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Revision 1.6 by elmex, Mon Apr 28 09:27:47 2008 UTC vs.
Revision 1.250 by root, Tue Feb 26 01:35:48 2019 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	$self->_drain_wbuf;
		646	}
		647
		648	sub _error {
		649	my ($self, $errno, $fatal, $message) = @_;
		650
		651	$! = $errno;
		652	$message ||= "$!";
		653
		654	if ($self->{on_error}) {
		655	$self->{on_error}($self, $fatal, $message);
		656	$self->destroy if $fatal;
		657	} elsif ($self->{fh} || $self->{connect}) {
		658	$self->destroy;
		659	Carp::croak "AnyEvent::Handle uncaught error: $message";
		660	}
		661	}
		662
		663	=item $fh = $handle->fh
		664
		665	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		666
		667	=cut
		668
		669	sub fh { $_[0]{fh} }
		670
		671	=item $handle->on_error ($cb)
		672
		673	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		674
		675	=cut
		676
		677	sub on_error {
		678	$_[0]{on_error} = $_[1];
		679	}
		680
		681	=item $handle->on_eof ($cb)
		682
		683	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		684
		685	=cut
		686
		687	sub on_eof {
		688	$_[0]{on_eof} = $_[1];
		689	}
		690
		691	=item $handle->on_timeout ($cb)
		692
		693	=item $handle->on_rtimeout ($cb)
		694
		695	=item $handle->on_wtimeout ($cb)
		696
		697	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		698	callback, or disables the callback (but not the timeout) if C<$cb> =
		699	C<undef>. See the C<timeout> constructor argument and method.
		700
		701	=cut
		702
		703	# see below
		704
		705	=item $handle->autocork ($boolean)
		706
		707	Enables or disables the current autocork behaviour (see C<autocork>
		708	constructor argument). Changes will only take effect on the next write.
		709
		710	=cut
		711
		712	sub autocork {
		713	$_[0]{autocork} = $_[1];
		714	}
		715
		716	=item $handle->no_delay ($boolean)
		717
		718	Enables or disables the C<no_delay> setting (see constructor argument of
		719	the same name for details).
		720
		721	=cut
		722
		723	sub no_delay {
		724	$_[0]{no_delay} = $_[1];
		725
		726	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		727	if $_[0]{fh};
		728	}
		729
		730	=item $handle->keepalive ($boolean)
		731
		732	Enables or disables the C<keepalive> setting (see constructor argument of
		733	the same name for details).
		734
		735	=cut
		736
		737	sub keepalive {
		738	$_[0]{keepalive} = $_[1];
		739
		740	eval {
		741	local $SIG{__DIE__};
		742	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		743	if $_[0]{fh};
		744	};
		745	}
		746
		747	=item $handle->oobinline ($boolean)
		748
		749	Enables or disables the C<oobinline> setting (see constructor argument of
		750	the same name for details).
		751
		752	=cut
		753
		754	sub oobinline {
		755	$_[0]{oobinline} = $_[1];
		756
		757	eval {
		758	local $SIG{__DIE__};
		759	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		760	if $_[0]{fh};
		761	};
		762	}
		763
		764	=item $handle->on_starttls ($cb)
		765
		766	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		767
		768	=cut
		769
		770	sub on_starttls {
		771	$_[0]{on_starttls} = $_[1];
		772	}
		773
		774	=item $handle->on_stoptls ($cb)
		775
		776	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		777
		778	=cut
		779
		780	sub on_stoptls {
		781	$_[0]{on_stoptls} = $_[1];
		782	}
		783
		784	=item $handle->rbuf_max ($max_octets)
		785
		786	Configures the C<rbuf_max> setting (C<undef> disables it).
		787
		788	=item $handle->wbuf_max ($max_octets)
		789
		790	Configures the C<wbuf_max> setting (C<undef> disables it).
		791
		792	=cut
		793
		794	sub rbuf_max {
		795	$_[0]{rbuf_max} = $_[1];
		796	}
		797
		798	sub wbuf_max {
		799	$_[0]{wbuf_max} = $_[1];
		800	}
		801
		802	#############################################################################
		803
		804	=item $handle->timeout ($seconds)
		805
		806	=item $handle->rtimeout ($seconds)
		807
		808	=item $handle->wtimeout ($seconds)
		809
		810	Configures (or disables) the inactivity timeout.
		811
		812	The timeout will be checked instantly, so this method might destroy the
		813	handle before it returns.
		814
		815	=item $handle->timeout_reset
		816
		817	=item $handle->rtimeout_reset
		818
		819	=item $handle->wtimeout_reset
		820
		821	Reset the activity timeout, as if data was received or sent.
		822
		823	These methods are cheap to call.
		824
		825	=cut
		826
		827	for my $dir ("", "r", "w") {
		828	my $timeout = "${dir}timeout";
		829	my $tw = "_${dir}tw";
		830	my $on_timeout = "on_${dir}timeout";
		831	my $activity = "_${dir}activity";
		832	my $cb;
		833
		834	*$on_timeout = sub {
		835	$_[0]{$on_timeout} = $_[1];
		836	};
		837
		838	*$timeout = sub {
		839	my ($self, $new_value) = @_;
		840
		841	$new_value >= 0
		842	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		843
		844	$self->{$timeout} = $new_value;
		845	delete $self->{$tw}; &$cb;
		846	};
		847
		848	*{"${dir}timeout_reset"} = sub {
		849	$_[0]{$activity} = AE::now;
		850	};
		851
		852	# main workhorse:
		853	# reset the timeout watcher, as neccessary
		854	# also check for time-outs
		855	$cb = sub {
		856	my ($self) = @_;
		857
		858	if ($self->{$timeout} && $self->{fh}) {
		859	my $NOW = AE::now;
		860
		861	# when would the timeout trigger?
		862	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		863
		864	# now or in the past already?
		865	if ($after <= 0) {
		866	$self->{$activity} = $NOW;
		867
		868	if ($self->{$on_timeout}) {
		869	$self->{$on_timeout}($self);
		870	} else {
		871	$self->_error (Errno::ETIMEDOUT);
		872	}
		873
		874	# callback could have changed timeout value, optimise
		875	return unless $self->{$timeout};
		876
		877	# calculate new after
		878	$after = $self->{$timeout};
		879	}
		880
		881	Scalar::Util::weaken $self;
		882	return unless $self; # ->error could have destroyed $self
		883
		884	$self->{$tw} ||= AE::timer $after, 0, sub {
		885	delete $self->{$tw};
		886	$cb->($self);
36	chomp;	887	};
37	print "Line: $_";	888	} else {
		889	delete $self->{$tw};
		890	}
		891	}
		892	}
		893
		894	#############################################################################
		895
		896	=back
		897
		898	=head2 WRITE QUEUE
		899
		900	AnyEvent::Handle manages two queues per handle, one for writing and one
		901	for reading.
		902
		903	The write queue is very simple: you can add data to its end, and
		904	AnyEvent::Handle will automatically try to get rid of it for you.
		905
		906	When data could be written and the write buffer is shorter then the low
		907	water mark, the C<on_drain> callback will be invoked once.
		908
		909	=over 4
		910
		911	=item $handle->on_drain ($cb)
		912
		913	Sets the C<on_drain> callback or clears it (see the description of
		914	C<on_drain> in the constructor).
		915
		916	This method may invoke callbacks (and therefore the handle might be
		917	destroyed after it returns).
		918
		919	=cut
		920
		921	sub on_drain {
		922	my ($self, $cb) = @_;
		923
		924	$self->{on_drain} = $cb;
		925
		926	$cb->($self)
		927	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		928	}
		929
		930	=item $handle->push_write ($data)
		931
		932	Queues the given scalar to be written. You can push as much data as
		933	you want (only limited by the available memory and C<wbuf_max>), as
		934	C<AnyEvent::Handle> buffers it independently of the kernel.
		935
		936	This method may invoke callbacks (and therefore the handle might be
		937	destroyed after it returns).
		938
		939	=cut
		940
		941	sub _drain_wbuf {
		942	my ($self) = @_;
		943
		944	if (!$self->{_ww} && length $self->{wbuf}) {
		945
		946	Scalar::Util::weaken $self;
		947
		948	my $cb = sub {
		949	my $len = syswrite $self->{fh}, $self->{wbuf};
		950
		951	if (defined $len) {
		952	substr $self->{wbuf}, 0, $len, "";
		953
		954	$self->{_activity} = $self->{_wactivity} = AE::now;
		955
		956	$self->{on_drain}($self)
		957	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		958	&& $self->{on_drain};
		959
		960	delete $self->{_ww} unless length $self->{wbuf};
		961	} elsif ($! != EAGAIN && $! != EINTR && $! != EWOULDBLOCK && $! != WSAEWOULDBLOCK) {
		962	$self->_error ($!, 1);
		963	}
		964	};
		965
		966	# try to write data immediately
		967	$cb->() unless $self->{autocork};
		968
		969	# if still data left in wbuf, we need to poll
		970	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		971	if length $self->{wbuf};
		972
		973	if (
		974	defined $self->{wbuf_max}
		975	&& $self->{wbuf_max} < length $self->{wbuf}
		976	) {
		977	$self->_error (Errno::ENOSPC, 1), return;
		978	}
		979	};
		980	}
		981
		982	our %WH;
		983
		984	# deprecated
		985	sub register_write_type($$) {
		986	$WH{$_[0]} = $_[1];
		987	}
		988
		989	sub push_write {
		990	my $self = shift;
		991
		992	if (@_ > 1) {
		993	my $type = shift;
		994
		995	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
		996	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
		997	->($self, @_);
		998	}
		999
		1000	# we downgrade here to avoid hard-to-track-down bugs,
		1001	# and diagnose the problem earlier and better.
		1002
		1003	if ($self->{tls}) {
		1004	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		1005	&_dotls ($self) if $self->{fh};
		1006	} else {
		1007	utf8::downgrade $self->{wbuf} .= $_[0];
		1008	$self->_drain_wbuf if $self->{fh};
		1009	}
		1010	}
		1011
		1012	=item $handle->push_write (type => @args)
		1013
		1014	Instead of formatting your data yourself, you can also let this module
		1015	do the job by specifying a type and type-specific arguments. You
		1016	can also specify the (fully qualified) name of a package, in which
		1017	case AnyEvent tries to load the package and then expects to find the
		1018	C<anyevent_write_type> function inside (see "custom write types", below).
		1019
		1020	Predefined types are (if you have ideas for additional types, feel free to
		1021	drop by and tell us):
		1022
		1023	=over 4
		1024
		1025	=item netstring => $string
		1026
		1027	Formats the given value as netstring
		1028	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		1029
		1030	=cut
		1031
		1032	register_write_type netstring => sub {
		1033	my ($self, $string) = @_;
		1034
		1035	(length $string) . ":$string,"
		1036	};
		1037
		1038	=item packstring => $format, $data
		1039
		1040	An octet string prefixed with an encoded length. The encoding C<$format>
		1041	uses the same format as a Perl C<pack> format, but must specify a single
		1042	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1043	optional C<!>, C<< < >> or C<< > >> modifier).
		1044
		1045	=cut
		1046
		1047	register_write_type packstring => sub {
		1048	my ($self, $format, $string) = @_;
		1049
		1050	pack "$format/a*", $string
		1051	};
		1052
		1053	=item json => $array_or_hashref
		1054
		1055	Encodes the given hash or array reference into a JSON object. Unless you
		1056	provide your own JSON object, this means it will be encoded to JSON text
		1057	in UTF-8.
		1058
		1059	The default encoder might or might not handle every type of JSON value -
		1060	it might be limited to arrays and objects for security reasons. See the
		1061	C<json> constructor attribute for more details.
		1062
		1063	JSON objects (and arrays) are self-delimiting, so if you only use arrays
		1064	and hashes, you can write JSON at one end of a handle and read them at the
		1065	other end without using any additional framing.
		1066
		1067	The JSON text generated by the default encoder is guaranteed not to
		1068	contain any newlines: While this module doesn't need delimiters after or
		1069	between JSON texts to be able to read them, many other languages depend on
		1070	them.
		1071
		1072	A simple RPC protocol that interoperates easily with other languages is
		1073	to send JSON arrays (or objects, although arrays are usually the better
		1074	choice as they mimic how function argument passing works) and a newline
		1075	after each JSON text:
		1076
		1077	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		1078	$handle->push_write ("\012");
		1079
		1080	An AnyEvent::Handle receiver would simply use the C<json> read type and
		1081	rely on the fact that the newline will be skipped as leading whitespace:
		1082
		1083	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1084
		1085	Other languages could read single lines terminated by a newline and pass
		1086	this line into their JSON decoder of choice.
		1087
		1088	=item cbor => $perl_scalar
		1089
		1090	Encodes the given scalar into a CBOR value. Unless you provide your own
		1091	L<CBOR::XS> object, this means it will be encoded to a CBOR string not
		1092	using any extensions, if possible.
		1093
		1094	CBOR values are self-delimiting, so you can write CBOR at one end of
		1095	a handle and read them at the other end without using any additional
		1096	framing.
		1097
		1098	A simple nd very very fast RPC protocol that interoperates with
		1099	other languages is to send CBOR and receive CBOR values (arrays are
		1100	recommended):
		1101
		1102	$handle->push_write (cbor => ["method", "arg1", "arg2"]); # whatever
		1103
		1104	An AnyEvent::Handle receiver would simply use the C<cbor> read type:
		1105
		1106	$handle->push_read (cbor => sub { my $array = $_[1]; ... });
		1107
		1108	=cut
		1109
		1110	sub json_coder() {
		1111	eval { require JSON::XS; JSON::XS->new->utf8 }
		1112	|| do { require JSON::PP; JSON::PP->new->utf8 }
		1113	}
		1114
		1115	register_write_type json => sub {
		1116	my ($self, $ref) = @_;
		1117
		1118	($self->{json} ||= json_coder)
		1119	->encode ($ref)
		1120	};
		1121
		1122	sub cbor_coder() {
		1123	require CBOR::XS;
		1124	CBOR::XS->new
		1125	}
		1126
		1127	register_write_type cbor => sub {
		1128	my ($self, $scalar) = @_;
		1129
		1130	($self->{cbor} ||= cbor_coder)
		1131	->encode ($scalar)
		1132	};
		1133
		1134	=item storable => $reference
		1135
		1136	Freezes the given reference using L<Storable> and writes it to the
		1137	handle. Uses the C<nfreeze> format.
		1138
		1139	=cut
		1140
		1141	register_write_type storable => sub {
		1142	my ($self, $ref) = @_;
		1143
		1144	require Storable unless $Storable::VERSION;
		1145
		1146	pack "w/a*", Storable::nfreeze ($ref)
		1147	};
		1148
		1149	=back
		1150
		1151	=item $handle->push_shutdown
		1152
		1153	Sometimes you know you want to close the socket after writing your data
		1154	before it was actually written. One way to do that is to replace your
		1155	C<on_drain> handler by a callback that shuts down the socket (and set
		1156	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1157	replaces the C<on_drain> callback with:
		1158
		1159	sub { shutdown $_[0]{fh}, 1 }
		1160
		1161	This simply shuts down the write side and signals an EOF condition to the
		1162	the peer.
		1163
		1164	You can rely on the normal read queue and C<on_eof> handling
		1165	afterwards. This is the cleanest way to close a connection.
		1166
		1167	This method may invoke callbacks (and therefore the handle might be
		1168	destroyed after it returns).
		1169
		1170	=cut
		1171
		1172	sub push_shutdown {
		1173	my ($self) = @_;
		1174
		1175	delete $self->{low_water_mark};
		1176	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1177	}
		1178
		1179	=item custom write types - Package::anyevent_write_type $handle, @args
		1180
		1181	Instead of one of the predefined types, you can also specify the name of
		1182	a package. AnyEvent will try to load the package and then expects to find
		1183	a function named C<anyevent_write_type> inside. If it isn't found, it
		1184	progressively tries to load the parent package until it either finds the
		1185	function (good) or runs out of packages (bad).
		1186
		1187	Whenever the given C<type> is used, C<push_write> will the function with
		1188	the handle object and the remaining arguments.
		1189
		1190	The function is supposed to return a single octet string that will be
		1191	appended to the write buffer, so you can mentally treat this function as a
		1192	"arguments to on-the-wire-format" converter.
		1193
		1194	Example: implement a custom write type C<join> that joins the remaining
		1195	arguments using the first one.
		1196
		1197	$handle->push_write (My::Type => " ", 1,2,3);
		1198
		1199	# uses the following package, which can be defined in the "My::Type" or in
		1200	# the "My" modules to be auto-loaded, or just about anywhere when the
		1201	# My::Type::anyevent_write_type is defined before invoking it.
		1202
		1203	package My::Type;
		1204
		1205	sub anyevent_write_type {
		1206	my ($handle, $delim, @args) = @_;
		1207
		1208	join $delim, @args
		1209	}
		1210
		1211	=cut
		1212
		1213	#############################################################################
		1214
		1215	=back
		1216
		1217	=head2 READ QUEUE
		1218
		1219	AnyEvent::Handle manages two queues per handle, one for writing and one
		1220	for reading.
		1221
		1222	The read queue is more complex than the write queue. It can be used in two
		1223	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		1224	a queue.
		1225
		1226	In the simple case, you just install an C<on_read> callback and whenever
		1227	new data arrives, it will be called. You can then remove some data (if
		1228	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
		1229	leave the data there if you want to accumulate more (e.g. when only a
		1230	partial message has been received so far), or change the read queue with
		1231	e.g. C<push_read>.
		1232
		1233	In the more complex case, you want to queue multiple callbacks. In this
		1234	case, AnyEvent::Handle will call the first queued callback each time new
		1235	data arrives (also the first time it is queued) and remove it when it has
		1236	done its job (see C<push_read>, below).
		1237
		1238	This way you can, for example, push three line-reads, followed by reading
		1239	a chunk of data, and AnyEvent::Handle will execute them in order.
		1240
		1241	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		1242	the specified number of bytes which give an XML datagram.
		1243
		1244	# in the default state, expect some header bytes
		1245	$handle->on_read (sub {
		1246	# some data is here, now queue the length-header-read (4 octets)
		1247	shift->unshift_read (chunk => 4, sub {
		1248	# header arrived, decode
		1249	my $len = unpack "N", $_[1];
		1250
		1251	# now read the payload
		1252	shift->unshift_read (chunk => $len, sub {
		1253	my $xml = $_[1];
		1254	# handle xml
		1255	});
		1256	});
		1257	});
		1258
		1259	Example 2: Implement a client for a protocol that replies either with "OK"
		1260	and another line or "ERROR" for the first request that is sent, and 64
		1261	bytes for the second request. Due to the availability of a queue, we can
		1262	just pipeline sending both requests and manipulate the queue as necessary
		1263	in the callbacks.
		1264
		1265	When the first callback is called and sees an "OK" response, it will
		1266	C<unshift> another line-read. This line-read will be queued I<before> the
		1267	64-byte chunk callback.
		1268
		1269	# request one, returns either "OK + extra line" or "ERROR"
		1270	$handle->push_write ("request 1\015\012");
		1271
		1272	# we expect "ERROR" or "OK" as response, so push a line read
		1273	$handle->push_read (line => sub {
		1274	# if we got an "OK", we have to _prepend_ another line,
		1275	# so it will be read before the second request reads its 64 bytes
		1276	# which are already in the queue when this callback is called
		1277	# we don't do this in case we got an error
		1278	if ($_[1] eq "OK") {
		1279	$_[0]->unshift_read (line => sub {
		1280	my $response = $_[1];
		1281	...
		1282	});
38	}	1283	}
39	});	1284	});
40		1285
41	# or use the constructor to pass the callback:	1286	# request two, simply returns 64 octets
		1287	$handle->push_write ("request 2\015\012");
42		1288
43	my $ae_fh2 =	1289	# simply read 64 bytes, always
44	AnyEvent::Handle->new (	1290	$handle->push_read (chunk => 64, sub {
45	fh => \*STDIN,	1291	my $response = $_[1];
46	on_eof => sub {	1292	...
47	$cv->broadcast;	1293	});
48	},	1294
49	on_readline => sub {	1295	=over 4
50	my ($ae_fh, @lines) = @_;	1296
51	for (@lines) {	1297	=cut
52	chomp;	1298
53	print "Line: $_";	1299	sub _drain_rbuf {
		1300	my ($self) = @_;
		1301
		1302	# avoid recursion
		1303	return if $self->{_skip_drain_rbuf};
		1304	local $self->{_skip_drain_rbuf} = 1;
		1305
		1306	while () {
		1307	# we need to use a separate tls read buffer, as we must not receive data while
		1308	# we are draining the buffer, and this can only happen with TLS.
		1309	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1310	if exists $self->{_tls_rbuf};
		1311
		1312	my $len = length $self->{rbuf};
		1313
		1314	if (my $cb = shift @{ $self->{_queue} }) {
		1315	unless ($cb->($self)) {
		1316	# no progress can be made
		1317	# (not enough data and no data forthcoming)
		1318	$self->_error (Errno::EPIPE, 1), return
		1319	if $self->{_eof};
		1320
		1321	unshift @{ $self->{_queue} }, $cb;
54	}	1322	last;
55	}	1323	}
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}) {	1324	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	1325	last unless $len;
122		1326
		1327	$self->{on_read}($self);
		1328
		1329	if (
		1330	$len == length $self->{rbuf} # if no data has been consumed
		1331	&& !@{ $self->{_queue} } # and the queue is still empty
		1332	&& $self->{on_read} # but we still have on_read
		1333	) {
		1334	# no further data will arrive
		1335	# so no progress can be made
		1336	$self->_error (Errno::EPIPE, 1), return
		1337	if $self->{_eof};
		1338
		1339	last; # more data might arrive
		1340	}
		1341	} else {
		1342	# read side becomes idle
		1343	delete $self->{_rw} unless $self->{tls};
		1344	last;
		1345	}
		1346	}
		1347
123	} elsif ($self->{on_eof}) {	1348	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});	1349	$self->{on_eof}
		1350	? $self->{on_eof}($self)
		1351	: $self->_error (0, 1, "Unexpected end-of-file");
125		1352
126	} elsif ($self->{on_error}) {	1353	return;
127	$self->on_eof ($self->{on_error});
128	}	1354	}
129		1355
130	return $self	1356	if (
131	}	1357	defined $self->{rbuf_max}
		1358	&& $self->{rbuf_max} < length $self->{rbuf}
		1359	) {
		1360	$self->_error (Errno::ENOSPC, 1), return;
		1361	}
132		1362
133	=item B<fh>	1363	# may need to restart read watcher
		1364	unless ($self->{_rw}) {
		1365	$self->start_read
		1366	if $self->{on_read} || @{ $self->{_queue} };
		1367	}
		1368	}
134		1369
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	1370	=item $handle->on_read ($cb)
136		1371
137	=cut	1372	This replaces the currently set C<on_read> callback, or clears it (when
		1373	the new callback is C<undef>). See the description of C<on_read> in the
		1374	constructor.
138		1375
139	sub fh { $_[0]->{fh} }	1376	This method may invoke callbacks (and therefore the handle might be
140		1377	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		1378
149	=cut	1379	=cut
150		1380
151	sub on_read {	1381	sub on_read {
152	my ($self, $cb) = @_;	1382	my ($self, $cb) = @_;
		1383
153	$self->{on_read} = $cb;	1384	$self->{on_read} = $cb;
		1385	$self->_drain_rbuf if $cb;
		1386	}
154		1387
155	unless (defined $self->{on_read}) {	1388	=item $handle->rbuf
156	delete $self->{on_read_w};	1389
		1390	Returns the read buffer (as a modifiable lvalue). You can also access the
		1391	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1392	much faster, and no less clean).
		1393
		1394	The only operation allowed on the read buffer (apart from looking at it)
		1395	is removing data from its beginning. Otherwise modifying or appending to
		1396	it is not allowed and will lead to hard-to-track-down bugs.
		1397
		1398	NOTE: The read buffer should only be used or modified in the C<on_read>
		1399	callback or when C<push_read> or C<unshift_read> are used with a single
		1400	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1401	will manage the read buffer on their own.
		1402
		1403	=cut
		1404
		1405	sub rbuf : lvalue {
		1406	$_[0]{rbuf}
		1407	}
		1408
		1409	=item $handle->push_read ($cb)
		1410
		1411	=item $handle->unshift_read ($cb)
		1412
		1413	Append the given callback to the end of the queue (C<push_read>) or
		1414	prepend it (C<unshift_read>).
		1415
		1416	The callback is called each time some additional read data arrives.
		1417
		1418	It must check whether enough data is in the read buffer already.
		1419
		1420	If not enough data is available, it must return the empty list or a false
		1421	value, in which case it will be called repeatedly until enough data is
		1422	available (or an error condition is detected).
		1423
		1424	If enough data was available, then the callback must remove all data it is
		1425	interested in (which can be none at all) and return a true value. After returning
		1426	true, it will be removed from the queue.
		1427
		1428	These methods may invoke callbacks (and therefore the handle might be
		1429	destroyed after it returns).
		1430
		1431	=cut
		1432
		1433	our %RH;
		1434
		1435	sub register_read_type($$) {
		1436	$RH{$_[0]} = $_[1];
		1437	}
		1438
		1439	sub push_read {
		1440	my $self = shift;
		1441	my $cb = pop;
		1442
		1443	if (@_) {
		1444	my $type = shift;
		1445
		1446	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1447	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
		1448	->($self, $cb, @_);
		1449	}
		1450
		1451	push @{ $self->{_queue} }, $cb;
		1452	$self->_drain_rbuf;
		1453	}
		1454
		1455	sub unshift_read {
		1456	my $self = shift;
		1457	my $cb = pop;
		1458
		1459	if (@_) {
		1460	my $type = shift;
		1461
		1462	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
		1463	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
		1464	->($self, $cb, @_);
		1465	}
		1466
		1467	unshift @{ $self->{_queue} }, $cb;
		1468	$self->_drain_rbuf;
		1469	}
		1470
		1471	=item $handle->push_read (type => @args, $cb)
		1472
		1473	=item $handle->unshift_read (type => @args, $cb)
		1474
		1475	Instead of providing a callback that parses the data itself you can chose
		1476	between a number of predefined parsing formats, for chunks of data, lines
		1477	etc. You can also specify the (fully qualified) name of a package, in
		1478	which case AnyEvent tries to load the package and then expects to find the
		1479	C<anyevent_read_type> function inside (see "custom read types", below).
		1480
		1481	Predefined types are (if you have ideas for additional types, feel free to
		1482	drop by and tell us):
		1483
		1484	=over 4
		1485
		1486	=item chunk => $octets, $cb->($handle, $data)
		1487
		1488	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1489	data read to the callback. The callback will never be called with less
		1490	data.
		1491
		1492	Example: read 2 bytes.
		1493
		1494	$handle->push_read (chunk => 2, sub {
		1495	say "yay " . unpack "H*", $_[1];
		1496	});
		1497
		1498	=cut
		1499
		1500	register_read_type chunk => sub {
		1501	my ($self, $cb, $len) = @_;
		1502
		1503	sub {
		1504	$len <= length $_[0]{rbuf} or return;
		1505	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		1506	1
		1507	}
		1508	};
		1509
		1510	=item line => [$eol, ]$cb->($handle, $line, $eol)
		1511
		1512	The callback will be called only once a full line (including the end of
		1513	line marker, C<$eol>) has been read. This line (excluding the end of line
		1514	marker) will be passed to the callback as second argument (C<$line>), and
		1515	the end of line marker as the third argument (C<$eol>).
		1516
		1517	The end of line marker, C<$eol>, can be either a string, in which case it
		1518	will be interpreted as a fixed record end marker, or it can be a regex
		1519	object (e.g. created by C<qr>), in which case it is interpreted as a
		1520	regular expression.
		1521
		1522	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		1523	undef), then C<qr|\015?\012|> is used (which is good for most internet
		1524	protocols).
		1525
		1526	Partial lines at the end of the stream will never be returned, as they are
		1527	not marked by the end of line marker.
		1528
		1529	=cut
		1530
		1531	register_read_type line => sub {
		1532	my ($self, $cb, $eol) = @_;
		1533
		1534	if (@_ < 3) {
		1535	# this is faster then the generic code below
		1536	sub {
		1537	(my $pos = index $_[0]{rbuf}, "\012") >= 0
		1538	or return;
		1539
		1540	(my $str = substr $_[0]{rbuf}, 0, $pos + 1, "") =~ s/(\015?\012)\Z// or die;
		1541	$cb->($_[0], $str, "$1");
		1542	1
		1543	}
		1544	} else {
		1545	$eol = quotemeta $eol unless ref $eol;
		1546	$eol = qr|^(.*?)($eol)|s;
		1547
		1548	sub {
		1549	$_[0]{rbuf} =~ s/$eol// or return;
		1550
		1551	$cb->($_[0], "$1", "$2");
		1552	1
		1553	}
		1554	}
		1555	};
		1556
		1557	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1558
		1559	Makes a regex match against the regex object C<$accept> and returns
		1560	everything up to and including the match. All the usual regex variables
		1561	($1, %+ etc.) from the regex match are available in the callback.
		1562
		1563	Example: read a single line terminated by '\n'.
		1564
		1565	$handle->push_read (regex => qr<\n>, sub { ... });
		1566
		1567	If C<$reject> is given and not undef, then it determines when the data is
		1568	to be rejected: it is matched against the data when the C<$accept> regex
		1569	does not match and generates an C<EBADMSG> error when it matches. This is
		1570	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1571	receive buffer overflow).
		1572
		1573	Example: expect a single decimal number followed by whitespace, reject
		1574	anything else (not the use of an anchor).
		1575
		1576	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1577
		1578	If C<$skip> is given and not C<undef>, then it will be matched against
		1579	the receive buffer when neither C<$accept> nor C<$reject> match,
		1580	and everything preceding and including the match will be accepted
		1581	unconditionally. This is useful to skip large amounts of data that you
		1582	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1583	have to start matching from the beginning. This is purely an optimisation
		1584	and is usually worth it only when you expect more than a few kilobytes.
		1585
		1586	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1587	expect the header to be very large (it isn't in practice, but...), we use
		1588	a skip regex to skip initial portions. The skip regex is tricky in that
		1589	it only accepts something not ending in either \015 or \012, as these are
		1590	required for the accept regex.
		1591
		1592	$handle->push_read (regex =>
		1593	qr<\015\012\015\012>,
		1594	undef, # no reject
		1595	qr<^.*[^\015\012]>,
		1596	sub { ... });
		1597
		1598	=cut
		1599
		1600	register_read_type regex => sub {
		1601	my ($self, $cb, $accept, $reject, $skip) = @_;
		1602
		1603	my $data;
		1604	my $rbuf = \$self->{rbuf};
		1605
		1606	sub {
		1607	# accept
		1608	if ($$rbuf =~ $accept) {
		1609	$data .= substr $$rbuf, 0, $+[0], "";
		1610	$cb->($_[0], $data);
		1611	return 1;
		1612	}
		1613
		1614	# reject
		1615	if ($reject && $$rbuf =~ $reject) {
		1616	$_[0]->_error (Errno::EBADMSG);
		1617	}
		1618
		1619	# skip
		1620	if ($skip && $$rbuf =~ $skip) {
		1621	$data .= substr $$rbuf, 0, $+[0], "";
		1622	}
		1623
		1624	()
		1625	}
		1626	};
		1627
		1628	=item netstring => $cb->($handle, $string)
		1629
		1630	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1631
		1632	Throws an error with C<$!> set to EBADMSG on format violations.
		1633
		1634	=cut
		1635
		1636	register_read_type netstring => sub {
		1637	my ($self, $cb) = @_;
		1638
		1639	sub {
		1640	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1641	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1642	$_[0]->_error (Errno::EBADMSG);
		1643	}
157	return;	1644	return;
		1645	}
		1646
		1647	my $len = $1;
		1648
		1649	$_[0]->unshift_read (chunk => $len, sub {
		1650	my $string = $_[1];
		1651	$_[0]->unshift_read (chunk => 1, sub {
		1652	if ($_[1] eq ",") {
		1653	$cb->($_[0], $string);
		1654	} else {
		1655	$_[0]->_error (Errno::EBADMSG);
		1656	}
		1657	});
		1658	});
		1659
		1660	1
		1661	}
		1662	};
		1663
		1664	=item packstring => $format, $cb->($handle, $string)
		1665
		1666	An octet string prefixed with an encoded length. The encoding C<$format>
		1667	uses the same format as a Perl C<pack> format, but must specify a single
		1668	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1669	optional C<!>, C<< < >> or C<< > >> modifier).
		1670
		1671	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1672	EPP uses a prefix of C<N> (4 octtes).
		1673
		1674	Example: read a block of data prefixed by its length in BER-encoded
		1675	format (very efficient).
		1676
		1677	$handle->push_read (packstring => "w", sub {
		1678	my ($handle, $data) = @_;
		1679	});
		1680
		1681	=cut
		1682
		1683	register_read_type packstring => sub {
		1684	my ($self, $cb, $format) = @_;
		1685
		1686	sub {
		1687	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1688	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1689	or return;
		1690
		1691	$format = length pack $format, $len;
		1692
		1693	# bypass unshift if we already have the remaining chunk
		1694	if ($format + $len <= length $_[0]{rbuf}) {
		1695	my $data = substr $_[0]{rbuf}, $format, $len;
		1696	substr $_[0]{rbuf}, 0, $format + $len, "";
		1697	$cb->($_[0], $data);
		1698	} else {
		1699	# remove prefix
		1700	substr $_[0]{rbuf}, 0, $format, "";
		1701
		1702	# read remaining chunk
		1703	$_[0]->unshift_read (chunk => $len, $cb);
		1704	}
		1705
		1706	1
		1707	}
		1708	};
		1709
		1710	=item json => $cb->($handle, $hash_or_arrayref)
		1711
		1712	Reads a JSON object or array, decodes it and passes it to the
		1713	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1714
		1715	If a C<json> object was passed to the constructor, then that will be
		1716	used for the final decode, otherwise it will create a L<JSON::XS> or
		1717	L<JSON::PP> coder object expecting UTF-8.
		1718
		1719	This read type uses the incremental parser available with JSON version
		1720	2.09 (and JSON::XS version 2.2) and above.
		1721
		1722	Since JSON texts are fully self-delimiting, the C<json> read and write
		1723	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1724	the C<json> write type description, above, for an actual example.
		1725
		1726	=cut
		1727
		1728	register_read_type json => sub {
		1729	my ($self, $cb) = @_;
		1730
		1731	my $json = $self->{json} ||= json_coder;
		1732
		1733	my $data;
		1734
		1735	sub {
		1736	my $ref = eval { $json->incr_parse ($_[0]{rbuf}) };
		1737
		1738	if ($ref) {
		1739	$_[0]{rbuf} = $json->incr_text;
		1740	$json->incr_text = "";
		1741	$cb->($_[0], $ref);
		1742
		1743	1
		1744	} elsif ($@) {
		1745	# error case
		1746	$json->incr_skip;
		1747
		1748	$_[0]{rbuf} = $json->incr_text;
		1749	$json->incr_text = "";
		1750
		1751	$_[0]->_error (Errno::EBADMSG);
		1752
		1753	()
		1754	} else {
		1755	$_[0]{rbuf} = "";
		1756
		1757	()
		1758	}
		1759	}
		1760	};
		1761
		1762	=item cbor => $cb->($handle, $scalar)
		1763
		1764	Reads a CBOR value, decodes it and passes it to the callback. When a parse
		1765	error occurs, an C<EBADMSG> error will be raised.
		1766
		1767	If a L<CBOR::XS> object was passed to the constructor, then that will be
		1768	used for the final decode, otherwise it will create a CBOR coder without
		1769	enabling any options.
		1770
		1771	You have to provide a dependency to L<CBOR::XS> on your own: this module
		1772	will load the L<CBOR::XS> module, but AnyEvent does not depend on it
		1773	itself.
		1774
		1775	Since CBOR values are fully self-delimiting, the C<cbor> read and write
		1776	types are an ideal simple RPC protocol: just exchange CBOR datagrams. See
		1777	the C<cbor> write type description, above, for an actual example.
		1778
		1779	=cut
		1780
		1781	register_read_type cbor => sub {
		1782	my ($self, $cb) = @_;
		1783
		1784	my $cbor = $self->{cbor} ||= cbor_coder;
		1785
		1786	my $data;
		1787
		1788	sub {
		1789	my (@value) = eval { $cbor->incr_parse ($_[0]{rbuf}) };
		1790
		1791	if (@value) {
		1792	$cb->($_[0], @value);
		1793
		1794	1
		1795	} elsif ($@) {
		1796	# error case
		1797	$cbor->incr_reset;
		1798
		1799	$_[0]->_error (Errno::EBADMSG);
		1800
		1801	()
		1802	} else {
		1803	()
		1804	}
		1805	}
		1806	};
		1807
		1808	=item storable => $cb->($handle, $ref)
		1809
		1810	Deserialises a L<Storable> frozen representation as written by the
		1811	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1812	data).
		1813
		1814	Raises C<EBADMSG> error if the data could not be decoded.
		1815
		1816	=cut
		1817
		1818	register_read_type storable => sub {
		1819	my ($self, $cb) = @_;
		1820
		1821	require Storable unless $Storable::VERSION;
		1822
		1823	sub {
		1824	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1825	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1826	or return;
		1827
		1828	my $format = length pack "w", $len;
		1829
		1830	# bypass unshift if we already have the remaining chunk
		1831	if ($format + $len <= length $_[0]{rbuf}) {
		1832	my $data = substr $_[0]{rbuf}, $format, $len;
		1833	substr $_[0]{rbuf}, 0, $format + $len, "";
		1834
		1835	eval { $cb->($_[0], Storable::thaw ($data)); 1 }
		1836	or return $_[0]->_error (Errno::EBADMSG);
		1837	} else {
		1838	# remove prefix
		1839	substr $_[0]{rbuf}, 0, $format, "";
		1840
		1841	# read remaining chunk
		1842	$_[0]->unshift_read (chunk => $len, sub {
		1843	eval { $cb->($_[0], Storable::thaw ($_[1])); 1 }
		1844	or $_[0]->_error (Errno::EBADMSG);
		1845	});
		1846	}
		1847
		1848	1
		1849	}
		1850	};
		1851
		1852	=item tls_detect => $cb->($handle, $detect, $major, $minor)
		1853
		1854	Checks the input stream for a valid SSL or TLS handshake TLSPaintext
		1855	record without consuming anything. Only SSL version 3 or higher
		1856	is handled, up to the fictituous protocol 4.x (but both SSL3+ and
		1857	SSL2-compatible framing is supported).
		1858
		1859	If it detects that the input data is likely TLS, it calls the callback
		1860	with a true value for C<$detect> and the (on-wire) TLS version as second
		1861	and third argument (C<$major> is C<3>, and C<$minor> is 0..3 for SSL
		1862	3.0, TLS 1.0, 1.1 and 1.2, respectively). If it detects the input to
		1863	be definitely not TLS, it calls the callback with a false value for
		1864	C<$detect>.
		1865
		1866	The callback could use this information to decide whether or not to start
		1867	TLS negotiation.
		1868
		1869	In all cases the data read so far is passed to the following read
		1870	handlers.
		1871
		1872	Usually you want to use the C<tls_autostart> read type instead.
		1873
		1874	If you want to design a protocol that works in the presence of TLS
		1875	dtection, make sure that any non-TLS data doesn't start with the octet 22
		1876	(ASCII SYN, 16 hex) or 128-255 (i.e. highest bit set). The checks this
		1877	read type does are a bit more strict, but might losen in the future to
		1878	accomodate protocol changes.
		1879
		1880	This read type does not rely on L<AnyEvent::TLS> (and thus, not on
		1881	L<Net::SSLeay>).
		1882
		1883	=item tls_autostart => [$tls_ctx, ]$tls
		1884
		1885	Tries to detect a valid SSL or TLS handshake. If one is detected, it tries
		1886	to start tls by calling C<starttls> with the given arguments.
		1887
		1888	In practise, C<$tls> must be C<accept>, or a Net::SSLeay context that has
		1889	been configured to accept, as servers do not normally send a handshake on
		1890	their own and ths cannot be detected in this way.
		1891
		1892	See C<tls_detect> above for more details.
		1893
		1894	Example: give the client a chance to start TLS before accepting a text
		1895	line.
		1896
		1897	$hdl->push_read (tls_autostart => "accept");
		1898	$hdl->push_read (line => sub {
		1899	print "received ", ($_[0]{tls} ? "encrypted" : "cleartext"), " <$_[1]>\n";
		1900	});
		1901
		1902	=cut
		1903
		1904	register_read_type tls_detect => sub {
		1905	my ($self, $cb) = @_;
		1906
		1907	sub {
		1908	# this regex matches a full or partial tls record
		1909	if (
		1910	# ssl3+: type(22=handshake) major(=3) minor(any) length_hi
		1911	$self->{rbuf} =~ /^(?:\z| \x16 (\z| [\x03\x04] (?:\z| . (?:\z| [\x00-\x40] ))))/xs
		1912	# ssl2 comapatible: len_hi len_lo type(1) major minor dummy(forlength)
		1913	or $self->{rbuf} =~ /^(?:\z| [\x80-\xff] (?:\z| . (?:\z| \x01 (\z| [\x03\x04] (?:\z| . (?:\z| . ))))))/xs
		1914	) {
		1915	return if 3 != length $1; # partial match, can't decide yet
		1916
		1917	# full match, valid TLS record
		1918	my ($major, $minor) = unpack "CC", $1;
		1919	$cb->($self, "accept", $major, $minor);
		1920	} else {
		1921	# mismatch == guaranteed not TLS
		1922	$cb->($self, undef);
		1923	}
		1924
		1925	1
		1926	}
		1927	};
		1928
		1929	register_read_type tls_autostart => sub {
		1930	my ($self, @tls) = @_;
		1931
		1932	$RH{tls_detect}($self, sub {
		1933	return unless $_[1];
		1934	$_[0]->starttls (@tls);
158	}	1935	})
159		1936	};
160	$self->{on_read_w} =	1937
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1938	=back
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1939
163	my $rbuf_len = length $self->{rbuf};	1940	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
164	my $l;	1941
		1942	Instead of one of the predefined types, you can also specify the name
		1943	of a package. AnyEvent will try to load the package and then expects to
		1944	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1945	progressively tries to load the parent package until it either finds the
		1946	function (good) or runs out of packages (bad).
		1947
		1948	Whenever this type is used, C<push_read> will invoke the function with the
		1949	handle object, the original callback and the remaining arguments.
		1950
		1951	The function is supposed to return a callback (usually a closure) that
		1952	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1953	mentally treat the function as a "configurable read type to read callback"
		1954	converter.
		1955
		1956	It should invoke the original callback when it is done reading (remember
		1957	to pass C<$handle> as first argument as all other callbacks do that,
		1958	although there is no strict requirement on this).
		1959
		1960	For examples, see the source of this module (F<perldoc -m
		1961	AnyEvent::Handle>, search for C<register_read_type>)).
		1962
		1963	=item $handle->stop_read
		1964
		1965	=item $handle->start_read
		1966
		1967	In rare cases you actually do not want to read anything from the
		1968	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1969	any queued callbacks will be executed then. To start reading again, call
		1970	C<start_read>.
		1971
		1972	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1973	you change the C<on_read> callback or push/unshift a read callback, and it
		1974	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1975	there are any read requests in the queue.
		1976
		1977	In older versions of this module (<= 5.3), these methods had no effect,
		1978	as TLS does not support half-duplex connections. In current versions they
		1979	work as expected, as this behaviour is required to avoid certain resource
		1980	attacks, where the program would be forced to read (and buffer) arbitrary
		1981	amounts of data before being able to send some data. The drawback is that
		1982	some readings of the the SSL/TLS specifications basically require this
		1983	attack to be working, as SSL/TLS implementations might stall sending data
		1984	during a rehandshake.
		1985
		1986	As a guideline, during the initial handshake, you should not stop reading,
		1987	and as a client, it might cause problems, depending on your application.
		1988
		1989	=cut
		1990
		1991	sub stop_read {
		1992	my ($self) = @_;
		1993
		1994	delete $self->{_rw};
		1995	}
		1996
		1997	sub start_read {
		1998	my ($self) = @_;
		1999
		2000	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
		2001	Scalar::Util::weaken $self;
		2002
		2003	$self->{_rw} = AE::io $self->{fh}, 0, sub {
		2004	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		2005	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
		2006
		2007	if ($len > 0) {
		2008	$self->{_activity} = $self->{_ractivity} = AE::now;
		2009
		2010	if ($self->{tls}) {
		2011	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		2012
		2013	&_dotls ($self);
		2014	} else {
		2015	$self->_drain_rbuf;
		2016	}
		2017
165	if (defined $self->{read_size}) {	2018	if ($len == $self->{read_size}) {
166	$l = sysread $self->{fh}, $self->{rbuf},	2019	$self->{read_size} *= 2;
167	($self->{read_size} - $rbuf_len), $rbuf_len;	2020	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		2021	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		2022	}
		2023
		2024	} elsif (defined $len) {
		2025	delete $self->{_rw};
		2026	$self->{_eof} = 1;
		2027	$self->_drain_rbuf;
		2028
		2029	} elsif ($! != EAGAIN && $! != EINTR && $! != EWOULDBLOCK && $! != WSAEWOULDBLOCK) {
		2030	return $self->_error ($!, 1);
		2031	}
		2032	};
		2033	}
		2034	}
		2035
		2036	our $ERROR_SYSCALL;
		2037	our $ERROR_WANT_READ;
		2038
		2039	sub _tls_error {
		2040	my ($self, $err) = @_;
		2041
		2042	return $self->_error ($!, 1)
		2043	if $err == Net::SSLeay::ERROR_SYSCALL ();
		2044
		2045	my $err = Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		2046
		2047	# reduce error string to look less scary
		2048	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		2049
		2050	if ($self->{_on_starttls}) {
		2051	(delete $self->{_on_starttls})->($self, undef, $err);
		2052	&_freetls;
		2053	} else {
		2054	&_freetls;
		2055	$self->_error (Errno::EPROTO, 1, $err);
		2056	}
		2057	}
		2058
		2059	# poll the write BIO and send the data if applicable
		2060	# also decode read data if possible
		2061	# this is basiclaly our TLS state machine
		2062	# more efficient implementations are possible with openssl,
		2063	# but not with the buggy and incomplete Net::SSLeay.
		2064	sub _dotls {
		2065	my ($self) = @_;
		2066
		2067	my $tmp;
		2068
		2069	while (length $self->{_tls_wbuf}) {
		2070	if (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) <= 0) {
		2071	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		2072
		2073	return $self->_tls_error ($tmp)
		2074	if $tmp != $ERROR_WANT_READ
		2075	&& ($tmp != $ERROR_SYSCALL || $!);
		2076
		2077	last;
		2078	}
		2079
		2080	substr $self->{_tls_wbuf}, 0, $tmp, "";
		2081	}
		2082
		2083	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		2084	unless (length $tmp) {
		2085	$self->{_on_starttls}
		2086	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		2087	&_freetls;
		2088
		2089	if ($self->{on_stoptls}) {
		2090	$self->{on_stoptls}($self);
		2091	return;
168	} else {	2092	} else {
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	2093	# 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};	2094	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];	2095	$self->{_eof} = 1;
324	}	2096	}
325	}	2097	}
326	return;
327	}
328		2098
329	my $wba = shift @{$self->{write_bufs}}	2099	$self->{_tls_rbuf} .= $tmp;
330	or return;	2100	$self->_drain_rbuf;
331		2101	$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	}	2102	}
337		2103
338	$self->{wbuf} = $wba->[0];	2104	$tmp = Net::SSLeay::get_error ($self->{tls}, -1); # -1 is not neccessarily correct, but Net::SSLeay doesn't tell us
339	$self->{write_cb} = $wba->[1];	2105	return $self->_tls_error ($tmp)
		2106	if $tmp != $ERROR_WANT_READ
		2107	&& ($tmp != $ERROR_SYSCALL || $!);
340		2108
341	$self->{write_w} =	2109	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
342	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	2110	$self->{wbuf} .= $tmp;
343	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	2111	$self->_drain_wbuf;
		2112	$self->{tls} or return; # tls session might have gone away in callback
		2113	}
344		2114
345	if (not defined $l) {	2115	$self->{_on_starttls}
346	return if $! == EAGAIN || $! == EINTR;	2116	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
347	delete $self->{write_w};	2117	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
348	$self->{on_error}->($self) if $self->{on_error};	2118	}
349		2119
		2120	=item $handle->starttls ($tls[, $tls_ctx])
		2121
		2122	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		2123	object is created, you can also do that at a later time by calling
		2124	C<starttls>. See the C<tls> constructor argument for general info.
		2125
		2126	Starting TLS is currently an asynchronous operation - when you push some
		2127	write data and then call C<< ->starttls >> then TLS negotiation will start
		2128	immediately, after which the queued write data is then sent. This might
		2129	change in future versions, so best make sure you have no outstanding write
		2130	data when calling this method.
		2131
		2132	The first argument is the same as the C<tls> constructor argument (either
		2133	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		2134
		2135	The second argument is the optional C<AnyEvent::TLS> object that is used
		2136	when AnyEvent::Handle has to create its own TLS connection object, or
		2137	a hash reference with C<< key => value >> pairs that will be used to
		2138	construct a new context.
		2139
		2140	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		2141	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		2142	changed to your liking. Note that the handshake might have already started
		2143	when this function returns.
		2144
		2145	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		2146	handshakes on the same stream. It is best to not attempt to use the
		2147	stream after stopping TLS.
		2148
		2149	This method may invoke callbacks (and therefore the handle might be
		2150	destroyed after it returns).
		2151
		2152	=cut
		2153
		2154	our %TLS_CACHE; #TODO not yet documented, should we?
		2155
		2156	sub starttls {
		2157	my ($self, $tls, $ctx) = @_;
		2158
		2159	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		2160	if $self->{tls};
		2161
		2162	unless (defined $AnyEvent::TLS::VERSION) {
		2163	eval {
		2164	require Net::SSLeay;
		2165	require AnyEvent::TLS;
		2166	1
		2167	} or return $self->_error (Errno::EPROTO, 1, "TLS support not available on this system");
		2168	}
		2169
		2170	$self->{tls} = $tls;
		2171	$self->{tls_ctx} = $ctx if @_ > 2;
		2172
		2173	return unless $self->{fh};
		2174
		2175	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		2176	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		2177
		2178	$tls = delete $self->{tls};
		2179	$ctx = $self->{tls_ctx};
		2180
		2181	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		2182
		2183	if ("HASH" eq ref $ctx) {
		2184	if ($ctx->{cache}) {
		2185	my $key = $ctx+0;
		2186	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
350	} else {	2187	} else {
		2188	$ctx = new AnyEvent::TLS %$ctx;
		2189	}
		2190	}
		2191
		2192	$self->{tls_ctx} = $ctx || TLS_CTX ();
		2193	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
		2194
		2195	# basically, this is deep magic (because SSL_read should have the same issues)
		2196	# but the openssl maintainers basically said: "trust us, it just works".
		2197	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		2198	# and mismaintained ssleay-module didn't offer them for a decade or so).
		2199	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		2200	#
		2201	# in short: this is a mess.
		2202	#
		2203	# note that we do not try to keep the length constant between writes as we are required to do.
		2204	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		2205	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		2206	# have identity issues in that area.
		2207	# Net::SSLeay::set_mode ($ssl,
		2208	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		2209	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		2210	Net::SSLeay::set_mode ($tls, 1|2);
		2211
		2212	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		2213	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		2214
		2215	Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
		2216	$self->{rbuf} = "";
		2217
		2218	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
		2219
		2220	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
		2221	if $self->{on_starttls};
		2222
		2223	&_dotls; # need to trigger the initial handshake
		2224	$self->start_read; # make sure we actually do read
		2225	}
		2226
		2227	=item $handle->stoptls
		2228
		2229	Shuts down the SSL connection - this makes a proper EOF handshake by
		2230	sending a close notify to the other side, but since OpenSSL doesn't
		2231	support non-blocking shut downs, it is not guaranteed that you can re-use
		2232	the stream afterwards.
		2233
		2234	This method may invoke callbacks (and therefore the handle might be
		2235	destroyed after it returns).
		2236
		2237	=cut
		2238
		2239	sub stoptls {
		2240	my ($self) = @_;
		2241
		2242	if ($self->{tls} && $self->{fh}) {
		2243	Net::SSLeay::shutdown ($self->{tls});
		2244
		2245	&_dotls;
		2246
		2247	# # we don't give a shit. no, we do, but we can't. no...#d#
		2248	# # we, we... have to use openssl :/#d#
		2249	# &_freetls;#d#
		2250	}
		2251	}
		2252
		2253	sub _freetls {
		2254	my ($self) = @_;
		2255
		2256	return unless $self->{tls};
		2257
		2258	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2259	if $self->{tls} > 0;
		2260
		2261	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		2262	}
		2263
		2264	=item $handle->resettls
		2265
		2266	This rarely-used method simply resets and TLS state on the handle, usually
		2267	causing data loss.
		2268
		2269	One case where it may be useful is when you want to skip over the data in
		2270	the stream but you are not interested in interpreting it, so data loss is
		2271	no concern.
		2272
		2273	=cut
		2274
		2275	*resettls = \&_freetls;
		2276
		2277	sub DESTROY {
		2278	my ($self) = @_;
		2279
		2280	&_freetls;
		2281
		2282	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		2283
		2284	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2285	my $fh = delete $self->{fh};
		2286	my $wbuf = delete $self->{wbuf};
		2287
		2288	my @linger;
		2289
		2290	push @linger, AE::io $fh, 1, sub {
		2291	my $len = syswrite $fh, $wbuf, length $wbuf;
		2292
		2293	if ($len > 0) {
351	substr $self->{wbuf}, 0, $l, '';	2294	substr $wbuf, 0, $len, "";
352		2295	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != EWOULDBLOCK && $! != WSAEWOULDBLOCK)) {
353	if (length ($self->{wbuf}) == 0) {	2296	@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	}	2297	}
		2298	};
		2299	push @linger, AE::timer $linger, 0, sub {
		2300	@linger = ();
		2301	};
		2302	}
		2303	}
		2304
		2305	=item $handle->destroy
		2306
		2307	Shuts down the handle object as much as possible - this call ensures that
		2308	no further callbacks will be invoked and as many resources as possible
		2309	will be freed. Any method you will call on the handle object after
		2310	destroying it in this way will be silently ignored (and it will return the
		2311	empty list).
		2312
		2313	Normally, you can just "forget" any references to an AnyEvent::Handle
		2314	object and it will simply shut down. This works in fatal error and EOF
		2315	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2316	callback, so when you want to destroy the AnyEvent::Handle object from
		2317	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2318	that case.
		2319
		2320	Destroying the handle object in this way has the advantage that callbacks
		2321	will be removed as well, so if those are the only reference holders (as
		2322	is common), then one doesn't need to do anything special to break any
		2323	reference cycles.
		2324
		2325	The handle might still linger in the background and write out remaining
		2326	data, as specified by the C<linger> option, however.
		2327
		2328	=cut
		2329
		2330	sub destroy {
		2331	my ($self) = @_;
		2332
		2333	$self->DESTROY;
		2334	%$self = ();
		2335	bless $self, "AnyEvent::Handle::destroyed";
		2336	}
		2337
		2338	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2339	#nop
		2340	}
		2341
		2342	=item $handle->destroyed
		2343
		2344	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2345	->destroy >>, true otherwise.
		2346
		2347	Can be useful to decide whether the handle is still valid after some
		2348	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2349	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2350	can destroy the handle, so work can be avoided by checking sometimes:
		2351
		2352	$hdl->starttls ("accept");
		2353	return if $hdl->destroyed;
		2354	$hdl->push_write (...
		2355
		2356	Note that the call to C<push_write> will silently be ignored if the handle
		2357	has been destroyed, so often you can just ignore the possibility of the
		2358	handle being destroyed.
		2359
		2360	=cut
		2361
		2362	sub destroyed { 0 }
		2363	sub AnyEvent::Handle::destroyed::destroyed { 1 }
		2364
		2365	=item AnyEvent::Handle::TLS_CTX
		2366
		2367	This function creates and returns the AnyEvent::TLS object used by default
		2368	for TLS mode.
		2369
		2370	The context is created by calling L<AnyEvent::TLS> without any arguments.
		2371
		2372	=cut
		2373
		2374	our $TLS_CTX;
		2375
		2376	sub TLS_CTX() {
		2377	$TLS_CTX ||= do {
		2378	require AnyEvent::TLS;
		2379
		2380	new AnyEvent::TLS
		2381	}
		2382	}
		2383
		2384	=back
		2385
		2386
		2387	=head1 NONFREQUENTLY ASKED QUESTIONS
		2388
		2389	=over 4
		2390
		2391	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2392	still get further invocations!
		2393
		2394	That's because AnyEvent::Handle keeps a reference to itself when handling
		2395	read or write callbacks.
		2396
		2397	It is only safe to "forget" the reference inside EOF or error callbacks,
		2398	from within all other callbacks, you need to explicitly call the C<<
		2399	->destroy >> method.
		2400
		2401	=item Why is my C<on_eof> callback never called?
		2402
		2403	Probably because your C<on_error> callback is being called instead: When
		2404	you have outstanding requests in your read queue, then an EOF is
		2405	considered an error as you clearly expected some data.
		2406
		2407	To avoid this, make sure you have an empty read queue whenever your handle
		2408	is supposed to be "idle" (i.e. connection closes are O.K.). You can set
		2409	an C<on_read> handler that simply pushes the first read requests in the
		2410	queue.
		2411
		2412	See also the next question, which explains this in a bit more detail.
		2413
		2414	=item How can I serve requests in a loop?
		2415
		2416	Most protocols consist of some setup phase (authentication for example)
		2417	followed by a request handling phase, where the server waits for requests
		2418	and handles them, in a loop.
		2419
		2420	There are two important variants: The first (traditional, better) variant
		2421	handles requests until the server gets some QUIT command, causing it to
		2422	close the connection first (highly desirable for a busy TCP server). A
		2423	client dropping the connection is an error, which means this variant can
		2424	detect an unexpected detection close.
		2425
		2426	To handle this case, always make sure you have a non-empty read queue, by
		2427	pushing the "read request start" handler on it:
		2428
		2429	# we assume a request starts with a single line
		2430	my @start_request; @start_request = (line => sub {
		2431	my ($hdl, $line) = @_;
		2432
		2433	... handle request
		2434
		2435	# push next request read, possibly from a nested callback
		2436	$hdl->push_read (@start_request);
		2437	});
		2438
		2439	# auth done, now go into request handling loop
		2440	# now push the first @start_request
		2441	$hdl->push_read (@start_request);
		2442
		2443	By always having an outstanding C<push_read>, the handle always expects
		2444	some data and raises the C<EPIPE> error when the connction is dropped
		2445	unexpectedly.
		2446
		2447	The second variant is a protocol where the client can drop the connection
		2448	at any time. For TCP, this means that the server machine may run out of
		2449	sockets easier, and in general, it means you cannot distinguish a protocl
		2450	failure/client crash from a normal connection close. Nevertheless, these
		2451	kinds of protocols are common (and sometimes even the best solution to the
		2452	problem).
		2453
		2454	Having an outstanding read request at all times is possible if you ignore
		2455	C<EPIPE> errors, but this doesn't help with when the client drops the
		2456	connection during a request, which would still be an error.
		2457
		2458	A better solution is to push the initial request read in an C<on_read>
		2459	callback. This avoids an error, as when the server doesn't expect data
		2460	(i.e. is idly waiting for the next request, an EOF will not raise an
		2461	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2462	and simpler:
		2463
		2464	# auth done, now go into request handling loop
		2465	$hdl->on_read (sub {
		2466	my ($hdl) = @_;
		2467
		2468	# called each time we receive data but the read queue is empty
		2469	# simply start read the request
		2470
		2471	$hdl->push_read (line => sub {
		2472	my ($hdl, $line) = @_;
		2473
		2474	... handle request
		2475
		2476	# do nothing special when the request has been handled, just
		2477	# let the request queue go empty.
363	});	2478	});
364	}	2479	});
		2480
		2481	=item I get different callback invocations in TLS mode/Why can't I pause
		2482	reading?
		2483
		2484	Unlike, say, TCP, TLS connections do not consist of two independent
		2485	communication channels, one for each direction. Or put differently, the
		2486	read and write directions are not independent of each other: you cannot
		2487	write data unless you are also prepared to read, and vice versa.
		2488
		2489	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2490	callback invocations when you are not expecting any read data - the reason
		2491	is that AnyEvent::Handle always reads in TLS mode.
		2492
		2493	During the connection, you have to make sure that you always have a
		2494	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2495	connection (or when you no longer want to use it) you can call the
		2496	C<destroy> method.
		2497
		2498	=item How do I read data until the other side closes the connection?
		2499
		2500	If you just want to read your data into a perl scalar, the easiest way
		2501	to achieve this is by setting an C<on_read> callback that does nothing,
		2502	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2503	will be in C<$_[0]{rbuf}>:
		2504
		2505	$handle->on_read (sub { });
		2506	$handle->on_eof (undef);
		2507	$handle->on_error (sub {
		2508	my $data = delete $_[0]{rbuf};
		2509	});
		2510
		2511	Note that this example removes the C<rbuf> member from the handle object,
		2512	which is not normally allowed by the API. It is expressly permitted in
		2513	this case only, as the handle object needs to be destroyed afterwards.
		2514
		2515	The reason to use C<on_error> is that TCP connections, due to latencies
		2516	and packets loss, might get closed quite violently with an error, when in
		2517	fact all data has been received.
		2518
		2519	It is usually better to use acknowledgements when transferring data,
		2520	to make sure the other side hasn't just died and you got the data
		2521	intact. This is also one reason why so many internet protocols have an
		2522	explicit QUIT command.
		2523
		2524	=item I don't want to destroy the handle too early - how do I wait until
		2525	all data has been written?
		2526
		2527	After writing your last bits of data, set the C<on_drain> callback
		2528	and destroy the handle in there - with the default setting of
		2529	C<low_water_mark> this will be called precisely when all data has been
		2530	written to the socket:
		2531
		2532	$handle->push_write (...);
		2533	$handle->on_drain (sub {
		2534	AE::log debug => "All data submitted to the kernel.";
		2535	undef $handle;
		2536	});
		2537
		2538	If you just want to queue some data and then signal EOF to the other side,
		2539	consider using C<< ->push_shutdown >> instead.
		2540
		2541	=item I want to contact a TLS/SSL server, I don't care about security.
		2542
		2543	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2544	connect to it and then create the AnyEvent::Handle with the C<tls>
		2545	parameter:
		2546
		2547	tcp_connect $host, $port, sub {
		2548	my ($fh) = @_;
		2549
		2550	my $handle = new AnyEvent::Handle
		2551	fh => $fh,
		2552	tls => "connect",
		2553	on_error => sub { ... };
		2554
		2555	$handle->push_write (...);
		2556	};
		2557
		2558	=item I want to contact a TLS/SSL server, I do care about security.
		2559
		2560	Then you should additionally enable certificate verification, including
		2561	peername verification, if the protocol you use supports it (see
		2562	L<AnyEvent::TLS>, C<verify_peername>).
		2563
		2564	E.g. for HTTPS:
		2565
		2566	tcp_connect $host, $port, sub {
		2567	my ($fh) = @_;
		2568
		2569	my $handle = new AnyEvent::Handle
		2570	fh => $fh,
		2571	peername => $host,
		2572	tls => "connect",
		2573	tls_ctx => { verify => 1, verify_peername => "https" },
		2574	...
		2575
		2576	Note that you must specify the hostname you connected to (or whatever
		2577	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2578	peername verification will be done.
		2579
		2580	The above will use the system-dependent default set of trusted CA
		2581	certificates. If you want to check against a specific CA, add the
		2582	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2583
		2584	tls_ctx => {
		2585	verify => 1,
		2586	verify_peername => "https",
		2587	ca_file => "my-ca-cert.pem",
		2588	},
		2589
		2590	=item I want to create a TLS/SSL server, how do I do that?
		2591
		2592	Well, you first need to get a server certificate and key. You have
		2593	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2594	self-signed certificate (cheap. check the search engine of your choice,
		2595	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2596	nice program for that purpose).
		2597
		2598	Then create a file with your private key (in PEM format, see
		2599	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2600	file should then look like this:
		2601
		2602	-----BEGIN RSA PRIVATE KEY-----
		2603	...header data
		2604	... lots of base64'y-stuff
		2605	-----END RSA PRIVATE KEY-----
		2606
		2607	-----BEGIN CERTIFICATE-----
		2608	... lots of base64'y-stuff
		2609	-----END CERTIFICATE-----
		2610
		2611	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2612	specify this file as C<cert_file>:
		2613
		2614	tcp_server undef, $port, sub {
		2615	my ($fh) = @_;
		2616
		2617	my $handle = new AnyEvent::Handle
		2618	fh => $fh,
		2619	tls => "accept",
		2620	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2621	...
		2622
		2623	When you have intermediate CA certificates that your clients might not
		2624	know about, just append them to the C<cert_file>.
365		2625
366	=back	2626	=back
367		2627
		2628	=head1 SUBCLASSING AnyEvent::Handle
		2629
		2630	In many cases, you might want to subclass AnyEvent::Handle.
		2631
		2632	To make this easier, a given version of AnyEvent::Handle uses these
		2633	conventions:
		2634
		2635	=over 4
		2636
		2637	=item * all constructor arguments become object members.
		2638
		2639	At least initially, when you pass a C<tls>-argument to the constructor it
		2640	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2641	mutated later on (for example C<tls> will hold the TLS connection object).
		2642
		2643	=item * other object member names are prefixed with an C<_>.
		2644
		2645	All object members not explicitly documented (internal use) are prefixed
		2646	with an underscore character, so the remaining non-C<_>-namespace is free
		2647	for use for subclasses.
		2648
		2649	=item * all members not documented here and not prefixed with an underscore
		2650	are free to use in subclasses.
		2651
		2652	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2653	member variables, but that's just life. At least it is documented.
		2654
		2655	=back
		2656
368	=head1 AUTHOR	2657	=head1 AUTHOR
369		2658
370	Robin Redeker, C<< <elmex at ta-sa.org> >>	2659	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
371		2660
372	=cut	2661	=cut
373		2662
374	1; # End of AnyEvent::Handle	2663	1
		2664

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