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Revision 1.61 by root, Fri Jun 6 10:23:50 2008 UTC vs.
Revision 1.100 by root, Thu Oct 23 02:44:50 2008 UTC

1package AnyEvent::Handle; 1package AnyEvent::Handle;
2 2
3no warnings; 3no warnings;
4use strict; 4use strict qw(subs vars);
5 5
6use AnyEvent (); 6use AnyEvent ();
7use AnyEvent::Util qw(WSAEWOULDBLOCK); 7use AnyEvent::Util qw(WSAEWOULDBLOCK);
8use Scalar::Util (); 8use Scalar::Util ();
9use Carp (); 9use Carp ();
14 14
15AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent 15AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
16 16
17=cut 17=cut
18 18
19our $VERSION = 4.14; 19our $VERSION = 4.3;
20 20
21=head1 SYNOPSIS 21=head1 SYNOPSIS
22 22
23 use AnyEvent; 23 use AnyEvent;
24 use AnyEvent::Handle; 24 use AnyEvent::Handle;
49 49
50This module is a helper module to make it easier to do event-based I/O on 50This module is a helper module to make it easier to do event-based I/O on
51filehandles. For utility functions for doing non-blocking connects and accepts 51filehandles. For utility functions for doing non-blocking connects and accepts
52on sockets see L<AnyEvent::Util>. 52on sockets see L<AnyEvent::Util>.
53 53
54The L<AnyEvent::Intro> tutorial contains some well-documented
55AnyEvent::Handle examples.
56
54In the following, when the documentation refers to of "bytes" then this 57In the following, when the documentation refers to of "bytes" then this
55means characters. As sysread and syswrite are used for all I/O, their 58means characters. As sysread and syswrite are used for all I/O, their
56treatment of characters applies to this module as well. 59treatment of characters applies to this module as well.
57 60
58All callbacks will be invoked with the handle object as their first 61All callbacks will be invoked with the handle object as their first
70 73
71=item fh => $filehandle [MANDATORY] 74=item fh => $filehandle [MANDATORY]
72 75
73The filehandle this L<AnyEvent::Handle> object will operate on. 76The filehandle this L<AnyEvent::Handle> object will operate on.
74 77
75NOTE: The filehandle will be set to non-blocking (using 78NOTE: The filehandle will be set to non-blocking mode (using
76AnyEvent::Util::fh_nonblocking). 79C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
80that mode.
77 81
78=item on_eof => $cb->($handle) 82=item on_eof => $cb->($handle)
79 83
80Set the callback to be called when an end-of-file condition is detcted, 84Set the callback to be called when an end-of-file condition is detected,
81i.e. in the case of a socket, when the other side has closed the 85i.e. in the case of a socket, when the other side has closed the
82connection cleanly. 86connection cleanly.
83 87
88For sockets, this just means that the other side has stopped sending data,
89you can still try to write data, and, in fact, one can return from the eof
90callback and continue writing data, as only the read part has been shut
91down.
92
84While not mandatory, it is highly recommended to set an eof callback, 93While not mandatory, it is I<highly> recommended to set an eof callback,
85otherwise you might end up with a closed socket while you are still 94otherwise you might end up with a closed socket while you are still
86waiting for data. 95waiting for data.
96
97If an EOF condition has been detected but no C<on_eof> callback has been
98set, then a fatal error will be raised with C<$!> set to <0>.
87 99
88=item on_error => $cb->($handle, $fatal) 100=item on_error => $cb->($handle, $fatal)
89 101
90This is the error callback, which is called when, well, some error 102This is the error callback, which is called when, well, some error
91occured, such as not being able to resolve the hostname, failure to 103occured, such as not being able to resolve the hostname, failure to
92connect or a read error. 104connect or a read error.
93 105
94Some errors are fatal (which is indicated by C<$fatal> being true). On 106Some errors are fatal (which is indicated by C<$fatal> being true). On
95fatal errors the handle object will be shut down and will not be 107fatal errors the handle object will be shut down and will not be usable
108(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
109errors are an EOF condition with active (but unsatisifable) read watchers
110(C<EPIPE>) or I/O errors.
111
96usable. Non-fatal errors can be retried by simply returning, but it is 112Non-fatal errors can be retried by simply returning, but it is recommended
97recommended to simply ignore this parameter and instead abondon the handle 113to simply ignore this parameter and instead abondon the handle object
98object when this callback is invoked. 114when this callback is invoked. Examples of non-fatal errors are timeouts
115C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
99 116
100On callback entrance, the value of C<$!> contains the operating system 117On callback entrance, the value of C<$!> contains the operating system
101error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>). 118error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
102 119
103While not mandatory, it is I<highly> recommended to set this callback, as 120While not mandatory, it is I<highly> recommended to set this callback, as
124This sets the callback that is called when the write buffer becomes empty 141This sets the callback that is called when the write buffer becomes empty
125(or when the callback is set and the buffer is empty already). 142(or when the callback is set and the buffer is empty already).
126 143
127To append to the write buffer, use the C<< ->push_write >> method. 144To append to the write buffer, use the C<< ->push_write >> method.
128 145
146This callback is useful when you don't want to put all of your write data
147into the queue at once, for example, when you want to write the contents
148of some file to the socket you might not want to read the whole file into
149memory and push it into the queue, but instead only read more data from
150the file when the write queue becomes empty.
151
129=item timeout => $fractional_seconds 152=item timeout => $fractional_seconds
130 153
131If non-zero, then this enables an "inactivity" timeout: whenever this many 154If non-zero, then this enables an "inactivity" timeout: whenever this many
132seconds pass without a successful read or write on the underlying file 155seconds pass without a successful read or write on the underlying file
133handle, the C<on_timeout> callback will be invoked (and if that one is 156handle, the C<on_timeout> callback will be invoked (and if that one is
134missing, an C<ETIMEDOUT> error will be raised). 157missing, a non-fatal C<ETIMEDOUT> error will be raised).
135 158
136Note that timeout processing is also active when you currently do not have 159Note that timeout processing is also active when you currently do not have
137any outstanding read or write requests: If you plan to keep the connection 160any outstanding read or write requests: If you plan to keep the connection
138idle then you should disable the timout temporarily or ignore the timeout 161idle then you should disable the timout temporarily or ignore the timeout
139in the C<on_timeout> callback. 162in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
163restart the timeout.
140 164
141Zero (the default) disables this timeout. 165Zero (the default) disables this timeout.
142 166
143=item on_timeout => $cb->($handle) 167=item on_timeout => $cb->($handle)
144 168
148 172
149=item rbuf_max => <bytes> 173=item rbuf_max => <bytes>
150 174
151If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>) 175If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
152when the read buffer ever (strictly) exceeds this size. This is useful to 176when the read buffer ever (strictly) exceeds this size. This is useful to
153avoid denial-of-service attacks. 177avoid some forms of denial-of-service attacks.
154 178
155For example, a server accepting connections from untrusted sources should 179For example, a server accepting connections from untrusted sources should
156be configured to accept only so-and-so much data that it cannot act on 180be configured to accept only so-and-so much data that it cannot act on
157(for example, when expecting a line, an attacker could send an unlimited 181(for example, when expecting a line, an attacker could send an unlimited
158amount of data without a callback ever being called as long as the line 182amount of data without a callback ever being called as long as the line
159isn't finished). 183isn't finished).
160 184
185=item autocork => <boolean>
186
187When disabled (the default), then C<push_write> will try to immediately
188write the data to the handle, if possible. This avoids having to register
189a write watcher and wait for the next event loop iteration, but can
190be inefficient if you write multiple small chunks (on the wire, this
191disadvantage is usually avoided by your kernel's nagle algorithm, see
192C<no_delay>, but this option can save costly syscalls).
193
194When enabled, then writes will always be queued till the next event loop
195iteration. This is efficient when you do many small writes per iteration,
196but less efficient when you do a single write only per iteration (or when
197the write buffer often is full). It also increases write latency.
198
199=item no_delay => <boolean>
200
201When doing small writes on sockets, your operating system kernel might
202wait a bit for more data before actually sending it out. This is called
203the Nagle algorithm, and usually it is beneficial.
204
205In some situations you want as low a delay as possible, which can be
206accomplishd by setting this option to a true value.
207
208The default is your opertaing system's default behaviour (most likely
209enabled), this option explicitly enables or disables it, if possible.
210
161=item read_size => <bytes> 211=item read_size => <bytes>
162 212
163The default read block size (the amount of bytes this module will try to read 213The default read block size (the amount of bytes this module will
164during each (loop iteration). Default: C<8192>. 214try to read during each loop iteration, which affects memory
215requirements). Default: C<8192>.
165 216
166=item low_water_mark => <bytes> 217=item low_water_mark => <bytes>
167 218
168Sets the amount of bytes (default: C<0>) that make up an "empty" write 219Sets the amount of bytes (default: C<0>) that make up an "empty" write
169buffer: If the write reaches this size or gets even samller it is 220buffer: If the write reaches this size or gets even samller it is
170considered empty. 221considered empty.
171 222
223Sometimes it can be beneficial (for performance reasons) to add data to
224the write buffer before it is fully drained, but this is a rare case, as
225the operating system kernel usually buffers data as well, so the default
226is good in almost all cases.
227
228=item linger => <seconds>
229
230If non-zero (default: C<3600>), then the destructor of the
231AnyEvent::Handle object will check whether there is still outstanding
232write data and will install a watcher that will write this data to the
233socket. No errors will be reported (this mostly matches how the operating
234system treats outstanding data at socket close time).
235
236This will not work for partial TLS data that could not be encoded
237yet. This data will be lost. Calling the C<stoptls> method in time might
238help.
239
172=item tls => "accept" | "connect" | Net::SSLeay::SSL object 240=item tls => "accept" | "connect" | Net::SSLeay::SSL object
173 241
174When this parameter is given, it enables TLS (SSL) mode, that means it 242When this parameter is given, it enables TLS (SSL) mode, that means
175will start making tls handshake and will transparently encrypt/decrypt 243AnyEvent will start a TLS handshake as soon as the conenction has been
176data. 244established and will transparently encrypt/decrypt data afterwards.
177 245
178TLS mode requires Net::SSLeay to be installed (it will be loaded 246TLS mode requires Net::SSLeay to be installed (it will be loaded
179automatically when you try to create a TLS handle). 247automatically when you try to create a TLS handle): this module doesn't
248have a dependency on that module, so if your module requires it, you have
249to add the dependency yourself.
180 250
181For the TLS server side, use C<accept>, and for the TLS client side of a 251Unlike TCP, TLS has a server and client side: for the TLS server side, use
182connection, use C<connect> mode. 252C<accept>, and for the TLS client side of a connection, use C<connect>
253mode.
183 254
184You can also provide your own TLS connection object, but you have 255You can also provide your own TLS connection object, but you have
185to make sure that you call either C<Net::SSLeay::set_connect_state> 256to make sure that you call either C<Net::SSLeay::set_connect_state>
186or C<Net::SSLeay::set_accept_state> on it before you pass it to 257or C<Net::SSLeay::set_accept_state> on it before you pass it to
187AnyEvent::Handle. 258AnyEvent::Handle.
188 259
189See the C<starttls> method if you need to start TLs negotiation later. 260See the C<< ->starttls >> method for when need to start TLS negotiation later.
190 261
191=item tls_ctx => $ssl_ctx 262=item tls_ctx => $ssl_ctx
192 263
193Use the given Net::SSLeay::CTX object to create the new TLS connection 264Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
194(unless a connection object was specified directly). If this parameter is 265(unless a connection object was specified directly). If this parameter is
195missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>. 266missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
196 267
197=item json => JSON or JSON::XS object 268=item json => JSON or JSON::XS object
198 269
199This is the json coder object used by the C<json> read and write types. 270This is the json coder object used by the C<json> read and write types.
200 271
201If you don't supply it, then AnyEvent::Handle will create and use a 272If you don't supply it, then AnyEvent::Handle will create and use a
202suitable one, which will write and expect UTF-8 encoded JSON texts. 273suitable one (on demand), which will write and expect UTF-8 encoded JSON
274texts.
203 275
204Note that you are responsible to depend on the JSON module if you want to 276Note that you are responsible to depend on the JSON module if you want to
205use this functionality, as AnyEvent does not have a dependency itself. 277use this functionality, as AnyEvent does not have a dependency itself.
206 278
207=item filter_r => $cb
208
209=item filter_w => $cb
210
211These exist, but are undocumented at this time.
212
213=back 279=back
214 280
215=cut 281=cut
216 282
217sub new { 283sub new {
221 287
222 $self->{fh} or Carp::croak "mandatory argument fh is missing"; 288 $self->{fh} or Carp::croak "mandatory argument fh is missing";
223 289
224 AnyEvent::Util::fh_nonblocking $self->{fh}, 1; 290 AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
225 291
226 if ($self->{tls}) {
227 require Net::SSLeay;
228 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx}); 292 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
229 } 293 if $self->{tls};
230 294
231 $self->{_activity} = AnyEvent->now; 295 $self->{_activity} = AnyEvent->now;
232 $self->_timeout; 296 $self->_timeout;
233 297
234 $self->on_drain (delete $self->{on_drain}) if $self->{on_drain}; 298 $self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
299 $self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
300
301 $self->start_read
302 if $self->{on_read};
235 303
236 $self 304 $self
237} 305}
238 306
239sub _shutdown { 307sub _shutdown {
242 delete $self->{_tw}; 310 delete $self->{_tw};
243 delete $self->{_rw}; 311 delete $self->{_rw};
244 delete $self->{_ww}; 312 delete $self->{_ww};
245 delete $self->{fh}; 313 delete $self->{fh};
246 314
247 $self->stoptls; 315 &_freetls;
316
317 delete $self->{on_read};
318 delete $self->{_queue};
248} 319}
249 320
250sub _error { 321sub _error {
251 my ($self, $errno, $fatal) = @_; 322 my ($self, $errno, $fatal) = @_;
252 323
255 326
256 $! = $errno; 327 $! = $errno;
257 328
258 if ($self->{on_error}) { 329 if ($self->{on_error}) {
259 $self->{on_error}($self, $fatal); 330 $self->{on_error}($self, $fatal);
260 } else { 331 } elsif ($self->{fh}) {
261 Carp::croak "AnyEvent::Handle uncaught error: $!"; 332 Carp::croak "AnyEvent::Handle uncaught error: $!";
262 } 333 }
263} 334}
264 335
265=item $fh = $handle->fh 336=item $fh = $handle->fh
266 337
267This method returns the file handle of the L<AnyEvent::Handle> object. 338This method returns the file handle used to create the L<AnyEvent::Handle> object.
268 339
269=cut 340=cut
270 341
271sub fh { $_[0]{fh} } 342sub fh { $_[0]{fh} }
272 343
290 $_[0]{on_eof} = $_[1]; 361 $_[0]{on_eof} = $_[1];
291} 362}
292 363
293=item $handle->on_timeout ($cb) 364=item $handle->on_timeout ($cb)
294 365
295Replace the current C<on_timeout> callback, or disables the callback 366Replace the current C<on_timeout> callback, or disables the callback (but
296(but not the timeout) if C<$cb> = C<undef>. See C<timeout> constructor 367not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
297argument. 368argument and method.
298 369
299=cut 370=cut
300 371
301sub on_timeout { 372sub on_timeout {
302 $_[0]{on_timeout} = $_[1]; 373 $_[0]{on_timeout} = $_[1];
374}
375
376=item $handle->autocork ($boolean)
377
378Enables or disables the current autocork behaviour (see C<autocork>
379constructor argument).
380
381=cut
382
383=item $handle->no_delay ($boolean)
384
385Enables or disables the C<no_delay> setting (see constructor argument of
386the same name for details).
387
388=cut
389
390sub no_delay {
391 $_[0]{no_delay} = $_[1];
392
393 eval {
394 local $SIG{__DIE__};
395 setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
396 };
303} 397}
304 398
305############################################################################# 399#############################################################################
306 400
307=item $handle->timeout ($seconds) 401=item $handle->timeout ($seconds)
385 my ($self, $cb) = @_; 479 my ($self, $cb) = @_;
386 480
387 $self->{on_drain} = $cb; 481 $self->{on_drain} = $cb;
388 482
389 $cb->($self) 483 $cb->($self)
390 if $cb && $self->{low_water_mark} >= length $self->{wbuf}; 484 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
391} 485}
392 486
393=item $handle->push_write ($data) 487=item $handle->push_write ($data)
394 488
395Queues the given scalar to be written. You can push as much data as you 489Queues the given scalar to be written. You can push as much data as you
412 substr $self->{wbuf}, 0, $len, ""; 506 substr $self->{wbuf}, 0, $len, "";
413 507
414 $self->{_activity} = AnyEvent->now; 508 $self->{_activity} = AnyEvent->now;
415 509
416 $self->{on_drain}($self) 510 $self->{on_drain}($self)
417 if $self->{low_water_mark} >= length $self->{wbuf} 511 if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
418 && $self->{on_drain}; 512 && $self->{on_drain};
419 513
420 delete $self->{_ww} unless length $self->{wbuf}; 514 delete $self->{_ww} unless length $self->{wbuf};
421 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) { 515 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
422 $self->_error ($!, 1); 516 $self->_error ($!, 1);
423 } 517 }
424 }; 518 };
425 519
426 # try to write data immediately 520 # try to write data immediately
427 $cb->(); 521 $cb->() unless $self->{autocork};
428 522
429 # if still data left in wbuf, we need to poll 523 # if still data left in wbuf, we need to poll
430 $self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb) 524 $self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
431 if length $self->{wbuf}; 525 if length $self->{wbuf};
432 }; 526 };
446 540
447 @_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write") 541 @_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
448 ->($self, @_); 542 ->($self, @_);
449 } 543 }
450 544
451 if ($self->{filter_w}) { 545 if ($self->{tls}) {
452 $self->{filter_w}($self, \$_[0]); 546 $self->{_tls_wbuf} .= $_[0];
547
548 &_dotls ($self);
453 } else { 549 } else {
454 $self->{wbuf} .= $_[0]; 550 $self->{wbuf} .= $_[0];
455 $self->_drain_wbuf; 551 $self->_drain_wbuf;
456 } 552 }
457} 553}
474=cut 570=cut
475 571
476register_write_type netstring => sub { 572register_write_type netstring => sub {
477 my ($self, $string) = @_; 573 my ($self, $string) = @_;
478 574
479 sprintf "%d:%s,", (length $string), $string 575 (length $string) . ":$string,"
480}; 576};
481 577
482=item packstring => $format, $data 578=item packstring => $format, $data
483 579
484An octet string prefixed with an encoded length. The encoding C<$format> 580An octet string prefixed with an encoded length. The encoding C<$format>
489=cut 585=cut
490 586
491register_write_type packstring => sub { 587register_write_type packstring => sub {
492 my ($self, $format, $string) = @_; 588 my ($self, $format, $string) = @_;
493 589
494 pack "$format/a", $string 590 pack "$format/a*", $string
495}; 591};
496 592
497=item json => $array_or_hashref 593=item json => $array_or_hashref
498 594
499Encodes the given hash or array reference into a JSON object. Unless you 595Encodes the given hash or array reference into a JSON object. Unless you
533 629
534 $self->{json} ? $self->{json}->encode ($ref) 630 $self->{json} ? $self->{json}->encode ($ref)
535 : JSON::encode_json ($ref) 631 : JSON::encode_json ($ref)
536}; 632};
537 633
634=item storable => $reference
635
636Freezes the given reference using L<Storable> and writes it to the
637handle. Uses the C<nfreeze> format.
638
639=cut
640
641register_write_type storable => sub {
642 my ($self, $ref) = @_;
643
644 require Storable;
645
646 pack "w/a*", Storable::nfreeze ($ref)
647};
648
538=back 649=back
539 650
540=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args) 651=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
541 652
542This function (not method) lets you add your own types to C<push_write>. 653This function (not method) lets you add your own types to C<push_write>.
564ways, the "simple" way, using only C<on_read> and the "complex" way, using 675ways, the "simple" way, using only C<on_read> and the "complex" way, using
565a queue. 676a queue.
566 677
567In the simple case, you just install an C<on_read> callback and whenever 678In the simple case, you just install an C<on_read> callback and whenever
568new data arrives, it will be called. You can then remove some data (if 679new data arrives, it will be called. You can then remove some data (if
569enough is there) from the read buffer (C<< $handle->rbuf >>) if you want 680enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
570or not. 681leave the data there if you want to accumulate more (e.g. when only a
682partial message has been received so far).
571 683
572In the more complex case, you want to queue multiple callbacks. In this 684In the more complex case, you want to queue multiple callbacks. In this
573case, AnyEvent::Handle will call the first queued callback each time new 685case, AnyEvent::Handle will call the first queued callback each time new
574data arrives (also the first time it is queued) and removes it when it has 686data arrives (also the first time it is queued) and removes it when it has
575done its job (see C<push_read>, below). 687done its job (see C<push_read>, below).
593 # handle xml 705 # handle xml
594 }); 706 });
595 }); 707 });
596 }); 708 });
597 709
598Example 2: Implement a client for a protocol that replies either with 710Example 2: Implement a client for a protocol that replies either with "OK"
599"OK" and another line or "ERROR" for one request, and 64 bytes for the 711and another line or "ERROR" for the first request that is sent, and 64
600second request. Due tot he availability of a full queue, we can just 712bytes for the second request. Due to the availability of a queue, we can
601pipeline sending both requests and manipulate the queue as necessary in 713just pipeline sending both requests and manipulate the queue as necessary
602the callbacks: 714in the callbacks.
603 715
604 # request one 716When the first callback is called and sees an "OK" response, it will
717C<unshift> another line-read. This line-read will be queued I<before> the
71864-byte chunk callback.
719
720 # request one, returns either "OK + extra line" or "ERROR"
605 $handle->push_write ("request 1\015\012"); 721 $handle->push_write ("request 1\015\012");
606 722
607 # we expect "ERROR" or "OK" as response, so push a line read 723 # we expect "ERROR" or "OK" as response, so push a line read
608 $handle->push_read (line => sub { 724 $handle->push_read (line => sub {
609 # if we got an "OK", we have to _prepend_ another line, 725 # if we got an "OK", we have to _prepend_ another line,
616 ... 732 ...
617 }); 733 });
618 } 734 }
619 }); 735 });
620 736
621 # request two 737 # request two, simply returns 64 octets
622 $handle->push_write ("request 2\015\012"); 738 $handle->push_write ("request 2\015\012");
623 739
624 # simply read 64 bytes, always 740 # simply read 64 bytes, always
625 $handle->push_read (chunk => 64, sub { 741 $handle->push_read (chunk => 64, sub {
626 my $response = $_[1]; 742 my $response = $_[1];
638 754
639 if ( 755 if (
640 defined $self->{rbuf_max} 756 defined $self->{rbuf_max}
641 && $self->{rbuf_max} < length $self->{rbuf} 757 && $self->{rbuf_max} < length $self->{rbuf}
642 ) { 758 ) {
643 return $self->_error (&Errno::ENOSPC, 1); 759 $self->_error (&Errno::ENOSPC, 1), return;
644 } 760 }
645 761
646 while () { 762 while () {
647 no strict 'refs';
648
649 my $len = length $self->{rbuf}; 763 my $len = length $self->{rbuf};
650 764
651 if (my $cb = shift @{ $self->{_queue} }) { 765 if (my $cb = shift @{ $self->{_queue} }) {
652 unless ($cb->($self)) { 766 unless ($cb->($self)) {
653 if ($self->{_eof}) { 767 if ($self->{_eof}) {
654 # no progress can be made (not enough data and no data forthcoming) 768 # no progress can be made (not enough data and no data forthcoming)
655 $self->_error (&Errno::EPIPE, 1), last; 769 $self->_error (&Errno::EPIPE, 1), return;
656 } 770 }
657 771
658 unshift @{ $self->{_queue} }, $cb; 772 unshift @{ $self->{_queue} }, $cb;
659 last; 773 last;
660 } 774 }
668 && !@{ $self->{_queue} } # and the queue is still empty 782 && !@{ $self->{_queue} } # and the queue is still empty
669 && $self->{on_read} # but we still have on_read 783 && $self->{on_read} # but we still have on_read
670 ) { 784 ) {
671 # no further data will arrive 785 # no further data will arrive
672 # so no progress can be made 786 # so no progress can be made
673 $self->_error (&Errno::EPIPE, 1), last 787 $self->_error (&Errno::EPIPE, 1), return
674 if $self->{_eof}; 788 if $self->{_eof};
675 789
676 last; # more data might arrive 790 last; # more data might arrive
677 } 791 }
678 } else { 792 } else {
679 # read side becomes idle 793 # read side becomes idle
680 delete $self->{_rw}; 794 delete $self->{_rw} unless $self->{tls};
681 last; 795 last;
682 } 796 }
683 } 797 }
684 798
799 if ($self->{_eof}) {
800 if ($self->{on_eof}) {
685 $self->{on_eof}($self) 801 $self->{on_eof}($self)
686 if $self->{_eof} && $self->{on_eof}; 802 } else {
803 $self->_error (0, 1);
804 }
805 }
687 806
688 # may need to restart read watcher 807 # may need to restart read watcher
689 unless ($self->{_rw}) { 808 unless ($self->{_rw}) {
690 $self->start_read 809 $self->start_read
691 if $self->{on_read} || @{ $self->{_queue} }; 810 if $self->{on_read} || @{ $self->{_queue} };
817 $cb->($_[0], substr $_[0]{rbuf}, 0, $len, ""); 936 $cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
818 1 937 1
819 } 938 }
820}; 939};
821 940
822# compatibility with older API
823sub push_read_chunk {
824 $_[0]->push_read (chunk => $_[1], $_[2]);
825}
826
827sub unshift_read_chunk {
828 $_[0]->unshift_read (chunk => $_[1], $_[2]);
829}
830
831=item line => [$eol, ]$cb->($handle, $line, $eol) 941=item line => [$eol, ]$cb->($handle, $line, $eol)
832 942
833The callback will be called only once a full line (including the end of 943The callback will be called only once a full line (including the end of
834line marker, C<$eol>) has been read. This line (excluding the end of line 944line marker, C<$eol>) has been read. This line (excluding the end of line
835marker) will be passed to the callback as second argument (C<$line>), and 945marker) will be passed to the callback as second argument (C<$line>), and
850=cut 960=cut
851 961
852register_read_type line => sub { 962register_read_type line => sub {
853 my ($self, $cb, $eol) = @_; 963 my ($self, $cb, $eol) = @_;
854 964
855 $eol = qr|(\015?\012)| if @_ < 3; 965 if (@_ < 3) {
966 # this is more than twice as fast as the generic code below
967 sub {
968 $_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
969
970 $cb->($_[0], $1, $2);
971 1
972 }
973 } else {
856 $eol = quotemeta $eol unless ref $eol; 974 $eol = quotemeta $eol unless ref $eol;
857 $eol = qr|^(.*?)($eol)|s; 975 $eol = qr|^(.*?)($eol)|s;
858 976
859 sub { 977 sub {
860 $_[0]{rbuf} =~ s/$eol// or return; 978 $_[0]{rbuf} =~ s/$eol// or return;
861 979
862 $cb->($_[0], $1, $2); 980 $cb->($_[0], $1, $2);
981 1
863 1 982 }
864 } 983 }
865}; 984};
866
867# compatibility with older API
868sub push_read_line {
869 my $self = shift;
870 $self->push_read (line => @_);
871}
872
873sub unshift_read_line {
874 my $self = shift;
875 $self->unshift_read (line => @_);
876}
877 985
878=item regex => $accept[, $reject[, $skip], $cb->($handle, $data) 986=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
879 987
880Makes a regex match against the regex object C<$accept> and returns 988Makes a regex match against the regex object C<$accept> and returns
881everything up to and including the match. 989everything up to and including the match.
986An octet string prefixed with an encoded length. The encoding C<$format> 1094An octet string prefixed with an encoded length. The encoding C<$format>
987uses the same format as a Perl C<pack> format, but must specify a single 1095uses the same format as a Perl C<pack> format, but must specify a single
988integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an 1096integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
989optional C<!>, C<< < >> or C<< > >> modifier). 1097optional C<!>, C<< < >> or C<< > >> modifier).
990 1098
991DNS over TCP uses a prefix of C<n>, EPP uses a prefix of C<N>. 1099For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
1100EPP uses a prefix of C<N> (4 octtes).
992 1101
993Example: read a block of data prefixed by its length in BER-encoded 1102Example: read a block of data prefixed by its length in BER-encoded
994format (very efficient). 1103format (very efficient).
995 1104
996 $handle->push_read (packstring => "w", sub { 1105 $handle->push_read (packstring => "w", sub {
1002register_read_type packstring => sub { 1111register_read_type packstring => sub {
1003 my ($self, $cb, $format) = @_; 1112 my ($self, $cb, $format) = @_;
1004 1113
1005 sub { 1114 sub {
1006 # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method 1115 # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
1007 defined (my $len = eval { unpack $format, $_[0]->{rbuf} }) 1116 defined (my $len = eval { unpack $format, $_[0]{rbuf} })
1008 or return; 1117 or return;
1009 1118
1119 $format = length pack $format, $len;
1120
1121 # bypass unshift if we already have the remaining chunk
1122 if ($format + $len <= length $_[0]{rbuf}) {
1123 my $data = substr $_[0]{rbuf}, $format, $len;
1124 substr $_[0]{rbuf}, 0, $format + $len, "";
1125 $cb->($_[0], $data);
1126 } else {
1010 # remove prefix 1127 # remove prefix
1011 substr $_[0]->{rbuf}, 0, (length pack $format, $len), ""; 1128 substr $_[0]{rbuf}, 0, $format, "";
1012 1129
1013 # read rest 1130 # read remaining chunk
1014 $_[0]->unshift_read (chunk => $len, $cb); 1131 $_[0]->unshift_read (chunk => $len, $cb);
1132 }
1015 1133
1016 1 1134 1
1017 } 1135 }
1018}; 1136};
1019 1137
1034the C<json> write type description, above, for an actual example. 1152the C<json> write type description, above, for an actual example.
1035 1153
1036=cut 1154=cut
1037 1155
1038register_read_type json => sub { 1156register_read_type json => sub {
1039 my ($self, $cb, $accept, $reject, $skip) = @_; 1157 my ($self, $cb) = @_;
1040 1158
1041 require JSON; 1159 require JSON;
1042 1160
1043 my $data; 1161 my $data;
1044 my $rbuf = \$self->{rbuf}; 1162 my $rbuf = \$self->{rbuf};
1059 () 1177 ()
1060 } 1178 }
1061 } 1179 }
1062}; 1180};
1063 1181
1182=item storable => $cb->($handle, $ref)
1183
1184Deserialises a L<Storable> frozen representation as written by the
1185C<storable> write type (BER-encoded length prefix followed by nfreeze'd
1186data).
1187
1188Raises C<EBADMSG> error if the data could not be decoded.
1189
1190=cut
1191
1192register_read_type storable => sub {
1193 my ($self, $cb) = @_;
1194
1195 require Storable;
1196
1197 sub {
1198 # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
1199 defined (my $len = eval { unpack "w", $_[0]{rbuf} })
1200 or return;
1201
1202 my $format = length pack "w", $len;
1203
1204 # bypass unshift if we already have the remaining chunk
1205 if ($format + $len <= length $_[0]{rbuf}) {
1206 my $data = substr $_[0]{rbuf}, $format, $len;
1207 substr $_[0]{rbuf}, 0, $format + $len, "";
1208 $cb->($_[0], Storable::thaw ($data));
1209 } else {
1210 # remove prefix
1211 substr $_[0]{rbuf}, 0, $format, "";
1212
1213 # read remaining chunk
1214 $_[0]->unshift_read (chunk => $len, sub {
1215 if (my $ref = eval { Storable::thaw ($_[1]) }) {
1216 $cb->($_[0], $ref);
1217 } else {
1218 $self->_error (&Errno::EBADMSG);
1219 }
1220 });
1221 }
1222
1223 1
1224 }
1225};
1226
1064=back 1227=back
1065 1228
1066=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args) 1229=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
1067 1230
1068This function (not method) lets you add your own types to C<push_read>. 1231This function (not method) lets you add your own types to C<push_read>.
1095Note that AnyEvent::Handle will automatically C<start_read> for you when 1258Note that AnyEvent::Handle will automatically C<start_read> for you when
1096you change the C<on_read> callback or push/unshift a read callback, and it 1259you change the C<on_read> callback or push/unshift a read callback, and it
1097will automatically C<stop_read> for you when neither C<on_read> is set nor 1260will automatically C<stop_read> for you when neither C<on_read> is set nor
1098there are any read requests in the queue. 1261there are any read requests in the queue.
1099 1262
1263These methods will have no effect when in TLS mode (as TLS doesn't support
1264half-duplex connections).
1265
1100=cut 1266=cut
1101 1267
1102sub stop_read { 1268sub stop_read {
1103 my ($self) = @_; 1269 my ($self) = @_;
1104 1270
1105 delete $self->{_rw}; 1271 delete $self->{_rw} unless $self->{tls};
1106} 1272}
1107 1273
1108sub start_read { 1274sub start_read {
1109 my ($self) = @_; 1275 my ($self) = @_;
1110 1276
1111 unless ($self->{_rw} || $self->{_eof}) { 1277 unless ($self->{_rw} || $self->{_eof}) {
1112 Scalar::Util::weaken $self; 1278 Scalar::Util::weaken $self;
1113 1279
1114 $self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub { 1280 $self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
1115 my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf}; 1281 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1116 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf; 1282 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
1117 1283
1118 if ($len > 0) { 1284 if ($len > 0) {
1119 $self->{_activity} = AnyEvent->now; 1285 $self->{_activity} = AnyEvent->now;
1120 1286
1121 $self->{filter_r} 1287 if ($self->{tls}) {
1122 ? $self->{filter_r}($self, $rbuf) 1288 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1123 : $self->{_in_drain} || $self->_drain_rbuf; 1289
1290 &_dotls ($self);
1291 } else {
1292 $self->_drain_rbuf unless $self->{_in_drain};
1293 }
1124 1294
1125 } elsif (defined $len) { 1295 } elsif (defined $len) {
1126 delete $self->{_rw}; 1296 delete $self->{_rw};
1127 $self->{_eof} = 1; 1297 $self->{_eof} = 1;
1128 $self->_drain_rbuf unless $self->{_in_drain}; 1298 $self->_drain_rbuf unless $self->{_in_drain};
1132 } 1302 }
1133 }); 1303 });
1134 } 1304 }
1135} 1305}
1136 1306
1307# poll the write BIO and send the data if applicable
1137sub _dotls { 1308sub _dotls {
1138 my ($self) = @_; 1309 my ($self) = @_;
1139 1310
1140 my $buf; 1311 my $tmp;
1141 1312
1142 if (length $self->{_tls_wbuf}) { 1313 if (length $self->{_tls_wbuf}) {
1143 while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) { 1314 while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
1144 substr $self->{_tls_wbuf}, 0, $len, ""; 1315 substr $self->{_tls_wbuf}, 0, $tmp, "";
1145 } 1316 }
1146 } 1317 }
1147 1318
1148 if (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1149 $self->{wbuf} .= $buf;
1150 $self->_drain_wbuf;
1151 }
1152
1153 while (defined ($buf = Net::SSLeay::read ($self->{tls}))) { 1319 while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
1154 if (length $buf) { 1320 unless (length $tmp) {
1155 $self->{rbuf} .= $buf;
1156 $self->_drain_rbuf unless $self->{_in_drain};
1157 } else {
1158 # let's treat SSL-eof as we treat normal EOF 1321 # let's treat SSL-eof as we treat normal EOF
1322 delete $self->{_rw};
1159 $self->{_eof} = 1; 1323 $self->{_eof} = 1;
1160 $self->_shutdown; 1324 &_freetls;
1161 return;
1162 } 1325 }
1163 }
1164 1326
1327 $self->{rbuf} .= $tmp;
1328 $self->_drain_rbuf unless $self->{_in_drain};
1329 $self->{tls} or return; # tls session might have gone away in callback
1330 }
1331
1165 my $err = Net::SSLeay::get_error ($self->{tls}, -1); 1332 $tmp = Net::SSLeay::get_error ($self->{tls}, -1);
1166 1333
1167 if ($err!= Net::SSLeay::ERROR_WANT_READ ()) { 1334 if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
1168 if ($err == Net::SSLeay::ERROR_SYSCALL ()) { 1335 if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
1169 return $self->_error ($!, 1); 1336 return $self->_error ($!, 1);
1170 } elsif ($err == Net::SSLeay::ERROR_SSL ()) { 1337 } elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
1171 return $self->_error (&Errno::EIO, 1); 1338 return $self->_error (&Errno::EIO, 1);
1172 } 1339 }
1173 1340
1174 # all others are fine for our purposes 1341 # all other errors are fine for our purposes
1342 }
1343
1344 while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1345 $self->{wbuf} .= $tmp;
1346 $self->_drain_wbuf;
1175 } 1347 }
1176} 1348}
1177 1349
1178=item $handle->starttls ($tls[, $tls_ctx]) 1350=item $handle->starttls ($tls[, $tls_ctx])
1179 1351
1189 1361
1190The TLS connection object will end up in C<< $handle->{tls} >> after this 1362The TLS connection object will end up in C<< $handle->{tls} >> after this
1191call and can be used or changed to your liking. Note that the handshake 1363call and can be used or changed to your liking. Note that the handshake
1192might have already started when this function returns. 1364might have already started when this function returns.
1193 1365
1366If it an error to start a TLS handshake more than once per
1367AnyEvent::Handle object (this is due to bugs in OpenSSL).
1368
1194=cut 1369=cut
1195 1370
1196sub starttls { 1371sub starttls {
1197 my ($self, $ssl, $ctx) = @_; 1372 my ($self, $ssl, $ctx) = @_;
1198 1373
1199 $self->stoptls; 1374 require Net::SSLeay;
1200 1375
1376 Carp::croak "it is an error to call starttls more than once on an Anyevent::Handle object"
1377 if $self->{tls};
1378
1201 if ($ssl eq "accept") { 1379 if ($ssl eq "accept") {
1202 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1380 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
1203 Net::SSLeay::set_accept_state ($ssl); 1381 Net::SSLeay::set_accept_state ($ssl);
1204 } elsif ($ssl eq "connect") { 1382 } elsif ($ssl eq "connect") {
1205 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1383 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
1211 # basically, this is deep magic (because SSL_read should have the same issues) 1389 # basically, this is deep magic (because SSL_read should have the same issues)
1212 # but the openssl maintainers basically said: "trust us, it just works". 1390 # but the openssl maintainers basically said: "trust us, it just works".
1213 # (unfortunately, we have to hardcode constants because the abysmally misdesigned 1391 # (unfortunately, we have to hardcode constants because the abysmally misdesigned
1214 # and mismaintained ssleay-module doesn't even offer them). 1392 # and mismaintained ssleay-module doesn't even offer them).
1215 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html 1393 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
1394 #
1395 # in short: this is a mess.
1396 #
1397 # note that we do not try to keep the length constant between writes as we are required to do.
1398 # we assume that most (but not all) of this insanity only applies to non-blocking cases,
1399 # and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
1400 # have identity issues in that area.
1216 Net::SSLeay::CTX_set_mode ($self->{tls}, 1401 Net::SSLeay::CTX_set_mode ($self->{tls},
1217 (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1) 1402 (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
1218 | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2)); 1403 | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
1219 1404
1220 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 1405 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1221 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 1406 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1222 1407
1223 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio}); 1408 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
1224 1409
1225 $self->{filter_w} = sub { 1410 &_dotls; # need to trigger the initial handshake
1226 $_[0]{_tls_wbuf} .= ${$_[1]}; 1411 $self->start_read; # make sure we actually do read
1227 &_dotls;
1228 };
1229 $self->{filter_r} = sub {
1230 Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
1231 &_dotls;
1232 };
1233} 1412}
1234 1413
1235=item $handle->stoptls 1414=item $handle->stoptls
1236 1415
1237Destroys the SSL connection, if any. Partial read or write data will be 1416Shuts down the SSL connection - this makes a proper EOF handshake by
1238lost. 1417sending a close notify to the other side, but since OpenSSL doesn't
1418support non-blocking shut downs, it is not possible to re-use the stream
1419afterwards.
1239 1420
1240=cut 1421=cut
1241 1422
1242sub stoptls { 1423sub stoptls {
1243 my ($self) = @_; 1424 my ($self) = @_;
1244 1425
1426 if ($self->{tls}) {
1427 Net::SSLeay::shutdown ($self->{tls});
1428
1429 &_dotls;
1430
1431 # we don't give a shit. no, we do, but we can't. no...
1432 # we, we... have to use openssl :/
1433 &_freetls;
1434 }
1435}
1436
1437sub _freetls {
1438 my ($self) = @_;
1439
1440 return unless $self->{tls};
1441
1245 Net::SSLeay::free (delete $self->{tls}) if $self->{tls}; 1442 Net::SSLeay::free (delete $self->{tls});
1246 1443
1247 delete $self->{_rbio}; 1444 delete @$self{qw(_rbio _wbio _tls_wbuf)};
1248 delete $self->{_wbio};
1249 delete $self->{_tls_wbuf};
1250 delete $self->{filter_r};
1251 delete $self->{filter_w};
1252} 1445}
1253 1446
1254sub DESTROY { 1447sub DESTROY {
1255 my $self = shift; 1448 my $self = shift;
1256 1449
1257 $self->stoptls; 1450 &_freetls;
1451
1452 my $linger = exists $self->{linger} ? $self->{linger} : 3600;
1453
1454 if ($linger && length $self->{wbuf}) {
1455 my $fh = delete $self->{fh};
1456 my $wbuf = delete $self->{wbuf};
1457
1458 my @linger;
1459
1460 push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
1461 my $len = syswrite $fh, $wbuf, length $wbuf;
1462
1463 if ($len > 0) {
1464 substr $wbuf, 0, $len, "";
1465 } else {
1466 @linger = (); # end
1467 }
1468 });
1469 push @linger, AnyEvent->timer (after => $linger, cb => sub {
1470 @linger = ();
1471 });
1472 }
1473}
1474
1475=item $handle->destroy
1476
1477Shut's down the handle object as much as possible - this call ensures that
1478no further callbacks will be invoked and resources will be freed as much
1479as possible. You must not call any methods on the object afterwards.
1480
1481The handle might still linger in the background and write out remaining
1482data, as specified by the C<linger> option, however.
1483
1484=cut
1485
1486sub destroy {
1487 my ($self) = @_;
1488
1489 $self->DESTROY;
1490 %$self = ();
1258} 1491}
1259 1492
1260=item AnyEvent::Handle::TLS_CTX 1493=item AnyEvent::Handle::TLS_CTX
1261 1494
1262This function creates and returns the Net::SSLeay::CTX object used by 1495This function creates and returns the Net::SSLeay::CTX object used by
1292 } 1525 }
1293} 1526}
1294 1527
1295=back 1528=back
1296 1529
1530
1531=head1 NONFREQUENTLY ASKED QUESTIONS
1532
1533=over 4
1534
1535=item How do I read data until the other side closes the connection?
1536
1537If you just want to read your data into a perl scalar, the easiest way
1538to achieve this is by setting an C<on_read> callback that does nothing,
1539clearing the C<on_eof> callback and in the C<on_error> callback, the data
1540will be in C<$_[0]{rbuf}>:
1541
1542 $handle->on_read (sub { });
1543 $handle->on_eof (undef);
1544 $handle->on_error (sub {
1545 my $data = delete $_[0]{rbuf};
1546 undef $handle;
1547 });
1548
1549The reason to use C<on_error> is that TCP connections, due to latencies
1550and packets loss, might get closed quite violently with an error, when in
1551fact, all data has been received.
1552
1553It is usually better to use acknowledgements when transfering data,
1554to make sure the other side hasn't just died and you got the data
1555intact. This is also one reason why so many internet protocols have an
1556explicit QUIT command.
1557
1558
1559=item I don't want to destroy the handle too early - how do I wait until
1560all data has been written?
1561
1562After writing your last bits of data, set the C<on_drain> callback
1563and destroy the handle in there - with the default setting of
1564C<low_water_mark> this will be called precisely when all data has been
1565written to the socket:
1566
1567 $handle->push_write (...);
1568 $handle->on_drain (sub {
1569 warn "all data submitted to the kernel\n";
1570 undef $handle;
1571 });
1572
1573=item I get different callback invocations in TLS mode/Why can't I pause
1574reading?
1575
1576Unlike, say, TCP, TLS conenctions do not consist of two independent
1577communication channels, one for each direction. Or put differently. the
1578read and write directions are not independent of each other: you cannot
1579write data unless you are also prepared to read, and vice versa.
1580
1581This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
1582callback invocations when you are not expecting any read data - the reason
1583is that AnyEvent::Handle always reads in TLS mode.
1584
1585During the connection, you have to make sure that you always have a
1586non-empty read-queue, or an C<on_read> watcher. At the end of the
1587connection (or when you no longer want to use it) you can call the
1588C<destroy> method.
1589
1590=back
1591
1592
1297=head1 SUBCLASSING AnyEvent::Handle 1593=head1 SUBCLASSING AnyEvent::Handle
1298 1594
1299In many cases, you might want to subclass AnyEvent::Handle. 1595In many cases, you might want to subclass AnyEvent::Handle.
1300 1596
1301To make this easier, a given version of AnyEvent::Handle uses these 1597To make this easier, a given version of AnyEvent::Handle uses these
1304=over 4 1600=over 4
1305 1601
1306=item * all constructor arguments become object members. 1602=item * all constructor arguments become object members.
1307 1603
1308At least initially, when you pass a C<tls>-argument to the constructor it 1604At least initially, when you pass a C<tls>-argument to the constructor it
1309will end up in C<< $handle->{tls} >>. Those members might be changes or 1605will end up in C<< $handle->{tls} >>. Those members might be changed or
1310mutated later on (for example C<tls> will hold the TLS connection object). 1606mutated later on (for example C<tls> will hold the TLS connection object).
1311 1607
1312=item * other object member names are prefixed with an C<_>. 1608=item * other object member names are prefixed with an C<_>.
1313 1609
1314All object members not explicitly documented (internal use) are prefixed 1610All object members not explicitly documented (internal use) are prefixed

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