there if you want to accumulate more (e.g. when only a
		1178	partial message has been received so far), or change the read queue with
		1179	e.g. C<push_read>.
339		1180
340	In the more complex case, you want to queue multiple callbacks. In this	1181	In the more complex case, you want to queue multiple callbacks. In this
341	case, AnyEvent::Handle will call the first queued callback each time new	1182	case, AnyEvent::Handle will call the first queued callback each time new
342	data arrives and removes it when it has done its job (see C<push_read>,	1183	data arrives (also the first time it is queued) and remove it when it has
343	below).	1184	done its job (see C<push_read>, below).
344		1185
345	This way you can, for example, push three line-reads, followed by reading	1186	This way you can, for example, push three line-reads, followed by reading
346	a chunk of data, and AnyEvent::Handle will execute them in order.	1187	a chunk of data, and AnyEvent::Handle will execute them in order.
347		1188
348	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1189	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
349	the specified number of bytes which give an XML datagram.	1190	the specified number of bytes which give an XML datagram.
350		1191
351	# in the default state, expect some header bytes	1192	# in the default state, expect some header bytes
352	$handle->on_read (sub {	1193	$handle->on_read (sub {
353	# some data is here, now queue the length-header-read (4 octets)	1194	# some data is here, now queue the length-header-read (4 octets)
354	shift->unshift_read_chunk (4, sub {	1195	shift->unshift_read (chunk => 4, sub {
355	# header arrived, decode	1196	# header arrived, decode
356	my $len = unpack "N", $_[1];	1197	my $len = unpack "N", $_[1];
357		1198
358	# now read the payload	1199	# now read the payload
359	shift->unshift_read_chunk ($len, sub {	1200	shift->unshift_read (chunk => $len, sub {
360	my $xml = $_[1];	1201	my $xml = $_[1];
361	# handle xml	1202	# handle xml
362	});	1203	});
363	});	1204	});
364	});	1205	});
365		1206
366	Example 2: Implement a client for a protocol that replies either with	1207	Example 2: Implement a client for a protocol that replies either with "OK"
367	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1208	and another line or "ERROR" for the first request that is sent, and 64
368	second request. Due tot he availability of a full queue, we can just	1209	bytes for the second request. Due to the availability of a queue, we can
369	pipeline sending both requests and manipulate the queue as necessary in	1210	just pipeline sending both requests and manipulate the queue as necessary
370	the callbacks:	1211	in the callbacks.
371		1212
372	# request one	1213	When the first callback is called and sees an "OK" response, it will
		1214	C<unshift> another line-read. This line-read will be queued I<before> the
		1215	64-byte chunk callback.
		1216
		1217	# request one, returns either "OK + extra line" or "ERROR"
373	$handle->push_write ("request 1\015\012");	1218	$handle->push_write ("request 1\015\012");
374		1219
375	# we expect "ERROR" or "OK" as response, so push a line read	1220	# we expect "ERROR" or "OK" as response, so push a line read
376	$handle->push_read_line (sub {	1221	$handle->push_read (line => sub {
377	# if we got an "OK", we have to _prepend_ another line,	1222	# if we got an "OK", we have to _prepend_ another line,
378	# so it will be read before the second request reads its 64 bytes	1223	# so it will be read before the second request reads its 64 bytes
379	# which are already in the queue when this callback is called	1224	# which are already in the queue when this callback is called
380	# we don't do this in case we got an error	1225	# we don't do this in case we got an error
381	if ($_[1] eq "OK") {	1226	if ($_[1] eq "OK") {
382	$_[0]->unshift_read_line (sub {	1227	$_[0]->unshift_read (line => sub {
383	my $response = $_[1];	1228	my $response = $_[1];
384	...	1229	...
385	});	1230	});
386	}	1231	}
387	});	1232	});
388		1233
389	# request two	1234	# request two, simply returns 64 octets
390	$handle->push_write ("request 2\015\012");	1235	$handle->push_write ("request 2\015\012");
391		1236
392	# simply read 64 bytes, always	1237	# simply read 64 bytes, always
393	$handle->push_read_chunk (64, sub {	1238	$handle->push_read (chunk => 64, sub {
394	my $response = $_[1];	1239	my $response = $_[1];
395	...	1240	...
396	});	1241	});
397		1242
398	=over 4	1243	=over 4
399		1244
400	=cut	1245	=cut
401		1246
402	sub _drain_rbuf {	1247	sub _drain_rbuf {
403	my ($self) = @_;	1248	my ($self) = @_;
		1249
		1250	# avoid recursion
		1251	return if $self->{_skip_drain_rbuf};
		1252	local $self->{_skip_drain_rbuf} = 1;
		1253
		1254	while () {
		1255	# we need to use a separate tls read buffer, as we must not receive data while
		1256	# we are draining the buffer, and this can only happen with TLS.
		1257	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1258	if exists $self->{_tls_rbuf};
		1259
		1260	my $len = length $self->{rbuf};
		1261
		1262	if (my $cb = shift @{ $self->{_queue} }) {
		1263	unless ($cb->($self)) {
		1264	# no progress can be made
		1265	# (not enough data and no data forthcoming)
		1266	$self->_error (Errno::EPIPE, 1), return
		1267	if $self->{_eof};
		1268
		1269	unshift @{ $self->{_queue} }, $cb;
		1270	last;
		1271	}
		1272	} elsif ($self->{on_read}) {
		1273	last unless $len;
		1274
		1275	$self->{on_read}($self);
		1276
		1277	if (
		1278	$len == length $self->{rbuf} # if no data has been consumed
		1279	&& !@{ $self->{_queue} } # and the queue is still empty
		1280	&& $self->{on_read} # but we still have on_read
		1281	) {
		1282	# no further data will arrive
		1283	# so no progress can be made
		1284	$self->_error (Errno::EPIPE, 1), return
		1285	if $self->{_eof};
		1286
		1287	last; # more data might arrive
		1288	}
		1289	} else {
		1290	# read side becomes idle
		1291	delete $self->{_rw} unless $self->{tls};
		1292	last;
		1293	}
		1294	}
		1295
		1296	if ($self->{_eof}) {
		1297	$self->{on_eof}
		1298	? $self->{on_eof}($self)
		1299	: $self->_error (0, 1, "Unexpected end-of-file");
		1300
		1301	return;
		1302	}
404		1303
405	if (	1304	if (
406	defined $self->{rbuf_max}	1305	defined $self->{rbuf_max}
407	&& $self->{rbuf_max} < length $self->{rbuf}	1306	&& $self->{rbuf_max} < length $self->{rbuf}
408	) {	1307	) {
409	$! = &Errno::ENOSPC; return $self->error;	1308	$self->_error (Errno::ENOSPC, 1), return;
410	}	1309	}
411		1310
412	return if $self->{in_drain};	1311	# may need to restart read watcher
413	local $self->{in_drain} = 1;	1312	unless ($self->{_rw}) {
414		1313	$self->start_read
415	while (my $len = length $self->{rbuf}) {	1314	if $self->{on_read} || @{ $self->{_queue} };
416	no strict 'refs';
417	if (my $cb = shift @{ $self->{queue} }) {
418	if (!$cb->($self)) {
419	if ($self->{eof}) {
420	# no progress can be made (not enough data and no data forthcoming)
421	$! = &Errno::EPIPE; return $self->error;
422	}
423
424	unshift @{ $self->{queue} }, $cb;
425	return;
426	}
427	} elsif ($self->{on_read}) {
428	$self->{on_read}($self);
429
430	if (
431	$self->{eof} # if no further data will arrive
432	&& $len == length $self->{rbuf} # and no data has been consumed
433	&& !@{ $self->{queue} } # and the queue is still empty
434	&& $self->{on_read} # and we still want to read data
435	) {
436	# then no progress can be made
437	$! = &Errno::EPIPE; return $self->error;
438	}
439	} else {
440	# read side becomes idle
441	delete $self->{rw};
442	return;
443	}
444	}
445
446	if ($self->{eof}) {
447	$self->_shutdown;
448	$self->{on_eof}($self)
449	if $self->{on_eof};
450	}	1315	}
451	}	1316	}
452		1317
453	=item $handle->on_read ($cb)	1318	=item $handle->on_read ($cb)
454		1319
455	This replaces the currently set C<on_read> callback, or clears it (when	1320	This replaces the currently set C<on_read> callback, or clears it (when
456	the new callback is C<undef>). See the description of C<on_read> in the	1321	the new callback is C<undef>). See the description of C<on_read> in the
457	constructor.	1322	constructor.
458		1323
		1324	This method may invoke callbacks (and therefore the handle might be
		1325	destroyed after it returns).
		1326
459	=cut	1327	=cut
460		1328
461	sub on_read {	1329	sub on_read {
462	my ($self, $cb) = @_;	1330	my ($self, $cb) = @_;
463		1331
464	$self->{on_read} = $cb;	1332	$self->{on_read} = $cb;
		1333	$self->_drain_rbuf if $cb;
465	}	1334	}
466		1335
467	=item $handle->rbuf	1336	=item $handle->rbuf
468		1337
469	Returns the read buffer (as a modifiable lvalue).	1338	Returns the read buffer (as a modifiable lvalue). You can also access the
		1339	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1340	much faster, and no less clean).
470		1341
471	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1342	The only operation allowed on the read buffer (apart from looking at it)
472	you want.	1343	is removing data from its beginning. Otherwise modifying or appending to
		1344	it is not allowed and will lead to hard-to-track-down bugs.
473		1345
474	NOTE: The read buffer should only be used or modified if the C<on_read>,	1346	NOTE: The read buffer should only be used or modified in the C<on_read>
475	C<push_read> or C<unshift_read> methods are used. The other read methods	1347	callback or when C<push_read> or C<unshift_read> are used with a single
476	automatically manage the read buffer.	1348	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1349	will manage the read buffer on their own.
477		1350
478	=cut	1351	=cut
479		1352
480	sub rbuf : lvalue {	1353	sub rbuf : lvalue {
481	$_[0]{rbuf}	1354	$_[0]{rbuf}
…		…
498		1371
499	If enough data was available, then the callback must remove all data it is	1372	If enough data was available, then the callback must remove all data it is
500	interested in (which can be none at all) and return a true value. After returning	1373	interested in (which can be none at all) and return a true value. After returning
501	true, it will be removed from the queue.	1374	true, it will be removed from the queue.
502		1375
		1376	These methods may invoke callbacks (and therefore the handle might be
		1377	destroyed after it returns).
		1378
503	=cut	1379	=cut
		1380
		1381	our %RH;
		1382
		1383	sub register_read_type($$) {
		1384	$RH{$_[0]} = $_[1];
		1385	}
504		1386
505	sub push_read {	1387	sub push_read {
506	my ($self, $cb) = @_;	1388	my $self = shift;
		1389	my $cb = pop;
507		1390
		1391	if (@_) {
		1392	my $type = shift;
		1393
		1394	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1395	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
		1396	->($self, $cb, @_);
		1397	}
		1398
508	push @{ $self->{queue} }, $cb;	1399	push @{ $self->{_queue} }, $cb;
509	$self->_drain_rbuf;	1400	$self->_drain_rbuf;
510	}	1401	}
511		1402
512	sub unshift_read {	1403	sub unshift_read {
513	my ($self, $cb) = @_;	1404	my $self = shift;
		1405	my $cb = pop;
514		1406
		1407	if (@_) {
		1408	my $type = shift;
		1409
		1410	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1411	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
		1412	->($self, $cb, @_);
		1413	}
		1414
515	push @{ $self->{queue} }, $cb;	1415	unshift @{ $self->{_queue} }, $cb;
516	$self->_drain_rbuf;	1416	$self->_drain_rbuf;
517	}	1417	}
518		1418
519	=item $handle->push_read_chunk ($len, $cb->($self, $data))	1419	=item $handle->push_read (type => @args, $cb)
520		1420
521	=item $handle->unshift_read_chunk ($len, $cb->($self, $data))	1421	=item $handle->unshift_read (type => @args, $cb)
522		1422
523	Append the given callback to the end of the queue (C<push_read_chunk>) or	1423	Instead of providing a callback that parses the data itself you can chose
524	prepend it (C<unshift_read_chunk>).	1424	between a number of predefined parsing formats, for chunks of data, lines
		1425	etc. You can also specify the (fully qualified) name of a package, in
		1426	which case AnyEvent tries to load the package and then expects to find the
		1427	C<anyevent_read_type> function inside (see "custom read types", below).
525		1428
526	The callback will be called only once C<$len> bytes have been read, and	1429	Predefined types are (if you have ideas for additional types, feel free to
527	these C<$len> bytes will be passed to the callback.	1430	drop by and tell us):
528		1431
529	=cut	1432	=over 4
530		1433
531	sub _read_chunk($$) {	1434	=item chunk => $octets, $cb->($handle, $data)
		1435
		1436	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1437	data read to the callback. The callback will never be called with less
		1438	data.
		1439
		1440	Example: read 2 bytes.
		1441
		1442	$handle->push_read (chunk => 2, sub {
		1443	say "yay " . unpack "H*", $_[1];
		1444	});
		1445
		1446	=cut
		1447
		1448	register_read_type chunk => sub {
532	my ($self, $len, $cb) = @_;	1449	my ($self, $cb, $len) = @_;
533		1450
534	sub {	1451	sub {
535	$len <= length $_[0]{rbuf} or return;	1452	$len <= length $_[0]{rbuf} or return;
536	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1453	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
537	1	1454	1
538	}	1455	}
539	}	1456	};
540		1457
541	sub push_read_chunk {	1458	=item line => [$eol, ]$cb->($handle, $line, $eol)
542	$_[0]->push_read (&_read_chunk);
543	}
544
545
546	sub unshift_read_chunk {
547	$_[0]->unshift_read (&_read_chunk);
548	}
549
550	=item $handle->push_read_line ([$eol, ]$cb->($self, $line, $eol))
551
552	=item $handle->unshift_read_line ([$eol, ]$cb->($self, $line, $eol))
553
554	Append the given callback to the end of the queue (C<push_read_line>) or
555	prepend it (C<unshift_read_line>).
556		1459
557	The callback will be called only once a full line (including the end of	1460	The callback will be called only once a full line (including the end of
558	line marker, C<$eol>) has been read. This line (excluding the end of line	1461	line marker, C<$eol>) has been read. This line (excluding the end of line
559	marker) will be passed to the callback as second argument (C<$line>), and	1462	marker) will be passed to the callback as second argument (C<$line>), and
560	the end of line marker as the third argument (C<$eol>).	1463	the end of line marker as the third argument (C<$eol>).
…		…
571	Partial lines at the end of the stream will never be returned, as they are	1474	Partial lines at the end of the stream will never be returned, as they are
572	not marked by the end of line marker.	1475	not marked by the end of line marker.
573		1476
574	=cut	1477	=cut
575		1478
576	sub _read_line($$) {	1479	register_read_type line => sub {
577	my $self = shift;	1480	my ($self, $cb, $eol) = @_;
578	my $cb = pop;
579	my $eol = @_ ? shift : qr|(\015?\012)|;
580	my $pos;
581		1481
		1482	if (@_ < 3) {
		1483	# this is more than twice as fast as the generic code below
		1484	sub {
		1485	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1486
		1487	$cb->($_[0], "$1", "$2");
		1488	1
		1489	}
		1490	} else {
582	$eol = quotemeta $eol unless ref $eol;	1491	$eol = quotemeta $eol unless ref $eol;
583	$eol = qr|^(.*?)($eol)|s;	1492	$eol = qr|^(.*?)($eol)|s;
		1493
		1494	sub {
		1495	$_[0]{rbuf} =~ s/$eol// or return;
		1496
		1497	$cb->($_[0], "$1", "$2");
		1498	1
		1499	}
		1500	}
		1501	};
		1502
		1503	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1504
		1505	Makes a regex match against the regex object C<$accept> and returns
		1506	everything up to and including the match.
		1507
		1508	Example: read a single line terminated by '\n'.
		1509
		1510	$handle->push_read (regex => qr<\n>, sub { ... });
		1511
		1512	If C<$reject> is given and not undef, then it determines when the data is
		1513	to be rejected: it is matched against the data when the C<$accept> regex
		1514	does not match and generates an C<EBADMSG> error when it matches. This is
		1515	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1516	receive buffer overflow).
		1517
		1518	Example: expect a single decimal number followed by whitespace, reject
		1519	anything else (not the use of an anchor).
		1520
		1521	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1522
		1523	If C<$skip> is given and not C<undef>, then it will be matched against
		1524	the receive buffer when neither C<$accept> nor C<$reject> match,
		1525	and everything preceding and including the match will be accepted
		1526	unconditionally. This is useful to skip large amounts of data that you
		1527	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1528	have to start matching from the beginning. This is purely an optimisation
		1529	and is usually worth it only when you expect more than a few kilobytes.
		1530
		1531	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1532	expect the header to be very large (it isn't in practice, but...), we use
		1533	a skip regex to skip initial portions. The skip regex is tricky in that
		1534	it only accepts something not ending in either \015 or \012, as these are
		1535	required for the accept regex.
		1536
		1537	$handle->push_read (regex =>
		1538	qr<\015\012\015\012>,
		1539	undef, # no reject
		1540	qr<^.*[^\015\012]>,
		1541	sub { ... });
		1542
		1543	=cut
		1544
		1545	register_read_type regex => sub {
		1546	my ($self, $cb, $accept, $reject, $skip) = @_;
		1547
		1548	my $data;
		1549	my $rbuf = \$self->{rbuf};
584		1550
585	sub {	1551	sub {
586	$_[0]{rbuf} =~ s/$eol// or return;	1552	# accept
587		1553	if ($$rbuf =~ $accept) {
		1554	$data .= substr $$rbuf, 0, $+[0], "";
588	$cb->($_[0], $1, $2);	1555	$cb->($_[0], $data);
		1556	return 1;
		1557	}
		1558
		1559	# reject
		1560	if ($reject && $$rbuf =~ $reject) {
		1561	$_[0]->_error (Errno::EBADMSG);
		1562	}
		1563
		1564	# skip
		1565	if ($skip && $$rbuf =~ $skip) {
		1566	$data .= substr $$rbuf, 0, $+[0], "";
		1567	}
		1568
		1569	()
		1570	}
		1571	};
		1572
		1573	=item netstring => $cb->($handle, $string)
		1574
		1575	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1576
		1577	Throws an error with C<$!> set to EBADMSG on format violations.
		1578
		1579	=cut
		1580
		1581	register_read_type netstring => sub {
		1582	my ($self, $cb) = @_;
		1583
		1584	sub {
		1585	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1586	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1587	$_[0]->_error (Errno::EBADMSG);
		1588	}
		1589	return;
		1590	}
		1591
		1592	my $len = $1;
		1593
		1594	$_[0]->unshift_read (chunk => $len, sub {
		1595	my $string = $_[1];
		1596	$_[0]->unshift_read (chunk => 1, sub {
		1597	if ($_[1] eq ",") {
		1598	$cb->($_[0], $string);
		1599	} else {
		1600	$_[0]->_error (Errno::EBADMSG);
		1601	}
		1602	});
		1603	});
		1604
589	1	1605	1
590	}	1606	}
591	}	1607	};
592		1608
593	sub push_read_line {	1609	=item packstring => $format, $cb->($handle, $string)
594	$_[0]->push_read (&_read_line);
595	}
596		1610
597	sub unshift_read_line {	1611	An octet string prefixed with an encoded length. The encoding C<$format>
598	$_[0]->unshift_read (&_read_line);	1612	uses the same format as a Perl C<pack> format, but must specify a single
599	}	1613	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1614	optional C<!>, C<< < >> or C<< > >> modifier).
		1615
		1616	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1617	EPP uses a prefix of C<N> (4 octtes).
		1618
		1619	Example: read a block of data prefixed by its length in BER-encoded
		1620	format (very efficient).
		1621
		1622	$handle->push_read (packstring => "w", sub {
		1623	my ($handle, $data) = @_;
		1624	});
		1625
		1626	=cut
		1627
		1628	register_read_type packstring => sub {
		1629	my ($self, $cb, $format) = @_;
		1630
		1631	sub {
		1632	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1633	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1634	or return;
		1635
		1636	$format = length pack $format, $len;
		1637
		1638	# bypass unshift if we already have the remaining chunk
		1639	if ($format + $len <= length $_[0]{rbuf}) {
		1640	my $data = substr $_[0]{rbuf}, $format, $len;
		1641	substr $_[0]{rbuf}, 0, $format + $len, "";
		1642	$cb->($_[0], $data);
		1643	} else {
		1644	# remove prefix
		1645	substr $_[0]{rbuf}, 0, $format, "";
		1646
		1647	# read remaining chunk
		1648	$_[0]->unshift_read (chunk => $len, $cb);
		1649	}
		1650
		1651	1
		1652	}
		1653	};
		1654
		1655	=item json => $cb->($handle, $hash_or_arrayref)
		1656
		1657	Reads a JSON object or array, decodes it and passes it to the
		1658	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1659
		1660	If a C<json> object was passed to the constructor, then that will be used
		1661	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1662
		1663	This read type uses the incremental parser available with JSON version
		1664	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1665	dependency on your own: this module will load the JSON module, but
		1666	AnyEvent does not depend on it itself.
		1667
		1668	Since JSON texts are fully self-delimiting, the C<json> read and write
		1669	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1670	the C<json> write type description, above, for an actual example.
		1671
		1672	=cut
		1673
		1674	register_read_type json => sub {
		1675	my ($self, $cb) = @_;
		1676
		1677	my $json = $self->{json} ||= json_coder;
		1678
		1679	my $data;
		1680	my $rbuf = \$self->{rbuf};
		1681
		1682	sub {
		1683	my $ref = eval { $json->incr_parse ($_[0]{rbuf}) };
		1684
		1685	if ($ref) {
		1686	$_[0]{rbuf} = $json->incr_text;
		1687	$json->incr_text = "";
		1688	$cb->($_[0], $ref);
		1689
		1690	1
		1691	} elsif ($@) {
		1692	# error case
		1693	$json->incr_skip;
		1694
		1695	$_[0]{rbuf} = $json->incr_text;
		1696	$json->incr_text = "";
		1697
		1698	$_[0]->_error (Errno::EBADMSG);
		1699
		1700	()
		1701	} else {
		1702	$_[0]{rbuf} = "";
		1703
		1704	()
		1705	}
		1706	}
		1707	};
		1708
		1709	=item storable => $cb->($handle, $ref)
		1710
		1711	Deserialises a L<Storable> frozen representation as written by the
		1712	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1713	data).
		1714
		1715	Raises C<EBADMSG> error if the data could not be decoded.
		1716
		1717	=cut
		1718
		1719	register_read_type storable => sub {
		1720	my ($self, $cb) = @_;
		1721
		1722	require Storable unless $Storable::VERSION;
		1723
		1724	sub {
		1725	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1726	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1727	or return;
		1728
		1729	my $format = length pack "w", $len;
		1730
		1731	# bypass unshift if we already have the remaining chunk
		1732	if ($format + $len <= length $_[0]{rbuf}) {
		1733	my $data = substr $_[0]{rbuf}, $format, $len;
		1734	substr $_[0]{rbuf}, 0, $format + $len, "";
		1735	$cb->($_[0], Storable::thaw ($data));
		1736	} else {
		1737	# remove prefix
		1738	substr $_[0]{rbuf}, 0, $format, "";
		1739
		1740	# read remaining chunk
		1741	$_[0]->unshift_read (chunk => $len, sub {
		1742	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1743	$cb->($_[0], $ref);
		1744	} else {
		1745	$_[0]->_error (Errno::EBADMSG);
		1746	}
		1747	});
		1748	}
		1749
		1750	1
		1751	}
		1752	};
		1753
		1754	=back
		1755
		1756	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
		1757
		1758	Instead of one of the predefined types, you can also specify the name
		1759	of a package. AnyEvent will try to load the package and then expects to
		1760	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1761	progressively tries to load the parent package until it either finds the
		1762	function (good) or runs out of packages (bad).
		1763
		1764	Whenever this type is used, C<push_read> will invoke the function with the
		1765	handle object, the original callback and the remaining arguments.
		1766
		1767	The function is supposed to return a callback (usually a closure) that
		1768	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1769	mentally treat the function as a "configurable read type to read callback"
		1770	converter.
		1771
		1772	It should invoke the original callback when it is done reading (remember
		1773	to pass C<$handle> as first argument as all other callbacks do that,
		1774	although there is no strict requirement on this).
		1775
		1776	For examples, see the source of this module (F<perldoc -m
		1777	AnyEvent::Handle>, search for C<register_read_type>)).
600		1778
601	=item $handle->stop_read	1779	=item $handle->stop_read
602		1780
603	=item $handle->start_read	1781	=item $handle->start_read
604		1782
605	In rare cases you actually do not want to read anything from the	1783	In rare cases you actually do not want to read anything from the
606	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1784	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
607	any queued callbacks will be executed then. To start readign again, call	1785	any queued callbacks will be executed then. To start reading again, call
608	C<start_read>.	1786	C<start_read>.
		1787
		1788	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1789	you change the C<on_read> callback or push/unshift a read callback, and it
		1790	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1791	there are any read requests in the queue.
		1792
		1793	In older versions of this module (<= 5.3), these methods had no effect,
		1794	as TLS does not support half-duplex connections. In current versions they
		1795	work as expected, as this behaviour is required to avoid certain resource
		1796	attacks, where the program would be forced to read (and buffer) arbitrary
		1797	amounts of data before being able to send some data. The drawback is that
		1798	some readings of the the SSL/TLS specifications basically require this
		1799	attack to be working, as SSL/TLS implementations might stall sending data
		1800	during a rehandshake.
		1801
		1802	As a guideline, during the initial handshake, you should not stop reading,
		1803	and as a client, it might cause problems, depending on your application.
609		1804
610	=cut	1805	=cut
611		1806
612	sub stop_read {	1807	sub stop_read {
613	my ($self) = @_;	1808	my ($self) = @_;
614		1809
615	delete $self->{rw};	1810	delete $self->{_rw};
616	}	1811	}
617		1812
618	sub start_read {	1813	sub start_read {
619	my ($self) = @_;	1814	my ($self) = @_;
620		1815
621	unless ($self->{rw} || $self->{eof}) {	1816	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
622	Scalar::Util::weaken $self;	1817	Scalar::Util::weaken $self;
623		1818
624	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1819	$self->{_rw} = AE::io $self->{fh}, 0, sub {
625	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1820	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
626	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1821	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
627		1822
628	if ($len > 0) {	1823	if ($len > 0) {
629	$self->{filter_r}	1824	$self->{_activity} = $self->{_ractivity} = AE::now;
630	? $self->{filter_r}->($self, $rbuf)	1825
		1826	if ($self->{tls}) {
		1827	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1828
		1829	&_dotls ($self);
		1830	} else {
631	: $self->_drain_rbuf;	1831	$self->_drain_rbuf;
		1832	}
		1833
		1834	if ($len == $self->{read_size}) {
		1835	$self->{read_size} *= 2;
		1836	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		1837	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		1838	}
632		1839
633	} elsif (defined $len) {	1840	} elsif (defined $len) {
634	delete $self->{rw};	1841	delete $self->{_rw};
635	$self->{eof} = 1;	1842	$self->{_eof} = 1;
636	$self->_drain_rbuf;	1843	$self->_drain_rbuf;
637		1844
638	} elsif ($! != EAGAIN && $! != EINTR) {	1845	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
639	return $self->error;	1846	return $self->_error ($!, 1);
640	}	1847	}
641	});	1848	};
642	}	1849	}
643	}	1850	}
644		1851
		1852	our $ERROR_SYSCALL;
		1853	our $ERROR_WANT_READ;
		1854
		1855	sub _tls_error {
		1856	my ($self, $err) = @_;
		1857
		1858	return $self->_error ($!, 1)
		1859	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1860
		1861	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1862
		1863	# reduce error string to look less scary
		1864	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1865
		1866	if ($self->{_on_starttls}) {
		1867	(delete $self->{_on_starttls})->($self, undef, $err);
		1868	&_freetls;
		1869	} else {
		1870	&_freetls;
		1871	$self->_error (Errno::EPROTO, 1, $err);
		1872	}
		1873	}
		1874
		1875	# poll the write BIO and send the data if applicable
		1876	# also decode read data if possible
		1877	# this is basiclaly our TLS state machine
		1878	# more efficient implementations are possible with openssl,
		1879	# but not with the buggy and incomplete Net::SSLeay.
645	sub _dotls {	1880	sub _dotls {
646	my ($self) = @_;	1881	my ($self) = @_;
647		1882
		1883	my $tmp;
		1884
648	if (length $self->{tls_wbuf}) {	1885	if (length $self->{_tls_wbuf}) {
649	my $len = Net::SSLeay::write ($self->{tls}, $self->{tls_wbuf});	1886	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
650	substr $self->{tls_wbuf}, 0, $len, "" if $len > 0;	1887	substr $self->{_tls_wbuf}, 0, $tmp, "";
651	}	1888	}
652		1889
		1890	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1891	return $self->_tls_error ($tmp)
		1892	if $tmp != $ERROR_WANT_READ
		1893	&& ($tmp != $ERROR_SYSCALL || $!);
		1894	}
		1895
653	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{tls_wbio}))) {	1896	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1897	unless (length $tmp) {
		1898	$self->{_on_starttls}
		1899	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1900	&_freetls;
		1901
		1902	if ($self->{on_stoptls}) {
		1903	$self->{on_stoptls}($self);
		1904	return;
		1905	} else {
		1906	# let's treat SSL-eof as we treat normal EOF
		1907	delete $self->{_rw};
		1908	$self->{_eof} = 1;
		1909	}
		1910	}
		1911
		1912	$self->{_tls_rbuf} .= $tmp;
		1913	$self->_drain_rbuf;
		1914	$self->{tls} or return; # tls session might have gone away in callback
		1915	}
		1916
		1917	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1918	return $self->_tls_error ($tmp)
		1919	if $tmp != $ERROR_WANT_READ
		1920	&& ($tmp != $ERROR_SYSCALL || $!);
		1921
		1922	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
654	$self->{wbuf} .= $buf;	1923	$self->{wbuf} .= $tmp;
655	$self->_drain_wbuf;	1924	$self->_drain_wbuf;
		1925	$self->{tls} or return; # tls session might have gone away in callback
656	}	1926	}
657		1927
658	if (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {	1928	$self->{_on_starttls}
659	$self->{rbuf} .= $buf;	1929	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
660	$self->_drain_rbuf;	1930	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
661	} elsif (	1931	}
662	(my $err = Net::SSLeay::get_error ($self->{tls}, -1))	1932
		1933	=item $handle->starttls ($tls[, $tls_ctx])
		1934
		1935	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1936	object is created, you can also do that at a later time by calling
		1937	C<starttls>.
		1938
		1939	Starting TLS is currently an asynchronous operation - when you push some
		1940	write data and then call C<< ->starttls >> then TLS negotiation will start
		1941	immediately, after which the queued write data is then sent.
		1942
		1943	The first argument is the same as the C<tls> constructor argument (either
		1944	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1945
		1946	The second argument is the optional C<AnyEvent::TLS> object that is used
		1947	when AnyEvent::Handle has to create its own TLS connection object, or
		1948	a hash reference with C<< key => value >> pairs that will be used to
		1949	construct a new context.
		1950
		1951	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1952	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1953	changed to your liking. Note that the handshake might have already started
		1954	when this function returns.
		1955
		1956	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1957	handshakes on the same stream. It is best to not attempt to use the
		1958	stream after stopping TLS.
		1959
		1960	This method may invoke callbacks (and therefore the handle might be
		1961	destroyed after it returns).
		1962
		1963	=cut
		1964
		1965	our %TLS_CACHE; #TODO not yet documented, should we?
		1966
		1967	sub starttls {
		1968	my ($self, $tls, $ctx) = @_;
		1969
		1970	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1971	if $self->{tls};
		1972
		1973	$self->{tls} = $tls;
		1974	$self->{tls_ctx} = $ctx if @_ > 2;
		1975
		1976	return unless $self->{fh};
		1977
		1978	require Net::SSLeay;
		1979
		1980	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
663	!= Net::SSLeay::ERROR_WANT_READ ()	1981	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
664	) {	1982
665	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {	1983	$tls = delete $self->{tls};
666	$self->error;	1984	$ctx = $self->{tls_ctx};
667	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {	1985
668	$! = &Errno::EIO;	1986	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
669	$self->error;	1987
		1988	if ("HASH" eq ref $ctx) {
		1989	require AnyEvent::TLS;
		1990
		1991	if ($ctx->{cache}) {
		1992	my $key = $ctx+0;
		1993	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1994	} else {
		1995	$ctx = new AnyEvent::TLS %$ctx;
670	}	1996	}
671		1997	}
672	# all others are fine for our purposes
673	}	1998
674	}	1999	$self->{tls_ctx} = $ctx || TLS_CTX ();
		2000	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
675		2001
676	# TODO: maybe document...	2002	# basically, this is deep magic (because SSL_read should have the same issues)
677	sub starttls {	2003	# but the openssl maintainers basically said: "trust us, it just works".
678	my ($self, $ssl, $ctx) = @_;	2004	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
679		2005	# and mismaintained ssleay-module doesn't even offer them).
680	if ($ssl eq "accept") {	2006	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
681	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
682	Net::SSLeay::set_accept_state ($ssl);
683	} elsif ($ssl eq "connect") {
684	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
685	Net::SSLeay::set_connect_state ($ssl);
686	}	2007	#
		2008	# in short: this is a mess.
		2009	#
		2010	# note that we do not try to keep the length constant between writes as we are required to do.
		2011	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		2012	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		2013	# have identity issues in that area.
		2014	# Net::SSLeay::CTX_set_mode ($ssl,
		2015	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		2016	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		2017	Net::SSLeay::CTX_set_mode ($tls, 1|2);
687		2018
688	$self->{tls} = $ssl;
689
690	$self->{tls_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2019	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
691	$self->{tls_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2020	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
692		2021
		2022	Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
		2023	$self->{rbuf} = "";
		2024
693	Net::SSLeay::set_bio ($ssl, $self->{tls_rbio}, $self->{tls_wbio});	2025	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
694		2026
695	$self->{filter_w} = sub {	2027	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
696	$_[0]{tls_wbuf} .= ${$_[1]};	2028	if $self->{on_starttls};
		2029
		2030	&_dotls; # need to trigger the initial handshake
		2031	$self->start_read; # make sure we actually do read
		2032	}
		2033
		2034	=item $handle->stoptls
		2035
		2036	Shuts down the SSL connection - this makes a proper EOF handshake by
		2037	sending a close notify to the other side, but since OpenSSL doesn't
		2038	support non-blocking shut downs, it is not guaranteed that you can re-use
		2039	the stream afterwards.
		2040
		2041	This method may invoke callbacks (and therefore the handle might be
		2042	destroyed after it returns).
		2043
		2044	=cut
		2045
		2046	sub stoptls {
		2047	my ($self) = @_;
		2048
		2049	if ($self->{tls} && $self->{fh}) {
		2050	Net::SSLeay::shutdown ($self->{tls});
		2051
697	&_dotls;	2052	&_dotls;
		2053
		2054	# # we don't give a shit. no, we do, but we can't. no...#d#
		2055	# # we, we... have to use openssl :/#d#
		2056	# &_freetls;#d#
		2057	}
		2058	}
		2059
		2060	sub _freetls {
		2061	my ($self) = @_;
		2062
		2063	return unless $self->{tls};
		2064
		2065	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2066	if $self->{tls} > 0;
		2067
		2068	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		2069	}
		2070
		2071	=item $handle->resettls
		2072
		2073	This rarely-used method simply resets and TLS state on the handle, usually
		2074	causing data loss.
		2075
		2076	One case where it may be useful is when you want to skip over the data in
		2077	the stream but you are not interested in interpreting it, so data loss is
		2078	no concern.
		2079
		2080	=cut
		2081
		2082	*resettls = \&_freetls;
		2083
		2084	sub DESTROY {
		2085	my ($self) = @_;
		2086
		2087	&_freetls;
		2088
		2089	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		2090
		2091	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2092	my $fh = delete $self->{fh};
		2093	my $wbuf = delete $self->{wbuf};
		2094
		2095	my @linger;
		2096
		2097	push @linger, AE::io $fh, 1, sub {
		2098	my $len = syswrite $fh, $wbuf, length $wbuf;
		2099
		2100	if ($len > 0) {
		2101	substr $wbuf, 0, $len, "";
		2102	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
		2103	@linger = (); # end
		2104	}
		2105	};
		2106	push @linger, AE::timer $linger, 0, sub {
		2107	@linger = ();
		2108	};
		2109	}
		2110	}
		2111
		2112	=item $handle->destroy
		2113
		2114	Shuts down the handle object as much as possible - this call ensures that
		2115	no further callbacks will be invoked and as many resources as possible
		2116	will be freed. Any method you will call on the handle object after
		2117	destroying it in this way will be silently ignored (and it will return the
		2118	empty list).
		2119
		2120	Normally, you can just "forget" any references to an AnyEvent::Handle
		2121	object and it will simply shut down. This works in fatal error and EOF
		2122	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2123	callback, so when you want to destroy the AnyEvent::Handle object from
		2124	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2125	that case.
		2126
		2127	Destroying the handle object in this way has the advantage that callbacks
		2128	will be removed as well, so if those are the only reference holders (as
		2129	is common), then one doesn't need to do anything special to break any
		2130	reference cycles.
		2131
		2132	The handle might still linger in the background and write out remaining
		2133	data, as specified by the C<linger> option, however.
		2134
		2135	=cut
		2136
		2137	sub destroy {
		2138	my ($self) = @_;
		2139
		2140	$self->DESTROY;
		2141	%$self = ();
		2142	bless $self, "AnyEvent::Handle::destroyed";
		2143	}
		2144
		2145	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2146	#nop
		2147	}
		2148
		2149	=item $handle->destroyed
		2150
		2151	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2152	->destroy >>, true otherwise.
		2153
		2154	Can be useful to decide whether the handle is still valid after some
		2155	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2156	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2157	can destroy the handle, so work can be avoided by checking sometimes:
		2158
		2159	$hdl->starttls ("accept");
		2160	return if $hdl->destroyed;
		2161	$hdl->push_write (...
		2162
		2163	Note that the call to C<push_write> will silently be ignored if the handle
		2164	has been destroyed, so often you can just ignore the possibility of the
		2165	handle being destroyed.
		2166
		2167	=cut
		2168
		2169	sub destroyed { 0 }
		2170	sub AnyEvent::Handle::destroyed::destroyed { 1 }
		2171
		2172	=item AnyEvent::Handle::TLS_CTX
		2173
		2174	This function creates and returns the AnyEvent::TLS object used by default
		2175	for TLS mode.
		2176
		2177	The context is created by calling L<AnyEvent::TLS> without any arguments.
		2178
		2179	=cut
		2180
		2181	our $TLS_CTX;
		2182
		2183	sub TLS_CTX() {
		2184	$TLS_CTX ||= do {
		2185	require AnyEvent::TLS;
		2186
		2187	new AnyEvent::TLS
		2188	}
		2189	}
		2190
		2191	=back
		2192
		2193
		2194	=head1 NONFREQUENTLY ASKED QUESTIONS
		2195
		2196	=over 4
		2197
		2198	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2199	still get further invocations!
		2200
		2201	That's because AnyEvent::Handle keeps a reference to itself when handling
		2202	read or write callbacks.
		2203
		2204	It is only safe to "forget" the reference inside EOF or error callbacks,
		2205	from within all other callbacks, you need to explicitly call the C<<
		2206	->destroy >> method.
		2207
		2208	=item Why is my C<on_eof> callback never called?
		2209
		2210	Probably because your C<on_error> callback is being called instead: When
		2211	you have outstanding requests in your read queue, then an EOF is
		2212	considered an error as you clearly expected some data.
		2213
		2214	To avoid this, make sure you have an empty read queue whenever your handle
		2215	is supposed to be "idle" (i.e. connection closes are O.K.). You can set
		2216	an C<on_read> handler that simply pushes the first read requests in the
		2217	queue.
		2218
		2219	See also the next question, which explains this in a bit more detail.
		2220
		2221	=item How can I serve requests in a loop?
		2222
		2223	Most protocols consist of some setup phase (authentication for example)
		2224	followed by a request handling phase, where the server waits for requests
		2225	and handles them, in a loop.
		2226
		2227	There are two important variants: The first (traditional, better) variant
		2228	handles requests until the server gets some QUIT command, causing it to
		2229	close the connection first (highly desirable for a busy TCP server). A
		2230	client dropping the connection is an error, which means this variant can
		2231	detect an unexpected detection close.
		2232
		2233	To handle this case, always make sure you have a on-empty read queue, by
		2234	pushing the "read request start" handler on it:
		2235
		2236	# we assume a request starts with a single line
		2237	my @start_request; @start_request = (line => sub {
		2238	my ($hdl, $line) = @_;
		2239
		2240	... handle request
		2241
		2242	# push next request read, possibly from a nested callback
		2243	$hdl->push_read (@start_request);
		2244	});
		2245
		2246	# auth done, now go into request handling loop
		2247	# now push the first @start_request
		2248	$hdl->push_read (@start_request);
		2249
		2250	By always having an outstanding C<push_read>, the handle always expects
		2251	some data and raises the C<EPIPE> error when the connction is dropped
		2252	unexpectedly.
		2253
		2254	The second variant is a protocol where the client can drop the connection
		2255	at any time. For TCP, this means that the server machine may run out of
		2256	sockets easier, and in general, it means you cannot distinguish a protocl
		2257	failure/client crash from a normal connection close. Nevertheless, these
		2258	kinds of protocols are common (and sometimes even the best solution to the
		2259	problem).
		2260
		2261	Having an outstanding read request at all times is possible if you ignore
		2262	C<EPIPE> errors, but this doesn't help with when the client drops the
		2263	connection during a request, which would still be an error.
		2264
		2265	A better solution is to push the initial request read in an C<on_read>
		2266	callback. This avoids an error, as when the server doesn't expect data
		2267	(i.e. is idly waiting for the next request, an EOF will not raise an
		2268	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2269	and simpler:
		2270
		2271	# auth done, now go into request handling loop
		2272	$hdl->on_read (sub {
		2273	my ($hdl) = @_;
		2274
		2275	# called each time we receive data but the read queue is empty
		2276	# simply start read the request
		2277
		2278	$hdl->push_read (line => sub {
		2279	my ($hdl, $line) = @_;
		2280
		2281	... handle request
		2282
		2283	# do nothing special when the request has been handled, just
		2284	# let the request queue go empty.
		2285	});
		2286	});
		2287
		2288	=item I get different callback invocations in TLS mode/Why can't I pause
		2289	reading?
		2290
		2291	Unlike, say, TCP, TLS connections do not consist of two independent
		2292	communication channels, one for each direction. Or put differently, the
		2293	read and write directions are not independent of each other: you cannot
		2294	write data unless you are also prepared to read, and vice versa.
		2295
		2296	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2297	callback invocations when you are not expecting any read data - the reason
		2298	is that AnyEvent::Handle always reads in TLS mode.
		2299
		2300	During the connection, you have to make sure that you always have a
		2301	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2302	connection (or when you no longer want to use it) you can call the
		2303	C<destroy> method.
		2304
		2305	=item How do I read data until the other side closes the connection?
		2306
		2307	If you just want to read your data into a perl scalar, the easiest way
		2308	to achieve this is by setting an C<on_read> callback that does nothing,
		2309	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2310	will be in C<$_[0]{rbuf}>:
		2311
		2312	$handle->on_read (sub { });
		2313	$handle->on_eof (undef);
		2314	$handle->on_error (sub {
		2315	my $data = delete $_[0]{rbuf};
		2316	});
		2317
		2318	Note that this example removes the C<rbuf> member from the handle object,
		2319	which is not normally allowed by the API. It is expressly permitted in
		2320	this case only, as the handle object needs to be destroyed afterwards.
		2321
		2322	The reason to use C<on_error> is that TCP connections, due to latencies
		2323	and packets loss, might get closed quite violently with an error, when in
		2324	fact all data has been received.
		2325
		2326	It is usually better to use acknowledgements when transferring data,
		2327	to make sure the other side hasn't just died and you got the data
		2328	intact. This is also one reason why so many internet protocols have an
		2329	explicit QUIT command.
		2330
		2331	=item I don't want to destroy the handle too early - how do I wait until
		2332	all data has been written?
		2333
		2334	After writing your last bits of data, set the C<on_drain> callback
		2335	and destroy the handle in there - with the default setting of
		2336	C<low_water_mark> this will be called precisely when all data has been
		2337	written to the socket:
		2338
		2339	$handle->push_write (...);
		2340	$handle->on_drain (sub {
		2341	AE::log debug => "all data submitted to the kernel\n";
		2342	undef $handle;
		2343	});
		2344
		2345	If you just want to queue some data and then signal EOF to the other side,
		2346	consider using C<< ->push_shutdown >> instead.
		2347
		2348	=item I want to contact a TLS/SSL server, I don't care about security.
		2349
		2350	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2351	connect to it and then create the AnyEvent::Handle with the C<tls>
		2352	parameter:
		2353
		2354	tcp_connect $host, $port, sub {
		2355	my ($fh) = @_;
		2356
		2357	my $handle = new AnyEvent::Handle
		2358	fh => $fh,
		2359	tls => "connect",
		2360	on_error => sub { ... };
		2361
		2362	$handle->push_write (...);
698	};	2363	};
699	$self->{filter_r} = sub {
700	Net::SSLeay::BIO_write ($_[0]{tls_rbio}, ${$_[1]});
701	&_dotls;
702	};
703	}
704		2364
705	sub DESTROY {	2365	=item I want to contact a TLS/SSL server, I do care about security.
706	my $self = shift;
707		2366
708	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	2367	Then you should additionally enable certificate verification, including
709	}	2368	peername verification, if the protocol you use supports it (see
		2369	L<AnyEvent::TLS>, C<verify_peername>).
710		2370
711	=item AnyEvent::Handle::TLS_CTX	2371	E.g. for HTTPS:
712		2372
713	This function creates and returns the Net::SSLeay::CTX object used by	2373	tcp_connect $host, $port, sub {
714	default for TLS mode.	2374	my ($fh) = @_;
715		2375
716	The context is created like this:	2376	my $handle = new AnyEvent::Handle
		2377	fh => $fh,
		2378	peername => $host,
		2379	tls => "connect",
		2380	tls_ctx => { verify => 1, verify_peername => "https" },
		2381	...
717		2382
718	Net::SSLeay::load_error_strings;	2383	Note that you must specify the hostname you connected to (or whatever
719	Net::SSLeay::SSLeay_add_ssl_algorithms;	2384	"peername" the protocol needs) as the C<peername> argument, otherwise no
720	Net::SSLeay::randomize;	2385	peername verification will be done.
721		2386
722	my $CTX = Net::SSLeay::CTX_new;	2387	The above will use the system-dependent default set of trusted CA
		2388	certificates. If you want to check against a specific CA, add the
		2389	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
723		2390
724	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL	2391	tls_ctx => {
		2392	verify => 1,
		2393	verify_peername => "https",
		2394	ca_file => "my-ca-cert.pem",
		2395	},
725		2396
726	=cut	2397	=item I want to create a TLS/SSL server, how do I do that?
727		2398
728	our $TLS_CTX;	2399	Well, you first need to get a server certificate and key. You have
		2400	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2401	self-signed certificate (cheap. check the search engine of your choice,
		2402	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2403	nice program for that purpose).
729		2404
730	sub TLS_CTX() {	2405	Then create a file with your private key (in PEM format, see
731	$TLS_CTX || do {	2406	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
732	require Net::SSLeay;	2407	file should then look like this:
733		2408
734	Net::SSLeay::load_error_strings ();	2409	-----BEGIN RSA PRIVATE KEY-----
735	Net::SSLeay::SSLeay_add_ssl_algorithms ();	2410	...header data
736	Net::SSLeay::randomize ();	2411	... lots of base64'y-stuff
		2412	-----END RSA PRIVATE KEY-----
737		2413
738	$TLS_CTX = Net::SSLeay::CTX_new ();	2414	-----BEGIN CERTIFICATE-----
		2415	... lots of base64'y-stuff
		2416	-----END CERTIFICATE-----
739		2417
740	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());	2418	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2419	specify this file as C<cert_file>:
741		2420
742	$TLS_CTX	2421	tcp_server undef, $port, sub {
743	}	2422	my ($fh) = @_;
744	}	2423
		2424	my $handle = new AnyEvent::Handle
		2425	fh => $fh,
		2426	tls => "accept",
		2427	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2428	...
		2429
		2430	When you have intermediate CA certificates that your clients might not
		2431	know about, just append them to the C<cert_file>.
745		2432
746	=back	2433	=back
747		2434
		2435	=head1 SUBCLASSING AnyEvent::Handle
		2436
		2437	In many cases, you might want to subclass AnyEvent::Handle.
		2438
		2439	To make this easier, a given version of AnyEvent::Handle uses these
		2440	conventions:
		2441
		2442	=over 4
		2443
		2444	=item * all constructor arguments become object members.
		2445
		2446	At least initially, when you pass a C<tls>-argument to the constructor it
		2447	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2448	mutated later on (for example C<tls> will hold the TLS connection object).
		2449
		2450	=item * other object member names are prefixed with an C<_>.
		2451
		2452	All object members not explicitly documented (internal use) are prefixed
		2453	with an underscore character, so the remaining non-C<_>-namespace is free
		2454	for use for subclasses.
		2455
		2456	=item * all members not documented here and not prefixed with an underscore
		2457	are free to use in subclasses.
		2458
		2459	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2460	member variables, but that's just life. At least it is documented.
		2461
		2462	=back
		2463
748	=head1 AUTHOR	2464	=head1 AUTHOR
749		2465
750	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	2466	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
751		2467
752	=cut	2468	=cut
753		2469
754	1; # End of AnyEvent::Handle	2470	1
		2471

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