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Revision 1.188 by root, Thu Sep 17 08:20:14 2009 UTC vs.
Revision 1.210 by root, Thu Dec 30 01:53:15 2010 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent 3AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use AnyEvent; 7 use AnyEvent;
8 use AnyEvent::Handle; 8 use AnyEvent::Handle;
… …
30 30
31 $cv->recv; 31 $cv->recv;
32 32
33=head1 DESCRIPTION 33=head1 DESCRIPTION
34 34
35This module is a helper module to make it easier to do event-based I/O on 35This is a helper module to make it easier to do event-based I/O on
36filehandles. 36stream-based filehandles (sockets, pipes, and other stream things).
37 37
38The L<AnyEvent::Intro> tutorial contains some well-documented 38The L<AnyEvent::Intro> tutorial contains some well-documented
39AnyEvent::Handle examples. 39AnyEvent::Handle examples.
40 40
41In the following, when the documentation refers to of "bytes" then this 41In the following, where the documentation refers to "bytes", it means
42means characters. As sysread and syswrite are used for all I/O, their 42characters. As sysread and syswrite are used for all I/O, their
43treatment of characters applies to this module as well. 43treatment of characters applies to this module as well.
44 44
45At the very minimum, you should specify C<fh> or C<connect>, and the 45At the very minimum, you should specify C<fh> or C<connect>, and the
46C<on_error> callback. 46C<on_error> callback.
47 47
… …
75 } 75 }
76 76
77 \&$func 77 \&$func
78} 78}
79 79
80sub MAX_READ_SIZE() { 131072 }
81
80=head1 METHODS 82=head1 METHODS
81 83
82=over 4 84=over 4
83 85
84=item $handle = B<new> AnyEvent::TLS fh => $filehandle, key => value... 86=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
85 87
86The constructor supports these arguments (all as C<< key => value >> pairs). 88The constructor supports these arguments (all as C<< key => value >> pairs).
87 89
88=over 4 90=over 4
89 91
… …
112=over 4 114=over 4
113 115
114=item on_prepare => $cb->($handle) 116=item on_prepare => $cb->($handle)
115 117
116This (rarely used) callback is called before a new connection is 118This (rarely used) callback is called before a new connection is
117attempted, but after the file handle has been created. It could be used to 119attempted, but after the file handle has been created (you can access that
120file handle via C<< $handle->{fh} >>). It could be used to prepare the
118prepare the file handle with parameters required for the actual connect 121file handle with parameters required for the actual connect (as opposed to
119(as opposed to settings that can be changed when the connection is already 122settings that can be changed when the connection is already established).
120established).
121 123
122The return value of this callback should be the connect timeout value in 124The return value of this callback should be the connect timeout value in
123seconds (or C<0>, or C<undef>, or the empty list, to indicate the default 125seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
124timeout is to be used). 126default timeout is to be used).
125 127
126=item on_connect => $cb->($handle, $host, $port, $retry->()) 128=item on_connect => $cb->($handle, $host, $port, $retry->())
127 129
128This callback is called when a connection has been successfully established. 130This callback is called when a connection has been successfully established.
129 131
130The actual numeric host and port (the socket peername) are passed as 132The peer's numeric host and port (the socket peername) are passed as
131parameters, together with a retry callback. 133parameters, together with a retry callback.
132 134
133When, for some reason, the handle is not acceptable, then calling 135If, for some reason, the handle is not acceptable, calling C<$retry>
134C<$retry> will continue with the next connection target (in case of 136will continue with the next connection target (in case of multi-homed
135multi-homed hosts or SRV records there can be multiple connection 137hosts or SRV records there can be multiple connection endpoints). At the
136endpoints). At the time it is called the read and write queues, eof 138time it is called the read and write queues, eof status, tls status and
137status, tls status and similar properties of the handle will have been 139similar properties of the handle will have been reset.
138reset.
139 140
140In most cases, ignoring the C<$retry> parameter is the way to go. 141In most cases, you should ignore the C<$retry> parameter.
141 142
142=item on_connect_error => $cb->($handle, $message) 143=item on_connect_error => $cb->($handle, $message)
143 144
144This callback is called when the connection could not be 145This callback is called when the connection could not be
145established. C<$!> will contain the relevant error code, and C<$message> a 146established. C<$!> will contain the relevant error code, and C<$message> a
… …
152 153
153=item on_error => $cb->($handle, $fatal, $message) 154=item on_error => $cb->($handle, $fatal, $message)
154 155
155This is the error callback, which is called when, well, some error 156This is the error callback, which is called when, well, some error
156occured, such as not being able to resolve the hostname, failure to 157occured, such as not being able to resolve the hostname, failure to
157connect or a read error. 158connect, or a read error.
158 159
159Some errors are fatal (which is indicated by C<$fatal> being true). On 160Some errors are fatal (which is indicated by C<$fatal> being true). On
160fatal errors the handle object will be destroyed (by a call to C<< -> 161fatal errors the handle object will be destroyed (by a call to C<< ->
161destroy >>) after invoking the error callback (which means you are free to 162destroy >>) after invoking the error callback (which means you are free to
162examine the handle object). Examples of fatal errors are an EOF condition 163examine the handle object). Examples of fatal errors are an EOF condition
163with active (but unsatisifable) read watchers (C<EPIPE>) or I/O errors. In 164with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
164cases where the other side can close the connection at their will it is 165cases where the other side can close the connection at will, it is
165often easiest to not report C<EPIPE> errors in this callback. 166often easiest to not report C<EPIPE> errors in this callback.
166 167
167AnyEvent::Handle tries to find an appropriate error code for you to check 168AnyEvent::Handle tries to find an appropriate error code for you to check
168against, but in some cases (TLS errors), this does not work well. It is 169against, but in some cases (TLS errors), this does not work well. It is
169recommended to always output the C<$message> argument in human-readable 170recommended to always output the C<$message> argument in human-readable
170error messages (it's usually the same as C<"$!">). 171error messages (it's usually the same as C<"$!">).
171 172
172Non-fatal errors can be retried by simply returning, but it is recommended 173Non-fatal errors can be retried by returning, but it is recommended
173to simply ignore this parameter and instead abondon the handle object 174to simply ignore this parameter and instead abondon the handle object
174when this callback is invoked. Examples of non-fatal errors are timeouts 175when this callback is invoked. Examples of non-fatal errors are timeouts
175C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>). 176C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
176 177
177On callback entrance, the value of C<$!> contains the operating system 178On entry to the callback, the value of C<$!> contains the operating
178error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or 179system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
179C<EPROTO>). 180C<EPROTO>).
180 181
181While not mandatory, it is I<highly> recommended to set this callback, as 182While not mandatory, it is I<highly> recommended to set this callback, as
182you will not be notified of errors otherwise. The default simply calls 183you will not be notified of errors otherwise. The default just calls
183C<croak>. 184C<croak>.
184 185
185=item on_read => $cb->($handle) 186=item on_read => $cb->($handle)
186 187
187This sets the default read callback, which is called when data arrives 188This sets the default read callback, which is called when data arrives
… …
192To access (and remove data from) the read buffer, use the C<< ->rbuf >> 193To access (and remove data from) the read buffer, use the C<< ->rbuf >>
193method or access the C<< $handle->{rbuf} >> member directly. Note that you 194method or access the C<< $handle->{rbuf} >> member directly. Note that you
194must not enlarge or modify the read buffer, you can only remove data at 195must not enlarge or modify the read buffer, you can only remove data at
195the beginning from it. 196the beginning from it.
196 197
198You can also call C<< ->push_read (...) >> or any other function that
199modifies the read queue. Or do both. Or ...
200
197When an EOF condition is detected then AnyEvent::Handle will first try to 201When an EOF condition is detected, AnyEvent::Handle will first try to
198feed all the remaining data to the queued callbacks and C<on_read> before 202feed all the remaining data to the queued callbacks and C<on_read> before
199calling the C<on_eof> callback. If no progress can be made, then a fatal 203calling the C<on_eof> callback. If no progress can be made, then a fatal
200error will be raised (with C<$!> set to C<EPIPE>). 204error will be raised (with C<$!> set to C<EPIPE>).
201 205
202Note that, unlike requests in the read queue, an C<on_read> callback 206Note that, unlike requests in the read queue, an C<on_read> callback
… …
221set, then a fatal error will be raised with C<$!> set to <0>. 225set, then a fatal error will be raised with C<$!> set to <0>.
222 226
223=item on_drain => $cb->($handle) 227=item on_drain => $cb->($handle)
224 228
225This sets the callback that is called when the write buffer becomes empty 229This sets the callback that is called when the write buffer becomes empty
226(or when the callback is set and the buffer is empty already). 230(or immediately if the buffer is empty already).
227 231
228To append to the write buffer, use the C<< ->push_write >> method. 232To append to the write buffer, use the C<< ->push_write >> method.
229 233
230This callback is useful when you don't want to put all of your write data 234This callback is useful when you don't want to put all of your write data
231into the queue at once, for example, when you want to write the contents 235into the queue at once, for example, when you want to write the contents
… …
243many seconds pass without a successful read or write on the underlying 247many seconds pass without a successful read or write on the underlying
244file handle (or a call to C<timeout_reset>), the C<on_timeout> callback 248file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
245will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT> 249will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
246error will be raised). 250error will be raised).
247 251
248There are three variants of the timeouts that work fully independent 252There are three variants of the timeouts that work independently
249of each other, for both read and write, just read, and just write: 253of each other, for both read and write, just read, and just write:
250C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks 254C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
251C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions 255C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
252C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>. 256C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
253 257
254Note that timeout processing is also active when you currently do not have 258Note that timeout processing is active even when you do not have
255any outstanding read or write requests: If you plan to keep the connection 259any outstanding read or write requests: If you plan to keep the connection
256idle then you should disable the timout temporarily or ignore the timeout 260idle then you should disable the timeout temporarily or ignore the timeout
257in the C<on_timeout> callback, in which case AnyEvent::Handle will simply 261in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
258restart the timeout. 262restart the timeout.
259 263
260Zero (the default) disables this timeout. 264Zero (the default) disables this timeout.
261 265
… …
275be configured to accept only so-and-so much data that it cannot act on 279be configured to accept only so-and-so much data that it cannot act on
276(for example, when expecting a line, an attacker could send an unlimited 280(for example, when expecting a line, an attacker could send an unlimited
277amount of data without a callback ever being called as long as the line 281amount of data without a callback ever being called as long as the line
278isn't finished). 282isn't finished).
279 283
284=item wbuf_max => <bytes>
285
286If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
287when the write buffer ever (strictly) exceeds this size. This is useful to
288avoid some forms of denial-of-service attacks.
289
290Although the units of this parameter is bytes, this is the I<raw> number
291of bytes not yet accepted by the kernel. This can make a difference when
292you e.g. use TLS, as TLS typically makes your write data larger (but it
293can also make it smaller due to compression).
294
295As an example of when this limit is useful, take a chat server that sends
296chat messages to a client. If the client does not read those in a timely
297manner then the send buffer in the server would grow unbounded.
298
280=item autocork => <boolean> 299=item autocork => <boolean>
281 300
282When disabled (the default), then C<push_write> will try to immediately 301When disabled (the default), C<push_write> will try to immediately
283write the data to the handle, if possible. This avoids having to register 302write the data to the handle if possible. This avoids having to register
284a write watcher and wait for the next event loop iteration, but can 303a write watcher and wait for the next event loop iteration, but can
285be inefficient if you write multiple small chunks (on the wire, this 304be inefficient if you write multiple small chunks (on the wire, this
286disadvantage is usually avoided by your kernel's nagle algorithm, see 305disadvantage is usually avoided by your kernel's nagle algorithm, see
287C<no_delay>, but this option can save costly syscalls). 306C<no_delay>, but this option can save costly syscalls).
288 307
289When enabled, then writes will always be queued till the next event loop 308When enabled, writes will always be queued till the next event loop
290iteration. This is efficient when you do many small writes per iteration, 309iteration. This is efficient when you do many small writes per iteration,
291but less efficient when you do a single write only per iteration (or when 310but less efficient when you do a single write only per iteration (or when
292the write buffer often is full). It also increases write latency. 311the write buffer often is full). It also increases write latency.
293 312
294=item no_delay => <boolean> 313=item no_delay => <boolean>
… …
298the Nagle algorithm, and usually it is beneficial. 317the Nagle algorithm, and usually it is beneficial.
299 318
300In some situations you want as low a delay as possible, which can be 319In some situations you want as low a delay as possible, which can be
301accomplishd by setting this option to a true value. 320accomplishd by setting this option to a true value.
302 321
303The default is your opertaing system's default behaviour (most likely 322The default is your operating system's default behaviour (most likely
304enabled), this option explicitly enables or disables it, if possible. 323enabled). This option explicitly enables or disables it, if possible.
305 324
306=item keepalive => <boolean> 325=item keepalive => <boolean>
307 326
308Enables (default disable) the SO_KEEPALIVE option on the stream socket: 327Enables (default disable) the SO_KEEPALIVE option on the stream socket:
309normally, TCP connections have no time-out once established, so TCP 328normally, TCP connections have no time-out once established, so TCP
310connections, once established, can stay alive forever even when the other 329connections, once established, can stay alive forever even when the other
311side has long gone. TCP keepalives are a cheap way to take down long-lived 330side has long gone. TCP keepalives are a cheap way to take down long-lived
312TCP connections whent he other side becomes unreachable. While the default 331TCP connections when the other side becomes unreachable. While the default
313is OS-dependent, TCP keepalives usually kick in after around two hours, 332is OS-dependent, TCP keepalives usually kick in after around two hours,
314and, if the other side doesn't reply, take down the TCP connection some 10 333and, if the other side doesn't reply, take down the TCP connection some 10
315to 15 minutes later. 334to 15 minutes later.
316 335
317It is harmless to specify this option for file handles that do not support 336It is harmless to specify this option for file handles that do not support
… …
335already have occured on BSD systems), but at least it will protect you 354already have occured on BSD systems), but at least it will protect you
336from most attacks. 355from most attacks.
337 356
338=item read_size => <bytes> 357=item read_size => <bytes>
339 358
340The default read block size (the amount of bytes this module will 359The initial read block size, the number of bytes this module will try to
341try to read during each loop iteration, which affects memory 360read during each loop iteration. Each handle object will consume at least
342requirements). Default: C<8192>. 361this amount of memory for the read buffer as well, so when handling many
362connections requirements). See also C<max_read_size>. Default: C<2048>.
363
364=item max_read_size => <bytes>
365
366The maximum read buffer size used by the dynamic adjustment
367algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
368one go it will double C<read_size> up to the maximum given by this
369option. Default: C<131072> or C<read_size>, whichever is higher.
343 370
344=item low_water_mark => <bytes> 371=item low_water_mark => <bytes>
345 372
346Sets the amount of bytes (default: C<0>) that make up an "empty" write 373Sets the number of bytes (default: C<0>) that make up an "empty" write
347buffer: If the write reaches this size or gets even samller it is 374buffer: If the buffer reaches this size or gets even samller it is
348considered empty. 375considered empty.
349 376
350Sometimes it can be beneficial (for performance reasons) to add data to 377Sometimes it can be beneficial (for performance reasons) to add data to
351the write buffer before it is fully drained, but this is a rare case, as 378the write buffer before it is fully drained, but this is a rare case, as
352the operating system kernel usually buffers data as well, so the default 379the operating system kernel usually buffers data as well, so the default
353is good in almost all cases. 380is good in almost all cases.
354 381
355=item linger => <seconds> 382=item linger => <seconds>
356 383
357If non-zero (default: C<3600>), then the destructor of the 384If this is non-zero (default: C<3600>), the destructor of the
358AnyEvent::Handle object will check whether there is still outstanding 385AnyEvent::Handle object will check whether there is still outstanding
359write data and will install a watcher that will write this data to the 386write data and will install a watcher that will write this data to the
360socket. No errors will be reported (this mostly matches how the operating 387socket. No errors will be reported (this mostly matches how the operating
361system treats outstanding data at socket close time). 388system treats outstanding data at socket close time).
362 389
… …
369A string used to identify the remote site - usually the DNS hostname 396A string used to identify the remote site - usually the DNS hostname
370(I<not> IDN!) used to create the connection, rarely the IP address. 397(I<not> IDN!) used to create the connection, rarely the IP address.
371 398
372Apart from being useful in error messages, this string is also used in TLS 399Apart from being useful in error messages, this string is also used in TLS
373peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This 400peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
374verification will be skipped when C<peername> is not specified or 401verification will be skipped when C<peername> is not specified or is
375C<undef>. 402C<undef>.
376 403
377=item tls => "accept" | "connect" | Net::SSLeay::SSL object 404=item tls => "accept" | "connect" | Net::SSLeay::SSL object
378 405
379When this parameter is given, it enables TLS (SSL) mode, that means 406When this parameter is given, it enables TLS (SSL) mode, that means
… …
405B<IMPORTANT:> since Net::SSLeay "objects" are really only integers, 432B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
406passing in the wrong integer will lead to certain crash. This most often 433passing in the wrong integer will lead to certain crash. This most often
407happens when one uses a stylish C<< tls => 1 >> and is surprised about the 434happens when one uses a stylish C<< tls => 1 >> and is surprised about the
408segmentation fault. 435segmentation fault.
409 436
410See the C<< ->starttls >> method for when need to start TLS negotiation later. 437Use the C<< ->starttls >> method if you need to start TLS negotiation later.
411 438
412=item tls_ctx => $anyevent_tls 439=item tls_ctx => $anyevent_tls
413 440
414Use the given C<AnyEvent::TLS> object to create the new TLS connection 441Use the given C<AnyEvent::TLS> object to create the new TLS connection
415(unless a connection object was specified directly). If this parameter is 442(unless a connection object was specified directly). If this
416missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>. 443parameter is missing (or C<undef>), then AnyEvent::Handle will use
444C<AnyEvent::Handle::TLS_CTX>.
417 445
418Instead of an object, you can also specify a hash reference with C<< key 446Instead of an object, you can also specify a hash reference with C<< key
419=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a 447=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
420new TLS context object. 448new TLS context object.
421 449
… …
430 458
431TLS handshake failures will not cause C<on_error> to be invoked when this 459TLS handshake failures will not cause C<on_error> to be invoked when this
432callback is in effect, instead, the error message will be passed to C<on_starttls>. 460callback is in effect, instead, the error message will be passed to C<on_starttls>.
433 461
434Without this callback, handshake failures lead to C<on_error> being 462Without this callback, handshake failures lead to C<on_error> being
435called, as normal. 463called as usual.
436 464
437Note that you cannot call C<starttls> right again in this callback. If you 465Note that you cannot just call C<starttls> again in this callback. If you
438need to do that, start an zero-second timer instead whose callback can 466need to do that, start an zero-second timer instead whose callback can
439then call C<< ->starttls >> again. 467then call C<< ->starttls >> again.
440 468
441=item on_stoptls => $cb->($handle) 469=item on_stoptls => $cb->($handle)
442 470
… …
489 AnyEvent::Socket::tcp_connect ( 517 AnyEvent::Socket::tcp_connect (
490 $self->{connect}[0], 518 $self->{connect}[0],
491 $self->{connect}[1], 519 $self->{connect}[1],
492 sub { 520 sub {
493 my ($fh, $host, $port, $retry) = @_; 521 my ($fh, $host, $port, $retry) = @_;
522
523 delete $self->{_connect}; # no longer needed
494 524
495 if ($fh) { 525 if ($fh) {
496 $self->{fh} = $fh; 526 $self->{fh} = $fh;
497 527
498 delete $self->{_skip_drain_rbuf}; 528 delete $self->{_skip_drain_rbuf};
… …
516 }, 546 },
517 sub { 547 sub {
518 local $self->{fh} = $_[0]; 548 local $self->{fh} = $_[0];
519 549
520 $self->{on_prepare} 550 $self->{on_prepare}
521 ? $self->{on_prepare}->($self) 551 ? $self->{on_prepare}->($self)
522 : () 552 : ()
523 } 553 }
524 ); 554 );
525 } 555 }
526 556
… …
532} 562}
533 563
534sub _start { 564sub _start {
535 my ($self) = @_; 565 my ($self) = @_;
536 566
567 # too many clueless people try to use udp and similar sockets
568 # with AnyEvent::Handle, do them a favour.
569 my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
570 Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
571 if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
572
537 AnyEvent::Util::fh_nonblocking $self->{fh}, 1; 573 AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
538 574
539 $self->{_activity} = 575 $self->{_activity} =
540 $self->{_ractivity} = 576 $self->{_ractivity} =
541 $self->{_wactivity} = AE::now; 577 $self->{_wactivity} = AE::now;
542 578
579 $self->{read_size} ||= 2048;
580 $self->{max_read_size} = $self->{read_size}
581 if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
582
543 $self->timeout (delete $self->{timeout} ) if $self->{timeout}; 583 $self->timeout (delete $self->{timeout} ) if $self->{timeout};
544 $self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout}; 584 $self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
545 $self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout}; 585 $self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
546 586
547 $self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay}; 587 $self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
… …
550 $self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1); 590 $self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
551 591
552 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx}) 592 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
553 if $self->{tls}; 593 if $self->{tls};
554 594
555 $self->on_drain (delete $self->{on_drain}) if $self->{on_drain}; 595 $self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
556 596
557 $self->start_read 597 $self->start_read
558 if $self->{on_read} || @{ $self->{_queue} }; 598 if $self->{on_read} || @{ $self->{_queue} };
559 599
560 $self->_drain_wbuf; 600 $self->_drain_wbuf;
… …
636=cut 676=cut
637 677
638sub no_delay { 678sub no_delay {
639 $_[0]{no_delay} = $_[1]; 679 $_[0]{no_delay} = $_[1];
640 680
641 eval {
642 local $SIG{__DIE__};
643 setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1] 681 setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
644 if $_[0]{fh}; 682 if $_[0]{fh};
645 };
646} 683}
647 684
648=item $handle->keepalive ($boolean) 685=item $handle->keepalive ($boolean)
649 686
650Enables or disables the C<keepalive> setting (see constructor argument of 687Enables or disables the C<keepalive> setting (see constructor argument of
… …
710 747
711Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument). 748Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
712 749
713=cut 750=cut
714 751
715sub on_starttls { 752sub on_stoptls {
716 $_[0]{on_stoptls} = $_[1]; 753 $_[0]{on_stoptls} = $_[1];
717} 754}
718 755
719=item $handle->rbuf_max ($max_octets) 756=item $handle->rbuf_max ($max_octets)
720 757
721Configures the C<rbuf_max> setting (C<undef> disables it). 758Configures the C<rbuf_max> setting (C<undef> disables it).
759
760=item $handle->wbuf_max ($max_octets)
761
762Configures the C<wbuf_max> setting (C<undef> disables it).
722 763
723=cut 764=cut
724 765
725sub rbuf_max { 766sub rbuf_max {
726 $_[0]{rbuf_max} = $_[1]; 767 $_[0]{rbuf_max} = $_[1];
768}
769
770sub rbuf_max {
771 $_[0]{wbuf_max} = $_[1];
727} 772}
728 773
729############################################################################# 774#############################################################################
730 775
731=item $handle->timeout ($seconds) 776=item $handle->timeout ($seconds)
… …
759 $_[0]{$on_timeout} = $_[1]; 804 $_[0]{$on_timeout} = $_[1];
760 }; 805 };
761 806
762 *$timeout = sub { 807 *$timeout = sub {
763 my ($self, $new_value) = @_; 808 my ($self, $new_value) = @_;
809
810 $new_value >= 0
811 or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
764 812
765 $self->{$timeout} = $new_value; 813 $self->{$timeout} = $new_value;
766 delete $self->{$tw}; &$cb; 814 delete $self->{$tw}; &$cb;
767 }; 815 };
768 816
… …
832=item $handle->on_drain ($cb) 880=item $handle->on_drain ($cb)
833 881
834Sets the C<on_drain> callback or clears it (see the description of 882Sets the C<on_drain> callback or clears it (see the description of
835C<on_drain> in the constructor). 883C<on_drain> in the constructor).
836 884
885This method may invoke callbacks (and therefore the handle might be
886destroyed after it returns).
887
837=cut 888=cut
838 889
839sub on_drain { 890sub on_drain {
840 my ($self, $cb) = @_; 891 my ($self, $cb) = @_;
841 892
… …
845 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf}); 896 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
846} 897}
847 898
848=item $handle->push_write ($data) 899=item $handle->push_write ($data)
849 900
850Queues the given scalar to be written. You can push as much data as you 901Queues the given scalar to be written. You can push as much data as
851want (only limited by the available memory), as C<AnyEvent::Handle> 902you want (only limited by the available memory and C<wbuf_max>), as
852buffers it independently of the kernel. 903C<AnyEvent::Handle> buffers it independently of the kernel.
904
905This method may invoke callbacks (and therefore the handle might be
906destroyed after it returns).
853 907
854=cut 908=cut
855 909
856sub _drain_wbuf { 910sub _drain_wbuf {
857 my ($self) = @_; 911 my ($self) = @_;
… …
882 $cb->() unless $self->{autocork}; 936 $cb->() unless $self->{autocork};
883 937
884 # if still data left in wbuf, we need to poll 938 # if still data left in wbuf, we need to poll
885 $self->{_ww} = AE::io $self->{fh}, 1, $cb 939 $self->{_ww} = AE::io $self->{fh}, 1, $cb
886 if length $self->{wbuf}; 940 if length $self->{wbuf};
941
942 if (
943 defined $self->{wbuf_max}
944 && $self->{wbuf_max} < length $self->{wbuf}
945 ) {
946 $self->_error (Errno::ENOSPC, 1), return;
947 }
887 }; 948 };
888} 949}
889 950
890our %WH; 951our %WH;
891 952
… …
903 @_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type" 964 @_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
904 or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write") 965 or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
905 ->($self, @_); 966 ->($self, @_);
906 } 967 }
907 968
969 # we downgrade here to avoid hard-to-track-down bugs,
970 # and diagnose the problem earlier and better.
971
908 if ($self->{tls}) { 972 if ($self->{tls}) {
909 $self->{_tls_wbuf} .= $_[0]; 973 utf8::downgrade $self->{_tls_wbuf} .= $_[0];
910 &_dotls ($self) if $self->{fh}; 974 &_dotls ($self) if $self->{fh};
911 } else { 975 } else {
912 $self->{wbuf} .= $_[0]; 976 utf8::downgrade $self->{wbuf} .= $_[0];
913 $self->_drain_wbuf if $self->{fh}; 977 $self->_drain_wbuf if $self->{fh};
914 } 978 }
915} 979}
916 980
917=item $handle->push_write (type => @args) 981=item $handle->push_write (type => @args)
918 982
919Instead of formatting your data yourself, you can also let this module 983Instead of formatting your data yourself, you can also let this module
920do the job by specifying a type and type-specific arguments. You 984do the job by specifying a type and type-specific arguments. You
921can also specify the (fully qualified) name of a package, in which 985can also specify the (fully qualified) name of a package, in which
922case AnyEvent tries to load the package and then expects to find the 986case AnyEvent tries to load the package and then expects to find the
923C<anyevent_read_type> function inside (see "custom write types", below). 987C<anyevent_write_type> function inside (see "custom write types", below).
924 988
925Predefined types are (if you have ideas for additional types, feel free to 989Predefined types are (if you have ideas for additional types, feel free to
926drop by and tell us): 990drop by and tell us):
927 991
928=over 4 992=over 4
… …
1031the peer. 1095the peer.
1032 1096
1033You can rely on the normal read queue and C<on_eof> handling 1097You can rely on the normal read queue and C<on_eof> handling
1034afterwards. This is the cleanest way to close a connection. 1098afterwards. This is the cleanest way to close a connection.
1035 1099
1100This method may invoke callbacks (and therefore the handle might be
1101destroyed after it returns).
1102
1036=cut 1103=cut
1037 1104
1038sub push_shutdown { 1105sub push_shutdown {
1039 my ($self) = @_; 1106 my ($self) = @_;
1040 1107
… …
1089ways, the "simple" way, using only C<on_read> and the "complex" way, using 1156ways, the "simple" way, using only C<on_read> and the "complex" way, using
1090a queue. 1157a queue.
1091 1158
1092In the simple case, you just install an C<on_read> callback and whenever 1159In the simple case, you just install an C<on_read> callback and whenever
1093new data arrives, it will be called. You can then remove some data (if 1160new data arrives, it will be called. You can then remove some data (if
1094enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna 1161enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
1095leave the data there if you want to accumulate more (e.g. when only a 1162leave the data there if you want to accumulate more (e.g. when only a
1096partial message has been received so far). 1163partial message has been received so far), or change the read queue with
1164e.g. C<push_read>.
1097 1165
1098In the more complex case, you want to queue multiple callbacks. In this 1166In the more complex case, you want to queue multiple callbacks. In this
1099case, AnyEvent::Handle will call the first queued callback each time new 1167case, AnyEvent::Handle will call the first queued callback each time new
1100data arrives (also the first time it is queued) and removes it when it has 1168data arrives (also the first time it is queued) and remove it when it has
1101done its job (see C<push_read>, below). 1169done its job (see C<push_read>, below).
1102 1170
1103This way you can, for example, push three line-reads, followed by reading 1171This way you can, for example, push three line-reads, followed by reading
1104a chunk of data, and AnyEvent::Handle will execute them in order. 1172a chunk of data, and AnyEvent::Handle will execute them in order.
1105 1173
… …
1236 1304
1237This replaces the currently set C<on_read> callback, or clears it (when 1305This replaces the currently set C<on_read> callback, or clears it (when
1238the new callback is C<undef>). See the description of C<on_read> in the 1306the new callback is C<undef>). See the description of C<on_read> in the
1239constructor. 1307constructor.
1240 1308
1309This method may invoke callbacks (and therefore the handle might be
1310destroyed after it returns).
1311
1241=cut 1312=cut
1242 1313
1243sub on_read { 1314sub on_read {
1244 my ($self, $cb) = @_; 1315 my ($self, $cb) = @_;
1245 1316
… …
1247 $self->_drain_rbuf if $cb; 1318 $self->_drain_rbuf if $cb;
1248} 1319}
1249 1320
1250=item $handle->rbuf 1321=item $handle->rbuf
1251 1322
1252Returns the read buffer (as a modifiable lvalue). 1323Returns the read buffer (as a modifiable lvalue). You can also access the
1324read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
1325much faster, and no less clean).
1253 1326
1254You can access the read buffer directly as the C<< ->{rbuf} >> 1327The only operation allowed on the read buffer (apart from looking at it)
1255member, if you want. However, the only operation allowed on the 1328is removing data from its beginning. Otherwise modifying or appending to
1256read buffer (apart from looking at it) is removing data from its 1329it is not allowed and will lead to hard-to-track-down bugs.
1257beginning. Otherwise modifying or appending to it is not allowed and will
1258lead to hard-to-track-down bugs.
1259 1330
1260NOTE: The read buffer should only be used or modified if the C<on_read>, 1331NOTE: The read buffer should only be used or modified in the C<on_read>
1261C<push_read> or C<unshift_read> methods are used. The other read methods 1332callback or when C<push_read> or C<unshift_read> are used with a single
1262automatically manage the read buffer. 1333callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
1334will manage the read buffer on their own.
1263 1335
1264=cut 1336=cut
1265 1337
1266sub rbuf : lvalue { 1338sub rbuf : lvalue {
1267 $_[0]{rbuf} 1339 $_[0]{rbuf}
… …
1284 1356
1285If enough data was available, then the callback must remove all data it is 1357If enough data was available, then the callback must remove all data it is
1286interested in (which can be none at all) and return a true value. After returning 1358interested in (which can be none at all) and return a true value. After returning
1287true, it will be removed from the queue. 1359true, it will be removed from the queue.
1288 1360
1361These methods may invoke callbacks (and therefore the handle might be
1362destroyed after it returns).
1363
1289=cut 1364=cut
1290 1365
1291our %RH; 1366our %RH;
1292 1367
1293sub register_read_type($$) { 1368sub register_read_type($$) {
… …
1315 my $cb = pop; 1390 my $cb = pop;
1316 1391
1317 if (@_) { 1392 if (@_) {
1318 my $type = shift; 1393 my $type = shift;
1319 1394
1395 $cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
1320 $cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read") 1396 or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
1321 ->($self, $cb, @_); 1397 ->($self, $cb, @_);
1322 } 1398 }
1323 1399
1324 unshift @{ $self->{_queue} }, $cb; 1400 unshift @{ $self->{_queue} }, $cb;
1325 $self->_drain_rbuf; 1401 $self->_drain_rbuf;
… …
1433the receive buffer when neither C<$accept> nor C<$reject> match, 1509the receive buffer when neither C<$accept> nor C<$reject> match,
1434and everything preceding and including the match will be accepted 1510and everything preceding and including the match will be accepted
1435unconditionally. This is useful to skip large amounts of data that you 1511unconditionally. This is useful to skip large amounts of data that you
1436know cannot be matched, so that the C<$accept> or C<$reject> regex do not 1512know cannot be matched, so that the C<$accept> or C<$reject> regex do not
1437have to start matching from the beginning. This is purely an optimisation 1513have to start matching from the beginning. This is purely an optimisation
1438and is usually worth only when you expect more than a few kilobytes. 1514and is usually worth it only when you expect more than a few kilobytes.
1439 1515
1440Example: expect a http header, which ends at C<\015\012\015\012>. Since we 1516Example: expect a http header, which ends at C<\015\012\015\012>. Since we
1441expect the header to be very large (it isn't in practise, but...), we use 1517expect the header to be very large (it isn't in practice, but...), we use
1442a skip regex to skip initial portions. The skip regex is tricky in that 1518a skip regex to skip initial portions. The skip regex is tricky in that
1443it only accepts something not ending in either \015 or \012, as these are 1519it only accepts something not ending in either \015 or \012, as these are
1444required for the accept regex. 1520required for the accept regex.
1445 1521
1446 $handle->push_read (regex => 1522 $handle->push_read (regex =>
… …
1711} 1787}
1712 1788
1713sub start_read { 1789sub start_read {
1714 my ($self) = @_; 1790 my ($self) = @_;
1715 1791
1716 unless ($self->{_rw} || $self->{_eof}) { 1792 unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
1717 Scalar::Util::weaken $self; 1793 Scalar::Util::weaken $self;
1718 1794
1719 $self->{_rw} = AE::io $self->{fh}, 0, sub { 1795 $self->{_rw} = AE::io $self->{fh}, 0, sub {
1720 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf}); 1796 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1721 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf; 1797 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
1722 1798
1723 if ($len > 0) { 1799 if ($len > 0) {
1724 $self->{_activity} = $self->{_ractivity} = AE::now; 1800 $self->{_activity} = $self->{_ractivity} = AE::now;
1725 1801
1726 if ($self->{tls}) { 1802 if ($self->{tls}) {
1727 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf); 1803 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1728 1804
1729 &_dotls ($self); 1805 &_dotls ($self);
1730 } else { 1806 } else {
1731 $self->_drain_rbuf; 1807 $self->_drain_rbuf;
1808 }
1809
1810 if ($len == $self->{read_size}) {
1811 $self->{read_size} *= 2;
1812 $self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
1813 if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
1732 } 1814 }
1733 1815
1734 } elsif (defined $len) { 1816 } elsif (defined $len) {
1735 delete $self->{_rw}; 1817 delete $self->{_rw};
1736 $self->{_eof} = 1; 1818 $self->{_eof} = 1;
… …
1814 && ($tmp != $ERROR_SYSCALL || $!); 1896 && ($tmp != $ERROR_SYSCALL || $!);
1815 1897
1816 while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) { 1898 while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1817 $self->{wbuf} .= $tmp; 1899 $self->{wbuf} .= $tmp;
1818 $self->_drain_wbuf; 1900 $self->_drain_wbuf;
1901 $self->{tls} or return; # tls session might have gone away in callback
1819 } 1902 }
1820 1903
1821 $self->{_on_starttls} 1904 $self->{_on_starttls}
1822 and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK () 1905 and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
1823 and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established"); 1906 and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
… …
1845context in C<< $handle->{tls_ctx} >> after this call and can be used or 1928context in C<< $handle->{tls_ctx} >> after this call and can be used or
1846changed to your liking. Note that the handshake might have already started 1929changed to your liking. Note that the handshake might have already started
1847when this function returns. 1930when this function returns.
1848 1931
1849Due to bugs in OpenSSL, it might or might not be possible to do multiple 1932Due to bugs in OpenSSL, it might or might not be possible to do multiple
1850handshakes on the same stream. Best do not attempt to use the stream after 1933handshakes on the same stream. It is best to not attempt to use the
1851stopping TLS. 1934stream after stopping TLS.
1935
1936This method may invoke callbacks (and therefore the handle might be
1937destroyed after it returns).
1852 1938
1853=cut 1939=cut
1854 1940
1855our %TLS_CACHE; #TODO not yet documented, should we? 1941our %TLS_CACHE; #TODO not yet documented, should we?
1856 1942
… …
1922 2008
1923=item $handle->stoptls 2009=item $handle->stoptls
1924 2010
1925Shuts down the SSL connection - this makes a proper EOF handshake by 2011Shuts down the SSL connection - this makes a proper EOF handshake by
1926sending a close notify to the other side, but since OpenSSL doesn't 2012sending a close notify to the other side, but since OpenSSL doesn't
1927support non-blocking shut downs, it is not guarenteed that you can re-use 2013support non-blocking shut downs, it is not guaranteed that you can re-use
1928the stream afterwards. 2014the stream afterwards.
2015
2016This method may invoke callbacks (and therefore the handle might be
2017destroyed after it returns).
1929 2018
1930=cut 2019=cut
1931 2020
1932sub stoptls { 2021sub stoptls {
1933 my ($self) = @_; 2022 my ($self) = @_;
1934 2023
1935 if ($self->{tls}) { 2024 if ($self->{tls} && $self->{fh}) {
1936 Net::SSLeay::shutdown ($self->{tls}); 2025 Net::SSLeay::shutdown ($self->{tls});
1937 2026
1938 &_dotls; 2027 &_dotls;
1939 2028
1940# # we don't give a shit. no, we do, but we can't. no...#d# 2029# # we don't give a shit. no, we do, but we can't. no...#d#
… …
1970 push @linger, AE::io $fh, 1, sub { 2059 push @linger, AE::io $fh, 1, sub {
1971 my $len = syswrite $fh, $wbuf, length $wbuf; 2060 my $len = syswrite $fh, $wbuf, length $wbuf;
1972 2061
1973 if ($len > 0) { 2062 if ($len > 0) {
1974 substr $wbuf, 0, $len, ""; 2063 substr $wbuf, 0, $len, "";
1975 } else { 2064 } elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
1976 @linger = (); # end 2065 @linger = (); # end
1977 } 2066 }
1978 }; 2067 };
1979 push @linger, AE::timer $linger, 0, sub { 2068 push @linger, AE::timer $linger, 0, sub {
1980 @linger = (); 2069 @linger = ();
… …
2017 2106
2018sub AnyEvent::Handle::destroyed::AUTOLOAD { 2107sub AnyEvent::Handle::destroyed::AUTOLOAD {
2019 #nop 2108 #nop
2020} 2109}
2021 2110
2111=item $handle->destroyed
2112
2113Returns false as long as the handle hasn't been destroyed by a call to C<<
2114->destroy >>, true otherwise.
2115
2116Can be useful to decide whether the handle is still valid after some
2117callback possibly destroyed the handle. For example, C<< ->push_write >>,
2118C<< ->starttls >> and other methods can call user callbacks, which in turn
2119can destroy the handle, so work can be avoided by checking sometimes:
2120
2121 $hdl->starttls ("accept");
2122 return if $hdl->destroyed;
2123 $hdl->push_write (...
2124
2125Note that the call to C<push_write> will silently be ignored if the handle
2126has been destroyed, so often you can just ignore the possibility of the
2127handle being destroyed.
2128
2129=cut
2130
2131sub destroyed { 0 }
2132sub AnyEvent::Handle::destroyed::destroyed { 1 }
2133
2022=item AnyEvent::Handle::TLS_CTX 2134=item AnyEvent::Handle::TLS_CTX
2023 2135
2024This function creates and returns the AnyEvent::TLS object used by default 2136This function creates and returns the AnyEvent::TLS object used by default
2025for TLS mode. 2137for TLS mode.
2026 2138
… …
2053 2165
2054It is only safe to "forget" the reference inside EOF or error callbacks, 2166It is only safe to "forget" the reference inside EOF or error callbacks,
2055from within all other callbacks, you need to explicitly call the C<< 2167from within all other callbacks, you need to explicitly call the C<<
2056->destroy >> method. 2168->destroy >> method.
2057 2169
2170=item Why is my C<on_eof> callback never called?
2171
2172Probably because your C<on_error> callback is being called instead: When
2173you have outstanding requests in your read queue, then an EOF is
2174considered an error as you clearly expected some data.
2175
2176To avoid this, make sure you have an empty read queue whenever your handle
2177is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
2178an C<on_read> handler that simply pushes the first read requests in the
2179queue.
2180
2181See also the next question, which explains this in a bit more detail.
2182
2183=item How can I serve requests in a loop?
2184
2185Most protocols consist of some setup phase (authentication for example)
2186followed by a request handling phase, where the server waits for requests
2187and handles them, in a loop.
2188
2189There are two important variants: The first (traditional, better) variant
2190handles requests until the server gets some QUIT command, causing it to
2191close the connection first (highly desirable for a busy TCP server). A
2192client dropping the connection is an error, which means this variant can
2193detect an unexpected detection close.
2194
2195To handle this case, always make sure you have a on-empty read queue, by
2196pushing the "read request start" handler on it:
2197
2198 # we assume a request starts with a single line
2199 my @start_request; @start_request = (line => sub {
2200 my ($hdl, $line) = @_;
2201
2202 ... handle request
2203
2204 # push next request read, possibly from a nested callback
2205 $hdl->push_read (@start_request);
2206 });
2207
2208 # auth done, now go into request handling loop
2209 # now push the first @start_request
2210 $hdl->push_read (@start_request);
2211
2212By always having an outstanding C<push_read>, the handle always expects
2213some data and raises the C<EPIPE> error when the connction is dropped
2214unexpectedly.
2215
2216The second variant is a protocol where the client can drop the connection
2217at any time. For TCP, this means that the server machine may run out of
2218sockets easier, and in general, it means you cnanot distinguish a protocl
2219failure/client crash from a normal connection close. Nevertheless, these
2220kinds of protocols are common (and sometimes even the best solution to the
2221problem).
2222
2223Having an outstanding read request at all times is possible if you ignore
2224C<EPIPE> errors, but this doesn't help with when the client drops the
2225connection during a request, which would still be an error.
2226
2227A better solution is to push the initial request read in an C<on_read>
2228callback. This avoids an error, as when the server doesn't expect data
2229(i.e. is idly waiting for the next request, an EOF will not raise an
2230error, but simply result in an C<on_eof> callback. It is also a bit slower
2231and simpler:
2232
2233 # auth done, now go into request handling loop
2234 $hdl->on_read (sub {
2235 my ($hdl) = @_;
2236
2237 # called each time we receive data but the read queue is empty
2238 # simply start read the request
2239
2240 $hdl->push_read (line => sub {
2241 my ($hdl, $line) = @_;
2242
2243 ... handle request
2244
2245 # do nothing special when the request has been handled, just
2246 # let the request queue go empty.
2247 });
2248 });
2249
2058=item I get different callback invocations in TLS mode/Why can't I pause 2250=item I get different callback invocations in TLS mode/Why can't I pause
2059reading? 2251reading?
2060 2252
2061Unlike, say, TCP, TLS connections do not consist of two independent 2253Unlike, say, TCP, TLS connections do not consist of two independent
2062communication channels, one for each direction. Or put differently. The 2254communication channels, one for each direction. Or put differently, the
2063read and write directions are not independent of each other: you cannot 2255read and write directions are not independent of each other: you cannot
2064write data unless you are also prepared to read, and vice versa. 2256write data unless you are also prepared to read, and vice versa.
2065 2257
2066This can mean than, in TLS mode, you might get C<on_error> or C<on_eof> 2258This means that, in TLS mode, you might get C<on_error> or C<on_eof>
2067callback invocations when you are not expecting any read data - the reason 2259callback invocations when you are not expecting any read data - the reason
2068is that AnyEvent::Handle always reads in TLS mode. 2260is that AnyEvent::Handle always reads in TLS mode.
2069 2261
2070During the connection, you have to make sure that you always have a 2262During the connection, you have to make sure that you always have a
2071non-empty read-queue, or an C<on_read> watcher. At the end of the 2263non-empty read-queue, or an C<on_read> watcher. At the end of the
… …
2085 my $data = delete $_[0]{rbuf}; 2277 my $data = delete $_[0]{rbuf};
2086 }); 2278 });
2087 2279
2088The reason to use C<on_error> is that TCP connections, due to latencies 2280The reason to use C<on_error> is that TCP connections, due to latencies
2089and packets loss, might get closed quite violently with an error, when in 2281and packets loss, might get closed quite violently with an error, when in
2090fact, all data has been received. 2282fact all data has been received.
2091 2283
2092It is usually better to use acknowledgements when transferring data, 2284It is usually better to use acknowledgements when transferring data,
2093to make sure the other side hasn't just died and you got the data 2285to make sure the other side hasn't just died and you got the data
2094intact. This is also one reason why so many internet protocols have an 2286intact. This is also one reason why so many internet protocols have an
2095explicit QUIT command. 2287explicit QUIT command.
… …
2112consider using C<< ->push_shutdown >> instead. 2304consider using C<< ->push_shutdown >> instead.
2113 2305
2114=item I want to contact a TLS/SSL server, I don't care about security. 2306=item I want to contact a TLS/SSL server, I don't care about security.
2115 2307
2116If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS, 2308If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
2117simply connect to it and then create the AnyEvent::Handle with the C<tls> 2309connect to it and then create the AnyEvent::Handle with the C<tls>
2118parameter: 2310parameter:
2119 2311
2120 tcp_connect $host, $port, sub { 2312 tcp_connect $host, $port, sub {
2121 my ($fh) = @_; 2313 my ($fh) = @_;
2122 2314
… …
2222 2414
2223=item * all members not documented here and not prefixed with an underscore 2415=item * all members not documented here and not prefixed with an underscore
2224are free to use in subclasses. 2416are free to use in subclasses.
2225 2417
2226Of course, new versions of AnyEvent::Handle may introduce more "public" 2418Of course, new versions of AnyEvent::Handle may introduce more "public"
2227member variables, but thats just life, at least it is documented. 2419member variables, but that's just life. At least it is documented.
2228 2420
2229=back 2421=back
2230 2422
2231=head1 AUTHOR 2423=head1 AUTHOR
2232 2424

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