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Revision 1.196 by root, Tue Jun 8 10:04:17 2010 UTC vs.
Revision 1.220 by root, Sun Jul 24 13:10:43 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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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<$!> set to C<EPIPE>).
201 205
202Note that, unlike requests in the read queue, an C<on_read> callback 206Note that, unlike requests in the read queue, an C<on_read> callback
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221set, then a fatal error will be raised with C<$!> 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
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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 of each
249of 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:
250C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks 255C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
251C<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
252C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>. 257C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
253 258
254Note 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
255any outstanding read or write requests: If you plan to keep the connection 260outstanding read or write requests: If you plan to keep the connection
256idle then you should disable the timout temporarily or ignore the timeout 261idle then you should disable the timeout temporarily or ignore the
257in the C<on_timeout> callback, in which case AnyEvent::Handle will simply 262timeout in the corresponding C<on_timeout> callback, in which case
258restart the timeout. 263AnyEvent::Handle will simply restart the timeout.
259 264
260Zero (the default) disables this timeout. 265Zero (the default) disables the corresponding timeout.
261 266
262=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)
263 272
264Called whenever the inactivity timeout passes. If you return from this 273Called whenever the inactivity timeout passes. If you return from this
265callback, 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,
266so this condition is not fatal in any way. 275so this condition is not fatal in any way.
267 276
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275be 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
276(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
277amount 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
278isn't finished). 287isn't finished).
279 288
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
280=item autocork => <boolean> 304=item autocork => <boolean>
281 305
282When disabled (the default), then C<push_write> will try to immediately 306When disabled (the default), C<push_write> will try to immediately
283write 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
284a 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
285be inefficient if you write multiple small chunks (on the wire, this 309be inefficient if you write multiple small chunks (on the wire, this
286disadvantage is usually avoided by your kernel's nagle algorithm, see 310disadvantage is usually avoided by your kernel's nagle algorithm, see
287C<no_delay>, but this option can save costly syscalls). 311C<no_delay>, but this option can save costly syscalls).
288 312
289When enabled, then writes will always be queued till the next event loop 313When enabled, writes will always be queued till the next event loop
290iteration. This is efficient when you do many small writes per iteration, 314iteration. 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 315but less efficient when you do a single write only per iteration (or when
292the write buffer often is full). It also increases write latency. 316the write buffer often is full). It also increases write latency.
293 317
294=item no_delay => <boolean> 318=item no_delay => <boolean>
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298the Nagle algorithm, and usually it is beneficial. 322the Nagle algorithm, and usually it is beneficial.
299 323
300In 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
301accomplishd by setting this option to a true value. 325accomplishd by setting this option to a true value.
302 326
303The default is your opertaing system's default behaviour (most likely 327The default is your operating system's default behaviour (most likely
304enabled), this option explicitly enables or disables it, if possible. 328enabled). This option explicitly enables or disables it, if possible.
305 329
306=item keepalive => <boolean> 330=item keepalive => <boolean>
307 331
308Enables (default disable) the SO_KEEPALIVE option on the stream socket: 332Enables (default disable) the SO_KEEPALIVE option on the stream socket:
309normally, TCP connections have no time-out once established, so TCP 333normally, TCP connections have no time-out once established, so TCP
310connections, once established, can stay alive forever even when the other 334connections, 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 335side 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 336TCP connections when the other side becomes unreachable. While the default
313is OS-dependent, TCP keepalives usually kick in after around two hours, 337is 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 338and, if the other side doesn't reply, take down the TCP connection some 10
315to 15 minutes later. 339to 15 minutes later.
316 340
317It 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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335already 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
336from most attacks. 360from most attacks.
337 361
338=item read_size => <bytes> 362=item read_size => <bytes>
339 363
340The 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
341try to read during each loop iteration, which affects memory 365read during each loop iteration. Each handle object will consume at least
342requirements). 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.
343 375
344=item low_water_mark => <bytes> 376=item low_water_mark => <bytes>
345 377
346Sets 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
347buffer: 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
348considered empty. 380considered empty.
349 381
350Sometimes it can be beneficial (for performance reasons) to add data to 382Sometimes 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 383the 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 384the operating system kernel usually buffers data as well, so the default
353is good in almost all cases. 385is good in almost all cases.
354 386
355=item linger => <seconds> 387=item linger => <seconds>
356 388
357If non-zero (default: C<3600>), then the destructor of the 389If this is non-zero (default: C<3600>), the destructor of the
358AnyEvent::Handle object will check whether there is still outstanding 390AnyEvent::Handle object will check whether there is still outstanding
359write 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
360socket. No errors will be reported (this mostly matches how the operating 392socket. No errors will be reported (this mostly matches how the operating
361system treats outstanding data at socket close time). 393system treats outstanding data at socket close time).
362 394
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369A string used to identify the remote site - usually the DNS hostname 401A string used to identify the remote site - usually the DNS hostname
370(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.
371 403
372Apart 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
373peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This 405peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
374verification will be skipped when C<peername> is not specified or 406verification will be skipped when C<peername> is not specified or is
375C<undef>. 407C<undef>.
376 408
377=item tls => "accept" | "connect" | Net::SSLeay::SSL object 409=item tls => "accept" | "connect" | Net::SSLeay::SSL object
378 410
379When 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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405B<IMPORTANT:> since Net::SSLeay "objects" are really only integers, 437B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
406passing 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
407happens 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
408segmentation fault. 440segmentation fault.
409 441
410See 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.
411 443
412=item tls_ctx => $anyevent_tls 444=item tls_ctx => $anyevent_tls
413 445
414Use 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
415(unless a connection object was specified directly). If this parameter is 447(unless a connection object was specified directly). If this
416missing, 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>.
417 450
418Instead 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
419=> 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
420new TLS context object. 453new TLS context object.
421 454
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430 463
431TLS 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
432callback 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>.
433 466
434Without this callback, handshake failures lead to C<on_error> being 467Without this callback, handshake failures lead to C<on_error> being
435called, as normal. 468called as usual.
436 469
437Note 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
438need 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
439then call C<< ->starttls >> again. 472then call C<< ->starttls >> again.
440 473
441=item on_stoptls => $cb->($handle) 474=item on_stoptls => $cb->($handle)
442 475
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490 $self->{connect}[0], 523 $self->{connect}[0],
491 $self->{connect}[1], 524 $self->{connect}[1],
492 sub { 525 sub {
493 my ($fh, $host, $port, $retry) = @_; 526 my ($fh, $host, $port, $retry) = @_;
494 527
528 delete $self->{_connect}; # no longer needed
529
495 if ($fh) { 530 if ($fh) {
496 $self->{fh} = $fh; 531 $self->{fh} = $fh;
497 532
498 delete $self->{_skip_drain_rbuf}; 533 delete $self->{_skip_drain_rbuf};
499 $self->_start; 534 $self->_start;
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506 }); 541 });
507 542
508 } else { 543 } else {
509 if ($self->{on_connect_error}) { 544 if ($self->{on_connect_error}) {
510 $self->{on_connect_error}($self, "$!"); 545 $self->{on_connect_error}($self, "$!");
511 $self->destroy; 546 $self->destroy if $self;
512 } else { 547 } else {
513 $self->_error ($!, 1); 548 $self->_error ($!, 1);
514 } 549 }
515 } 550 }
516 }, 551 },
517 sub { 552 sub {
518 local $self->{fh} = $_[0]; 553 local $self->{fh} = $_[0];
519 554
520 $self->{on_prepare} 555 $self->{on_prepare}
521 ? $self->{on_prepare}->($self) 556 ? $self->{on_prepare}->($self)
522 : () 557 : ()
523 } 558 }
524 ); 559 );
525 } 560 }
526 561
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544 579
545 $self->{_activity} = 580 $self->{_activity} =
546 $self->{_ractivity} = 581 $self->{_ractivity} =
547 $self->{_wactivity} = AE::now; 582 $self->{_wactivity} = AE::now;
548 583
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
549 $self->timeout (delete $self->{timeout} ) if $self->{timeout}; 588 $self->timeout (delete $self->{timeout} ) if $self->{timeout};
550 $self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout}; 589 $self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
551 $self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout}; 590 $self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
552 591
553 $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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556 $self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1); 595 $self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
557 596
558 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx}) 597 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
559 if $self->{tls}; 598 if $self->{tls};
560 599
561 $self->on_drain (delete $self->{on_drain}) if $self->{on_drain}; 600 $self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
562 601
563 $self->start_read 602 $self->start_read
564 if $self->{on_read} || @{ $self->{_queue} }; 603 if $self->{on_read} || @{ $self->{_queue} };
565 604
566 $self->_drain_wbuf; 605 $self->_drain_wbuf;
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642=cut 681=cut
643 682
644sub no_delay { 683sub no_delay {
645 $_[0]{no_delay} = $_[1]; 684 $_[0]{no_delay} = $_[1];
646 685
647 eval {
648 local $SIG{__DIE__};
649 setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1] 686 setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
650 if $_[0]{fh}; 687 if $_[0]{fh};
651 };
652} 688}
653 689
654=item $handle->keepalive ($boolean) 690=item $handle->keepalive ($boolean)
655 691
656Enables 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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724 760
725=item $handle->rbuf_max ($max_octets) 761=item $handle->rbuf_max ($max_octets)
726 762
727Configures the C<rbuf_max> setting (C<undef> disables it). 763Configures the C<rbuf_max> setting (C<undef> disables it).
728 764
765=item $handle->wbuf_max ($max_octets)
766
767Configures the C<wbuf_max> setting (C<undef> disables it).
768
729=cut 769=cut
730 770
731sub rbuf_max { 771sub rbuf_max {
732 $_[0]{rbuf_max} = $_[1]; 772 $_[0]{rbuf_max} = $_[1];
733} 773}
734 774
775sub wbuf_max {
776 $_[0]{wbuf_max} = $_[1];
777}
778
735############################################################################# 779#############################################################################
736 780
737=item $handle->timeout ($seconds) 781=item $handle->timeout ($seconds)
738 782
739=item $handle->rtimeout ($seconds) 783=item $handle->rtimeout ($seconds)
740 784
741=item $handle->wtimeout ($seconds) 785=item $handle->wtimeout ($seconds)
742 786
743Configures (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.
744 791
745=item $handle->timeout_reset 792=item $handle->timeout_reset
746 793
747=item $handle->rtimeout_reset 794=item $handle->rtimeout_reset
748 795
… …
765 $_[0]{$on_timeout} = $_[1]; 812 $_[0]{$on_timeout} = $_[1];
766 }; 813 };
767 814
768 *$timeout = sub { 815 *$timeout = sub {
769 my ($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";
770 820
771 $self->{$timeout} = $new_value; 821 $self->{$timeout} = $new_value;
772 delete $self->{$tw}; &$cb; 822 delete $self->{$tw}; &$cb;
773 }; 823 };
774 824
… …
854 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});
855} 905}
856 906
857=item $handle->push_write ($data) 907=item $handle->push_write ($data)
858 908
859Queues 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
860want (only limited by the available memory), as C<AnyEvent::Handle> 910you want (only limited by the available memory and C<wbuf_max>), as
861buffers it independently of the kernel. 911C<AnyEvent::Handle> buffers it independently of the kernel.
862 912
863This method may invoke callbacks (and therefore the handle might be 913This method may invoke callbacks (and therefore the handle might be
864destroyed after it returns). 914destroyed after it returns).
865 915
866=cut 916=cut
… …
894 $cb->() unless $self->{autocork}; 944 $cb->() unless $self->{autocork};
895 945
896 # if still data left in wbuf, we need to poll 946 # if still data left in wbuf, we need to poll
897 $self->{_ww} = AE::io $self->{fh}, 1, $cb 947 $self->{_ww} = AE::io $self->{fh}, 1, $cb
898 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 }
899 }; 956 };
900} 957}
901 958
902our %WH; 959our %WH;
903 960
… …
933 990
934Instead of formatting your data yourself, you can also let this module 991Instead of formatting your data yourself, you can also let this module
935do the job by specifying a type and type-specific arguments. You 992do the job by specifying a type and type-specific arguments. You
936can also specify the (fully qualified) name of a package, in which 993can also specify the (fully qualified) name of a package, in which
937case AnyEvent tries to load the package and then expects to find the 994case AnyEvent tries to load the package and then expects to find the
938C<anyevent_read_type> function inside (see "custom write types", below). 995C<anyevent_write_type> function inside (see "custom write types", below).
939 996
940Predefined types are (if you have ideas for additional types, feel free to 997Predefined types are (if you have ideas for additional types, feel free to
941drop by and tell us): 998drop by and tell us):
942 999
943=over 4 1000=over 4
… …
1038before 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
1039C<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
1040C<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
1041replaces the C<on_drain> callback with: 1098replaces the C<on_drain> callback with:
1042 1099
1043 sub { shutdown $_[0]{fh}, 1 } # for push_shutdown 1100 sub { shutdown $_[0]{fh}, 1 }
1044 1101
1045This 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
1046the peer. 1103the peer.
1047 1104
1048You 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
… …
1107ways, the "simple" way, using only C<on_read> and the "complex" way, using 1164ways, the "simple" way, using only C<on_read> and the "complex" way, using
1108a queue. 1165a queue.
1109 1166
1110In the simple case, you just install an C<on_read> callback and whenever 1167In the simple case, you just install an C<on_read> callback and whenever
1111new data arrives, it will be called. You can then remove some data (if 1168new data arrives, it will be called. You can then remove some data (if
1112enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna 1169enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
1113leave the data there if you want to accumulate more (e.g. when only a 1170leave the data there if you want to accumulate more (e.g. when only a
1114partial message has been received so far). 1171partial message has been received so far), or change the read queue with
1172e.g. C<push_read>.
1115 1173
1116In 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
1117case, AnyEvent::Handle will call the first queued callback each time new 1175case, AnyEvent::Handle will call the first queued callback each time new
1118data 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
1119done its job (see C<push_read>, below). 1177done its job (see C<push_read>, below).
1120 1178
1121This 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
1122a chunk of data, and AnyEvent::Handle will execute them in order. 1180a chunk of data, and AnyEvent::Handle will execute them in order.
1123 1181
… …
1268 $self->_drain_rbuf if $cb; 1326 $self->_drain_rbuf if $cb;
1269} 1327}
1270 1328
1271=item $handle->rbuf 1329=item $handle->rbuf
1272 1330
1273Returns 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).
1274 1334
1275You can access the read buffer directly as the C<< ->{rbuf} >> 1335The only operation allowed on the read buffer (apart from looking at it)
1276member, if you want. However, the only operation allowed on the 1336is removing data from its beginning. Otherwise modifying or appending to
1277read buffer (apart from looking at it) is removing data from its 1337it is not allowed and will lead to hard-to-track-down bugs.
1278beginning. Otherwise modifying or appending to it is not allowed and will
1279lead to hard-to-track-down bugs.
1280 1338
1281NOTE: 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>
1282C<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
1283automatically 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.
1284 1343
1285=cut 1344=cut
1286 1345
1287sub rbuf : lvalue { 1346sub rbuf : lvalue {
1288 $_[0]{rbuf} 1347 $_[0]{rbuf}
… …
1339 my $cb = pop; 1398 my $cb = pop;
1340 1399
1341 if (@_) { 1400 if (@_) {
1342 my $type = shift; 1401 my $type = shift;
1343 1402
1403 $cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
1344 $cb = ($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")
1345 ->($self, $cb, @_); 1405 ->($self, $cb, @_);
1346 } 1406 }
1347 1407
1348 unshift @{ $self->{_queue} }, $cb; 1408 unshift @{ $self->{_queue} }, $cb;
1349 $self->_drain_rbuf; 1409 $self->_drain_rbuf;
… …
1457the receive buffer when neither C<$accept> nor C<$reject> match, 1517the receive buffer when neither C<$accept> nor C<$reject> match,
1458and everything preceding and including the match will be accepted 1518and everything preceding and including the match will be accepted
1459unconditionally. This is useful to skip large amounts of data that you 1519unconditionally. This is useful to skip large amounts of data that you
1460know cannot be matched, so that the C<$accept> or C<$reject> regex do not 1520know cannot be matched, so that the C<$accept> or C<$reject> regex do not
1461have to start matching from the beginning. This is purely an optimisation 1521have to start matching from the beginning. This is purely an optimisation
1462and 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.
1463 1523
1464Example: 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
1465expect 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
1466a 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
1467it 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
1468required for the accept regex. 1528required for the accept regex.
1469 1529
1470 $handle->push_read (regex => 1530 $handle->push_read (regex =>
… …
1483 1543
1484 sub { 1544 sub {
1485 # accept 1545 # accept
1486 if ($$rbuf =~ $accept) { 1546 if ($$rbuf =~ $accept) {
1487 $data .= substr $$rbuf, 0, $+[0], ""; 1547 $data .= substr $$rbuf, 0, $+[0], "";
1488 $cb->($self, $data); 1548 $cb->($_[0], $data);
1489 return 1; 1549 return 1;
1490 } 1550 }
1491 1551
1492 # reject 1552 # reject
1493 if ($reject && $$rbuf =~ $reject) { 1553 if ($reject && $$rbuf =~ $reject) {
1494 $self->_error (Errno::EBADMSG); 1554 $_[0]->_error (Errno::EBADMSG);
1495 } 1555 }
1496 1556
1497 # skip 1557 # skip
1498 if ($skip && $$rbuf =~ $skip) { 1558 if ($skip && $$rbuf =~ $skip) {
1499 $data .= substr $$rbuf, 0, $+[0], ""; 1559 $data .= substr $$rbuf, 0, $+[0], "";
… …
1515 my ($self, $cb) = @_; 1575 my ($self, $cb) = @_;
1516 1576
1517 sub { 1577 sub {
1518 unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) { 1578 unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
1519 if ($_[0]{rbuf} =~ /[^0-9]/) { 1579 if ($_[0]{rbuf} =~ /[^0-9]/) {
1520 $self->_error (Errno::EBADMSG); 1580 $_[0]->_error (Errno::EBADMSG);
1521 } 1581 }
1522 return; 1582 return;
1523 } 1583 }
1524 1584
1525 my $len = $1; 1585 my $len = $1;
1526 1586
1527 $self->unshift_read (chunk => $len, sub { 1587 $_[0]->unshift_read (chunk => $len, sub {
1528 my $string = $_[1]; 1588 my $string = $_[1];
1529 $_[0]->unshift_read (chunk => 1, sub { 1589 $_[0]->unshift_read (chunk => 1, sub {
1530 if ($_[1] eq ",") { 1590 if ($_[1] eq ",") {
1531 $cb->($_[0], $string); 1591 $cb->($_[0], $string);
1532 } else { 1592 } else {
1533 $self->_error (Errno::EBADMSG); 1593 $_[0]->_error (Errno::EBADMSG);
1534 } 1594 }
1535 }); 1595 });
1536 }); 1596 });
1537 1597
1538 1 1598 1
… …
1611 1671
1612 my $data; 1672 my $data;
1613 my $rbuf = \$self->{rbuf}; 1673 my $rbuf = \$self->{rbuf};
1614 1674
1615 sub { 1675 sub {
1616 my $ref = eval { $json->incr_parse ($self->{rbuf}) }; 1676 my $ref = eval { $json->incr_parse ($_[0]{rbuf}) };
1617 1677
1618 if ($ref) { 1678 if ($ref) {
1619 $self->{rbuf} = $json->incr_text; 1679 $_[0]{rbuf} = $json->incr_text;
1620 $json->incr_text = ""; 1680 $json->incr_text = "";
1621 $cb->($self, $ref); 1681 $cb->($_[0], $ref);
1622 1682
1623 1 1683 1
1624 } elsif ($@) { 1684 } elsif ($@) {
1625 # error case 1685 # error case
1626 $json->incr_skip; 1686 $json->incr_skip;
1627 1687
1628 $self->{rbuf} = $json->incr_text; 1688 $_[0]{rbuf} = $json->incr_text;
1629 $json->incr_text = ""; 1689 $json->incr_text = "";
1630 1690
1631 $self->_error (Errno::EBADMSG); 1691 $_[0]->_error (Errno::EBADMSG);
1632 1692
1633 () 1693 ()
1634 } else { 1694 } else {
1635 $self->{rbuf} = ""; 1695 $_[0]{rbuf} = "";
1636 1696
1637 () 1697 ()
1638 } 1698 }
1639 } 1699 }
1640}; 1700};
… …
1673 # read remaining chunk 1733 # read remaining chunk
1674 $_[0]->unshift_read (chunk => $len, sub { 1734 $_[0]->unshift_read (chunk => $len, sub {
1675 if (my $ref = eval { Storable::thaw ($_[1]) }) { 1735 if (my $ref = eval { Storable::thaw ($_[1]) }) {
1676 $cb->($_[0], $ref); 1736 $cb->($_[0], $ref);
1677 } else { 1737 } else {
1678 $self->_error (Errno::EBADMSG); 1738 $_[0]->_error (Errno::EBADMSG);
1679 } 1739 }
1680 }); 1740 });
1681 } 1741 }
1682 1742
1683 1 1743 1
… …
1721Note that AnyEvent::Handle will automatically C<start_read> for you when 1781Note that AnyEvent::Handle will automatically C<start_read> for you when
1722you change the C<on_read> callback or push/unshift a read callback, and it 1782you change the C<on_read> callback or push/unshift a read callback, and it
1723will automatically C<stop_read> for you when neither C<on_read> is set nor 1783will automatically C<stop_read> for you when neither C<on_read> is set nor
1724there are any read requests in the queue. 1784there are any read requests in the queue.
1725 1785
1726These methods will have no effect when in TLS mode (as TLS doesn't support 1786In older versions of this module (<= 5.3), these methods had no effect,
1727half-duplex connections). 1787as TLS does not support half-duplex connections. In current versions they
1788work as expected, as this behaviour is required to avoid certain resource
1789attacks, where the program would be forced to read (and buffer) arbitrary
1790amounts of data before being able to send some data. The drawback is that
1791some readings of the the SSL/TLS specifications basically require this
1792attack to be working, as SSL/TLS implementations might stall sending data
1793during a rehandshake.
1794
1795As a guideline, during the initial handshake, you should not stop reading,
1796and as a client, it might cause problems, depending on your applciation.
1728 1797
1729=cut 1798=cut
1730 1799
1731sub stop_read { 1800sub stop_read {
1732 my ($self) = @_; 1801 my ($self) = @_;
1733 1802
1734 delete $self->{_rw} unless $self->{tls}; 1803 delete $self->{_rw};
1735} 1804}
1736 1805
1737sub start_read { 1806sub start_read {
1738 my ($self) = @_; 1807 my ($self) = @_;
1739 1808
1740 unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) { 1809 unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
1741 Scalar::Util::weaken $self; 1810 Scalar::Util::weaken $self;
1742 1811
1743 $self->{_rw} = AE::io $self->{fh}, 0, sub { 1812 $self->{_rw} = AE::io $self->{fh}, 0, sub {
1744 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf}); 1813 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1745 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf; 1814 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
1746 1815
1747 if ($len > 0) { 1816 if ($len > 0) {
1748 $self->{_activity} = $self->{_ractivity} = AE::now; 1817 $self->{_activity} = $self->{_ractivity} = AE::now;
1749 1818
1750 if ($self->{tls}) { 1819 if ($self->{tls}) {
1751 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf); 1820 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1752 1821
1753 &_dotls ($self); 1822 &_dotls ($self);
1754 } else { 1823 } else {
1755 $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);
1756 } 1831 }
1757 1832
1758 } elsif (defined $len) { 1833 } elsif (defined $len) {
1759 delete $self->{_rw}; 1834 delete $self->{_rw};
1760 $self->{_eof} = 1; 1835 $self->{_eof} = 1;
… …
1870context in C<< $handle->{tls_ctx} >> after this call and can be used or 1945context in C<< $handle->{tls_ctx} >> after this call and can be used or
1871changed to your liking. Note that the handshake might have already started 1946changed to your liking. Note that the handshake might have already started
1872when this function returns. 1947when this function returns.
1873 1948
1874Due to bugs in OpenSSL, it might or might not be possible to do multiple 1949Due to bugs in OpenSSL, it might or might not be possible to do multiple
1875handshakes on the same stream. Best do not attempt to use the stream after 1950handshakes on the same stream. It is best to not attempt to use the
1876stopping TLS. 1951stream after stopping TLS.
1877 1952
1878This method may invoke callbacks (and therefore the handle might be 1953This method may invoke callbacks (and therefore the handle might be
1879destroyed after it returns). 1954destroyed after it returns).
1880 1955
1881=cut 1956=cut
… …
1935 Net::SSLeay::CTX_set_mode ($tls, 1|2); 2010 Net::SSLeay::CTX_set_mode ($tls, 1|2);
1936 2011
1937 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 2012 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1938 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 2013 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1939 2014
1940 Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf}); 2015 Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
2016 $self->{rbuf} = "";
1941 2017
1942 Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio}); 2018 Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
1943 2019
1944 $self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) } 2020 $self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
1945 if $self->{on_starttls}; 2021 if $self->{on_starttls};
… …
1983 if $self->{tls} > 0; 2059 if $self->{tls} > 0;
1984 2060
1985 delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)}; 2061 delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
1986} 2062}
1987 2063
2064=item $handle->resettls
2065
2066This rarely-used method simply resets and TLS state on the handle, usually
2067causing data loss.
2068
2069One case where it may be useful is when you want to skip over the data in
2070the stream but you are not interested in interpreting it, so data loss is
2071no concern.
2072
2073=cut
2074
2075*resettls = \&_freetls;
2076
1988sub DESTROY { 2077sub DESTROY {
1989 my ($self) = @_; 2078 my ($self) = @_;
1990 2079
1991 &_freetls; 2080 &_freetls;
1992 2081
… …
2001 push @linger, AE::io $fh, 1, sub { 2090 push @linger, AE::io $fh, 1, sub {
2002 my $len = syswrite $fh, $wbuf, length $wbuf; 2091 my $len = syswrite $fh, $wbuf, length $wbuf;
2003 2092
2004 if ($len > 0) { 2093 if ($len > 0) {
2005 substr $wbuf, 0, $len, ""; 2094 substr $wbuf, 0, $len, "";
2006 } else { 2095 } elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
2007 @linger = (); # end 2096 @linger = (); # end
2008 } 2097 }
2009 }; 2098 };
2010 push @linger, AE::timer $linger, 0, sub { 2099 push @linger, AE::timer $linger, 0, sub {
2011 @linger = (); 2100 @linger = ();
… …
2107 2196
2108It is only safe to "forget" the reference inside EOF or error callbacks, 2197It is only safe to "forget" the reference inside EOF or error callbacks,
2109from within all other callbacks, you need to explicitly call the C<< 2198from within all other callbacks, you need to explicitly call the C<<
2110->destroy >> method. 2199->destroy >> method.
2111 2200
2201=item Why is my C<on_eof> callback never called?
2202
2203Probably because your C<on_error> callback is being called instead: When
2204you have outstanding requests in your read queue, then an EOF is
2205considered an error as you clearly expected some data.
2206
2207To avoid this, make sure you have an empty read queue whenever your handle
2208is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
2209an C<on_read> handler that simply pushes the first read requests in the
2210queue.
2211
2212See also the next question, which explains this in a bit more detail.
2213
2214=item How can I serve requests in a loop?
2215
2216Most protocols consist of some setup phase (authentication for example)
2217followed by a request handling phase, where the server waits for requests
2218and handles them, in a loop.
2219
2220There are two important variants: The first (traditional, better) variant
2221handles requests until the server gets some QUIT command, causing it to
2222close the connection first (highly desirable for a busy TCP server). A
2223client dropping the connection is an error, which means this variant can
2224detect an unexpected detection close.
2225
2226To handle this case, always make sure you have a on-empty read queue, by
2227pushing the "read request start" handler on it:
2228
2229 # we assume a request starts with a single line
2230 my @start_request; @start_request = (line => sub {
2231 my ($hdl, $line) = @_;
2232
2233 ... handle request
2234
2235 # push next request read, possibly from a nested callback
2236 $hdl->push_read (@start_request);
2237 });
2238
2239 # auth done, now go into request handling loop
2240 # now push the first @start_request
2241 $hdl->push_read (@start_request);
2242
2243By always having an outstanding C<push_read>, the handle always expects
2244some data and raises the C<EPIPE> error when the connction is dropped
2245unexpectedly.
2246
2247The second variant is a protocol where the client can drop the connection
2248at any time. For TCP, this means that the server machine may run out of
2249sockets easier, and in general, it means you cnanot distinguish a protocl
2250failure/client crash from a normal connection close. Nevertheless, these
2251kinds of protocols are common (and sometimes even the best solution to the
2252problem).
2253
2254Having an outstanding read request at all times is possible if you ignore
2255C<EPIPE> errors, but this doesn't help with when the client drops the
2256connection during a request, which would still be an error.
2257
2258A better solution is to push the initial request read in an C<on_read>
2259callback. This avoids an error, as when the server doesn't expect data
2260(i.e. is idly waiting for the next request, an EOF will not raise an
2261error, but simply result in an C<on_eof> callback. It is also a bit slower
2262and simpler:
2263
2264 # auth done, now go into request handling loop
2265 $hdl->on_read (sub {
2266 my ($hdl) = @_;
2267
2268 # called each time we receive data but the read queue is empty
2269 # simply start read the request
2270
2271 $hdl->push_read (line => sub {
2272 my ($hdl, $line) = @_;
2273
2274 ... handle request
2275
2276 # do nothing special when the request has been handled, just
2277 # let the request queue go empty.
2278 });
2279 });
2280
2112=item I get different callback invocations in TLS mode/Why can't I pause 2281=item I get different callback invocations in TLS mode/Why can't I pause
2113reading? 2282reading?
2114 2283
2115Unlike, say, TCP, TLS connections do not consist of two independent 2284Unlike, say, TCP, TLS connections do not consist of two independent
2116communication channels, one for each direction. Or put differently. The 2285communication channels, one for each direction. Or put differently, the
2117read and write directions are not independent of each other: you cannot 2286read and write directions are not independent of each other: you cannot
2118write data unless you are also prepared to read, and vice versa. 2287write data unless you are also prepared to read, and vice versa.
2119 2288
2120This can mean than, in TLS mode, you might get C<on_error> or C<on_eof> 2289This means that, in TLS mode, you might get C<on_error> or C<on_eof>
2121callback invocations when you are not expecting any read data - the reason 2290callback invocations when you are not expecting any read data - the reason
2122is that AnyEvent::Handle always reads in TLS mode. 2291is that AnyEvent::Handle always reads in TLS mode.
2123 2292
2124During the connection, you have to make sure that you always have a 2293During the connection, you have to make sure that you always have a
2125non-empty read-queue, or an C<on_read> watcher. At the end of the 2294non-empty read-queue, or an C<on_read> watcher. At the end of the
… …
2137 $handle->on_eof (undef); 2306 $handle->on_eof (undef);
2138 $handle->on_error (sub { 2307 $handle->on_error (sub {
2139 my $data = delete $_[0]{rbuf}; 2308 my $data = delete $_[0]{rbuf};
2140 }); 2309 });
2141 2310
2311Note that this example removes the C<rbuf> member from the handle object,
2312which is not normally allowed by the API. It is expressly permitted in
2313this case only, as the handle object needs to be destroyed afterwards.
2314
2142The reason to use C<on_error> is that TCP connections, due to latencies 2315The reason to use C<on_error> is that TCP connections, due to latencies
2143and packets loss, might get closed quite violently with an error, when in 2316and packets loss, might get closed quite violently with an error, when in
2144fact, all data has been received. 2317fact all data has been received.
2145 2318
2146It is usually better to use acknowledgements when transferring data, 2319It is usually better to use acknowledgements when transferring data,
2147to make sure the other side hasn't just died and you got the data 2320to make sure the other side hasn't just died and you got the data
2148intact. This is also one reason why so many internet protocols have an 2321intact. This is also one reason why so many internet protocols have an
2149explicit QUIT command. 2322explicit QUIT command.
… …
2166consider using C<< ->push_shutdown >> instead. 2339consider using C<< ->push_shutdown >> instead.
2167 2340
2168=item I want to contact a TLS/SSL server, I don't care about security. 2341=item I want to contact a TLS/SSL server, I don't care about security.
2169 2342
2170If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS, 2343If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
2171simply connect to it and then create the AnyEvent::Handle with the C<tls> 2344connect to it and then create the AnyEvent::Handle with the C<tls>
2172parameter: 2345parameter:
2173 2346
2174 tcp_connect $host, $port, sub { 2347 tcp_connect $host, $port, sub {
2175 my ($fh) = @_; 2348 my ($fh) = @_;
2176 2349
… …
2276 2449
2277=item * all members not documented here and not prefixed with an underscore 2450=item * all members not documented here and not prefixed with an underscore
2278are free to use in subclasses. 2451are free to use in subclasses.
2279 2452
2280Of course, new versions of AnyEvent::Handle may introduce more "public" 2453Of course, new versions of AnyEvent::Handle may introduce more "public"
2281member variables, but thats just life, at least it is documented. 2454member variables, but that's just life. At least it is documented.
2282 2455
2283=back 2456=back
2284 2457
2285=head1 AUTHOR 2458=head1 AUTHOR
2286 2459

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