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Revision 1.6 by elmex, Mon Apr 28 09:27:47 2008 UTC vs.
Revision 1.255 by root, Wed Jul 29 13:02:48 2020 UTC

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict;
5
6	use AnyEvent;
7	use IO::Handle;
8	use Errno qw/EAGAIN EINTR/;
9
10	=head1 NAME	1	=head1 NAME
11		2
12	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	3	AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
13
14	=head1 VERSION
15
16	Version 0.01
17
18	=cut
19
20	our $VERSION = '0.01';
21		4
22	=head1 SYNOPSIS	5	=head1 SYNOPSIS
23		6
24	use AnyEvent;	7	use AnyEvent;
25	use AnyEvent::Handle;	8	use AnyEvent::Handle;
26		9
27	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
28		11
29	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	12	my $hdl; $hdl = new AnyEvent::Handle
		13	fh => \*STDIN,
		14	on_error => sub {
		15	my ($hdl, $fatal, $msg) = @_;
		16	AE::log error => $msg;
		17	$hdl->destroy;
		18	$cv->send;
		19	};
30		20
31	$ae_fh->on_eof (sub { $cv->broadcast });	21	# send some request line
		22	$hdl->push_write ("getinfo\015\012");
32		23
33	$ae_fh->readlines (sub {	24	# read the response line
		25	$hdl->push_read (line => sub {
34	my ($ae_fh, @lines) = @_;	26	my ($hdl, $line) = @_;
35	for (@lines) {	27	say "got line <$line>";
		28	$cv->send;
		29	});
		30
		31	$cv->recv;
		32
		33	=head1 DESCRIPTION
		34
		35	This is a helper module to make it easier to do event-based I/O
		36	on stream-based filehandles (sockets, pipes, and other stream
		37	things). Specifically, it doesn't work as expected on files, packet-based
		38	sockets or similar things.
		39
		40	The L<AnyEvent::Intro> tutorial contains some well-documented
		41	AnyEvent::Handle examples.
		42
		43	In the following, where the documentation refers to "bytes", it means
		44	characters. As sysread and syswrite are used for all I/O, their
		45	treatment of characters applies to this module as well.
		46
		47	At the very minimum, you should specify C<fh> or C<connect>, and the
		48	C<on_error> callback.
		49
		50	All callbacks will be invoked with the handle object as their first
		51	argument.
		52
		53	=cut
		54
		55	package AnyEvent::Handle;
		56
		57	use Scalar::Util ();
		58	use List::Util ();
		59	use Carp ();
		60	use Errno qw(EAGAIN EWOULDBLOCK EINTR);
		61
		62	use AnyEvent (); BEGIN { AnyEvent::common_sense }
		63	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		64
		65	our $VERSION = $AnyEvent::VERSION;
		66
		67	sub _load_func($) {
		68	my $func = $_[0];
		69
		70	unless (defined &$func) {
		71	my $pkg = $func;
		72	do {
		73	$pkg =~ s/::[^:]+$//
		74	or return;
		75	eval "require $pkg";
		76	} until defined &$func;
		77	}
		78
		79	\&$func
		80	}
		81
		82	sub MAX_READ_SIZE() { 131072 }
		83
		84	=head1 METHODS
		85
		86	=over 4
		87
		88	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
		89
		90	The constructor supports these arguments (all as C<< key => value >> pairs).
		91
		92	=over 4
		93
		94	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
		95
		96	The filehandle this L<AnyEvent::Handle> object will operate on.
		97	NOTE: The filehandle will be set to non-blocking mode (using
		98	C<AnyEvent::fh_unblock>) by the constructor and needs to stay in
		99	that mode.
		100
		101	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
		102
		103	Try to connect to the specified host and service (port), using
		104	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		105	default C<peername>.
		106
		107	You have to specify either this parameter, or C<fh>, above.
		108
		109	It is possible to push requests on the read and write queues, and modify
		110	properties of the stream, even while AnyEvent::Handle is connecting.
		111
		112	When this parameter is specified, then the C<on_prepare>,
		113	C<on_connect_error> and C<on_connect> callbacks will be called under the
		114	appropriate circumstances:
		115
		116	=over 4
		117
		118	=item on_prepare => $cb->($handle)
		119
		120	This (rarely used) callback is called before a new connection is
		121	attempted, but after the file handle has been created (you can access that
		122	file handle via C<< $handle->{fh} >>). It could be used to prepare the
		123	file handle with parameters required for the actual connect (as opposed to
		124	settings that can be changed when the connection is already established).
		125
		126	The return value of this callback should be the connect timeout value in
		127	seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
		128	default timeout is to be used).
		129
		130	=item on_connect => $cb->($handle, $host, $port, $retry->())
		131
		132	This callback is called when a connection has been successfully established.
		133
		134	The peer's numeric host and port (the socket peername) are passed as
		135	parameters, together with a retry callback. At the time it is called the
		136	read and write queues, EOF status, TLS status and similar properties of
		137	the handle will have been reset.
		138
		139	If, for some reason, the handle is not acceptable, calling C<$retry> will
		140	continue with the next connection target (in case of multi-homed hosts or
		141	SRV records there can be multiple connection endpoints). The C<$retry>
		142	callback can be invoked after the connect callback returns, i.e. one can
		143	start a handshake and then decide to retry with the next host if the
		144	handshake fails.
		145
		146	In most cases, you should ignore the C<$retry> parameter.
		147
		148	=item on_connect_error => $cb->($handle, $message)
		149
		150	This callback is called when the connection could not be
		151	established. C<$!> will contain the relevant error code, and C<$message> a
		152	message describing it (usually the same as C<"$!">).
		153
		154	If this callback isn't specified, then C<on_error> will be called with a
		155	fatal error instead.
		156
		157	=back
		158
		159	=item on_error => $cb->($handle, $fatal, $message)
		160
		161	This is the error callback, which is called when, well, some error
		162	occured, such as not being able to resolve the hostname, failure to
		163	connect, or a read error.
		164
		165	Some errors are fatal (which is indicated by C<$fatal> being true). On
		166	fatal errors the handle object will be destroyed (by a call to C<< ->
		167	destroy >>) after invoking the error callback (which means you are free to
		168	examine the handle object). Examples of fatal errors are an EOF condition
		169	with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
		170	cases where the other side can close the connection at will, it is
		171	often easiest to not report C<EPIPE> errors in this callback.
		172
		173	AnyEvent::Handle tries to find an appropriate error code for you to check
		174	against, but in some cases (TLS errors), this does not work well.
		175
		176	If you report the error to the user, it is recommended to always output
		177	the C<$message> argument in human-readable error messages (you don't need
		178	to report C<"$!"> if you report C<$message>).
		179
		180	If you want to react programmatically to the error, then looking at C<$!>
		181	and comparing it against some of the documented C<Errno> values is usually
		182	better than looking at the C<$message>.
		183
		184	Non-fatal errors can be retried by returning, but it is recommended
		185	to simply ignore this parameter and instead abondon the handle object
		186	when this callback is invoked. Examples of non-fatal errors are timeouts
		187	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		188
		189	On entry to the callback, the value of C<$!> contains the operating
		190	system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		191	C<EPROTO>).
		192
		193	While not mandatory, it is I<highly> recommended to set this callback, as
		194	you will not be notified of errors otherwise. The default just calls
		195	C<croak>.
		196
		197	=item on_read => $cb->($handle)
		198
		199	This sets the default read callback, which is called when data arrives
		200	and no read request is in the queue (unlike read queue callbacks, this
		201	callback will only be called when at least one octet of data is in the
		202	read buffer).
		203
		204	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
		205	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		206	must not enlarge or modify the read buffer, you can only remove data at
		207	the beginning from it.
		208
		209	You can also call C<< ->push_read (...) >> or any other function that
		210	modifies the read queue. Or do both. Or ...
		211
		212	When an EOF condition is detected, AnyEvent::Handle will first try to
		213	feed all the remaining data to the queued callbacks and C<on_read> before
		214	calling the C<on_eof> callback. If no progress can be made, then a fatal
		215	error will be raised (with C<$!> set to C<EPIPE>).
		216
		217	Note that, unlike requests in the read queue, an C<on_read> callback
		218	doesn't mean you I<require> some data: if there is an EOF and there
		219	are outstanding read requests then an error will be flagged. With an
		220	C<on_read> callback, the C<on_eof> callback will be invoked.
		221
		222	=item on_eof => $cb->($handle)
		223
		224	Set the callback to be called when an end-of-file condition is detected,
		225	i.e. in the case of a socket, when the other side has closed the
		226	connection cleanly, and there are no outstanding read requests in the
		227	queue (if there are read requests, then an EOF counts as an unexpected
		228	connection close and will be flagged as an error).
		229
		230	For sockets, this just means that the other side has stopped sending data,
		231	you can still try to write data, and, in fact, one can return from the EOF
		232	callback and continue writing data, as only the read part has been shut
		233	down.
		234
		235	If an EOF condition has been detected but no C<on_eof> callback has been
		236	set, then a fatal error will be raised with C<$!> set to <0>.
		237
		238	=item on_drain => $cb->($handle)
		239
		240	This sets the callback that is called once when the write buffer becomes
		241	empty (and immediately when the handle object is created).
		242
		243	To append to the write buffer, use the C<< ->push_write >> method.
		244
		245	This callback is useful when you don't want to put all of your write data
		246	into the queue at once, for example, when you want to write the contents
		247	of some file to the socket you might not want to read the whole file into
		248	memory and push it into the queue, but instead only read more data from
		249	the file when the write queue becomes empty.
		250
		251	=item timeout => $fractional_seconds
		252
		253	=item rtimeout => $fractional_seconds
		254
		255	=item wtimeout => $fractional_seconds
		256
		257	If non-zero, then these enables an "inactivity" timeout: whenever this
		258	many seconds pass without a successful read or write on the underlying
		259	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
		260	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		261	error will be raised).
		262
		263	There are three variants of the timeouts that work independently of each
		264	other, for both read and write (triggered when nothing was read I<OR>
		265	written), just read (triggered when nothing was read), and just write:
		266	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		267	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		268	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		269
		270	Note that timeout processing is active even when you do not have any
		271	outstanding read or write requests: If you plan to keep the connection
		272	idle then you should disable the timeout temporarily or ignore the
		273	timeout in the corresponding C<on_timeout> callback, in which case
		274	AnyEvent::Handle will simply restart the timeout.
		275
		276	Zero (the default) disables the corresponding timeout.
		277
		278	=item on_timeout => $cb->($handle)
		279
		280	=item on_rtimeout => $cb->($handle)
		281
		282	=item on_wtimeout => $cb->($handle)
		283
		284	Called whenever the inactivity timeout passes. If you return from this
		285	callback, then the timeout will be reset as if some activity had happened,
		286	so this condition is not fatal in any way.
		287
		288	=item rbuf_max => <bytes>
		289
		290	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		291	when the read buffer ever (strictly) exceeds this size. This is useful to
		292	avoid some forms of denial-of-service attacks.
		293
		294	For example, a server accepting connections from untrusted sources should
		295	be configured to accept only so-and-so much data that it cannot act on
		296	(for example, when expecting a line, an attacker could send an unlimited
		297	amount of data without a callback ever being called as long as the line
		298	isn't finished).
		299
		300	=item wbuf_max => <bytes>
		301
		302	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		303	when the write buffer ever (strictly) exceeds this size. This is useful to
		304	avoid some forms of denial-of-service attacks.
		305
		306	Although the units of this parameter is bytes, this is the I<raw> number
		307	of bytes not yet accepted by the kernel. This can make a difference when
		308	you e.g. use TLS, as TLS typically makes your write data larger (but it
		309	can also make it smaller due to compression).
		310
		311	As an example of when this limit is useful, take a chat server that sends
		312	chat messages to a client. If the client does not read those in a timely
		313	manner then the send buffer in the server would grow unbounded.
		314
		315	=item autocork => <boolean>
		316
		317	When disabled (the default), C<push_write> will try to immediately
		318	write the data to the handle if possible. This avoids having to register
		319	a write watcher and wait for the next event loop iteration, but can
		320	be inefficient if you write multiple small chunks (on the wire, this
		321	disadvantage is usually avoided by your kernel's nagle algorithm, see
		322	C<no_delay>, but this option can save costly syscalls).
		323
		324	When enabled, writes will always be queued till the next event loop
		325	iteration. This is efficient when you do many small writes per iteration,
		326	but less efficient when you do a single write only per iteration (or when
		327	the write buffer often is full). It also increases write latency.
		328
		329	=item no_delay => <boolean>
		330
		331	When doing small writes on sockets, your operating system kernel might
		332	wait a bit for more data before actually sending it out. This is called
		333	the Nagle algorithm, and usually it is beneficial.
		334
		335	In some situations you want as low a delay as possible, which can be
		336	accomplishd by setting this option to a true value.
		337
		338	The default is your operating system's default behaviour (most likely
		339	enabled). This option explicitly enables or disables it, if possible.
		340
		341	=item keepalive => <boolean>
		342
		343	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		344	normally, TCP connections have no time-out once established, so TCP
		345	connections, once established, can stay alive forever even when the other
		346	side has long gone. TCP keepalives are a cheap way to take down long-lived
		347	TCP connections when the other side becomes unreachable. While the default
		348	is OS-dependent, TCP keepalives usually kick in after around two hours,
		349	and, if the other side doesn't reply, take down the TCP connection some 10
		350	to 15 minutes later.
		351
		352	It is harmless to specify this option for file handles that do not support
		353	keepalives, and enabling it on connections that are potentially long-lived
		354	is usually a good idea.
		355
		356	=item oobinline => <boolean>
		357
		358	BSD majorly fucked up the implementation of TCP urgent data. The result
		359	is that almost no OS implements TCP according to the specs, and every OS
		360	implements it slightly differently.
		361
		362	If you want to handle TCP urgent data, then setting this flag (the default
		363	is enabled) gives you the most portable way of getting urgent data, by
		364	putting it into the stream.
		365
		366	Since BSD emulation of OOB data on top of TCP's urgent data can have
		367	security implications, AnyEvent::Handle sets this flag automatically
		368	unless explicitly specified. Note that setting this flag after
		369	establishing a connection I<may> be a bit too late (data loss could
		370	already have occured on BSD systems), but at least it will protect you
		371	from most attacks.
		372
		373	=item read_size => <bytes>
		374
		375	The initial read block size, the number of bytes this module will try
		376	to read during each loop iteration. Each handle object will consume
		377	at least this amount of memory for the read buffer as well, so when
		378	handling many connections watch out for memory requirements). See also
		379	C<max_read_size>. Default: C<2048>.
		380
		381	=item max_read_size => <bytes>
		382
		383	The maximum read buffer size used by the dynamic adjustment
		384	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		385	one go it will double C<read_size> up to the maximum given by this
		386	option. Default: C<131072> or C<read_size>, whichever is higher.
		387
		388	=item low_water_mark => <bytes>
		389
		390	Sets the number of bytes (default: C<0>) that make up an "empty" write
		391	buffer: If the buffer reaches this size or gets even samller it is
		392	considered empty.
		393
		394	Sometimes it can be beneficial (for performance reasons) to add data to
		395	the write buffer before it is fully drained, but this is a rare case, as
		396	the operating system kernel usually buffers data as well, so the default
		397	is good in almost all cases.
		398
		399	=item linger => <seconds>
		400
		401	If this is non-zero (default: C<3600>), the destructor of the
		402	AnyEvent::Handle object will check whether there is still outstanding
		403	write data and will install a watcher that will write this data to the
		404	socket. No errors will be reported (this mostly matches how the operating
		405	system treats outstanding data at socket close time).
		406
		407	This will not work for partial TLS data that could not be encoded
		408	yet. This data will be lost. Calling the C<stoptls> method in time might
		409	help.
		410
		411	=item peername => $string
		412
		413	A string used to identify the remote site - usually the DNS hostname
		414	(I<not> IDN!) used to create the connection, rarely the IP address.
		415
		416	Apart from being useful in error messages, this string is also used in TLS
		417	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		418	verification will be skipped when C<peername> is not specified or is
		419	C<undef>.
		420
		421	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		422
		423	When this parameter is given, it enables TLS (SSL) mode, that means
		424	AnyEvent will start a TLS handshake as soon as the connection has been
		425	established and will transparently encrypt/decrypt data afterwards.
		426
		427	All TLS protocol errors will be signalled as C<EPROTO>, with an
		428	appropriate error message.
		429
		430	TLS mode requires Net::SSLeay to be installed (it will be loaded
		431	automatically when you try to create a TLS handle): this module doesn't
		432	have a dependency on that module, so if your module requires it, you have
		433	to add the dependency yourself. If Net::SSLeay cannot be loaded or is too
		434	old, you get an C<EPROTO> error.
		435
		436	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		437	C<accept>, and for the TLS client side of a connection, use C<connect>
		438	mode.
		439
		440	You can also provide your own TLS connection object, but you have
		441	to make sure that you call either C<Net::SSLeay::set_connect_state>
		442	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		443	AnyEvent::Handle. Also, this module will take ownership of this connection
		444	object.
		445
		446	At some future point, AnyEvent::Handle might switch to another TLS
		447	implementation, then the option to use your own session object will go
		448	away.
		449
		450	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		451	passing in the wrong integer will lead to certain crash. This most often
		452	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		453	segmentation fault.
		454
		455	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
		456
		457	=item tls_ctx => $anyevent_tls
		458
		459	Use the given C<AnyEvent::TLS> object to create the new TLS connection
		460	(unless a connection object was specified directly). If this
		461	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		462	C<AnyEvent::Handle::TLS_CTX>.
		463
		464	Instead of an object, you can also specify a hash reference with C<< key
		465	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		466	new TLS context object.
		467
		468	=item on_starttls => $cb->($handle, $success[, $error_message])
		469
		470	This callback will be invoked when the TLS/SSL handshake has finished. If
		471	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		472	(C<on_stoptls> will not be called in this case).
		473
		474	The session in C<< $handle->{tls} >> can still be examined in this
		475	callback, even when the handshake was not successful.
		476
		477	TLS handshake failures will not cause C<on_error> to be invoked when this
		478	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		479
		480	Without this callback, handshake failures lead to C<on_error> being
		481	called as usual.
		482
		483	Note that you cannot just call C<starttls> again in this callback. If you
		484	need to do that, start an zero-second timer instead whose callback can
		485	then call C<< ->starttls >> again.
		486
		487	=item on_stoptls => $cb->($handle)
		488
		489	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		490	set, then it will be invoked after freeing the TLS session. If it is not,
		491	then a TLS shutdown condition will be treated like a normal EOF condition
		492	on the handle.
		493
		494	The session in C<< $handle->{tls} >> can still be examined in this
		495	callback.
		496
		497	This callback will only be called on TLS shutdowns, not when the
		498	underlying handle signals EOF.
		499
		500	=item json => L<JSON>, L<JSON::PP> or L<JSON::XS> object
		501
		502	This is the json coder object used by the C<json> read and write types.
		503
		504	If you don't supply it, then AnyEvent::Handle will create and use a
		505	suitable one (on demand), which will write and expect UTF-8 encoded
		506	JSON texts (either using L<JSON::XS> or L<JSON>). The written texts are
		507	guaranteed not to contain any newline character.
		508
		509	For security reasons, this encoder will likely I<not> handle numbers and
		510	strings, only arrays and objects/hashes. The reason is that originally
		511	JSON was self-delimited, but Dougles Crockford thought it was a splendid
		512	idea to redefine JSON incompatibly, so this is no longer true.
		513
		514	For protocols that used back-to-back JSON texts, this might lead to
		515	run-ins, where two or more JSON texts will be interpreted as one JSON
		516	text.
		517
		518	For this reason, if the default encoder uses L<JSON::XS>, it will default
		519	to not allowing anything but arrays and objects/hashes, at least for the
		520	forseeable future (it will change at some point). This might or might not
		521	be true for the L<JSON> module, so this might cause a security issue.
		522
		523	If you depend on either behaviour, you should create your own json object
		524	and pass it in explicitly.
		525
		526	=item cbor => L<CBOR::XS> object
		527
		528	This is the cbor coder object used by the C<cbor> read and write types.
		529
		530	If you don't supply it, then AnyEvent::Handle will create and use a
		531	suitable one (on demand), which will write CBOR without using extensions,
		532	if possible.
		533
		534	Note that you are responsible to depend on the L<CBOR::XS> module if you
		535	want to use this functionality, as AnyEvent does not have a dependency on
		536	it itself.
		537
		538	=back
		539
		540	=cut
		541
		542	sub new {
		543	my $class = shift;
		544	my $self = bless { @_ }, $class;
		545
		546	if ($self->{fh}) {
		547	$self->_start;
		548	return unless $self->{fh}; # could be gone by now
		549
		550	} elsif ($self->{connect}) {
		551	require AnyEvent::Socket;
		552
		553	$self->{peername} = $self->{connect}[0]
		554	unless exists $self->{peername};
		555
		556	$self->{_skip_drain_rbuf} = 1;
		557
		558	{
		559	Scalar::Util::weaken (my $self = $self);
		560
		561	$self->{_connect} =
		562	AnyEvent::Socket::tcp_connect (
		563	$self->{connect}[0],
		564	$self->{connect}[1],
		565	sub {
		566	my ($fh, $host, $port, $retry) = @_;
		567
		568	delete $self->{_connect}; # no longer needed
		569
		570	if ($fh) {
		571	$self->{fh} = $fh;
		572
		573	delete $self->{_skip_drain_rbuf};
		574	$self->_start;
		575
		576	$self->{on_connect}
		577	and $self->{on_connect}($self, $host, $port, sub {
		578	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		579	$self->{_skip_drain_rbuf} = 1;
		580	&$retry;
		581	});
		582
		583	} else {
		584	if ($self->{on_connect_error}) {
		585	$self->{on_connect_error}($self, "$!");
		586	$self->destroy if $self;
		587	} else {
		588	$self->error ($!, 1);
		589	}
		590	}
		591	},
		592	sub {
		593	local $self->{fh} = $_[0];
		594
		595	$self->{on_prepare}
		596	? $self->{on_prepare}->($self)
		597	: ()
		598	}
		599	);
		600	}
		601
		602	} else {
		603	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		604	}
		605
		606	$self
		607	}
		608
		609	sub _start {
		610	my ($self) = @_;
		611
		612	# too many clueless people try to use udp and similar sockets
		613	# with AnyEvent::Handle, do them a favour.
		614	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		615	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		616	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
		617
		618	AnyEvent::fh_unblock $self->{fh};
		619
		620	$self->{_activity} =
		621	$self->{_ractivity} =
		622	$self->{_wactivity} = AE::now;
		623
		624	$self->{read_size} ||= 2048;
		625	$self->{max_read_size} = $self->{read_size}
		626	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		627
		628	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		629	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		630	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		631
		632	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		633	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		634
		635	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		636
		637	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		638	if $self->{tls};
		639
		640	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
		641
		642	$self->start_read
		643	if $self->{on_read} || @{ $self->{_queue} };
		644
		645	$self->_drain_wbuf;
		646	}
		647
		648	=item $handle->error ($errno[, $fatal[, $message]])
		649
		650	Generates an error event, just like AnyEvent::Handle itself would do, i.e.
		651	calls the C<on_error> callback.
		652
		653	Te only rerquired parameter is C<$errno>, which sets C<$!>. C<$fatal>
		654	defaults to false and C<$message> defaults to the stringified version
		655	of C<$1>.
		656
		657	Example: generate C<EIO> when you read unexpected data.
		658
		659	$handle->push_read (line => sub {
		660	$_[1] eq "hello"
		661	or return $handle->error (Errno::EIO);
		662	});
		663
		664	=cut
		665
		666	sub error {
		667	my ($self, $errno, $fatal, $message) = @_;
		668
		669	$! = $errno;
		670	$message ||= "$!";
		671
		672	if ($self->{on_error}) {
		673	$self->{on_error}($self, $fatal, $message);
		674	$self->destroy if $fatal;
		675	} elsif ($self->{fh} || $self->{connect}) {
		676	$self->destroy;
		677	Carp::croak "AnyEvent::Handle uncaught error: $message";
		678	}
		679	}
		680
		681	=item $fh = $handle->fh
		682
		683	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		684
		685	=cut
		686
		687	sub fh { $_[0]{fh} }
		688
		689	=item $handle->on_error ($cb)
		690
		691	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		692
		693	=cut
		694
		695	sub on_error {
		696	$_[0]{on_error} = $_[1];
		697	}
		698
		699	=item $handle->on_eof ($cb)
		700
		701	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		702
		703	=cut
		704
		705	sub on_eof {
		706	$_[0]{on_eof} = $_[1];
		707	}
		708
		709	=item $handle->on_timeout ($cb)
		710
		711	=item $handle->on_rtimeout ($cb)
		712
		713	=item $handle->on_wtimeout ($cb)
		714
		715	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		716	callback, or disables the callback (but not the timeout) if C<$cb> =
		717	C<undef>. See the C<timeout> constructor argument and method.
		718
		719	=cut
		720
		721	# see below
		722
		723	=item $handle->autocork ($boolean)
		724
		725	Enables or disables the current autocork behaviour (see C<autocork>
		726	constructor argument). Changes will only take effect on the next write.
		727
		728	=cut
		729
		730	sub autocork {
		731	$_[0]{autocork} = $_[1];
		732	}
		733
		734	=item $handle->no_delay ($boolean)
		735
		736	Enables or disables the C<no_delay> setting (see constructor argument of
		737	the same name for details).
		738
		739	=cut
		740
		741	sub no_delay {
		742	$_[0]{no_delay} = $_[1];
		743
		744	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		745	if $_[0]{fh};
		746	}
		747
		748	=item $handle->keepalive ($boolean)
		749
		750	Enables or disables the C<keepalive> setting (see constructor argument of
		751	the same name for details).
		752
		753	=cut
		754
		755	sub keepalive {
		756	$_[0]{keepalive} = $_[1];
		757
		758	eval {
		759	local $SIG{__DIE__};
		760	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		761	if $_[0]{fh};
		762	};
		763	}
		764
		765	=item $handle->oobinline ($boolean)
		766
		767	Enables or disables the C<oobinline> setting (see constructor argument of
		768	the same name for details).
		769
		770	=cut
		771
		772	sub oobinline {
		773	$_[0]{oobinline} = $_[1];
		774
		775	eval {
		776	local $SIG{__DIE__};
		777	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		778	if $_[0]{fh};
		779	};
		780	}
		781
		782	=item $handle->on_starttls ($cb)
		783
		784	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		785
		786	=cut
		787
		788	sub on_starttls {
		789	$_[0]{on_starttls} = $_[1];
		790	}
		791
		792	=item $handle->on_stoptls ($cb)
		793
		794	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		795
		796	=cut
		797
		798	sub on_stoptls {
		799	$_[0]{on_stoptls} = $_[1];
		800	}
		801
		802	=item $handle->rbuf_max ($max_octets)
		803
		804	Configures the C<rbuf_max> setting (C<undef> disables it).
		805
		806	=item $handle->wbuf_max ($max_octets)
		807
		808	Configures the C<wbuf_max> setting (C<undef> disables it).
		809
		810	=cut
		811
		812	sub rbuf_max {
		813	$_[0]{rbuf_max} = $_[1];
		814	}
		815
		816	sub wbuf_max {
		817	$_[0]{wbuf_max} = $_[1];
		818	}
		819
		820	#############################################################################
		821
		822	=item $handle->timeout ($seconds)
		823
		824	=item $handle->rtimeout ($seconds)
		825
		826	=item $handle->wtimeout ($seconds)
		827
		828	Configures (or disables) the inactivity timeout.
		829
		830	The timeout will be checked instantly, so this method might destroy the
		831	handle before it returns.
		832
		833	=item $handle->timeout_reset
		834
		835	=item $handle->rtimeout_reset
		836
		837	=item $handle->wtimeout_reset
		838
		839	Reset the activity timeout, as if data was received or sent.
		840
		841	These methods are cheap to call.
		842
		843	=cut
		844
		845	for my $dir ("", "r", "w") {
		846	my $timeout = "${dir}timeout";
		847	my $tw = "_${dir}tw";
		848	my $on_timeout = "on_${dir}timeout";
		849	my $activity = "_${dir}activity";
		850	my $cb;
		851
		852	*$on_timeout = sub {
		853	$_[0]{$on_timeout} = $_[1];
		854	};
		855
		856	*$timeout = sub {
		857	my ($self, $new_value) = @_;
		858
		859	$new_value >= 0
		860	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		861
		862	$self->{$timeout} = $new_value;
		863	delete $self->{$tw}; &$cb;
		864	};
		865
		866	*{"${dir}timeout_reset"} = sub {
		867	$_[0]{$activity} = AE::now;
		868	};
		869
		870	# main workhorse:
		871	# reset the timeout watcher, as neccessary
		872	# also check for time-outs
		873	$cb = sub {
		874	my ($self) = @_;
		875
		876	if ($self->{$timeout} && $self->{fh}) {
		877	my $NOW = AE::now;
		878
		879	# when would the timeout trigger?
		880	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		881
		882	# now or in the past already?
		883	if ($after <= 0) {
		884	$self->{$activity} = $NOW;
		885
		886	if ($self->{$on_timeout}) {
		887	$self->{$on_timeout}($self);
		888	} else {
		889	$self->error (Errno::ETIMEDOUT);
		890	}
		891
		892	# callback could have changed timeout value, optimise
		893	return unless $self->{$timeout};
		894
		895	# calculate new after
		896	$after = $self->{$timeout};
		897	}
		898
		899	Scalar::Util::weaken $self;
		900	return unless $self; # ->error could have destroyed $self
		901
		902	$self->{$tw} ||= AE::timer $after, 0, sub {
		903	delete $self->{$tw};
		904	$cb->($self);
36	chomp;	905	};
37	print "Line: $_";	906	} else {
		907	delete $self->{$tw};
		908	}
		909	}
		910	}
		911
		912	#############################################################################
		913
		914	=back
		915
		916	=head2 WRITE QUEUE
		917
		918	AnyEvent::Handle manages two queues per handle, one for writing and one
		919	for reading.
		920
		921	The write queue is very simple: you can add data to its end, and
		922	AnyEvent::Handle will automatically try to get rid of it for you.
		923
		924	When data could be written and the write buffer is shorter then the low
		925	water mark, the C<on_drain> callback will be invoked once.
		926
		927	=over 4
		928
		929	=item $handle->on_drain ($cb)
		930
		931	Sets the C<on_drain> callback or clears it (see the description of
		932	C<on_drain> in the constructor).
		933
		934	This method may invoke callbacks (and therefore the handle might be
		935	destroyed after it returns).
		936
		937	=cut
		938
		939	sub on_drain {
		940	my ($self, $cb) = @_;
		941
		942	$self->{on_drain} = $cb;
		943
		944	$cb->($self)
		945	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		946	}
		947
		948	=item $handle->push_write ($data)
		949
		950	Queues the given scalar to be written. You can push as much data as
		951	you want (only limited by the available memory and C<wbuf_max>), as
		952	C<AnyEvent::Handle> buffers it independently of the kernel.
		953
		954	This method may invoke callbacks (and therefore the handle might be
		955	destroyed after it returns).
		956
		957	=cut
		958
		959	sub _drain_wbuf {
		960	my ($self) = @_;
		961
		962	if (!$self->{_ww} && length $self->{wbuf}) {
		963
		964	Scalar::Util::weaken $self;
		965
		966	my $cb = sub {
		967	my $len = syswrite $self->{fh}, $self->{wbuf};
		968
		969	if (defined $len) {
		970	substr $self->{wbuf}, 0, $len, "";
		971
		972	$self->{_activity} = $self->{_wactivity} = AE::now;
		973
		974	$self->{on_drain}($self)
		975	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		976	&& $self->{on_drain};
		977
		978	delete $self->{_ww} unless length $self->{wbuf};
		979	} elsif ($! != EAGAIN && $! != EINTR && $! != EWOULDBLOCK && $! != WSAEWOULDBLOCK) {
		980	$self->error ($!, 1);
		981	}
		982	};
		983
		984	# try to write data immediately
		985	$cb->() unless $self->{autocork};
		986
		987	# if still data left in wbuf, we need to poll
		988	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		989	if length $self->{wbuf};
		990
		991	if (
		992	defined $self->{wbuf_max}
		993	&& $self->{wbuf_max} < length $self->{wbuf}
		994	) {
		995	$self->error (Errno::ENOSPC, 1), return;
		996	}
		997	};
		998	}
		999
		1000	our %WH;
		1001
		1002	# deprecated
		1003	sub register_write_type($$) {
		1004	$WH{$_[0]} = $_[1];
		1005	}
		1006
		1007	sub push_write {
		1008	my $self = shift;
		1009
		1010	if (@_ > 1) {
		1011	my $type = shift;
		1012
		1013	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
		1014	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
		1015	->($self, @_);
		1016	}
		1017
		1018	# we downgrade here to avoid hard-to-track-down bugs,
		1019	# and diagnose the problem earlier and better.
		1020
		1021	if ($self->{tls}) {
		1022	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		1023	&_dotls ($self) if $self->{fh};
		1024	} else {
		1025	utf8::downgrade $self->{wbuf} .= $_[0];
		1026	$self->_drain_wbuf if $self->{fh};
		1027	}
		1028	}
		1029
		1030	=item $handle->push_write (type => @args)
		1031
		1032	Instead of formatting your data yourself, you can also let this module
		1033	do the job by specifying a type and type-specific arguments. You
		1034	can also specify the (fully qualified) name of a package, in which
		1035	case AnyEvent tries to load the package and then expects to find the
		1036	C<anyevent_write_type> function inside (see "custom write types", below).
		1037
		1038	Predefined types are (if you have ideas for additional types, feel free to
		1039	drop by and tell us):
		1040
		1041	=over 4
		1042
		1043	=item netstring => $string
		1044
		1045	Formats the given value as netstring
		1046	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		1047
		1048	=cut
		1049
		1050	register_write_type netstring => sub {
		1051	my ($self, $string) = @_;
		1052
		1053	(length $string) . ":$string,"
		1054	};
		1055
		1056	=item packstring => $format, $data
		1057
		1058	An octet string prefixed with an encoded length. The encoding C<$format>
		1059	uses the same format as a Perl C<pack> format, but must specify a single
		1060	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1061	optional C<!>, C<< < >> or C<< > >> modifier).
		1062
		1063	=cut
		1064
		1065	register_write_type packstring => sub {
		1066	my ($self, $format, $string) = @_;
		1067
		1068	pack "$format/a*", $string
		1069	};
		1070
		1071	=item json => $array_or_hashref
		1072
		1073	Encodes the given hash or array reference into a JSON object. Unless you
		1074	provide your own JSON object, this means it will be encoded to JSON text
		1075	in UTF-8.
		1076
		1077	The default encoder might or might not handle every type of JSON value -
		1078	it might be limited to arrays and objects for security reasons. See the
		1079	C<json> constructor attribute for more details.
		1080
		1081	JSON objects (and arrays) are self-delimiting, so if you only use arrays
		1082	and hashes, you can write JSON at one end of a handle and read them at the
		1083	other end without using any additional framing.
		1084
		1085	The JSON text generated by the default encoder is guaranteed not to
		1086	contain any newlines: While this module doesn't need delimiters after or
		1087	between JSON texts to be able to read them, many other languages depend on
		1088	them.
		1089
		1090	A simple RPC protocol that interoperates easily with other languages is
		1091	to send JSON arrays (or objects, although arrays are usually the better
		1092	choice as they mimic how function argument passing works) and a newline
		1093	after each JSON text:
		1094
		1095	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		1096	$handle->push_write ("\012");
		1097
		1098	An AnyEvent::Handle receiver would simply use the C<json> read type and
		1099	rely on the fact that the newline will be skipped as leading whitespace:
		1100
		1101	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1102
		1103	Other languages could read single lines terminated by a newline and pass
		1104	this line into their JSON decoder of choice.
		1105
		1106	=item cbor => $perl_scalar
		1107
		1108	Encodes the given scalar into a CBOR value. Unless you provide your own
		1109	L<CBOR::XS> object, this means it will be encoded to a CBOR string not
		1110	using any extensions, if possible.
		1111
		1112	CBOR values are self-delimiting, so you can write CBOR at one end of
		1113	a handle and read them at the other end without using any additional
		1114	framing.
		1115
		1116	A simple nd very very fast RPC protocol that interoperates with
		1117	other languages is to send CBOR and receive CBOR values (arrays are
		1118	recommended):
		1119
		1120	$handle->push_write (cbor => ["method", "arg1", "arg2"]); # whatever
		1121
		1122	An AnyEvent::Handle receiver would simply use the C<cbor> read type:
		1123
		1124	$handle->push_read (cbor => sub { my $array = $_[1]; ... });
		1125
		1126	=cut
		1127
		1128	sub json_coder() {
		1129	eval { require JSON::XS; JSON::XS->new->utf8 }
		1130	|| do { require JSON::PP; JSON::PP->new->utf8 }
		1131	}
		1132
		1133	register_write_type json => sub {
		1134	my ($self, $ref) = @_;
		1135
		1136	($self->{json} ||= json_coder)
		1137	->encode ($ref)
		1138	};
		1139
		1140	sub cbor_coder() {
		1141	require CBOR::XS;
		1142	CBOR::XS->new
		1143	}
		1144
		1145	register_write_type cbor => sub {
		1146	my ($self, $scalar) = @_;
		1147
		1148	($self->{cbor} ||= cbor_coder)
		1149	->encode ($scalar)
		1150	};
		1151
		1152	=item storable => $reference
		1153
		1154	Freezes the given reference using L<Storable> and writes it to the
		1155	handle. Uses the C<nfreeze> format.
		1156
		1157	=cut
		1158
		1159	register_write_type storable => sub {
		1160	my ($self, $ref) = @_;
		1161
		1162	require Storable unless $Storable::VERSION;
		1163
		1164	pack "w/a*", Storable::nfreeze ($ref)
		1165	};
		1166
		1167	=back
		1168
		1169	=item $handle->push_shutdown
		1170
		1171	Sometimes you know you want to close the socket after writing your data
		1172	before it was actually written. One way to do that is to replace your
		1173	C<on_drain> handler by a callback that shuts down the socket (and set
		1174	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1175	replaces the C<on_drain> callback with:
		1176
		1177	sub { shutdown $_[0]{fh}, 1 }
		1178
		1179	This simply shuts down the write side and signals an EOF condition to the
		1180	the peer.
		1181
		1182	You can rely on the normal read queue and C<on_eof> handling
		1183	afterwards. This is the cleanest way to close a connection.
		1184
		1185	This method may invoke callbacks (and therefore the handle might be
		1186	destroyed after it returns).
		1187
		1188	=cut
		1189
		1190	sub push_shutdown {
		1191	my ($self) = @_;
		1192
		1193	delete $self->{low_water_mark};
		1194	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1195	}
		1196
		1197	=item custom write types - Package::anyevent_write_type $handle, @args
		1198
		1199	Instead of one of the predefined types, you can also specify the name of
		1200	a package. AnyEvent will try to load the package and then expects to find
		1201	a function named C<anyevent_write_type> inside. If it isn't found, it
		1202	progressively tries to load the parent package until it either finds the
		1203	function (good) or runs out of packages (bad).
		1204
		1205	Whenever the given C<type> is used, C<push_write> will the function with
		1206	the handle object and the remaining arguments.
		1207
		1208	The function is supposed to return a single octet string that will be
		1209	appended to the write buffer, so you can mentally treat this function as a
		1210	"arguments to on-the-wire-format" converter.
		1211
		1212	Example: implement a custom write type C<join> that joins the remaining
		1213	arguments using the first one.
		1214
		1215	$handle->push_write (My::Type => " ", 1,2,3);
		1216
		1217	# uses the following package, which can be defined in the "My::Type" or in
		1218	# the "My" modules to be auto-loaded, or just about anywhere when the
		1219	# My::Type::anyevent_write_type is defined before invoking it.
		1220
		1221	package My::Type;
		1222
		1223	sub anyevent_write_type {
		1224	my ($handle, $delim, @args) = @_;
		1225
		1226	join $delim, @args
		1227	}
		1228
		1229	=cut
		1230
		1231	#############################################################################
		1232
		1233	=back
		1234
		1235	=head2 READ QUEUE
		1236
		1237	AnyEvent::Handle manages two queues per handle, one for writing and one
		1238	for reading.
		1239
		1240	The read queue is more complex than the write queue. It can be used in two
		1241	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		1242	a queue.
		1243
		1244	In the simple case, you just install an C<on_read> callback and whenever
		1245	new data arrives, it will be called. You can then remove some data (if
		1246	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
		1247	leave the data there if you want to accumulate more (e.g. when only a
		1248	partial message has been received so far), or change the read queue with
		1249	e.g. C<push_read>.
		1250
		1251	In the more complex case, you want to queue multiple callbacks. In this
		1252	case, AnyEvent::Handle will call the first queued callback each time new
		1253	data arrives (also the first time it is queued) and remove it when it has
		1254	done its job (see C<push_read>, below).
		1255
		1256	This way you can, for example, push three line-reads, followed by reading
		1257	a chunk of data, and AnyEvent::Handle will execute them in order.
		1258
		1259	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		1260	the specified number of bytes which give an XML datagram.
		1261
		1262	# in the default state, expect some header bytes
		1263	$handle->on_read (sub {
		1264	# some data is here, now queue the length-header-read (4 octets)
		1265	shift->unshift_read (chunk => 4, sub {
		1266	# header arrived, decode
		1267	my $len = unpack "N", $_[1];
		1268
		1269	# now read the payload
		1270	shift->unshift_read (chunk => $len, sub {
		1271	my $xml = $_[1];
		1272	# handle xml
		1273	});
		1274	});
		1275	});
		1276
		1277	Example 2: Implement a client for a protocol that replies either with "OK"
		1278	and another line or "ERROR" for the first request that is sent, and 64
		1279	bytes for the second request. Due to the availability of a queue, we can
		1280	just pipeline sending both requests and manipulate the queue as necessary
		1281	in the callbacks.
		1282
		1283	When the first callback is called and sees an "OK" response, it will
		1284	C<unshift> another line-read. This line-read will be queued I<before> the
		1285	64-byte chunk callback.
		1286
		1287	# request one, returns either "OK + extra line" or "ERROR"
		1288	$handle->push_write ("request 1\015\012");
		1289
		1290	# we expect "ERROR" or "OK" as response, so push a line read
		1291	$handle->push_read (line => sub {
		1292	# if we got an "OK", we have to _prepend_ another line,
		1293	# so it will be read before the second request reads its 64 bytes
		1294	# which are already in the queue when this callback is called
		1295	# we don't do this in case we got an error
		1296	if ($_[1] eq "OK") {
		1297	$_[0]->unshift_read (line => sub {
		1298	my $response = $_[1];
		1299	...
		1300	});
38	}	1301	}
39	});	1302	});
40		1303
41	# or use the constructor to pass the callback:	1304	# request two, simply returns 64 octets
		1305	$handle->push_write ("request 2\015\012");
42		1306
43	my $ae_fh2 =	1307	# simply read 64 bytes, always
44	AnyEvent::Handle->new (	1308	$handle->push_read (chunk => 64, sub {
45	fh => \*STDIN,	1309	my $response = $_[1];
46	on_eof => sub {	1310	...
47	$cv->broadcast;	1311	});
48	},	1312
49	on_readline => sub {	1313	=over 4
50	my ($ae_fh, @lines) = @_;	1314
51	for (@lines) {	1315	=cut
52	chomp;	1316
53	print "Line: $_";	1317	sub _drain_rbuf {
		1318	my ($self) = @_;
		1319
		1320	# avoid recursion
		1321	return if $self->{_skip_drain_rbuf};
		1322	local $self->{_skip_drain_rbuf} = 1;
		1323
		1324	while () {
		1325	# we need to use a separate tls read buffer, as we must not receive data while
		1326	# we are draining the buffer, and this can only happen with TLS.
		1327	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1328	if exists $self->{_tls_rbuf};
		1329
		1330	my $len = length $self->{rbuf};
		1331
		1332	if (my $cb = shift @{ $self->{_queue} }) {
		1333	unless ($cb->($self)) {
		1334	# no progress can be made
		1335	# (not enough data and no data forthcoming)
		1336	$self->error (Errno::EPIPE, 1), return
		1337	if $self->{_eof};
		1338
		1339	unshift @{ $self->{_queue} }, $cb;
54	}	1340	last;
55	}	1341	}
56	);
57
58	$cv->wait;
59
60	=head1 DESCRIPTION
61
62	This module is a helper module to make it easier to do non-blocking I/O
63	on filehandles (and sockets, see L<AnyEvent::Socket>).
64
65	The event loop is provided by L<AnyEvent>.
66
67	=head1 METHODS
68
69	=over 4
70
71	=item B<new (%args)>
72
73	The constructor has these arguments:
74
75	=over 4
76
77	=item fh => $filehandle
78
79	The filehandle this L<AnyEvent::Handle> object will operate on.
80
81	NOTE: The filehandle will be set to non-blocking.
82
83	=item read_block_size => $size
84
85	The default read block size use for reads via the C<on_read>
86	method.
87
88	=item on_read => $cb
89
90	=item on_eof => $cb
91
92	=item on_error => $cb
93
94	These are shortcuts, that will call the corresponding method and set the callback to C<$cb>.
95
96	=item on_readline => $cb
97
98	The C<readlines> method is called with the default seperator and C<$cb> as callback
99	for you.
100
101	=back
102
103	=cut
104
105	sub new {
106	my $this = shift;
107	my $class = ref($this) || $this;
108	my $self = {
109	read_block_size => 4096,
110	rbuf => '',
111	@_
112	};
113	bless $self, $class;
114
115	$self->{fh}->blocking (0) if $self->{fh};
116
117	if ($self->{on_read}) {
118	$self->on_read ($self->{on_read});
119
120	} elsif ($self->{on_readline}) {	1342	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	1343	last unless $len;
122		1344
		1345	$self->{on_read}($self);
		1346
		1347	if (
		1348	$len == length $self->{rbuf} # if no data has been consumed
		1349	&& !@{ $self->{_queue} } # and the queue is still empty
		1350	&& $self->{on_read} # but we still have on_read
		1351	) {
		1352	# no further data will arrive
		1353	# so no progress can be made
		1354	$self->error (Errno::EPIPE, 1), return
		1355	if $self->{_eof};
		1356
		1357	last; # more data might arrive
		1358	}
		1359	} else {
		1360	# read side becomes idle
		1361	delete $self->{_rw} unless $self->{tls};
		1362	last;
		1363	}
		1364	}
		1365
123	} elsif ($self->{on_eof}) {	1366	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});	1367	$self->{on_eof}
		1368	? $self->{on_eof}($self)
		1369	: $self->error (0, 1, "Unexpected end-of-file");
125		1370
126	} elsif ($self->{on_error}) {	1371	return;
127	$self->on_eof ($self->{on_error});
128	}	1372	}
129		1373
130	return $self	1374	if (
131	}	1375	defined $self->{rbuf_max}
		1376	&& $self->{rbuf_max} < length $self->{rbuf}
		1377	) {
		1378	$self->error (Errno::ENOSPC, 1), return;
		1379	}
132		1380
133	=item B<fh>	1381	# may need to restart read watcher
		1382	unless ($self->{_rw}) {
		1383	$self->start_read
		1384	if $self->{on_read} || @{ $self->{_queue} };
		1385	}
		1386	}
134		1387
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	1388	=item $handle->on_read ($cb)
136		1389
137	=cut	1390	This replaces the currently set C<on_read> callback, or clears it (when
		1391	the new callback is C<undef>). See the description of C<on_read> in the
		1392	constructor.
138		1393
139	sub fh { $_[0]->{fh} }	1394	This method may invoke callbacks (and therefore the handle might be
140		1395	destroyed after it returns).
141	=item B<on_read ($callback)>
142
143	This method installs a C<$callback> that will be called
144	when new data arrived. You can access the read buffer via the C<rbuf>
145	method (see below).
146
147	The first argument of the C<$callback> will be the L<AnyEvent::Handle> object.
148		1396
149	=cut	1397	=cut
150		1398
151	sub on_read {	1399	sub on_read {
152	my ($self, $cb) = @_;	1400	my ($self, $cb) = @_;
		1401
153	$self->{on_read} = $cb;	1402	$self->{on_read} = $cb;
		1403	$self->_drain_rbuf if $cb;
		1404	}
154		1405
155	unless (defined $self->{on_read}) {	1406	=item $handle->rbuf
156	delete $self->{on_read_w};	1407
		1408	Returns the read buffer (as a modifiable lvalue). You can also access the
		1409	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1410	much faster, and no less clean).
		1411
		1412	The only operation allowed on the read buffer (apart from looking at it)
		1413	is removing data from its beginning. Otherwise modifying or appending to
		1414	it is not allowed and will lead to hard-to-track-down bugs.
		1415
		1416	NOTE: The read buffer should only be used or modified in the C<on_read>
		1417	callback or when C<push_read> or C<unshift_read> are used with a single
		1418	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1419	will manage the read buffer on their own.
		1420
		1421	=cut
		1422
		1423	sub rbuf : lvalue {
		1424	$_[0]{rbuf}
		1425	}
		1426
		1427	=item $handle->push_read ($cb)
		1428
		1429	=item $handle->unshift_read ($cb)
		1430
		1431	Append the given callback to the end of the queue (C<push_read>) or
		1432	prepend it (C<unshift_read>).
		1433
		1434	The callback is called each time some additional read data arrives.
		1435
		1436	It must check whether enough data is in the read buffer already.
		1437
		1438	If not enough data is available, it must return the empty list or a false
		1439	value, in which case it will be called repeatedly until enough data is
		1440	available (or an error condition is detected).
		1441
		1442	If enough data was available, then the callback must remove all data it is
		1443	interested in (which can be none at all) and return a true value. After returning
		1444	true, it will be removed from the queue.
		1445
		1446	These methods may invoke callbacks (and therefore the handle might be
		1447	destroyed after it returns).
		1448
		1449	=cut
		1450
		1451	our %RH;
		1452
		1453	sub register_read_type($$) {
		1454	$RH{$_[0]} = $_[1];
		1455	}
		1456
		1457	sub push_read {
		1458	my $self = shift;
		1459	my $cb = pop;
		1460
		1461	if (@_) {
		1462	my $type = shift;
		1463
		1464	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1465	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
		1466	->($self, $cb, @_);
		1467	}
		1468
		1469	push @{ $self->{_queue} }, $cb;
		1470	$self->_drain_rbuf;
		1471	}
		1472
		1473	sub unshift_read {
		1474	my $self = shift;
		1475	my $cb = pop;
		1476
		1477	if (@_) {
		1478	my $type = shift;
		1479
		1480	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1481	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
		1482	->($self, $cb, @_);
		1483	}
		1484
		1485	unshift @{ $self->{_queue} }, $cb;
		1486	$self->_drain_rbuf;
		1487	}
		1488
		1489	=item $handle->push_read (type => @args, $cb)
		1490
		1491	=item $handle->unshift_read (type => @args, $cb)
		1492
		1493	Instead of providing a callback that parses the data itself you can chose
		1494	between a number of predefined parsing formats, for chunks of data, lines
		1495	etc. You can also specify the (fully qualified) name of a package, in
		1496	which case AnyEvent tries to load the package and then expects to find the
		1497	C<anyevent_read_type> function inside (see "custom read types", below).
		1498
		1499	Predefined types are (if you have ideas for additional types, feel free to
		1500	drop by and tell us):
		1501
		1502	=over 4
		1503
		1504	=item chunk => $octets, $cb->($handle, $data)
		1505
		1506	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1507	data read to the callback. The callback will never be called with less
		1508	data.
		1509
		1510	Example: read 2 bytes.
		1511
		1512	$handle->push_read (chunk => 2, sub {
		1513	say "yay " . unpack "H*", $_[1];
		1514	});
		1515
		1516	=cut
		1517
		1518	register_read_type chunk => sub {
		1519	my ($self, $cb, $len) = @_;
		1520
		1521	sub {
		1522	$len <= length $_[0]{rbuf} or return;
		1523	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		1524	1
		1525	}
		1526	};
		1527
		1528	=item line => [$eol, ]$cb->($handle, $line, $eol)
		1529
		1530	The callback will be called only once a full line (including the end of
		1531	line marker, C<$eol>) has been read. This line (excluding the end of line
		1532	marker) will be passed to the callback as second argument (C<$line>), and
		1533	the end of line marker as the third argument (C<$eol>).
		1534
		1535	The end of line marker, C<$eol>, can be either a string, in which case it
		1536	will be interpreted as a fixed record end marker, or it can be a regex
		1537	object (e.g. created by C<qr>), in which case it is interpreted as a
		1538	regular expression.
		1539
		1540	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		1541	undef), then C<qr|\015?\012|> is used (which is good for most internet
		1542	protocols).
		1543
		1544	Partial lines at the end of the stream will never be returned, as they are
		1545	not marked by the end of line marker.
		1546
		1547	=cut
		1548
		1549	register_read_type line => sub {
		1550	my ($self, $cb, $eol) = @_;
		1551
		1552	if (@_ < 3) {
		1553	# this is faster then the generic code below
		1554	sub {
		1555	(my $pos = index $_[0]{rbuf}, "\012") >= 0
		1556	or return;
		1557
		1558	(my $str = substr $_[0]{rbuf}, 0, $pos + 1, "") =~ s/(\015?\012)\Z// or die;
		1559	$cb->($_[0], $str, "$1");
		1560	1
		1561	}
		1562	} else {
		1563	$eol = quotemeta $eol unless ref $eol;
		1564	$eol = qr|^(.*?)($eol)|s;
		1565
		1566	sub {
		1567	$_[0]{rbuf} =~ s/$eol// or return;
		1568
		1569	$cb->($_[0], "$1", "$2");
		1570	1
		1571	}
		1572	}
		1573	};
		1574
		1575	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1576
		1577	Makes a regex match against the regex object C<$accept> and returns
		1578	everything up to and including the match. All the usual regex variables
		1579	($1, %+ etc.) from the regex match are available in the callback.
		1580
		1581	Example: read a single line terminated by '\n'.
		1582
		1583	$handle->push_read (regex => qr<\n>, sub { ... });
		1584
		1585	If C<$reject> is given and not undef, then it determines when the data is
		1586	to be rejected: it is matched against the data when the C<$accept> regex
		1587	does not match and generates an C<EBADMSG> error when it matches. This is
		1588	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1589	receive buffer overflow).
		1590
		1591	Example: expect a single decimal number followed by whitespace, reject
		1592	anything else (not the use of an anchor).
		1593
		1594	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1595
		1596	If C<$skip> is given and not C<undef>, then it will be matched against
		1597	the receive buffer when neither C<$accept> nor C<$reject> match,
		1598	and everything preceding and including the match will be accepted
		1599	unconditionally. This is useful to skip large amounts of data that you
		1600	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1601	have to start matching from the beginning. This is purely an optimisation
		1602	and is usually worth it only when you expect more than a few kilobytes.
		1603
		1604	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1605	expect the header to be very large (it isn't in practice, but...), we use
		1606	a skip regex to skip initial portions. The skip regex is tricky in that
		1607	it only accepts something not ending in either \015 or \012, as these are
		1608	required for the accept regex.
		1609
		1610	$handle->push_read (regex =>
		1611	qr<\015\012\015\012>,
		1612	undef, # no reject
		1613	qr<^.*[^\015\012]>,
		1614	sub { ... });
		1615
		1616	=cut
		1617
		1618	register_read_type regex => sub {
		1619	my ($self, $cb, $accept, $reject, $skip) = @_;
		1620
		1621	my $data;
		1622	my $rbuf = \$self->{rbuf};
		1623
		1624	sub {
		1625	# accept
		1626	if ($$rbuf =~ $accept) {
		1627	$data .= substr $$rbuf, 0, $+[0], "";
		1628	$cb->($_[0], $data);
		1629	return 1;
		1630	}
		1631
		1632	# reject
		1633	if ($reject && $$rbuf =~ $reject) {
		1634	$_[0]->error (Errno::EBADMSG);
		1635	}
		1636
		1637	# skip
		1638	if ($skip && $$rbuf =~ $skip) {
		1639	$data .= substr $$rbuf, 0, $+[0], "";
		1640	}
		1641
		1642	()
		1643	}
		1644	};
		1645
		1646	=item netstring => $cb->($handle, $string)
		1647
		1648	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1649
		1650	Throws an error with C<$!> set to EBADMSG on format violations.
		1651
		1652	=cut
		1653
		1654	register_read_type netstring => sub {
		1655	my ($self, $cb) = @_;
		1656
		1657	sub {
		1658	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1659	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1660	$_[0]->error (Errno::EBADMSG);
		1661	}
157	return;	1662	return;
		1663	}
		1664
		1665	my $len = $1;
		1666
		1667	$_[0]->unshift_read (chunk => $len, sub {
		1668	my $string = $_[1];
		1669	$_[0]->unshift_read (chunk => 1, sub {
		1670	if ($_[1] eq ",") {
		1671	$cb->($_[0], $string);
		1672	} else {
		1673	$_[0]->error (Errno::EBADMSG);
		1674	}
		1675	});
		1676	});
		1677
		1678	1
		1679	}
		1680	};
		1681
		1682	=item packstring => $format, $cb->($handle, $string)
		1683
		1684	An octet string prefixed with an encoded length. The encoding C<$format>
		1685	uses the same format as a Perl C<pack> format, but must specify a single
		1686	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1687	optional C<!>, C<< < >> or C<< > >> modifier).
		1688
		1689	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1690	EPP uses a prefix of C<N> (4 octtes).
		1691
		1692	Example: read a block of data prefixed by its length in BER-encoded
		1693	format (very efficient).
		1694
		1695	$handle->push_read (packstring => "w", sub {
		1696	my ($handle, $data) = @_;
		1697	});
		1698
		1699	=cut
		1700
		1701	register_read_type packstring => sub {
		1702	my ($self, $cb, $format) = @_;
		1703
		1704	sub {
		1705	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1706	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1707	or return;
		1708
		1709	$format = length pack $format, $len;
		1710
		1711	# bypass unshift if we already have the remaining chunk
		1712	if ($format + $len <= length $_[0]{rbuf}) {
		1713	my $data = substr $_[0]{rbuf}, $format, $len;
		1714	substr $_[0]{rbuf}, 0, $format + $len, "";
		1715	$cb->($_[0], $data);
		1716	} else {
		1717	# remove prefix
		1718	substr $_[0]{rbuf}, 0, $format, "";
		1719
		1720	# read remaining chunk
		1721	$_[0]->unshift_read (chunk => $len, $cb);
		1722	}
		1723
		1724	1
		1725	}
		1726	};
		1727
		1728	=item json => $cb->($handle, $hash_or_arrayref)
		1729
		1730	Reads a JSON object or array, decodes it and passes it to the
		1731	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1732
		1733	If a C<json> object was passed to the constructor, then that will be
		1734	used for the final decode, otherwise it will create a L<JSON::XS> or
		1735	L<JSON::PP> coder object expecting UTF-8.
		1736
		1737	This read type uses the incremental parser available with JSON version
		1738	2.09 (and JSON::XS version 2.2) and above.
		1739
		1740	Since JSON texts are fully self-delimiting, the C<json> read and write
		1741	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1742	the C<json> write type description, above, for an actual example.
		1743
		1744	=cut
		1745
		1746	register_read_type json => sub {
		1747	my ($self, $cb) = @_;
		1748
		1749	my $json = $self->{json} ||= json_coder;
		1750
		1751	my $data;
		1752
		1753	sub {
		1754	my $ref = eval { $json->incr_parse ($_[0]{rbuf}) };
		1755
		1756	if ($ref) {
		1757	$_[0]{rbuf} = $json->incr_text;
		1758	$json->incr_text = "";
		1759	$cb->($_[0], $ref);
		1760
		1761	1
		1762	} elsif ($@) {
		1763	# error case
		1764	$json->incr_skip;
		1765
		1766	$_[0]{rbuf} = $json->incr_text;
		1767	$json->incr_text = "";
		1768
		1769	$_[0]->error (Errno::EBADMSG);
		1770
		1771	()
		1772	} else {
		1773	$_[0]{rbuf} = "";
		1774
		1775	()
		1776	}
		1777	}
		1778	};
		1779
		1780	=item cbor => $cb->($handle, $scalar)
		1781
		1782	Reads a CBOR value, decodes it and passes it to the callback. When a parse
		1783	error occurs, an C<EBADMSG> error will be raised.
		1784
		1785	If a L<CBOR::XS> object was passed to the constructor, then that will be
		1786	used for the final decode, otherwise it will create a CBOR coder without
		1787	enabling any options.
		1788
		1789	You have to provide a dependency to L<CBOR::XS> on your own: this module
		1790	will load the L<CBOR::XS> module, but AnyEvent does not depend on it
		1791	itself.
		1792
		1793	Since CBOR values are fully self-delimiting, the C<cbor> read and write
		1794	types are an ideal simple RPC protocol: just exchange CBOR datagrams. See
		1795	the C<cbor> write type description, above, for an actual example.
		1796
		1797	=cut
		1798
		1799	register_read_type cbor => sub {
		1800	my ($self, $cb) = @_;
		1801
		1802	my $cbor = $self->{cbor} ||= cbor_coder;
		1803
		1804	my $data;
		1805
		1806	sub {
		1807	my (@value) = eval { $cbor->incr_parse ($_[0]{rbuf}) };
		1808
		1809	if (@value) {
		1810	$cb->($_[0], @value);
		1811
		1812	1
		1813	} elsif ($@) {
		1814	# error case
		1815	$cbor->incr_reset;
		1816
		1817	$_[0]->error (Errno::EBADMSG);
		1818
		1819	()
		1820	} else {
		1821	()
		1822	}
		1823	}
		1824	};
		1825
		1826	=item storable => $cb->($handle, $ref)
		1827
		1828	Deserialises a L<Storable> frozen representation as written by the
		1829	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1830	data).
		1831
		1832	Raises C<EBADMSG> error if the data could not be decoded.
		1833
		1834	=cut
		1835
		1836	register_read_type storable => sub {
		1837	my ($self, $cb) = @_;
		1838
		1839	require Storable unless $Storable::VERSION;
		1840
		1841	sub {
		1842	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1843	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1844	or return;
		1845
		1846	my $format = length pack "w", $len;
		1847
		1848	# bypass unshift if we already have the remaining chunk
		1849	if ($format + $len <= length $_[0]{rbuf}) {
		1850	my $data = substr $_[0]{rbuf}, $format, $len;
		1851	substr $_[0]{rbuf}, 0, $format + $len, "";
		1852
		1853	eval { $cb->($_[0], Storable::thaw ($data)); 1 }
		1854	or return $_[0]->error (Errno::EBADMSG);
		1855	} else {
		1856	# remove prefix
		1857	substr $_[0]{rbuf}, 0, $format, "";
		1858
		1859	# read remaining chunk
		1860	$_[0]->unshift_read (chunk => $len, sub {
		1861	eval { $cb->($_[0], Storable::thaw ($_[1])); 1 }
		1862	or $_[0]->error (Errno::EBADMSG);
		1863	});
		1864	}
		1865
		1866	1
		1867	}
		1868	};
		1869
		1870	=item tls_detect => $cb->($handle, $detect, $major, $minor)
		1871
		1872	Checks the input stream for a valid SSL or TLS handshake TLSPaintext
		1873	record without consuming anything. Only SSL version 3 or higher
		1874	is handled, up to the fictituous protocol 4.x (but both SSL3+ and
		1875	SSL2-compatible framing is supported).
		1876
		1877	If it detects that the input data is likely TLS, it calls the callback
		1878	with a true value for C<$detect> and the (on-wire) TLS version as second
		1879	and third argument (C<$major> is C<3>, and C<$minor> is 0..4 for SSL
		1880	3.0, TLS 1.0, 1.1, 1.2 and 1.3, respectively). If it detects the input
		1881	to be definitely not TLS, it calls the callback with a false value for
		1882	C<$detect>.
		1883
		1884	The callback could use this information to decide whether or not to start
		1885	TLS negotiation.
		1886
		1887	In all cases the data read so far is passed to the following read
		1888	handlers.
		1889
		1890	Usually you want to use the C<tls_autostart> read type instead.
		1891
		1892	If you want to design a protocol that works in the presence of TLS
		1893	dtection, make sure that any non-TLS data doesn't start with the octet 22
		1894	(ASCII SYN, 16 hex) or 128-255 (i.e. highest bit set). The checks this
		1895	read type does are a bit more strict, but might losen in the future to
		1896	accomodate protocol changes.
		1897
		1898	This read type does not rely on L<AnyEvent::TLS> (and thus, not on
		1899	L<Net::SSLeay>).
		1900
		1901	=item tls_autostart => [$tls_ctx, ]$tls
		1902
		1903	Tries to detect a valid SSL or TLS handshake. If one is detected, it tries
		1904	to start tls by calling C<starttls> with the given arguments.
		1905
		1906	In practice, C<$tls> must be C<accept>, or a Net::SSLeay context that has
		1907	been configured to accept, as servers do not normally send a handshake on
		1908	their own and ths cannot be detected in this way.
		1909
		1910	See C<tls_detect> above for more details.
		1911
		1912	Example: give the client a chance to start TLS before accepting a text
		1913	line.
		1914
		1915	$hdl->push_read (tls_autostart => "accept");
		1916	$hdl->push_read (line => sub {
		1917	print "received ", ($_[0]{tls} ? "encrypted" : "cleartext"), " <$_[1]>\n";
		1918	});
		1919
		1920	=cut
		1921
		1922	register_read_type tls_detect => sub {
		1923	my ($self, $cb) = @_;
		1924
		1925	sub {
		1926	# this regex matches a full or partial tls record
		1927	if (
		1928	# ssl3+: type(22=handshake) major(=3) minor(any) length_hi
		1929	$self->{rbuf} =~ /^(?:\z| \x16 (\z| [\x03\x04] (?:\z| . (?:\z| [\x00-\x40] ))))/xs
		1930	# ssl2 comapatible: len_hi len_lo type(1) major minor dummy(forlength)
		1931	or $self->{rbuf} =~ /^(?:\z| [\x80-\xff] (?:\z| . (?:\z| \x01 (\z| [\x03\x04] (?:\z| . (?:\z| . ))))))/xs
		1932	) {
		1933	return if 3 != length $1; # partial match, can't decide yet
		1934
		1935	# full match, valid TLS record
		1936	my ($major, $minor) = unpack "CC", $1;
		1937	$cb->($self, "accept", $major, $minor);
		1938	} else {
		1939	# mismatch == guaranteed not TLS
		1940	$cb->($self, undef);
		1941	}
		1942
		1943	1
		1944	}
		1945	};
		1946
		1947	register_read_type tls_autostart => sub {
		1948	my ($self, @tls) = @_;
		1949
		1950	$RH{tls_detect}($self, sub {
		1951	return unless $_[1];
		1952	$_[0]->starttls (@tls);
158	}	1953	})
159		1954	};
160	$self->{on_read_w} =	1955
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1956	=back
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1957
163	my $rbuf_len = length $self->{rbuf};	1958	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
164	my $l;	1959
		1960	Instead of one of the predefined types, you can also specify the name
		1961	of a package. AnyEvent will try to load the package and then expects to
		1962	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1963	progressively tries to load the parent package until it either finds the
		1964	function (good) or runs out of packages (bad).
		1965
		1966	Whenever this type is used, C<push_read> will invoke the function with the
		1967	handle object, the original callback and the remaining arguments.
		1968
		1969	The function is supposed to return a callback (usually a closure) that
		1970	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1971	mentally treat the function as a "configurable read type to read callback"
		1972	converter.
		1973
		1974	It should invoke the original callback when it is done reading (remember
		1975	to pass C<$handle> as first argument as all other callbacks do that,
		1976	although there is no strict requirement on this).
		1977
		1978	For examples, see the source of this module (F<perldoc -m
		1979	AnyEvent::Handle>, search for C<register_read_type>)).
		1980
		1981	=item $handle->stop_read
		1982
		1983	=item $handle->start_read
		1984
		1985	In rare cases you actually do not want to read anything from the
		1986	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1987	any queued callbacks will be executed then. To start reading again, call
		1988	C<start_read>.
		1989
		1990	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1991	you change the C<on_read> callback or push/unshift a read callback, and it
		1992	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1993	there are any read requests in the queue.
		1994
		1995	In older versions of this module (<= 5.3), these methods had no effect,
		1996	as TLS does not support half-duplex connections. In current versions they
		1997	work as expected, as this behaviour is required to avoid certain resource
		1998	attacks, where the program would be forced to read (and buffer) arbitrary
		1999	amounts of data before being able to send some data. The drawback is that
		2000	some readings of the the SSL/TLS specifications basically require this
		2001	attack to be working, as SSL/TLS implementations might stall sending data
		2002	during a rehandshake.
		2003
		2004	As a guideline, during the initial handshake, you should not stop reading,
		2005	and as a client, it might cause problems, depending on your application.
		2006
		2007	=cut
		2008
		2009	sub stop_read {
		2010	my ($self) = @_;
		2011
		2012	delete $self->{_rw};
		2013	}
		2014
		2015	sub start_read {
		2016	my ($self) = @_;
		2017
		2018	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
		2019	Scalar::Util::weaken $self;
		2020
		2021	$self->{_rw} = AE::io $self->{fh}, 0, sub {
		2022	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		2023	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
		2024
		2025	if ($len > 0) {
		2026	$self->{_activity} = $self->{_ractivity} = AE::now;
		2027
		2028	if ($self->{tls}) {
		2029	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		2030
		2031	&_dotls ($self);
		2032	} else {
		2033	$self->_drain_rbuf;
		2034	}
		2035
165	if (defined $self->{read_size}) {	2036	if ($len == $self->{read_size}) {
166	$l = sysread $self->{fh}, $self->{rbuf},	2037	$self->{read_size} *= 2;
167	($self->{read_size} - $rbuf_len), $rbuf_len;	2038	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		2039	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		2040	}
		2041
		2042	} elsif (defined $len) {
		2043	delete $self->{_rw};
		2044	$self->{_eof} = 1;
		2045	$self->_drain_rbuf;
		2046
		2047	} elsif ($! != EAGAIN && $! != EINTR && $! != EWOULDBLOCK && $! != WSAEWOULDBLOCK) {
		2048	return $self->error ($!, 1);
		2049	}
		2050	};
		2051	}
		2052	}
		2053
		2054	our $ERROR_SYSCALL;
		2055	our $ERROR_WANT_READ;
		2056
		2057	sub _tls_error {
		2058	my ($self, $err) = @_;
		2059
		2060	return $self->error ($!, 1)
		2061	if $err == Net::SSLeay::ERROR_SYSCALL ();
		2062
		2063	my $err = Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		2064
		2065	# reduce error string to look less scary
		2066	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		2067
		2068	if ($self->{_on_starttls}) {
		2069	(delete $self->{_on_starttls})->($self, undef, $err);
		2070	&_freetls;
		2071	} else {
		2072	&_freetls;
		2073	$self->error (Errno::EPROTO, 1, $err);
		2074	}
		2075	}
		2076
		2077	# poll the write BIO and send the data if applicable
		2078	# also decode read data if possible
		2079	# this is basically our TLS state machine
		2080	# more efficient implementations are possible with openssl,
		2081	# but not with the buggy and incomplete Net::SSLeay.
		2082	sub _dotls {
		2083	my ($self) = @_;
		2084
		2085	my $tmp;
		2086
		2087	while (length $self->{_tls_wbuf}) {
		2088	if (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) <= 0) {
		2089	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		2090
		2091	return $self->_tls_error ($tmp)
		2092	if $tmp != $ERROR_WANT_READ
		2093	&& ($tmp != $ERROR_SYSCALL || $!);
		2094
		2095	last;
		2096	}
		2097
		2098	substr $self->{_tls_wbuf}, 0, $tmp, "";
		2099	}
		2100
		2101	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		2102	unless (length $tmp) {
		2103	$self->{_on_starttls}
		2104	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		2105	&_freetls;
		2106
		2107	if ($self->{on_stoptls}) {
		2108	$self->{on_stoptls}($self);
		2109	return;
168	} else {	2110	} else {
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	2111	# let's treat SSL-eof as we treat normal EOF
170	}
171	#d# warn "READL $l [$self->{rbuf}]\n";
172
173	if (not defined $l) {
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};	2112	delete $self->{_rw};
177
178	} elsif ($l == 0) {
179	$self->{on_eof}->($self) if $self->{on_eof};
180	delete $self->{on_read_w};
181
182	} else {
183	$self->{on_read}->($self);
184	}
185	});
186	}
187
188	=item B<on_error ($callback)>
189
190	Whenever a read or write operation resulted in an error the C<$callback>
191	will be called.
192
193	The first argument of C<$callback> will be the L<AnyEvent::Handle> object itself.
194	The error is given as errno in C<$!>.
195
196	=cut
197
198	sub on_error {
199	$_[0]->{on_error} = $_[1];
200	}
201
202	=item B<on_eof ($callback)>
203
204	Installs the C<$callback> that will be called when the end of file is
205	encountered in a read operation this C<$callback> will be called. The first
206	argument will be the L<AnyEvent::Handle> object itself.
207
208	=cut
209
210	sub on_eof {
211	$_[0]->{on_eof} = $_[1];
212	}
213
214	=item B<rbuf>
215
216	Returns a reference to the read buffer.
217
218	NOTE: The read buffer should only be used or modified if the C<on_read>
219	method is used directly. The C<read> and C<readlines> methods will provide
220	the read data to their callbacks.
221
222	=cut
223
224	sub rbuf : lvalue {
225	$_[0]->{rbuf}
226	}
227
228	=item B<read ($len, $callback)>
229
230	Will read exactly C<$len> bytes from the filehandle and call the C<$callback>
231	if done so. The first argument to the C<$callback> will be the L<AnyEvent::Handle>
232	object itself and the second argument the read data.
233
234	NOTE: This method will override any callbacks installed via the C<on_read> method.
235
236	=cut
237
238	sub read {
239	my ($self, $len, $cb) = @_;
240
241	$self->{read_cb} = $cb;
242	my $old_blk_size = $self->{read_block_size};
243	$self->{read_block_size} = $len;
244
245	$self->on_read (sub {
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";
247
248	if ($len == length $_[0]->{rbuf}) {
249	$_[0]->{read_block_size} = $old_blk_size;
250	$_[0]->on_read (undef);
251	$_[0]->{read_cb}->($_[0], (substr $self->{rbuf}, 0, $len, ''));
252	}
253	});
254	}
255
256	=item B<readlines ($callback)>
257
258	=item B<readlines ($sep, $callback)>
259
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">
261	if C<$sep> is not provided. C<$sep> will be used as "line" seperator.
262
263	The C<$callback> will be called when at least one
264	line could be read. The first argument to the C<$callback> will be the L<AnyEvent::Handle>
265	object itself and the rest of the arguments will be the read lines.
266
267	NOTE: This method will override any callbacks installed via the C<on_read> method.
268
269	=cut
270
271	sub readlines {
272	my ($self, $sep, $cb) = @_;
273
274	if (ref $sep) {
275	$cb = $sep;
276	$sep = "\n";
277
278	} elsif (not defined $sep) {
279	$sep = "\n";
280	}
281
282	my $sep_len = length $sep;
283
284	$self->{on_readline} = $cb;
285
286	$self->on_read (sub {
287	my @lines;
288	my $rb = \$_[0]->{rbuf};
289	my $pos;
290	while (($pos = index ($$rb, $sep)) >= 0) {
291	push @lines, substr $$rb, 0, $pos + $sep_len, '';
292	}
293	$self->{on_readline}->($_[0], @lines);
294	});
295	}
296
297	=item B<write ($data)>
298
299	=item B<write ($callback)>
300
301	=item B<write ($data, $callback)>
302
303	This method will write C<$data> to the filehandle and call the C<$callback>
304	afterwards. If only C<$callback> is provided it will be called when the
305	write buffer becomes empty the next time (or immediately if it already is empty).
306
307	=cut
308
309	sub write {
310	my ($self, $data, $cb) = @_;
311	if (ref $data) { $cb = $data; undef $data }
312	push @{$self->{write_bufs}}, [$data, $cb];
313	$self->_check_writer;
314	}
315
316	sub _check_writer {
317	my ($self) = @_;
318
319	if ($self->{write_w}) {
320	unless ($self->{write_cb}) {
321	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {
322	my $wba = shift @{$self->{write_bufs}};
323	$self->{wbuf} .= $wba->[0];	2113	$self->{_eof} = 1;
324	}	2114	}
325	}	2115	}
326	return;
327	}
328		2116
329	my $wba = shift @{$self->{write_bufs}}	2117	$self->{_tls_rbuf} .= $tmp;
330	or return;	2118	$self->_drain_rbuf;
331		2119	$self->{tls} or return; # tls session might have gone away in callback
332	unless (defined $wba->[0]) {
333	$wba->[1]->($self) if $wba->[1];
334	$self->_check_writer;
335	return;
336	}	2120	}
337		2121
338	$self->{wbuf} = $wba->[0];	2122	$tmp = Net::SSLeay::get_error ($self->{tls}, -1); # -1 is not neccessarily correct, but Net::SSLeay doesn't tell us
339	$self->{write_cb} = $wba->[1];	2123	return $self->_tls_error ($tmp)
		2124	if $tmp != $ERROR_WANT_READ
		2125	&& ($tmp != $ERROR_SYSCALL || $!);
340		2126
341	$self->{write_w} =	2127	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
342	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	2128	$self->{wbuf} .= $tmp;
343	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	2129	$self->_drain_wbuf;
		2130	$self->{tls} or return; # tls session might have gone away in callback
		2131	}
344		2132
345	if (not defined $l) {	2133	$self->{_on_starttls}
346	return if $! == EAGAIN || $! == EINTR;	2134	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
347	delete $self->{write_w};	2135	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
348	$self->{on_error}->($self) if $self->{on_error};	2136	}
349		2137
		2138	=item $handle->starttls ($tls[, $tls_ctx])
		2139
		2140	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		2141	object is created, you can also do that at a later time by calling
		2142	C<starttls>. See the C<tls> constructor argument for general info.
		2143
		2144	Starting TLS is currently an asynchronous operation - when you push some
		2145	write data and then call C<< ->starttls >> then TLS negotiation will start
		2146	immediately, after which the queued write data is then sent. This might
		2147	change in future versions, so best make sure you have no outstanding write
		2148	data when calling this method.
		2149
		2150	The first argument is the same as the C<tls> constructor argument (either
		2151	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		2152
		2153	The second argument is the optional C<AnyEvent::TLS> object that is used
		2154	when AnyEvent::Handle has to create its own TLS connection object, or
		2155	a hash reference with C<< key => value >> pairs that will be used to
		2156	construct a new context.
		2157
		2158	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		2159	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		2160	changed to your liking. Note that the handshake might have already started
		2161	when this function returns.
		2162
		2163	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		2164	handshakes on the same stream. It is best to not attempt to use the
		2165	stream after stopping TLS.
		2166
		2167	This method may invoke callbacks (and therefore the handle might be
		2168	destroyed after it returns).
		2169
		2170	=cut
		2171
		2172	our %TLS_CACHE; #TODO not yet documented, should we?
		2173
		2174	sub starttls {
		2175	my ($self, $tls, $ctx) = @_;
		2176
		2177	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		2178	if $self->{tls};
		2179
		2180	unless (defined $AnyEvent::TLS::VERSION) {
		2181	eval {
		2182	require Net::SSLeay;
		2183	require AnyEvent::TLS;
		2184	1
		2185	} or return $self->error (Errno::EPROTO, 1, "TLS support not available on this system");
		2186	}
		2187
		2188	$self->{tls} = $tls;
		2189	$self->{tls_ctx} = $ctx if @_ > 2;
		2190
		2191	return unless $self->{fh};
		2192
		2193	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		2194	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		2195
		2196	$tls = delete $self->{tls};
		2197	$ctx = $self->{tls_ctx};
		2198
		2199	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		2200
		2201	if ("HASH" eq ref $ctx) {
		2202	if ($ctx->{cache}) {
		2203	my $key = $ctx+0;
		2204	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
350	} else {	2205	} else {
		2206	$ctx = new AnyEvent::TLS %$ctx;
		2207	}
		2208	}
		2209
		2210	$self->{tls_ctx} = $ctx || TLS_CTX ();
		2211	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
		2212
		2213	# basically, this is deep magic (because SSL_read should have the same issues)
		2214	# but the openssl maintainers basically said: "trust us, it just works".
		2215	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		2216	# and mismaintained ssleay-module didn't offer them for a decade or so).
		2217	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		2218	#
		2219	# in short: this is a mess.
		2220	#
		2221	# note that we do not try to keep the length constant between writes as we are required to do.
		2222	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		2223	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		2224	# have identity issues in that area.
		2225	# Net::SSLeay::set_mode ($ssl,
		2226	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		2227	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		2228	Net::SSLeay::set_mode ($tls, 1|2);
		2229
		2230	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		2231	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		2232
		2233	Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
		2234	$self->{rbuf} = "";
		2235
		2236	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
		2237
		2238	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
		2239	if $self->{on_starttls};
		2240
		2241	&_dotls; # need to trigger the initial handshake
		2242	$self->start_read; # make sure we actually do read
		2243	}
		2244
		2245	=item $handle->stoptls
		2246
		2247	Shuts down the SSL connection - this makes a proper EOF handshake by
		2248	sending a close notify to the other side, but since OpenSSL doesn't
		2249	support non-blocking shut downs, it is not guaranteed that you can re-use
		2250	the stream afterwards.
		2251
		2252	This method may invoke callbacks (and therefore the handle might be
		2253	destroyed after it returns).
		2254
		2255	=cut
		2256
		2257	sub stoptls {
		2258	my ($self) = @_;
		2259
		2260	if ($self->{tls} && $self->{fh}) {
		2261	Net::SSLeay::shutdown ($self->{tls});
		2262
		2263	&_dotls;
		2264
		2265	# # we don't give a shit. no, we do, but we can't. no...#d#
		2266	# # we, we... have to use openssl :/#d#
		2267	# &_freetls;#d#
		2268	}
		2269	}
		2270
		2271	sub _freetls {
		2272	my ($self) = @_;
		2273
		2274	return unless $self->{tls};
		2275
		2276	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2277	if $self->{tls} > 0;
		2278
		2279	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		2280	}
		2281
		2282	=item $handle->resettls
		2283
		2284	This rarely-used method simply resets and TLS state on the handle, usually
		2285	causing data loss.
		2286
		2287	One case where it may be useful is when you want to skip over the data in
		2288	the stream but you are not interested in interpreting it, so data loss is
		2289	no concern.
		2290
		2291	=cut
		2292
		2293	*resettls = \&_freetls;
		2294
		2295	sub DESTROY {
		2296	my ($self) = @_;
		2297
		2298	&_freetls;
		2299
		2300	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		2301
		2302	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2303	my $fh = delete $self->{fh};
		2304	my $wbuf = delete $self->{wbuf};
		2305
		2306	my @linger;
		2307
		2308	push @linger, AE::io $fh, 1, sub {
		2309	my $len = syswrite $fh, $wbuf, length $wbuf;
		2310
		2311	if ($len > 0) {
351	substr $self->{wbuf}, 0, $l, '';	2312	substr $wbuf, 0, $len, "";
352		2313	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != EWOULDBLOCK && $! != WSAEWOULDBLOCK)) {
353	if (length ($self->{wbuf}) == 0) {	2314	@linger = (); # end
354	$self->{write_cb}->($self) if $self->{write_cb};
355
356	delete $self->{write_w};
357	delete $self->{wbuf};
358	delete $self->{write_cb};
359
360	$self->_check_writer;
361	}
362	}	2315	}
		2316	};
		2317	push @linger, AE::timer $linger, 0, sub {
		2318	@linger = ();
		2319	};
		2320	}
		2321	}
		2322
		2323	=item $handle->destroy
		2324
		2325	Shuts down the handle object as much as possible - this call ensures that
		2326	no further callbacks will be invoked and as many resources as possible
		2327	will be freed. Any method you will call on the handle object after
		2328	destroying it in this way will be silently ignored (and it will return the
		2329	empty list).
		2330
		2331	Normally, you can just "forget" any references to an AnyEvent::Handle
		2332	object and it will simply shut down. This works in fatal error and EOF
		2333	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2334	callback, so when you want to destroy the AnyEvent::Handle object from
		2335	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2336	that case.
		2337
		2338	Destroying the handle object in this way has the advantage that callbacks
		2339	will be removed as well, so if those are the only reference holders (as
		2340	is common), then one doesn't need to do anything special to break any
		2341	reference cycles.
		2342
		2343	The handle might still linger in the background and write out remaining
		2344	data, as specified by the C<linger> option, however.
		2345
		2346	=cut
		2347
		2348	sub destroy {
		2349	my ($self) = @_;
		2350
		2351	$self->DESTROY;
		2352	%$self = ();
		2353	bless $self, "AnyEvent::Handle::destroyed";
		2354	}
		2355
		2356	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2357	#nop
		2358	}
		2359
		2360	=item $handle->destroyed
		2361
		2362	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2363	->destroy >>, true otherwise.
		2364
		2365	Can be useful to decide whether the handle is still valid after some
		2366	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2367	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2368	can destroy the handle, so work can be avoided by checking sometimes:
		2369
		2370	$hdl->starttls ("accept");
		2371	return if $hdl->destroyed;
		2372	$hdl->push_write (...
		2373
		2374	Note that the call to C<push_write> will silently be ignored if the handle
		2375	has been destroyed, so often you can just ignore the possibility of the
		2376	handle being destroyed.
		2377
		2378	=cut
		2379
		2380	sub destroyed { 0 }
		2381	sub AnyEvent::Handle::destroyed::destroyed { 1 }
		2382
		2383	=item AnyEvent::Handle::TLS_CTX
		2384
		2385	This function creates and returns the AnyEvent::TLS object used by default
		2386	for TLS mode.
		2387
		2388	The context is created by calling L<AnyEvent::TLS> without any arguments.
		2389
		2390	=cut
		2391
		2392	our $TLS_CTX;
		2393
		2394	sub TLS_CTX() {
		2395	$TLS_CTX ||= do {
		2396	require AnyEvent::TLS;
		2397
		2398	new AnyEvent::TLS
		2399	}
		2400	}
		2401
		2402	=back
		2403
		2404
		2405	=head1 NONFREQUENTLY ASKED QUESTIONS
		2406
		2407	=over 4
		2408
		2409	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2410	still get further invocations!
		2411
		2412	That's because AnyEvent::Handle keeps a reference to itself when handling
		2413	read or write callbacks.
		2414
		2415	It is only safe to "forget" the reference inside EOF or error callbacks,
		2416	from within all other callbacks, you need to explicitly call the C<<
		2417	->destroy >> method.
		2418
		2419	=item Why is my C<on_eof> callback never called?
		2420
		2421	Probably because your C<on_error> callback is being called instead: When
		2422	you have outstanding requests in your read queue, then an EOF is
		2423	considered an error as you clearly expected some data.
		2424
		2425	To avoid this, make sure you have an empty read queue whenever your handle
		2426	is supposed to be "idle" (i.e. connection closes are O.K.). You can set
		2427	an C<on_read> handler that simply pushes the first read requests in the
		2428	queue.
		2429
		2430	See also the next question, which explains this in a bit more detail.
		2431
		2432	=item How can I serve requests in a loop?
		2433
		2434	Most protocols consist of some setup phase (authentication for example)
		2435	followed by a request handling phase, where the server waits for requests
		2436	and handles them, in a loop.
		2437
		2438	There are two important variants: The first (traditional, better) variant
		2439	handles requests until the server gets some QUIT command, causing it to
		2440	close the connection first (highly desirable for a busy TCP server). A
		2441	client dropping the connection is an error, which means this variant can
		2442	detect an unexpected detection close.
		2443
		2444	To handle this case, always make sure you have a non-empty read queue, by
		2445	pushing the "read request start" handler on it:
		2446
		2447	# we assume a request starts with a single line
		2448	my @start_request; @start_request = (line => sub {
		2449	my ($hdl, $line) = @_;
		2450
		2451	... handle request
		2452
		2453	# push next request read, possibly from a nested callback
		2454	$hdl->push_read (@start_request);
		2455	});
		2456
		2457	# auth done, now go into request handling loop
		2458	# now push the first @start_request
		2459	$hdl->push_read (@start_request);
		2460
		2461	By always having an outstanding C<push_read>, the handle always expects
		2462	some data and raises the C<EPIPE> error when the connction is dropped
		2463	unexpectedly.
		2464
		2465	The second variant is a protocol where the client can drop the connection
		2466	at any time. For TCP, this means that the server machine may run out of
		2467	sockets easier, and in general, it means you cannot distinguish a protocl
		2468	failure/client crash from a normal connection close. Nevertheless, these
		2469	kinds of protocols are common (and sometimes even the best solution to the
		2470	problem).
		2471
		2472	Having an outstanding read request at all times is possible if you ignore
		2473	C<EPIPE> errors, but this doesn't help with when the client drops the
		2474	connection during a request, which would still be an error.
		2475
		2476	A better solution is to push the initial request read in an C<on_read>
		2477	callback. This avoids an error, as when the server doesn't expect data
		2478	(i.e. is idly waiting for the next request, an EOF will not raise an
		2479	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2480	and simpler:
		2481
		2482	# auth done, now go into request handling loop
		2483	$hdl->on_read (sub {
		2484	my ($hdl) = @_;
		2485
		2486	# called each time we receive data but the read queue is empty
		2487	# simply start read the request
		2488
		2489	$hdl->push_read (line => sub {
		2490	my ($hdl, $line) = @_;
		2491
		2492	... handle request
		2493
		2494	# do nothing special when the request has been handled, just
		2495	# let the request queue go empty.
363	});	2496	});
364	}	2497	});
		2498
		2499	=item I get different callback invocations in TLS mode/Why can't I pause
		2500	reading?
		2501
		2502	Unlike, say, TCP, TLS connections do not consist of two independent
		2503	communication channels, one for each direction. Or put differently, the
		2504	read and write directions are not independent of each other: you cannot
		2505	write data unless you are also prepared to read, and vice versa.
		2506
		2507	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2508	callback invocations when you are not expecting any read data - the reason
		2509	is that AnyEvent::Handle always reads in TLS mode.
		2510
		2511	During the connection, you have to make sure that you always have a
		2512	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2513	connection (or when you no longer want to use it) you can call the
		2514	C<destroy> method.
		2515
		2516	=item How do I read data until the other side closes the connection?
		2517
		2518	If you just want to read your data into a perl scalar, the easiest way
		2519	to achieve this is by setting an C<on_read> callback that does nothing,
		2520	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2521	will be in C<$_[0]{rbuf}>:
		2522
		2523	$handle->on_read (sub { });
		2524	$handle->on_eof (undef);
		2525	$handle->on_error (sub {
		2526	my $data = delete $_[0]{rbuf};
		2527	});
		2528
		2529	Note that this example removes the C<rbuf> member from the handle object,
		2530	which is not normally allowed by the API. It is expressly permitted in
		2531	this case only, as the handle object needs to be destroyed afterwards.
		2532
		2533	The reason to use C<on_error> is that TCP connections, due to latencies
		2534	and packets loss, might get closed quite violently with an error, when in
		2535	fact all data has been received.
		2536
		2537	It is usually better to use acknowledgements when transferring data,
		2538	to make sure the other side hasn't just died and you got the data
		2539	intact. This is also one reason why so many internet protocols have an
		2540	explicit QUIT command.
		2541
		2542	=item I don't want to destroy the handle too early - how do I wait until
		2543	all data has been written?
		2544
		2545	After writing your last bits of data, set the C<on_drain> callback
		2546	and destroy the handle in there - with the default setting of
		2547	C<low_water_mark> this will be called precisely when all data has been
		2548	written to the socket:
		2549
		2550	$handle->push_write (...);
		2551	$handle->on_drain (sub {
		2552	AE::log debug => "All data submitted to the kernel.";
		2553	undef $handle;
		2554	});
		2555
		2556	If you just want to queue some data and then signal EOF to the other side,
		2557	consider using C<< ->push_shutdown >> instead.
		2558
		2559	=item I want to contact a TLS/SSL server, I don't care about security.
		2560
		2561	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2562	connect to it and then create the AnyEvent::Handle with the C<tls>
		2563	parameter:
		2564
		2565	tcp_connect $host, $port, sub {
		2566	my ($fh) = @_;
		2567
		2568	my $handle = new AnyEvent::Handle
		2569	fh => $fh,
		2570	tls => "connect",
		2571	on_error => sub { ... };
		2572
		2573	$handle->push_write (...);
		2574	};
		2575
		2576	=item I want to contact a TLS/SSL server, I do care about security.
		2577
		2578	Then you should additionally enable certificate verification, including
		2579	peername verification, if the protocol you use supports it (see
		2580	L<AnyEvent::TLS>, C<verify_peername>).
		2581
		2582	E.g. for HTTPS:
		2583
		2584	tcp_connect $host, $port, sub {
		2585	my ($fh) = @_;
		2586
		2587	my $handle = new AnyEvent::Handle
		2588	fh => $fh,
		2589	peername => $host,
		2590	tls => "connect",
		2591	tls_ctx => { verify => 1, verify_peername => "https" },
		2592	...
		2593
		2594	Note that you must specify the hostname you connected to (or whatever
		2595	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2596	peername verification will be done.
		2597
		2598	The above will use the system-dependent default set of trusted CA
		2599	certificates. If you want to check against a specific CA, add the
		2600	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2601
		2602	tls_ctx => {
		2603	verify => 1,
		2604	verify_peername => "https",
		2605	ca_file => "my-ca-cert.pem",
		2606	},
		2607
		2608	=item I want to create a TLS/SSL server, how do I do that?
		2609
		2610	Well, you first need to get a server certificate and key. You have
		2611	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2612	self-signed certificate (cheap. check the search engine of your choice,
		2613	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2614	nice program for that purpose).
		2615
		2616	Then create a file with your private key (in PEM format, see
		2617	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2618	file should then look like this:
		2619
		2620	-----BEGIN RSA PRIVATE KEY-----
		2621	...header data
		2622	... lots of base64'y-stuff
		2623	-----END RSA PRIVATE KEY-----
		2624
		2625	-----BEGIN CERTIFICATE-----
		2626	... lots of base64'y-stuff
		2627	-----END CERTIFICATE-----
		2628
		2629	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2630	specify this file as C<cert_file>:
		2631
		2632	tcp_server undef, $port, sub {
		2633	my ($fh) = @_;
		2634
		2635	my $handle = new AnyEvent::Handle
		2636	fh => $fh,
		2637	tls => "accept",
		2638	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2639	...
		2640
		2641	When you have intermediate CA certificates that your clients might not
		2642	know about, just append them to the C<cert_file>.
365		2643
366	=back	2644	=back
367		2645
		2646	=head1 SUBCLASSING AnyEvent::Handle
		2647
		2648	In many cases, you might want to subclass AnyEvent::Handle.
		2649
		2650	To make this easier, a given version of AnyEvent::Handle uses these
		2651	conventions:
		2652
		2653	=over 4
		2654
		2655	=item * all constructor arguments become object members.
		2656
		2657	At least initially, when you pass a C<tls>-argument to the constructor it
		2658	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2659	mutated later on (for example C<tls> will hold the TLS connection object).
		2660
		2661	=item * other object member names are prefixed with an C<_>.
		2662
		2663	All object members not explicitly documented (internal use) are prefixed
		2664	with an underscore character, so the remaining non-C<_>-namespace is free
		2665	for use for subclasses.
		2666
		2667	=item * all members not documented here and not prefixed with an underscore
		2668	are free to use in subclasses.
		2669
		2670	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2671	member variables, but that's just life. At least it is documented.
		2672
		2673	=back
		2674
368	=head1 AUTHOR	2675	=head1 AUTHOR
369		2676
370	Robin Redeker, C<< <elmex at ta-sa.org> >>	2677	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
371		2678
372	=cut	2679	=cut
373		2680
374	1; # End of AnyEvent::Handle	2681	1
		2682

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