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Revision 1.197 by root, Tue Aug 31 00:59:55 2010 UTC vs.
Revision 1.218 by root, Thu Feb 24 12:04:20 2011 UTC

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30 30
31 $cv->recv; 31 $cv->recv;
32 32
33=head1 DESCRIPTION 33=head1 DESCRIPTION
34 34
35This module is a helper module to make it easier to do event-based I/O on 35This is a helper module to make it easier to do event-based I/O on
36stream-based filehandles (sockets, pipes or other stream things). 36stream-based filehandles (sockets, pipes, and other stream things).
37 37
38The L<AnyEvent::Intro> tutorial contains some well-documented 38The L<AnyEvent::Intro> tutorial contains some well-documented
39AnyEvent::Handle examples. 39AnyEvent::Handle examples.
40 40
41In the following, when the documentation refers to of "bytes" then this 41In the following, where the documentation refers to "bytes", it means
42means characters. As sysread and syswrite are used for all I/O, their 42characters. As sysread and syswrite are used for all I/O, their
43treatment of characters applies to this module as well. 43treatment of characters applies to this module as well.
44 44
45At the very minimum, you should specify C<fh> or C<connect>, and the 45At the very minimum, you should specify C<fh> or C<connect>, and the
46C<on_error> callback. 46C<on_error> callback.
47 47
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75 } 75 }
76 76
77 \&$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::Handle fh => $filehandle, key => value... 86=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
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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
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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
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195the beginning from it. 196the beginning from it.
196 197
197You can also call C<< ->push_read (...) >> or any other function that 198You can also call C<< ->push_read (...) >> or any other function that
198modifies the read queue. Or do both. Or ... 199modifies the read queue. Or do both. Or ...
199 200
200When an EOF condition is detected then AnyEvent::Handle will first try to 201When an EOF condition is detected, AnyEvent::Handle will first try to
201feed 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
202calling 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
203error will be raised (with C<$!> set to C<EPIPE>). 204error will be raised (with C<$!> set to C<EPIPE>).
204 205
205Note 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
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224set, 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>.
225 226
226=item on_drain => $cb->($handle) 227=item on_drain => $cb->($handle)
227 228
228This 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
229(or when the callback is set and the buffer is empty already). 230(or immediately if the buffer is empty already).
230 231
231To append to the write buffer, use the C<< ->push_write >> method. 232To append to the write buffer, use the C<< ->push_write >> method.
232 233
233This 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
234into 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
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246many seconds pass without a successful read or write on the underlying 247many seconds pass without a successful read or write on the underlying
247file 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
248will 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>
249error will be raised). 250error will be raised).
250 251
251There are three variants of the timeouts that work fully independent 252There are three variants of the timeouts that work independently of each
252of each other, for both read and write, just read, and just write: 253other, for both read and write (triggered when nothing was read I<OR>
254written), just read (triggered when nothing was read), and just write:
253C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks 255C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
254C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions 256C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
255C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>. 257C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
256 258
257Note that timeout processing is also active when you currently do not have 259Note that timeout processing is active even when you do not have any
258any outstanding read or write requests: If you plan to keep the connection 260outstanding read or write requests: If you plan to keep the connection
259idle then you should disable the timout temporarily or ignore the timeout 261idle then you should disable the timeout temporarily or ignore the
260in the C<on_timeout> callback, in which case AnyEvent::Handle will simply 262timeout in the corresponding C<on_timeout> callback, in which case
261restart the timeout. 263AnyEvent::Handle will simply restart the timeout.
262 264
263Zero (the default) disables this timeout. 265Zero (the default) disables the corresponding timeout.
264 266
265=item on_timeout => $cb->($handle) 267=item on_timeout => $cb->($handle)
268
269=item on_rtimeout => $cb->($handle)
270
271=item on_wtimeout => $cb->($handle)
266 272
267Called whenever the inactivity timeout passes. If you return from this 273Called whenever the inactivity timeout passes. If you return from this
268callback, then the timeout will be reset as if some activity had happened, 274callback, then the timeout will be reset as if some activity had happened,
269so this condition is not fatal in any way. 275so this condition is not fatal in any way.
270 276
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278be configured to accept only so-and-so much data that it cannot act on 284be configured to accept only so-and-so much data that it cannot act on
279(for example, when expecting a line, an attacker could send an unlimited 285(for example, when expecting a line, an attacker could send an unlimited
280amount of data without a callback ever being called as long as the line 286amount of data without a callback ever being called as long as the line
281isn't finished). 287isn't finished).
282 288
289=item wbuf_max => <bytes>
290
291If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
292when the write buffer ever (strictly) exceeds this size. This is useful to
293avoid some forms of denial-of-service attacks.
294
295Although the units of this parameter is bytes, this is the I<raw> number
296of bytes not yet accepted by the kernel. This can make a difference when
297you e.g. use TLS, as TLS typically makes your write data larger (but it
298can also make it smaller due to compression).
299
300As an example of when this limit is useful, take a chat server that sends
301chat messages to a client. If the client does not read those in a timely
302manner then the send buffer in the server would grow unbounded.
303
283=item autocork => <boolean> 304=item autocork => <boolean>
284 305
285When disabled (the default), then C<push_write> will try to immediately 306When disabled (the default), C<push_write> will try to immediately
286write the data to the handle, if possible. This avoids having to register 307write the data to the handle if possible. This avoids having to register
287a write watcher and wait for the next event loop iteration, but can 308a write watcher and wait for the next event loop iteration, but can
288be inefficient if you write multiple small chunks (on the wire, this 309be inefficient if you write multiple small chunks (on the wire, this
289disadvantage is usually avoided by your kernel's nagle algorithm, see 310disadvantage is usually avoided by your kernel's nagle algorithm, see
290C<no_delay>, but this option can save costly syscalls). 311C<no_delay>, but this option can save costly syscalls).
291 312
292When enabled, then writes will always be queued till the next event loop 313When enabled, writes will always be queued till the next event loop
293iteration. This is efficient when you do many small writes per iteration, 314iteration. This is efficient when you do many small writes per iteration,
294but less efficient when you do a single write only per iteration (or when 315but less efficient when you do a single write only per iteration (or when
295the write buffer often is full). It also increases write latency. 316the write buffer often is full). It also increases write latency.
296 317
297=item no_delay => <boolean> 318=item no_delay => <boolean>
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301the Nagle algorithm, and usually it is beneficial. 322the Nagle algorithm, and usually it is beneficial.
302 323
303In some situations you want as low a delay as possible, which can be 324In some situations you want as low a delay as possible, which can be
304accomplishd by setting this option to a true value. 325accomplishd by setting this option to a true value.
305 326
306The default is your opertaing system's default behaviour (most likely 327The default is your operating system's default behaviour (most likely
307enabled), this option explicitly enables or disables it, if possible. 328enabled). This option explicitly enables or disables it, if possible.
308 329
309=item keepalive => <boolean> 330=item keepalive => <boolean>
310 331
311Enables (default disable) the SO_KEEPALIVE option on the stream socket: 332Enables (default disable) the SO_KEEPALIVE option on the stream socket:
312normally, TCP connections have no time-out once established, so TCP 333normally, TCP connections have no time-out once established, so TCP
313connections, once established, can stay alive forever even when the other 334connections, once established, can stay alive forever even when the other
314side has long gone. TCP keepalives are a cheap way to take down long-lived 335side has long gone. TCP keepalives are a cheap way to take down long-lived
315TCP connections whent he other side becomes unreachable. While the default 336TCP connections when the other side becomes unreachable. While the default
316is OS-dependent, TCP keepalives usually kick in after around two hours, 337is OS-dependent, TCP keepalives usually kick in after around two hours,
317and, if the other side doesn't reply, take down the TCP connection some 10 338and, if the other side doesn't reply, take down the TCP connection some 10
318to 15 minutes later. 339to 15 minutes later.
319 340
320It is harmless to specify this option for file handles that do not support 341It is harmless to specify this option for file handles that do not support
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338already have occured on BSD systems), but at least it will protect you 359already have occured on BSD systems), but at least it will protect you
339from most attacks. 360from most attacks.
340 361
341=item read_size => <bytes> 362=item read_size => <bytes>
342 363
343The default read block size (the amount of bytes this module will 364The initial read block size, the number of bytes this module will try to
344try to read during each loop iteration, which affects memory 365read during each loop iteration. Each handle object will consume at least
345requirements). Default: C<8192>. 366this amount of memory for the read buffer as well, so when handling many
367connections requirements). See also C<max_read_size>. Default: C<2048>.
368
369=item max_read_size => <bytes>
370
371The maximum read buffer size used by the dynamic adjustment
372algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
373one go it will double C<read_size> up to the maximum given by this
374option. Default: C<131072> or C<read_size>, whichever is higher.
346 375
347=item low_water_mark => <bytes> 376=item low_water_mark => <bytes>
348 377
349Sets the amount of bytes (default: C<0>) that make up an "empty" write 378Sets the number of bytes (default: C<0>) that make up an "empty" write
350buffer: If the write reaches this size or gets even samller it is 379buffer: If the buffer reaches this size or gets even samller it is
351considered empty. 380considered empty.
352 381
353Sometimes it can be beneficial (for performance reasons) to add data to 382Sometimes it can be beneficial (for performance reasons) to add data to
354the write buffer before it is fully drained, but this is a rare case, as 383the write buffer before it is fully drained, but this is a rare case, as
355the operating system kernel usually buffers data as well, so the default 384the operating system kernel usually buffers data as well, so the default
356is good in almost all cases. 385is good in almost all cases.
357 386
358=item linger => <seconds> 387=item linger => <seconds>
359 388
360If non-zero (default: C<3600>), then the destructor of the 389If this is non-zero (default: C<3600>), the destructor of the
361AnyEvent::Handle object will check whether there is still outstanding 390AnyEvent::Handle object will check whether there is still outstanding
362write data and will install a watcher that will write this data to the 391write data and will install a watcher that will write this data to the
363socket. No errors will be reported (this mostly matches how the operating 392socket. No errors will be reported (this mostly matches how the operating
364system treats outstanding data at socket close time). 393system treats outstanding data at socket close time).
365 394
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372A string used to identify the remote site - usually the DNS hostname 401A string used to identify the remote site - usually the DNS hostname
373(I<not> IDN!) used to create the connection, rarely the IP address. 402(I<not> IDN!) used to create the connection, rarely the IP address.
374 403
375Apart from being useful in error messages, this string is also used in TLS 404Apart from being useful in error messages, this string is also used in TLS
376peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This 405peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
377verification will be skipped when C<peername> is not specified or 406verification will be skipped when C<peername> is not specified or is
378C<undef>. 407C<undef>.
379 408
380=item tls => "accept" | "connect" | Net::SSLeay::SSL object 409=item tls => "accept" | "connect" | Net::SSLeay::SSL object
381 410
382When this parameter is given, it enables TLS (SSL) mode, that means 411When this parameter is given, it enables TLS (SSL) mode, that means
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408B<IMPORTANT:> since Net::SSLeay "objects" are really only integers, 437B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
409passing in the wrong integer will lead to certain crash. This most often 438passing in the wrong integer will lead to certain crash. This most often
410happens when one uses a stylish C<< tls => 1 >> and is surprised about the 439happens when one uses a stylish C<< tls => 1 >> and is surprised about the
411segmentation fault. 440segmentation fault.
412 441
413See the C<< ->starttls >> method for when need to start TLS negotiation later. 442Use the C<< ->starttls >> method if you need to start TLS negotiation later.
414 443
415=item tls_ctx => $anyevent_tls 444=item tls_ctx => $anyevent_tls
416 445
417Use the given C<AnyEvent::TLS> object to create the new TLS connection 446Use the given C<AnyEvent::TLS> object to create the new TLS connection
418(unless a connection object was specified directly). If this parameter is 447(unless a connection object was specified directly). If this
419missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>. 448parameter is missing (or C<undef>), then AnyEvent::Handle will use
449C<AnyEvent::Handle::TLS_CTX>.
420 450
421Instead of an object, you can also specify a hash reference with C<< key 451Instead of an object, you can also specify a hash reference with C<< key
422=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a 452=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
423new TLS context object. 453new TLS context object.
424 454
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433 463
434TLS handshake failures will not cause C<on_error> to be invoked when this 464TLS handshake failures will not cause C<on_error> to be invoked when this
435callback is in effect, instead, the error message will be passed to C<on_starttls>. 465callback is in effect, instead, the error message will be passed to C<on_starttls>.
436 466
437Without this callback, handshake failures lead to C<on_error> being 467Without this callback, handshake failures lead to C<on_error> being
438called, as normal. 468called as usual.
439 469
440Note that you cannot call C<starttls> right again in this callback. If you 470Note that you cannot just call C<starttls> again in this callback. If you
441need to do that, start an zero-second timer instead whose callback can 471need to do that, start an zero-second timer instead whose callback can
442then call C<< ->starttls >> again. 472then call C<< ->starttls >> again.
443 473
444=item on_stoptls => $cb->($handle) 474=item on_stoptls => $cb->($handle)
445 475
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493 $self->{connect}[0], 523 $self->{connect}[0],
494 $self->{connect}[1], 524 $self->{connect}[1],
495 sub { 525 sub {
496 my ($fh, $host, $port, $retry) = @_; 526 my ($fh, $host, $port, $retry) = @_;
497 527
528 delete $self->{_connect}; # no longer needed
529
498 if ($fh) { 530 if ($fh) {
499 $self->{fh} = $fh; 531 $self->{fh} = $fh;
500 532
501 delete $self->{_skip_drain_rbuf}; 533 delete $self->{_skip_drain_rbuf};
502 $self->_start; 534 $self->_start;
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509 }); 541 });
510 542
511 } else { 543 } else {
512 if ($self->{on_connect_error}) { 544 if ($self->{on_connect_error}) {
513 $self->{on_connect_error}($self, "$!"); 545 $self->{on_connect_error}($self, "$!");
514 $self->destroy; 546 $self->destroy if $self;
515 } else { 547 } else {
516 $self->_error ($!, 1); 548 $self->_error ($!, 1);
517 } 549 }
518 } 550 }
519 }, 551 },
520 sub { 552 sub {
521 local $self->{fh} = $_[0]; 553 local $self->{fh} = $_[0];
522 554
523 $self->{on_prepare} 555 $self->{on_prepare}
524 ? $self->{on_prepare}->($self) 556 ? $self->{on_prepare}->($self)
525 : () 557 : ()
526 } 558 }
527 ); 559 );
528 } 560 }
529 561
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547 579
548 $self->{_activity} = 580 $self->{_activity} =
549 $self->{_ractivity} = 581 $self->{_ractivity} =
550 $self->{_wactivity} = AE::now; 582 $self->{_wactivity} = AE::now;
551 583
584 $self->{read_size} ||= 2048;
585 $self->{max_read_size} = $self->{read_size}
586 if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
587
552 $self->timeout (delete $self->{timeout} ) if $self->{timeout}; 588 $self->timeout (delete $self->{timeout} ) if $self->{timeout};
553 $self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout}; 589 $self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
554 $self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout}; 590 $self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
555 591
556 $self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay}; 592 $self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
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559 $self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1); 595 $self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
560 596
561 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx}) 597 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
562 if $self->{tls}; 598 if $self->{tls};
563 599
564 $self->on_drain (delete $self->{on_drain}) if $self->{on_drain}; 600 $self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
565 601
566 $self->start_read 602 $self->start_read
567 if $self->{on_read} || @{ $self->{_queue} }; 603 if $self->{on_read} || @{ $self->{_queue} };
568 604
569 $self->_drain_wbuf; 605 $self->_drain_wbuf;
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645=cut 681=cut
646 682
647sub no_delay { 683sub no_delay {
648 $_[0]{no_delay} = $_[1]; 684 $_[0]{no_delay} = $_[1];
649 685
650 eval {
651 local $SIG{__DIE__};
652 setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1] 686 setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
653 if $_[0]{fh}; 687 if $_[0]{fh};
654 };
655} 688}
656 689
657=item $handle->keepalive ($boolean) 690=item $handle->keepalive ($boolean)
658 691
659Enables or disables the C<keepalive> setting (see constructor argument of 692Enables or disables the C<keepalive> setting (see constructor argument of
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727 760
728=item $handle->rbuf_max ($max_octets) 761=item $handle->rbuf_max ($max_octets)
729 762
730Configures the C<rbuf_max> setting (C<undef> disables it). 763Configures the C<rbuf_max> setting (C<undef> disables it).
731 764
765=item $handle->wbuf_max ($max_octets)
766
767Configures the C<wbuf_max> setting (C<undef> disables it).
768
732=cut 769=cut
733 770
734sub rbuf_max { 771sub rbuf_max {
735 $_[0]{rbuf_max} = $_[1]; 772 $_[0]{rbuf_max} = $_[1];
736} 773}
737 774
775sub wbuf_max {
776 $_[0]{wbuf_max} = $_[1];
777}
778
738############################################################################# 779#############################################################################
739 780
740=item $handle->timeout ($seconds) 781=item $handle->timeout ($seconds)
741 782
742=item $handle->rtimeout ($seconds) 783=item $handle->rtimeout ($seconds)
743 784
744=item $handle->wtimeout ($seconds) 785=item $handle->wtimeout ($seconds)
745 786
746Configures (or disables) the inactivity timeout. 787Configures (or disables) the inactivity timeout.
788
789The timeout will be checked instantly, so this method might destroy the
790handle before it returns.
747 791
748=item $handle->timeout_reset 792=item $handle->timeout_reset
749 793
750=item $handle->rtimeout_reset 794=item $handle->rtimeout_reset
751 795
… …
768 $_[0]{$on_timeout} = $_[1]; 812 $_[0]{$on_timeout} = $_[1];
769 }; 813 };
770 814
771 *$timeout = sub { 815 *$timeout = sub {
772 my ($self, $new_value) = @_; 816 my ($self, $new_value) = @_;
817
818 $new_value >= 0
819 or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
773 820
774 $self->{$timeout} = $new_value; 821 $self->{$timeout} = $new_value;
775 delete $self->{$tw}; &$cb; 822 delete $self->{$tw}; &$cb;
776 }; 823 };
777 824
… …
857 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf}); 904 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
858} 905}
859 906
860=item $handle->push_write ($data) 907=item $handle->push_write ($data)
861 908
862Queues the given scalar to be written. You can push as much data as you 909Queues the given scalar to be written. You can push as much data as
863want (only limited by the available memory), as C<AnyEvent::Handle> 910you want (only limited by the available memory and C<wbuf_max>), as
864buffers it independently of the kernel. 911C<AnyEvent::Handle> buffers it independently of the kernel.
865 912
866This method may invoke callbacks (and therefore the handle might be 913This method may invoke callbacks (and therefore the handle might be
867destroyed after it returns). 914destroyed after it returns).
868 915
869=cut 916=cut
… …
897 $cb->() unless $self->{autocork}; 944 $cb->() unless $self->{autocork};
898 945
899 # if still data left in wbuf, we need to poll 946 # if still data left in wbuf, we need to poll
900 $self->{_ww} = AE::io $self->{fh}, 1, $cb 947 $self->{_ww} = AE::io $self->{fh}, 1, $cb
901 if length $self->{wbuf}; 948 if length $self->{wbuf};
949
950 if (
951 defined $self->{wbuf_max}
952 && $self->{wbuf_max} < length $self->{wbuf}
953 ) {
954 $self->_error (Errno::ENOSPC, 1), return;
955 }
902 }; 956 };
903} 957}
904 958
905our %WH; 959our %WH;
906 960
… …
1041before it was actually written. One way to do that is to replace your 1095before it was actually written. One way to do that is to replace your
1042C<on_drain> handler by a callback that shuts down the socket (and set 1096C<on_drain> handler by a callback that shuts down the socket (and set
1043C<low_water_mark> to C<0>). This method is a shorthand for just that, and 1097C<low_water_mark> to C<0>). This method is a shorthand for just that, and
1044replaces the C<on_drain> callback with: 1098replaces the C<on_drain> callback with:
1045 1099
1046 sub { shutdown $_[0]{fh}, 1 } # for push_shutdown 1100 sub { shutdown $_[0]{fh}, 1 }
1047 1101
1048This simply shuts down the write side and signals an EOF condition to the 1102This simply shuts down the write side and signals an EOF condition to the
1049the peer. 1103the peer.
1050 1104
1051You can rely on the normal read queue and C<on_eof> handling 1105You can rely on the normal read queue and C<on_eof> handling
… …
1117partial message has been received so far), or change the read queue with 1171partial message has been received so far), or change the read queue with
1118e.g. C<push_read>. 1172e.g. C<push_read>.
1119 1173
1120In the more complex case, you want to queue multiple callbacks. In this 1174In the more complex case, you want to queue multiple callbacks. In this
1121case, AnyEvent::Handle will call the first queued callback each time new 1175case, AnyEvent::Handle will call the first queued callback each time new
1122data arrives (also the first time it is queued) and removes it when it has 1176data arrives (also the first time it is queued) and remove it when it has
1123done its job (see C<push_read>, below). 1177done its job (see C<push_read>, below).
1124 1178
1125This way you can, for example, push three line-reads, followed by reading 1179This way you can, for example, push three line-reads, followed by reading
1126a chunk of data, and AnyEvent::Handle will execute them in order. 1180a chunk of data, and AnyEvent::Handle will execute them in order.
1127 1181
… …
1272 $self->_drain_rbuf if $cb; 1326 $self->_drain_rbuf if $cb;
1273} 1327}
1274 1328
1275=item $handle->rbuf 1329=item $handle->rbuf
1276 1330
1277Returns the read buffer (as a modifiable lvalue). 1331Returns the read buffer (as a modifiable lvalue). You can also access the
1332read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
1333much faster, and no less clean).
1278 1334
1279You can access the read buffer directly as the C<< ->{rbuf} >> 1335The only operation allowed on the read buffer (apart from looking at it)
1280member, if you want. However, the only operation allowed on the 1336is removing data from its beginning. Otherwise modifying or appending to
1281read buffer (apart from looking at it) is removing data from its 1337it is not allowed and will lead to hard-to-track-down bugs.
1282beginning. Otherwise modifying or appending to it is not allowed and will
1283lead to hard-to-track-down bugs.
1284 1338
1285NOTE: The read buffer should only be used or modified if the C<on_read>, 1339NOTE: The read buffer should only be used or modified in the C<on_read>
1286C<push_read> or C<unshift_read> methods are used. The other read methods 1340callback or when C<push_read> or C<unshift_read> are used with a single
1287automatically manage the read buffer. 1341callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
1342will manage the read buffer on their own.
1288 1343
1289=cut 1344=cut
1290 1345
1291sub rbuf : lvalue { 1346sub rbuf : lvalue {
1292 $_[0]{rbuf} 1347 $_[0]{rbuf}
… …
1343 my $cb = pop; 1398 my $cb = pop;
1344 1399
1345 if (@_) { 1400 if (@_) {
1346 my $type = shift; 1401 my $type = shift;
1347 1402
1403 $cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
1348 $cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read") 1404 or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
1349 ->($self, $cb, @_); 1405 ->($self, $cb, @_);
1350 } 1406 }
1351 1407
1352 unshift @{ $self->{_queue} }, $cb; 1408 unshift @{ $self->{_queue} }, $cb;
1353 $self->_drain_rbuf; 1409 $self->_drain_rbuf;
… …
1461the receive buffer when neither C<$accept> nor C<$reject> match, 1517the receive buffer when neither C<$accept> nor C<$reject> match,
1462and everything preceding and including the match will be accepted 1518and everything preceding and including the match will be accepted
1463unconditionally. This is useful to skip large amounts of data that you 1519unconditionally. This is useful to skip large amounts of data that you
1464know cannot be matched, so that the C<$accept> or C<$reject> regex do not 1520know cannot be matched, so that the C<$accept> or C<$reject> regex do not
1465have to start matching from the beginning. This is purely an optimisation 1521have to start matching from the beginning. This is purely an optimisation
1466and is usually worth only when you expect more than a few kilobytes. 1522and is usually worth it only when you expect more than a few kilobytes.
1467 1523
1468Example: expect a http header, which ends at C<\015\012\015\012>. Since we 1524Example: expect a http header, which ends at C<\015\012\015\012>. Since we
1469expect the header to be very large (it isn't in practise, but...), we use 1525expect the header to be very large (it isn't in practice, but...), we use
1470a skip regex to skip initial portions. The skip regex is tricky in that 1526a skip regex to skip initial portions. The skip regex is tricky in that
1471it only accepts something not ending in either \015 or \012, as these are 1527it only accepts something not ending in either \015 or \012, as these are
1472required for the accept regex. 1528required for the accept regex.
1473 1529
1474 $handle->push_read (regex => 1530 $handle->push_read (regex =>
… …
1725Note that AnyEvent::Handle will automatically C<start_read> for you when 1781Note that AnyEvent::Handle will automatically C<start_read> for you when
1726you change the C<on_read> callback or push/unshift a read callback, and it 1782you change the C<on_read> callback or push/unshift a read callback, and it
1727will automatically C<stop_read> for you when neither C<on_read> is set nor 1783will automatically C<stop_read> for you when neither C<on_read> is set nor
1728there are any read requests in the queue. 1784there are any read requests in the queue.
1729 1785
1730These methods will have no effect when in TLS mode (as TLS doesn't support 1786In older versions of this module (<= 5.3), these methods had no effect,
1731half-duplex connections). 1787as TLS does not support half-duplex connections. In current versions they
1788work as expected, as this behaviour is required to avoid certain resource
1789attacks, where the program would be forced to read (and buffer) arbitrary
1790amounts of data before being able to send some data. The drawback is that
1791some readings of the the SSL/TLS specifications basically require this
1792attack to be working, as SSL/TLS implementations might stall sending data
1793during a rehandshake.
1794
1795As a guideline, during the initial handshake, you should not stop reading,
1796and as a client, it might cause problems, depending on your applciation.
1732 1797
1733=cut 1798=cut
1734 1799
1735sub stop_read { 1800sub stop_read {
1736 my ($self) = @_; 1801 my ($self) = @_;
1737 1802
1738 delete $self->{_rw} unless $self->{tls}; 1803 delete $self->{_rw};
1739} 1804}
1740 1805
1741sub start_read { 1806sub start_read {
1742 my ($self) = @_; 1807 my ($self) = @_;
1743 1808
1744 unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) { 1809 unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
1745 Scalar::Util::weaken $self; 1810 Scalar::Util::weaken $self;
1746 1811
1747 $self->{_rw} = AE::io $self->{fh}, 0, sub { 1812 $self->{_rw} = AE::io $self->{fh}, 0, sub {
1748 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf}); 1813 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1749 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf; 1814 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
1750 1815
1751 if ($len > 0) { 1816 if ($len > 0) {
1752 $self->{_activity} = $self->{_ractivity} = AE::now; 1817 $self->{_activity} = $self->{_ractivity} = AE::now;
1753 1818
1754 if ($self->{tls}) { 1819 if ($self->{tls}) {
1755 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf); 1820 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1756 1821
1757 &_dotls ($self); 1822 &_dotls ($self);
1758 } else { 1823 } else {
1759 $self->_drain_rbuf; 1824 $self->_drain_rbuf;
1825 }
1826
1827 if ($len == $self->{read_size}) {
1828 $self->{read_size} *= 2;
1829 $self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
1830 if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
1760 } 1831 }
1761 1832
1762 } elsif (defined $len) { 1833 } elsif (defined $len) {
1763 delete $self->{_rw}; 1834 delete $self->{_rw};
1764 $self->{_eof} = 1; 1835 $self->{_eof} = 1;
… …
1874context in C<< $handle->{tls_ctx} >> after this call and can be used or 1945context in C<< $handle->{tls_ctx} >> after this call and can be used or
1875changed to your liking. Note that the handshake might have already started 1946changed to your liking. Note that the handshake might have already started
1876when this function returns. 1947when this function returns.
1877 1948
1878Due to bugs in OpenSSL, it might or might not be possible to do multiple 1949Due to bugs in OpenSSL, it might or might not be possible to do multiple
1879handshakes on the same stream. Best do not attempt to use the stream after 1950handshakes on the same stream. It is best to not attempt to use the
1880stopping TLS. 1951stream after stopping TLS.
1881 1952
1882This method may invoke callbacks (and therefore the handle might be 1953This method may invoke callbacks (and therefore the handle might be
1883destroyed after it returns). 1954destroyed after it returns).
1884 1955
1885=cut 1956=cut
… …
1987 if $self->{tls} > 0; 2058 if $self->{tls} > 0;
1988 2059
1989 delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)}; 2060 delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
1990} 2061}
1991 2062
2063=item $handle->resettls
2064
2065This rarely-used method simply resets and TLS state on the handle, usually
2066causing data loss.
2067
2068One case where it may be useful is when you want to skip over the data in
2069the stream but you are not interested in interpreting it, so data loss is
2070no concern.
2071
2072=cut
2073
2074*resettls = \&_freetls;
2075
1992sub DESTROY { 2076sub DESTROY {
1993 my ($self) = @_; 2077 my ($self) = @_;
1994 2078
1995 &_freetls; 2079 &_freetls;
1996 2080
… …
2005 push @linger, AE::io $fh, 1, sub { 2089 push @linger, AE::io $fh, 1, sub {
2006 my $len = syswrite $fh, $wbuf, length $wbuf; 2090 my $len = syswrite $fh, $wbuf, length $wbuf;
2007 2091
2008 if ($len > 0) { 2092 if ($len > 0) {
2009 substr $wbuf, 0, $len, ""; 2093 substr $wbuf, 0, $len, "";
2010 } else { 2094 } elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
2011 @linger = (); # end 2095 @linger = (); # end
2012 } 2096 }
2013 }; 2097 };
2014 push @linger, AE::timer $linger, 0, sub { 2098 push @linger, AE::timer $linger, 0, sub {
2015 @linger = (); 2099 @linger = ();
… …
2111 2195
2112It is only safe to "forget" the reference inside EOF or error callbacks, 2196It is only safe to "forget" the reference inside EOF or error callbacks,
2113from within all other callbacks, you need to explicitly call the C<< 2197from within all other callbacks, you need to explicitly call the C<<
2114->destroy >> method. 2198->destroy >> method.
2115 2199
2200=item Why is my C<on_eof> callback never called?
2201
2202Probably because your C<on_error> callback is being called instead: When
2203you have outstanding requests in your read queue, then an EOF is
2204considered an error as you clearly expected some data.
2205
2206To avoid this, make sure you have an empty read queue whenever your handle
2207is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
2208an C<on_read> handler that simply pushes the first read requests in the
2209queue.
2210
2211See also the next question, which explains this in a bit more detail.
2212
2213=item How can I serve requests in a loop?
2214
2215Most protocols consist of some setup phase (authentication for example)
2216followed by a request handling phase, where the server waits for requests
2217and handles them, in a loop.
2218
2219There are two important variants: The first (traditional, better) variant
2220handles requests until the server gets some QUIT command, causing it to
2221close the connection first (highly desirable for a busy TCP server). A
2222client dropping the connection is an error, which means this variant can
2223detect an unexpected detection close.
2224
2225To handle this case, always make sure you have a on-empty read queue, by
2226pushing the "read request start" handler on it:
2227
2228 # we assume a request starts with a single line
2229 my @start_request; @start_request = (line => sub {
2230 my ($hdl, $line) = @_;
2231
2232 ... handle request
2233
2234 # push next request read, possibly from a nested callback
2235 $hdl->push_read (@start_request);
2236 });
2237
2238 # auth done, now go into request handling loop
2239 # now push the first @start_request
2240 $hdl->push_read (@start_request);
2241
2242By always having an outstanding C<push_read>, the handle always expects
2243some data and raises the C<EPIPE> error when the connction is dropped
2244unexpectedly.
2245
2246The second variant is a protocol where the client can drop the connection
2247at any time. For TCP, this means that the server machine may run out of
2248sockets easier, and in general, it means you cnanot distinguish a protocl
2249failure/client crash from a normal connection close. Nevertheless, these
2250kinds of protocols are common (and sometimes even the best solution to the
2251problem).
2252
2253Having an outstanding read request at all times is possible if you ignore
2254C<EPIPE> errors, but this doesn't help with when the client drops the
2255connection during a request, which would still be an error.
2256
2257A better solution is to push the initial request read in an C<on_read>
2258callback. This avoids an error, as when the server doesn't expect data
2259(i.e. is idly waiting for the next request, an EOF will not raise an
2260error, but simply result in an C<on_eof> callback. It is also a bit slower
2261and simpler:
2262
2263 # auth done, now go into request handling loop
2264 $hdl->on_read (sub {
2265 my ($hdl) = @_;
2266
2267 # called each time we receive data but the read queue is empty
2268 # simply start read the request
2269
2270 $hdl->push_read (line => sub {
2271 my ($hdl, $line) = @_;
2272
2273 ... handle request
2274
2275 # do nothing special when the request has been handled, just
2276 # let the request queue go empty.
2277 });
2278 });
2279
2116=item I get different callback invocations in TLS mode/Why can't I pause 2280=item I get different callback invocations in TLS mode/Why can't I pause
2117reading? 2281reading?
2118 2282
2119Unlike, say, TCP, TLS connections do not consist of two independent 2283Unlike, say, TCP, TLS connections do not consist of two independent
2120communication channels, one for each direction. Or put differently. The 2284communication channels, one for each direction. Or put differently, the
2121read and write directions are not independent of each other: you cannot 2285read and write directions are not independent of each other: you cannot
2122write data unless you are also prepared to read, and vice versa. 2286write data unless you are also prepared to read, and vice versa.
2123 2287
2124This can mean than, in TLS mode, you might get C<on_error> or C<on_eof> 2288This means that, in TLS mode, you might get C<on_error> or C<on_eof>
2125callback invocations when you are not expecting any read data - the reason 2289callback invocations when you are not expecting any read data - the reason
2126is that AnyEvent::Handle always reads in TLS mode. 2290is that AnyEvent::Handle always reads in TLS mode.
2127 2291
2128During the connection, you have to make sure that you always have a 2292During the connection, you have to make sure that you always have a
2129non-empty read-queue, or an C<on_read> watcher. At the end of the 2293non-empty read-queue, or an C<on_read> watcher. At the end of the
… …
2143 my $data = delete $_[0]{rbuf}; 2307 my $data = delete $_[0]{rbuf};
2144 }); 2308 });
2145 2309
2146The reason to use C<on_error> is that TCP connections, due to latencies 2310The reason to use C<on_error> is that TCP connections, due to latencies
2147and packets loss, might get closed quite violently with an error, when in 2311and packets loss, might get closed quite violently with an error, when in
2148fact, all data has been received. 2312fact all data has been received.
2149 2313
2150It is usually better to use acknowledgements when transferring data, 2314It is usually better to use acknowledgements when transferring data,
2151to make sure the other side hasn't just died and you got the data 2315to make sure the other side hasn't just died and you got the data
2152intact. This is also one reason why so many internet protocols have an 2316intact. This is also one reason why so many internet protocols have an
2153explicit QUIT command. 2317explicit QUIT command.
… …
2170consider using C<< ->push_shutdown >> instead. 2334consider using C<< ->push_shutdown >> instead.
2171 2335
2172=item I want to contact a TLS/SSL server, I don't care about security. 2336=item I want to contact a TLS/SSL server, I don't care about security.
2173 2337
2174If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS, 2338If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
2175simply connect to it and then create the AnyEvent::Handle with the C<tls> 2339connect to it and then create the AnyEvent::Handle with the C<tls>
2176parameter: 2340parameter:
2177 2341
2178 tcp_connect $host, $port, sub { 2342 tcp_connect $host, $port, sub {
2179 my ($fh) = @_; 2343 my ($fh) = @_;
2180 2344
… …
2280 2444
2281=item * all members not documented here and not prefixed with an underscore 2445=item * all members not documented here and not prefixed with an underscore
2282are free to use in subclasses. 2446are free to use in subclasses.
2283 2447
2284Of course, new versions of AnyEvent::Handle may introduce more "public" 2448Of course, new versions of AnyEvent::Handle may introduce more "public"
2285member variables, but thats just life, at least it is documented. 2449member variables, but that's just life. At least it is documented.
2286 2450
2287=back 2451=back
2288 2452
2289=head1 AUTHOR 2453=head1 AUTHOR
2290 2454

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