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Revision 1.6 by elmex, Mon Apr 28 09:27:47 2008 UTC vs.
Revision 1.96 by root, Thu Oct 2 08:10:27 2008 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	no warnings;	3	no warnings;
4	use strict;	4	use strict qw(subs vars);
5		5
6	use AnyEvent;	6	use AnyEvent ();
7	use IO::Handle;	7	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		8	use Scalar::Util ();
		9	use Carp ();
		10	use Fcntl ();
8	use Errno qw/EAGAIN EINTR/;	11	use Errno qw(EAGAIN EINTR);
9		12
10	=head1 NAME	13	=head1 NAME
11		14
12	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
13		16
14	=head1 VERSION
15
16	Version 0.01
17
18	=cut	17	=cut
19		18
20	our $VERSION = '0.01';	19	our $VERSION = 4.3;
21		20
22	=head1 SYNOPSIS	21	=head1 SYNOPSIS
23		22
24	use AnyEvent;	23	use AnyEvent;
25	use AnyEvent::Handle;	24	use AnyEvent::Handle;
26		25
27	my $cv = AnyEvent->condvar;	26	my $cv = AnyEvent->condvar;
28		27
29	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	28	my $handle =
30
31	$ae_fh->on_eof (sub { $cv->broadcast });
32
33	$ae_fh->readlines (sub {
34	my ($ae_fh, @lines) = @_;
35	for (@lines) {
36	chomp;
37	print "Line: $_";
38	}
39	});
40
41	# or use the constructor to pass the callback:
42
43	my $ae_fh2 =
44	AnyEvent::Handle->new (	29	AnyEvent::Handle->new (
45	fh => \*STDIN,	30	fh => \*STDIN,
46	on_eof => sub {	31	on_eof => sub {
47	$cv->broadcast;	32	$cv->broadcast;
48	},	33	},
		34	);
		35
		36	# send some request line
		37	$handle->push_write ("getinfo\015\012");
		38
		39	# read the response line
		40	$handle->push_read (line => sub {
		41	my ($handle, $line) = @_;
		42	warn "read line <$line>\n";
		43	$cv->send;
		44	});
		45
		46	$cv->recv;
		47
		48	=head1 DESCRIPTION
		49
		50	This module is a helper module to make it easier to do event-based I/O on
		51	filehandles. For utility functions for doing non-blocking connects and accepts
		52	on sockets see L<AnyEvent::Util>.
		53
		54	The L<AnyEvent::Intro> tutorial contains some well-documented
		55	AnyEvent::Handle examples.
		56
		57	In the following, when the documentation refers to of "bytes" then this
		58	means characters. As sysread and syswrite are used for all I/O, their
		59	treatment of characters applies to this module as well.
		60
		61	All callbacks will be invoked with the handle object as their first
		62	argument.
		63
		64	=head2 SIGPIPE is not handled by this module
		65
		66	SIGPIPE is not handled by this module, so one of the practical
		67	requirements of using it is to ignore SIGPIPE (C<$SIG{PIPE} =
		68	'IGNORE'>). At least, this is highly recommend in a networked program: If
		69	you use AnyEvent::Handle in a filter program (like sort), exiting on
		70	SIGPIPE is probably the right thing to do.
		71
		72	=head1 METHODS
		73
		74	=over 4
		75
		76	=item B<new (%args)>
		77
		78	The constructor supports these arguments (all as key => value pairs).
		79
		80	=over 4
		81
		82	=item fh => $filehandle [MANDATORY]
		83
		84	The filehandle this L<AnyEvent::Handle> object will operate on.
		85
		86	NOTE: The filehandle will be set to non-blocking mode (using
		87	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		88	that mode.
		89
		90	=item on_eof => $cb->($handle)
		91
		92	Set the callback to be called when an end-of-file condition is detected,
		93	i.e. in the case of a socket, when the other side has closed the
		94	connection cleanly.
		95
		96	For sockets, this just means that the other side has stopped sending data,
		97	you can still try to write data, and, in fact, one can return from the eof
		98	callback and continue writing data, as only the read part has been shut
		99	down.
		100
		101	While not mandatory, it is I<highly> recommended to set an eof callback,
		102	otherwise you might end up with a closed socket while you are still
		103	waiting for data.
		104
		105	If an EOF condition has been detected but no C<on_eof> callback has been
		106	set, then a fatal error will be raised with C<$!> set to <0>.
		107
		108	=item on_error => $cb->($handle, $fatal)
		109
		110	This is the error callback, which is called when, well, some error
		111	occured, such as not being able to resolve the hostname, failure to
		112	connect or a read error.
		113
		114	Some errors are fatal (which is indicated by C<$fatal> being true). On
		115	fatal errors the handle object will be shut down and will not be usable
		116	(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
		117	errors are an EOF condition with active (but unsatisifable) read watchers
		118	(C<EPIPE>) or I/O errors.
		119
		120	Non-fatal errors can be retried by simply returning, but it is recommended
		121	to simply ignore this parameter and instead abondon the handle object
		122	when this callback is invoked. Examples of non-fatal errors are timeouts
		123	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		124
		125	On callback entrance, the value of C<$!> contains the operating system
		126	error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
		127
		128	While not mandatory, it is I<highly> recommended to set this callback, as
		129	you will not be notified of errors otherwise. The default simply calls
		130	C<croak>.
		131
		132	=item on_read => $cb->($handle)
		133
		134	This sets the default read callback, which is called when data arrives
		135	and no read request is in the queue (unlike read queue callbacks, this
		136	callback will only be called when at least one octet of data is in the
		137	read buffer).
		138
		139	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
		140	method or access the C<$handle->{rbuf}> member directly.
		141
		142	When an EOF condition is detected then AnyEvent::Handle will first try to
		143	feed all the remaining data to the queued callbacks and C<on_read> before
		144	calling the C<on_eof> callback. If no progress can be made, then a fatal
		145	error will be raised (with C<$!> set to C<EPIPE>).
		146
		147	=item on_drain => $cb->($handle)
		148
		149	This sets the callback that is called when the write buffer becomes empty
		150	(or when the callback is set and the buffer is empty already).
		151
		152	To append to the write buffer, use the C<< ->push_write >> method.
		153
		154	This callback is useful when you don't want to put all of your write data
		155	into the queue at once, for example, when you want to write the contents
		156	of some file to the socket you might not want to read the whole file into
		157	memory and push it into the queue, but instead only read more data from
		158	the file when the write queue becomes empty.
		159
		160	=item timeout => $fractional_seconds
		161
		162	If non-zero, then this enables an "inactivity" timeout: whenever this many
		163	seconds pass without a successful read or write on the underlying file
		164	handle, the C<on_timeout> callback will be invoked (and if that one is
		165	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		166
		167	Note that timeout processing is also active when you currently do not have
		168	any outstanding read or write requests: If you plan to keep the connection
		169	idle then you should disable the timout temporarily or ignore the timeout
		170	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		171	restart the timeout.
		172
		173	Zero (the default) disables this timeout.
		174
		175	=item on_timeout => $cb->($handle)
		176
		177	Called whenever the inactivity timeout passes. If you return from this
		178	callback, then the timeout will be reset as if some activity had happened,
		179	so this condition is not fatal in any way.
		180
		181	=item rbuf_max => <bytes>
		182
		183	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		184	when the read buffer ever (strictly) exceeds this size. This is useful to
		185	avoid some forms of denial-of-service attacks.
		186
		187	For example, a server accepting connections from untrusted sources should
		188	be configured to accept only so-and-so much data that it cannot act on
		189	(for example, when expecting a line, an attacker could send an unlimited
		190	amount of data without a callback ever being called as long as the line
		191	isn't finished).
		192
		193	=item autocork => <boolean>
		194
		195	When disabled (the default), then C<push_write> will try to immediately
		196	write the data to the handle, if possible. This avoids having to register
		197	a write watcher and wait for the next event loop iteration, but can
		198	be inefficient if you write multiple small chunks (on the wire, this
		199	disadvantage is usually avoided by your kernel's nagle algorithm, see
		200	C<no_delay>, but this option can save costly syscalls).
		201
		202	When enabled, then writes will always be queued till the next event loop
		203	iteration. This is efficient when you do many small writes per iteration,
		204	but less efficient when you do a single write only per iteration (or when
		205	the write buffer often is full). It also increases write latency.
		206
		207	=item no_delay => <boolean>
		208
		209	When doing small writes on sockets, your operating system kernel might
		210	wait a bit for more data before actually sending it out. This is called
		211	the Nagle algorithm, and usually it is beneficial.
		212
		213	In some situations you want as low a delay as possible, which can be
		214	accomplishd by setting this option to a true value.
		215
		216	The default is your opertaing system's default behaviour (most likely
		217	enabled), this option explicitly enables or disables it, if possible.
		218
		219	=item read_size => <bytes>
		220
		221	The default read block size (the amount of bytes this module will
		222	try to read during each loop iteration, which affects memory
		223	requirements). Default: C<8192>.
		224
		225	=item low_water_mark => <bytes>
		226
		227	Sets the amount of bytes (default: C<0>) that make up an "empty" write
		228	buffer: If the write reaches this size or gets even samller it is
		229	considered empty.
		230
		231	Sometimes it can be beneficial (for performance reasons) to add data to
		232	the write buffer before it is fully drained, but this is a rare case, as
		233	the operating system kernel usually buffers data as well, so the default
		234	is good in almost all cases.
		235
		236	=item linger => <seconds>
		237
		238	If non-zero (default: C<3600>), then the destructor of the
		239	AnyEvent::Handle object will check whether there is still outstanding
		240	write data and will install a watcher that will write this data to the
		241	socket. No errors will be reported (this mostly matches how the operating
		242	system treats outstanding data at socket close time).
		243
		244	This will not work for partial TLS data that could not be encoded
		245	yet. This data will be lost. Calling the C<stoptls> method in time might
		246	help.
		247
		248	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		249
		250	When this parameter is given, it enables TLS (SSL) mode, that means
		251	AnyEvent will start a TLS handshake as soon as the conenction has been
		252	established and will transparently encrypt/decrypt data afterwards.
		253
		254	TLS mode requires Net::SSLeay to be installed (it will be loaded
		255	automatically when you try to create a TLS handle): this module doesn't
		256	have a dependency on that module, so if your module requires it, you have
		257	to add the dependency yourself.
		258
		259	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		260	C<accept>, and for the TLS client side of a connection, use C<connect>
		261	mode.
		262
		263	You can also provide your own TLS connection object, but you have
		264	to make sure that you call either C<Net::SSLeay::set_connect_state>
		265	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		266	AnyEvent::Handle.
		267
		268	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		269
		270	=item tls_ctx => $ssl_ctx
		271
		272	Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
		273	(unless a connection object was specified directly). If this parameter is
		274	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		275
		276	=item json => JSON or JSON::XS object
		277
		278	This is the json coder object used by the C<json> read and write types.
		279
		280	If you don't supply it, then AnyEvent::Handle will create and use a
		281	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		282	texts.
		283
		284	Note that you are responsible to depend on the JSON module if you want to
		285	use this functionality, as AnyEvent does not have a dependency itself.
		286
		287	=back
		288
		289	=cut
		290
		291	sub new {
		292	my $class = shift;
		293
		294	my $self = bless { @_ }, $class;
		295
		296	$self->{fh} or Carp::croak "mandatory argument fh is missing";
		297
		298	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		299
		300	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		301	if $self->{tls};
		302
		303	$self->{_activity} = AnyEvent->now;
		304	$self->_timeout;
		305
		306	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
		307	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		308
		309	$self->start_read
		310	if $self->{on_read};
		311
		312	$self
		313	}
		314
		315	sub _shutdown {
		316	my ($self) = @_;
		317
		318	delete $self->{_tw};
		319	delete $self->{_rw};
		320	delete $self->{_ww};
		321	delete $self->{fh};
		322
		323	&_freetls;
		324
		325	delete $self->{on_read};
		326	delete $self->{_queue};
		327	}
		328
		329	sub _error {
		330	my ($self, $errno, $fatal) = @_;
		331
		332	$self->_shutdown
		333	if $fatal;
		334
		335	$! = $errno;
		336
		337	if ($self->{on_error}) {
		338	$self->{on_error}($self, $fatal);
		339	} else {
		340	Carp::croak "AnyEvent::Handle uncaught error: $!";
		341	}
		342	}
		343
		344	=item $fh = $handle->fh
		345
		346	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		347
		348	=cut
		349
		350	sub fh { $_[0]{fh} }
		351
		352	=item $handle->on_error ($cb)
		353
		354	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		355
		356	=cut
		357
		358	sub on_error {
		359	$_[0]{on_error} = $_[1];
		360	}
		361
		362	=item $handle->on_eof ($cb)
		363
		364	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		365
		366	=cut
		367
		368	sub on_eof {
		369	$_[0]{on_eof} = $_[1];
		370	}
		371
		372	=item $handle->on_timeout ($cb)
		373
		374	Replace the current C<on_timeout> callback, or disables the callback (but
		375	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		376	argument and method.
		377
		378	=cut
		379
		380	sub on_timeout {
		381	$_[0]{on_timeout} = $_[1];
		382	}
		383
		384	=item $handle->autocork ($boolean)
		385
		386	Enables or disables the current autocork behaviour (see C<autocork>
		387	constructor argument).
		388
		389	=cut
		390
		391	=item $handle->no_delay ($boolean)
		392
		393	Enables or disables the C<no_delay> setting (see constructor argument of
		394	the same name for details).
		395
		396	=cut
		397
		398	sub no_delay {
		399	$_[0]{no_delay} = $_[1];
		400
		401	eval {
		402	local $SIG{__DIE__};
		403	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		404	};
		405	}
		406
		407	#############################################################################
		408
		409	=item $handle->timeout ($seconds)
		410
		411	Configures (or disables) the inactivity timeout.
		412
		413	=cut
		414
		415	sub timeout {
		416	my ($self, $timeout) = @_;
		417
		418	$self->{timeout} = $timeout;
		419	$self->_timeout;
		420	}
		421
		422	# reset the timeout watcher, as neccessary
		423	# also check for time-outs
		424	sub _timeout {
		425	my ($self) = @_;
		426
		427	if ($self->{timeout}) {
		428	my $NOW = AnyEvent->now;
		429
		430	# when would the timeout trigger?
		431	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		432
		433	# now or in the past already?
		434	if ($after <= 0) {
		435	$self->{_activity} = $NOW;
		436
		437	if ($self->{on_timeout}) {
		438	$self->{on_timeout}($self);
		439	} else {
		440	$self->_error (&Errno::ETIMEDOUT);
		441	}
		442
		443	# callback could have changed timeout value, optimise
		444	return unless $self->{timeout};
		445
		446	# calculate new after
		447	$after = $self->{timeout};
		448	}
		449
		450	Scalar::Util::weaken $self;
		451	return unless $self; # ->error could have destroyed $self
		452
		453	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		454	delete $self->{_tw};
		455	$self->_timeout;
		456	});
		457	} else {
		458	delete $self->{_tw};
		459	}
		460	}
		461
		462	#############################################################################
		463
		464	=back
		465
		466	=head2 WRITE QUEUE
		467
		468	AnyEvent::Handle manages two queues per handle, one for writing and one
		469	for reading.
		470
		471	The write queue is very simple: you can add data to its end, and
		472	AnyEvent::Handle will automatically try to get rid of it for you.
		473
		474	When data could be written and the write buffer is shorter then the low
		475	water mark, the C<on_drain> callback will be invoked.
		476
		477	=over 4
		478
		479	=item $handle->on_drain ($cb)
		480
		481	Sets the C<on_drain> callback or clears it (see the description of
		482	C<on_drain> in the constructor).
		483
		484	=cut
		485
		486	sub on_drain {
		487	my ($self, $cb) = @_;
		488
		489	$self->{on_drain} = $cb;
		490
		491	$cb->($self)
		492	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		493	}
		494
		495	=item $handle->push_write ($data)
		496
		497	Queues the given scalar to be written. You can push as much data as you
		498	want (only limited by the available memory), as C<AnyEvent::Handle>
		499	buffers it independently of the kernel.
		500
		501	=cut
		502
		503	sub _drain_wbuf {
		504	my ($self) = @_;
		505
		506	if (!$self->{_ww} && length $self->{wbuf}) {
		507
		508	Scalar::Util::weaken $self;
		509
		510	my $cb = sub {
		511	my $len = syswrite $self->{fh}, $self->{wbuf};
		512
		513	if ($len >= 0) {
		514	substr $self->{wbuf}, 0, $len, "";
		515
		516	$self->{_activity} = AnyEvent->now;
		517
		518	$self->{on_drain}($self)
		519	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		520	&& $self->{on_drain};
		521
		522	delete $self->{_ww} unless length $self->{wbuf};
		523	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		524	$self->_error ($!, 1);
		525	}
		526	};
		527
		528	# try to write data immediately
		529	$cb->() unless $self->{autocork};
		530
		531	# if still data left in wbuf, we need to poll
		532	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		533	if length $self->{wbuf};
		534	};
		535	}
		536
		537	our %WH;
		538
		539	sub register_write_type($$) {
		540	$WH{$_[0]} = $_[1];
		541	}
		542
		543	sub push_write {
		544	my $self = shift;
		545
		546	if (@_ > 1) {
		547	my $type = shift;
		548
		549	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		550	->($self, @_);
		551	}
		552
		553	if ($self->{tls}) {
		554	$self->{_tls_wbuf} .= $_[0];
		555	&_dotls ($self);
		556	} else {
		557	$self->{wbuf} .= $_[0];
		558	$self->_drain_wbuf;
		559	}
		560	}
		561
		562	=item $handle->push_write (type => @args)
		563
		564	Instead of formatting your data yourself, you can also let this module do
		565	the job by specifying a type and type-specific arguments.
		566
		567	Predefined types are (if you have ideas for additional types, feel free to
		568	drop by and tell us):
		569
		570	=over 4
		571
		572	=item netstring => $string
		573
		574	Formats the given value as netstring
		575	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		576
		577	=cut
		578
		579	register_write_type netstring => sub {
		580	my ($self, $string) = @_;
		581
		582	(length $string) . ":$string,"
		583	};
		584
		585	=item packstring => $format, $data
		586
		587	An octet string prefixed with an encoded length. The encoding C<$format>
		588	uses the same format as a Perl C<pack> format, but must specify a single
		589	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		590	optional C<!>, C<< < >> or C<< > >> modifier).
		591
		592	=cut
		593
		594	register_write_type packstring => sub {
		595	my ($self, $format, $string) = @_;
		596
		597	pack "$format/a*", $string
		598	};
		599
		600	=item json => $array_or_hashref
		601
		602	Encodes the given hash or array reference into a JSON object. Unless you
		603	provide your own JSON object, this means it will be encoded to JSON text
		604	in UTF-8.
		605
		606	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		607	one end of a handle and read them at the other end without using any
		608	additional framing.
		609
		610	The generated JSON text is guaranteed not to contain any newlines: While
		611	this module doesn't need delimiters after or between JSON texts to be
		612	able to read them, many other languages depend on that.
		613
		614	A simple RPC protocol that interoperates easily with others is to send
		615	JSON arrays (or objects, although arrays are usually the better choice as
		616	they mimic how function argument passing works) and a newline after each
		617	JSON text:
		618
		619	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		620	$handle->push_write ("\012");
		621
		622	An AnyEvent::Handle receiver would simply use the C<json> read type and
		623	rely on the fact that the newline will be skipped as leading whitespace:
		624
		625	$handle->push_read (json => sub { my $array = $_[1]; ... });
		626
		627	Other languages could read single lines terminated by a newline and pass
		628	this line into their JSON decoder of choice.
		629
		630	=cut
		631
		632	register_write_type json => sub {
		633	my ($self, $ref) = @_;
		634
		635	require JSON;
		636
		637	$self->{json} ? $self->{json}->encode ($ref)
		638	: JSON::encode_json ($ref)
		639	};
		640
		641	=item storable => $reference
		642
		643	Freezes the given reference using L<Storable> and writes it to the
		644	handle. Uses the C<nfreeze> format.
		645
		646	=cut
		647
		648	register_write_type storable => sub {
		649	my ($self, $ref) = @_;
		650
		651	require Storable;
		652
		653	pack "w/a*", Storable::nfreeze ($ref)
		654	};
		655
		656	=back
		657
		658	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		659
		660	This function (not method) lets you add your own types to C<push_write>.
		661	Whenever the given C<type> is used, C<push_write> will invoke the code
		662	reference with the handle object and the remaining arguments.
		663
		664	The code reference is supposed to return a single octet string that will
		665	be appended to the write buffer.
		666
		667	Note that this is a function, and all types registered this way will be
		668	global, so try to use unique names.
		669
		670	=cut
		671
		672	#############################################################################
		673
		674	=back
		675
		676	=head2 READ QUEUE
		677
		678	AnyEvent::Handle manages two queues per handle, one for writing and one
		679	for reading.
		680
		681	The read queue is more complex than the write queue. It can be used in two
		682	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		683	a queue.
		684
		685	In the simple case, you just install an C<on_read> callback and whenever
		686	new data arrives, it will be called. You can then remove some data (if
		687	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		688	leave the data there if you want to accumulate more (e.g. when only a
		689	partial message has been received so far).
		690
		691	In the more complex case, you want to queue multiple callbacks. In this
		692	case, AnyEvent::Handle will call the first queued callback each time new
		693	data arrives (also the first time it is queued) and removes it when it has
		694	done its job (see C<push_read>, below).
		695
		696	This way you can, for example, push three line-reads, followed by reading
		697	a chunk of data, and AnyEvent::Handle will execute them in order.
		698
		699	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		700	the specified number of bytes which give an XML datagram.
		701
		702	# in the default state, expect some header bytes
		703	$handle->on_read (sub {
		704	# some data is here, now queue the length-header-read (4 octets)
		705	shift->unshift_read (chunk => 4, sub {
		706	# header arrived, decode
		707	my $len = unpack "N", $_[1];
		708
		709	# now read the payload
		710	shift->unshift_read (chunk => $len, sub {
		711	my $xml = $_[1];
		712	# handle xml
		713	});
		714	});
		715	});
		716
		717	Example 2: Implement a client for a protocol that replies either with "OK"
		718	and another line or "ERROR" for the first request that is sent, and 64
		719	bytes for the second request. Due to the availability of a queue, we can
		720	just pipeline sending both requests and manipulate the queue as necessary
		721	in the callbacks.
		722
		723	When the first callback is called and sees an "OK" response, it will
		724	C<unshift> another line-read. This line-read will be queued I<before> the
		725	64-byte chunk callback.
		726
		727	# request one, returns either "OK + extra line" or "ERROR"
		728	$handle->push_write ("request 1\015\012");
		729
		730	# we expect "ERROR" or "OK" as response, so push a line read
		731	$handle->push_read (line => sub {
		732	# if we got an "OK", we have to _prepend_ another line,
		733	# so it will be read before the second request reads its 64 bytes
		734	# which are already in the queue when this callback is called
		735	# we don't do this in case we got an error
		736	if ($_[1] eq "OK") {
49	on_readline => sub {	737	$_[0]->unshift_read (line => sub {
50	my ($ae_fh, @lines) = @_;	738	my $response = $_[1];
51	for (@lines) {	739	...
52	chomp;	740	});
53	print "Line: $_";	741	}
		742	});
		743
		744	# request two, simply returns 64 octets
		745	$handle->push_write ("request 2\015\012");
		746
		747	# simply read 64 bytes, always
		748	$handle->push_read (chunk => 64, sub {
		749	my $response = $_[1];
		750	...
		751	});
		752
		753	=over 4
		754
		755	=cut
		756
		757	sub _drain_rbuf {
		758	my ($self) = @_;
		759
		760	local $self->{_in_drain} = 1;
		761
		762	if (
		763	defined $self->{rbuf_max}
		764	&& $self->{rbuf_max} < length $self->{rbuf}
		765	) {
		766	$self->_error (&Errno::ENOSPC, 1), return;
		767	}
		768
		769	while () {
		770	my $len = length $self->{rbuf};
		771
		772	if (my $cb = shift @{ $self->{_queue} }) {
		773	unless ($cb->($self)) {
		774	if ($self->{_eof}) {
		775	# no progress can be made (not enough data and no data forthcoming)
		776	$self->_error (&Errno::EPIPE, 1), return;
54	}	777	}
		778
		779	unshift @{ $self->{_queue} }, $cb;
		780	last;
55	}	781	}
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}) {	782	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	783	last unless $len;
122		784
		785	$self->{on_read}($self);
		786
		787	if (
		788	$len == length $self->{rbuf} # if no data has been consumed
		789	&& !@{ $self->{_queue} } # and the queue is still empty
		790	&& $self->{on_read} # but we still have on_read
		791	) {
		792	# no further data will arrive
		793	# so no progress can be made
		794	$self->_error (&Errno::EPIPE, 1), return
		795	if $self->{_eof};
		796
		797	last; # more data might arrive
		798	}
		799	} else {
		800	# read side becomes idle
		801	delete $self->{_rw} unless $self->{tls};
		802	last;
		803	}
		804	}
		805
123	} elsif ($self->{on_eof}) {	806	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	807	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	808	$self->{on_eof}($self)
		809	} else {
		810	$self->_error (0, 1);
		811	}
128	}	812	}
129		813
130	return $self	814	# may need to restart read watcher
		815	unless ($self->{_rw}) {
		816	$self->start_read
		817	if $self->{on_read} || @{ $self->{_queue} };
		818	}
131	}	819	}
132		820
133	=item B<fh>	821	=item $handle->on_read ($cb)
134		822
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	823	This replaces the currently set C<on_read> callback, or clears it (when
136		824	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	825	constructor.
138
139	sub fh { $_[0]->{fh} }
140
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		826
149	=cut	827	=cut
150		828
151	sub on_read {	829	sub on_read {
152	my ($self, $cb) = @_;	830	my ($self, $cb) = @_;
		831
153	$self->{on_read} = $cb;	832	$self->{on_read} = $cb;
		833	$self->_drain_rbuf if $cb && !$self->{_in_drain};
		834	}
154		835
155	unless (defined $self->{on_read}) {	836	=item $handle->rbuf
156	delete $self->{on_read_w};	837
		838	Returns the read buffer (as a modifiable lvalue).
		839
		840	You can access the read buffer directly as the C<< ->{rbuf} >> member, if
		841	you want.
		842
		843	NOTE: The read buffer should only be used or modified if the C<on_read>,
		844	C<push_read> or C<unshift_read> methods are used. The other read methods
		845	automatically manage the read buffer.
		846
		847	=cut
		848
		849	sub rbuf : lvalue {
		850	$_[0]{rbuf}
		851	}
		852
		853	=item $handle->push_read ($cb)
		854
		855	=item $handle->unshift_read ($cb)
		856
		857	Append the given callback to the end of the queue (C<push_read>) or
		858	prepend it (C<unshift_read>).
		859
		860	The callback is called each time some additional read data arrives.
		861
		862	It must check whether enough data is in the read buffer already.
		863
		864	If not enough data is available, it must return the empty list or a false
		865	value, in which case it will be called repeatedly until enough data is
		866	available (or an error condition is detected).
		867
		868	If enough data was available, then the callback must remove all data it is
		869	interested in (which can be none at all) and return a true value. After returning
		870	true, it will be removed from the queue.
		871
		872	=cut
		873
		874	our %RH;
		875
		876	sub register_read_type($$) {
		877	$RH{$_[0]} = $_[1];
		878	}
		879
		880	sub push_read {
		881	my $self = shift;
		882	my $cb = pop;
		883
		884	if (@_) {
		885	my $type = shift;
		886
		887	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		888	->($self, $cb, @_);
		889	}
		890
		891	push @{ $self->{_queue} }, $cb;
		892	$self->_drain_rbuf unless $self->{_in_drain};
		893	}
		894
		895	sub unshift_read {
		896	my $self = shift;
		897	my $cb = pop;
		898
		899	if (@_) {
		900	my $type = shift;
		901
		902	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		903	->($self, $cb, @_);
		904	}
		905
		906
		907	unshift @{ $self->{_queue} }, $cb;
		908	$self->_drain_rbuf unless $self->{_in_drain};
		909	}
		910
		911	=item $handle->push_read (type => @args, $cb)
		912
		913	=item $handle->unshift_read (type => @args, $cb)
		914
		915	Instead of providing a callback that parses the data itself you can chose
		916	between a number of predefined parsing formats, for chunks of data, lines
		917	etc.
		918
		919	Predefined types are (if you have ideas for additional types, feel free to
		920	drop by and tell us):
		921
		922	=over 4
		923
		924	=item chunk => $octets, $cb->($handle, $data)
		925
		926	Invoke the callback only once C<$octets> bytes have been read. Pass the
		927	data read to the callback. The callback will never be called with less
		928	data.
		929
		930	Example: read 2 bytes.
		931
		932	$handle->push_read (chunk => 2, sub {
		933	warn "yay ", unpack "H*", $_[1];
		934	});
		935
		936	=cut
		937
		938	register_read_type chunk => sub {
		939	my ($self, $cb, $len) = @_;
		940
		941	sub {
		942	$len <= length $_[0]{rbuf} or return;
		943	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		944	1
		945	}
		946	};
		947
		948	=item line => [$eol, ]$cb->($handle, $line, $eol)
		949
		950	The callback will be called only once a full line (including the end of
		951	line marker, C<$eol>) has been read. This line (excluding the end of line
		952	marker) will be passed to the callback as second argument (C<$line>), and
		953	the end of line marker as the third argument (C<$eol>).
		954
		955	The end of line marker, C<$eol>, can be either a string, in which case it
		956	will be interpreted as a fixed record end marker, or it can be a regex
		957	object (e.g. created by C<qr>), in which case it is interpreted as a
		958	regular expression.
		959
		960	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		961	undef), then C<qr|\015?\012|> is used (which is good for most internet
		962	protocols).
		963
		964	Partial lines at the end of the stream will never be returned, as they are
		965	not marked by the end of line marker.
		966
		967	=cut
		968
		969	register_read_type line => sub {
		970	my ($self, $cb, $eol) = @_;
		971
		972	if (@_ < 3) {
		973	# this is more than twice as fast as the generic code below
		974	sub {
		975	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		976
		977	$cb->($_[0], $1, $2);
		978	1
		979	}
		980	} else {
		981	$eol = quotemeta $eol unless ref $eol;
		982	$eol = qr|^(.*?)($eol)|s;
		983
		984	sub {
		985	$_[0]{rbuf} =~ s/$eol// or return;
		986
		987	$cb->($_[0], $1, $2);
		988	1
		989	}
		990	}
		991	};
		992
		993	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		994
		995	Makes a regex match against the regex object C<$accept> and returns
		996	everything up to and including the match.
		997
		998	Example: read a single line terminated by '\n'.
		999
		1000	$handle->push_read (regex => qr<\n>, sub { ... });
		1001
		1002	If C<$reject> is given and not undef, then it determines when the data is
		1003	to be rejected: it is matched against the data when the C<$accept> regex
		1004	does not match and generates an C<EBADMSG> error when it matches. This is
		1005	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1006	receive buffer overflow).
		1007
		1008	Example: expect a single decimal number followed by whitespace, reject
		1009	anything else (not the use of an anchor).
		1010
		1011	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1012
		1013	If C<$skip> is given and not C<undef>, then it will be matched against
		1014	the receive buffer when neither C<$accept> nor C<$reject> match,
		1015	and everything preceding and including the match will be accepted
		1016	unconditionally. This is useful to skip large amounts of data that you
		1017	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1018	have to start matching from the beginning. This is purely an optimisation
		1019	and is usually worth only when you expect more than a few kilobytes.
		1020
		1021	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1022	expect the header to be very large (it isn't in practise, but...), we use
		1023	a skip regex to skip initial portions. The skip regex is tricky in that
		1024	it only accepts something not ending in either \015 or \012, as these are
		1025	required for the accept regex.
		1026
		1027	$handle->push_read (regex =>
		1028	qr<\015\012\015\012>,
		1029	undef, # no reject
		1030	qr<^.*[^\015\012]>,
		1031	sub { ... });
		1032
		1033	=cut
		1034
		1035	register_read_type regex => sub {
		1036	my ($self, $cb, $accept, $reject, $skip) = @_;
		1037
		1038	my $data;
		1039	my $rbuf = \$self->{rbuf};
		1040
		1041	sub {
		1042	# accept
		1043	if ($$rbuf =~ $accept) {
		1044	$data .= substr $$rbuf, 0, $+[0], "";
		1045	$cb->($self, $data);
157	return;	1046	return 1;
		1047	}
		1048
		1049	# reject
		1050	if ($reject && $$rbuf =~ $reject) {
		1051	$self->_error (&Errno::EBADMSG);
		1052	}
		1053
		1054	# skip
		1055	if ($skip && $$rbuf =~ $skip) {
		1056	$data .= substr $$rbuf, 0, $+[0], "";
		1057	}
		1058
		1059	()
158	}	1060	}
159		1061	};
160	$self->{on_read_w} =	1062
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1063	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1064
163	my $rbuf_len = length $self->{rbuf};	1065	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1066
165	if (defined $self->{read_size}) {	1067	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1068
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1069	=cut
168	} else {	1070
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1071	register_read_type netstring => sub {
		1072	my ($self, $cb) = @_;
		1073
		1074	sub {
		1075	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1076	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1077	$self->_error (&Errno::EBADMSG);
170	}	1078	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1079	return;
		1080	}
172		1081
173	if (not defined $l) {	1082	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1083
178	} elsif ($l == 0) {	1084	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1085	my $string = $_[1];
180	delete $self->{on_read_w};	1086	$_[0]->unshift_read (chunk => 1, sub {
181		1087	if ($_[1] eq ",") {
		1088	$cb->($_[0], $string);
182	} else {	1089	} else {
183	$self->{on_read}->($self);	1090	$self->_error (&Errno::EBADMSG);
		1091	}
		1092	});
		1093	});
		1094
		1095	1
		1096	}
		1097	};
		1098
		1099	=item packstring => $format, $cb->($handle, $string)
		1100
		1101	An octet string prefixed with an encoded length. The encoding C<$format>
		1102	uses the same format as a Perl C<pack> format, but must specify a single
		1103	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1104	optional C<!>, C<< < >> or C<< > >> modifier).
		1105
		1106	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1107	EPP uses a prefix of C<N> (4 octtes).
		1108
		1109	Example: read a block of data prefixed by its length in BER-encoded
		1110	format (very efficient).
		1111
		1112	$handle->push_read (packstring => "w", sub {
		1113	my ($handle, $data) = @_;
		1114	});
		1115
		1116	=cut
		1117
		1118	register_read_type packstring => sub {
		1119	my ($self, $cb, $format) = @_;
		1120
		1121	sub {
		1122	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1123	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1124	or return;
		1125
		1126	$format = length pack $format, $len;
		1127
		1128	# bypass unshift if we already have the remaining chunk
		1129	if ($format + $len <= length $_[0]{rbuf}) {
		1130	my $data = substr $_[0]{rbuf}, $format, $len;
		1131	substr $_[0]{rbuf}, 0, $format + $len, "";
		1132	$cb->($_[0], $data);
		1133	} else {
		1134	# remove prefix
		1135	substr $_[0]{rbuf}, 0, $format, "";
		1136
		1137	# read remaining chunk
		1138	$_[0]->unshift_read (chunk => $len, $cb);
		1139	}
		1140
		1141	1
		1142	}
		1143	};
		1144
		1145	=item json => $cb->($handle, $hash_or_arrayref)
		1146
		1147	Reads a JSON object or array, decodes it and passes it to the callback.
		1148
		1149	If a C<json> object was passed to the constructor, then that will be used
		1150	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1151
		1152	This read type uses the incremental parser available with JSON version
		1153	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1154	dependency on your own: this module will load the JSON module, but
		1155	AnyEvent does not depend on it itself.
		1156
		1157	Since JSON texts are fully self-delimiting, the C<json> read and write
		1158	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1159	the C<json> write type description, above, for an actual example.
		1160
		1161	=cut
		1162
		1163	register_read_type json => sub {
		1164	my ($self, $cb) = @_;
		1165
		1166	require JSON;
		1167
		1168	my $data;
		1169	my $rbuf = \$self->{rbuf};
		1170
		1171	my $json = $self->{json} ||= JSON->new->utf8;
		1172
		1173	sub {
		1174	my $ref = $json->incr_parse ($self->{rbuf});
		1175
		1176	if ($ref) {
		1177	$self->{rbuf} = $json->incr_text;
		1178	$json->incr_text = "";
		1179	$cb->($self, $ref);
		1180
		1181	1
		1182	} else {
		1183	$self->{rbuf} = "";
		1184	()
		1185	}
		1186	}
		1187	};
		1188
		1189	=item storable => $cb->($handle, $ref)
		1190
		1191	Deserialises a L<Storable> frozen representation as written by the
		1192	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1193	data).
		1194
		1195	Raises C<EBADMSG> error if the data could not be decoded.
		1196
		1197	=cut
		1198
		1199	register_read_type storable => sub {
		1200	my ($self, $cb) = @_;
		1201
		1202	require Storable;
		1203
		1204	sub {
		1205	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1206	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1207	or return;
		1208
		1209	my $format = length pack "w", $len;
		1210
		1211	# bypass unshift if we already have the remaining chunk
		1212	if ($format + $len <= length $_[0]{rbuf}) {
		1213	my $data = substr $_[0]{rbuf}, $format, $len;
		1214	substr $_[0]{rbuf}, 0, $format + $len, "";
		1215	$cb->($_[0], Storable::thaw ($data));
		1216	} else {
		1217	# remove prefix
		1218	substr $_[0]{rbuf}, 0, $format, "";
		1219
		1220	# read remaining chunk
		1221	$_[0]->unshift_read (chunk => $len, sub {
		1222	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1223	$cb->($_[0], $ref);
		1224	} else {
		1225	$self->_error (&Errno::EBADMSG);
		1226	}
		1227	});
		1228	}
		1229
		1230	1
		1231	}
		1232	};
		1233
		1234	=back
		1235
		1236	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1237
		1238	This function (not method) lets you add your own types to C<push_read>.
		1239
		1240	Whenever the given C<type> is used, C<push_read> will invoke the code
		1241	reference with the handle object, the callback and the remaining
		1242	arguments.
		1243
		1244	The code reference is supposed to return a callback (usually a closure)
		1245	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1246
		1247	It should invoke the passed callback when it is done reading (remember to
		1248	pass C<$handle> as first argument as all other callbacks do that).
		1249
		1250	Note that this is a function, and all types registered this way will be
		1251	global, so try to use unique names.
		1252
		1253	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1254	search for C<register_read_type>)).
		1255
		1256	=item $handle->stop_read
		1257
		1258	=item $handle->start_read
		1259
		1260	In rare cases you actually do not want to read anything from the
		1261	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1262	any queued callbacks will be executed then. To start reading again, call
		1263	C<start_read>.
		1264
		1265	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1266	you change the C<on_read> callback or push/unshift a read callback, and it
		1267	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1268	there are any read requests in the queue.
		1269
		1270	These methods will have no effect when in TLS mode (as TLS doesn't support
		1271	half-duplex connections).
		1272
		1273	=cut
		1274
		1275	sub stop_read {
		1276	my ($self) = @_;
		1277
		1278	delete $self->{_rw} unless $self->{tls};
		1279	}
		1280
		1281	sub start_read {
		1282	my ($self) = @_;
		1283
		1284	unless ($self->{_rw} || $self->{_eof}) {
		1285	Scalar::Util::weaken $self;
		1286
		1287	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1288	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1289	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1290
		1291	if ($len > 0) {
		1292	$self->{_activity} = AnyEvent->now;
		1293
		1294	if ($self->{tls}) {
		1295	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1296	&_dotls ($self);
		1297	} else {
		1298	$self->_drain_rbuf unless $self->{_in_drain};
		1299	}
		1300
		1301	} elsif (defined $len) {
		1302	delete $self->{_rw};
		1303	$self->{_eof} = 1;
		1304	$self->_drain_rbuf unless $self->{_in_drain};
		1305
		1306	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1307	return $self->_error ($!, 1);
184	}	1308	}
185	});	1309	});
		1310	}
186	}	1311	}
187		1312
188	=item B<on_error ($callback)>	1313	sub _dotls {
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) = @_;	1314	my ($self) = @_;
240		1315
241	$self->{read_cb} = $cb;	1316	my $buf;
242	my $old_blk_size = $self->{read_block_size};
243	$self->{read_block_size} = $len;
244		1317
245	$self->on_read (sub {	1318	if (length $self->{_tls_wbuf}) {
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";	1319	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
247		1320	substr $self->{_tls_wbuf}, 0, $len, "";
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	}	1321	}
253	});	1322	}
254	}
255		1323
256	=item B<readlines ($callback)>	1324	while (defined ($buf = Net::SSLeay::read ($self->{tls}))) {
257		1325	unless (length $buf) {
258	=item B<readlines ($sep, $callback)>	1326	# let's treat SSL-eof as we treat normal EOF
259		1327	delete $self->{_rw};
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1328	$self->{_eof} = 1;
261	if C<$sep> is not provided. C<$sep> will be used as "line" seperator.	1329	&_freetls;
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	}	1330	}
293	$self->{on_readline}->($_[0], @lines);	1331
		1332	$self->{rbuf} .= $buf;
		1333	$self->_drain_rbuf unless $self->{_in_drain};
		1334	$self->{tls} or return; # tls session might have gone away in callback
294	});	1335	}
295	}
296		1336
297	=item B<write ($data)>	1337	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
298		1338
299	=item B<write ($callback)>	1339	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
		1340	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
		1341	return $self->_error ($!, 1);
		1342	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
		1343	return $self->_error (&Errno::EIO, 1);
		1344	}
300		1345
301	=item B<write ($data, $callback)>	1346	# all others are fine for our purposes
		1347	}
302		1348
303	This method will write C<$data> to the filehandle and call the C<$callback>	1349	while (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {
304	afterwards. If only C<$callback> is provided it will be called when the	1350	$self->{wbuf} .= $buf;
305	write buffer becomes empty the next time (or immediately if it already is empty).	1351	$self->_drain_wbuf;
		1352	}
		1353	}
306		1354
307	=cut	1355	=item $handle->starttls ($tls[, $tls_ctx])
308		1356
309	sub write {	1357	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1358	object is created, you can also do that at a later time by calling
		1359	C<starttls>.
		1360
		1361	The first argument is the same as the C<tls> constructor argument (either
		1362	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1363
		1364	The second argument is the optional C<Net::SSLeay::CTX> object that is
		1365	used when AnyEvent::Handle has to create its own TLS connection object.
		1366
		1367	The TLS connection object will end up in C<< $handle->{tls} >> after this
		1368	call and can be used or changed to your liking. Note that the handshake
		1369	might have already started when this function returns.
		1370
		1371	If it an error to start a TLS handshake more than once per
		1372	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1373
		1374	=cut
		1375
		1376	sub starttls {
310	my ($self, $data, $cb) = @_;	1377	my ($self, $ssl, $ctx) = @_;
311	if (ref $data) { $cb = $data; undef $data }
312	push @{$self->{write_bufs}}, [$data, $cb];
313	$self->_check_writer;
314	}
315		1378
316	sub _check_writer {	1379	require Net::SSLeay;
		1380
		1381	Carp::croak "it is an error to call starttls more than once on an Anyevent::Handle object"
		1382	if $self->{tls};
		1383
		1384	if ($ssl eq "accept") {
		1385	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
		1386	Net::SSLeay::set_accept_state ($ssl);
		1387	} elsif ($ssl eq "connect") {
		1388	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
		1389	Net::SSLeay::set_connect_state ($ssl);
		1390	}
		1391
		1392	$self->{tls} = $ssl;
		1393
		1394	# basically, this is deep magic (because SSL_read should have the same issues)
		1395	# but the openssl maintainers basically said: "trust us, it just works".
		1396	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1397	# and mismaintained ssleay-module doesn't even offer them).
		1398	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1399	#
		1400	# in short: this is a mess.
		1401	#
		1402	# note that we do not try to keep the length constant between writes as we are required to do.
		1403	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1404	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1405	# have identity issues in that area.
		1406	Net::SSLeay::CTX_set_mode ($self->{tls},
		1407	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1408	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1409
		1410	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1411	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1412
		1413	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
		1414
		1415	&_dotls; # need to trigger the initial handshake
		1416	$self->start_read; # make sure we actually do read
		1417	}
		1418
		1419	=item $handle->stoptls
		1420
		1421	Shuts down the SSL connection - this makes a proper EOF handshake by
		1422	sending a close notify to the other side, but since OpenSSL doesn't
		1423	support non-blocking shut downs, it is not possible to re-use the stream
		1424	afterwards.
		1425
		1426	=cut
		1427
		1428	sub stoptls {
317	my ($self) = @_;	1429	my ($self) = @_;
318		1430
319	if ($self->{write_w}) {	1431	if ($self->{tls}) {
320	unless ($self->{write_cb}) {	1432	Net::SSLeay::shutdown ($self->{tls});
321	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {	1433
322	my $wba = shift @{$self->{write_bufs}};	1434	&_dotls;
323	$self->{wbuf} .= $wba->[0];	1435
324	}	1436	# we don't give a shit. no, we do, but we can't. no...
325	}	1437	# we, we... have to use openssl :/
326	return;	1438	&_freetls;
		1439	}
		1440	}
		1441
		1442	sub _freetls {
		1443	my ($self) = @_;
		1444
		1445	return unless $self->{tls};
		1446
		1447	Net::SSLeay::free (delete $self->{tls});
327	}	1448
		1449	delete @$self{qw(_rbio _wbio _tls_wbuf)};
		1450	}
328		1451
329	my $wba = shift @{$self->{write_bufs}}	1452	sub DESTROY {
330	or return;	1453	my $self = shift;
331		1454
332	unless (defined $wba->[0]) {	1455	&_freetls;
333	$wba->[1]->($self) if $wba->[1];
334	$self->_check_writer;
335	return;
336	}
337		1456
338	$self->{wbuf} = $wba->[0];	1457	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
339	$self->{write_cb} = $wba->[1];
340		1458
341	$self->{write_w} =	1459	if ($linger && length $self->{wbuf}) {
342	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1460	my $fh = delete $self->{fh};
		1461	my $wbuf = delete $self->{wbuf};
		1462
		1463	my @linger;
		1464
		1465	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
343	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1466	my $len = syswrite $fh, $wbuf, length $wbuf;
344		1467
345	if (not defined $l) {	1468	if ($len > 0) {
346	return if $! == EAGAIN || $! == EINTR;	1469	substr $wbuf, 0, $len, "";
347	delete $self->{write_w};
348	$self->{on_error}->($self) if $self->{on_error};
349
350	} else {	1470	} else {
351	substr $self->{wbuf}, 0, $l, '';	1471	@linger = (); # end
352
353	if (length ($self->{wbuf}) == 0) {
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	}	1472	}
363	});	1473	});
		1474	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1475	@linger = ();
		1476	});
		1477	}
		1478	}
		1479
		1480	=item AnyEvent::Handle::TLS_CTX
		1481
		1482	This function creates and returns the Net::SSLeay::CTX object used by
		1483	default for TLS mode.
		1484
		1485	The context is created like this:
		1486
		1487	Net::SSLeay::load_error_strings;
		1488	Net::SSLeay::SSLeay_add_ssl_algorithms;
		1489	Net::SSLeay::randomize;
		1490
		1491	my $CTX = Net::SSLeay::CTX_new;
		1492
		1493	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
		1494
		1495	=cut
		1496
		1497	our $TLS_CTX;
		1498
		1499	sub TLS_CTX() {
		1500	$TLS_CTX || do {
		1501	require Net::SSLeay;
		1502
		1503	Net::SSLeay::load_error_strings ();
		1504	Net::SSLeay::SSLeay_add_ssl_algorithms ();
		1505	Net::SSLeay::randomize ();
		1506
		1507	$TLS_CTX = Net::SSLeay::CTX_new ();
		1508
		1509	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
		1510
		1511	$TLS_CTX
		1512	}
364	}	1513	}
365		1514
366	=back	1515	=back
367		1516
		1517
		1518	=head1 NONFREQUENTLY ASKED QUESTIONS
		1519
		1520	=over 4
		1521
		1522	=item How do I read data until the other side closes the connection?
		1523
		1524	If you just want to read your data into a perl scalar, the easiest way
		1525	to achieve this is by setting an C<on_read> callback that does nothing,
		1526	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1527	will be in C<$_[0]{rbuf}>:
		1528
		1529	$handle->on_read (sub { });
		1530	$handle->on_eof (undef);
		1531	$handle->on_error (sub {
		1532	my $data = delete $_[0]{rbuf};
		1533	undef $handle;
		1534	});
		1535
		1536	The reason to use C<on_error> is that TCP connections, due to latencies
		1537	and packets loss, might get closed quite violently with an error, when in
		1538	fact, all data has been received.
		1539
		1540	It is usually better to use acknowledgements when transfering data,
		1541	to make sure the other side hasn't just died and you got the data
		1542	intact. This is also one reason why so many internet protocols have an
		1543	explicit QUIT command.
		1544
		1545
		1546	=item I don't want to destroy the handle too early - how do I wait until
		1547	all data has been written?
		1548
		1549	After writing your last bits of data, set the C<on_drain> callback
		1550	and destroy the handle in there - with the default setting of
		1551	C<low_water_mark> this will be called precisely when all data has been
		1552	written to the socket:
		1553
		1554	$handle->push_write (...);
		1555	$handle->on_drain (sub {
		1556	warn "all data submitted to the kernel\n";
		1557	undef $handle;
		1558	});
		1559
		1560	=back
		1561
		1562
		1563	=head1 SUBCLASSING AnyEvent::Handle
		1564
		1565	In many cases, you might want to subclass AnyEvent::Handle.
		1566
		1567	To make this easier, a given version of AnyEvent::Handle uses these
		1568	conventions:
		1569
		1570	=over 4
		1571
		1572	=item * all constructor arguments become object members.
		1573
		1574	At least initially, when you pass a C<tls>-argument to the constructor it
		1575	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1576	mutated later on (for example C<tls> will hold the TLS connection object).
		1577
		1578	=item * other object member names are prefixed with an C<_>.
		1579
		1580	All object members not explicitly documented (internal use) are prefixed
		1581	with an underscore character, so the remaining non-C<_>-namespace is free
		1582	for use for subclasses.
		1583
		1584	=item * all members not documented here and not prefixed with an underscore
		1585	are free to use in subclasses.
		1586
		1587	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1588	member variables, but thats just life, at least it is documented.
		1589
		1590	=back
		1591
368	=head1 AUTHOR	1592	=head1 AUTHOR
369		1593
370	Robin Redeker, C<< <elmex at ta-sa.org> >>	1594	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
371		1595
372	=cut	1596	=cut
373		1597
374	1; # End of AnyEvent::Handle	1598	1; # End of AnyEvent::Handle

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