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Revision 1.31 by root, Sun May 25 00:08:49 2008 UTC vs.
Revision 1.195 by root, Sat Jun 5 09:08:14 2010 UTC

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict;
5
6	use AnyEvent ();
7	use AnyEvent::Util ();
8	use Scalar::Util ();
9	use Carp ();
10	use Fcntl ();
11	use Errno qw/EAGAIN EINTR/;
12
13	=head1 NAME	1	=head1 NAME
14		2
15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent	3	AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
16
17	=cut
18
19	our $VERSION = '0.04';
20		4
21	=head1 SYNOPSIS	5	=head1 SYNOPSIS
22		6
23	use AnyEvent;	7	use AnyEvent;
24	use AnyEvent::Handle;	8	use AnyEvent::Handle;
25		9
26	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
27		11
28	my $handle =	12	my $hdl; $hdl = new AnyEvent::Handle
29	AnyEvent::Handle->new (
30	fh => \*STDIN,	13	fh => \*STDIN,
31	on_eof => sub {	14	on_error => sub {
32	$cv->broadcast;	15	my ($hdl, $fatal, $msg) = @_;
33	},	16	warn "got error $msg\n";
		17	$hdl->destroy;
		18	$cv->send;
34	);	19	};
35		20
36	# send some request line	21	# send some request line
37	$handle->push_write ("getinfo\015\012");	22	$hdl->push_write ("getinfo\015\012");
38		23
39	# read the response line	24	# read the response line
40	$handle->push_read (line => sub {	25	$hdl->push_read (line => sub {
41	my ($handle, $line) = @_;	26	my ($hdl, $line) = @_;
42	warn "read line <$line>\n";	27	warn "got line <$line>\n";
43	$cv->send;	28	$cv->send;
44	});	29	});
45		30
46	$cv->recv;	31	$cv->recv;
47		32
48	=head1 DESCRIPTION	33	=head1 DESCRIPTION
49		34
50	This module is a helper module to make it easier to do event-based I/O on	35	This module is a helper module to make it easier to do event-based I/O on
51	filehandles. For utility functions for doing non-blocking connects and accepts	36	stream-based filehandles (sockets, pipes or other stream things).
52	on sockets see L<AnyEvent::Util>.	37
		38	The L<AnyEvent::Intro> tutorial contains some well-documented
		39	AnyEvent::Handle examples.
53		40
54	In the following, when the documentation refers to of "bytes" then this	41	In the following, when the documentation refers to of "bytes" then this
55	means characters. As sysread and syswrite are used for all I/O, their	42	means characters. As sysread and syswrite are used for all I/O, their
56	treatment of characters applies to this module as well.	43	treatment of characters applies to this module as well.
57		44
		45	At the very minimum, you should specify C<fh> or C<connect>, and the
		46	C<on_error> callback.
		47
58	All callbacks will be invoked with the handle object as their first	48	All callbacks will be invoked with the handle object as their first
59	argument.	49	argument.
60		50
		51	=cut
		52
		53	package AnyEvent::Handle;
		54
		55	use Scalar::Util ();
		56	use List::Util ();
		57	use Carp ();
		58	use Errno qw(EAGAIN EINTR);
		59
		60	use AnyEvent (); BEGIN { AnyEvent::common_sense }
		61	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		62
		63	our $VERSION = $AnyEvent::VERSION;
		64
		65	sub _load_func($) {
		66	my $func = $_[0];
		67
		68	unless (defined &$func) {
		69	my $pkg = $func;
		70	do {
		71	$pkg =~ s/::[^:]+$//
		72	or return;
		73	eval "require $pkg";
		74	} until defined &$func;
		75	}
		76
		77	\&$func
		78	}
		79
61	=head1 METHODS	80	=head1 METHODS
62		81
63	=over 4	82	=over 4
64		83
65	=item B<new (%args)>	84	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
66		85
67	The constructor supports these arguments (all as key => value pairs).	86	The constructor supports these arguments (all as C<< key => value >> pairs).
68		87
69	=over 4	88	=over 4
70		89
71	=item fh => $filehandle [MANDATORY]	90	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
72		91
73	The filehandle this L<AnyEvent::Handle> object will operate on.	92	The filehandle this L<AnyEvent::Handle> object will operate on.
74
75	NOTE: The filehandle will be set to non-blocking (using	93	NOTE: The filehandle will be set to non-blocking mode (using
76	AnyEvent::Util::fh_nonblocking).	94	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		95	that mode.
77		96
78	=item on_eof => $cb->($self)	97	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
79		98
80	Set the callback to be called on EOF.	99	Try to connect to the specified host and service (port), using
		100	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		101	default C<peername>.
81		102
82	While not mandatory, it is highly recommended to set an eof callback,	103	You have to specify either this parameter, or C<fh>, above.
83	otherwise you might end up with a closed socket while you are still
84	waiting for data.
85		104
		105	It is possible to push requests on the read and write queues, and modify
		106	properties of the stream, even while AnyEvent::Handle is connecting.
		107
		108	When this parameter is specified, then the C<on_prepare>,
		109	C<on_connect_error> and C<on_connect> callbacks will be called under the
		110	appropriate circumstances:
		111
		112	=over 4
		113
86	=item on_error => $cb->($self)	114	=item on_prepare => $cb->($handle)
87		115
		116	This (rarely used) callback is called before a new connection is
		117	attempted, but after the file handle has been created. It could be used to
		118	prepare the file handle with parameters required for the actual connect
		119	(as opposed to settings that can be changed when the connection is already
		120	established).
		121
		122	The return value of this callback should be the connect timeout value in
		123	seconds (or C<0>, or C<undef>, or the empty list, to indicate the default
		124	timeout is to be used).
		125
		126	=item on_connect => $cb->($handle, $host, $port, $retry->())
		127
		128	This callback is called when a connection has been successfully established.
		129
		130	The actual numeric host and port (the socket peername) are passed as
		131	parameters, together with a retry callback.
		132
		133	When, for some reason, the handle is not acceptable, then calling
		134	C<$retry> will continue with the next connection target (in case of
		135	multi-homed hosts or SRV records there can be multiple connection
		136	endpoints). At the time it is called the read and write queues, eof
		137	status, tls status and similar properties of the handle will have been
		138	reset.
		139
		140	In most cases, ignoring the C<$retry> parameter is the way to go.
		141
		142	=item on_connect_error => $cb->($handle, $message)
		143
		144	This callback is called when the connection could not be
		145	established. C<$!> will contain the relevant error code, and C<$message> a
		146	message describing it (usually the same as C<"$!">).
		147
		148	If this callback isn't specified, then C<on_error> will be called with a
		149	fatal error instead.
		150
		151	=back
		152
		153	=item on_error => $cb->($handle, $fatal, $message)
		154
88	This is the fatal error callback, that is called when, well, a fatal error	155	This is the error callback, which is called when, well, some error
89	occurs, such as not being able to resolve the hostname, failure to connect	156	occured, such as not being able to resolve the hostname, failure to
90	or a read error.	157	connect or a read error.
91		158
92	The object will not be in a usable state when this callback has been	159	Some errors are fatal (which is indicated by C<$fatal> being true). On
93	called.	160	fatal errors the handle object will be destroyed (by a call to C<< ->
		161	destroy >>) after invoking the error callback (which means you are free to
		162	examine the handle object). Examples of fatal errors are an EOF condition
		163	with active (but unsatisifable) read watchers (C<EPIPE>) or I/O errors. In
		164	cases where the other side can close the connection at their will it is
		165	often easiest to not report C<EPIPE> errors in this callback.
		166
		167	AnyEvent::Handle tries to find an appropriate error code for you to check
		168	against, but in some cases (TLS errors), this does not work well. It is
		169	recommended to always output the C<$message> argument in human-readable
		170	error messages (it's usually the same as C<"$!">).
		171
		172	Non-fatal errors can be retried by simply returning, but it is recommended
		173	to simply ignore this parameter and instead abondon the handle object
		174	when this callback is invoked. Examples of non-fatal errors are timeouts
		175	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
94		176
95	On callback entrance, the value of C<$!> contains the operating system	177	On callback entrance, the value of C<$!> contains the operating system
96	error (or C<ENOSPC>, C<EPIPE> or C<EBADMSG>).	178	error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		179	C<EPROTO>).
97		180
98	While not mandatory, it is I<highly> recommended to set this callback, as	181	While not mandatory, it is I<highly> recommended to set this callback, as
99	you will not be notified of errors otherwise. The default simply calls	182	you will not be notified of errors otherwise. The default simply calls
100	die.	183	C<croak>.
101		184
102	=item on_read => $cb->($self)	185	=item on_read => $cb->($handle)
103		186
104	This sets the default read callback, which is called when data arrives	187	This sets the default read callback, which is called when data arrives
105	and no read request is in the queue.	188	and no read request is in the queue (unlike read queue callbacks, this
		189	callback will only be called when at least one octet of data is in the
		190	read buffer).
106		191
107	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	192	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
108	method or access the C<$self->{rbuf}> member directly.	193	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		194	must not enlarge or modify the read buffer, you can only remove data at
		195	the beginning from it.
109		196
110	When an EOF condition is detected then AnyEvent::Handle will first try to	197	When an EOF condition is detected then AnyEvent::Handle will first try to
111	feed all the remaining data to the queued callbacks and C<on_read> before	198	feed all the remaining data to the queued callbacks and C<on_read> before
112	calling the C<on_eof> callback. If no progress can be made, then a fatal	199	calling the C<on_eof> callback. If no progress can be made, then a fatal
113	error will be raised (with C<$!> set to C<EPIPE>).	200	error will be raised (with C<$!> set to C<EPIPE>).
114		201
		202	Note that, unlike requests in the read queue, an C<on_read> callback
		203	doesn't mean you I<require> some data: if there is an EOF and there
		204	are outstanding read requests then an error will be flagged. With an
		205	C<on_read> callback, the C<on_eof> callback will be invoked.
		206
		207	=item on_eof => $cb->($handle)
		208
		209	Set the callback to be called when an end-of-file condition is detected,
		210	i.e. in the case of a socket, when the other side has closed the
		211	connection cleanly, and there are no outstanding read requests in the
		212	queue (if there are read requests, then an EOF counts as an unexpected
		213	connection close and will be flagged as an error).
		214
		215	For sockets, this just means that the other side has stopped sending data,
		216	you can still try to write data, and, in fact, one can return from the EOF
		217	callback and continue writing data, as only the read part has been shut
		218	down.
		219
		220	If an EOF condition has been detected but no C<on_eof> callback has been
		221	set, then a fatal error will be raised with C<$!> set to <0>.
		222
115	=item on_drain => $cb->()	223	=item on_drain => $cb->($handle)
116		224
117	This sets the callback that is called when the write buffer becomes empty	225	This sets the callback that is called when the write buffer becomes empty
118	(or when the callback is set and the buffer is empty already).	226	(or when the callback is set and the buffer is empty already).
119		227
120	To append to the write buffer, use the C<< ->push_write >> method.	228	To append to the write buffer, use the C<< ->push_write >> method.
121		229
		230	This callback is useful when you don't want to put all of your write data
		231	into the queue at once, for example, when you want to write the contents
		232	of some file to the socket you might not want to read the whole file into
		233	memory and push it into the queue, but instead only read more data from
		234	the file when the write queue becomes empty.
		235
		236	=item timeout => $fractional_seconds
		237
		238	=item rtimeout => $fractional_seconds
		239
		240	=item wtimeout => $fractional_seconds
		241
		242	If non-zero, then these enables an "inactivity" timeout: whenever this
		243	many seconds pass without a successful read or write on the underlying
		244	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
		245	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		246	error will be raised).
		247
		248	There are three variants of the timeouts that work fully independent
		249	of each other, for both read and write, just read, and just write:
		250	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		251	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		252	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		253
		254	Note that timeout processing is also active when you currently do not have
		255	any outstanding read or write requests: If you plan to keep the connection
		256	idle then you should disable the timout temporarily or ignore the timeout
		257	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		258	restart the timeout.
		259
		260	Zero (the default) disables this timeout.
		261
		262	=item on_timeout => $cb->($handle)
		263
		264	Called whenever the inactivity timeout passes. If you return from this
		265	callback, then the timeout will be reset as if some activity had happened,
		266	so this condition is not fatal in any way.
		267
122	=item rbuf_max => <bytes>	268	=item rbuf_max => <bytes>
123		269
124	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	270	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
125	when the read buffer ever (strictly) exceeds this size. This is useful to	271	when the read buffer ever (strictly) exceeds this size. This is useful to
126	avoid denial-of-service attacks.	272	avoid some forms of denial-of-service attacks.
127		273
128	For example, a server accepting connections from untrusted sources should	274	For example, a server accepting connections from untrusted sources should
129	be configured to accept only so-and-so much data that it cannot act on	275	be configured to accept only so-and-so much data that it cannot act on
130	(for example, when expecting a line, an attacker could send an unlimited	276	(for example, when expecting a line, an attacker could send an unlimited
131	amount of data without a callback ever being called as long as the line	277	amount of data without a callback ever being called as long as the line
132	isn't finished).	278	isn't finished).
133		279
		280	=item autocork => <boolean>
		281
		282	When disabled (the default), then C<push_write> will try to immediately
		283	write the data to the handle, if possible. This avoids having to register
		284	a write watcher and wait for the next event loop iteration, but can
		285	be inefficient if you write multiple small chunks (on the wire, this
		286	disadvantage is usually avoided by your kernel's nagle algorithm, see
		287	C<no_delay>, but this option can save costly syscalls).
		288
		289	When enabled, then writes will always be queued till the next event loop
		290	iteration. This is efficient when you do many small writes per iteration,
		291	but less efficient when you do a single write only per iteration (or when
		292	the write buffer often is full). It also increases write latency.
		293
		294	=item no_delay => <boolean>
		295
		296	When doing small writes on sockets, your operating system kernel might
		297	wait a bit for more data before actually sending it out. This is called
		298	the Nagle algorithm, and usually it is beneficial.
		299
		300	In some situations you want as low a delay as possible, which can be
		301	accomplishd by setting this option to a true value.
		302
		303	The default is your opertaing system's default behaviour (most likely
		304	enabled), this option explicitly enables or disables it, if possible.
		305
		306	=item keepalive => <boolean>
		307
		308	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		309	normally, TCP connections have no time-out once established, so TCP
		310	connections, once established, can stay alive forever even when the other
		311	side has long gone. TCP keepalives are a cheap way to take down long-lived
		312	TCP connections whent he other side becomes unreachable. While the default
		313	is OS-dependent, TCP keepalives usually kick in after around two hours,
		314	and, if the other side doesn't reply, take down the TCP connection some 10
		315	to 15 minutes later.
		316
		317	It is harmless to specify this option for file handles that do not support
		318	keepalives, and enabling it on connections that are potentially long-lived
		319	is usually a good idea.
		320
		321	=item oobinline => <boolean>
		322
		323	BSD majorly fucked up the implementation of TCP urgent data. The result
		324	is that almost no OS implements TCP according to the specs, and every OS
		325	implements it slightly differently.
		326
		327	If you want to handle TCP urgent data, then setting this flag (the default
		328	is enabled) gives you the most portable way of getting urgent data, by
		329	putting it into the stream.
		330
		331	Since BSD emulation of OOB data on top of TCP's urgent data can have
		332	security implications, AnyEvent::Handle sets this flag automatically
		333	unless explicitly specified. Note that setting this flag after
		334	establishing a connection I<may> be a bit too late (data loss could
		335	already have occured on BSD systems), but at least it will protect you
		336	from most attacks.
		337
134	=item read_size => <bytes>	338	=item read_size => <bytes>
135		339
136	The default read block size (the amount of bytes this module will try to read	340	The default read block size (the amount of bytes this module will
137	on each [loop iteration). Default: C<4096>.	341	try to read during each loop iteration, which affects memory
		342	requirements). Default: C<8192>.
138		343
139	=item low_water_mark => <bytes>	344	=item low_water_mark => <bytes>
140		345
141	Sets the amount of bytes (default: C<0>) that make up an "empty" write	346	Sets the amount of bytes (default: C<0>) that make up an "empty" write
142	buffer: If the write reaches this size or gets even samller it is	347	buffer: If the write reaches this size or gets even samller it is
143	considered empty.	348	considered empty.
144		349
		350	Sometimes it can be beneficial (for performance reasons) to add data to
		351	the write buffer before it is fully drained, but this is a rare case, as
		352	the operating system kernel usually buffers data as well, so the default
		353	is good in almost all cases.
		354
		355	=item linger => <seconds>
		356
		357	If non-zero (default: C<3600>), then the destructor of the
		358	AnyEvent::Handle object will check whether there is still outstanding
		359	write data and will install a watcher that will write this data to the
		360	socket. No errors will be reported (this mostly matches how the operating
		361	system treats outstanding data at socket close time).
		362
		363	This will not work for partial TLS data that could not be encoded
		364	yet. This data will be lost. Calling the C<stoptls> method in time might
		365	help.
		366
		367	=item peername => $string
		368
		369	A string used to identify the remote site - usually the DNS hostname
		370	(I<not> IDN!) used to create the connection, rarely the IP address.
		371
		372	Apart from being useful in error messages, this string is also used in TLS
		373	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		374	verification will be skipped when C<peername> is not specified or
		375	C<undef>.
		376
145	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	377	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
146		378
147	When this parameter is given, it enables TLS (SSL) mode, that means it	379	When this parameter is given, it enables TLS (SSL) mode, that means
148	will start making tls handshake and will transparently encrypt/decrypt	380	AnyEvent will start a TLS handshake as soon as the connection has been
149	data.	381	established and will transparently encrypt/decrypt data afterwards.
		382
		383	All TLS protocol errors will be signalled as C<EPROTO>, with an
		384	appropriate error message.
150		385
151	TLS mode requires Net::SSLeay to be installed (it will be loaded	386	TLS mode requires Net::SSLeay to be installed (it will be loaded
152	automatically when you try to create a TLS handle).	387	automatically when you try to create a TLS handle): this module doesn't
		388	have a dependency on that module, so if your module requires it, you have
		389	to add the dependency yourself.
153		390
154	For the TLS server side, use C<accept>, and for the TLS client side of a	391	Unlike TCP, TLS has a server and client side: for the TLS server side, use
155	connection, use C<connect> mode.	392	C<accept>, and for the TLS client side of a connection, use C<connect>
		393	mode.
156		394
157	You can also provide your own TLS connection object, but you have	395	You can also provide your own TLS connection object, but you have
158	to make sure that you call either C<Net::SSLeay::set_connect_state>	396	to make sure that you call either C<Net::SSLeay::set_connect_state>
159	or C<Net::SSLeay::set_accept_state> on it before you pass it to	397	or C<Net::SSLeay::set_accept_state> on it before you pass it to
160	AnyEvent::Handle.	398	AnyEvent::Handle. Also, this module will take ownership of this connection
		399	object.
161		400
		401	At some future point, AnyEvent::Handle might switch to another TLS
		402	implementation, then the option to use your own session object will go
		403	away.
		404
		405	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		406	passing in the wrong integer will lead to certain crash. This most often
		407	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		408	segmentation fault.
		409
162	See the C<starttls> method if you need to start TLs negotiation later.	410	See the C<< ->starttls >> method for when need to start TLS negotiation later.
163		411
164	=item tls_ctx => $ssl_ctx	412	=item tls_ctx => $anyevent_tls
165		413
166	Use the given Net::SSLeay::CTX object to create the new TLS connection	414	Use the given C<AnyEvent::TLS> object to create the new TLS connection
167	(unless a connection object was specified directly). If this parameter is	415	(unless a connection object was specified directly). If this parameter is
168	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	416	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
169		417
		418	Instead of an object, you can also specify a hash reference with C<< key
		419	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		420	new TLS context object.
		421
		422	=item on_starttls => $cb->($handle, $success[, $error_message])
		423
		424	This callback will be invoked when the TLS/SSL handshake has finished. If
		425	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		426	(C<on_stoptls> will not be called in this case).
		427
		428	The session in C<< $handle->{tls} >> can still be examined in this
		429	callback, even when the handshake was not successful.
		430
		431	TLS handshake failures will not cause C<on_error> to be invoked when this
		432	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		433
		434	Without this callback, handshake failures lead to C<on_error> being
		435	called, as normal.
		436
		437	Note that you cannot call C<starttls> right again in this callback. If you
		438	need to do that, start an zero-second timer instead whose callback can
		439	then call C<< ->starttls >> again.
		440
		441	=item on_stoptls => $cb->($handle)
		442
		443	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		444	set, then it will be invoked after freeing the TLS session. If it is not,
		445	then a TLS shutdown condition will be treated like a normal EOF condition
		446	on the handle.
		447
		448	The session in C<< $handle->{tls} >> can still be examined in this
		449	callback.
		450
		451	This callback will only be called on TLS shutdowns, not when the
		452	underlying handle signals EOF.
		453
		454	=item json => JSON or JSON::XS object
		455
		456	This is the json coder object used by the C<json> read and write types.
		457
		458	If you don't supply it, then AnyEvent::Handle will create and use a
		459	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		460	texts.
		461
		462	Note that you are responsible to depend on the JSON module if you want to
		463	use this functionality, as AnyEvent does not have a dependency itself.
		464
170	=back	465	=back
171		466
172	=cut	467	=cut
173		468
174	sub new {	469	sub new {
175	my $class = shift;	470	my $class = shift;
176
177	my $self = bless { @_ }, $class;	471	my $self = bless { @_ }, $class;
178		472
179	$self->{fh} or Carp::croak "mandatory argument fh is missing";	473	if ($self->{fh}) {
		474	$self->_start;
		475	return unless $self->{fh}; # could be gone by now
		476
		477	} elsif ($self->{connect}) {
		478	require AnyEvent::Socket;
		479
		480	$self->{peername} = $self->{connect}[0]
		481	unless exists $self->{peername};
		482
		483	$self->{_skip_drain_rbuf} = 1;
		484
		485	{
		486	Scalar::Util::weaken (my $self = $self);
		487
		488	$self->{_connect} =
		489	AnyEvent::Socket::tcp_connect (
		490	$self->{connect}[0],
		491	$self->{connect}[1],
		492	sub {
		493	my ($fh, $host, $port, $retry) = @_;
		494
		495	if ($fh) {
		496	$self->{fh} = $fh;
		497
		498	delete $self->{_skip_drain_rbuf};
		499	$self->_start;
		500
		501	$self->{on_connect}
		502	and $self->{on_connect}($self, $host, $port, sub {
		503	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		504	$self->{_skip_drain_rbuf} = 1;
		505	&$retry;
		506	});
		507
		508	} else {
		509	if ($self->{on_connect_error}) {
		510	$self->{on_connect_error}($self, "$!");
		511	$self->destroy;
		512	} else {
		513	$self->_error ($!, 1);
		514	}
		515	}
		516	},
		517	sub {
		518	local $self->{fh} = $_[0];
		519
		520	$self->{on_prepare}
		521	? $self->{on_prepare}->($self)
		522	: ()
		523	}
		524	);
		525	}
		526
		527	} else {
		528	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		529	}
		530
		531	$self
		532	}
		533
		534	sub _start {
		535	my ($self) = @_;
		536
		537	# too many clueless people try to use udp and similar sockets
		538	# with AnyEvent::Handle, do them a favour.
		539	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		540	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		541	if Socket::SOCK_STREAM != (unpack "I", $type) && defined $type;
180		542
181	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	543	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
182		544
183	if ($self->{tls}) {	545	$self->{_activity} =
184	require Net::SSLeay;	546	$self->{_ractivity} =
		547	$self->{_wactivity} = AE::now;
		548
		549	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		550	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		551	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		552
		553	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		554	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		555
		556	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		557
185	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	558	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
186	}	559	if $self->{tls};
187		560
188	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
189	$self->on_error (delete $self->{on_error}) if $self->{on_error};
190	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	561	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};
191	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
192		562
193	$self->start_read;	563	$self->start_read
		564	if $self->{on_read} || @{ $self->{_queue} };
194		565
195	$self	566	$self->_drain_wbuf;
196	}	567	}
197		568
198	sub _shutdown {
199	my ($self) = @_;
200
201	delete $self->{rw};
202	delete $self->{ww};
203	delete $self->{fh};
204	}
205
206	sub error {	569	sub _error {
207	my ($self) = @_;	570	my ($self, $errno, $fatal, $message) = @_;
208		571
209	{	572	$! = $errno;
210	local $!;	573	$message ||= "$!";
211	$self->_shutdown;
212	}
213		574
214	if ($self->{on_error}) {	575	if ($self->{on_error}) {
215	$self->{on_error}($self);	576	$self->{on_error}($self, $fatal, $message);
216	} else {	577	$self->destroy if $fatal;
		578	} elsif ($self->{fh} || $self->{connect}) {
		579	$self->destroy;
217	Carp::croak "AnyEvent::Handle uncaught fatal error: $!";	580	Carp::croak "AnyEvent::Handle uncaught error: $message";
218	}	581	}
219	}	582	}
220		583
221	=item $fh = $handle->fh	584	=item $fh = $handle->fh
222		585
223	This method returns the file handle of the L<AnyEvent::Handle> object.	586	This method returns the file handle used to create the L<AnyEvent::Handle> object.
224		587
225	=cut	588	=cut
226		589
227	sub fh { $_[0]->{fh} }	590	sub fh { $_[0]{fh} }
228		591
229	=item $handle->on_error ($cb)	592	=item $handle->on_error ($cb)
230		593
231	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	594	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
232		595
…		…
244		607
245	sub on_eof {	608	sub on_eof {
246	$_[0]{on_eof} = $_[1];	609	$_[0]{on_eof} = $_[1];
247	}	610	}
248		611
		612	=item $handle->on_timeout ($cb)
		613
		614	=item $handle->on_rtimeout ($cb)
		615
		616	=item $handle->on_wtimeout ($cb)
		617
		618	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		619	callback, or disables the callback (but not the timeout) if C<$cb> =
		620	C<undef>. See the C<timeout> constructor argument and method.
		621
		622	=cut
		623
		624	# see below
		625
		626	=item $handle->autocork ($boolean)
		627
		628	Enables or disables the current autocork behaviour (see C<autocork>
		629	constructor argument). Changes will only take effect on the next write.
		630
		631	=cut
		632
		633	sub autocork {
		634	$_[0]{autocork} = $_[1];
		635	}
		636
		637	=item $handle->no_delay ($boolean)
		638
		639	Enables or disables the C<no_delay> setting (see constructor argument of
		640	the same name for details).
		641
		642	=cut
		643
		644	sub no_delay {
		645	$_[0]{no_delay} = $_[1];
		646
		647	eval {
		648	local $SIG{__DIE__};
		649	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		650	if $_[0]{fh};
		651	};
		652	}
		653
		654	=item $handle->keepalive ($boolean)
		655
		656	Enables or disables the C<keepalive> setting (see constructor argument of
		657	the same name for details).
		658
		659	=cut
		660
		661	sub keepalive {
		662	$_[0]{keepalive} = $_[1];
		663
		664	eval {
		665	local $SIG{__DIE__};
		666	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		667	if $_[0]{fh};
		668	};
		669	}
		670
		671	=item $handle->oobinline ($boolean)
		672
		673	Enables or disables the C<oobinline> setting (see constructor argument of
		674	the same name for details).
		675
		676	=cut
		677
		678	sub oobinline {
		679	$_[0]{oobinline} = $_[1];
		680
		681	eval {
		682	local $SIG{__DIE__};
		683	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		684	if $_[0]{fh};
		685	};
		686	}
		687
		688	=item $handle->keepalive ($boolean)
		689
		690	Enables or disables the C<keepalive> setting (see constructor argument of
		691	the same name for details).
		692
		693	=cut
		694
		695	sub keepalive {
		696	$_[0]{keepalive} = $_[1];
		697
		698	eval {
		699	local $SIG{__DIE__};
		700	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		701	if $_[0]{fh};
		702	};
		703	}
		704
		705	=item $handle->on_starttls ($cb)
		706
		707	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		708
		709	=cut
		710
		711	sub on_starttls {
		712	$_[0]{on_starttls} = $_[1];
		713	}
		714
		715	=item $handle->on_stoptls ($cb)
		716
		717	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		718
		719	=cut
		720
		721	sub on_stoptls {
		722	$_[0]{on_stoptls} = $_[1];
		723	}
		724
		725	=item $handle->rbuf_max ($max_octets)
		726
		727	Configures the C<rbuf_max> setting (C<undef> disables it).
		728
		729	=cut
		730
		731	sub rbuf_max {
		732	$_[0]{rbuf_max} = $_[1];
		733	}
		734
		735	#############################################################################
		736
		737	=item $handle->timeout ($seconds)
		738
		739	=item $handle->rtimeout ($seconds)
		740
		741	=item $handle->wtimeout ($seconds)
		742
		743	Configures (or disables) the inactivity timeout.
		744
		745	=item $handle->timeout_reset
		746
		747	=item $handle->rtimeout_reset
		748
		749	=item $handle->wtimeout_reset
		750
		751	Reset the activity timeout, as if data was received or sent.
		752
		753	These methods are cheap to call.
		754
		755	=cut
		756
		757	for my $dir ("", "r", "w") {
		758	my $timeout = "${dir}timeout";
		759	my $tw = "_${dir}tw";
		760	my $on_timeout = "on_${dir}timeout";
		761	my $activity = "_${dir}activity";
		762	my $cb;
		763
		764	*$on_timeout = sub {
		765	$_[0]{$on_timeout} = $_[1];
		766	};
		767
		768	*$timeout = sub {
		769	my ($self, $new_value) = @_;
		770
		771	$self->{$timeout} = $new_value;
		772	delete $self->{$tw}; &$cb;
		773	};
		774
		775	*{"${dir}timeout_reset"} = sub {
		776	$_[0]{$activity} = AE::now;
		777	};
		778
		779	# main workhorse:
		780	# reset the timeout watcher, as neccessary
		781	# also check for time-outs
		782	$cb = sub {
		783	my ($self) = @_;
		784
		785	if ($self->{$timeout} && $self->{fh}) {
		786	my $NOW = AE::now;
		787
		788	# when would the timeout trigger?
		789	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		790
		791	# now or in the past already?
		792	if ($after <= 0) {
		793	$self->{$activity} = $NOW;
		794
		795	if ($self->{$on_timeout}) {
		796	$self->{$on_timeout}($self);
		797	} else {
		798	$self->_error (Errno::ETIMEDOUT);
		799	}
		800
		801	# callback could have changed timeout value, optimise
		802	return unless $self->{$timeout};
		803
		804	# calculate new after
		805	$after = $self->{$timeout};
		806	}
		807
		808	Scalar::Util::weaken $self;
		809	return unless $self; # ->error could have destroyed $self
		810
		811	$self->{$tw} ||= AE::timer $after, 0, sub {
		812	delete $self->{$tw};
		813	$cb->($self);
		814	};
		815	} else {
		816	delete $self->{$tw};
		817	}
		818	}
		819	}
		820
249	#############################################################################	821	#############################################################################
250		822
251	=back	823	=back
252		824
253	=head2 WRITE QUEUE	825	=head2 WRITE QUEUE
…		…
266	=item $handle->on_drain ($cb)	838	=item $handle->on_drain ($cb)
267		839
268	Sets the C<on_drain> callback or clears it (see the description of	840	Sets the C<on_drain> callback or clears it (see the description of
269	C<on_drain> in the constructor).	841	C<on_drain> in the constructor).
270		842
		843	This method may invoke callbacks (and therefore the handle might be
		844	destroyed after it returns).
		845
271	=cut	846	=cut
272		847
273	sub on_drain {	848	sub on_drain {
274	my ($self, $cb) = @_;	849	my ($self, $cb) = @_;
275		850
276	$self->{on_drain} = $cb;	851	$self->{on_drain} = $cb;
277		852
278	$cb->($self)	853	$cb->($self)
279	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	854	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
280	}	855	}
281		856
282	=item $handle->push_write ($data)	857	=item $handle->push_write ($data)
283		858
284	Queues the given scalar to be written. You can push as much data as you	859	Queues the given scalar to be written. You can push as much data as you
285	want (only limited by the available memory), as C<AnyEvent::Handle>	860	want (only limited by the available memory), as C<AnyEvent::Handle>
286	buffers it independently of the kernel.	861	buffers it independently of the kernel.
287		862
		863	This method may invoke callbacks (and therefore the handle might be
		864	destroyed after it returns).
		865
288	=cut	866	=cut
289		867
290	sub _drain_wbuf {	868	sub _drain_wbuf {
291	my ($self) = @_;	869	my ($self) = @_;
292		870
293	if (!$self->{ww} && length $self->{wbuf}) {	871	if (!$self->{_ww} && length $self->{wbuf}) {
		872
294	Scalar::Util::weaken $self;	873	Scalar::Util::weaken $self;
		874
295	my $cb = sub {	875	my $cb = sub {
296	my $len = syswrite $self->{fh}, $self->{wbuf};	876	my $len = syswrite $self->{fh}, $self->{wbuf};
297		877
298	if ($len >= 0) {	878	if (defined $len) {
299	substr $self->{wbuf}, 0, $len, "";	879	substr $self->{wbuf}, 0, $len, "";
300		880
		881	$self->{_activity} = $self->{_wactivity} = AE::now;
		882
301	$self->{on_drain}($self)	883	$self->{on_drain}($self)
302	if $self->{low_water_mark} >= length $self->{wbuf}	884	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
303	&& $self->{on_drain};	885	&& $self->{on_drain};
304		886
305	delete $self->{ww} unless length $self->{wbuf};	887	delete $self->{_ww} unless length $self->{wbuf};
306	} elsif ($! != EAGAIN && $! != EINTR) {	888	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
307	$self->error;	889	$self->_error ($!, 1);
308	}	890	}
309	};	891	};
310		892
311	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	893	# try to write data immediately
		894	$cb->() unless $self->{autocork};
312		895
313	$cb->($self);	896	# if still data left in wbuf, we need to poll
		897	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		898	if length $self->{wbuf};
314	};	899	};
315	}	900	}
316		901
317	our %WH;	902	our %WH;
318		903
		904	# deprecated
319	sub register_write_type($$) {	905	sub register_write_type($$) {
320	$WH{$_[0]} = $_[1];	906	$WH{$_[0]} = $_[1];
321	}	907	}
322		908
323	sub push_write {	909	sub push_write {
324	my $self = shift;	910	my $self = shift;
325		911
326	if (@_ > 1) {	912	if (@_ > 1) {
327	my $type = shift;	913	my $type = shift;
328		914
		915	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
329	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	916	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
330	->($self, @_);	917	->($self, @_);
331	}	918	}
332		919
		920	# we downgrade here to avoid hard-to-track-down bugs,
		921	# and diagnose the problem earlier and better.
		922
333	if ($self->{filter_w}) {	923	if ($self->{tls}) {
334	$self->{filter_w}->($self, \$_[0]);	924	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		925	&_dotls ($self) if $self->{fh};
335	} else {	926	} else {
336	$self->{wbuf} .= $_[0];	927	utf8::downgrade $self->{wbuf} .= $_[0];
337	$self->_drain_wbuf;	928	$self->_drain_wbuf if $self->{fh};
338	}	929	}
339	}	930	}
340		931
341	=item $handle->push_write (type => @args)	932	=item $handle->push_write (type => @args)
342		933
343	=item $handle->unshift_write (type => @args)
344
345	Instead of formatting your data yourself, you can also let this module do	934	Instead of formatting your data yourself, you can also let this module
346	the job by specifying a type and type-specific arguments.	935	do the job by specifying a type and type-specific arguments. You
		936	can also specify the (fully qualified) name of a package, in which
		937	case AnyEvent tries to load the package and then expects to find the
		938	C<anyevent_read_type> function inside (see "custom write types", below).
347		939
348	Predefined types are (if you have ideas for additional types, feel free to	940	Predefined types are (if you have ideas for additional types, feel free to
349	drop by and tell us):	941	drop by and tell us):
350		942
351	=over 4	943	=over 4
…		…
353	=item netstring => $string	945	=item netstring => $string
354		946
355	Formats the given value as netstring	947	Formats the given value as netstring
356	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).	948	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
357		949
358	=back
359
360	=cut	950	=cut
361		951
362	register_write_type netstring => sub {	952	register_write_type netstring => sub {
363	my ($self, $string) = @_;	953	my ($self, $string) = @_;
364		954
365	sprintf "%d:%s,", (length $string), $string	955	(length $string) . ":$string,"
366	};	956	};
367		957
368	=item AnyEvent::Handle::register_write_type type => $coderef->($self, @args)	958	=item packstring => $format, $data
369		959
370	This function (not method) lets you add your own types to C<push_write>.	960	An octet string prefixed with an encoded length. The encoding C<$format>
		961	uses the same format as a Perl C<pack> format, but must specify a single
		962	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		963	optional C<!>, C<< < >> or C<< > >> modifier).
		964
		965	=cut
		966
		967	register_write_type packstring => sub {
		968	my ($self, $format, $string) = @_;
		969
		970	pack "$format/a*", $string
		971	};
		972
		973	=item json => $array_or_hashref
		974
		975	Encodes the given hash or array reference into a JSON object. Unless you
		976	provide your own JSON object, this means it will be encoded to JSON text
		977	in UTF-8.
		978
		979	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		980	one end of a handle and read them at the other end without using any
		981	additional framing.
		982
		983	The generated JSON text is guaranteed not to contain any newlines: While
		984	this module doesn't need delimiters after or between JSON texts to be
		985	able to read them, many other languages depend on that.
		986
		987	A simple RPC protocol that interoperates easily with others is to send
		988	JSON arrays (or objects, although arrays are usually the better choice as
		989	they mimic how function argument passing works) and a newline after each
		990	JSON text:
		991
		992	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		993	$handle->push_write ("\012");
		994
		995	An AnyEvent::Handle receiver would simply use the C<json> read type and
		996	rely on the fact that the newline will be skipped as leading whitespace:
		997
		998	$handle->push_read (json => sub { my $array = $_[1]; ... });
		999
		1000	Other languages could read single lines terminated by a newline and pass
		1001	this line into their JSON decoder of choice.
		1002
		1003	=cut
		1004
		1005	sub json_coder() {
		1006	eval { require JSON::XS; JSON::XS->new->utf8 }
		1007	|| do { require JSON; JSON->new->utf8 }
		1008	}
		1009
		1010	register_write_type json => sub {
		1011	my ($self, $ref) = @_;
		1012
		1013	my $json = $self->{json} ||= json_coder;
		1014
		1015	$json->encode ($ref)
		1016	};
		1017
		1018	=item storable => $reference
		1019
		1020	Freezes the given reference using L<Storable> and writes it to the
		1021	handle. Uses the C<nfreeze> format.
		1022
		1023	=cut
		1024
		1025	register_write_type storable => sub {
		1026	my ($self, $ref) = @_;
		1027
		1028	require Storable;
		1029
		1030	pack "w/a*", Storable::nfreeze ($ref)
		1031	};
		1032
		1033	=back
		1034
		1035	=item $handle->push_shutdown
		1036
		1037	Sometimes you know you want to close the socket after writing your data
		1038	before it was actually written. One way to do that is to replace your
		1039	C<on_drain> handler by a callback that shuts down the socket (and set
		1040	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1041	replaces the C<on_drain> callback with:
		1042
		1043	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		1044
		1045	This simply shuts down the write side and signals an EOF condition to the
		1046	the peer.
		1047
		1048	You can rely on the normal read queue and C<on_eof> handling
		1049	afterwards. This is the cleanest way to close a connection.
		1050
		1051	This method may invoke callbacks (and therefore the handle might be
		1052	destroyed after it returns).
		1053
		1054	=cut
		1055
		1056	sub push_shutdown {
		1057	my ($self) = @_;
		1058
		1059	delete $self->{low_water_mark};
		1060	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1061	}
		1062
		1063	=item custom write types - Package::anyevent_write_type $handle, @args
		1064
		1065	Instead of one of the predefined types, you can also specify the name of
		1066	a package. AnyEvent will try to load the package and then expects to find
		1067	a function named C<anyevent_write_type> inside. If it isn't found, it
		1068	progressively tries to load the parent package until it either finds the
		1069	function (good) or runs out of packages (bad).
		1070
371	Whenever the given C<type> is used, C<push_write> will invoke the code	1071	Whenever the given C<type> is used, C<push_write> will the function with
372	reference with the handle object and the remaining arguments.	1072	the handle object and the remaining arguments.
373		1073
374	The code reference is supposed to return a single octet string that will	1074	The function is supposed to return a single octet string that will be
375	be appended to the write buffer.	1075	appended to the write buffer, so you cna mentally treat this function as a
		1076	"arguments to on-the-wire-format" converter.
376		1077
377	Note that this is a function, and all types registered this way will be	1078	Example: implement a custom write type C<join> that joins the remaining
378	global, so try to use unique names.	1079	arguments using the first one.
		1080
		1081	$handle->push_write (My::Type => " ", 1,2,3);
		1082
		1083	# uses the following package, which can be defined in the "My::Type" or in
		1084	# the "My" modules to be auto-loaded, or just about anywhere when the
		1085	# My::Type::anyevent_write_type is defined before invoking it.
		1086
		1087	package My::Type;
		1088
		1089	sub anyevent_write_type {
		1090	my ($handle, $delim, @args) = @_;
		1091
		1092	join $delim, @args
		1093	}
379		1094
380	=cut	1095	=cut
381		1096
382	#############################################################################	1097	#############################################################################
383		1098
…		…
392	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1107	ways, the "simple" way, using only C<on_read> and the "complex" way, using
393	a queue.	1108	a queue.
394		1109
395	In the simple case, you just install an C<on_read> callback and whenever	1110	In the simple case, you just install an C<on_read> callback and whenever
396	new data arrives, it will be called. You can then remove some data (if	1111	new data arrives, it will be called. You can then remove some data (if
397	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1112	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
398	or not.	1113	leave the data there if you want to accumulate more (e.g. when only a
		1114	partial message has been received so far).
399		1115
400	In the more complex case, you want to queue multiple callbacks. In this	1116	In the more complex case, you want to queue multiple callbacks. In this
401	case, AnyEvent::Handle will call the first queued callback each time new	1117	case, AnyEvent::Handle will call the first queued callback each time new
402	data arrives and removes it when it has done its job (see C<push_read>,	1118	data arrives (also the first time it is queued) and removes it when it has
403	below).	1119	done its job (see C<push_read>, below).
404		1120
405	This way you can, for example, push three line-reads, followed by reading	1121	This way you can, for example, push three line-reads, followed by reading
406	a chunk of data, and AnyEvent::Handle will execute them in order.	1122	a chunk of data, and AnyEvent::Handle will execute them in order.
407		1123
408	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1124	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
409	the specified number of bytes which give an XML datagram.	1125	the specified number of bytes which give an XML datagram.
410		1126
411	# in the default state, expect some header bytes	1127	# in the default state, expect some header bytes
412	$handle->on_read (sub {	1128	$handle->on_read (sub {
413	# some data is here, now queue the length-header-read (4 octets)	1129	# some data is here, now queue the length-header-read (4 octets)
414	shift->unshift_read_chunk (4, sub {	1130	shift->unshift_read (chunk => 4, sub {
415	# header arrived, decode	1131	# header arrived, decode
416	my $len = unpack "N", $_[1];	1132	my $len = unpack "N", $_[1];
417		1133
418	# now read the payload	1134	# now read the payload
419	shift->unshift_read_chunk ($len, sub {	1135	shift->unshift_read (chunk => $len, sub {
420	my $xml = $_[1];	1136	my $xml = $_[1];
421	# handle xml	1137	# handle xml
422	});	1138	});
423	});	1139	});
424	});	1140	});
425		1141
426	Example 2: Implement a client for a protocol that replies either with	1142	Example 2: Implement a client for a protocol that replies either with "OK"
427	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1143	and another line or "ERROR" for the first request that is sent, and 64
428	second request. Due tot he availability of a full queue, we can just	1144	bytes for the second request. Due to the availability of a queue, we can
429	pipeline sending both requests and manipulate the queue as necessary in	1145	just pipeline sending both requests and manipulate the queue as necessary
430	the callbacks:	1146	in the callbacks.
431		1147
432	# request one	1148	When the first callback is called and sees an "OK" response, it will
		1149	C<unshift> another line-read. This line-read will be queued I<before> the
		1150	64-byte chunk callback.
		1151
		1152	# request one, returns either "OK + extra line" or "ERROR"
433	$handle->push_write ("request 1\015\012");	1153	$handle->push_write ("request 1\015\012");
434		1154
435	# we expect "ERROR" or "OK" as response, so push a line read	1155	# we expect "ERROR" or "OK" as response, so push a line read
436	$handle->push_read_line (sub {	1156	$handle->push_read (line => sub {
437	# if we got an "OK", we have to _prepend_ another line,	1157	# if we got an "OK", we have to _prepend_ another line,
438	# so it will be read before the second request reads its 64 bytes	1158	# so it will be read before the second request reads its 64 bytes
439	# which are already in the queue when this callback is called	1159	# which are already in the queue when this callback is called
440	# we don't do this in case we got an error	1160	# we don't do this in case we got an error
441	if ($_[1] eq "OK") {	1161	if ($_[1] eq "OK") {
442	$_[0]->unshift_read_line (sub {	1162	$_[0]->unshift_read (line => sub {
443	my $response = $_[1];	1163	my $response = $_[1];
444	...	1164	...
445	});	1165	});
446	}	1166	}
447	});	1167	});
448		1168
449	# request two	1169	# request two, simply returns 64 octets
450	$handle->push_write ("request 2\015\012");	1170	$handle->push_write ("request 2\015\012");
451		1171
452	# simply read 64 bytes, always	1172	# simply read 64 bytes, always
453	$handle->push_read_chunk (64, sub {	1173	$handle->push_read (chunk => 64, sub {
454	my $response = $_[1];	1174	my $response = $_[1];
455	...	1175	...
456	});	1176	});
457		1177
458	=over 4	1178	=over 4
459		1179
460	=cut	1180	=cut
461		1181
462	sub _drain_rbuf {	1182	sub _drain_rbuf {
463	my ($self) = @_;	1183	my ($self) = @_;
		1184
		1185	# avoid recursion
		1186	return if $self->{_skip_drain_rbuf};
		1187	local $self->{_skip_drain_rbuf} = 1;
		1188
		1189	while () {
		1190	# we need to use a separate tls read buffer, as we must not receive data while
		1191	# we are draining the buffer, and this can only happen with TLS.
		1192	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1193	if exists $self->{_tls_rbuf};
		1194
		1195	my $len = length $self->{rbuf};
		1196
		1197	if (my $cb = shift @{ $self->{_queue} }) {
		1198	unless ($cb->($self)) {
		1199	# no progress can be made
		1200	# (not enough data and no data forthcoming)
		1201	$self->_error (Errno::EPIPE, 1), return
		1202	if $self->{_eof};
		1203
		1204	unshift @{ $self->{_queue} }, $cb;
		1205	last;
		1206	}
		1207	} elsif ($self->{on_read}) {
		1208	last unless $len;
		1209
		1210	$self->{on_read}($self);
		1211
		1212	if (
		1213	$len == length $self->{rbuf} # if no data has been consumed
		1214	&& !@{ $self->{_queue} } # and the queue is still empty
		1215	&& $self->{on_read} # but we still have on_read
		1216	) {
		1217	# no further data will arrive
		1218	# so no progress can be made
		1219	$self->_error (Errno::EPIPE, 1), return
		1220	if $self->{_eof};
		1221
		1222	last; # more data might arrive
		1223	}
		1224	} else {
		1225	# read side becomes idle
		1226	delete $self->{_rw} unless $self->{tls};
		1227	last;
		1228	}
		1229	}
		1230
		1231	if ($self->{_eof}) {
		1232	$self->{on_eof}
		1233	? $self->{on_eof}($self)
		1234	: $self->_error (0, 1, "Unexpected end-of-file");
		1235
		1236	return;
		1237	}
464		1238
465	if (	1239	if (
466	defined $self->{rbuf_max}	1240	defined $self->{rbuf_max}
467	&& $self->{rbuf_max} < length $self->{rbuf}	1241	&& $self->{rbuf_max} < length $self->{rbuf}
468	) {	1242	) {
469	$! = &Errno::ENOSPC; return $self->error;	1243	$self->_error (Errno::ENOSPC, 1), return;
470	}	1244	}
471		1245
472	return if $self->{in_drain};	1246	# may need to restart read watcher
473	local $self->{in_drain} = 1;	1247	unless ($self->{_rw}) {
474		1248	$self->start_read
475	while (my $len = length $self->{rbuf}) {	1249	if $self->{on_read} || @{ $self->{_queue} };
476	no strict 'refs';
477	if (my $cb = shift @{ $self->{queue} }) {
478	unless ($cb->($self)) {
479	if ($self->{eof}) {
480	# no progress can be made (not enough data and no data forthcoming)
481	$! = &Errno::EPIPE; return $self->error;
482	}
483
484	unshift @{ $self->{queue} }, $cb;
485	return;
486	}
487	} elsif ($self->{on_read}) {
488	$self->{on_read}($self);
489
490	if (
491	$self->{eof} # if no further data will arrive
492	&& $len == length $self->{rbuf} # and no data has been consumed
493	&& !@{ $self->{queue} } # and the queue is still empty
494	&& $self->{on_read} # and we still want to read data
495	) {
496	# then no progress can be made
497	$! = &Errno::EPIPE; return $self->error;
498	}
499	} else {
500	# read side becomes idle
501	delete $self->{rw};
502	return;
503	}
504	}
505
506	if ($self->{eof}) {
507	$self->_shutdown;
508	$self->{on_eof}($self)
509	if $self->{on_eof};
510	}	1250	}
511	}	1251	}
512		1252
513	=item $handle->on_read ($cb)	1253	=item $handle->on_read ($cb)
514		1254
515	This replaces the currently set C<on_read> callback, or clears it (when	1255	This replaces the currently set C<on_read> callback, or clears it (when
516	the new callback is C<undef>). See the description of C<on_read> in the	1256	the new callback is C<undef>). See the description of C<on_read> in the
517	constructor.	1257	constructor.
518		1258
		1259	This method may invoke callbacks (and therefore the handle might be
		1260	destroyed after it returns).
		1261
519	=cut	1262	=cut
520		1263
521	sub on_read {	1264	sub on_read {
522	my ($self, $cb) = @_;	1265	my ($self, $cb) = @_;
523		1266
524	$self->{on_read} = $cb;	1267	$self->{on_read} = $cb;
		1268	$self->_drain_rbuf if $cb;
525	}	1269	}
526		1270
527	=item $handle->rbuf	1271	=item $handle->rbuf
528		1272
529	Returns the read buffer (as a modifiable lvalue).	1273	Returns the read buffer (as a modifiable lvalue).
530		1274
531	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1275	You can access the read buffer directly as the C<< ->{rbuf} >>
532	you want.	1276	member, if you want. However, the only operation allowed on the
		1277	read buffer (apart from looking at it) is removing data from its
		1278	beginning. Otherwise modifying or appending to it is not allowed and will
		1279	lead to hard-to-track-down bugs.
533		1280
534	NOTE: The read buffer should only be used or modified if the C<on_read>,	1281	NOTE: The read buffer should only be used or modified if the C<on_read>,
535	C<push_read> or C<unshift_read> methods are used. The other read methods	1282	C<push_read> or C<unshift_read> methods are used. The other read methods
536	automatically manage the read buffer.	1283	automatically manage the read buffer.
537		1284
…		…
558		1305
559	If enough data was available, then the callback must remove all data it is	1306	If enough data was available, then the callback must remove all data it is
560	interested in (which can be none at all) and return a true value. After returning	1307	interested in (which can be none at all) and return a true value. After returning
561	true, it will be removed from the queue.	1308	true, it will be removed from the queue.
562		1309
		1310	These methods may invoke callbacks (and therefore the handle might be
		1311	destroyed after it returns).
		1312
563	=cut	1313	=cut
564		1314
565	our %RH;	1315	our %RH;
566		1316
567	sub register_read_type($$) {	1317	sub register_read_type($$) {
…		…
573	my $cb = pop;	1323	my $cb = pop;
574		1324
575	if (@_) {	1325	if (@_) {
576	my $type = shift;	1326	my $type = shift;
577		1327
		1328	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
578	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	1329	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
579	->($self, $cb, @_);	1330	->($self, $cb, @_);
580	}	1331	}
581		1332
582	push @{ $self->{queue} }, $cb;	1333	push @{ $self->{_queue} }, $cb;
583	$self->_drain_rbuf;	1334	$self->_drain_rbuf;
584	}	1335	}
585		1336
586	sub unshift_read {	1337	sub unshift_read {
587	my $self = shift;	1338	my $self = shift;
…		…
592		1343
593	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")	1344	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
594	->($self, $cb, @_);	1345	->($self, $cb, @_);
595	}	1346	}
596		1347
597
598	unshift @{ $self->{queue} }, $cb;	1348	unshift @{ $self->{_queue} }, $cb;
599	$self->_drain_rbuf;	1349	$self->_drain_rbuf;
600	}	1350	}
601		1351
602	=item $handle->push_read (type => @args, $cb)	1352	=item $handle->push_read (type => @args, $cb)
603		1353
604	=item $handle->unshift_read (type => @args, $cb)	1354	=item $handle->unshift_read (type => @args, $cb)
605		1355
606	Instead of providing a callback that parses the data itself you can chose	1356	Instead of providing a callback that parses the data itself you can chose
607	between a number of predefined parsing formats, for chunks of data, lines	1357	between a number of predefined parsing formats, for chunks of data, lines
608	etc.	1358	etc. You can also specify the (fully qualified) name of a package, in
		1359	which case AnyEvent tries to load the package and then expects to find the
		1360	C<anyevent_read_type> function inside (see "custom read types", below).
609		1361
610	Predefined types are (if you have ideas for additional types, feel free to	1362	Predefined types are (if you have ideas for additional types, feel free to
611	drop by and tell us):	1363	drop by and tell us):
612		1364
613	=over 4	1365	=over 4
614		1366
615	=item chunk => $octets, $cb->($self, $data)	1367	=item chunk => $octets, $cb->($handle, $data)
616		1368
617	Invoke the callback only once C<$octets> bytes have been read. Pass the	1369	Invoke the callback only once C<$octets> bytes have been read. Pass the
618	data read to the callback. The callback will never be called with less	1370	data read to the callback. The callback will never be called with less
619	data.	1371	data.
620		1372
…		…
634	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1386	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
635	1	1387	1
636	}	1388	}
637	};	1389	};
638		1390
639	# compatibility with older API
640	sub push_read_chunk {
641	$_[0]->push_read (chunk => $_[1], $_[2]);
642	}
643
644	sub unshift_read_chunk {
645	$_[0]->unshift_read (chunk => $_[1], $_[2]);
646	}
647
648	=item line => [$eol, ]$cb->($self, $line, $eol)	1391	=item line => [$eol, ]$cb->($handle, $line, $eol)
649		1392
650	The callback will be called only once a full line (including the end of	1393	The callback will be called only once a full line (including the end of
651	line marker, C<$eol>) has been read. This line (excluding the end of line	1394	line marker, C<$eol>) has been read. This line (excluding the end of line
652	marker) will be passed to the callback as second argument (C<$line>), and	1395	marker) will be passed to the callback as second argument (C<$line>), and
653	the end of line marker as the third argument (C<$eol>).	1396	the end of line marker as the third argument (C<$eol>).
…		…
667	=cut	1410	=cut
668		1411
669	register_read_type line => sub {	1412	register_read_type line => sub {
670	my ($self, $cb, $eol) = @_;	1413	my ($self, $cb, $eol) = @_;
671		1414
672	$eol = qr|(\015?\012)| if @_ < 3;	1415	if (@_ < 3) {
		1416	# this is more than twice as fast as the generic code below
		1417	sub {
		1418	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1419
		1420	$cb->($_[0], $1, $2);
		1421	1
		1422	}
		1423	} else {
673	$eol = quotemeta $eol unless ref $eol;	1424	$eol = quotemeta $eol unless ref $eol;
674	$eol = qr|^(.*?)($eol)|s;	1425	$eol = qr|^(.*?)($eol)|s;
		1426
		1427	sub {
		1428	$_[0]{rbuf} =~ s/$eol// or return;
		1429
		1430	$cb->($_[0], $1, $2);
		1431	1
		1432	}
		1433	}
		1434	};
		1435
		1436	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1437
		1438	Makes a regex match against the regex object C<$accept> and returns
		1439	everything up to and including the match.
		1440
		1441	Example: read a single line terminated by '\n'.
		1442
		1443	$handle->push_read (regex => qr<\n>, sub { ... });
		1444
		1445	If C<$reject> is given and not undef, then it determines when the data is
		1446	to be rejected: it is matched against the data when the C<$accept> regex
		1447	does not match and generates an C<EBADMSG> error when it matches. This is
		1448	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1449	receive buffer overflow).
		1450
		1451	Example: expect a single decimal number followed by whitespace, reject
		1452	anything else (not the use of an anchor).
		1453
		1454	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1455
		1456	If C<$skip> is given and not C<undef>, then it will be matched against
		1457	the receive buffer when neither C<$accept> nor C<$reject> match,
		1458	and everything preceding and including the match will be accepted
		1459	unconditionally. This is useful to skip large amounts of data that you
		1460	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1461	have to start matching from the beginning. This is purely an optimisation
		1462	and is usually worth only when you expect more than a few kilobytes.
		1463
		1464	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1465	expect the header to be very large (it isn't in practise, but...), we use
		1466	a skip regex to skip initial portions. The skip regex is tricky in that
		1467	it only accepts something not ending in either \015 or \012, as these are
		1468	required for the accept regex.
		1469
		1470	$handle->push_read (regex =>
		1471	qr<\015\012\015\012>,
		1472	undef, # no reject
		1473	qr<^.*[^\015\012]>,
		1474	sub { ... });
		1475
		1476	=cut
		1477
		1478	register_read_type regex => sub {
		1479	my ($self, $cb, $accept, $reject, $skip) = @_;
		1480
		1481	my $data;
		1482	my $rbuf = \$self->{rbuf};
675		1483
676	sub {	1484	sub {
677	$_[0]{rbuf} =~ s/$eol// or return;	1485	# accept
678		1486	if ($$rbuf =~ $accept) {
679	$cb->($_[0], $1, $2);	1487	$data .= substr $$rbuf, 0, $+[0], "";
		1488	$cb->($self, $data);
		1489	return 1;
		1490	}
680	1	1491
		1492	# reject
		1493	if ($reject && $$rbuf =~ $reject) {
		1494	$self->_error (Errno::EBADMSG);
		1495	}
		1496
		1497	# skip
		1498	if ($skip && $$rbuf =~ $skip) {
		1499	$data .= substr $$rbuf, 0, $+[0], "";
		1500	}
		1501
		1502	()
681	}	1503	}
682	};	1504	};
683		1505
684	# compatibility with older API
685	sub push_read_line {
686	my $self = shift;
687	$self->push_read (line => @_);
688	}
689
690	sub unshift_read_line {
691	my $self = shift;
692	$self->unshift_read (line => @_);
693	}
694
695	=item netstring => $cb->($string)	1506	=item netstring => $cb->($handle, $string)
696		1507
697	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).	1508	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
698		1509
699	Throws an error with C<$!> set to EBADMSG on format violations.	1510	Throws an error with C<$!> set to EBADMSG on format violations.
700		1511
…		…
704	my ($self, $cb) = @_;	1515	my ($self, $cb) = @_;
705		1516
706	sub {	1517	sub {
707	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {	1518	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
708	if ($_[0]{rbuf} =~ /[^0-9]/) {	1519	if ($_[0]{rbuf} =~ /[^0-9]/) {
709	$! = &Errno::EBADMSG;	1520	$self->_error (Errno::EBADMSG);
710	$self->error;
711	}	1521	}
712	return;	1522	return;
713	}	1523	}
714		1524
715	my $len = $1;	1525	my $len = $1;
…		…
718	my $string = $_[1];	1528	my $string = $_[1];
719	$_[0]->unshift_read (chunk => 1, sub {	1529	$_[0]->unshift_read (chunk => 1, sub {
720	if ($_[1] eq ",") {	1530	if ($_[1] eq ",") {
721	$cb->($_[0], $string);	1531	$cb->($_[0], $string);
722	} else {	1532	} else {
723	$! = &Errno::EBADMSG;
724	$self->error;	1533	$self->_error (Errno::EBADMSG);
725	}	1534	}
726	});	1535	});
727	});	1536	});
728		1537
729	1	1538	1
730	}	1539	}
731	};	1540	};
732		1541
		1542	=item packstring => $format, $cb->($handle, $string)
		1543
		1544	An octet string prefixed with an encoded length. The encoding C<$format>
		1545	uses the same format as a Perl C<pack> format, but must specify a single
		1546	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1547	optional C<!>, C<< < >> or C<< > >> modifier).
		1548
		1549	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1550	EPP uses a prefix of C<N> (4 octtes).
		1551
		1552	Example: read a block of data prefixed by its length in BER-encoded
		1553	format (very efficient).
		1554
		1555	$handle->push_read (packstring => "w", sub {
		1556	my ($handle, $data) = @_;
		1557	});
		1558
		1559	=cut
		1560
		1561	register_read_type packstring => sub {
		1562	my ($self, $cb, $format) = @_;
		1563
		1564	sub {
		1565	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1566	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1567	or return;
		1568
		1569	$format = length pack $format, $len;
		1570
		1571	# bypass unshift if we already have the remaining chunk
		1572	if ($format + $len <= length $_[0]{rbuf}) {
		1573	my $data = substr $_[0]{rbuf}, $format, $len;
		1574	substr $_[0]{rbuf}, 0, $format + $len, "";
		1575	$cb->($_[0], $data);
		1576	} else {
		1577	# remove prefix
		1578	substr $_[0]{rbuf}, 0, $format, "";
		1579
		1580	# read remaining chunk
		1581	$_[0]->unshift_read (chunk => $len, $cb);
		1582	}
		1583
		1584	1
		1585	}
		1586	};
		1587
		1588	=item json => $cb->($handle, $hash_or_arrayref)
		1589
		1590	Reads a JSON object or array, decodes it and passes it to the
		1591	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1592
		1593	If a C<json> object was passed to the constructor, then that will be used
		1594	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1595
		1596	This read type uses the incremental parser available with JSON version
		1597	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1598	dependency on your own: this module will load the JSON module, but
		1599	AnyEvent does not depend on it itself.
		1600
		1601	Since JSON texts are fully self-delimiting, the C<json> read and write
		1602	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1603	the C<json> write type description, above, for an actual example.
		1604
		1605	=cut
		1606
		1607	register_read_type json => sub {
		1608	my ($self, $cb) = @_;
		1609
		1610	my $json = $self->{json} ||= json_coder;
		1611
		1612	my $data;
		1613	my $rbuf = \$self->{rbuf};
		1614
		1615	sub {
		1616	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1617
		1618	if ($ref) {
		1619	$self->{rbuf} = $json->incr_text;
		1620	$json->incr_text = "";
		1621	$cb->($self, $ref);
		1622
		1623	1
		1624	} elsif ($@) {
		1625	# error case
		1626	$json->incr_skip;
		1627
		1628	$self->{rbuf} = $json->incr_text;
		1629	$json->incr_text = "";
		1630
		1631	$self->_error (Errno::EBADMSG);
		1632
		1633	()
		1634	} else {
		1635	$self->{rbuf} = "";
		1636
		1637	()
		1638	}
		1639	}
		1640	};
		1641
		1642	=item storable => $cb->($handle, $ref)
		1643
		1644	Deserialises a L<Storable> frozen representation as written by the
		1645	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1646	data).
		1647
		1648	Raises C<EBADMSG> error if the data could not be decoded.
		1649
		1650	=cut
		1651
		1652	register_read_type storable => sub {
		1653	my ($self, $cb) = @_;
		1654
		1655	require Storable;
		1656
		1657	sub {
		1658	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1659	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1660	or return;
		1661
		1662	my $format = length pack "w", $len;
		1663
		1664	# bypass unshift if we already have the remaining chunk
		1665	if ($format + $len <= length $_[0]{rbuf}) {
		1666	my $data = substr $_[0]{rbuf}, $format, $len;
		1667	substr $_[0]{rbuf}, 0, $format + $len, "";
		1668	$cb->($_[0], Storable::thaw ($data));
		1669	} else {
		1670	# remove prefix
		1671	substr $_[0]{rbuf}, 0, $format, "";
		1672
		1673	# read remaining chunk
		1674	$_[0]->unshift_read (chunk => $len, sub {
		1675	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1676	$cb->($_[0], $ref);
		1677	} else {
		1678	$self->_error (Errno::EBADMSG);
		1679	}
		1680	});
		1681	}
		1682
		1683	1
		1684	}
		1685	};
		1686
733	=back	1687	=back
734		1688
735	=item AnyEvent::Handle::register_read_type type => $coderef->($self, $cb, @args)	1689	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
736		1690
737	This function (not method) lets you add your own types to C<push_read>.	1691	Instead of one of the predefined types, you can also specify the name
		1692	of a package. AnyEvent will try to load the package and then expects to
		1693	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1694	progressively tries to load the parent package until it either finds the
		1695	function (good) or runs out of packages (bad).
738		1696
739	Whenever the given C<type> is used, C<push_read> will invoke the code	1697	Whenever this type is used, C<push_read> will invoke the function with the
740	reference with the handle object, the callback and the remaining	1698	handle object, the original callback and the remaining arguments.
741	arguments.
742		1699
743	The code reference is supposed to return a callback (usually a closure)	1700	The function is supposed to return a callback (usually a closure) that
744	that works as a plain read callback (see C<< ->push_read ($cb) >>).	1701	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1702	mentally treat the function as a "configurable read type to read callback"
		1703	converter.
745		1704
746	It should invoke the passed callback when it is done reading (remember to	1705	It should invoke the original callback when it is done reading (remember
747	pass C<$self> as first argument as all other callbacks do that).	1706	to pass C<$handle> as first argument as all other callbacks do that,
		1707	although there is no strict requirement on this).
748		1708
749	Note that this is a function, and all types registered this way will be
750	global, so try to use unique names.
751
752	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,	1709	For examples, see the source of this module (F<perldoc -m
753	search for C<register_read_type>)).	1710	AnyEvent::Handle>, search for C<register_read_type>)).
754		1711
755	=item $handle->stop_read	1712	=item $handle->stop_read
756		1713
757	=item $handle->start_read	1714	=item $handle->start_read
758		1715
759	In rare cases you actually do not want to read anything from the	1716	In rare cases you actually do not want to read anything from the
760	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1717	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
761	any queued callbacks will be executed then. To start reading again, call	1718	any queued callbacks will be executed then. To start reading again, call
762	C<start_read>.	1719	C<start_read>.
763		1720
		1721	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1722	you change the C<on_read> callback or push/unshift a read callback, and it
		1723	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1724	there are any read requests in the queue.
		1725
		1726	These methods will have no effect when in TLS mode (as TLS doesn't support
		1727	half-duplex connections).
		1728
764	=cut	1729	=cut
765		1730
766	sub stop_read {	1731	sub stop_read {
767	my ($self) = @_;	1732	my ($self) = @_;
768		1733
769	delete $self->{rw};	1734	delete $self->{_rw} unless $self->{tls};
770	}	1735	}
771		1736
772	sub start_read {	1737	sub start_read {
773	my ($self) = @_;	1738	my ($self) = @_;
774		1739
775	unless ($self->{rw} || $self->{eof}) {	1740	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
776	Scalar::Util::weaken $self;	1741	Scalar::Util::weaken $self;
777		1742
778	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1743	$self->{_rw} = AE::io $self->{fh}, 0, sub {
779	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1744	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
780	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1745	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
781		1746
782	if ($len > 0) {	1747	if ($len > 0) {
783	$self->{filter_r}	1748	$self->{_activity} = $self->{_ractivity} = AE::now;
784	? $self->{filter_r}->($self, $rbuf)	1749
		1750	if ($self->{tls}) {
		1751	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1752
		1753	&_dotls ($self);
		1754	} else {
785	: $self->_drain_rbuf;	1755	$self->_drain_rbuf;
		1756	}
786		1757
787	} elsif (defined $len) {	1758	} elsif (defined $len) {
788	delete $self->{rw};	1759	delete $self->{_rw};
789	$self->{eof} = 1;	1760	$self->{_eof} = 1;
790	$self->_drain_rbuf;	1761	$self->_drain_rbuf;
791		1762
792	} elsif ($! != EAGAIN && $! != EINTR) {	1763	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
793	return $self->error;	1764	return $self->_error ($!, 1);
794	}	1765	}
795	});	1766	};
796	}	1767	}
797	}	1768	}
798		1769
		1770	our $ERROR_SYSCALL;
		1771	our $ERROR_WANT_READ;
		1772
		1773	sub _tls_error {
		1774	my ($self, $err) = @_;
		1775
		1776	return $self->_error ($!, 1)
		1777	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1778
		1779	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1780
		1781	# reduce error string to look less scary
		1782	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1783
		1784	if ($self->{_on_starttls}) {
		1785	(delete $self->{_on_starttls})->($self, undef, $err);
		1786	&_freetls;
		1787	} else {
		1788	&_freetls;
		1789	$self->_error (Errno::EPROTO, 1, $err);
		1790	}
		1791	}
		1792
		1793	# poll the write BIO and send the data if applicable
		1794	# also decode read data if possible
		1795	# this is basiclaly our TLS state machine
		1796	# more efficient implementations are possible with openssl,
		1797	# but not with the buggy and incomplete Net::SSLeay.
799	sub _dotls {	1798	sub _dotls {
800	my ($self) = @_;	1799	my ($self) = @_;
801		1800
		1801	my $tmp;
		1802
802	if (length $self->{tls_wbuf}) {	1803	if (length $self->{_tls_wbuf}) {
803	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{tls_wbuf})) > 0) {	1804	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
804	substr $self->{tls_wbuf}, 0, $len, "";	1805	substr $self->{_tls_wbuf}, 0, $tmp, "";
805	}	1806	}
806	}
807		1807
		1808	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1809	return $self->_tls_error ($tmp)
		1810	if $tmp != $ERROR_WANT_READ
		1811	&& ($tmp != $ERROR_SYSCALL || $!);
		1812	}
		1813
808	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{tls_wbio}))) {	1814	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1815	unless (length $tmp) {
		1816	$self->{_on_starttls}
		1817	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1818	&_freetls;
		1819
		1820	if ($self->{on_stoptls}) {
		1821	$self->{on_stoptls}($self);
		1822	return;
		1823	} else {
		1824	# let's treat SSL-eof as we treat normal EOF
		1825	delete $self->{_rw};
		1826	$self->{_eof} = 1;
		1827	}
		1828	}
		1829
		1830	$self->{_tls_rbuf} .= $tmp;
		1831	$self->_drain_rbuf;
		1832	$self->{tls} or return; # tls session might have gone away in callback
		1833	}
		1834
		1835	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1836	return $self->_tls_error ($tmp)
		1837	if $tmp != $ERROR_WANT_READ
		1838	&& ($tmp != $ERROR_SYSCALL || $!);
		1839
		1840	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
809	$self->{wbuf} .= $buf;	1841	$self->{wbuf} .= $tmp;
810	$self->_drain_wbuf;	1842	$self->_drain_wbuf;
		1843	$self->{tls} or return; # tls session might have gone away in callback
811	}	1844	}
812		1845
813	while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {	1846	$self->{_on_starttls}
814	$self->{rbuf} .= $buf;	1847	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
815	$self->_drain_rbuf;	1848	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
816	}
817
818	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
819
820	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
821	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
822	$self->error;
823	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
824	$! = &Errno::EIO;
825	$self->error;
826	}
827
828	# all others are fine for our purposes
829	}
830	}	1849	}
831		1850
832	=item $handle->starttls ($tls[, $tls_ctx])	1851	=item $handle->starttls ($tls[, $tls_ctx])
833		1852
834	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1853	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
835	object is created, you can also do that at a later time by calling	1854	object is created, you can also do that at a later time by calling
836	C<starttls>.	1855	C<starttls>.
837		1856
		1857	Starting TLS is currently an asynchronous operation - when you push some
		1858	write data and then call C<< ->starttls >> then TLS negotiation will start
		1859	immediately, after which the queued write data is then sent.
		1860
838	The first argument is the same as the C<tls> constructor argument (either	1861	The first argument is the same as the C<tls> constructor argument (either
839	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1862	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
840		1863
841	The second argument is the optional C<Net::SSLeay::CTX> object that is	1864	The second argument is the optional C<AnyEvent::TLS> object that is used
842	used when AnyEvent::Handle has to create its own TLS connection object.	1865	when AnyEvent::Handle has to create its own TLS connection object, or
		1866	a hash reference with C<< key => value >> pairs that will be used to
		1867	construct a new context.
843		1868
844	=cut	1869	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1870	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1871	changed to your liking. Note that the handshake might have already started
		1872	when this function returns.
845		1873
846	# TODO: maybe document...	1874	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1875	handshakes on the same stream. Best do not attempt to use the stream after
		1876	stopping TLS.
		1877
		1878	This method may invoke callbacks (and therefore the handle might be
		1879	destroyed after it returns).
		1880
		1881	=cut
		1882
		1883	our %TLS_CACHE; #TODO not yet documented, should we?
		1884
847	sub starttls {	1885	sub starttls {
848	my ($self, $ssl, $ctx) = @_;	1886	my ($self, $tls, $ctx) = @_;
849		1887
850	$self->stoptls;	1888	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1889	if $self->{tls};
851		1890
852	if ($ssl eq "accept") {	1891	$self->{tls} = $tls;
853	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1892	$self->{tls_ctx} = $ctx if @_ > 2;
854	Net::SSLeay::set_accept_state ($ssl);	1893
855	} elsif ($ssl eq "connect") {	1894	return unless $self->{fh};
856	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1895
857	Net::SSLeay::set_connect_state ($ssl);	1896	require Net::SSLeay;
		1897
		1898	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1899	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1900
		1901	$tls = delete $self->{tls};
		1902	$ctx = $self->{tls_ctx};
		1903
		1904	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1905
		1906	if ("HASH" eq ref $ctx) {
		1907	require AnyEvent::TLS;
		1908
		1909	if ($ctx->{cache}) {
		1910	my $key = $ctx+0;
		1911	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1912	} else {
		1913	$ctx = new AnyEvent::TLS %$ctx;
		1914	}
		1915	}
858	}	1916
859		1917	$self->{tls_ctx} = $ctx || TLS_CTX ();
860	$self->{tls} = $ssl;	1918	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
861		1919
862	# basically, this is deep magic (because SSL_read should have the same issues)	1920	# basically, this is deep magic (because SSL_read should have the same issues)
863	# but the openssl maintainers basically said: "trust us, it just works".	1921	# but the openssl maintainers basically said: "trust us, it just works".
864	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1922	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
865	# and mismaintained ssleay-module doesn't even offer them).	1923	# and mismaintained ssleay-module doesn't even offer them).
866	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1924	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1925	#
		1926	# in short: this is a mess.
		1927	#
		1928	# note that we do not try to keep the length constant between writes as we are required to do.
		1929	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1930	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1931	# have identity issues in that area.
867	Net::SSLeay::CTX_set_mode ($self->{tls},	1932	# Net::SSLeay::CTX_set_mode ($ssl,
868	(eval { Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	1933	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
869	| (eval { Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	1934	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1935	Net::SSLeay::CTX_set_mode ($tls, 1|2);
870		1936
871	$self->{tls_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1937	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
872	$self->{tls_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1938	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
873		1939
		1940	Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf});
		1941
874	Net::SSLeay::set_bio ($ssl, $self->{tls_rbio}, $self->{tls_wbio});	1942	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
875		1943
876	$self->{filter_w} = sub {	1944	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
877	$_[0]{tls_wbuf} .= ${$_[1]};	1945	if $self->{on_starttls};
878	&_dotls;	1946
879	};	1947	&_dotls; # need to trigger the initial handshake
880	$self->{filter_r} = sub {	1948	$self->start_read; # make sure we actually do read
881	Net::SSLeay::BIO_write ($_[0]{tls_rbio}, ${$_[1]});
882	&_dotls;
883	};
884	}	1949	}
885		1950
886	=item $handle->stoptls	1951	=item $handle->stoptls
887		1952
888	Destroys the SSL connection, if any. Partial read or write data will be	1953	Shuts down the SSL connection - this makes a proper EOF handshake by
889	lost.	1954	sending a close notify to the other side, but since OpenSSL doesn't
		1955	support non-blocking shut downs, it is not guaranteed that you can re-use
		1956	the stream afterwards.
		1957
		1958	This method may invoke callbacks (and therefore the handle might be
		1959	destroyed after it returns).
890		1960
891	=cut	1961	=cut
892		1962
893	sub stoptls {	1963	sub stoptls {
894	my ($self) = @_;	1964	my ($self) = @_;
895		1965
896	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	1966	if ($self->{tls} && $self->{fh}) {
897	delete $self->{tls_rbio};	1967	Net::SSLeay::shutdown ($self->{tls});
898	delete $self->{tls_wbio};	1968
899	delete $self->{tls_wbuf};	1969	&_dotls;
900	delete $self->{filter_r};	1970
901	delete $self->{filter_w};	1971	# # we don't give a shit. no, we do, but we can't. no...#d#
		1972	# # we, we... have to use openssl :/#d#
		1973	# &_freetls;#d#
		1974	}
		1975	}
		1976
		1977	sub _freetls {
		1978	my ($self) = @_;
		1979
		1980	return unless $self->{tls};
		1981
		1982	$self->{tls_ctx}->_put_session (delete $self->{tls})
		1983	if $self->{tls} > 0;
		1984
		1985	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
902	}	1986	}
903		1987
904	sub DESTROY {	1988	sub DESTROY {
905	my $self = shift;	1989	my ($self) = @_;
906		1990
907	$self->stoptls;	1991	&_freetls;
		1992
		1993	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1994
		1995	if ($linger && length $self->{wbuf} && $self->{fh}) {
		1996	my $fh = delete $self->{fh};
		1997	my $wbuf = delete $self->{wbuf};
		1998
		1999	my @linger;
		2000
		2001	push @linger, AE::io $fh, 1, sub {
		2002	my $len = syswrite $fh, $wbuf, length $wbuf;
		2003
		2004	if ($len > 0) {
		2005	substr $wbuf, 0, $len, "";
		2006	} else {
		2007	@linger = (); # end
		2008	}
		2009	};
		2010	push @linger, AE::timer $linger, 0, sub {
		2011	@linger = ();
		2012	};
		2013	}
908	}	2014	}
		2015
		2016	=item $handle->destroy
		2017
		2018	Shuts down the handle object as much as possible - this call ensures that
		2019	no further callbacks will be invoked and as many resources as possible
		2020	will be freed. Any method you will call on the handle object after
		2021	destroying it in this way will be silently ignored (and it will return the
		2022	empty list).
		2023
		2024	Normally, you can just "forget" any references to an AnyEvent::Handle
		2025	object and it will simply shut down. This works in fatal error and EOF
		2026	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2027	callback, so when you want to destroy the AnyEvent::Handle object from
		2028	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2029	that case.
		2030
		2031	Destroying the handle object in this way has the advantage that callbacks
		2032	will be removed as well, so if those are the only reference holders (as
		2033	is common), then one doesn't need to do anything special to break any
		2034	reference cycles.
		2035
		2036	The handle might still linger in the background and write out remaining
		2037	data, as specified by the C<linger> option, however.
		2038
		2039	=cut
		2040
		2041	sub destroy {
		2042	my ($self) = @_;
		2043
		2044	$self->DESTROY;
		2045	%$self = ();
		2046	bless $self, "AnyEvent::Handle::destroyed";
		2047	}
		2048
		2049	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2050	#nop
		2051	}
		2052
		2053	=item $handle->destroyed
		2054
		2055	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2056	->destroy >>, true otherwise.
		2057
		2058	Can be useful to decide whether the handle is still valid after some
		2059	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2060	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2061	can destroy the handle, so work can be avoided by checking sometimes:
		2062
		2063	$hdl->starttls ("accept");
		2064	return if $hdl->destroyed;
		2065	$hdl->push_write (...
		2066
		2067	Note that the call to C<push_write> will silently be ignored if the handle
		2068	has been destroyed, so often you can just ignore the possibility of the
		2069	handle being destroyed.
		2070
		2071	=cut
		2072
		2073	sub destroyed { 0 }
		2074	sub AnyEvent::Handle::destroyed::destroyed { 1 }
909		2075
910	=item AnyEvent::Handle::TLS_CTX	2076	=item AnyEvent::Handle::TLS_CTX
911		2077
912	This function creates and returns the Net::SSLeay::CTX object used by	2078	This function creates and returns the AnyEvent::TLS object used by default
913	default for TLS mode.	2079	for TLS mode.
914		2080
915	The context is created like this:	2081	The context is created by calling L<AnyEvent::TLS> without any arguments.
916
917	Net::SSLeay::load_error_strings;
918	Net::SSLeay::SSLeay_add_ssl_algorithms;
919	Net::SSLeay::randomize;
920
921	my $CTX = Net::SSLeay::CTX_new;
922
923	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
924		2082
925	=cut	2083	=cut
926		2084
927	our $TLS_CTX;	2085	our $TLS_CTX;
928		2086
929	sub TLS_CTX() {	2087	sub TLS_CTX() {
930	$TLS_CTX || do {	2088	$TLS_CTX ||= do {
931	require Net::SSLeay;	2089	require AnyEvent::TLS;
932		2090
933	Net::SSLeay::load_error_strings ();	2091	new AnyEvent::TLS
934	Net::SSLeay::SSLeay_add_ssl_algorithms ();
935	Net::SSLeay::randomize ();
936
937	$TLS_CTX = Net::SSLeay::CTX_new ();
938
939	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
940
941	$TLS_CTX
942	}	2092	}
943	}	2093	}
944		2094
945	=back	2095	=back
946		2096
		2097
		2098	=head1 NONFREQUENTLY ASKED QUESTIONS
		2099
		2100	=over 4
		2101
		2102	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2103	still get further invocations!
		2104
		2105	That's because AnyEvent::Handle keeps a reference to itself when handling
		2106	read or write callbacks.
		2107
		2108	It is only safe to "forget" the reference inside EOF or error callbacks,
		2109	from within all other callbacks, you need to explicitly call the C<<
		2110	->destroy >> method.
		2111
		2112	=item I get different callback invocations in TLS mode/Why can't I pause
		2113	reading?
		2114
		2115	Unlike, say, TCP, TLS connections do not consist of two independent
		2116	communication channels, one for each direction. Or put differently. The
		2117	read and write directions are not independent of each other: you cannot
		2118	write data unless you are also prepared to read, and vice versa.
		2119
		2120	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		2121	callback invocations when you are not expecting any read data - the reason
		2122	is that AnyEvent::Handle always reads in TLS mode.
		2123
		2124	During the connection, you have to make sure that you always have a
		2125	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2126	connection (or when you no longer want to use it) you can call the
		2127	C<destroy> method.
		2128
		2129	=item How do I read data until the other side closes the connection?
		2130
		2131	If you just want to read your data into a perl scalar, the easiest way
		2132	to achieve this is by setting an C<on_read> callback that does nothing,
		2133	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2134	will be in C<$_[0]{rbuf}>:
		2135
		2136	$handle->on_read (sub { });
		2137	$handle->on_eof (undef);
		2138	$handle->on_error (sub {
		2139	my $data = delete $_[0]{rbuf};
		2140	});
		2141
		2142	The reason to use C<on_error> is that TCP connections, due to latencies
		2143	and packets loss, might get closed quite violently with an error, when in
		2144	fact, all data has been received.
		2145
		2146	It is usually better to use acknowledgements when transferring data,
		2147	to make sure the other side hasn't just died and you got the data
		2148	intact. This is also one reason why so many internet protocols have an
		2149	explicit QUIT command.
		2150
		2151	=item I don't want to destroy the handle too early - how do I wait until
		2152	all data has been written?
		2153
		2154	After writing your last bits of data, set the C<on_drain> callback
		2155	and destroy the handle in there - with the default setting of
		2156	C<low_water_mark> this will be called precisely when all data has been
		2157	written to the socket:
		2158
		2159	$handle->push_write (...);
		2160	$handle->on_drain (sub {
		2161	warn "all data submitted to the kernel\n";
		2162	undef $handle;
		2163	});
		2164
		2165	If you just want to queue some data and then signal EOF to the other side,
		2166	consider using C<< ->push_shutdown >> instead.
		2167
		2168	=item I want to contact a TLS/SSL server, I don't care about security.
		2169
		2170	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2171	simply connect to it and then create the AnyEvent::Handle with the C<tls>
		2172	parameter:
		2173
		2174	tcp_connect $host, $port, sub {
		2175	my ($fh) = @_;
		2176
		2177	my $handle = new AnyEvent::Handle
		2178	fh => $fh,
		2179	tls => "connect",
		2180	on_error => sub { ... };
		2181
		2182	$handle->push_write (...);
		2183	};
		2184
		2185	=item I want to contact a TLS/SSL server, I do care about security.
		2186
		2187	Then you should additionally enable certificate verification, including
		2188	peername verification, if the protocol you use supports it (see
		2189	L<AnyEvent::TLS>, C<verify_peername>).
		2190
		2191	E.g. for HTTPS:
		2192
		2193	tcp_connect $host, $port, sub {
		2194	my ($fh) = @_;
		2195
		2196	my $handle = new AnyEvent::Handle
		2197	fh => $fh,
		2198	peername => $host,
		2199	tls => "connect",
		2200	tls_ctx => { verify => 1, verify_peername => "https" },
		2201	...
		2202
		2203	Note that you must specify the hostname you connected to (or whatever
		2204	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2205	peername verification will be done.
		2206
		2207	The above will use the system-dependent default set of trusted CA
		2208	certificates. If you want to check against a specific CA, add the
		2209	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2210
		2211	tls_ctx => {
		2212	verify => 1,
		2213	verify_peername => "https",
		2214	ca_file => "my-ca-cert.pem",
		2215	},
		2216
		2217	=item I want to create a TLS/SSL server, how do I do that?
		2218
		2219	Well, you first need to get a server certificate and key. You have
		2220	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2221	self-signed certificate (cheap. check the search engine of your choice,
		2222	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2223	nice program for that purpose).
		2224
		2225	Then create a file with your private key (in PEM format, see
		2226	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2227	file should then look like this:
		2228
		2229	-----BEGIN RSA PRIVATE KEY-----
		2230	...header data
		2231	... lots of base64'y-stuff
		2232	-----END RSA PRIVATE KEY-----
		2233
		2234	-----BEGIN CERTIFICATE-----
		2235	... lots of base64'y-stuff
		2236	-----END CERTIFICATE-----
		2237
		2238	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2239	specify this file as C<cert_file>:
		2240
		2241	tcp_server undef, $port, sub {
		2242	my ($fh) = @_;
		2243
		2244	my $handle = new AnyEvent::Handle
		2245	fh => $fh,
		2246	tls => "accept",
		2247	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2248	...
		2249
		2250	When you have intermediate CA certificates that your clients might not
		2251	know about, just append them to the C<cert_file>.
		2252
		2253	=back
		2254
		2255
		2256	=head1 SUBCLASSING AnyEvent::Handle
		2257
		2258	In many cases, you might want to subclass AnyEvent::Handle.
		2259
		2260	To make this easier, a given version of AnyEvent::Handle uses these
		2261	conventions:
		2262
		2263	=over 4
		2264
		2265	=item * all constructor arguments become object members.
		2266
		2267	At least initially, when you pass a C<tls>-argument to the constructor it
		2268	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2269	mutated later on (for example C<tls> will hold the TLS connection object).
		2270
		2271	=item * other object member names are prefixed with an C<_>.
		2272
		2273	All object members not explicitly documented (internal use) are prefixed
		2274	with an underscore character, so the remaining non-C<_>-namespace is free
		2275	for use for subclasses.
		2276
		2277	=item * all members not documented here and not prefixed with an underscore
		2278	are free to use in subclasses.
		2279
		2280	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2281	member variables, but thats just life, at least it is documented.
		2282
		2283	=back
		2284
947	=head1 AUTHOR	2285	=head1 AUTHOR
948		2286
949	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	2287	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
950		2288
951	=cut	2289	=cut

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