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Revision 1.56 by root, Wed Jun 4 09:55:16 2008 UTC vs.
Revision 1.218 by root, Thu Feb 24 12:04:20 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 = 4.12;
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 # callback 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 return unless $self; # ->error could have destroyed $self
353
354 $self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
355 delete $self->{_tw};
356 $self->_timeout;
357 });
358 } else {
359 delete $self->{_tw};
360 } 868 }
361} 869}
362 870
363############################################################################# 871#############################################################################
364 872
380=item $handle->on_drain ($cb) 888=item $handle->on_drain ($cb)
381 889
382Sets 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
383C<on_drain> in the constructor). 891C<on_drain> in the constructor).
384 892
893This method may invoke callbacks (and therefore the handle might be
894destroyed after it returns).
895
385=cut 896=cut
386 897
387sub on_drain { 898sub on_drain {
388 my ($self, $cb) = @_; 899 my ($self, $cb) = @_;
389 900
390 $self->{on_drain} = $cb; 901 $self->{on_drain} = $cb;
391 902
392 $cb->($self) 903 $cb->($self)
393 if $cb && $self->{low_water_mark} >= length $self->{wbuf}; 904 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
394} 905}
395 906
396=item $handle->push_write ($data) 907=item $handle->push_write ($data)
397 908
398Queues 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
399want (only limited by the available memory), as C<AnyEvent::Handle> 910you want (only limited by the available memory and C<wbuf_max>), as
400buffers 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).
401 915
402=cut 916=cut
403 917
404sub _drain_wbuf { 918sub _drain_wbuf {
405 my ($self) = @_; 919 my ($self) = @_;
409 Scalar::Util::weaken $self; 923 Scalar::Util::weaken $self;
410 924
411 my $cb = sub { 925 my $cb = sub {
412 my $len = syswrite $self->{fh}, $self->{wbuf}; 926 my $len = syswrite $self->{fh}, $self->{wbuf};
413 927
414 if ($len >= 0) { 928 if (defined $len) {
415 substr $self->{wbuf}, 0, $len, ""; 929 substr $self->{wbuf}, 0, $len, "";
416 930
417 $self->{_activity} = AnyEvent->now; 931 $self->{_activity} = $self->{_wactivity} = AE::now;
418 932
419 $self->{on_drain}($self) 933 $self->{on_drain}($self)
420 if $self->{low_water_mark} >= length $self->{wbuf} 934 if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
421 && $self->{on_drain}; 935 && $self->{on_drain};
422 936
423 delete $self->{_ww} unless length $self->{wbuf}; 937 delete $self->{_ww} unless length $self->{wbuf};
424 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) { 938 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
425 $self->_error ($!, 1); 939 $self->_error ($!, 1);
426 } 940 }
427 }; 941 };
428 942
429 # try to write data immediately 943 # try to write data immediately
430 $cb->(); 944 $cb->() unless $self->{autocork};
431 945
432 # if still data left in wbuf, we need to poll 946 # if still data left in wbuf, we need to poll
433 $self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb) 947 $self->{_ww} = AE::io $self->{fh}, 1, $cb
434 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 }
435 }; 956 };
436} 957}
437 958
438our %WH; 959our %WH;
439 960
961# deprecated
440sub register_write_type($$) { 962sub register_write_type($$) {
441 $WH{$_[0]} = $_[1]; 963 $WH{$_[0]} = $_[1];
442} 964}
443 965
444sub push_write { 966sub push_write {
445 my $self = shift; 967 my $self = shift;
446 968
447 if (@_ > 1) { 969 if (@_ > 1) {
448 my $type = shift; 970 my $type = shift;
449 971
972 @_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
450 @_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write") 973 or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
451 ->($self, @_); 974 ->($self, @_);
452 } 975 }
453 976
977 # we downgrade here to avoid hard-to-track-down bugs,
978 # and diagnose the problem earlier and better.
979
454 if ($self->{filter_w}) { 980 if ($self->{tls}) {
455 $self->{filter_w}($self, \$_[0]); 981 utf8::downgrade $self->{_tls_wbuf} .= $_[0];
982 &_dotls ($self) if $self->{fh};
456 } else { 983 } else {
457 $self->{wbuf} .= $_[0]; 984 utf8::downgrade $self->{wbuf} .= $_[0];
458 $self->_drain_wbuf; 985 $self->_drain_wbuf if $self->{fh};
459 } 986 }
460} 987}
461 988
462=item $handle->push_write (type => @args) 989=item $handle->push_write (type => @args)
463 990
464Instead of formatting your data yourself, you can also let this module do 991Instead of formatting your data yourself, you can also let this module
465the job by specifying a type and type-specific arguments. 992do the job by specifying a type and type-specific arguments. You
993can also specify the (fully qualified) name of a package, in which
994case AnyEvent tries to load the package and then expects to find the
995C<anyevent_write_type> function inside (see "custom write types", below).
466 996
467Predefined types are (if you have ideas for additional types, feel free to 997Predefined types are (if you have ideas for additional types, feel free to
468drop by and tell us): 998drop by and tell us):
469 999
470=over 4 1000=over 4
477=cut 1007=cut
478 1008
479register_write_type netstring => sub { 1009register_write_type netstring => sub {
480 my ($self, $string) = @_; 1010 my ($self, $string) = @_;
481 1011
482 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
483}; 1028};
484 1029
485=item json => $array_or_hashref 1030=item json => $array_or_hashref
486 1031
487Encodes the given hash or array reference into a JSON object. Unless you 1032Encodes the given hash or array reference into a JSON object. Unless you
512Other languages could read single lines terminated by a newline and pass 1057Other languages could read single lines terminated by a newline and pass
513this line into their JSON decoder of choice. 1058this line into their JSON decoder of choice.
514 1059
515=cut 1060=cut
516 1061
1062sub json_coder() {
1063 eval { require JSON::XS; JSON::XS->new->utf8 }
1064 || do { require JSON; JSON->new->utf8 }
1065}
1066
517register_write_type json => sub { 1067register_write_type json => sub {
518 my ($self, $ref) = @_; 1068 my ($self, $ref) = @_;
519 1069
520 require JSON; 1070 my $json = $self->{json} ||= json_coder;
521 1071
522 $self->{json} ? $self->{json}->encode ($ref) 1072 $json->encode ($ref)
523 : JSON::encode_json ($ref)
524}; 1073};
525 1074
1075=item storable => $reference
1076
1077Freezes the given reference using L<Storable> and writes it to the
1078handle. Uses the C<nfreeze> format.
1079
1080=cut
1081
1082register_write_type storable => sub {
1083 my ($self, $ref) = @_;
1084
1085 require Storable;
1086
1087 pack "w/a*", Storable::nfreeze ($ref)
1088};
1089
526=back 1090=back
527 1091
528=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args) 1092=item $handle->push_shutdown
529 1093
530This function (not method) lets you add your own types to C<push_write>. 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
531Whenever the given C<type> is used, C<push_write> will invoke the code 1128Whenever the given C<type> is used, C<push_write> will the function with
532reference with the handle object and the remaining arguments. 1129the handle object and the remaining arguments.
533 1130
534The code reference is supposed to return a single octet string that will 1131The function is supposed to return a single octet string that will be
535be appended to the write buffer. 1132appended to the write buffer, so you cna mentally treat this function as a
1133"arguments to on-the-wire-format" converter.
536 1134
537Note that this is a function, and all types registered this way will be 1135Example: implement a custom write type C<join> that joins the remaining
538global, so try to use unique names. 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 }
539 1151
540=cut 1152=cut
541 1153
542############################################################################# 1154#############################################################################
543 1155
552ways, 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
553a queue. 1165a queue.
554 1166
555In 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
556new 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
557enough 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
558or 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>.
559 1173
560In 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
561case, AnyEvent::Handle will call the first queued callback each time new 1175case, AnyEvent::Handle will call the first queued callback each time new
562data 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
563below). 1177done its job (see C<push_read>, below).
564 1178
565This 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
566a chunk of data, and AnyEvent::Handle will execute them in order. 1180a chunk of data, and AnyEvent::Handle will execute them in order.
567 1181
568Example 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
581 # handle xml 1195 # handle xml
582 }); 1196 });
583 }); 1197 });
584 }); 1198 });
585 1199
586Example 2: Implement a client for a protocol that replies either with 1200Example 2: Implement a client for a protocol that replies either with "OK"
587"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
588second 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
589pipeline sending both requests and manipulate the queue as necessary in 1203just pipeline sending both requests and manipulate the queue as necessary
590the callbacks: 1204in the callbacks.
591 1205
592 # 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"
593 $handle->push_write ("request 1\015\012"); 1211 $handle->push_write ("request 1\015\012");
594 1212
595 # 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
596 $handle->push_read (line => sub { 1214 $handle->push_read (line => sub {
597 # if we got an "OK", we have to _prepend_ another line, 1215 # if we got an "OK", we have to _prepend_ another line,
604 ... 1222 ...
605 }); 1223 });
606 } 1224 }
607 }); 1225 });
608 1226
609 # request two 1227 # request two, simply returns 64 octets
610 $handle->push_write ("request 2\015\012"); 1228 $handle->push_write ("request 2\015\012");
611 1229
612 # simply read 64 bytes, always 1230 # simply read 64 bytes, always
613 $handle->push_read (chunk => 64, sub { 1231 $handle->push_read (chunk => 64, sub {
614 my $response = $_[1]; 1232 my $response = $_[1];
620=cut 1238=cut
621 1239
622sub _drain_rbuf { 1240sub _drain_rbuf {
623 my ($self) = @_; 1241 my ($self) = @_;
624 1242
625 if ( 1243 # avoid recursion
626 defined $self->{rbuf_max}
627 && $self->{rbuf_max} < length $self->{rbuf}
628 ) {
629 return $self->_error (&Errno::ENOSPC, 1);
630 }
631
632 return if $self->{in_drain}; 1244 return if $self->{_skip_drain_rbuf};
633 local $self->{in_drain} = 1; 1245 local $self->{_skip_drain_rbuf} = 1;
634 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
635 while (my $len = length $self->{rbuf}) { 1253 my $len = length $self->{rbuf};
636 no strict 'refs'; 1254
637 if (my $cb = shift @{ $self->{_queue} }) { 1255 if (my $cb = shift @{ $self->{_queue} }) {
638 unless ($cb->($self)) { 1256 unless ($cb->($self)) {
1257 # no progress can be made
1258 # (not enough data and no data forthcoming)
1259 $self->_error (Errno::EPIPE, 1), return
639 if ($self->{_eof}) { 1260 if $self->{_eof};
640 # no progress can be made (not enough data and no data forthcoming)
641 return $self->_error (&Errno::EPIPE, 1);
642 }
643 1261
644 unshift @{ $self->{_queue} }, $cb; 1262 unshift @{ $self->{_queue} }, $cb;
645 last; 1263 last;
646 } 1264 }
647 } elsif ($self->{on_read}) { 1265 } elsif ($self->{on_read}) {
1266 last unless $len;
1267
648 $self->{on_read}($self); 1268 $self->{on_read}($self);
649 1269
650 if ( 1270 if (
651 $len == length $self->{rbuf} # if no data has been consumed 1271 $len == length $self->{rbuf} # if no data has been consumed
652 && !@{ $self->{_queue} } # and the queue is still empty 1272 && !@{ $self->{_queue} } # and the queue is still empty
653 && $self->{on_read} # but we still have on_read 1273 && $self->{on_read} # but we still have on_read
654 ) { 1274 ) {
655 # no further data will arrive 1275 # no further data will arrive
656 # so no progress can be made 1276 # so no progress can be made
657 return $self->_error (&Errno::EPIPE, 1) 1277 $self->_error (Errno::EPIPE, 1), return
658 if $self->{_eof}; 1278 if $self->{_eof};
659 1279
660 last; # more data might arrive 1280 last; # more data might arrive
661 } 1281 }
662 } else { 1282 } else {
663 # read side becomes idle 1283 # read side becomes idle
664 delete $self->{_rw}; 1284 delete $self->{_rw} unless $self->{tls};
665 last; 1285 last;
666 } 1286 }
667 } 1287 }
668 1288
1289 if ($self->{_eof}) {
1290 $self->{on_eof}
669 $self->{on_eof}($self) 1291 ? $self->{on_eof}($self)
670 if $self->{_eof} && $self->{on_eof}; 1292 : $self->_error (0, 1, "Unexpected end-of-file");
1293
1294 return;
1295 }
1296
1297 if (
1298 defined $self->{rbuf_max}
1299 && $self->{rbuf_max} < length $self->{rbuf}
1300 ) {
1301 $self->_error (Errno::ENOSPC, 1), return;
1302 }
671 1303
672 # may need to restart read watcher 1304 # may need to restart read watcher
673 unless ($self->{_rw}) { 1305 unless ($self->{_rw}) {
674 $self->start_read 1306 $self->start_read
675 if $self->{on_read} || @{ $self->{_queue} }; 1307 if $self->{on_read} || @{ $self->{_queue} };
680 1312
681This replaces the currently set C<on_read> callback, or clears it (when 1313This replaces the currently set C<on_read> callback, or clears it (when
682the new callback is C<undef>). See the description of C<on_read> in the 1314the new callback is C<undef>). See the description of C<on_read> in the
683constructor. 1315constructor.
684 1316
1317This method may invoke callbacks (and therefore the handle might be
1318destroyed after it returns).
1319
685=cut 1320=cut
686 1321
687sub on_read { 1322sub on_read {
688 my ($self, $cb) = @_; 1323 my ($self, $cb) = @_;
689 1324
690 $self->{on_read} = $cb; 1325 $self->{on_read} = $cb;
1326 $self->_drain_rbuf if $cb;
691} 1327}
692 1328
693=item $handle->rbuf 1329=item $handle->rbuf
694 1330
695Returns 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).
696 1334
697You 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)
698you 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.
699 1338
700NOTE: 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>
701C<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
702automatically 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.
703 1343
704=cut 1344=cut
705 1345
706sub rbuf : lvalue { 1346sub rbuf : lvalue {
707 $_[0]{rbuf} 1347 $_[0]{rbuf}
724 1364
725If 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
726interested 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
727true, it will be removed from the queue. 1367true, it will be removed from the queue.
728 1368
1369These methods may invoke callbacks (and therefore the handle might be
1370destroyed after it returns).
1371
729=cut 1372=cut
730 1373
731our %RH; 1374our %RH;
732 1375
733sub register_read_type($$) { 1376sub register_read_type($$) {
739 my $cb = pop; 1382 my $cb = pop;
740 1383
741 if (@_) { 1384 if (@_) {
742 my $type = shift; 1385 my $type = shift;
743 1386
1387 $cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
744 $cb = ($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")
745 ->($self, $cb, @_); 1389 ->($self, $cb, @_);
746 } 1390 }
747 1391
748 push @{ $self->{_queue} }, $cb; 1392 push @{ $self->{_queue} }, $cb;
749 $self->_drain_rbuf; 1393 $self->_drain_rbuf;
754 my $cb = pop; 1398 my $cb = pop;
755 1399
756 if (@_) { 1400 if (@_) {
757 my $type = shift; 1401 my $type = shift;
758 1402
1403 $cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
759 $cb = ($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")
760 ->($self, $cb, @_); 1405 ->($self, $cb, @_);
761 } 1406 }
762
763 1407
764 unshift @{ $self->{_queue} }, $cb; 1408 unshift @{ $self->{_queue} }, $cb;
765 $self->_drain_rbuf; 1409 $self->_drain_rbuf;
766} 1410}
767 1411
769 1413
770=item $handle->unshift_read (type => @args, $cb) 1414=item $handle->unshift_read (type => @args, $cb)
771 1415
772Instead 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
773between a number of predefined parsing formats, for chunks of data, lines 1417between a number of predefined parsing formats, for chunks of data, lines
774etc. 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).
775 1421
776Predefined 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
777drop by and tell us): 1423drop by and tell us):
778 1424
779=over 4 1425=over 4
800 $cb->($_[0], substr $_[0]{rbuf}, 0, $len, ""); 1446 $cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
801 1 1447 1
802 } 1448 }
803}; 1449};
804 1450
805# compatibility with older API
806sub push_read_chunk {
807 $_[0]->push_read (chunk => $_[1], $_[2]);
808}
809
810sub unshift_read_chunk {
811 $_[0]->unshift_read (chunk => $_[1], $_[2]);
812}
813
814=item line => [$eol, ]$cb->($handle, $line, $eol) 1451=item line => [$eol, ]$cb->($handle, $line, $eol)
815 1452
816The callback will be called only once a full line (including the end of 1453The callback will be called only once a full line (including the end of
817line marker, C<$eol>) has been read. This line (excluding the end of line 1454line marker, C<$eol>) has been read. This line (excluding the end of line
818marker) will be passed to the callback as second argument (C<$line>), and 1455marker) will be passed to the callback as second argument (C<$line>), and
833=cut 1470=cut
834 1471
835register_read_type line => sub { 1472register_read_type line => sub {
836 my ($self, $cb, $eol) = @_; 1473 my ($self, $cb, $eol) = @_;
837 1474
838 $eol = qr|(\015?\012)| if @_ < 3; 1475 if (@_ < 3) {
839 $eol = quotemeta $eol unless ref $eol; 1476 # this is more than twice as fast as the generic code below
840 $eol = qr|^(.*?)($eol)|s;
841
842 sub { 1477 sub {
843 $_[0]{rbuf} =~ s/$eol// or return; 1478 $_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
844 1479
845 $cb->($_[0], $1, $2); 1480 $cb->($_[0], $1, $2);
846 1
847 }
848};
849
850# compatibility with older API
851sub push_read_line {
852 my $self = shift;
853 $self->push_read (line => @_);
854}
855
856sub unshift_read_line {
857 my $self = shift;
858 $self->unshift_read (line => @_);
859}
860
861=item netstring => $cb->($handle, $string)
862
863A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
864
865Throws an error with C<$!> set to EBADMSG on format violations.
866
867=cut
868
869register_read_type netstring => sub {
870 my ($self, $cb) = @_;
871
872 sub {
873 unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
874 if ($_[0]{rbuf} =~ /[^0-9]/) {
875 $self->_error (&Errno::EBADMSG);
876 } 1481 1
877 return;
878 } 1482 }
1483 } else {
1484 $eol = quotemeta $eol unless ref $eol;
1485 $eol = qr|^(.*?)($eol)|s;
879 1486
880 my $len = $1; 1487 sub {
1488 $_[0]{rbuf} =~ s/$eol// or return;
881 1489
882 $self->unshift_read (chunk => $len, sub { 1490 $cb->($_[0], $1, $2);
883 my $string = $_[1];
884 $_[0]->unshift_read (chunk => 1, sub {
885 if ($_[1] eq ",") {
886 $cb->($_[0], $string);
887 } else {
888 $self->_error (&Errno::EBADMSG);
889 }
890 }); 1491 1
891 }); 1492 }
892
893 1
894 } 1493 }
895}; 1494};
896 1495
897=item regex => $accept[, $reject[, $skip], $cb->($handle, $data) 1496=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
898 1497
918the receive buffer when neither C<$accept> nor C<$reject> match, 1517the receive buffer when neither C<$accept> nor C<$reject> match,
919and everything preceding and including the match will be accepted 1518and everything preceding and including the match will be accepted
920unconditionally. This is useful to skip large amounts of data that you 1519unconditionally. This is useful to skip large amounts of data that you
921know cannot be matched, so that the C<$accept> or C<$reject> regex do not 1520know cannot be matched, so that the C<$accept> or C<$reject> regex do not
922have to start matching from the beginning. This is purely an optimisation 1521have to start matching from the beginning. This is purely an optimisation
923and 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.
924 1523
925Example: 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
926expect 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
927a 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
928it 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
929required for the accept regex. 1528required for the accept regex.
930 1529
931 $handle->push_read (regex => 1530 $handle->push_read (regex =>
950 return 1; 1549 return 1;
951 } 1550 }
952 1551
953 # reject 1552 # reject
954 if ($reject && $$rbuf =~ $reject) { 1553 if ($reject && $$rbuf =~ $reject) {
955 $self->_error (&Errno::EBADMSG); 1554 $self->_error (Errno::EBADMSG);
956 } 1555 }
957 1556
958 # skip 1557 # skip
959 if ($skip && $$rbuf =~ $skip) { 1558 if ($skip && $$rbuf =~ $skip) {
960 $data .= substr $$rbuf, 0, $+[0], ""; 1559 $data .= substr $$rbuf, 0, $+[0], "";
962 1561
963 () 1562 ()
964 } 1563 }
965}; 1564};
966 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
967=item json => $cb->($handle, $hash_or_arrayref) 1648=item json => $cb->($handle, $hash_or_arrayref)
968 1649
969Reads a JSON object or array, decodes it and passes it to the callback. 1650Reads a JSON object or array, decodes it and passes it to the
1651callback. When a parse error occurs, an C<EBADMSG> error will be raised.
970 1652
971If a C<json> object was passed to the constructor, then that will be used 1653If a C<json> object was passed to the constructor, then that will be used
972for the final decode, otherwise it will create a JSON coder expecting UTF-8. 1654for the final decode, otherwise it will create a JSON coder expecting UTF-8.
973 1655
974This read type uses the incremental parser available with JSON version 1656This read type uses the incremental parser available with JSON version
981the C<json> write type description, above, for an actual example. 1663the C<json> write type description, above, for an actual example.
982 1664
983=cut 1665=cut
984 1666
985register_read_type json => sub { 1667register_read_type json => sub {
986 my ($self, $cb, $accept, $reject, $skip) = @_; 1668 my ($self, $cb) = @_;
987 1669
988 require JSON; 1670 my $json = $self->{json} ||= json_coder;
989 1671
990 my $data; 1672 my $data;
991 my $rbuf = \$self->{rbuf}; 1673 my $rbuf = \$self->{rbuf};
992 1674
993 my $json = $self->{json} ||= JSON->new->utf8;
994
995 sub { 1675 sub {
996 my $ref = $json->incr_parse ($self->{rbuf}); 1676 my $ref = eval { $json->incr_parse ($self->{rbuf}) };
997 1677
998 if ($ref) { 1678 if ($ref) {
999 $self->{rbuf} = $json->incr_text; 1679 $self->{rbuf} = $json->incr_text;
1000 $json->incr_text = ""; 1680 $json->incr_text = "";
1001 $cb->($self, $ref); 1681 $cb->($self, $ref);
1002 1682
1003 1 1683 1
1684 } elsif ($@) {
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 ()
1004 } else { 1694 } else {
1005 $self->{rbuf} = ""; 1695 $self->{rbuf} = "";
1696
1006 () 1697 ()
1007 } 1698 }
1008 } 1699 }
1009}; 1700};
1010 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
1011=back 1747=back
1012 1748
1013=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args) 1749=item custom read types - Package::anyevent_read_type $handle, $cb, @args
1014 1750
1015This function (not method) lets you add your own types to C<push_read>. 1751Instead of one of the predefined types, you can also specify the name
1752of a package. AnyEvent will try to load the package and then expects to
1753find a function named C<anyevent_read_type> inside. If it isn't found, it
1754progressively tries to load the parent package until it either finds the
1755function (good) or runs out of packages (bad).
1016 1756
1017Whenever the given C<type> is used, C<push_read> will invoke the code 1757Whenever this type is used, C<push_read> will invoke the function with the
1018reference with the handle object, the callback and the remaining 1758handle object, the original callback and the remaining arguments.
1019arguments.
1020 1759
1021The code reference is supposed to return a callback (usually a closure) 1760The function is supposed to return a callback (usually a closure) that
1022that works as a plain read callback (see C<< ->push_read ($cb) >>). 1761works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
1762mentally treat the function as a "configurable read type to read callback"
1763converter.
1023 1764
1024It should invoke the passed callback when it is done reading (remember to 1765It should invoke the original callback when it is done reading (remember
1025pass C<$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).
1026 1768
1027Note that this is a function, and all types registered this way will be
1028global, so try to use unique names.
1029
1030For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>, 1769For examples, see the source of this module (F<perldoc -m
1031search for C<register_read_type>)). 1770AnyEvent::Handle>, search for C<register_read_type>)).
1032 1771
1033=item $handle->stop_read 1772=item $handle->stop_read
1034 1773
1035=item $handle->start_read 1774=item $handle->start_read
1036 1775
1037In rare cases you actually do not want to read anything from the 1776In rare cases you actually do not want to read anything from the
1038socket. In this case you can call C<stop_read>. Neither C<on_read> no 1777socket. In this case you can call C<stop_read>. Neither C<on_read> nor
1039any queued callbacks will be executed then. To start reading again, call 1778any queued callbacks will be executed then. To start reading again, call
1040C<start_read>. 1779C<start_read>.
1041 1780
1042Note that AnyEvent::Handle will automatically C<start_read> for you when 1781Note that AnyEvent::Handle will automatically C<start_read> for you when
1043you change the C<on_read> callback or push/unshift a read callback, and it 1782you change the C<on_read> callback or push/unshift a read callback, and it
1044will automatically C<stop_read> for you when neither C<on_read> is set nor 1783will automatically C<stop_read> for you when neither C<on_read> is set nor
1045there are any read requests in the queue. 1784there are any read requests in the queue.
1046 1785
1786In older versions of this module (<= 5.3), these methods had no effect,
1787as TLS does not support half-duplex connections. In current versions they
1788work as expected, as this behaviour is required to avoid certain resource
1789attacks, where the program would be forced to read (and buffer) arbitrary
1790amounts of data before being able to send some data. The drawback is that
1791some readings of the the SSL/TLS specifications basically require this
1792attack to be working, as SSL/TLS implementations might stall sending data
1793during a rehandshake.
1794
1795As a guideline, during the initial handshake, you should not stop reading,
1796and as a client, it might cause problems, depending on your applciation.
1797
1047=cut 1798=cut
1048 1799
1049sub stop_read { 1800sub stop_read {
1050 my ($self) = @_; 1801 my ($self) = @_;
1051 1802
1053} 1804}
1054 1805
1055sub start_read { 1806sub start_read {
1056 my ($self) = @_; 1807 my ($self) = @_;
1057 1808
1058 unless ($self->{_rw} || $self->{_eof}) { 1809 unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
1059 Scalar::Util::weaken $self; 1810 Scalar::Util::weaken $self;
1060 1811
1061 $self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub { 1812 $self->{_rw} = AE::io $self->{fh}, 0, sub {
1062 my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf}; 1813 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1063 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf; 1814 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
1064 1815
1065 if ($len > 0) { 1816 if ($len > 0) {
1066 $self->{_activity} = AnyEvent->now; 1817 $self->{_activity} = $self->{_ractivity} = AE::now;
1067 1818
1068 $self->{filter_r} 1819 if ($self->{tls}) {
1069 ? $self->{filter_r}($self, $rbuf) 1820 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1821
1822 &_dotls ($self);
1823 } else {
1070 : $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 }
1071 1832
1072 } elsif (defined $len) { 1833 } elsif (defined $len) {
1073 delete $self->{_rw}; 1834 delete $self->{_rw};
1074 $self->{_eof} = 1; 1835 $self->{_eof} = 1;
1075 $self->_drain_rbuf; 1836 $self->_drain_rbuf;
1076 1837
1077 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) { 1838 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
1078 return $self->_error ($!, 1); 1839 return $self->_error ($!, 1);
1079 } 1840 }
1080 }); 1841 };
1081 } 1842 }
1082} 1843}
1083 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, $err);
1865 }
1866}
1867
1868# poll the write BIO and send the data if applicable
1869# also decode read data if possible
1870# this is basiclaly our TLS state machine
1871# more efficient implementations are possible with openssl,
1872# but not with the buggy and incomplete Net::SSLeay.
1084sub _dotls { 1873sub _dotls {
1085 my ($self) = @_; 1874 my ($self) = @_;
1086 1875
1087 my $buf; 1876 my $tmp;
1088 1877
1089 if (length $self->{_tls_wbuf}) { 1878 if (length $self->{_tls_wbuf}) {
1090 while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) { 1879 while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
1091 substr $self->{_tls_wbuf}, 0, $len, ""; 1880 substr $self->{_tls_wbuf}, 0, $tmp, "";
1092 } 1881 }
1093 }
1094 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 || $!);
1914
1095 if (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) { 1915 while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1096 $self->{wbuf} .= $buf; 1916 $self->{wbuf} .= $tmp;
1097 $self->_drain_wbuf; 1917 $self->_drain_wbuf;
1918 $self->{tls} or return; # tls session might have gone away in callback
1098 } 1919 }
1099 1920
1100 while (defined ($buf = Net::SSLeay::read ($self->{tls}))) { 1921 $self->{_on_starttls}
1101 if (length $buf) { 1922 and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
1102 $self->{rbuf} .= $buf; 1923 and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
1103 $self->_drain_rbuf;
1104 } else {
1105 # let's treat SSL-eof as we treat normal EOF
1106 $self->{_eof} = 1;
1107 $self->_shutdown;
1108 return;
1109 }
1110 }
1111
1112 my $err = Net::SSLeay::get_error ($self->{tls}, -1);
1113
1114 if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
1115 if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
1116 return $self->_error ($!, 1);
1117 } elsif ($err == Net::SSLeay::ERROR_SSL ()) {
1118 return $self->_error (&Errno::EIO, 1);
1119 }
1120
1121 # all others are fine for our purposes
1122 }
1123} 1924}
1124 1925
1125=item $handle->starttls ($tls[, $tls_ctx]) 1926=item $handle->starttls ($tls[, $tls_ctx])
1126 1927
1127Instead of starting TLS negotiation immediately when the AnyEvent::Handle 1928Instead of starting TLS negotiation immediately when the AnyEvent::Handle
1128object 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
1129C<starttls>. 1930C<starttls>.
1130 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
1131The 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
1132C<"connect">, C<"accept"> or an existing Net::SSLeay object). 1937C<"connect">, C<"accept"> or an existing Net::SSLeay object).
1133 1938
1134The 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
1135used 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.
1136 1943
1137The 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
1138call and can be used or changed to your liking. Note that the handshake 1945context in C<< $handle->{tls_ctx} >> after this call and can be used or
1139might have already started when this function returns. 1946changed to your liking. Note that the handshake might have already started
1947when this function returns.
1140 1948
1949Due to bugs in OpenSSL, it might or might not be possible to do multiple
1950handshakes on the same stream. It is best to not attempt to use the
1951stream after stopping TLS.
1952
1953This method may invoke callbacks (and therefore the handle might be
1954destroyed after it returns).
1955
1141=cut 1956=cut
1957
1958our %TLS_CACHE; #TODO not yet documented, should we?
1142 1959
1143sub starttls { 1960sub starttls {
1144 my ($self, $ssl, $ctx) = @_; 1961 my ($self, $tls, $ctx) = @_;
1145 1962
1146 $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 $self->{tls};
1147 1965
1148 if ($ssl eq "accept") { 1966 $self->{tls} = $tls;
1149 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1967 $self->{tls_ctx} = $ctx if @_ > 2;
1150 Net::SSLeay::set_accept_state ($ssl); 1968
1151 } elsif ($ssl eq "connect") { 1969 return unless $self->{fh};
1152 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1970
1153 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 }
1154 } 1991
1155 1992 $self->{tls_ctx} = $ctx || TLS_CTX ();
1156 $self->{tls} = $ssl; 1993 $self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
1157 1994
1158 # basically, this is deep magic (because SSL_read should have the same issues) 1995 # basically, this is deep magic (because SSL_read should have the same issues)
1159 # but the openssl maintainers basically said: "trust us, it just works". 1996 # but the openssl maintainers basically said: "trust us, it just works".
1160 # (unfortunately, we have to hardcode constants because the abysmally misdesigned 1997 # (unfortunately, we have to hardcode constants because the abysmally misdesigned
1161 # and mismaintained ssleay-module doesn't even offer them). 1998 # and mismaintained ssleay-module doesn't even offer them).
1162 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html 1999 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
2000 #
2001 # in short: this is a mess.
2002 #
2003 # note that we do not try to keep the length constant between writes as we are required to do.
2004 # we assume that most (but not all) of this insanity only applies to non-blocking cases,
2005 # and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
2006 # have identity issues in that area.
1163 Net::SSLeay::CTX_set_mode ($self->{tls}, 2007# Net::SSLeay::CTX_set_mode ($ssl,
1164 (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1) 2008# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
1165 | (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);
1166 2011
1167 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 2012 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1168 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 2013 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1169 2014
2015 Net::SSLeay::BIO_write ($self->{_rbio}, delete $self->{rbuf});
2016
1170 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio}); 2017 Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
1171 2018
1172 $self->{filter_w} = sub { 2019 $self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
1173 $_[0]{_tls_wbuf} .= ${$_[1]}; 2020 if $self->{on_starttls};
1174 &_dotls; 2021
1175 }; 2022 &_dotls; # need to trigger the initial handshake
1176 $self->{filter_r} = sub { 2023 $self->start_read; # make sure we actually do read
1177 Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
1178 &_dotls;
1179 };
1180} 2024}
1181 2025
1182=item $handle->stoptls 2026=item $handle->stoptls
1183 2027
1184Destroys the SSL connection, if any. Partial read or write data will be 2028Shuts down the SSL connection - this makes a proper EOF handshake by
1185lost. 2029sending a close notify to the other side, but since OpenSSL doesn't
2030support non-blocking shut downs, it is not guaranteed that you can re-use
2031the stream afterwards.
2032
2033This method may invoke callbacks (and therefore the handle might be
2034destroyed after it returns).
1186 2035
1187=cut 2036=cut
1188 2037
1189sub stoptls { 2038sub stoptls {
1190 my ($self) = @_; 2039 my ($self) = @_;
1191 2040
1192 Net::SSLeay::free (delete $self->{tls}) if $self->{tls}; 2041 if ($self->{tls} && $self->{fh}) {
2042 Net::SSLeay::shutdown ($self->{tls});
1193 2043
1194 delete $self->{_rbio}; 2044 &_dotls;
1195 delete $self->{_wbio}; 2045
1196 delete $self->{_tls_wbuf}; 2046# # we don't give a shit. no, we do, but we can't. no...#d#
1197 delete $self->{filter_r}; 2047# # we, we... have to use openssl :/#d#
1198 delete $self->{filter_w}; 2048# &_freetls;#d#
2049 }
1199} 2050}
2051
2052sub _freetls {
2053 my ($self) = @_;
2054
2055 return unless $self->{tls};
2056
2057 $self->{tls_ctx}->_put_session (delete $self->{tls})
2058 if $self->{tls} > 0;
2059
2060 delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
2061}
2062
2063=item $handle->resettls
2064
2065This rarely-used method simply resets and TLS state on the handle, usually
2066causing data loss.
2067
2068One case where it may be useful is when you want to skip over the data in
2069the stream but you are not interested in interpreting it, so data loss is
2070no concern.
2071
2072=cut
2073
2074*resettls = \&_freetls;
1200 2075
1201sub DESTROY { 2076sub DESTROY {
1202 my $self = shift; 2077 my ($self) = @_;
1203 2078
1204 $self->stoptls; 2079 &_freetls;
2080
2081 my $linger = exists $self->{linger} ? $self->{linger} : 3600;
2082
2083 if ($linger && length $self->{wbuf} && $self->{fh}) {
2084 my $fh = delete $self->{fh};
2085 my $wbuf = delete $self->{wbuf};
2086
2087 my @linger;
2088
2089 push @linger, AE::io $fh, 1, sub {
2090 my $len = syswrite $fh, $wbuf, length $wbuf;
2091
2092 if ($len > 0) {
2093 substr $wbuf, 0, $len, "";
2094 } elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
2095 @linger = (); # end
2096 }
2097 };
2098 push @linger, AE::timer $linger, 0, sub {
2099 @linger = ();
2100 };
2101 }
1205} 2102}
2103
2104=item $handle->destroy
2105
2106Shuts down the handle object as much as possible - this call ensures that
2107no further callbacks will be invoked and as many resources as possible
2108will be freed. Any method you will call on the handle object after
2109destroying it in this way will be silently ignored (and it will return the
2110empty list).
2111
2112Normally, you can just "forget" any references to an AnyEvent::Handle
2113object and it will simply shut down. This works in fatal error and EOF
2114callbacks, as well as code outside. It does I<NOT> work in a read or write
2115callback, so when you want to destroy the AnyEvent::Handle object from
2116within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
2117that case.
2118
2119Destroying the handle object in this way has the advantage that callbacks
2120will be removed as well, so if those are the only reference holders (as
2121is common), then one doesn't need to do anything special to break any
2122reference cycles.
2123
2124The handle might still linger in the background and write out remaining
2125data, as specified by the C<linger> option, however.
2126
2127=cut
2128
2129sub destroy {
2130 my ($self) = @_;
2131
2132 $self->DESTROY;
2133 %$self = ();
2134 bless $self, "AnyEvent::Handle::destroyed";
2135}
2136
2137sub AnyEvent::Handle::destroyed::AUTOLOAD {
2138 #nop
2139}
2140
2141=item $handle->destroyed
2142
2143Returns false as long as the handle hasn't been destroyed by a call to C<<
2144->destroy >>, true otherwise.
2145
2146Can be useful to decide whether the handle is still valid after some
2147callback possibly destroyed the handle. For example, C<< ->push_write >>,
2148C<< ->starttls >> and other methods can call user callbacks, which in turn
2149can destroy the handle, so work can be avoided by checking sometimes:
2150
2151 $hdl->starttls ("accept");
2152 return if $hdl->destroyed;
2153 $hdl->push_write (...
2154
2155Note that the call to C<push_write> will silently be ignored if the handle
2156has been destroyed, so often you can just ignore the possibility of the
2157handle being destroyed.
2158
2159=cut
2160
2161sub destroyed { 0 }
2162sub AnyEvent::Handle::destroyed::destroyed { 1 }
1206 2163
1207=item AnyEvent::Handle::TLS_CTX 2164=item AnyEvent::Handle::TLS_CTX
1208 2165
1209This function creates and returns the Net::SSLeay::CTX object used by 2166This function creates and returns the AnyEvent::TLS object used by default
1210default for TLS mode. 2167for TLS mode.
1211 2168
1212The context is created like this: 2169The context is created by calling L<AnyEvent::TLS> without any arguments.
1213
1214 Net::SSLeay::load_error_strings;
1215 Net::SSLeay::SSLeay_add_ssl_algorithms;
1216 Net::SSLeay::randomize;
1217
1218 my $CTX = Net::SSLeay::CTX_new;
1219
1220 Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
1221 2170
1222=cut 2171=cut
1223 2172
1224our $TLS_CTX; 2173our $TLS_CTX;
1225 2174
1226sub TLS_CTX() { 2175sub TLS_CTX() {
1227 $TLS_CTX || do { 2176 $TLS_CTX ||= do {
1228 require Net::SSLeay; 2177 require AnyEvent::TLS;
1229 2178
1230 Net::SSLeay::load_error_strings (); 2179 new AnyEvent::TLS
1231 Net::SSLeay::SSLeay_add_ssl_algorithms ();
1232 Net::SSLeay::randomize ();
1233
1234 $TLS_CTX = Net::SSLeay::CTX_new ();
1235
1236 Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
1237
1238 $TLS_CTX
1239 } 2180 }
1240} 2181}
1241 2182
1242=back 2183=back
2184
2185
2186=head1 NONFREQUENTLY ASKED QUESTIONS
2187
2188=over 4
2189
2190=item I C<undef> the AnyEvent::Handle reference inside my callback and
2191still get further invocations!
2192
2193That's because AnyEvent::Handle keeps a reference to itself when handling
2194read or write callbacks.
2195
2196It is only safe to "forget" the reference inside EOF or error callbacks,
2197from within all other callbacks, you need to explicitly call the C<<
2198->destroy >> method.
2199
2200=item Why is my C<on_eof> callback never called?
2201
2202Probably because your C<on_error> callback is being called instead: When
2203you have outstanding requests in your read queue, then an EOF is
2204considered an error as you clearly expected some data.
2205
2206To avoid this, make sure you have an empty read queue whenever your handle
2207is supposed to be "idle" (i.e. connection closes are O.K.). You cna set
2208an C<on_read> handler that simply pushes the first read requests in the
2209queue.
2210
2211See also the next question, which explains this in a bit more detail.
2212
2213=item How can I serve requests in a loop?
2214
2215Most protocols consist of some setup phase (authentication for example)
2216followed by a request handling phase, where the server waits for requests
2217and handles them, in a loop.
2218
2219There are two important variants: The first (traditional, better) variant
2220handles requests until the server gets some QUIT command, causing it to
2221close the connection first (highly desirable for a busy TCP server). A
2222client dropping the connection is an error, which means this variant can
2223detect an unexpected detection close.
2224
2225To handle this case, always make sure you have a on-empty read queue, by
2226pushing the "read request start" handler on it:
2227
2228 # we assume a request starts with a single line
2229 my @start_request; @start_request = (line => sub {
2230 my ($hdl, $line) = @_;
2231
2232 ... handle request
2233
2234 # push next request read, possibly from a nested callback
2235 $hdl->push_read (@start_request);
2236 });
2237
2238 # auth done, now go into request handling loop
2239 # now push the first @start_request
2240 $hdl->push_read (@start_request);
2241
2242By always having an outstanding C<push_read>, the handle always expects
2243some data and raises the C<EPIPE> error when the connction is dropped
2244unexpectedly.
2245
2246The second variant is a protocol where the client can drop the connection
2247at any time. For TCP, this means that the server machine may run out of
2248sockets easier, and in general, it means you cnanot distinguish a protocl
2249failure/client crash from a normal connection close. Nevertheless, these
2250kinds of protocols are common (and sometimes even the best solution to the
2251problem).
2252
2253Having an outstanding read request at all times is possible if you ignore
2254C<EPIPE> errors, but this doesn't help with when the client drops the
2255connection during a request, which would still be an error.
2256
2257A better solution is to push the initial request read in an C<on_read>
2258callback. This avoids an error, as when the server doesn't expect data
2259(i.e. is idly waiting for the next request, an EOF will not raise an
2260error, but simply result in an C<on_eof> callback. It is also a bit slower
2261and simpler:
2262
2263 # auth done, now go into request handling loop
2264 $hdl->on_read (sub {
2265 my ($hdl) = @_;
2266
2267 # called each time we receive data but the read queue is empty
2268 # simply start read the request
2269
2270 $hdl->push_read (line => sub {
2271 my ($hdl, $line) = @_;
2272
2273 ... handle request
2274
2275 # do nothing special when the request has been handled, just
2276 # let the request queue go empty.
2277 });
2278 });
2279
2280=item I get different callback invocations in TLS mode/Why can't I pause
2281reading?
2282
2283Unlike, say, TCP, TLS connections do not consist of two independent
2284communication channels, one for each direction. Or put differently, the
2285read and write directions are not independent of each other: you cannot
2286write data unless you are also prepared to read, and vice versa.
2287
2288This means that, in TLS mode, you might get C<on_error> or C<on_eof>
2289callback invocations when you are not expecting any read data - the reason
2290is that AnyEvent::Handle always reads in TLS mode.
2291
2292During the connection, you have to make sure that you always have a
2293non-empty read-queue, or an C<on_read> watcher. At the end of the
2294connection (or when you no longer want to use it) you can call the
2295C<destroy> method.
2296
2297=item How do I read data until the other side closes the connection?
2298
2299If you just want to read your data into a perl scalar, the easiest way
2300to achieve this is by setting an C<on_read> callback that does nothing,
2301clearing the C<on_eof> callback and in the C<on_error> callback, the data
2302will be in C<$_[0]{rbuf}>:
2303
2304 $handle->on_read (sub { });
2305 $handle->on_eof (undef);
2306 $handle->on_error (sub {
2307 my $data = delete $_[0]{rbuf};
2308 });
2309
2310The reason to use C<on_error> is that TCP connections, due to latencies
2311and packets loss, might get closed quite violently with an error, when in
2312fact all data has been received.
2313
2314It is usually better to use acknowledgements when transferring data,
2315to make sure the other side hasn't just died and you got the data
2316intact. This is also one reason why so many internet protocols have an
2317explicit QUIT command.
2318
2319=item I don't want to destroy the handle too early - how do I wait until
2320all data has been written?
2321
2322After writing your last bits of data, set the C<on_drain> callback
2323and destroy the handle in there - with the default setting of
2324C<low_water_mark> this will be called precisely when all data has been
2325written to the socket:
2326
2327 $handle->push_write (...);
2328 $handle->on_drain (sub {
2329 warn "all data submitted to the kernel\n";
2330 undef $handle;
2331 });
2332
2333If you just want to queue some data and then signal EOF to the other side,
2334consider using C<< ->push_shutdown >> instead.
2335
2336=item I want to contact a TLS/SSL server, I don't care about security.
2337
2338If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
2339connect to it and then create the AnyEvent::Handle with the C<tls>
2340parameter:
2341
2342 tcp_connect $host, $port, sub {
2343 my ($fh) = @_;
2344
2345 my $handle = new AnyEvent::Handle
2346 fh => $fh,
2347 tls => "connect",
2348 on_error => sub { ... };
2349
2350 $handle->push_write (...);
2351 };
2352
2353=item I want to contact a TLS/SSL server, I do care about security.
2354
2355Then you should additionally enable certificate verification, including
2356peername verification, if the protocol you use supports it (see
2357L<AnyEvent::TLS>, C<verify_peername>).
2358
2359E.g. for HTTPS:
2360
2361 tcp_connect $host, $port, sub {
2362 my ($fh) = @_;
2363
2364 my $handle = new AnyEvent::Handle
2365 fh => $fh,
2366 peername => $host,
2367 tls => "connect",
2368 tls_ctx => { verify => 1, verify_peername => "https" },
2369 ...
2370
2371Note that you must specify the hostname you connected to (or whatever
2372"peername" the protocol needs) as the C<peername> argument, otherwise no
2373peername verification will be done.
2374
2375The above will use the system-dependent default set of trusted CA
2376certificates. If you want to check against a specific CA, add the
2377C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
2378
2379 tls_ctx => {
2380 verify => 1,
2381 verify_peername => "https",
2382 ca_file => "my-ca-cert.pem",
2383 },
2384
2385=item I want to create a TLS/SSL server, how do I do that?
2386
2387Well, you first need to get a server certificate and key. You have
2388three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
2389self-signed certificate (cheap. check the search engine of your choice,
2390there are many tutorials on the net) or c) make your own CA (tinyca2 is a
2391nice program for that purpose).
2392
2393Then create a file with your private key (in PEM format, see
2394L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
2395file should then look like this:
2396
2397 -----BEGIN RSA PRIVATE KEY-----
2398 ...header data
2399 ... lots of base64'y-stuff
2400 -----END RSA PRIVATE KEY-----
2401
2402 -----BEGIN CERTIFICATE-----
2403 ... lots of base64'y-stuff
2404 -----END CERTIFICATE-----
2405
2406The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
2407specify this file as C<cert_file>:
2408
2409 tcp_server undef, $port, sub {
2410 my ($fh) = @_;
2411
2412 my $handle = new AnyEvent::Handle
2413 fh => $fh,
2414 tls => "accept",
2415 tls_ctx => { cert_file => "my-server-keycert.pem" },
2416 ...
2417
2418When you have intermediate CA certificates that your clients might not
2419know about, just append them to the C<cert_file>.
2420
2421=back
2422
1243 2423
1244=head1 SUBCLASSING AnyEvent::Handle 2424=head1 SUBCLASSING AnyEvent::Handle
1245 2425
1246In many cases, you might want to subclass AnyEvent::Handle. 2426In many cases, you might want to subclass AnyEvent::Handle.
1247 2427
1251=over 4 2431=over 4
1252 2432
1253=item * all constructor arguments become object members. 2433=item * all constructor arguments become object members.
1254 2434
1255At least initially, when you pass a C<tls>-argument to the constructor it 2435At least initially, when you pass a C<tls>-argument to the constructor it
1256will end up in C<< $handle->{tls} >>. Those members might be changes or 2436will end up in C<< $handle->{tls} >>. Those members might be changed or
1257mutated later on (for example C<tls> will hold the TLS connection object). 2437mutated later on (for example C<tls> will hold the TLS connection object).
1258 2438
1259=item * other object member names are prefixed with an C<_>. 2439=item * other object member names are prefixed with an C<_>.
1260 2440
1261All object members not explicitly documented (internal use) are prefixed 2441All object members not explicitly documented (internal use) are prefixed
1264 2444
1265=item * all members not documented here and not prefixed with an underscore 2445=item * all members not documented here and not prefixed with an underscore
1266are free to use in subclasses. 2446are free to use in subclasses.
1267 2447
1268Of course, new versions of AnyEvent::Handle may introduce more "public" 2448Of course, new versions of AnyEvent::Handle may introduce more "public"
1269member variables, but thats just life, at least it is documented. 2449member variables, but that's just life. At least it is documented.
1270 2450
1271=back 2451=back
1272 2452
1273=head1 AUTHOR 2453=head1 AUTHOR
1274 2454

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