ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/AnyEvent/lib/AnyEvent/Handle.pm
(Generate patch)

Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.197 by root, Tue Aug 31 00:59:55 2010 UTC vs.
Revision 1.223 by root, Thu Sep 1 04:07:18 2011 UTC

… …
11 11
12 my $hdl; $hdl = new AnyEvent::Handle 12 my $hdl; $hdl = new AnyEvent::Handle
13 fh => \*STDIN, 13 fh => \*STDIN,
14 on_error => sub { 14 on_error => sub {
15 my ($hdl, $fatal, $msg) = @_; 15 my ($hdl, $fatal, $msg) = @_;
16 warn "got error $msg\n"; 16 AE::log warn => "got error $msg\n";
17 $hdl->destroy; 17 $hdl->destroy;
18 $cv->send; 18 $cv->send;
19 }; 19 };
20 20
21 # send some request line 21 # send some request line
22 $hdl->push_write ("getinfo\015\012"); 22 $hdl->push_write ("getinfo\015\012");
23 23
24 # read the response line 24 # read the response line
25 $hdl->push_read (line => sub { 25 $hdl->push_read (line => sub {
26 my ($hdl, $line) = @_; 26 my ($hdl, $line) = @_;
27 warn "got line <$line>\n"; 27 AE::log warn => "got line <$line>\n";
28 $cv->send; 28 $cv->send;
29 }); 29 });
30 30
31 $cv->recv; 31 $cv->recv;
32 32
33=head1 DESCRIPTION 33=head1 DESCRIPTION
34 34
35This module is a helper module to make it easier to do event-based I/O on 35This is a helper module to make it easier to do event-based I/O on
36stream-based filehandles (sockets, pipes or other stream things). 36stream-based filehandles (sockets, pipes, and other stream things).
37 37
38The L<AnyEvent::Intro> tutorial contains some well-documented 38The L<AnyEvent::Intro> tutorial contains some well-documented
39AnyEvent::Handle examples. 39AnyEvent::Handle examples.
40 40
41In the following, when the documentation refers to of "bytes" then this 41In the following, where the documentation refers to "bytes", it means
42means characters. As sysread and syswrite are used for all I/O, their 42characters. As sysread and syswrite are used for all I/O, their
43treatment of characters applies to this module as well. 43treatment of characters applies to this module as well.
44 44
45At the very minimum, you should specify C<fh> or C<connect>, and the 45At the very minimum, you should specify C<fh> or C<connect>, and the
46C<on_error> callback. 46C<on_error> callback.
47 47
… …
75 } 75 }
76 76
77 \&$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...
… …
112=over 4 114=over 4
113 115
114=item on_prepare => $cb->($handle) 116=item on_prepare => $cb->($handle)
115 117
116This (rarely used) callback is called before a new connection is 118This (rarely used) callback is called before a new connection is
117attempted, but after the file handle has been created. It could be used to 119attempted, but after the file handle has been created (you can access that
120file handle via C<< $handle->{fh} >>). It could be used to prepare the
118prepare the file handle with parameters required for the actual connect 121file handle with parameters required for the actual connect (as opposed to
119(as opposed to settings that can be changed when the connection is already 122settings that can be changed when the connection is already established).
120established).
121 123
122The return value of this callback should be the connect timeout value in 124The return value of this callback should be the connect timeout value in
123seconds (or C<0>, or C<undef>, or the empty list, to indicate the default 125seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
124timeout is to be used). 126default timeout is to be used).
125 127
126=item on_connect => $cb->($handle, $host, $port, $retry->()) 128=item on_connect => $cb->($handle, $host, $port, $retry->())
127 129
128This callback is called when a connection has been successfully established. 130This callback is called when a connection has been successfully established.
129 131
130The actual numeric host and port (the socket peername) are passed as 132The peer's numeric host and port (the socket peername) are passed as
131parameters, together with a retry callback. 133parameters, together with a retry callback.
132 134
133When, for some reason, the handle is not acceptable, then calling 135If, for some reason, the handle is not acceptable, calling C<$retry>
134C<$retry> will continue with the next connection target (in case of 136will continue with the next connection target (in case of multi-homed
135multi-homed hosts or SRV records there can be multiple connection 137hosts or SRV records there can be multiple connection endpoints). At the
136endpoints). At the time it is called the read and write queues, eof 138time it is called the read and write queues, eof status, tls status and
137status, tls status and similar properties of the handle will have been 139similar properties of the handle will have been reset.
138reset.
139 140
140In most cases, ignoring the C<$retry> parameter is the way to go. 141In most cases, you should ignore the C<$retry> parameter.
141 142
142=item on_connect_error => $cb->($handle, $message) 143=item on_connect_error => $cb->($handle, $message)
143 144
144This callback is called when the connection could not be 145This callback is called when the connection could not be
145established. C<$!> will contain the relevant error code, and C<$message> a 146established. C<$!> will contain the relevant error code, and C<$message> a
… …
152 153
153=item on_error => $cb->($handle, $fatal, $message) 154=item on_error => $cb->($handle, $fatal, $message)
154 155
155This is the error callback, which is called when, well, some error 156This is the error callback, which is called when, well, some error
156occured, such as not being able to resolve the hostname, failure to 157occured, such as not being able to resolve the hostname, failure to
157connect or a read error. 158connect, or a read error.
158 159
159Some errors are fatal (which is indicated by C<$fatal> being true). On 160Some errors are fatal (which is indicated by C<$fatal> being true). On
160fatal errors the handle object will be destroyed (by a call to C<< -> 161fatal errors the handle object will be destroyed (by a call to C<< ->
161destroy >>) after invoking the error callback (which means you are free to 162destroy >>) after invoking the error callback (which means you are free to
162examine the handle object). Examples of fatal errors are an EOF condition 163examine the handle object). Examples of fatal errors are an EOF condition
163with active (but unsatisifable) read watchers (C<EPIPE>) or I/O errors. In 164with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
164cases where the other side can close the connection at their will it is 165cases where the other side can close the connection at will, it is
165often easiest to not report C<EPIPE> errors in this callback. 166often easiest to not report C<EPIPE> errors in this callback.
166 167
167AnyEvent::Handle tries to find an appropriate error code for you to check 168AnyEvent::Handle tries to find an appropriate error code for you to check
168against, but in some cases (TLS errors), this does not work well. It is 169against, but in some cases (TLS errors), this does not work well. It is
169recommended to always output the C<$message> argument in human-readable 170recommended to always output the C<$message> argument in human-readable
170error messages (it's usually the same as C<"$!">). 171error messages (it's usually the same as C<"$!">).
171 172
172Non-fatal errors can be retried by simply returning, but it is recommended 173Non-fatal errors can be retried by returning, but it is recommended
173to simply ignore this parameter and instead abondon the handle object 174to simply ignore this parameter and instead abondon the handle object
174when this callback is invoked. Examples of non-fatal errors are timeouts 175when this callback is invoked. Examples of non-fatal errors are timeouts
175C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>). 176C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
176 177
177On callback entrance, the value of C<$!> contains the operating system 178On entry to the callback, the value of C<$!> contains the operating
178error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or 179system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
179C<EPROTO>). 180C<EPROTO>).
180 181
181While not mandatory, it is I<highly> recommended to set this callback, as 182While not mandatory, it is I<highly> recommended to set this callback, as
182you will not be notified of errors otherwise. The default simply calls 183you will not be notified of errors otherwise. The default just calls
183C<croak>. 184C<croak>.
184 185
185=item on_read => $cb->($handle) 186=item on_read => $cb->($handle)
186 187
187This sets the default read callback, which is called when data arrives 188This sets the default read callback, which is called when data arrives
… …
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
… …
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
… …
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
… …
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>
… …
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
… …
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
344try to read during each loop iteration, which affects memory 365to read during each loop iteration. Each handle object will consume
345requirements). Default: C<8192>. 366at least this amount of memory for the read buffer as well, so when
367handling many connections watch out for memory requirements). See also
368C<max_read_size>. Default: C<2048>.
369
370=item max_read_size => <bytes>
371
372The maximum read buffer size used by the dynamic adjustment
373algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
374one go it will double C<read_size> up to the maximum given by this
375option. Default: C<131072> or C<read_size>, whichever is higher.
346 376
347=item low_water_mark => <bytes> 377=item low_water_mark => <bytes>
348 378
349Sets the amount of bytes (default: C<0>) that make up an "empty" write 379Sets 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 380buffer: If the buffer reaches this size or gets even samller it is
351considered empty. 381considered empty.
352 382
353Sometimes it can be beneficial (for performance reasons) to add data to 383Sometimes 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 384the 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 385the operating system kernel usually buffers data as well, so the default
356is good in almost all cases. 386is good in almost all cases.
357 387
358=item linger => <seconds> 388=item linger => <seconds>
359 389
360If non-zero (default: C<3600>), then the destructor of the 390If this is non-zero (default: C<3600>), the destructor of the
361AnyEvent::Handle object will check whether there is still outstanding 391AnyEvent::Handle object will check whether there is still outstanding
362write data and will install a watcher that will write this data to the 392write 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 393socket. No errors will be reported (this mostly matches how the operating
364system treats outstanding data at socket close time). 394system treats outstanding data at socket close time).
365 395
… …
372A string used to identify the remote site - usually the DNS hostname 402A string used to identify the remote site - usually the DNS hostname
373(I<not> IDN!) used to create the connection, rarely the IP address. 403(I<not> IDN!) used to create the connection, rarely the IP address.
374 404
375Apart from being useful in error messages, this string is also used in TLS 405Apart from being useful in error messages, this string is also used in TLS
376peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This 406peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
377verification will be skipped when C<peername> is not specified or 407verification will be skipped when C<peername> is not specified or is
378C<undef>. 408C<undef>.
379 409
380=item tls => "accept" | "connect" | Net::SSLeay::SSL object 410=item tls => "accept" | "connect" | Net::SSLeay::SSL object
381 411
382When this parameter is given, it enables TLS (SSL) mode, that means 412When this parameter is given, it enables TLS (SSL) mode, that means
… …
408B<IMPORTANT:> since Net::SSLeay "objects" are really only integers, 438B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
409passing in the wrong integer will lead to certain crash. This most often 439passing 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 440happens when one uses a stylish C<< tls => 1 >> and is surprised about the
411segmentation fault. 441segmentation fault.
412 442
413See the C<< ->starttls >> method for when need to start TLS negotiation later. 443Use the C<< ->starttls >> method if you need to start TLS negotiation later.
414 444
415=item tls_ctx => $anyevent_tls 445=item tls_ctx => $anyevent_tls
416 446
417Use the given C<AnyEvent::TLS> object to create the new TLS connection 447Use the given C<AnyEvent::TLS> object to create the new TLS connection
418(unless a connection object was specified directly). If this parameter is 448(unless a connection object was specified directly). If this
419missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>. 449parameter is missing (or C<undef>), then AnyEvent::Handle will use
450C<AnyEvent::Handle::TLS_CTX>.
420 451
421Instead of an object, you can also specify a hash reference with C<< key 452Instead 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 453=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
423new TLS context object. 454new TLS context object.
424 455
… …
433 464
434TLS handshake failures will not cause C<on_error> to be invoked when this 465TLS 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>. 466callback is in effect, instead, the error message will be passed to C<on_starttls>.
436 467
437Without this callback, handshake failures lead to C<on_error> being 468Without this callback, handshake failures lead to C<on_error> being
438called, as normal. 469called as usual.
439 470
440Note that you cannot call C<starttls> right again in this callback. If you 471Note 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 472need to do that, start an zero-second timer instead whose callback can
442then call C<< ->starttls >> again. 473then call C<< ->starttls >> again.
443 474
444=item on_stoptls => $cb->($handle) 475=item on_stoptls => $cb->($handle)
445 476
… …
493 $self->{connect}[0], 524 $self->{connect}[0],
494 $self->{connect}[1], 525 $self->{connect}[1],
495 sub { 526 sub {
496 my ($fh, $host, $port, $retry) = @_; 527 my ($fh, $host, $port, $retry) = @_;
497 528
529 delete $self->{_connect}; # no longer needed
530
498 if ($fh) { 531 if ($fh) {
499 $self->{fh} = $fh; 532 $self->{fh} = $fh;
500 533
501 delete $self->{_skip_drain_rbuf}; 534 delete $self->{_skip_drain_rbuf};
502 $self->_start; 535 $self->_start;
… …
509 }); 542 });
510 543
511 } else { 544 } else {
512 if ($self->{on_connect_error}) { 545 if ($self->{on_connect_error}) {
513 $self->{on_connect_error}($self, "$!"); 546 $self->{on_connect_error}($self, "$!");
514 $self->destroy; 547 $self->destroy if $self;
515 } else { 548 } else {
516 $self->_error ($!, 1); 549 $self->_error ($!, 1);
517 } 550 }
518 } 551 }
519 }, 552 },
520 sub { 553 sub {
521 local $self->{fh} = $_[0]; 554 local $self->{fh} = $_[0];
522 555
523 $self->{on_prepare} 556 $self->{on_prepare}
524 ? $self->{on_prepare}->($self) 557 ? $self->{on_prepare}->($self)
525 : () 558 : ()
526 } 559 }
527 ); 560 );
528 } 561 }
529 562
… …
547 580
548 $self->{_activity} = 581 $self->{_activity} =
549 $self->{_ractivity} = 582 $self->{_ractivity} =
550 $self->{_wactivity} = AE::now; 583 $self->{_wactivity} = AE::now;
551 584
585 $self->{read_size} ||= 2048;
586 $self->{max_read_size} = $self->{read_size}
587 if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
588
552 $self->timeout (delete $self->{timeout} ) if $self->{timeout}; 589 $self->timeout (delete $self->{timeout} ) if $self->{timeout};
553 $self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout}; 590 $self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
554 $self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout}; 591 $self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
555 592
556 $self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay}; 593 $self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
… …
559 $self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1); 596 $self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
560 597
561 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx}) 598 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
562 if $self->{tls}; 599 if $self->{tls};
563 600
564 $self->on_drain (delete $self->{on_drain}) if $self->{on_drain}; 601 $self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
565 602
566 $self->start_read 603 $self->start_read
567 if $self->{on_read} || @{ $self->{_queue} }; 604 if $self->{on_read} || @{ $self->{_queue} };
568 605
569 $self->_drain_wbuf; 606 $self->_drain_wbuf;
… …
645=cut 682=cut
646 683
647sub no_delay { 684sub no_delay {
648 $_[0]{no_delay} = $_[1]; 685 $_[0]{no_delay} = $_[1];
649 686
650 eval {
651 local $SIG{__DIE__};
652 setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1] 687 setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
653 if $_[0]{fh}; 688 if $_[0]{fh};
654 };
655} 689}
656 690
657=item $handle->keepalive ($boolean) 691=item $handle->keepalive ($boolean)
658 692
659Enables or disables the C<keepalive> setting (see constructor argument of 693Enables or disables the C<keepalive> setting (see constructor argument of
… …
727 761
728=item $handle->rbuf_max ($max_octets) 762=item $handle->rbuf_max ($max_octets)
729 763
730Configures the C<rbuf_max> setting (C<undef> disables it). 764Configures the C<rbuf_max> setting (C<undef> disables it).
731 765
766=item $handle->wbuf_max ($max_octets)
767
768Configures the C<wbuf_max> setting (C<undef> disables it).
769
732=cut 770=cut
733 771
734sub rbuf_max { 772sub rbuf_max {
735 $_[0]{rbuf_max} = $_[1]; 773 $_[0]{rbuf_max} = $_[1];
736} 774}
737 775
776sub wbuf_max {
777 $_[0]{wbuf_max} = $_[1];
778}
779
738############################################################################# 780#############################################################################
739 781
740=item $handle->timeout ($seconds) 782=item $handle->timeout ($seconds)
741 783
742=item $handle->rtimeout ($seconds) 784=item $handle->rtimeout ($seconds)
743 785
744=item $handle->wtimeout ($seconds) 786=item $handle->wtimeout ($seconds)
745 787
746Configures (or disables) the inactivity timeout. 788Configures (or disables) the inactivity timeout.
789
790The timeout will be checked instantly, so this method might destroy the
791handle before it returns.
747 792
748=item $handle->timeout_reset 793=item $handle->timeout_reset
749 794
750=item $handle->rtimeout_reset 795=item $handle->rtimeout_reset
751 796
… …
768 $_[0]{$on_timeout} = $_[1]; 813 $_[0]{$on_timeout} = $_[1];
769 }; 814 };
770 815
771 *$timeout = sub { 816 *$timeout = sub {
772 my ($self, $new_value) = @_; 817 my ($self, $new_value) = @_;
818
819 $new_value >= 0
820 or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
773 821
774 $self->{$timeout} = $new_value; 822 $self->{$timeout} = $new_value;
775 delete $self->{$tw}; &$cb; 823 delete $self->{$tw}; &$cb;
776 }; 824 };
777 825
… …
857 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf}); 905 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
858} 906}
859 907
860=item $handle->push_write ($data) 908=item $handle->push_write ($data)
861 909
862Queues the given scalar to be written. You can push as much data as you 910Queues the given scalar to be written. You can push as much data as
863want (only limited by the available memory), as C<AnyEvent::Handle> 911you want (only limited by the available memory and C<wbuf_max>), as
864buffers it independently of the kernel. 912C<AnyEvent::Handle> buffers it independently of the kernel.
865 913
866This method may invoke callbacks (and therefore the handle might be 914This method may invoke callbacks (and therefore the handle might be
867destroyed after it returns). 915destroyed after it returns).
868 916
869=cut 917=cut
… …
897 $cb->() unless $self->{autocork}; 945 $cb->() unless $self->{autocork};
898 946
899 # if still data left in wbuf, we need to poll 947 # if still data left in wbuf, we need to poll
900 $self->{_ww} = AE::io $self->{fh}, 1, $cb 948 $self->{_ww} = AE::io $self->{fh}, 1, $cb
901 if length $self->{wbuf}; 949 if length $self->{wbuf};
950
951 if (
952 defined $self->{wbuf_max}
953 && $self->{wbuf_max} < length $self->{wbuf}
954 ) {
955 $self->_error (Errno::ENOSPC, 1), return;
956 }
902 }; 957 };
903} 958}
904 959
905our %WH; 960our %WH;
906 961
… …
1041before it was actually written. One way to do that is to replace your 1096before 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 1097C<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 1098C<low_water_mark> to C<0>). This method is a shorthand for just that, and
1044replaces the C<on_drain> callback with: 1099replaces the C<on_drain> callback with:
1045 1100
1046 sub { shutdown $_[0]{fh}, 1 } # for push_shutdown 1101 sub { shutdown $_[0]{fh}, 1 }
1047 1102
1048This simply shuts down the write side and signals an EOF condition to the 1103This simply shuts down the write side and signals an EOF condition to the
1049the peer. 1104the peer.
1050 1105
1051You can rely on the normal read queue and C<on_eof> handling 1106You can rely on the normal read queue and C<on_eof> handling
… …
1073 1128
1074Whenever the given C<type> is used, C<push_write> will the function with 1129Whenever the given C<type> is used, C<push_write> will the function with
1075the handle object and the remaining arguments. 1130the handle object and the remaining arguments.
1076 1131
1077The function is supposed to return a single octet string that will be 1132The function is supposed to return a single octet string that will be
1078appended to the write buffer, so you cna mentally treat this function as a 1133appended to the write buffer, so you can mentally treat this function as a
1079"arguments to on-the-wire-format" converter. 1134"arguments to on-the-wire-format" converter.
1080 1135
1081Example: implement a custom write type C<join> that joins the remaining 1136Example: implement a custom write type C<join> that joins the remaining
1082arguments using the first one. 1137arguments using the first one.
1083 1138
… …
1117partial message has been received so far), or change the read queue with 1172partial message has been received so far), or change the read queue with
1118e.g. C<push_read>. 1173e.g. C<push_read>.
1119 1174
1120In the more complex case, you want to queue multiple callbacks. In this 1175In the more complex case, you want to queue multiple callbacks. In this
1121case, AnyEvent::Handle will call the first queued callback each time new 1176case, 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 1177data arrives (also the first time it is queued) and remove it when it has
1123done its job (see C<push_read>, below). 1178done its job (see C<push_read>, below).
1124 1179
1125This way you can, for example, push three line-reads, followed by reading 1180This way you can, for example, push three line-reads, followed by reading
1126a chunk of data, and AnyEvent::Handle will execute them in order. 1181a chunk of data, and AnyEvent::Handle will execute them in order.
1127 1182
… …
1272 $self->_drain_rbuf if $cb; 1327 $self->_drain_rbuf if $cb;
1273} 1328}
1274 1329
1275=item $handle->rbuf 1330=item $handle->rbuf
1276 1331
1277Returns the read buffer (as a modifiable lvalue). 1332Returns the read buffer (as a modifiable lvalue). You can also access the
1333read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
1334much faster, and no less clean).
1278 1335
1279You can access the read buffer directly as the C<< ->{rbuf} >> 1336The only operation allowed on the read buffer (apart from looking at it)
1280member, if you want. However, the only operation allowed on the 1337is removing data from its beginning. Otherwise modifying or appending to
1281read buffer (apart from looking at it) is removing data from its 1338it 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 1339
1285NOTE: The read buffer should only be used or modified if the C<on_read>, 1340NOTE: 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 1341callback or when C<push_read> or C<unshift_read> are used with a single
1287automatically manage the read buffer. 1342callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
1343will manage the read buffer on their own.
1288 1344
1289=cut 1345=cut
1290 1346
1291sub rbuf : lvalue { 1347sub rbuf : lvalue {
1292 $_[0]{rbuf} 1348 $_[0]{rbuf}
… …
1343 my $cb = pop; 1399 my $cb = pop;
1344 1400
1345 if (@_) { 1401 if (@_) {
1346 my $type = shift; 1402 my $type = shift;
1347 1403
1404 $cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
1348 $cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read") 1405 or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
1349 ->($self, $cb, @_); 1406 ->($self, $cb, @_);
1350 } 1407 }
1351 1408
1352 unshift @{ $self->{_queue} }, $cb; 1409 unshift @{ $self->{_queue} }, $cb;
1353 $self->_drain_rbuf; 1410 $self->_drain_rbuf;
… …
1375data. 1432data.
1376 1433
1377Example: read 2 bytes. 1434Example: read 2 bytes.
1378 1435
1379 $handle->push_read (chunk => 2, sub { 1436 $handle->push_read (chunk => 2, sub {
1380 warn "yay ", unpack "H*", $_[1]; 1437 AE::log debug => "yay " . unpack "H*", $_[1];
1381 }); 1438 });
1382 1439
1383=cut 1440=cut
1384 1441
1385register_read_type chunk => sub { 1442register_read_type chunk => sub {
… …
1461the receive buffer when neither C<$accept> nor C<$reject> match, 1518the receive buffer when neither C<$accept> nor C<$reject> match,
1462and everything preceding and including the match will be accepted 1519and everything preceding and including the match will be accepted
1463unconditionally. This is useful to skip large amounts of data that you 1520unconditionally. This is useful to skip large amounts of data that you
1464know cannot be matched, so that the C<$accept> or C<$reject> regex do not 1521know cannot be matched, so that the C<$accept> or C<$reject> regex do not
1465have to start matching from the beginning. This is purely an optimisation 1522have to start matching from the beginning. This is purely an optimisation
1466and is usually worth only when you expect more than a few kilobytes. 1523and is usually worth it only when you expect more than a few kilobytes.
1467 1524
1468Example: expect a http header, which ends at C<\015\012\015\012>. Since we 1525Example: 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 1526expect 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 1527a 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 1528it only accepts something not ending in either \015 or \012, as these are
1472required for the accept regex. 1529required for the accept regex.
1473 1530
1474 $handle->push_read (regex => 1531 $handle->push_read (regex =>
… …
1487 1544
1488 sub { 1545 sub {
1489 # accept 1546 # accept
1490 if ($$rbuf =~ $accept) { 1547 if ($$rbuf =~ $accept) {
1491 $data .= substr $$rbuf, 0, $+[0], ""; 1548 $data .= substr $$rbuf, 0, $+[0], "";
1492 $cb->($self, $data); 1549 $cb->($_[0], $data);
1493 return 1; 1550 return 1;
1494 } 1551 }
1495 1552
1496 # reject 1553 # reject
1497 if ($reject && $$rbuf =~ $reject) { 1554 if ($reject && $$rbuf =~ $reject) {
1498 $self->_error (Errno::EBADMSG); 1555 $_[0]->_error (Errno::EBADMSG);
1499 } 1556 }
1500 1557
1501 # skip 1558 # skip
1502 if ($skip && $$rbuf =~ $skip) { 1559 if ($skip && $$rbuf =~ $skip) {
1503 $data .= substr $$rbuf, 0, $+[0], ""; 1560 $data .= substr $$rbuf, 0, $+[0], "";
… …
1519 my ($self, $cb) = @_; 1576 my ($self, $cb) = @_;
1520 1577
1521 sub { 1578 sub {
1522 unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) { 1579 unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
1523 if ($_[0]{rbuf} =~ /[^0-9]/) { 1580 if ($_[0]{rbuf} =~ /[^0-9]/) {
1524 $self->_error (Errno::EBADMSG); 1581 $_[0]->_error (Errno::EBADMSG);
1525 } 1582 }
1526 return; 1583 return;
1527 } 1584 }
1528 1585
1529 my $len = $1; 1586 my $len = $1;
1530 1587
1531 $self->unshift_read (chunk => $len, sub { 1588 $_[0]->unshift_read (chunk => $len, sub {
1532 my $string = $_[1]; 1589 my $string = $_[1];
1533 $_[0]->unshift_read (chunk => 1, sub { 1590 $_[0]->unshift_read (chunk => 1, sub {
1534 if ($_[1] eq ",") { 1591 if ($_[1] eq ",") {
1535 $cb->($_[0], $string); 1592 $cb->($_[0], $string);
1536 } else { 1593 } else {
1537 $self->_error (Errno::EBADMSG); 1594 $_[0]->_error (Errno::EBADMSG);
1538 } 1595 }
1539 }); 1596 });
1540 }); 1597 });
1541 1598
1542 1 1599 1
… …
1615 1672
1616 my $data; 1673 my $data;
1617 my $rbuf = \$self->{rbuf}; 1674 my $rbuf = \$self->{rbuf};
1618 1675
1619 sub { 1676 sub {
1620 my $ref = eval { $json->incr_parse ($self->{rbuf}) }; 1677 my $ref = eval { $json->incr_parse ($_[0]{rbuf}) };
1621 1678
1622 if ($ref) { 1679 if ($ref) {
1623 $self->{rbuf} = $json->incr_text; 1680 $_[0]{rbuf} = $json->incr_text;
1624 $json->incr_text = ""; 1681 $json->incr_text = "";
1625 $cb->($self, $ref); 1682 $cb->($_[0], $ref);
1626 1683
1627 1 1684 1
1628 } elsif ($@) { 1685 } elsif ($@) {
1629 # error case 1686 # error case
1630 $json->incr_skip; 1687 $json->incr_skip;
1631 1688
1632 $self->{rbuf} = $json->incr_text; 1689 $_[0]{rbuf} = $json->incr_text;
1633 $json->incr_text = ""; 1690 $json->incr_text = "";
1634 1691
1635 $self->_error (Errno::EBADMSG); 1692 $_[0]->_error (Errno::EBADMSG);
1636 1693
1637 () 1694 ()
1638 } else { 1695 } else {
1639 $self->{rbuf} = ""; 1696 $_[0]{rbuf} = "";
1640 1697
1641 () 1698 ()
1642 } 1699 }
1643 } 1700 }
1644}; 1701};
… …
1677 # read remaining chunk 1734 # read remaining chunk
1678 $_[0]->unshift_read (chunk => $len, sub { 1735 $_[0]->unshift_read (chunk => $len, sub {
1679 if (my $ref = eval { Storable::thaw ($_[1]) }) { 1736 if (my $ref = eval { Storable::thaw ($_[1]) }) {
1680 $cb->($_[0], $ref); 1737 $cb->($_[0], $ref);
1681 } else { 1738 } else {
1682 $self->_error (Errno::EBADMSG); 1739 $_[0]->_error (Errno::EBADMSG);
1683 } 1740 }
1684 }); 1741 });
1685 } 1742 }
1686 1743
1687 1 1744 1
… …
1725Note that AnyEvent::Handle will automatically C<start_read> for you when 1782Note that AnyEvent::Handle will automatically C<start_read> for you when
1726you change the C<on_read> callback or push/unshift a read callback, and it 1783you change the C<on_read> callback or push/unshift a read callback, and it
1727will automatically C<stop_read> for you when neither C<on_read> is set nor 1784will automatically C<stop_read> for you when neither C<on_read> is set nor
1728there are any read requests in the queue. 1785there are any read requests in the queue.
1729 1786
1730These methods will have no effect when in TLS mode (as TLS doesn't support 1787In older versions of this module (<= 5.3), these methods had no effect,
1731half-duplex connections). 1788as TLS does not support half-duplex connections. In current versions they
1789work as expected, as this behaviour is required to avoid certain resource
1790attacks, where the program would be forced to read (and buffer) arbitrary
1791amounts of data before being able to send some data. The drawback is that
1792some readings of the the SSL/TLS specifications basically require this
1793attack to be working, as SSL/TLS implementations might stall sending data
1794during a rehandshake.
1795
1796As a guideline, during the initial handshake, you should not stop reading,
1797and as a client, it might cause problems, depending on your applciation.
1732 1798
1733=cut 1799=cut
1734 1800
1735sub stop_read { 1801sub stop_read {
1736 my ($self) = @_; 1802 my ($self) = @_;
1737 1803
1738 delete $self->{_rw} unless $self->{tls}; 1804 delete $self->{_rw};
1739} 1805}
1740 1806
1741sub start_read { 1807sub start_read {
1742 my ($self) = @_; 1808 my ($self) = @_;
1743 1809
1744 unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) { 1810 unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
1745 Scalar::Util::weaken $self; 1811 Scalar::Util::weaken $self;
1746 1812
1747 $self->{_rw} = AE::io $self->{fh}, 0, sub { 1813 $self->{_rw} = AE::io $self->{fh}, 0, sub {
1748 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf}); 1814 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1749 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf; 1815 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
1750 1816
1751 if ($len > 0) { 1817 if ($len > 0) {
1752 $self->{_activity} = $self->{_ractivity} = AE::now; 1818 $self->{_activity} = $self->{_ractivity} = AE::now;
1753 1819
1754 if ($self->{tls}) { 1820 if ($self->{tls}) {
1755 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf); 1821 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1756 1822
1757 &_dotls ($self); 1823 &_dotls ($self);
1758 } else { 1824 } else {
1759 $self->_drain_rbuf; 1825 $self->_drain_rbuf;
1826 }
1827
1828 if ($len == $self->{read_size}) {
1829 $self->{read_size} *= 2;
1830 $self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
1831 if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
1760 } 1832 }
1761 1833
1762 } elsif (defined $len) { 1834 } elsif (defined $len) {
1763 delete $self->{_rw}; 1835 delete $self->{_rw};
1764 $self->{_eof} = 1; 1836 $self->{_eof} = 1;
… …
1874context in C<< $handle->{tls_ctx} >> after this call and can be used or 1946context in C<< $handle->{tls_ctx} >> after this call and can be used or
1875changed to your liking. Note that the handshake might have already started 1947changed to your liking. Note that the handshake might have already started
1876when this function returns. 1948when this function returns.
1877 1949
1878Due to bugs in OpenSSL, it might or might not be possible to do multiple 1950Due to bugs in OpenSSL, it might or might not be possible to do multiple
1879handshakes on the same stream. Best do not attempt to use the stream after 1951handshakes on the same stream. It is best to not attempt to use the
1880stopping TLS. 1952stream after stopping TLS.
1881 1953
1882This method may invoke callbacks (and therefore the handle might be 1954This method may invoke callbacks (and therefore the handle might be
1883destroyed after it returns). 1955destroyed after it returns).
1884 1956
1885=cut 1957=cut
… …
1939 Net::SSLeay::CTX_set_mode ($tls, 1|2); 2011 Net::SSLeay::CTX_set_mode ($tls, 1|2);
1940 2012
1941 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 2013 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1942 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 2014 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1943 2015
1944 Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf}); 2016 Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
2017 $self->{rbuf} = "";
1945 2018
1946 Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio}); 2019 Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
1947 2020
1948 $self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) } 2021 $self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
1949 if $self->{on_starttls}; 2022 if $self->{on_starttls};
… …
1987 if $self->{tls} > 0; 2060 if $self->{tls} > 0;
1988 2061
1989 delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)}; 2062 delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
1990} 2063}
1991 2064
2065=item $handle->resettls
2066
2067This rarely-used method simply resets and TLS state on the handle, usually
2068causing data loss.
2069
2070One case where it may be useful is when you want to skip over the data in
2071the stream but you are not interested in interpreting it, so data loss is
2072no concern.
2073
2074=cut
2075
2076*resettls = \&_freetls;
2077
1992sub DESTROY { 2078sub DESTROY {
1993 my ($self) = @_; 2079 my ($self) = @_;
1994 2080
1995 &_freetls; 2081 &_freetls;
1996 2082
… …
2005 push @linger, AE::io $fh, 1, sub { 2091 push @linger, AE::io $fh, 1, sub {
2006 my $len = syswrite $fh, $wbuf, length $wbuf; 2092 my $len = syswrite $fh, $wbuf, length $wbuf;
2007 2093
2008 if ($len > 0) { 2094 if ($len > 0) {
2009 substr $wbuf, 0, $len, ""; 2095 substr $wbuf, 0, $len, "";
2010 } else { 2096 } elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
2011 @linger = (); # end 2097 @linger = (); # end
2012 } 2098 }
2013 }; 2099 };
2014 push @linger, AE::timer $linger, 0, sub { 2100 push @linger, AE::timer $linger, 0, sub {
2015 @linger = (); 2101 @linger = ();
… …
2111 2197
2112It is only safe to "forget" the reference inside EOF or error callbacks, 2198It is only safe to "forget" the reference inside EOF or error callbacks,
2113from within all other callbacks, you need to explicitly call the C<< 2199from within all other callbacks, you need to explicitly call the C<<
2114->destroy >> method. 2200->destroy >> method.
2115 2201
2202=item Why is my C<on_eof> callback never called?
2203
2204Probably because your C<on_error> callback is being called instead: When
2205you have outstanding requests in your read queue, then an EOF is
2206considered an error as you clearly expected some data.
2207
2208To avoid this, make sure you have an empty read queue whenever your handle
2209is supposed to be "idle" (i.e. connection closes are O.K.). You can set
2210an C<on_read> handler that simply pushes the first read requests in the
2211queue.
2212
2213See also the next question, which explains this in a bit more detail.
2214
2215=item How can I serve requests in a loop?
2216
2217Most protocols consist of some setup phase (authentication for example)
2218followed by a request handling phase, where the server waits for requests
2219and handles them, in a loop.
2220
2221There are two important variants: The first (traditional, better) variant
2222handles requests until the server gets some QUIT command, causing it to
2223close the connection first (highly desirable for a busy TCP server). A
2224client dropping the connection is an error, which means this variant can
2225detect an unexpected detection close.
2226
2227To handle this case, always make sure you have a on-empty read queue, by
2228pushing the "read request start" handler on it:
2229
2230 # we assume a request starts with a single line
2231 my @start_request; @start_request = (line => sub {
2232 my ($hdl, $line) = @_;
2233
2234 ... handle request
2235
2236 # push next request read, possibly from a nested callback
2237 $hdl->push_read (@start_request);
2238 });
2239
2240 # auth done, now go into request handling loop
2241 # now push the first @start_request
2242 $hdl->push_read (@start_request);
2243
2244By always having an outstanding C<push_read>, the handle always expects
2245some data and raises the C<EPIPE> error when the connction is dropped
2246unexpectedly.
2247
2248The second variant is a protocol where the client can drop the connection
2249at any time. For TCP, this means that the server machine may run out of
2250sockets easier, and in general, it means you cannot distinguish a protocl
2251failure/client crash from a normal connection close. Nevertheless, these
2252kinds of protocols are common (and sometimes even the best solution to the
2253problem).
2254
2255Having an outstanding read request at all times is possible if you ignore
2256C<EPIPE> errors, but this doesn't help with when the client drops the
2257connection during a request, which would still be an error.
2258
2259A better solution is to push the initial request read in an C<on_read>
2260callback. This avoids an error, as when the server doesn't expect data
2261(i.e. is idly waiting for the next request, an EOF will not raise an
2262error, but simply result in an C<on_eof> callback. It is also a bit slower
2263and simpler:
2264
2265 # auth done, now go into request handling loop
2266 $hdl->on_read (sub {
2267 my ($hdl) = @_;
2268
2269 # called each time we receive data but the read queue is empty
2270 # simply start read the request
2271
2272 $hdl->push_read (line => sub {
2273 my ($hdl, $line) = @_;
2274
2275 ... handle request
2276
2277 # do nothing special when the request has been handled, just
2278 # let the request queue go empty.
2279 });
2280 });
2281
2116=item I get different callback invocations in TLS mode/Why can't I pause 2282=item I get different callback invocations in TLS mode/Why can't I pause
2117reading? 2283reading?
2118 2284
2119Unlike, say, TCP, TLS connections do not consist of two independent 2285Unlike, say, TCP, TLS connections do not consist of two independent
2120communication channels, one for each direction. Or put differently. The 2286communication channels, one for each direction. Or put differently, the
2121read and write directions are not independent of each other: you cannot 2287read and write directions are not independent of each other: you cannot
2122write data unless you are also prepared to read, and vice versa. 2288write data unless you are also prepared to read, and vice versa.
2123 2289
2124This can mean than, in TLS mode, you might get C<on_error> or C<on_eof> 2290This 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 2291callback invocations when you are not expecting any read data - the reason
2126is that AnyEvent::Handle always reads in TLS mode. 2292is that AnyEvent::Handle always reads in TLS mode.
2127 2293
2128During the connection, you have to make sure that you always have a 2294During 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 2295non-empty read-queue, or an C<on_read> watcher. At the end of the
… …
2141 $handle->on_eof (undef); 2307 $handle->on_eof (undef);
2142 $handle->on_error (sub { 2308 $handle->on_error (sub {
2143 my $data = delete $_[0]{rbuf}; 2309 my $data = delete $_[0]{rbuf};
2144 }); 2310 });
2145 2311
2312Note that this example removes the C<rbuf> member from the handle object,
2313which is not normally allowed by the API. It is expressly permitted in
2314this case only, as the handle object needs to be destroyed afterwards.
2315
2146The reason to use C<on_error> is that TCP connections, due to latencies 2316The 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 2317and packets loss, might get closed quite violently with an error, when in
2148fact, all data has been received. 2318fact all data has been received.
2149 2319
2150It is usually better to use acknowledgements when transferring data, 2320It is usually better to use acknowledgements when transferring data,
2151to make sure the other side hasn't just died and you got the data 2321to 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 2322intact. This is also one reason why so many internet protocols have an
2153explicit QUIT command. 2323explicit QUIT command.
… …
2160C<low_water_mark> this will be called precisely when all data has been 2330C<low_water_mark> this will be called precisely when all data has been
2161written to the socket: 2331written to the socket:
2162 2332
2163 $handle->push_write (...); 2333 $handle->push_write (...);
2164 $handle->on_drain (sub { 2334 $handle->on_drain (sub {
2165 warn "all data submitted to the kernel\n"; 2335 AE::log debug => "all data submitted to the kernel\n";
2166 undef $handle; 2336 undef $handle;
2167 }); 2337 });
2168 2338
2169If you just want to queue some data and then signal EOF to the other side, 2339If you just want to queue some data and then signal EOF to the other side,
2170consider using C<< ->push_shutdown >> instead. 2340consider using C<< ->push_shutdown >> instead.
2171 2341
2172=item I want to contact a TLS/SSL server, I don't care about security. 2342=item I want to contact a TLS/SSL server, I don't care about security.
2173 2343
2174If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS, 2344If 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> 2345connect to it and then create the AnyEvent::Handle with the C<tls>
2176parameter: 2346parameter:
2177 2347
2178 tcp_connect $host, $port, sub { 2348 tcp_connect $host, $port, sub {
2179 my ($fh) = @_; 2349 my ($fh) = @_;
2180 2350
… …
2280 2450
2281=item * all members not documented here and not prefixed with an underscore 2451=item * all members not documented here and not prefixed with an underscore
2282are free to use in subclasses. 2452are free to use in subclasses.
2283 2453
2284Of course, new versions of AnyEvent::Handle may introduce more "public" 2454Of course, new versions of AnyEvent::Handle may introduce more "public"
2285member variables, but thats just life, at least it is documented. 2455member variables, but that's just life. At least it is documented.
2286 2456
2287=back 2457=back
2288 2458
2289=head1 AUTHOR 2459=head1 AUTHOR
2290 2460

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines