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Revision 1.52 by root, Mon Jun 2 09:10:38 2008 UTC vs.
Revision 1.219 by root, Mon Jul 18 01:19:43 2011 UTC

1package AnyEvent::Handle;
2
3no warnings;
4use strict;
5
6use AnyEvent ();
7use AnyEvent::Util qw(WSAEWOULDBLOCK);
8use Scalar::Util ();
9use Carp ();
10use Fcntl ();
11use Errno qw(EAGAIN EINTR);
12
13=head1 NAME 1=head1 NAME
14 2
15AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent 3AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
16
17=cut
18
19our $VERSION = 4.1;
20 4
21=head1 SYNOPSIS 5=head1 SYNOPSIS
22 6
23 use AnyEvent; 7 use AnyEvent;
24 use AnyEvent::Handle; 8 use AnyEvent::Handle;
25 9
26 my $cv = AnyEvent->condvar; 10 my $cv = AnyEvent->condvar;
27 11
28 my $handle = 12 my $hdl; $hdl = new AnyEvent::Handle
29 AnyEvent::Handle->new (
30 fh => \*STDIN, 13 fh => \*STDIN,
31 on_eof => sub { 14 on_error => sub {
32 $cv->broadcast; 15 my ($hdl, $fatal, $msg) = @_;
33 }, 16 warn "got error $msg\n";
17 $hdl->destroy;
18 $cv->send;
34 ); 19 };
35 20
36 # send some request line 21 # send some request line
37 $handle->push_write ("getinfo\015\012"); 22 $hdl->push_write ("getinfo\015\012");
38 23
39 # read the response line 24 # read the response line
40 $handle->push_read (line => sub { 25 $hdl->push_read (line => sub {
41 my ($handle, $line) = @_; 26 my ($hdl, $line) = @_;
42 warn "read line <$line>\n"; 27 warn "got line <$line>\n";
43 $cv->send; 28 $cv->send;
44 }); 29 });
45 30
46 $cv->recv; 31 $cv->recv;
47 32
48=head1 DESCRIPTION 33=head1 DESCRIPTION
49 34
50This 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
51filehandles. For utility functions for doing non-blocking connects and accepts 36stream-based filehandles (sockets, pipes, and other stream things).
52on sockets see L<AnyEvent::Util>.
53 37
38The L<AnyEvent::Intro> tutorial contains some well-documented
39AnyEvent::Handle examples.
40
54In the following, when the documentation refers to of "bytes" then this 41In the following, where the documentation refers to "bytes", it means
55means characters. As sysread and syswrite are used for all I/O, their 42characters. As sysread and syswrite are used for all I/O, their
56treatment of characters applies to this module as well. 43treatment of characters applies to this module as well.
44
45At the very minimum, you should specify C<fh> or C<connect>, and the
46C<on_error> callback.
57 47
58All callbacks will be invoked with the handle object as their first 48All callbacks will be invoked with the handle object as their first
59argument. 49argument.
60 50
51=cut
52
53package AnyEvent::Handle;
54
55use Scalar::Util ();
56use List::Util ();
57use Carp ();
58use Errno qw(EAGAIN EINTR);
59
60use AnyEvent (); BEGIN { AnyEvent::common_sense }
61use AnyEvent::Util qw(WSAEWOULDBLOCK);
62
63our $VERSION = $AnyEvent::VERSION;
64
65sub _load_func($) {
66 my $func = $_[0];
67
68 unless (defined &$func) {
69 my $pkg = $func;
70 do {
71 $pkg =~ s/::[^:]+$//
72 or return;
73 eval "require $pkg";
74 } until defined &$func;
75 }
76
77 \&$func
78}
79
80sub MAX_READ_SIZE() { 131072 }
81
61=head1 METHODS 82=head1 METHODS
62 83
63=over 4 84=over 4
64 85
65=item B<new (%args)> 86=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
66 87
67The constructor supports these arguments (all as key => value pairs). 88The constructor supports these arguments (all as C<< key => value >> pairs).
68 89
69=over 4 90=over 4
70 91
71=item fh => $filehandle [MANDATORY] 92=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
72 93
73The filehandle this L<AnyEvent::Handle> object will operate on. 94The filehandle this L<AnyEvent::Handle> object will operate on.
74
75NOTE: The filehandle will be set to non-blocking (using 95NOTE: The filehandle will be set to non-blocking mode (using
76AnyEvent::Util::fh_nonblocking). 96C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
97that mode.
77 98
99=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
100
101Try to connect to the specified host and service (port), using
102C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
103default C<peername>.
104
105You have to specify either this parameter, or C<fh>, above.
106
107It is possible to push requests on the read and write queues, and modify
108properties of the stream, even while AnyEvent::Handle is connecting.
109
110When this parameter is specified, then the C<on_prepare>,
111C<on_connect_error> and C<on_connect> callbacks will be called under the
112appropriate circumstances:
113
114=over 4
115
78=item on_eof => $cb->($handle) 116=item on_prepare => $cb->($handle)
79 117
80Set the callback to be called when an end-of-file condition is detcted, 118This (rarely used) callback is called before a new connection is
81i.e. in the case of a socket, when the other side has closed the 119attempted, but after the file handle has been created (you can access that
82connection cleanly. 120file handle via C<< $handle->{fh} >>). It could be used to prepare the
121file handle with parameters required for the actual connect (as opposed to
122settings that can be changed when the connection is already established).
83 123
84While not mandatory, it is highly recommended to set an eof callback, 124The return value of this callback should be the connect timeout value in
85otherwise you might end up with a closed socket while you are still 125seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
86waiting for data. 126default timeout is to be used).
87 127
128=item on_connect => $cb->($handle, $host, $port, $retry->())
129
130This callback is called when a connection has been successfully established.
131
132The peer's numeric host and port (the socket peername) are passed as
133parameters, together with a retry callback.
134
135If, for some reason, the handle is not acceptable, calling C<$retry>
136will continue with the next connection target (in case of multi-homed
137hosts or SRV records there can be multiple connection endpoints). At the
138time it is called the read and write queues, eof status, tls status and
139similar properties of the handle will have been reset.
140
141In most cases, you should ignore the C<$retry> parameter.
142
143=item on_connect_error => $cb->($handle, $message)
144
145This callback is called when the connection could not be
146established. C<$!> will contain the relevant error code, and C<$message> a
147message describing it (usually the same as C<"$!">).
148
149If this callback isn't specified, then C<on_error> will be called with a
150fatal error instead.
151
152=back
153
88=item on_error => $cb->($handle, $fatal) 154=item on_error => $cb->($handle, $fatal, $message)
89 155
90This is the error callback, which is called when, well, some error 156This is the error callback, which is called when, well, some error
91occured, such as not being able to resolve the hostname, failure to 157occured, such as not being able to resolve the hostname, failure to
92connect or a read error. 158connect, or a read error.
93 159
94Some errors are fatal (which is indicated by C<$fatal> being true). On 160Some errors are fatal (which is indicated by C<$fatal> being true). On
95fatal errors the handle object will be shut down and will not be 161fatal errors the handle object will be destroyed (by a call to C<< ->
162destroy >>) after invoking the error callback (which means you are free to
163examine the handle object). Examples of fatal errors are an EOF condition
164with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
165cases where the other side can close the connection at will, it is
166often easiest to not report C<EPIPE> errors in this callback.
167
168AnyEvent::Handle tries to find an appropriate error code for you to check
169against, but in some cases (TLS errors), this does not work well. It is
170recommended to always output the C<$message> argument in human-readable
171error messages (it's usually the same as C<"$!">).
172
96usable. Non-fatal errors can be retried by simply returning, but it is 173Non-fatal errors can be retried by returning, but it is recommended
97recommended to simply ignore this parameter and instead abondon the handle 174to simply ignore this parameter and instead abondon the handle object
98object when this callback is invoked. 175when this callback is invoked. Examples of non-fatal errors are timeouts
176C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
99 177
100On callback entrance, the value of C<$!> contains the operating system 178On entry to the callback, the value of C<$!> contains the operating
101error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>). 179system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
180C<EPROTO>).
102 181
103While 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
104you will not be notified of errors otherwise. The default simply calls 183you will not be notified of errors otherwise. The default just calls
105C<croak>. 184C<croak>.
106 185
107=item on_read => $cb->($handle) 186=item on_read => $cb->($handle)
108 187
109This sets the default read callback, which is called when data arrives 188This sets the default read callback, which is called when data arrives
110and no read request is in the queue. 189and no read request is in the queue (unlike read queue callbacks, this
190callback will only be called when at least one octet of data is in the
191read buffer).
111 192
112To 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 >>
113method or access the C<$handle->{rbuf}> member directly. 194method or access the C<< $handle->{rbuf} >> member directly. Note that you
195must not enlarge or modify the read buffer, you can only remove data at
196the beginning from it.
114 197
198You can also call C<< ->push_read (...) >> or any other function that
199modifies the read queue. Or do both. Or ...
200
115When an EOF condition is detected then AnyEvent::Handle will first try to 201When an EOF condition is detected, AnyEvent::Handle will first try to
116feed all the remaining data to the queued callbacks and C<on_read> before 202feed all the remaining data to the queued callbacks and C<on_read> before
117calling the C<on_eof> callback. If no progress can be made, then a fatal 203calling the C<on_eof> callback. If no progress can be made, then a fatal
118error will be raised (with C<$!> set to C<EPIPE>). 204error will be raised (with C<$!> set to C<EPIPE>).
119 205
206Note that, unlike requests in the read queue, an C<on_read> callback
207doesn't mean you I<require> some data: if there is an EOF and there
208are outstanding read requests then an error will be flagged. With an
209C<on_read> callback, the C<on_eof> callback will be invoked.
210
211=item on_eof => $cb->($handle)
212
213Set the callback to be called when an end-of-file condition is detected,
214i.e. in the case of a socket, when the other side has closed the
215connection cleanly, and there are no outstanding read requests in the
216queue (if there are read requests, then an EOF counts as an unexpected
217connection close and will be flagged as an error).
218
219For sockets, this just means that the other side has stopped sending data,
220you can still try to write data, and, in fact, one can return from the EOF
221callback and continue writing data, as only the read part has been shut
222down.
223
224If an EOF condition has been detected but no C<on_eof> callback has been
225set, then a fatal error will be raised with C<$!> set to <0>.
226
120=item on_drain => $cb->($handle) 227=item on_drain => $cb->($handle)
121 228
122This 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
123(or when the callback is set and the buffer is empty already). 230(or immediately if the buffer is empty already).
124 231
125To append to the write buffer, use the C<< ->push_write >> method. 232To append to the write buffer, use the C<< ->push_write >> method.
126 233
234This callback is useful when you don't want to put all of your write data
235into the queue at once, for example, when you want to write the contents
236of some file to the socket you might not want to read the whole file into
237memory and push it into the queue, but instead only read more data from
238the file when the write queue becomes empty.
239
127=item timeout => $fractional_seconds 240=item timeout => $fractional_seconds
128 241
242=item rtimeout => $fractional_seconds
243
244=item wtimeout => $fractional_seconds
245
129If non-zero, then this enables an "inactivity" timeout: whenever this many 246If non-zero, then these enables an "inactivity" timeout: whenever this
130seconds pass without a successful read or write on the underlying file 247many seconds pass without a successful read or write on the underlying
131handle, the C<on_timeout> callback will be invoked (and if that one is 248file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
132missing, an C<ETIMEDOUT> error will be raised). 249will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
250error will be raised).
133 251
252There are three variants of the timeouts that work independently of each
253other, for both read and write (triggered when nothing was read I<OR>
254written), just read (triggered when nothing was read), and just write:
255C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
256C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
257C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
258
134Note 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
135any outstanding read or write requests: If you plan to keep the connection 260outstanding read or write requests: If you plan to keep the connection
136idle then you should disable the timout temporarily or ignore the timeout 261idle then you should disable the timeout temporarily or ignore the
137in the C<on_timeout> callback. 262timeout in the corresponding C<on_timeout> callback, in which case
263AnyEvent::Handle will simply restart the timeout.
138 264
139Zero (the default) disables this timeout. 265Zero (the default) disables the corresponding timeout.
140 266
141=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)
142 272
143Called whenever the inactivity timeout passes. If you return from this 273Called whenever the inactivity timeout passes. If you return from this
144callback, 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,
145so this condition is not fatal in any way. 275so this condition is not fatal in any way.
146 276
147=item rbuf_max => <bytes> 277=item rbuf_max => <bytes>
148 278
149If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>) 279If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
150when the read buffer ever (strictly) exceeds this size. This is useful to 280when the read buffer ever (strictly) exceeds this size. This is useful to
151avoid denial-of-service attacks. 281avoid some forms of denial-of-service attacks.
152 282
153For example, a server accepting connections from untrusted sources should 283For example, a server accepting connections from untrusted sources should
154be 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
155(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
156amount 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
157isn't finished). 287isn't finished).
158 288
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
304=item autocork => <boolean>
305
306When disabled (the default), C<push_write> will try to immediately
307write the data to the handle if possible. This avoids having to register
308a write watcher and wait for the next event loop iteration, but can
309be inefficient if you write multiple small chunks (on the wire, this
310disadvantage is usually avoided by your kernel's nagle algorithm, see
311C<no_delay>, but this option can save costly syscalls).
312
313When enabled, writes will always be queued till the next event loop
314iteration. This is efficient when you do many small writes per iteration,
315but less efficient when you do a single write only per iteration (or when
316the write buffer often is full). It also increases write latency.
317
318=item no_delay => <boolean>
319
320When doing small writes on sockets, your operating system kernel might
321wait a bit for more data before actually sending it out. This is called
322the Nagle algorithm, and usually it is beneficial.
323
324In some situations you want as low a delay as possible, which can be
325accomplishd by setting this option to a true value.
326
327The default is your operating system's default behaviour (most likely
328enabled). This option explicitly enables or disables it, if possible.
329
330=item keepalive => <boolean>
331
332Enables (default disable) the SO_KEEPALIVE option on the stream socket:
333normally, TCP connections have no time-out once established, so TCP
334connections, once established, can stay alive forever even when the other
335side has long gone. TCP keepalives are a cheap way to take down long-lived
336TCP connections when the other side becomes unreachable. While the default
337is OS-dependent, TCP keepalives usually kick in after around two hours,
338and, if the other side doesn't reply, take down the TCP connection some 10
339to 15 minutes later.
340
341It is harmless to specify this option for file handles that do not support
342keepalives, and enabling it on connections that are potentially long-lived
343is usually a good idea.
344
345=item oobinline => <boolean>
346
347BSD majorly fucked up the implementation of TCP urgent data. The result
348is that almost no OS implements TCP according to the specs, and every OS
349implements it slightly differently.
350
351If you want to handle TCP urgent data, then setting this flag (the default
352is enabled) gives you the most portable way of getting urgent data, by
353putting it into the stream.
354
355Since BSD emulation of OOB data on top of TCP's urgent data can have
356security implications, AnyEvent::Handle sets this flag automatically
357unless explicitly specified. Note that setting this flag after
358establishing a connection I<may> be a bit too late (data loss could
359already have occured on BSD systems), but at least it will protect you
360from most attacks.
361
159=item read_size => <bytes> 362=item read_size => <bytes>
160 363
161The default read block size (the amount of bytes this module will try to read 364The initial read block size, the number of bytes this module will try to
162during each (loop iteration). Default: C<8192>. 365read during each loop iteration. Each handle object will consume at least
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.
163 375
164=item low_water_mark => <bytes> 376=item low_water_mark => <bytes>
165 377
166Sets 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
167buffer: 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
168considered empty. 380considered empty.
169 381
382Sometimes it can be beneficial (for performance reasons) to add data to
383the write buffer before it is fully drained, but this is a rare case, as
384the operating system kernel usually buffers data as well, so the default
385is good in almost all cases.
386
387=item linger => <seconds>
388
389If this is non-zero (default: C<3600>), the destructor of the
390AnyEvent::Handle object will check whether there is still outstanding
391write data and will install a watcher that will write this data to the
392socket. No errors will be reported (this mostly matches how the operating
393system treats outstanding data at socket close time).
394
395This will not work for partial TLS data that could not be encoded
396yet. This data will be lost. Calling the C<stoptls> method in time might
397help.
398
399=item peername => $string
400
401A string used to identify the remote site - usually the DNS hostname
402(I<not> IDN!) used to create the connection, rarely the IP address.
403
404Apart from being useful in error messages, this string is also used in TLS
405peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
406verification will be skipped when C<peername> is not specified or is
407C<undef>.
408
170=item tls => "accept" | "connect" | Net::SSLeay::SSL object 409=item tls => "accept" | "connect" | Net::SSLeay::SSL object
171 410
172When this parameter is given, it enables TLS (SSL) mode, that means it 411When this parameter is given, it enables TLS (SSL) mode, that means
173will start making tls handshake and will transparently encrypt/decrypt 412AnyEvent will start a TLS handshake as soon as the connection has been
174data. 413established and will transparently encrypt/decrypt data afterwards.
414
415All TLS protocol errors will be signalled as C<EPROTO>, with an
416appropriate error message.
175 417
176TLS mode requires Net::SSLeay to be installed (it will be loaded 418TLS mode requires Net::SSLeay to be installed (it will be loaded
177automatically when you try to create a TLS handle). 419automatically when you try to create a TLS handle): this module doesn't
420have a dependency on that module, so if your module requires it, you have
421to add the dependency yourself.
178 422
179For the TLS server side, use C<accept>, and for the TLS client side of a 423Unlike TCP, TLS has a server and client side: for the TLS server side, use
180connection, use C<connect> mode. 424C<accept>, and for the TLS client side of a connection, use C<connect>
425mode.
181 426
182You can also provide your own TLS connection object, but you have 427You can also provide your own TLS connection object, but you have
183to make sure that you call either C<Net::SSLeay::set_connect_state> 428to make sure that you call either C<Net::SSLeay::set_connect_state>
184or C<Net::SSLeay::set_accept_state> on it before you pass it to 429or C<Net::SSLeay::set_accept_state> on it before you pass it to
185AnyEvent::Handle. 430AnyEvent::Handle. Also, this module will take ownership of this connection
431object.
186 432
433At some future point, AnyEvent::Handle might switch to another TLS
434implementation, then the option to use your own session object will go
435away.
436
437B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
438passing in the wrong integer will lead to certain crash. This most often
439happens when one uses a stylish C<< tls => 1 >> and is surprised about the
440segmentation fault.
441
187See the C<starttls> method if you need to start TLs negotiation later. 442Use the C<< ->starttls >> method if you need to start TLS negotiation later.
188 443
189=item tls_ctx => $ssl_ctx 444=item tls_ctx => $anyevent_tls
190 445
191Use the given Net::SSLeay::CTX object to create the new TLS connection 446Use the given C<AnyEvent::TLS> object to create the new TLS connection
192(unless a connection object was specified directly). If this parameter is 447(unless a connection object was specified directly). If this
193missing, 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>.
450
451Instead of an object, you can also specify a hash reference with C<< key
452=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
453new TLS context object.
454
455=item on_starttls => $cb->($handle, $success[, $error_message])
456
457This callback will be invoked when the TLS/SSL handshake has finished. If
458C<$success> is true, then the TLS handshake succeeded, otherwise it failed
459(C<on_stoptls> will not be called in this case).
460
461The session in C<< $handle->{tls} >> can still be examined in this
462callback, even when the handshake was not successful.
463
464TLS handshake failures will not cause C<on_error> to be invoked when this
465callback is in effect, instead, the error message will be passed to C<on_starttls>.
466
467Without this callback, handshake failures lead to C<on_error> being
468called as usual.
469
470Note that you cannot just call C<starttls> again in this callback. If you
471need to do that, start an zero-second timer instead whose callback can
472then call C<< ->starttls >> again.
473
474=item on_stoptls => $cb->($handle)
475
476When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
477set, then it will be invoked after freeing the TLS session. If it is not,
478then a TLS shutdown condition will be treated like a normal EOF condition
479on the handle.
480
481The session in C<< $handle->{tls} >> can still be examined in this
482callback.
483
484This callback will only be called on TLS shutdowns, not when the
485underlying handle signals EOF.
194 486
195=item json => JSON or JSON::XS object 487=item json => JSON or JSON::XS object
196 488
197This is the json coder object used by the C<json> read and write types. 489This is the json coder object used by the C<json> read and write types.
198 490
199If you don't supply it, then AnyEvent::Handle will create and use a 491If you don't supply it, then AnyEvent::Handle will create and use a
200suitable one, which will write and expect UTF-8 encoded JSON texts. 492suitable one (on demand), which will write and expect UTF-8 encoded JSON
493texts.
201 494
202Note that you are responsible to depend on the JSON module if you want to 495Note that you are responsible to depend on the JSON module if you want to
203use this functionality, as AnyEvent does not have a dependency itself. 496use this functionality, as AnyEvent does not have a dependency itself.
204 497
205=item filter_r => $cb
206
207=item filter_w => $cb
208
209These exist, but are undocumented at this time.
210
211=back 498=back
212 499
213=cut 500=cut
214 501
215sub new { 502sub new {
216 my $class = shift; 503 my $class = shift;
217
218 my $self = bless { @_ }, $class; 504 my $self = bless { @_ }, $class;
219 505
220 $self->{fh} or Carp::croak "mandatory argument fh is missing"; 506 if ($self->{fh}) {
507 $self->_start;
508 return unless $self->{fh}; # could be gone by now
509
510 } elsif ($self->{connect}) {
511 require AnyEvent::Socket;
512
513 $self->{peername} = $self->{connect}[0]
514 unless exists $self->{peername};
515
516 $self->{_skip_drain_rbuf} = 1;
517
518 {
519 Scalar::Util::weaken (my $self = $self);
520
521 $self->{_connect} =
522 AnyEvent::Socket::tcp_connect (
523 $self->{connect}[0],
524 $self->{connect}[1],
525 sub {
526 my ($fh, $host, $port, $retry) = @_;
527
528 delete $self->{_connect}; # no longer needed
529
530 if ($fh) {
531 $self->{fh} = $fh;
532
533 delete $self->{_skip_drain_rbuf};
534 $self->_start;
535
536 $self->{on_connect}
537 and $self->{on_connect}($self, $host, $port, sub {
538 delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
539 $self->{_skip_drain_rbuf} = 1;
540 &$retry;
541 });
542
543 } else {
544 if ($self->{on_connect_error}) {
545 $self->{on_connect_error}($self, "$!");
546 $self->destroy if $self;
547 } else {
548 $self->_error ($!, 1);
549 }
550 }
551 },
552 sub {
553 local $self->{fh} = $_[0];
554
555 $self->{on_prepare}
556 ? $self->{on_prepare}->($self)
557 : ()
558 }
559 );
560 }
561
562 } else {
563 Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
564 }
565
566 $self
567}
568
569sub _start {
570 my ($self) = @_;
571
572 # too many clueless people try to use udp and similar sockets
573 # with AnyEvent::Handle, do them a favour.
574 my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
575 Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
576 if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
221 577
222 AnyEvent::Util::fh_nonblocking $self->{fh}, 1; 578 AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
223 579
224 if ($self->{tls}) { 580 $self->{_activity} =
225 require Net::SSLeay; 581 $self->{_ractivity} =
582 $self->{_wactivity} = AE::now;
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
588 $self->timeout (delete $self->{timeout} ) if $self->{timeout};
589 $self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
590 $self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
591
592 $self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
593 $self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
594
595 $self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
596
226 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx}); 597 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
227 } 598 if $self->{tls};
228 599
229# $self->on_eof (delete $self->{on_eof} ) if $self->{on_eof}; # nop
230# $self->on_error (delete $self->{on_error}) if $self->{on_error}; # nop
231# $self->on_read (delete $self->{on_read} ) if $self->{on_read}; # nop
232 $self->on_drain (delete $self->{on_drain}) if $self->{on_drain}; 600 $self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
233 601
234 $self->{_activity} = AnyEvent->now;
235 $self->_timeout;
236
237 $self->start_read; 602 $self->start_read
603 if $self->{on_read} || @{ $self->{_queue} };
238 604
239 $self 605 $self->_drain_wbuf;
240}
241
242sub _shutdown {
243 my ($self) = @_;
244
245 delete $self->{_tw};
246 delete $self->{_rw};
247 delete $self->{_ww};
248 delete $self->{fh};
249
250 $self->stoptls;
251} 606}
252 607
253sub _error { 608sub _error {
254 my ($self, $errno, $fatal) = @_; 609 my ($self, $errno, $fatal, $message) = @_;
255
256 $self->_shutdown
257 if $fatal;
258 610
259 $! = $errno; 611 $! = $errno;
612 $message ||= "$!";
260 613
261 if ($self->{on_error}) { 614 if ($self->{on_error}) {
262 $self->{on_error}($self, $fatal); 615 $self->{on_error}($self, $fatal, $message);
263 } else { 616 $self->destroy if $fatal;
617 } elsif ($self->{fh} || $self->{connect}) {
618 $self->destroy;
264 Carp::croak "AnyEvent::Handle uncaught error: $!"; 619 Carp::croak "AnyEvent::Handle uncaught error: $message";
265 } 620 }
266} 621}
267 622
268=item $fh = $handle->fh 623=item $fh = $handle->fh
269 624
270This method returns the file handle of the L<AnyEvent::Handle> object. 625This method returns the file handle used to create the L<AnyEvent::Handle> object.
271 626
272=cut 627=cut
273 628
274sub fh { $_[0]{fh} } 629sub fh { $_[0]{fh} }
275 630
293 $_[0]{on_eof} = $_[1]; 648 $_[0]{on_eof} = $_[1];
294} 649}
295 650
296=item $handle->on_timeout ($cb) 651=item $handle->on_timeout ($cb)
297 652
298Replace the current C<on_timeout> callback, or disables the callback 653=item $handle->on_rtimeout ($cb)
299(but not the timeout) if C<$cb> = C<undef>. See C<timeout> constructor
300argument.
301 654
302=cut 655=item $handle->on_wtimeout ($cb)
303 656
657Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
658callback, or disables the callback (but not the timeout) if C<$cb> =
659C<undef>. See the C<timeout> constructor argument and method.
660
661=cut
662
663# see below
664
665=item $handle->autocork ($boolean)
666
667Enables or disables the current autocork behaviour (see C<autocork>
668constructor argument). Changes will only take effect on the next write.
669
670=cut
671
672sub autocork {
673 $_[0]{autocork} = $_[1];
674}
675
676=item $handle->no_delay ($boolean)
677
678Enables or disables the C<no_delay> setting (see constructor argument of
679the same name for details).
680
681=cut
682
683sub no_delay {
684 $_[0]{no_delay} = $_[1];
685
686 setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
687 if $_[0]{fh};
688}
689
690=item $handle->keepalive ($boolean)
691
692Enables or disables the C<keepalive> setting (see constructor argument of
693the same name for details).
694
695=cut
696
697sub keepalive {
698 $_[0]{keepalive} = $_[1];
699
700 eval {
701 local $SIG{__DIE__};
702 setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
703 if $_[0]{fh};
704 };
705}
706
707=item $handle->oobinline ($boolean)
708
709Enables or disables the C<oobinline> setting (see constructor argument of
710the same name for details).
711
712=cut
713
714sub oobinline {
715 $_[0]{oobinline} = $_[1];
716
717 eval {
718 local $SIG{__DIE__};
719 setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
720 if $_[0]{fh};
721 };
722}
723
724=item $handle->keepalive ($boolean)
725
726Enables or disables the C<keepalive> setting (see constructor argument of
727the same name for details).
728
729=cut
730
731sub keepalive {
732 $_[0]{keepalive} = $_[1];
733
734 eval {
735 local $SIG{__DIE__};
736 setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
737 if $_[0]{fh};
738 };
739}
740
741=item $handle->on_starttls ($cb)
742
743Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
744
745=cut
746
747sub on_starttls {
748 $_[0]{on_starttls} = $_[1];
749}
750
751=item $handle->on_stoptls ($cb)
752
753Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
754
755=cut
756
304sub on_timeout { 757sub on_stoptls {
305 $_[0]{on_timeout} = $_[1]; 758 $_[0]{on_stoptls} = $_[1];
759}
760
761=item $handle->rbuf_max ($max_octets)
762
763Configures the C<rbuf_max> setting (C<undef> disables it).
764
765=item $handle->wbuf_max ($max_octets)
766
767Configures the C<wbuf_max> setting (C<undef> disables it).
768
769=cut
770
771sub rbuf_max {
772 $_[0]{rbuf_max} = $_[1];
773}
774
775sub wbuf_max {
776 $_[0]{wbuf_max} = $_[1];
306} 777}
307 778
308############################################################################# 779#############################################################################
309 780
310=item $handle->timeout ($seconds) 781=item $handle->timeout ($seconds)
311 782
783=item $handle->rtimeout ($seconds)
784
785=item $handle->wtimeout ($seconds)
786
312Configures (or disables) the inactivity timeout. 787Configures (or disables) the inactivity timeout.
313 788
314=cut 789The timeout will be checked instantly, so this method might destroy the
790handle before it returns.
315 791
316sub timeout { 792=item $handle->timeout_reset
793
794=item $handle->rtimeout_reset
795
796=item $handle->wtimeout_reset
797
798Reset the activity timeout, as if data was received or sent.
799
800These methods are cheap to call.
801
802=cut
803
804for my $dir ("", "r", "w") {
805 my $timeout = "${dir}timeout";
806 my $tw = "_${dir}tw";
807 my $on_timeout = "on_${dir}timeout";
808 my $activity = "_${dir}activity";
809 my $cb;
810
811 *$on_timeout = sub {
812 $_[0]{$on_timeout} = $_[1];
813 };
814
815 *$timeout = sub {
317 my ($self, $timeout) = @_; 816 my ($self, $new_value) = @_;
318 817
818 $new_value >= 0
819 or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
820
319 $self->{timeout} = $timeout; 821 $self->{$timeout} = $new_value;
320 $self->_timeout; 822 delete $self->{$tw}; &$cb;
321} 823 };
322 824
825 *{"${dir}timeout_reset"} = sub {
826 $_[0]{$activity} = AE::now;
827 };
828
829 # main workhorse:
323# reset the timeout watcher, as neccessary 830 # reset the timeout watcher, as neccessary
324# also check for time-outs 831 # also check for time-outs
325sub _timeout { 832 $cb = sub {
326 my ($self) = @_; 833 my ($self) = @_;
327 834
328 if ($self->{timeout}) { 835 if ($self->{$timeout} && $self->{fh}) {
329 my $NOW = AnyEvent->now; 836 my $NOW = AE::now;
330 837
331 # when would the timeout trigger? 838 # when would the timeout trigger?
332 my $after = $self->{_activity} + $self->{timeout} - $NOW; 839 my $after = $self->{$activity} + $self->{$timeout} - $NOW;
333 840
334 # now or in the past already? 841 # now or in the past already?
335 if ($after <= 0) { 842 if ($after <= 0) {
336 $self->{_activity} = $NOW; 843 $self->{$activity} = $NOW;
337 844
338 if ($self->{on_timeout}) { 845 if ($self->{$on_timeout}) {
339 $self->{on_timeout}($self); 846 $self->{$on_timeout}($self);
340 } else { 847 } else {
341 $self->_error (&Errno::ETIMEDOUT); 848 $self->_error (Errno::ETIMEDOUT);
849 }
850
851 # callback could have changed timeout value, optimise
852 return unless $self->{$timeout};
853
854 # calculate new after
855 $after = $self->{$timeout};
342 } 856 }
343 857
344 # callbakx could have changed timeout value, optimise 858 Scalar::Util::weaken $self;
345 return unless $self->{timeout}; 859 return unless $self; # ->error could have destroyed $self
346 860
347 # calculate new after 861 $self->{$tw} ||= AE::timer $after, 0, sub {
348 $after = $self->{timeout}; 862 delete $self->{$tw};
863 $cb->($self);
864 };
865 } else {
866 delete $self->{$tw};
349 } 867 }
350
351 Scalar::Util::weaken $self;
352
353 $self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
354 delete $self->{_tw};
355 $self->_timeout;
356 });
357 } else {
358 delete $self->{_tw};
359 } 868 }
360} 869}
361 870
362############################################################################# 871#############################################################################
363 872
379=item $handle->on_drain ($cb) 888=item $handle->on_drain ($cb)
380 889
381Sets the C<on_drain> callback or clears it (see the description of 890Sets the C<on_drain> callback or clears it (see the description of
382C<on_drain> in the constructor). 891C<on_drain> in the constructor).
383 892
893This method may invoke callbacks (and therefore the handle might be
894destroyed after it returns).
895
384=cut 896=cut
385 897
386sub on_drain { 898sub on_drain {
387 my ($self, $cb) = @_; 899 my ($self, $cb) = @_;
388 900
389 $self->{on_drain} = $cb; 901 $self->{on_drain} = $cb;
390 902
391 $cb->($self) 903 $cb->($self)
392 if $cb && $self->{low_water_mark} >= length $self->{wbuf}; 904 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
393} 905}
394 906
395=item $handle->push_write ($data) 907=item $handle->push_write ($data)
396 908
397Queues 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
398want (only limited by the available memory), as C<AnyEvent::Handle> 910you want (only limited by the available memory and C<wbuf_max>), as
399buffers it independently of the kernel. 911C<AnyEvent::Handle> buffers it independently of the kernel.
912
913This method may invoke callbacks (and therefore the handle might be
914destroyed after it returns).
400 915
401=cut 916=cut
402 917
403sub _drain_wbuf { 918sub _drain_wbuf {
404 my ($self) = @_; 919 my ($self) = @_;
408 Scalar::Util::weaken $self; 923 Scalar::Util::weaken $self;
409 924
410 my $cb = sub { 925 my $cb = sub {
411 my $len = syswrite $self->{fh}, $self->{wbuf}; 926 my $len = syswrite $self->{fh}, $self->{wbuf};
412 927
413 if ($len >= 0) { 928 if (defined $len) {
414 substr $self->{wbuf}, 0, $len, ""; 929 substr $self->{wbuf}, 0, $len, "";
415 930
416 $self->{_activity} = AnyEvent->now; 931 $self->{_activity} = $self->{_wactivity} = AE::now;
417 932
418 $self->{on_drain}($self) 933 $self->{on_drain}($self)
419 if $self->{low_water_mark} >= length $self->{wbuf} 934 if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
420 && $self->{on_drain}; 935 && $self->{on_drain};
421 936
422 delete $self->{_ww} unless length $self->{wbuf}; 937 delete $self->{_ww} unless length $self->{wbuf};
423 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) { 938 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
424 $self->_error ($!, 1); 939 $self->_error ($!, 1);
425 } 940 }
426 }; 941 };
427 942
428 # try to write data immediately 943 # try to write data immediately
429 $cb->(); 944 $cb->() unless $self->{autocork};
430 945
431 # if still data left in wbuf, we need to poll 946 # if still data left in wbuf, we need to poll
432 $self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb) 947 $self->{_ww} = AE::io $self->{fh}, 1, $cb
433 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 }
434 }; 956 };
435} 957}
436 958
437our %WH; 959our %WH;
438 960
961# deprecated
439sub register_write_type($$) { 962sub register_write_type($$) {
440 $WH{$_[0]} = $_[1]; 963 $WH{$_[0]} = $_[1];
441} 964}
442 965
443sub push_write { 966sub push_write {
444 my $self = shift; 967 my $self = shift;
445 968
446 if (@_ > 1) { 969 if (@_ > 1) {
447 my $type = shift; 970 my $type = shift;
448 971
972 @_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
449 @_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write") 973 or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
450 ->($self, @_); 974 ->($self, @_);
451 } 975 }
452 976
977 # we downgrade here to avoid hard-to-track-down bugs,
978 # and diagnose the problem earlier and better.
979
453 if ($self->{filter_w}) { 980 if ($self->{tls}) {
454 $self->{filter_w}($self, \$_[0]); 981 utf8::downgrade $self->{_tls_wbuf} .= $_[0];
982 &_dotls ($self) if $self->{fh};
455 } else { 983 } else {
456 $self->{wbuf} .= $_[0]; 984 utf8::downgrade $self->{wbuf} .= $_[0];
457 $self->_drain_wbuf; 985 $self->_drain_wbuf if $self->{fh};
458 } 986 }
459} 987}
460 988
461=item $handle->push_write (type => @args) 989=item $handle->push_write (type => @args)
462 990
463Instead of formatting your data yourself, you can also let this module do 991Instead of formatting your data yourself, you can also let this module
464the job by specifying a type and type-specific arguments. 992do the job by specifying a type and type-specific arguments. You
993can also specify the (fully qualified) name of a package, in which
994case AnyEvent tries to load the package and then expects to find the
995C<anyevent_write_type> function inside (see "custom write types", below).
465 996
466Predefined types are (if you have ideas for additional types, feel free to 997Predefined types are (if you have ideas for additional types, feel free to
467drop by and tell us): 998drop by and tell us):
468 999
469=over 4 1000=over 4
476=cut 1007=cut
477 1008
478register_write_type netstring => sub { 1009register_write_type netstring => sub {
479 my ($self, $string) = @_; 1010 my ($self, $string) = @_;
480 1011
481 sprintf "%d:%s,", (length $string), $string 1012 (length $string) . ":$string,"
1013};
1014
1015=item packstring => $format, $data
1016
1017An octet string prefixed with an encoded length. The encoding C<$format>
1018uses the same format as a Perl C<pack> format, but must specify a single
1019integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
1020optional C<!>, C<< < >> or C<< > >> modifier).
1021
1022=cut
1023
1024register_write_type packstring => sub {
1025 my ($self, $format, $string) = @_;
1026
1027 pack "$format/a*", $string
482}; 1028};
483 1029
484=item json => $array_or_hashref 1030=item json => $array_or_hashref
485 1031
486Encodes the given hash or array reference into a JSON object. Unless you 1032Encodes the given hash or array reference into a JSON object. Unless you
511Other languages could read single lines terminated by a newline and pass 1057Other languages could read single lines terminated by a newline and pass
512this line into their JSON decoder of choice. 1058this line into their JSON decoder of choice.
513 1059
514=cut 1060=cut
515 1061
1062sub json_coder() {
1063 eval { require JSON::XS; JSON::XS->new->utf8 }
1064 || do { require JSON; JSON->new->utf8 }
1065}
1066
516register_write_type json => sub { 1067register_write_type json => sub {
517 my ($self, $ref) = @_; 1068 my ($self, $ref) = @_;
518 1069
519 require JSON; 1070 my $json = $self->{json} ||= json_coder;
520 1071
521 $self->{json} ? $self->{json}->encode ($ref) 1072 $json->encode ($ref)
522 : JSON::encode_json ($ref)
523}; 1073};
524 1074
525=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args) 1075=item storable => $reference
526 1076
527This function (not method) lets you add your own types to C<push_write>. 1077Freezes the given reference using L<Storable> and writes it to the
528Whenever the given C<type> is used, C<push_write> will invoke the code 1078handle. Uses the C<nfreeze> format.
529reference with the handle object and the remaining arguments.
530 1079
531The code reference is supposed to return a single octet string that will 1080=cut
532be appended to the write buffer.
533 1081
534Note that this is a function, and all types registered this way will be 1082register_write_type storable => sub {
535global, so try to use unique names. 1083 my ($self, $ref) = @_;
1084
1085 require Storable;
1086
1087 pack "w/a*", Storable::nfreeze ($ref)
1088};
536 1089
537=back 1090=back
1091
1092=item $handle->push_shutdown
1093
1094Sometimes you know you want to close the socket after writing your data
1095before it was actually written. One way to do that is to replace your
1096C<on_drain> handler by a callback that shuts down the socket (and set
1097C<low_water_mark> to C<0>). This method is a shorthand for just that, and
1098replaces the C<on_drain> callback with:
1099
1100 sub { shutdown $_[0]{fh}, 1 }
1101
1102This simply shuts down the write side and signals an EOF condition to the
1103the peer.
1104
1105You can rely on the normal read queue and C<on_eof> handling
1106afterwards. This is the cleanest way to close a connection.
1107
1108This method may invoke callbacks (and therefore the handle might be
1109destroyed after it returns).
1110
1111=cut
1112
1113sub push_shutdown {
1114 my ($self) = @_;
1115
1116 delete $self->{low_water_mark};
1117 $self->on_drain (sub { shutdown $_[0]{fh}, 1 });
1118}
1119
1120=item custom write types - Package::anyevent_write_type $handle, @args
1121
1122Instead of one of the predefined types, you can also specify the name of
1123a package. AnyEvent will try to load the package and then expects to find
1124a function named C<anyevent_write_type> inside. If it isn't found, it
1125progressively tries to load the parent package until it either finds the
1126function (good) or runs out of packages (bad).
1127
1128Whenever the given C<type> is used, C<push_write> will the function with
1129the handle object and the remaining arguments.
1130
1131The function is supposed to return a single octet string that will be
1132appended to the write buffer, so you cna mentally treat this function as a
1133"arguments to on-the-wire-format" converter.
1134
1135Example: implement a custom write type C<join> that joins the remaining
1136arguments using the first one.
1137
1138 $handle->push_write (My::Type => " ", 1,2,3);
1139
1140 # uses the following package, which can be defined in the "My::Type" or in
1141 # the "My" modules to be auto-loaded, or just about anywhere when the
1142 # My::Type::anyevent_write_type is defined before invoking it.
1143
1144 package My::Type;
1145
1146 sub anyevent_write_type {
1147 my ($handle, $delim, @args) = @_;
1148
1149 join $delim, @args
1150 }
538 1151
539=cut 1152=cut
540 1153
541############################################################################# 1154#############################################################################
542 1155
551ways, 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
552a queue. 1165a queue.
553 1166
554In 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
555new 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
556enough is there) from the read buffer (C<< $handle->rbuf >>) if you want 1169enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
557or not. 1170leave the data there if you want to accumulate more (e.g. when only a
1171partial message has been received so far), or change the read queue with
1172e.g. C<push_read>.
558 1173
559In 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
560case, AnyEvent::Handle will call the first queued callback each time new 1175case, AnyEvent::Handle will call the first queued callback each time new
561data arrives and removes it when it has done its job (see C<push_read>, 1176data arrives (also the first time it is queued) and remove it when it has
562below). 1177done its job (see C<push_read>, below).
563 1178
564This 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
565a chunk of data, and AnyEvent::Handle will execute them in order. 1180a chunk of data, and AnyEvent::Handle will execute them in order.
566 1181
567Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by 1182Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
580 # handle xml 1195 # handle xml
581 }); 1196 });
582 }); 1197 });
583 }); 1198 });
584 1199
585Example 2: Implement a client for a protocol that replies either with 1200Example 2: Implement a client for a protocol that replies either with "OK"
586"OK" and another line or "ERROR" for one request, and 64 bytes for the 1201and another line or "ERROR" for the first request that is sent, and 64
587second request. Due tot he availability of a full queue, we can just 1202bytes for the second request. Due to the availability of a queue, we can
588pipeline sending both requests and manipulate the queue as necessary in 1203just pipeline sending both requests and manipulate the queue as necessary
589the callbacks: 1204in the callbacks.
590 1205
591 # request one 1206When the first callback is called and sees an "OK" response, it will
1207C<unshift> another line-read. This line-read will be queued I<before> the
120864-byte chunk callback.
1209
1210 # request one, returns either "OK + extra line" or "ERROR"
592 $handle->push_write ("request 1\015\012"); 1211 $handle->push_write ("request 1\015\012");
593 1212
594 # we expect "ERROR" or "OK" as response, so push a line read 1213 # we expect "ERROR" or "OK" as response, so push a line read
595 $handle->push_read (line => sub { 1214 $handle->push_read (line => sub {
596 # if we got an "OK", we have to _prepend_ another line, 1215 # if we got an "OK", we have to _prepend_ another line,
603 ... 1222 ...
604 }); 1223 });
605 } 1224 }
606 }); 1225 });
607 1226
608 # request two 1227 # request two, simply returns 64 octets
609 $handle->push_write ("request 2\015\012"); 1228 $handle->push_write ("request 2\015\012");
610 1229
611 # simply read 64 bytes, always 1230 # simply read 64 bytes, always
612 $handle->push_read (chunk => 64, sub { 1231 $handle->push_read (chunk => 64, sub {
613 my $response = $_[1]; 1232 my $response = $_[1];
619=cut 1238=cut
620 1239
621sub _drain_rbuf { 1240sub _drain_rbuf {
622 my ($self) = @_; 1241 my ($self) = @_;
623 1242
1243 # avoid recursion
1244 return if $self->{_skip_drain_rbuf};
1245 local $self->{_skip_drain_rbuf} = 1;
1246
1247 while () {
1248 # we need to use a separate tls read buffer, as we must not receive data while
1249 # we are draining the buffer, and this can only happen with TLS.
1250 $self->{rbuf} .= delete $self->{_tls_rbuf}
1251 if exists $self->{_tls_rbuf};
1252
1253 my $len = length $self->{rbuf};
1254
1255 if (my $cb = shift @{ $self->{_queue} }) {
1256 unless ($cb->($self)) {
1257 # no progress can be made
1258 # (not enough data and no data forthcoming)
1259 $self->_error (Errno::EPIPE, 1), return
1260 if $self->{_eof};
1261
1262 unshift @{ $self->{_queue} }, $cb;
1263 last;
1264 }
1265 } elsif ($self->{on_read}) {
1266 last unless $len;
1267
1268 $self->{on_read}($self);
1269
1270 if (
1271 $len == length $self->{rbuf} # if no data has been consumed
1272 && !@{ $self->{_queue} } # and the queue is still empty
1273 && $self->{on_read} # but we still have on_read
1274 ) {
1275 # no further data will arrive
1276 # so no progress can be made
1277 $self->_error (Errno::EPIPE, 1), return
1278 if $self->{_eof};
1279
1280 last; # more data might arrive
1281 }
1282 } else {
1283 # read side becomes idle
1284 delete $self->{_rw} unless $self->{tls};
1285 last;
1286 }
1287 }
1288
1289 if ($self->{_eof}) {
1290 $self->{on_eof}
1291 ? $self->{on_eof}($self)
1292 : $self->_error (0, 1, "Unexpected end-of-file");
1293
1294 return;
1295 }
1296
624 if ( 1297 if (
625 defined $self->{rbuf_max} 1298 defined $self->{rbuf_max}
626 && $self->{rbuf_max} < length $self->{rbuf} 1299 && $self->{rbuf_max} < length $self->{rbuf}
627 ) { 1300 ) {
628 return $self->_error (&Errno::ENOSPC, 1); 1301 $self->_error (Errno::ENOSPC, 1), return;
629 } 1302 }
630 1303
631 return if $self->{in_drain}; 1304 # may need to restart read watcher
632 local $self->{in_drain} = 1; 1305 unless ($self->{_rw}) {
633 1306 $self->start_read
634 while (my $len = length $self->{rbuf}) { 1307 if $self->{on_read} || @{ $self->{_queue} };
635 no strict 'refs';
636 if (my $cb = shift @{ $self->{_queue} }) {
637 unless ($cb->($self)) {
638 if ($self->{_eof}) {
639 # no progress can be made (not enough data and no data forthcoming)
640 return $self->_error (&Errno::EPIPE, 1);
641 }
642
643 unshift @{ $self->{_queue} }, $cb;
644 return;
645 }
646 } elsif ($self->{on_read}) {
647 $self->{on_read}($self);
648
649 if (
650 $self->{_eof} # if no further data will arrive
651 && $len == length $self->{rbuf} # and no data has been consumed
652 && !@{ $self->{_queue} } # and the queue is still empty
653 && $self->{on_read} # and we still want to read data
654 ) {
655 # then no progress can be made
656 return $self->_error (&Errno::EPIPE, 1);
657 }
658 } else {
659 # read side becomes idle
660 delete $self->{_rw};
661 return;
662 }
663 } 1308 }
664
665 $self->{on_eof}($self)
666 if $self->{_eof} && $self->{on_eof};
667} 1309}
668 1310
669=item $handle->on_read ($cb) 1311=item $handle->on_read ($cb)
670 1312
671This replaces the currently set C<on_read> callback, or clears it (when 1313This replaces the currently set C<on_read> callback, or clears it (when
672the new callback is C<undef>). See the description of C<on_read> in the 1314the new callback is C<undef>). See the description of C<on_read> in the
673constructor. 1315constructor.
674 1316
1317This method may invoke callbacks (and therefore the handle might be
1318destroyed after it returns).
1319
675=cut 1320=cut
676 1321
677sub on_read { 1322sub on_read {
678 my ($self, $cb) = @_; 1323 my ($self, $cb) = @_;
679 1324
680 $self->{on_read} = $cb; 1325 $self->{on_read} = $cb;
1326 $self->_drain_rbuf if $cb;
681} 1327}
682 1328
683=item $handle->rbuf 1329=item $handle->rbuf
684 1330
685Returns 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).
686 1334
687You can access the read buffer directly as the C<< ->{rbuf} >> member, if 1335The only operation allowed on the read buffer (apart from looking at it)
688you want. 1336is removing data from its beginning. Otherwise modifying or appending to
1337it is not allowed and will lead to hard-to-track-down bugs.
689 1338
690NOTE: 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>
691C<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
692automatically 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.
693 1343
694=cut 1344=cut
695 1345
696sub rbuf : lvalue { 1346sub rbuf : lvalue {
697 $_[0]{rbuf} 1347 $_[0]{rbuf}
714 1364
715If enough data was available, then the callback must remove all data it is 1365If enough data was available, then the callback must remove all data it is
716interested in (which can be none at all) and return a true value. After returning 1366interested in (which can be none at all) and return a true value. After returning
717true, it will be removed from the queue. 1367true, it will be removed from the queue.
718 1368
1369These methods may invoke callbacks (and therefore the handle might be
1370destroyed after it returns).
1371
719=cut 1372=cut
720 1373
721our %RH; 1374our %RH;
722 1375
723sub register_read_type($$) { 1376sub register_read_type($$) {
729 my $cb = pop; 1382 my $cb = pop;
730 1383
731 if (@_) { 1384 if (@_) {
732 my $type = shift; 1385 my $type = shift;
733 1386
1387 $cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
734 $cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read") 1388 or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
735 ->($self, $cb, @_); 1389 ->($self, $cb, @_);
736 } 1390 }
737 1391
738 push @{ $self->{_queue} }, $cb; 1392 push @{ $self->{_queue} }, $cb;
739 $self->_drain_rbuf; 1393 $self->_drain_rbuf;
744 my $cb = pop; 1398 my $cb = pop;
745 1399
746 if (@_) { 1400 if (@_) {
747 my $type = shift; 1401 my $type = shift;
748 1402
1403 $cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
749 $cb = ($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")
750 ->($self, $cb, @_); 1405 ->($self, $cb, @_);
751 } 1406 }
752
753 1407
754 unshift @{ $self->{_queue} }, $cb; 1408 unshift @{ $self->{_queue} }, $cb;
755 $self->_drain_rbuf; 1409 $self->_drain_rbuf;
756} 1410}
757 1411
759 1413
760=item $handle->unshift_read (type => @args, $cb) 1414=item $handle->unshift_read (type => @args, $cb)
761 1415
762Instead of providing a callback that parses the data itself you can chose 1416Instead of providing a callback that parses the data itself you can chose
763between a number of predefined parsing formats, for chunks of data, lines 1417between a number of predefined parsing formats, for chunks of data, lines
764etc. 1418etc. You can also specify the (fully qualified) name of a package, in
1419which case AnyEvent tries to load the package and then expects to find the
1420C<anyevent_read_type> function inside (see "custom read types", below).
765 1421
766Predefined types are (if you have ideas for additional types, feel free to 1422Predefined types are (if you have ideas for additional types, feel free to
767drop by and tell us): 1423drop by and tell us):
768 1424
769=over 4 1425=over 4
790 $cb->($_[0], substr $_[0]{rbuf}, 0, $len, ""); 1446 $cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
791 1 1447 1
792 } 1448 }
793}; 1449};
794 1450
795# compatibility with older API
796sub push_read_chunk {
797 $_[0]->push_read (chunk => $_[1], $_[2]);
798}
799
800sub unshift_read_chunk {
801 $_[0]->unshift_read (chunk => $_[1], $_[2]);
802}
803
804=item line => [$eol, ]$cb->($handle, $line, $eol) 1451=item line => [$eol, ]$cb->($handle, $line, $eol)
805 1452
806The callback will be called only once a full line (including the end of 1453The callback will be called only once a full line (including the end of
807line marker, C<$eol>) has been read. This line (excluding the end of line 1454line marker, C<$eol>) has been read. This line (excluding the end of line
808marker) will be passed to the callback as second argument (C<$line>), and 1455marker) will be passed to the callback as second argument (C<$line>), and
823=cut 1470=cut
824 1471
825register_read_type line => sub { 1472register_read_type line => sub {
826 my ($self, $cb, $eol) = @_; 1473 my ($self, $cb, $eol) = @_;
827 1474
828 $eol = qr|(\015?\012)| if @_ < 3; 1475 if (@_ < 3) {
829 $eol = quotemeta $eol unless ref $eol; 1476 # this is more than twice as fast as the generic code below
830 $eol = qr|^(.*?)($eol)|s;
831
832 sub { 1477 sub {
833 $_[0]{rbuf} =~ s/$eol// or return; 1478 $_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
834 1479
835 $cb->($_[0], $1, $2); 1480 $cb->($_[0], $1, $2);
836 1
837 }
838};
839
840# compatibility with older API
841sub push_read_line {
842 my $self = shift;
843 $self->push_read (line => @_);
844}
845
846sub unshift_read_line {
847 my $self = shift;
848 $self->unshift_read (line => @_);
849}
850
851=item netstring => $cb->($handle, $string)
852
853A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
854
855Throws an error with C<$!> set to EBADMSG on format violations.
856
857=cut
858
859register_read_type netstring => sub {
860 my ($self, $cb) = @_;
861
862 sub {
863 unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
864 if ($_[0]{rbuf} =~ /[^0-9]/) {
865 $self->_error (&Errno::EBADMSG);
866 } 1481 1
867 return;
868 } 1482 }
1483 } else {
1484 $eol = quotemeta $eol unless ref $eol;
1485 $eol = qr|^(.*?)($eol)|s;
869 1486
870 my $len = $1; 1487 sub {
1488 $_[0]{rbuf} =~ s/$eol// or return;
871 1489
872 $self->unshift_read (chunk => $len, sub { 1490 $cb->($_[0], $1, $2);
873 my $string = $_[1];
874 $_[0]->unshift_read (chunk => 1, sub {
875 if ($_[1] eq ",") {
876 $cb->($_[0], $string);
877 } else {
878 $self->_error (&Errno::EBADMSG);
879 }
880 }); 1491 1
881 }); 1492 }
882
883 1
884 } 1493 }
885}; 1494};
886 1495
887=item regex => $accept[, $reject[, $skip], $cb->($handle, $data) 1496=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
888 1497
908the receive buffer when neither C<$accept> nor C<$reject> match, 1517the receive buffer when neither C<$accept> nor C<$reject> match,
909and everything preceding and including the match will be accepted 1518and everything preceding and including the match will be accepted
910unconditionally. This is useful to skip large amounts of data that you 1519unconditionally. This is useful to skip large amounts of data that you
911know cannot be matched, so that the C<$accept> or C<$reject> regex do not 1520know cannot be matched, so that the C<$accept> or C<$reject> regex do not
912have to start matching from the beginning. This is purely an optimisation 1521have to start matching from the beginning. This is purely an optimisation
913and 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.
914 1523
915Example: 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
916expect 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
917a 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
918it 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
919required for the accept regex. 1528required for the accept regex.
920 1529
921 $handle->push_read (regex => 1530 $handle->push_read (regex =>
940 return 1; 1549 return 1;
941 } 1550 }
942 1551
943 # reject 1552 # reject
944 if ($reject && $$rbuf =~ $reject) { 1553 if ($reject && $$rbuf =~ $reject) {
945 $self->_error (&Errno::EBADMSG); 1554 $self->_error (Errno::EBADMSG);
946 } 1555 }
947 1556
948 # skip 1557 # skip
949 if ($skip && $$rbuf =~ $skip) { 1558 if ($skip && $$rbuf =~ $skip) {
950 $data .= substr $$rbuf, 0, $+[0], ""; 1559 $data .= substr $$rbuf, 0, $+[0], "";
952 1561
953 () 1562 ()
954 } 1563 }
955}; 1564};
956 1565
1566=item netstring => $cb->($handle, $string)
1567
1568A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
1569
1570Throws an error with C<$!> set to EBADMSG on format violations.
1571
1572=cut
1573
1574register_read_type netstring => sub {
1575 my ($self, $cb) = @_;
1576
1577 sub {
1578 unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
1579 if ($_[0]{rbuf} =~ /[^0-9]/) {
1580 $self->_error (Errno::EBADMSG);
1581 }
1582 return;
1583 }
1584
1585 my $len = $1;
1586
1587 $self->unshift_read (chunk => $len, sub {
1588 my $string = $_[1];
1589 $_[0]->unshift_read (chunk => 1, sub {
1590 if ($_[1] eq ",") {
1591 $cb->($_[0], $string);
1592 } else {
1593 $self->_error (Errno::EBADMSG);
1594 }
1595 });
1596 });
1597
1598 1
1599 }
1600};
1601
1602=item packstring => $format, $cb->($handle, $string)
1603
1604An octet string prefixed with an encoded length. The encoding C<$format>
1605uses the same format as a Perl C<pack> format, but must specify a single
1606integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
1607optional C<!>, C<< < >> or C<< > >> modifier).
1608
1609For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
1610EPP uses a prefix of C<N> (4 octtes).
1611
1612Example: read a block of data prefixed by its length in BER-encoded
1613format (very efficient).
1614
1615 $handle->push_read (packstring => "w", sub {
1616 my ($handle, $data) = @_;
1617 });
1618
1619=cut
1620
1621register_read_type packstring => sub {
1622 my ($self, $cb, $format) = @_;
1623
1624 sub {
1625 # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
1626 defined (my $len = eval { unpack $format, $_[0]{rbuf} })
1627 or return;
1628
1629 $format = length pack $format, $len;
1630
1631 # bypass unshift if we already have the remaining chunk
1632 if ($format + $len <= length $_[0]{rbuf}) {
1633 my $data = substr $_[0]{rbuf}, $format, $len;
1634 substr $_[0]{rbuf}, 0, $format + $len, "";
1635 $cb->($_[0], $data);
1636 } else {
1637 # remove prefix
1638 substr $_[0]{rbuf}, 0, $format, "";
1639
1640 # read remaining chunk
1641 $_[0]->unshift_read (chunk => $len, $cb);
1642 }
1643
1644 1
1645 }
1646};
1647
957=item json => $cb->($handle, $hash_or_arrayref) 1648=item json => $cb->($handle, $hash_or_arrayref)
958 1649
959Reads a JSON object or array, decodes it and passes it to the callback. 1650Reads a JSON object or array, decodes it and passes it to the
1651callback. When a parse error occurs, an C<EBADMSG> error will be raised.
960 1652
961If a C<json> object was passed to the constructor, then that will be used 1653If a C<json> object was passed to the constructor, then that will be used
962for the final decode, otherwise it will create a JSON coder expecting UTF-8. 1654for the final decode, otherwise it will create a JSON coder expecting UTF-8.
963 1655
964This read type uses the incremental parser available with JSON version 1656This read type uses the incremental parser available with JSON version
971the C<json> write type description, above, for an actual example. 1663the C<json> write type description, above, for an actual example.
972 1664
973=cut 1665=cut
974 1666
975register_read_type json => sub { 1667register_read_type json => sub {
976 my ($self, $cb, $accept, $reject, $skip) = @_; 1668 my ($self, $cb) = @_;
977 1669
978 require JSON; 1670 my $json = $self->{json} ||= json_coder;
979 1671
980 my $data; 1672 my $data;
981 my $rbuf = \$self->{rbuf}; 1673 my $rbuf = \$self->{rbuf};
982 1674
983 my $json = $self->{json} ||= JSON->new->utf8;
984
985 sub { 1675 sub {
986 my $ref = $json->incr_parse ($self->{rbuf}); 1676 my $ref = eval { $json->incr_parse ($self->{rbuf}) };
987 1677
988 if ($ref) { 1678 if ($ref) {
989 $self->{rbuf} = $json->incr_text; 1679 $self->{rbuf} = $json->incr_text;
990 $json->incr_text = ""; 1680 $json->incr_text = "";
991 $cb->($self, $ref); 1681 $cb->($self, $ref);
992 1682
993 1 1683 1
1684 } elsif ($@) {
1685 # error case
1686 $json->incr_skip;
1687
1688 $self->{rbuf} = $json->incr_text;
1689 $json->incr_text = "";
1690
1691 $self->_error (Errno::EBADMSG);
1692
1693 ()
994 } else { 1694 } else {
995 $self->{rbuf} = ""; 1695 $self->{rbuf} = "";
1696
996 () 1697 ()
997 } 1698 }
998 } 1699 }
999}; 1700};
1000 1701
1702=item storable => $cb->($handle, $ref)
1703
1704Deserialises a L<Storable> frozen representation as written by the
1705C<storable> write type (BER-encoded length prefix followed by nfreeze'd
1706data).
1707
1708Raises C<EBADMSG> error if the data could not be decoded.
1709
1710=cut
1711
1712register_read_type storable => sub {
1713 my ($self, $cb) = @_;
1714
1715 require Storable;
1716
1717 sub {
1718 # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
1719 defined (my $len = eval { unpack "w", $_[0]{rbuf} })
1720 or return;
1721
1722 my $format = length pack "w", $len;
1723
1724 # bypass unshift if we already have the remaining chunk
1725 if ($format + $len <= length $_[0]{rbuf}) {
1726 my $data = substr $_[0]{rbuf}, $format, $len;
1727 substr $_[0]{rbuf}, 0, $format + $len, "";
1728 $cb->($_[0], Storable::thaw ($data));
1729 } else {
1730 # remove prefix
1731 substr $_[0]{rbuf}, 0, $format, "";
1732
1733 # read remaining chunk
1734 $_[0]->unshift_read (chunk => $len, sub {
1735 if (my $ref = eval { Storable::thaw ($_[1]) }) {
1736 $cb->($_[0], $ref);
1737 } else {
1738 $self->_error (Errno::EBADMSG);
1739 }
1740 });
1741 }
1742
1743 1
1744 }
1745};
1746
1001=back 1747=back
1002 1748
1003=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args) 1749=item custom read types - Package::anyevent_read_type $handle, $cb, @args
1004 1750
1005This function (not method) lets you add your own types to C<push_read>. 1751Instead of one of the predefined types, you can also specify the name
1752of a package. AnyEvent will try to load the package and then expects to
1753find a function named C<anyevent_read_type> inside. If it isn't found, it
1754progressively tries to load the parent package until it either finds the
1755function (good) or runs out of packages (bad).
1006 1756
1007Whenever the given C<type> is used, C<push_read> will invoke the code 1757Whenever this type is used, C<push_read> will invoke the function with the
1008reference with the handle object, the callback and the remaining 1758handle object, the original callback and the remaining arguments.
1009arguments.
1010 1759
1011The code reference is supposed to return a callback (usually a closure) 1760The function is supposed to return a callback (usually a closure) that
1012that works as a plain read callback (see C<< ->push_read ($cb) >>). 1761works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
1762mentally treat the function as a "configurable read type to read callback"
1763converter.
1013 1764
1014It should invoke the passed callback when it is done reading (remember to 1765It should invoke the original callback when it is done reading (remember
1015pass C<$handle> as first argument as all other callbacks do that). 1766to pass C<$handle> as first argument as all other callbacks do that,
1767although there is no strict requirement on this).
1016 1768
1017Note that this is a function, and all types registered this way will be
1018global, so try to use unique names.
1019
1020For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>, 1769For examples, see the source of this module (F<perldoc -m
1021search for C<register_read_type>)). 1770AnyEvent::Handle>, search for C<register_read_type>)).
1022 1771
1023=item $handle->stop_read 1772=item $handle->stop_read
1024 1773
1025=item $handle->start_read 1774=item $handle->start_read
1026 1775
1027In rare cases you actually do not want to read anything from the 1776In rare cases you actually do not want to read anything from the
1028socket. In this case you can call C<stop_read>. Neither C<on_read> no 1777socket. In this case you can call C<stop_read>. Neither C<on_read> nor
1029any queued callbacks will be executed then. To start reading again, call 1778any queued callbacks will be executed then. To start reading again, call
1030C<start_read>. 1779C<start_read>.
1031 1780
1781Note that AnyEvent::Handle will automatically C<start_read> for you when
1782you change the C<on_read> callback or push/unshift a read callback, and it
1783will automatically C<stop_read> for you when neither C<on_read> is set nor
1784there are any read requests in the queue.
1785
1786In older versions of this module (<= 5.3), these methods had no effect,
1787as TLS does not support half-duplex connections. In current versions they
1788work as expected, as this behaviour is required to avoid certain resource
1789attacks, where the program would be forced to read (and buffer) arbitrary
1790amounts of data before being able to send some data. The drawback is that
1791some readings of the the SSL/TLS specifications basically require this
1792attack to be working, as SSL/TLS implementations might stall sending data
1793during a rehandshake.
1794
1795As a guideline, during the initial handshake, you should not stop reading,
1796and as a client, it might cause problems, depending on your applciation.
1797
1032=cut 1798=cut
1033 1799
1034sub stop_read { 1800sub stop_read {
1035 my ($self) = @_; 1801 my ($self) = @_;
1036 1802
1038} 1804}
1039 1805
1040sub start_read { 1806sub start_read {
1041 my ($self) = @_; 1807 my ($self) = @_;
1042 1808
1043 unless ($self->{_rw} || $self->{_eof}) { 1809 unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
1044 Scalar::Util::weaken $self; 1810 Scalar::Util::weaken $self;
1045 1811
1046 $self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub { 1812 $self->{_rw} = AE::io $self->{fh}, 0, sub {
1047 my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf}; 1813 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1048 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf; 1814 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
1049 1815
1050 if ($len > 0) { 1816 if ($len > 0) {
1051 $self->{_activity} = AnyEvent->now; 1817 $self->{_activity} = $self->{_ractivity} = AE::now;
1052 1818
1053 $self->{filter_r} 1819 if ($self->{tls}) {
1054 ? $self->{filter_r}($self, $rbuf) 1820 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1821
1822 &_dotls ($self);
1823 } else {
1055 : $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);
1831 }
1056 1832
1057 } elsif (defined $len) { 1833 } elsif (defined $len) {
1058 delete $self->{_rw}; 1834 delete $self->{_rw};
1059 $self->{_eof} = 1; 1835 $self->{_eof} = 1;
1060 $self->_drain_rbuf; 1836 $self->_drain_rbuf;
1061 1837
1062 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) { 1838 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
1063 return $self->_error ($!, 1); 1839 return $self->_error ($!, 1);
1064 } 1840 }
1065 }); 1841 };
1066 } 1842 }
1067} 1843}
1068 1844
1845our $ERROR_SYSCALL;
1846our $ERROR_WANT_READ;
1847
1848sub _tls_error {
1849 my ($self, $err) = @_;
1850
1851 return $self->_error ($!, 1)
1852 if $err == Net::SSLeay::ERROR_SYSCALL ();
1853
1854 my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
1855
1856 # reduce error string to look less scary
1857 $err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
1858
1859 if ($self->{_on_starttls}) {
1860 (delete $self->{_on_starttls})->($self, undef, $err);
1861 &_freetls;
1862 } else {
1863 &_freetls;
1864 $self->_error (Errno::EPROTO, 1, $err);
1865 }
1866}
1867
1868# poll the write BIO and send the data if applicable
1869# also decode read data if possible
1870# this is basiclaly our TLS state machine
1871# more efficient implementations are possible with openssl,
1872# but not with the buggy and incomplete Net::SSLeay.
1069sub _dotls { 1873sub _dotls {
1070 my ($self) = @_; 1874 my ($self) = @_;
1071 1875
1876 my $tmp;
1877
1072 if (length $self->{_tls_wbuf}) { 1878 if (length $self->{_tls_wbuf}) {
1073 while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) { 1879 while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
1074 substr $self->{_tls_wbuf}, 0, $len, ""; 1880 substr $self->{_tls_wbuf}, 0, $tmp, "";
1075 } 1881 }
1076 }
1077 1882
1883 $tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
1884 return $self->_tls_error ($tmp)
1885 if $tmp != $ERROR_WANT_READ
1886 && ($tmp != $ERROR_SYSCALL || $!);
1887 }
1888
1889 while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
1890 unless (length $tmp) {
1891 $self->{_on_starttls}
1892 and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
1893 &_freetls;
1894
1895 if ($self->{on_stoptls}) {
1896 $self->{on_stoptls}($self);
1897 return;
1898 } else {
1899 # let's treat SSL-eof as we treat normal EOF
1900 delete $self->{_rw};
1901 $self->{_eof} = 1;
1902 }
1903 }
1904
1905 $self->{_tls_rbuf} .= $tmp;
1906 $self->_drain_rbuf;
1907 $self->{tls} or return; # tls session might have gone away in callback
1908 }
1909
1910 $tmp = Net::SSLeay::get_error ($self->{tls}, -1);
1911 return $self->_tls_error ($tmp)
1912 if $tmp != $ERROR_WANT_READ
1913 && ($tmp != $ERROR_SYSCALL || $!);
1914
1078 if (defined (my $buf = Net::SSLeay::BIO_read ($self->{_wbio}))) { 1915 while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1079 $self->{wbuf} .= $buf; 1916 $self->{wbuf} .= $tmp;
1080 $self->_drain_wbuf; 1917 $self->_drain_wbuf;
1918 $self->{tls} or return; # tls session might have gone away in callback
1081 } 1919 }
1082 1920
1083 while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) { 1921 $self->{_on_starttls}
1084 $self->{rbuf} .= $buf; 1922 and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
1085 $self->_drain_rbuf; 1923 and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
1086 }
1087
1088 my $err = Net::SSLeay::get_error ($self->{tls}, -1);
1089
1090 if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
1091 if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
1092 return $self->_error ($!, 1);
1093 } elsif ($err == Net::SSLeay::ERROR_SSL ()) {
1094 return $self->_error (&Errno::EIO, 1);
1095 }
1096
1097 # all others are fine for our purposes
1098 }
1099} 1924}
1100 1925
1101=item $handle->starttls ($tls[, $tls_ctx]) 1926=item $handle->starttls ($tls[, $tls_ctx])
1102 1927
1103Instead of starting TLS negotiation immediately when the AnyEvent::Handle 1928Instead of starting TLS negotiation immediately when the AnyEvent::Handle
1104object is created, you can also do that at a later time by calling 1929object is created, you can also do that at a later time by calling
1105C<starttls>. 1930C<starttls>.
1106 1931
1932Starting TLS is currently an asynchronous operation - when you push some
1933write data and then call C<< ->starttls >> then TLS negotiation will start
1934immediately, after which the queued write data is then sent.
1935
1107The first argument is the same as the C<tls> constructor argument (either 1936The first argument is the same as the C<tls> constructor argument (either
1108C<"connect">, C<"accept"> or an existing Net::SSLeay object). 1937C<"connect">, C<"accept"> or an existing Net::SSLeay object).
1109 1938
1110The second argument is the optional C<Net::SSLeay::CTX> object that is 1939The second argument is the optional C<AnyEvent::TLS> object that is used
1111used when AnyEvent::Handle has to create its own TLS connection object. 1940when AnyEvent::Handle has to create its own TLS connection object, or
1941a hash reference with C<< key => value >> pairs that will be used to
1942construct a new context.
1112 1943
1113The TLS connection object will end up in C<< $handle->{tls} >> after this 1944The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
1114call and can be used or changed to your liking. Note that the handshake 1945context in C<< $handle->{tls_ctx} >> after this call and can be used or
1115might have already started when this function returns. 1946changed to your liking. Note that the handshake might have already started
1947when this function returns.
1116 1948
1949Due to bugs in OpenSSL, it might or might not be possible to do multiple
1950handshakes on the same stream. It is best to not attempt to use the
1951stream after stopping TLS.
1952
1953This method may invoke callbacks (and therefore the handle might be
1954destroyed after it returns).
1955
1117=cut 1956=cut
1957
1958our %TLS_CACHE; #TODO not yet documented, should we?
1118 1959
1119sub starttls { 1960sub starttls {
1120 my ($self, $ssl, $ctx) = @_; 1961 my ($self, $tls, $ctx) = @_;
1121 1962
1122 $self->stoptls; 1963 Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
1964 if $self->{tls};
1123 1965
1124 if ($ssl eq "accept") { 1966 $self->{tls} = $tls;
1125 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1967 $self->{tls_ctx} = $ctx if @_ > 2;
1126 Net::SSLeay::set_accept_state ($ssl); 1968
1127 } elsif ($ssl eq "connect") { 1969 return unless $self->{fh};
1128 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1970
1129 Net::SSLeay::set_connect_state ($ssl); 1971 require Net::SSLeay;
1972
1973 $ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
1974 $ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
1975
1976 $tls = delete $self->{tls};
1977 $ctx = $self->{tls_ctx};
1978
1979 local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
1980
1981 if ("HASH" eq ref $ctx) {
1982 require AnyEvent::TLS;
1983
1984 if ($ctx->{cache}) {
1985 my $key = $ctx+0;
1986 $ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
1987 } else {
1988 $ctx = new AnyEvent::TLS %$ctx;
1989 }
1990 }
1130 } 1991
1131 1992 $self->{tls_ctx} = $ctx || TLS_CTX ();
1132 $self->{tls} = $ssl; 1993 $self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
1133 1994
1134 # basically, this is deep magic (because SSL_read should have the same issues) 1995 # basically, this is deep magic (because SSL_read should have the same issues)
1135 # but the openssl maintainers basically said: "trust us, it just works". 1996 # but the openssl maintainers basically said: "trust us, it just works".
1136 # (unfortunately, we have to hardcode constants because the abysmally misdesigned 1997 # (unfortunately, we have to hardcode constants because the abysmally misdesigned
1137 # and mismaintained ssleay-module doesn't even offer them). 1998 # and mismaintained ssleay-module doesn't even offer them).
1138 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html 1999 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
2000 #
2001 # in short: this is a mess.
2002 #
2003 # note that we do not try to keep the length constant between writes as we are required to do.
2004 # we assume that most (but not all) of this insanity only applies to non-blocking cases,
2005 # and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
2006 # have identity issues in that area.
1139 Net::SSLeay::CTX_set_mode ($self->{tls}, 2007# Net::SSLeay::CTX_set_mode ($ssl,
1140 (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1) 2008# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
1141 | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2)); 2009# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
2010 Net::SSLeay::CTX_set_mode ($tls, 1|2);
1142 2011
1143 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 2012 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1144 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 2013 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1145 2014
2015 Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
2016 $self->{rbuf} = "";
2017
1146 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio}); 2018 Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
1147 2019
1148 $self->{filter_w} = sub { 2020 $self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
1149 $_[0]{_tls_wbuf} .= ${$_[1]}; 2021 if $self->{on_starttls};
1150 &_dotls; 2022
1151 }; 2023 &_dotls; # need to trigger the initial handshake
1152 $self->{filter_r} = sub { 2024 $self->start_read; # make sure we actually do read
1153 Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
1154 &_dotls;
1155 };
1156} 2025}
1157 2026
1158=item $handle->stoptls 2027=item $handle->stoptls
1159 2028
1160Destroys the SSL connection, if any. Partial read or write data will be 2029Shuts down the SSL connection - this makes a proper EOF handshake by
1161lost. 2030sending a close notify to the other side, but since OpenSSL doesn't
2031support non-blocking shut downs, it is not guaranteed that you can re-use
2032the stream afterwards.
2033
2034This method may invoke callbacks (and therefore the handle might be
2035destroyed after it returns).
1162 2036
1163=cut 2037=cut
1164 2038
1165sub stoptls { 2039sub stoptls {
1166 my ($self) = @_; 2040 my ($self) = @_;
1167 2041
1168 Net::SSLeay::free (delete $self->{tls}) if $self->{tls}; 2042 if ($self->{tls} && $self->{fh}) {
2043 Net::SSLeay::shutdown ($self->{tls});
1169 2044
1170 delete $self->{_rbio}; 2045 &_dotls;
1171 delete $self->{_wbio}; 2046
1172 delete $self->{_tls_wbuf}; 2047# # we don't give a shit. no, we do, but we can't. no...#d#
1173 delete $self->{filter_r}; 2048# # we, we... have to use openssl :/#d#
1174 delete $self->{filter_w}; 2049# &_freetls;#d#
2050 }
1175} 2051}
2052
2053sub _freetls {
2054 my ($self) = @_;
2055
2056 return unless $self->{tls};
2057
2058 $self->{tls_ctx}->_put_session (delete $self->{tls})
2059 if $self->{tls} > 0;
2060
2061 delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
2062}
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;
1176 2076
1177sub DESTROY { 2077sub DESTROY {
1178 my $self = shift; 2078 my ($self) = @_;
1179 2079
1180 $self->stoptls; 2080 &_freetls;
2081
2082 my $linger = exists $self->{linger} ? $self->{linger} : 3600;
2083
2084 if ($linger && length $self->{wbuf} && $self->{fh}) {
2085 my $fh = delete $self->{fh};
2086 my $wbuf = delete $self->{wbuf};
2087
2088 my @linger;
2089
2090 push @linger, AE::io $fh, 1, sub {
2091 my $len = syswrite $fh, $wbuf, length $wbuf;
2092
2093 if ($len > 0) {
2094 substr $wbuf, 0, $len, "";
2095 } elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
2096 @linger = (); # end
2097 }
2098 };
2099 push @linger, AE::timer $linger, 0, sub {
2100 @linger = ();
2101 };
2102 }
1181} 2103}
2104
2105=item $handle->destroy
2106
2107Shuts down the handle object as much as possible - this call ensures that
2108no further callbacks will be invoked and as many resources as possible
2109will be freed. Any method you will call on the handle object after
2110destroying it in this way will be silently ignored (and it will return the
2111empty list).
2112
2113Normally, you can just "forget" any references to an AnyEvent::Handle
2114object and it will simply shut down. This works in fatal error and EOF
2115callbacks, as well as code outside. It does I<NOT> work in a read or write
2116callback, so when you want to destroy the AnyEvent::Handle object from
2117within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
2118that case.
2119
2120Destroying the handle object in this way has the advantage that callbacks
2121will be removed as well, so if those are the only reference holders (as
2122is common), then one doesn't need to do anything special to break any
2123reference cycles.
2124
2125The handle might still linger in the background and write out remaining
2126data, as specified by the C<linger> option, however.
2127
2128=cut
2129
2130sub destroy {
2131 my ($self) = @_;
2132
2133 $self->DESTROY;
2134 %$self = ();
2135 bless $self, "AnyEvent::Handle::destroyed";
2136}
2137
2138sub AnyEvent::Handle::destroyed::AUTOLOAD {
2139 #nop
2140}
2141
2142=item $handle->destroyed
2143
2144Returns false as long as the handle hasn't been destroyed by a call to C<<
2145->destroy >>, true otherwise.
2146
2147Can be useful to decide whether the handle is still valid after some
2148callback possibly destroyed the handle. For example, C<< ->push_write >>,
2149C<< ->starttls >> and other methods can call user callbacks, which in turn
2150can destroy the handle, so work can be avoided by checking sometimes:
2151
2152 $hdl->starttls ("accept");
2153 return if $hdl->destroyed;
2154 $hdl->push_write (...
2155
2156Note that the call to C<push_write> will silently be ignored if the handle
2157has been destroyed, so often you can just ignore the possibility of the
2158handle being destroyed.
2159
2160=cut
2161
2162sub destroyed { 0 }
2163sub AnyEvent::Handle::destroyed::destroyed { 1 }
1182 2164
1183=item AnyEvent::Handle::TLS_CTX 2165=item AnyEvent::Handle::TLS_CTX
1184 2166
1185This function creates and returns the Net::SSLeay::CTX object used by 2167This function creates and returns the AnyEvent::TLS object used by default
1186default for TLS mode. 2168for TLS mode.
1187 2169
1188The context is created like this: 2170The context is created by calling L<AnyEvent::TLS> without any arguments.
1189
1190 Net::SSLeay::load_error_strings;
1191 Net::SSLeay::SSLeay_add_ssl_algorithms;
1192 Net::SSLeay::randomize;
1193
1194 my $CTX = Net::SSLeay::CTX_new;
1195
1196 Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
1197 2171
1198=cut 2172=cut
1199 2173
1200our $TLS_CTX; 2174our $TLS_CTX;
1201 2175
1202sub TLS_CTX() { 2176sub TLS_CTX() {
1203 $TLS_CTX || do { 2177 $TLS_CTX ||= do {
1204 require Net::SSLeay; 2178 require AnyEvent::TLS;
1205 2179
1206 Net::SSLeay::load_error_strings (); 2180 new AnyEvent::TLS
1207 Net::SSLeay::SSLeay_add_ssl_algorithms ();
1208 Net::SSLeay::randomize ();
1209
1210 $TLS_CTX = Net::SSLeay::CTX_new ();
1211
1212 Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
1213
1214 $TLS_CTX
1215 } 2181 }
1216} 2182}
1217 2183
1218=back 2184=back
2185
2186
2187=head1 NONFREQUENTLY ASKED QUESTIONS
2188
2189=over 4
2190
2191=item I C<undef> the AnyEvent::Handle reference inside my callback and
2192still get further invocations!
2193
2194That's because AnyEvent::Handle keeps a reference to itself when handling
2195read or write callbacks.
2196
2197It is only safe to "forget" the reference inside EOF or error callbacks,
2198from within all other callbacks, you need to explicitly call the C<<
2199->destroy >> method.
2200
2201=item Why is my C<on_eof> callback never called?
2202
2203Probably because your C<on_error> callback is being called instead: When
2204you have outstanding requests in your read queue, then an EOF is
2205considered an error as you clearly expected some data.
2206
2207To avoid this, make sure you have an empty read queue whenever your handle
2208is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
2209an C<on_read> handler that simply pushes the first read requests in the
2210queue.
2211
2212See also the next question, which explains this in a bit more detail.
2213
2214=item How can I serve requests in a loop?
2215
2216Most protocols consist of some setup phase (authentication for example)
2217followed by a request handling phase, where the server waits for requests
2218and handles them, in a loop.
2219
2220There are two important variants: The first (traditional, better) variant
2221handles requests until the server gets some QUIT command, causing it to
2222close the connection first (highly desirable for a busy TCP server). A
2223client dropping the connection is an error, which means this variant can
2224detect an unexpected detection close.
2225
2226To handle this case, always make sure you have a on-empty read queue, by
2227pushing the "read request start" handler on it:
2228
2229 # we assume a request starts with a single line
2230 my @start_request; @start_request = (line => sub {
2231 my ($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, $line) = @_;
2273
2274 ... handle request
2275
2276 # do nothing special when the request has been handled, just
2277 # let the request queue go empty.
2278 });
2279 });
2280
2281=item I get different callback invocations in TLS mode/Why can't I pause
2282reading?
2283
2284Unlike, say, TCP, TLS connections do not consist of two independent
2285communication channels, one for each direction. Or put differently, the
2286read and write directions are not independent of each other: you cannot
2287write data unless you are also prepared to read, and vice versa.
2288
2289This means that, in TLS mode, you might get C<on_error> or C<on_eof>
2290callback invocations when you are not expecting any read data - the reason
2291is that AnyEvent::Handle always reads in TLS mode.
2292
2293During the connection, you have to make sure that you always have a
2294non-empty read-queue, or an C<on_read> watcher. At the end of the
2295connection (or when you no longer want to use it) you can call the
2296C<destroy> method.
2297
2298=item How do I read data until the other side closes the connection?
2299
2300If you just want to read your data into a perl scalar, the easiest way
2301to achieve this is by setting an C<on_read> callback that does nothing,
2302clearing the C<on_eof> callback and in the C<on_error> callback, the data
2303will be in C<$_[0]{rbuf}>:
2304
2305 $handle->on_read (sub { });
2306 $handle->on_eof (undef);
2307 $handle->on_error (sub {
2308 my $data = delete $_[0]{rbuf};
2309 });
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
2315The reason to use C<on_error> is that TCP connections, due to latencies
2316and packets loss, might get closed quite violently with an error, when in
2317fact all data has been received.
2318
2319It is usually better to use acknowledgements when transferring data,
2320to make sure the other side hasn't just died and you got the data
2321intact. This is also one reason why so many internet protocols have an
2322explicit QUIT command.
2323
2324=item I don't want to destroy the handle too early - how do I wait until
2325all data has been written?
2326
2327After writing your last bits of data, set the C<on_drain> callback
2328and destroy the handle in there - with the default setting of
2329C<low_water_mark> this will be called precisely when all data has been
2330written to the socket:
2331
2332 $handle->push_write (...);
2333 $handle->on_drain (sub {
2334 warn "all data submitted to the kernel\n";
2335 undef $handle;
2336 });
2337
2338If you just want to queue some data and then signal EOF to the other side,
2339consider using C<< ->push_shutdown >> instead.
2340
2341=item I want to contact a TLS/SSL server, I don't care about security.
2342
2343If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
2344connect to it and then create the AnyEvent::Handle with the C<tls>
2345parameter:
2346
2347 tcp_connect $host, $port, sub {
2348 my ($fh) = @_;
2349
2350 my $handle = new AnyEvent::Handle
2351 fh => $fh,
2352 tls => "connect",
2353 on_error => sub { ... };
2354
2355 $handle->push_write (...);
2356 };
2357
2358=item I want to contact a TLS/SSL server, I do care about security.
2359
2360Then you should additionally enable certificate verification, including
2361peername verification, if the protocol you use supports it (see
2362L<AnyEvent::TLS>, C<verify_peername>).
2363
2364E.g. for HTTPS:
2365
2366 tcp_connect $host, $port, sub {
2367 my ($fh) = @_;
2368
2369 my $handle = new AnyEvent::Handle
2370 fh => $fh,
2371 peername => $host,
2372 tls => "connect",
2373 tls_ctx => { verify => 1, verify_peername => "https" },
2374 ...
2375
2376Note that you must specify the hostname you connected to (or whatever
2377"peername" the protocol needs) as the C<peername> argument, otherwise no
2378peername verification will be done.
2379
2380The above will use the system-dependent default set of trusted CA
2381certificates. If you want to check against a specific CA, add the
2382C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
2383
2384 tls_ctx => {
2385 verify => 1,
2386 verify_peername => "https",
2387 ca_file => "my-ca-cert.pem",
2388 },
2389
2390=item I want to create a TLS/SSL server, how do I do that?
2391
2392Well, you first need to get a server certificate and key. You have
2393three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
2394self-signed certificate (cheap. check the search engine of your choice,
2395there are many tutorials on the net) or c) make your own CA (tinyca2 is a
2396nice program for that purpose).
2397
2398Then create a file with your private key (in PEM format, see
2399L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
2400file should then look like this:
2401
2402 -----BEGIN RSA PRIVATE KEY-----
2403 ...header data
2404 ... lots of base64'y-stuff
2405 -----END RSA PRIVATE KEY-----
2406
2407 -----BEGIN CERTIFICATE-----
2408 ... lots of base64'y-stuff
2409 -----END CERTIFICATE-----
2410
2411The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
2412specify this file as C<cert_file>:
2413
2414 tcp_server undef, $port, sub {
2415 my ($fh) = @_;
2416
2417 my $handle = new AnyEvent::Handle
2418 fh => $fh,
2419 tls => "accept",
2420 tls_ctx => { cert_file => "my-server-keycert.pem" },
2421 ...
2422
2423When you have intermediate CA certificates that your clients might not
2424know about, just append them to the C<cert_file>.
2425
2426=back
2427
1219 2428
1220=head1 SUBCLASSING AnyEvent::Handle 2429=head1 SUBCLASSING AnyEvent::Handle
1221 2430
1222In many cases, you might want to subclass AnyEvent::Handle. 2431In many cases, you might want to subclass AnyEvent::Handle.
1223 2432
1227=over 4 2436=over 4
1228 2437
1229=item * all constructor arguments become object members. 2438=item * all constructor arguments become object members.
1230 2439
1231At least initially, when you pass a C<tls>-argument to the constructor it 2440At least initially, when you pass a C<tls>-argument to the constructor it
1232will end up in C<< $handle->{tls} >>. Those members might be changes or 2441will end up in C<< $handle->{tls} >>. Those members might be changed or
1233mutated later on (for example C<tls> will hold the TLS connection object). 2442mutated later on (for example C<tls> will hold the TLS connection object).
1234 2443
1235=item * other object member names are prefixed with an C<_>. 2444=item * other object member names are prefixed with an C<_>.
1236 2445
1237All object members not explicitly documented (internal use) are prefixed 2446All object members not explicitly documented (internal use) are prefixed
1240 2449
1241=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
1242are free to use in subclasses. 2451are free to use in subclasses.
1243 2452
1244Of course, new versions of AnyEvent::Handle may introduce more "public" 2453Of course, new versions of AnyEvent::Handle may introduce more "public"
1245member variables, but thats just life, at least it is documented. 2454member variables, but that's just life. At least it is documented.
1246 2455
1247=back 2456=back
1248 2457
1249=head1 AUTHOR 2458=head1 AUTHOR
1250 2459

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