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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.100 by root, Thu Oct 23 02:44:50 2008 UTC vs.
Revision 1.132 by elmex, Thu Jul 2 22:25:13 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 = 4.3; 19our $VERSION = 4.45;
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");
63 63
64=head1 METHODS 64=head1 METHODS
65 65
66=over 4 66=over 4
67 67
68=item B<new (%args)> 68=item $handle = B<new> AnyEvent::TLS fh => $filehandle, key => value...
69 69
70The constructor supports these arguments (all as key => value pairs). 70The constructor supports these arguments (all as C<< key => value >> pairs).
71 71
72=over 4 72=over 4
73 73
74=item fh => $filehandle [MANDATORY] 74=item fh => $filehandle [MANDATORY]
75 75
84Set the callback to be called when an end-of-file condition is detected, 84Set the callback to be called when an end-of-file condition is detected,
85i.e. in the case of a socket, when the other side has closed the 85i.e. in the case of a socket, when the other side has closed the
86connection cleanly. 86connection cleanly.
87 87
88For sockets, this just means that the other side has stopped sending data, 88For sockets, this just means that the other side has stopped sending data,
89you can still try to write data, and, in fact, one can return from the eof 89you can still try to write data, and, in fact, one can return from the EOF
90callback and continue writing data, as only the read part has been shut 90callback and continue writing data, as only the read part has been shut
91down. 91down.
92 92
93While not mandatory, it is I<highly> recommended to set an eof callback, 93While not mandatory, it is I<highly> recommended to set an EOF callback,
94otherwise you might end up with a closed socket while you are still 94otherwise you might end up with a closed socket while you are still
95waiting for data. 95waiting for data.
96 96
97If an EOF condition has been detected but no C<on_eof> callback has been 97If an EOF condition has been detected but no C<on_eof> callback has been
98set, then a fatal error will be raised with C<$!> set to <0>. 98set, then a fatal error will be raised with C<$!> set to <0>.
127and no read request is in the queue (unlike read queue callbacks, this 127and no read request is in the queue (unlike read queue callbacks, this
128callback will only be called when at least one octet of data is in the 128callback will only be called when at least one octet of data is in the
129read buffer). 129read buffer).
130 130
131To access (and remove data from) the read buffer, use the C<< ->rbuf >> 131To access (and remove data from) the read buffer, use the C<< ->rbuf >>
132method or access the C<$handle->{rbuf}> member directly. 132method or access the C<$handle->{rbuf}> member directly. Note that you
133must not enlarge or modify the read buffer, you can only remove data at
134the beginning from it.
133 135
134When an EOF condition is detected then AnyEvent::Handle will first try to 136When an EOF condition is detected then AnyEvent::Handle will first try to
135feed all the remaining data to the queued callbacks and C<on_read> before 137feed all the remaining data to the queued callbacks and C<on_read> before
136calling the C<on_eof> callback. If no progress can be made, then a fatal 138calling the C<on_eof> callback. If no progress can be made, then a fatal
137error will be raised (with C<$!> set to C<EPIPE>). 139error will be raised (with C<$!> set to C<EPIPE>).
235 237
236This will not work for partial TLS data that could not be encoded 238This 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 239yet. This data will be lost. Calling the C<stoptls> method in time might
238help. 240help.
239 241
242=item common_name => $string
243
244The common name used by some verification methods (most notably SSL/TLS)
245associated with this connection. Usually this is the remote hostname used
246to connect, but can be almost anything.
247
240=item tls => "accept" | "connect" | Net::SSLeay::SSL object 248=item tls => "accept" | "connect" | Net::SSLeay::SSL object
241 249
242When this parameter is given, it enables TLS (SSL) mode, that means 250When this parameter is given, it enables TLS (SSL) mode, that means
243AnyEvent will start a TLS handshake as soon as the conenction has been 251AnyEvent will start a TLS handshake as soon as the conenction has been
244established and will transparently encrypt/decrypt data afterwards. 252established and will transparently encrypt/decrypt data afterwards.
253mode. 261mode.
254 262
255You can also provide your own TLS connection object, but you have 263You can also provide your own TLS connection object, but you have
256to make sure that you call either C<Net::SSLeay::set_connect_state> 264to make sure that you call either C<Net::SSLeay::set_connect_state>
257or C<Net::SSLeay::set_accept_state> on it before you pass it to 265or C<Net::SSLeay::set_accept_state> on it before you pass it to
258AnyEvent::Handle. 266AnyEvent::Handle. Also, this module will take ownership of this connection
267object.
268
269At some future point, AnyEvent::Handle might switch to another TLS
270implementation, then the option to use your own session object will go
271away.
272
273B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
274passing in the wrong integer will lead to certain crash. This most often
275happens when one uses a stylish C<< tls => 1 >> and is surprised about the
276segmentation fault.
259 277
260See the C<< ->starttls >> method for when need to start TLS negotiation later. 278See the C<< ->starttls >> method for when need to start TLS negotiation later.
261 279
262=item tls_ctx => $ssl_ctx 280=item tls_ctx => $anyevent_tls
263 281
264Use the given C<Net::SSLeay::CTX> object to create the new TLS connection 282Use the given C<AnyEvent::TLS> object to create the new TLS connection
265(unless a connection object was specified directly). If this parameter is 283(unless a connection object was specified directly). If this parameter is
266missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>. 284missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
285
286Instead of an object, you can also specify a hash reference with C<< key
287=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
288new TLS context object.
267 289
268=item json => JSON or JSON::XS object 290=item json => JSON or JSON::XS object
269 291
270This is the json coder object used by the C<json> read and write types. 292This is the json coder object used by the C<json> read and write types.
271 293
280 302
281=cut 303=cut
282 304
283sub new { 305sub new {
284 my $class = shift; 306 my $class = shift;
285
286 my $self = bless { @_ }, $class; 307 my $self = bless { @_ }, $class;
287 308
288 $self->{fh} or Carp::croak "mandatory argument fh is missing"; 309 $self->{fh} or Carp::croak "mandatory argument fh is missing";
289 310
290 AnyEvent::Util::fh_nonblocking $self->{fh}, 1; 311 AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
312
313 $self->{_activity} = AnyEvent->now;
314 $self->_timeout;
315
316 $self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
291 317
292 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx}) 318 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
293 if $self->{tls}; 319 if $self->{tls};
294 320
295 $self->{_activity} = AnyEvent->now;
296 $self->_timeout;
297
298 $self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain}; 321 $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};
300 322
301 $self->start_read 323 $self->start_read
302 if $self->{on_read}; 324 if $self->{on_read};
303 325
304 $self 326 $self->{fh} && $self
305} 327}
306 328
307sub _shutdown { 329sub _shutdown {
308 my ($self) = @_; 330 my ($self) = @_;
309 331
310 delete $self->{_tw}; 332 delete @$self{qw(_tw _rw _ww fh wbuf on_read _queue)};
311 delete $self->{_rw}; 333 $self->{_eof} = 1; # tell starttls et. al to stop trying
312 delete $self->{_ww};
313 delete $self->{fh};
314 334
315 &_freetls; 335 &_freetls;
316
317 delete $self->{on_read};
318 delete $self->{_queue};
319} 336}
320 337
321sub _error { 338sub _error {
322 my ($self, $errno, $fatal) = @_; 339 my ($self, $errno, $fatal) = @_;
323 340
374} 391}
375 392
376=item $handle->autocork ($boolean) 393=item $handle->autocork ($boolean)
377 394
378Enables or disables the current autocork behaviour (see C<autocork> 395Enables or disables the current autocork behaviour (see C<autocork>
379constructor argument). 396constructor argument). Changes will only take effect on the next write.
380 397
381=cut 398=cut
399
400sub autocork {
401 $_[0]{autocork} = $_[1];
402}
382 403
383=item $handle->no_delay ($boolean) 404=item $handle->no_delay ($boolean)
384 405
385Enables or disables the C<no_delay> setting (see constructor argument of 406Enables or disables the C<no_delay> setting (see constructor argument of
386the same name for details). 407the same name for details).
758 ) { 779 ) {
759 $self->_error (&Errno::ENOSPC, 1), return; 780 $self->_error (&Errno::ENOSPC, 1), return;
760 } 781 }
761 782
762 while () { 783 while () {
784 # we need to use a separate tls read buffer, as we must not receive data while
785 # we are draining the buffer, and this can only happen with TLS.
786 $self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
787
763 my $len = length $self->{rbuf}; 788 my $len = length $self->{rbuf};
764 789
765 if (my $cb = shift @{ $self->{_queue} }) { 790 if (my $cb = shift @{ $self->{_queue} }) {
766 unless ($cb->($self)) { 791 unless ($cb->($self)) {
767 if ($self->{_eof}) { 792 if ($self->{_eof}) {
828 853
829=item $handle->rbuf 854=item $handle->rbuf
830 855
831Returns the read buffer (as a modifiable lvalue). 856Returns the read buffer (as a modifiable lvalue).
832 857
833You can access the read buffer directly as the C<< ->{rbuf} >> member, if 858You can access the read buffer directly as the C<< ->{rbuf} >>
834you want. 859member, if you want. However, the only operation allowed on the
860read buffer (apart from looking at it) is removing data from its
861beginning. Otherwise modifying or appending to it is not allowed and will
862lead to hard-to-track-down bugs.
835 863
836NOTE: The read buffer should only be used or modified if the C<on_read>, 864NOTE: The read buffer should only be used or modified if the C<on_read>,
837C<push_read> or C<unshift_read> methods are used. The other read methods 865C<push_read> or C<unshift_read> methods are used. The other read methods
838automatically manage the read buffer. 866automatically manage the read buffer.
839 867
1135 } 1163 }
1136}; 1164};
1137 1165
1138=item json => $cb->($handle, $hash_or_arrayref) 1166=item json => $cb->($handle, $hash_or_arrayref)
1139 1167
1140Reads a JSON object or array, decodes it and passes it to the callback. 1168Reads a JSON object or array, decodes it and passes it to the
1169callback. When a parse error occurs, an C<EBADMSG> error will be raised.
1141 1170
1142If a C<json> object was passed to the constructor, then that will be used 1171If a C<json> object was passed to the constructor, then that will be used
1143for the final decode, otherwise it will create a JSON coder expecting UTF-8. 1172for the final decode, otherwise it will create a JSON coder expecting UTF-8.
1144 1173
1145This read type uses the incremental parser available with JSON version 1174This read type uses the incremental parser available with JSON version
1162 my $rbuf = \$self->{rbuf}; 1191 my $rbuf = \$self->{rbuf};
1163 1192
1164 my $json = $self->{json} ||= JSON->new->utf8; 1193 my $json = $self->{json} ||= JSON->new->utf8;
1165 1194
1166 sub { 1195 sub {
1167 my $ref = $json->incr_parse ($self->{rbuf}); 1196 my $ref = eval { $json->incr_parse ($self->{rbuf}) };
1168 1197
1169 if ($ref) { 1198 if ($ref) {
1170 $self->{rbuf} = $json->incr_text; 1199 $self->{rbuf} = $json->incr_text;
1171 $json->incr_text = ""; 1200 $json->incr_text = "";
1172 $cb->($self, $ref); 1201 $cb->($self, $ref);
1173 1202
1174 1 1203 1
1204 } elsif ($@) {
1205 # error case
1206 $json->incr_skip;
1207
1208 $self->{rbuf} = $json->incr_text;
1209 $json->incr_text = "";
1210
1211 $self->_error (&Errno::EBADMSG);
1212
1213 ()
1175 } else { 1214 } else {
1176 $self->{rbuf} = ""; 1215 $self->{rbuf} = "";
1216
1177 () 1217 ()
1178 } 1218 }
1179 } 1219 }
1180}; 1220};
1181 1221
1322 delete $self->{_rw}; 1362 delete $self->{_rw};
1323 $self->{_eof} = 1; 1363 $self->{_eof} = 1;
1324 &_freetls; 1364 &_freetls;
1325 } 1365 }
1326 1366
1327 $self->{rbuf} .= $tmp; 1367 $self->{_tls_rbuf} .= $tmp;
1328 $self->_drain_rbuf unless $self->{_in_drain}; 1368 $self->_drain_rbuf unless $self->{_in_drain};
1329 $self->{tls} or return; # tls session might have gone away in callback 1369 $self->{tls} or return; # tls session might have gone away in callback
1330 } 1370 }
1331 1371
1332 $tmp = Net::SSLeay::get_error ($self->{tls}, -1); 1372 $tmp = Net::SSLeay::get_error ($self->{tls}, -1);
1333 1373
1334 if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) { 1374 if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
1335 if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) { 1375 if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
1336 return $self->_error ($!, 1); 1376 return $self->_error ($!, 1);
1337 } elsif ($tmp == Net::SSLeay::ERROR_SSL ()) { 1377 } elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
1338 return $self->_error (&Errno::EIO, 1); 1378 return $self->_error (&Errno::EIO, 1);
1339 } 1379 }
1340 1380
1341 # all other errors are fine for our purposes 1381 # all other errors are fine for our purposes
1342 } 1382 }
1354C<starttls>. 1394C<starttls>.
1355 1395
1356The first argument is the same as the C<tls> constructor argument (either 1396The first argument is the same as the C<tls> constructor argument (either
1357C<"connect">, C<"accept"> or an existing Net::SSLeay object). 1397C<"connect">, C<"accept"> or an existing Net::SSLeay object).
1358 1398
1359The second argument is the optional C<Net::SSLeay::CTX> object that is 1399The second argument is the optional C<AnyEvent::TLS> object that is used
1360used when AnyEvent::Handle has to create its own TLS connection object. 1400when AnyEvent::Handle has to create its own TLS connection object, or
1401a hash reference with C<< key => value >> pairs that will be used to
1402construct a new context.
1361 1403
1362The TLS connection object will end up in C<< $handle->{tls} >> after this 1404The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
1363call and can be used or changed to your liking. Note that the handshake 1405context in C<< $handle->{tls_ctx} >> after this call and can be used or
1364might have already started when this function returns. 1406changed to your liking. Note that the handshake might have already started
1407when this function returns.
1365 1408
1366If it an error to start a TLS handshake more than once per 1409If it an error to start a TLS handshake more than once per
1367AnyEvent::Handle object (this is due to bugs in OpenSSL). 1410AnyEvent::Handle object (this is due to bugs in OpenSSL).
1368 1411
1369=cut 1412=cut
1371sub starttls { 1414sub starttls {
1372 my ($self, $ssl, $ctx) = @_; 1415 my ($self, $ssl, $ctx) = @_;
1373 1416
1374 require Net::SSLeay; 1417 require Net::SSLeay;
1375 1418
1376 Carp::croak "it is an error to call starttls more than once on an Anyevent::Handle object" 1419 Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
1377 if $self->{tls}; 1420 if $self->{tls};
1421
1422 $ctx ||= $self->{tls_ctx};
1423
1424 if ("HASH" eq ref $ctx) {
1425 require AnyEvent::TLS;
1426
1427 local $Carp::CarpLevel = 1; # skip ourselves when creating a new context
1428 $ctx = new AnyEvent::TLS %$ctx;
1429 }
1378 1430
1379 if ($ssl eq "accept") { 1431 $self->{tls_ctx} = $ctx || TLS_CTX ();
1380 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1432 $self->{tls} = $ssl = $self->{tls_ctx}->_get_session ($ssl, $self);
1381 Net::SSLeay::set_accept_state ($ssl);
1382 } elsif ($ssl eq "connect") {
1383 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
1384 Net::SSLeay::set_connect_state ($ssl);
1385 }
1386
1387 $self->{tls} = $ssl;
1388 1433
1389 # basically, this is deep magic (because SSL_read should have the same issues) 1434 # basically, this is deep magic (because SSL_read should have the same issues)
1390 # but the openssl maintainers basically said: "trust us, it just works". 1435 # but the openssl maintainers basically said: "trust us, it just works".
1391 # (unfortunately, we have to hardcode constants because the abysmally misdesigned 1436 # (unfortunately, we have to hardcode constants because the abysmally misdesigned
1392 # and mismaintained ssleay-module doesn't even offer them). 1437 # and mismaintained ssleay-module doesn't even offer them).
1396 # 1441 #
1397 # note that we do not try to keep the length constant between writes as we are required to do. 1442 # note that we do not try to keep the length constant between writes as we are required to do.
1398 # we assume that most (but not all) of this insanity only applies to non-blocking cases, 1443 # we assume that most (but not all) of this insanity only applies to non-blocking cases,
1399 # and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to 1444 # and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
1400 # have identity issues in that area. 1445 # have identity issues in that area.
1401 Net::SSLeay::CTX_set_mode ($self->{tls}, 1446# Net::SSLeay::CTX_set_mode ($ssl,
1402 (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1) 1447# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
1403 | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2)); 1448# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
1449 Net::SSLeay::CTX_set_mode ($ssl, 1|2);
1404 1450
1405 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 1451 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1406 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 1452 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1407 1453
1408 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio}); 1454 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
1437sub _freetls { 1483sub _freetls {
1438 my ($self) = @_; 1484 my ($self) = @_;
1439 1485
1440 return unless $self->{tls}; 1486 return unless $self->{tls};
1441 1487
1442 Net::SSLeay::free (delete $self->{tls}); 1488 $self->{tls_ctx}->_put_session (delete $self->{tls});
1443 1489
1444 delete @$self{qw(_rbio _wbio _tls_wbuf)}; 1490 delete @$self{qw(_rbio _wbio _tls_wbuf)};
1445} 1491}
1446 1492
1447sub DESTROY { 1493sub DESTROY {
1448 my $self = shift; 1494 my ($self) = @_;
1449 1495
1450 &_freetls; 1496 &_freetls;
1451 1497
1452 my $linger = exists $self->{linger} ? $self->{linger} : 3600; 1498 my $linger = exists $self->{linger} ? $self->{linger} : 3600;
1453 1499
1472 } 1518 }
1473} 1519}
1474 1520
1475=item $handle->destroy 1521=item $handle->destroy
1476 1522
1477Shut's down the handle object as much as possible - this call ensures that 1523Shuts down the handle object as much as possible - this call ensures that
1478no further callbacks will be invoked and resources will be freed as much 1524no further callbacks will be invoked and resources will be freed as much
1479as possible. You must not call any methods on the object afterwards. 1525as possible. You must not call any methods on the object afterwards.
1480 1526
1527Normally, you can just "forget" any references to an AnyEvent::Handle
1528object and it will simply shut down. This works in fatal error and EOF
1529callbacks, as well as code outside. It does I<NOT> work in a read or write
1530callback, so when you want to destroy the AnyEvent::Handle object from
1531within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
1532that case.
1533
1481The handle might still linger in the background and write out remaining 1534The handle might still linger in the background and write out remaining
1482data, as specified by the C<linger> option, however. 1535data, as specified by the C<linger> option, however.
1483 1536
1484=cut 1537=cut
1485 1538
1490 %$self = (); 1543 %$self = ();
1491} 1544}
1492 1545
1493=item AnyEvent::Handle::TLS_CTX 1546=item AnyEvent::Handle::TLS_CTX
1494 1547
1495This function creates and returns the Net::SSLeay::CTX object used by 1548This function creates and returns the AnyEvent::TLS object used by default
1496default for TLS mode. 1549for TLS mode.
1497 1550
1498The context is created like this: 1551The context is created by calling L<AnyEvent::TLS> without any arguments.
1499
1500 Net::SSLeay::load_error_strings;
1501 Net::SSLeay::SSLeay_add_ssl_algorithms;
1502 Net::SSLeay::randomize;
1503
1504 my $CTX = Net::SSLeay::CTX_new;
1505
1506 Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
1507 1552
1508=cut 1553=cut
1509 1554
1510our $TLS_CTX; 1555our $TLS_CTX;
1511 1556
1512sub TLS_CTX() { 1557sub TLS_CTX() {
1513 $TLS_CTX || do { 1558 $TLS_CTX ||= do {
1514 require Net::SSLeay; 1559 require AnyEvent::TLS;
1515 1560
1516 Net::SSLeay::load_error_strings (); 1561 new AnyEvent::TLS
1517 Net::SSLeay::SSLeay_add_ssl_algorithms ();
1518 Net::SSLeay::randomize ();
1519
1520 $TLS_CTX = Net::SSLeay::CTX_new ();
1521
1522 Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
1523
1524 $TLS_CTX
1525 } 1562 }
1526} 1563}
1527 1564
1528=back 1565=back
1529 1566
1530 1567
1531=head1 NONFREQUENTLY ASKED QUESTIONS 1568=head1 NONFREQUENTLY ASKED QUESTIONS
1532 1569
1533=over 4 1570=over 4
1571
1572=item I C<undef> the AnyEvent::Handle reference inside my callback and
1573still get further invocations!
1574
1575That's because AnyEvent::Handle keeps a reference to itself when handling
1576read or write callbacks.
1577
1578It is only safe to "forget" the reference inside EOF or error callbacks,
1579from within all other callbacks, you need to explicitly call the C<<
1580->destroy >> method.
1581
1582=item I get different callback invocations in TLS mode/Why can't I pause
1583reading?
1584
1585Unlike, say, TCP, TLS connections do not consist of two independent
1586communication channels, one for each direction. Or put differently. The
1587read and write directions are not independent of each other: you cannot
1588write data unless you are also prepared to read, and vice versa.
1589
1590This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
1591callback invocations when you are not expecting any read data - the reason
1592is that AnyEvent::Handle always reads in TLS mode.
1593
1594During the connection, you have to make sure that you always have a
1595non-empty read-queue, or an C<on_read> watcher. At the end of the
1596connection (or when you no longer want to use it) you can call the
1597C<destroy> method.
1534 1598
1535=item How do I read data until the other side closes the connection? 1599=item How do I read data until the other side closes the connection?
1536 1600
1537If you just want to read your data into a perl scalar, the easiest way 1601If 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, 1602to achieve this is by setting an C<on_read> callback that does nothing,
1548 1612
1549The reason to use C<on_error> is that TCP connections, due to latencies 1613The 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 1614and packets loss, might get closed quite violently with an error, when in
1551fact, all data has been received. 1615fact, all data has been received.
1552 1616
1553It is usually better to use acknowledgements when transfering data, 1617It is usually better to use acknowledgements when transferring data,
1554to make sure the other side hasn't just died and you got the data 1618to 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 1619intact. This is also one reason why so many internet protocols have an
1556explicit QUIT command. 1620explicit QUIT command.
1557
1558 1621
1559=item I don't want to destroy the handle too early - how do I wait until 1622=item I don't want to destroy the handle too early - how do I wait until
1560all data has been written? 1623all data has been written?
1561 1624
1562After writing your last bits of data, set the C<on_drain> callback 1625After writing your last bits of data, set the C<on_drain> callback
1568 $handle->on_drain (sub { 1631 $handle->on_drain (sub {
1569 warn "all data submitted to the kernel\n"; 1632 warn "all data submitted to the kernel\n";
1570 undef $handle; 1633 undef $handle;
1571 }); 1634 });
1572 1635
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 1636=back
1591 1637
1592 1638
1593=head1 SUBCLASSING AnyEvent::Handle 1639=head1 SUBCLASSING AnyEvent::Handle
1594 1640

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