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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.90 by root, Mon Sep 29 02:08:57 2008 UTC vs.
Revision 1.108 by root, Tue Jan 6 20:08:05 2009 UTC

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 = 4.234; 19our $VERSION = 4.331;
20 20
21=head1 SYNOPSIS 21=head1 SYNOPSIS
22 22
23 use AnyEvent; 23 use AnyEvent;
24 use AnyEvent::Handle; 24 use AnyEvent::Handle;
27 27
28 my $handle = 28 my $handle =
29 AnyEvent::Handle->new ( 29 AnyEvent::Handle->new (
30 fh => \*STDIN, 30 fh => \*STDIN,
31 on_eof => sub { 31 on_eof => sub {
32 $cv->broadcast; 32 $cv->send;
33 }, 33 },
34 ); 34 );
35 35
36 # send some request line 36 # send some request line
37 $handle->push_write ("getinfo\015\012"); 37 $handle->push_write ("getinfo\015\012");
59treatment of characters applies to this module as well. 59treatment of characters applies to this module as well.
60 60
61All callbacks will be invoked with the handle object as their first 61All callbacks will be invoked with the handle object as their first
62argument. 62argument.
63 63
64=head2 SIGPIPE is not handled by this module
65
66SIGPIPE is not handled by this module, so one of the practical
67requirements of using it is to ignore SIGPIPE (C<$SIG{PIPE} =
68'IGNORE'>). At least, this is highly recommend in a networked program: If
69you use AnyEvent::Handle in a filter program (like sort), exiting on
70SIGPIPE is probably the right thing to do.
71
72=head1 METHODS 64=head1 METHODS
73 65
74=over 4 66=over 4
75 67
76=item B<new (%args)> 68=item B<new (%args)>
92Set the callback to be called when an end-of-file condition is detected, 84Set the callback to be called when an end-of-file condition is detected,
93i.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
94connection cleanly. 86connection cleanly.
95 87
96For sockets, this just means that the other side has stopped sending data, 88For sockets, this just means that the other side has stopped sending data,
97you can still try to write data, and, in fact, one can return from the eof 89you can still try to write data, and, in fact, one can return from the EOF
98callback and continue writing data, as only the read part has been shut 90callback and continue writing data, as only the read part has been shut
99down. 91down.
100 92
101While not mandatory, it is I<highly> recommended to set an eof callback, 93While not mandatory, it is I<highly> recommended to set an EOF callback,
102otherwise 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
103waiting for data. 95waiting for data.
104 96
105If an EOF condition has been detected but no C<on_eof> callback has been 97If an EOF condition has been detected but no C<on_eof> callback has been
106set, then a fatal error will be raised with C<$!> set to <0>. 98set, then a fatal error will be raised with C<$!> set to <0>.
240write data and will install a watcher that will write this data to the 232write data and will install a watcher that will write this data to the
241socket. No errors will be reported (this mostly matches how the operating 233socket. No errors will be reported (this mostly matches how the operating
242system treats outstanding data at socket close time). 234system treats outstanding data at socket close time).
243 235
244This will not work for partial TLS data that could not be encoded 236This will not work for partial TLS data that could not be encoded
245yet. This data will be lost. 237yet. This data will be lost. Calling the C<stoptls> method in time might
238help.
246 239
247=item tls => "accept" | "connect" | Net::SSLeay::SSL object 240=item tls => "accept" | "connect" | Net::SSLeay::SSL object
248 241
249When this parameter is given, it enables TLS (SSL) mode, that means 242When this parameter is given, it enables TLS (SSL) mode, that means
250AnyEvent will start a TLS handshake as soon as the conenction has been 243AnyEvent will start a TLS handshake as soon as the conenction has been
281texts. 274texts.
282 275
283Note 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
284use this functionality, as AnyEvent does not have a dependency itself. 277use this functionality, as AnyEvent does not have a dependency itself.
285 278
286=item filter_r => $cb
287
288=item filter_w => $cb
289
290These exist, but are undocumented at this time. (They are used internally
291by the TLS code).
292
293=back 279=back
294 280
295=cut 281=cut
296 282
297sub new { 283sub new {
301 287
302 $self->{fh} or Carp::croak "mandatory argument fh is missing"; 288 $self->{fh} or Carp::croak "mandatory argument fh is missing";
303 289
304 AnyEvent::Util::fh_nonblocking $self->{fh}, 1; 290 AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
305 291
306 if ($self->{tls}) {
307 require Net::SSLeay;
308 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx}); 292 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
309 } 293 if $self->{tls};
310 294
311 $self->{_activity} = AnyEvent->now; 295 $self->{_activity} = AnyEvent->now;
312 $self->_timeout; 296 $self->_timeout;
313 297
314 $self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain}; 298 $self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
326 delete $self->{_tw}; 310 delete $self->{_tw};
327 delete $self->{_rw}; 311 delete $self->{_rw};
328 delete $self->{_ww}; 312 delete $self->{_ww};
329 delete $self->{fh}; 313 delete $self->{fh};
330 314
331 $self->stoptls; 315 &_freetls;
332 316
333 delete $self->{on_read}; 317 delete $self->{on_read};
334 delete $self->{_queue}; 318 delete $self->{_queue};
335} 319}
336 320
342 326
343 $! = $errno; 327 $! = $errno;
344 328
345 if ($self->{on_error}) { 329 if ($self->{on_error}) {
346 $self->{on_error}($self, $fatal); 330 $self->{on_error}($self, $fatal);
347 } else { 331 } elsif ($self->{fh}) {
348 Carp::croak "AnyEvent::Handle uncaught error: $!"; 332 Carp::croak "AnyEvent::Handle uncaught error: $!";
349 } 333 }
350} 334}
351 335
352=item $fh = $handle->fh 336=item $fh = $handle->fh
390} 374}
391 375
392=item $handle->autocork ($boolean) 376=item $handle->autocork ($boolean)
393 377
394Enables or disables the current autocork behaviour (see C<autocork> 378Enables or disables the current autocork behaviour (see C<autocork>
395constructor argument). 379constructor argument). Changes will only take effect on the next write.
396 380
397=cut 381=cut
382
383sub autocork {
384 $_[0]{autocork} = $_[1];
385}
398 386
399=item $handle->no_delay ($boolean) 387=item $handle->no_delay ($boolean)
400 388
401Enables or disables the C<no_delay> setting (see constructor argument of 389Enables or disables the C<no_delay> setting (see constructor argument of
402the same name for details). 390the same name for details).
495 my ($self, $cb) = @_; 483 my ($self, $cb) = @_;
496 484
497 $self->{on_drain} = $cb; 485 $self->{on_drain} = $cb;
498 486
499 $cb->($self) 487 $cb->($self)
500 if $cb && $self->{low_water_mark} >= length $self->{wbuf}; 488 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
501} 489}
502 490
503=item $handle->push_write ($data) 491=item $handle->push_write ($data)
504 492
505Queues the given scalar to be written. You can push as much data as you 493Queues the given scalar to be written. You can push as much data as you
522 substr $self->{wbuf}, 0, $len, ""; 510 substr $self->{wbuf}, 0, $len, "";
523 511
524 $self->{_activity} = AnyEvent->now; 512 $self->{_activity} = AnyEvent->now;
525 513
526 $self->{on_drain}($self) 514 $self->{on_drain}($self)
527 if $self->{low_water_mark} >= length $self->{wbuf} 515 if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
528 && $self->{on_drain}; 516 && $self->{on_drain};
529 517
530 delete $self->{_ww} unless length $self->{wbuf}; 518 delete $self->{_ww} unless length $self->{wbuf};
531 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) { 519 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
532 $self->_error ($!, 1); 520 $self->_error ($!, 1);
556 544
557 @_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write") 545 @_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
558 ->($self, @_); 546 ->($self, @_);
559 } 547 }
560 548
561 if ($self->{filter_w}) { 549 if ($self->{tls}) {
562 $self->{filter_w}($self, \$_[0]); 550 $self->{_tls_wbuf} .= $_[0];
551
552 &_dotls ($self);
563 } else { 553 } else {
564 $self->{wbuf} .= $_[0]; 554 $self->{wbuf} .= $_[0];
565 $self->_drain_wbuf; 555 $self->_drain_wbuf;
566 } 556 }
567} 557}
584=cut 574=cut
585 575
586register_write_type netstring => sub { 576register_write_type netstring => sub {
587 my ($self, $string) = @_; 577 my ($self, $string) = @_;
588 578
589 sprintf "%d:%s,", (length $string), $string 579 (length $string) . ":$string,"
590}; 580};
591 581
592=item packstring => $format, $data 582=item packstring => $format, $data
593 583
594An octet string prefixed with an encoded length. The encoding C<$format> 584An octet string prefixed with an encoded length. The encoding C<$format>
803 793
804 last; # more data might arrive 794 last; # more data might arrive
805 } 795 }
806 } else { 796 } else {
807 # read side becomes idle 797 # read side becomes idle
808 delete $self->{_rw}; 798 delete $self->{_rw} unless $self->{tls};
809 last; 799 last;
810 } 800 }
811 } 801 }
812 802
813 if ($self->{_eof}) { 803 if ($self->{_eof}) {
1108An octet string prefixed with an encoded length. The encoding C<$format> 1098An octet string prefixed with an encoded length. The encoding C<$format>
1109uses the same format as a Perl C<pack> format, but must specify a single 1099uses the same format as a Perl C<pack> format, but must specify a single
1110integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an 1100integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
1111optional C<!>, C<< < >> or C<< > >> modifier). 1101optional C<!>, C<< < >> or C<< > >> modifier).
1112 1102
1113DNS over TCP uses a prefix of C<n>, EPP uses a prefix of C<N>. 1103For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
1104EPP uses a prefix of C<N> (4 octtes).
1114 1105
1115Example: read a block of data prefixed by its length in BER-encoded 1106Example: read a block of data prefixed by its length in BER-encoded
1116format (very efficient). 1107format (very efficient).
1117 1108
1118 $handle->push_read (packstring => "w", sub { 1109 $handle->push_read (packstring => "w", sub {
1271Note that AnyEvent::Handle will automatically C<start_read> for you when 1262Note that AnyEvent::Handle will automatically C<start_read> for you when
1272you change the C<on_read> callback or push/unshift a read callback, and it 1263you change the C<on_read> callback or push/unshift a read callback, and it
1273will automatically C<stop_read> for you when neither C<on_read> is set nor 1264will automatically C<stop_read> for you when neither C<on_read> is set nor
1274there are any read requests in the queue. 1265there are any read requests in the queue.
1275 1266
1267These methods will have no effect when in TLS mode (as TLS doesn't support
1268half-duplex connections).
1269
1276=cut 1270=cut
1277 1271
1278sub stop_read { 1272sub stop_read {
1279 my ($self) = @_; 1273 my ($self) = @_;
1280 1274
1281 delete $self->{_rw}; 1275 delete $self->{_rw} unless $self->{tls};
1282} 1276}
1283 1277
1284sub start_read { 1278sub start_read {
1285 my ($self) = @_; 1279 my ($self) = @_;
1286 1280
1287 unless ($self->{_rw} || $self->{_eof}) { 1281 unless ($self->{_rw} || $self->{_eof}) {
1288 Scalar::Util::weaken $self; 1282 Scalar::Util::weaken $self;
1289 1283
1290 $self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub { 1284 $self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
1291 my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf}; 1285 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1292 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf; 1286 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
1293 1287
1294 if ($len > 0) { 1288 if ($len > 0) {
1295 $self->{_activity} = AnyEvent->now; 1289 $self->{_activity} = AnyEvent->now;
1296 1290
1297 $self->{filter_r} 1291 if ($self->{tls}) {
1298 ? $self->{filter_r}($self, $rbuf) 1292 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1299 : $self->{_in_drain} || $self->_drain_rbuf; 1293
1294 &_dotls ($self);
1295 } else {
1296 $self->_drain_rbuf unless $self->{_in_drain};
1297 }
1300 1298
1301 } elsif (defined $len) { 1299 } elsif (defined $len) {
1302 delete $self->{_rw}; 1300 delete $self->{_rw};
1303 $self->{_eof} = 1; 1301 $self->{_eof} = 1;
1304 $self->_drain_rbuf unless $self->{_in_drain}; 1302 $self->_drain_rbuf unless $self->{_in_drain};
1308 } 1306 }
1309 }); 1307 });
1310 } 1308 }
1311} 1309}
1312 1310
1311# poll the write BIO and send the data if applicable
1313sub _dotls { 1312sub _dotls {
1314 my ($self) = @_; 1313 my ($self) = @_;
1315 1314
1316 my $buf; 1315 my $tmp;
1317 1316
1318 if (length $self->{_tls_wbuf}) { 1317 if (length $self->{_tls_wbuf}) {
1319 while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) { 1318 while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
1320 substr $self->{_tls_wbuf}, 0, $len, ""; 1319 substr $self->{_tls_wbuf}, 0, $tmp, "";
1321 } 1320 }
1322 } 1321 }
1323 1322
1324 if (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1325 $self->{wbuf} .= $buf;
1326 $self->_drain_wbuf;
1327 }
1328
1329 while (defined ($buf = Net::SSLeay::read ($self->{tls}))) { 1323 while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
1330 if (length $buf) { 1324 unless (length $tmp) {
1331 $self->{rbuf} .= $buf;
1332 $self->_drain_rbuf unless $self->{_in_drain};
1333 } else {
1334 # let's treat SSL-eof as we treat normal EOF 1325 # let's treat SSL-eof as we treat normal EOF
1326 delete $self->{_rw};
1335 $self->{_eof} = 1; 1327 $self->{_eof} = 1;
1336 $self->_shutdown; 1328 &_freetls;
1337 return;
1338 } 1329 }
1339 }
1340 1330
1331 $self->{rbuf} .= $tmp;
1332 $self->_drain_rbuf unless $self->{_in_drain};
1333 $self->{tls} or return; # tls session might have gone away in callback
1334 }
1335
1341 my $err = Net::SSLeay::get_error ($self->{tls}, -1); 1336 $tmp = Net::SSLeay::get_error ($self->{tls}, -1);
1342 1337
1343 if ($err!= Net::SSLeay::ERROR_WANT_READ ()) { 1338 if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
1344 if ($err == Net::SSLeay::ERROR_SYSCALL ()) { 1339 if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
1345 return $self->_error ($!, 1); 1340 return $self->_error ($!, 1);
1346 } elsif ($err == Net::SSLeay::ERROR_SSL ()) { 1341 } elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
1347 return $self->_error (&Errno::EIO, 1); 1342 return $self->_error (&Errno::EIO, 1);
1348 } 1343 }
1349 1344
1350 # all others are fine for our purposes 1345 # all other errors are fine for our purposes
1346 }
1347
1348 while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1349 $self->{wbuf} .= $tmp;
1350 $self->_drain_wbuf;
1351 } 1351 }
1352} 1352}
1353 1353
1354=item $handle->starttls ($tls[, $tls_ctx]) 1354=item $handle->starttls ($tls[, $tls_ctx])
1355 1355
1365 1365
1366The TLS connection object will end up in C<< $handle->{tls} >> after this 1366The TLS connection object will end up in C<< $handle->{tls} >> after this
1367call and can be used or changed to your liking. Note that the handshake 1367call and can be used or changed to your liking. Note that the handshake
1368might have already started when this function returns. 1368might have already started when this function returns.
1369 1369
1370If it an error to start a TLS handshake more than once per
1371AnyEvent::Handle object (this is due to bugs in OpenSSL).
1372
1370=cut 1373=cut
1371 1374
1372sub starttls { 1375sub starttls {
1373 my ($self, $ssl, $ctx) = @_; 1376 my ($self, $ssl, $ctx) = @_;
1374 1377
1375 $self->stoptls; 1378 require Net::SSLeay;
1376 1379
1380 Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
1381 if $self->{tls};
1382
1377 if ($ssl eq "accept") { 1383 if ($ssl eq "accept") {
1378 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1384 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
1379 Net::SSLeay::set_accept_state ($ssl); 1385 Net::SSLeay::set_accept_state ($ssl);
1380 } elsif ($ssl eq "connect") { 1386 } elsif ($ssl eq "connect") {
1381 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1387 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
1390 # and mismaintained ssleay-module doesn't even offer them). 1396 # and mismaintained ssleay-module doesn't even offer them).
1391 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html 1397 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
1392 # 1398 #
1393 # in short: this is a mess. 1399 # in short: this is a mess.
1394 # 1400 #
1395 # note that we do not try to kepe the length constant between writes as we are required to do. 1401 # note that we do not try to keep the length constant between writes as we are required to do.
1396 # we assume that most (but not all) of this insanity only applies to non-blocking cases, 1402 # we assume that most (but not all) of this insanity only applies to non-blocking cases,
1397 # and we drive openssl fully in blocking mode here. 1403 # and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
1404 # have identity issues in that area.
1398 Net::SSLeay::CTX_set_mode ($self->{tls}, 1405 Net::SSLeay::CTX_set_mode ($self->{tls},
1399 (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1) 1406 (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
1400 | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2)); 1407 | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
1401 1408
1402 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 1409 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1403 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 1410 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1404 1411
1405 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio}); 1412 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
1406 1413
1407 $self->{filter_w} = sub { 1414 &_dotls; # need to trigger the initial handshake
1408 $_[0]{_tls_wbuf} .= ${$_[1]}; 1415 $self->start_read; # make sure we actually do read
1409 &_dotls;
1410 };
1411 $self->{filter_r} = sub {
1412 Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
1413 &_dotls;
1414 };
1415} 1416}
1416 1417
1417=item $handle->stoptls 1418=item $handle->stoptls
1418 1419
1419Destroys the SSL connection, if any. Partial read or write data will be 1420Shuts down the SSL connection - this makes a proper EOF handshake by
1420lost. 1421sending a close notify to the other side, but since OpenSSL doesn't
1422support non-blocking shut downs, it is not possible to re-use the stream
1423afterwards.
1421 1424
1422=cut 1425=cut
1423 1426
1424sub stoptls { 1427sub stoptls {
1425 my ($self) = @_; 1428 my ($self) = @_;
1426 1429
1430 if ($self->{tls}) {
1431 Net::SSLeay::shutdown ($self->{tls});
1432
1433 &_dotls;
1434
1435 # we don't give a shit. no, we do, but we can't. no...
1436 # we, we... have to use openssl :/
1437 &_freetls;
1438 }
1439}
1440
1441sub _freetls {
1442 my ($self) = @_;
1443
1444 return unless $self->{tls};
1445
1427 Net::SSLeay::free (delete $self->{tls}) if $self->{tls}; 1446 Net::SSLeay::free (delete $self->{tls});
1428 1447
1429 delete $self->{_rbio}; 1448 delete @$self{qw(_rbio _wbio _tls_wbuf)};
1430 delete $self->{_wbio};
1431 delete $self->{_tls_wbuf};
1432 delete $self->{filter_r};
1433 delete $self->{filter_w};
1434} 1449}
1435 1450
1436sub DESTROY { 1451sub DESTROY {
1437 my $self = shift; 1452 my $self = shift;
1438 1453
1439 $self->stoptls; 1454 &_freetls;
1440 1455
1441 my $linger = exists $self->{linger} ? $self->{linger} : 3600; 1456 my $linger = exists $self->{linger} ? $self->{linger} : 3600;
1442 1457
1443 if ($linger && length $self->{wbuf}) { 1458 if ($linger && length $self->{wbuf}) {
1444 my $fh = delete $self->{fh}; 1459 my $fh = delete $self->{fh};
1459 @linger = (); 1474 @linger = ();
1460 }); 1475 });
1461 } 1476 }
1462} 1477}
1463 1478
1479=item $handle->destroy
1480
1481Shuts down the handle object as much as possible - this call ensures that
1482no further callbacks will be invoked and resources will be freed as much
1483as possible. You must not call any methods on the object afterwards.
1484
1485Normally, you can just "forget" any references to an AnyEvent::Handle
1486object and it will simply shut down. This works in fatal error and EOF
1487callbacks, as well as code outside. It does I<NOT> work in a read or write
1488callback, so when you want to destroy the AnyEvent::Handle object from
1489within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
1490that case.
1491
1492The handle might still linger in the background and write out remaining
1493data, as specified by the C<linger> option, however.
1494
1495=cut
1496
1497sub destroy {
1498 my ($self) = @_;
1499
1500 $self->DESTROY;
1501 %$self = ();
1502}
1503
1464=item AnyEvent::Handle::TLS_CTX 1504=item AnyEvent::Handle::TLS_CTX
1465 1505
1466This function creates and returns the Net::SSLeay::CTX object used by 1506This function creates and returns the Net::SSLeay::CTX object used by
1467default for TLS mode. 1507default for TLS mode.
1468 1508
1496 } 1536 }
1497} 1537}
1498 1538
1499=back 1539=back
1500 1540
1541
1542=head1 NONFREQUENTLY ASKED QUESTIONS
1543
1544=over 4
1545
1546=item I C<undef> the AnyEvent::Handle reference inside my callback and
1547still get further invocations!
1548
1549That's because AnyEvent::Handle keeps a reference to itself when handling
1550read or write callbacks.
1551
1552It is only safe to "forget" the reference inside EOF or error callbacks,
1553from within all other callbacks, you need to explicitly call the C<<
1554->destroy >> method.
1555
1556=item I get different callback invocations in TLS mode/Why can't I pause
1557reading?
1558
1559Unlike, say, TCP, TLS connections do not consist of two independent
1560communication channels, one for each direction. Or put differently. The
1561read and write directions are not independent of each other: you cannot
1562write data unless you are also prepared to read, and vice versa.
1563
1564This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
1565callback invocations when you are not expecting any read data - the reason
1566is that AnyEvent::Handle always reads in TLS mode.
1567
1568During the connection, you have to make sure that you always have a
1569non-empty read-queue, or an C<on_read> watcher. At the end of the
1570connection (or when you no longer want to use it) you can call the
1571C<destroy> method.
1572
1573=item How do I read data until the other side closes the connection?
1574
1575If you just want to read your data into a perl scalar, the easiest way
1576to achieve this is by setting an C<on_read> callback that does nothing,
1577clearing the C<on_eof> callback and in the C<on_error> callback, the data
1578will be in C<$_[0]{rbuf}>:
1579
1580 $handle->on_read (sub { });
1581 $handle->on_eof (undef);
1582 $handle->on_error (sub {
1583 my $data = delete $_[0]{rbuf};
1584 undef $handle;
1585 });
1586
1587The reason to use C<on_error> is that TCP connections, due to latencies
1588and packets loss, might get closed quite violently with an error, when in
1589fact, all data has been received.
1590
1591It is usually better to use acknowledgements when transferring data,
1592to make sure the other side hasn't just died and you got the data
1593intact. This is also one reason why so many internet protocols have an
1594explicit QUIT command.
1595
1596=item I don't want to destroy the handle too early - how do I wait until
1597all data has been written?
1598
1599After writing your last bits of data, set the C<on_drain> callback
1600and destroy the handle in there - with the default setting of
1601C<low_water_mark> this will be called precisely when all data has been
1602written to the socket:
1603
1604 $handle->push_write (...);
1605 $handle->on_drain (sub {
1606 warn "all data submitted to the kernel\n";
1607 undef $handle;
1608 });
1609
1610=back
1611
1612
1501=head1 SUBCLASSING AnyEvent::Handle 1613=head1 SUBCLASSING AnyEvent::Handle
1502 1614
1503In many cases, you might want to subclass AnyEvent::Handle. 1615In many cases, you might want to subclass AnyEvent::Handle.
1504 1616
1505To make this easier, a given version of AnyEvent::Handle uses these 1617To make this easier, a given version of AnyEvent::Handle uses these

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