[ViewVC] Diff of: cvs/AnyEvent-MP/MP.pm

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs.
Revision 1.52 by root, Fri Aug 14 15:13:20 2009 UTC

…		…
9	$NODE # contains this node's noderef	9	$NODE # contains this node's noderef
10	NODE # returns this node's noderef	10	NODE # returns this node's noderef
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
13	$SELF # receiving/own port id in rcv callbacks	13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# initialise the node so it can send/receive messages
		16	initialise_node; # -OR-
		17	initialise_node "localhost:4040"; # -OR-
		18	initialise_node "slave/", "localhost:4040"
14		19
15	# ports are message endpoints	20	# ports are message endpoints
16		21
17	# sending messages	22	# sending messages
18	snd $port, type => data...;	23	snd $port, type => data...;
19	snd $port, @msg;	24	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	25	snd @msg_with_first_element_being_a_port;
21		26
22	# miniports	27	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	28	my $somple_port = port { my @msg = @_; 0 };
24		29
25	# full ports	30	# creating/using ports, tagged message matching
26	my $port = port;	31	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	32	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	33	rcv $port, pong => sub { warn "pong received\n"; 0 };
30		34
31	# remote ports	35	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	36	my $port = spawn $node, $initfunc, @initdata;
33
34	# more, smarter, matches (_any_ is exported by this module)
35	rcv $port, [child_died => $pid] => sub { ...
36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
37		37
38	# monitoring	38	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	39	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	40	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	41	mon $port, $otherport, @msg # send message on death
42		42
		43	=head1 CURRENT STATUS
		44
		45	AnyEvent::MP - stable API, should work
		46	AnyEvent::MP::Intro - outdated
		47	AnyEvent::MP::Kernel - WIP
		48	AnyEvent::MP::Transport - mostly stable
		49
		50	stay tuned.
		51
43	=head1 DESCRIPTION	52	=head1 DESCRIPTION
44		53
45	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
46		55
47	Despite its simplicity, you can securely message other processes running	56	Despite its simplicity, you can securely message other processes running
…		…
50	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	59	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
51	manual page.	60	manual page.
52		61
53	At the moment, this module family is severly broken and underdocumented,	62	At the moment, this module family is severly broken and underdocumented,
54	so do not use. This was uploaded mainly to reserve the CPAN namespace -	63	so do not use. This was uploaded mainly to reserve the CPAN namespace -
55	stay tuned! The basic API should be finished, however.	64	stay tuned!
56		65
57	=head1 CONCEPTS	66	=head1 CONCEPTS
58		67
59	=over 4	68	=over 4
60		69
…		…
105		114
106	=cut	115	=cut
107		116
108	package AnyEvent::MP;	117	package AnyEvent::MP;
109		118
110	use AnyEvent::MP::Base;	119	use AnyEvent::MP::Kernel;
111		120
112	use common::sense;	121	use common::sense;
113		122
114	use Carp ();	123	use Carp ();
115		124
116	use AE ();	125	use AE ();
117		126
118	use base "Exporter";	127	use base "Exporter";
119		128
120	our $VERSION = $AnyEvent::MP::Base::VERSION;	129	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
121		130
122	our @EXPORT = qw(	131	our @EXPORT = qw(
123	NODE $NODE *SELF node_of _any_	132	NODE $NODE *SELF node_of _any_
124	resolve_node initialise_node	133	resolve_node initialise_node
125	snd rcv mon kil reg psub spawn	134	snd rcv mon kil reg psub spawn
…		…
134	kil $SELF, die => $msg;	143	kil $SELF, die => $msg;
135	}	144	}
136		145
137	=item $thisnode = NODE / $NODE	146	=item $thisnode = NODE / $NODE
138		147
139	The C<NODE> function returns, and the C<$NODE> variable contains	148	The C<NODE> function returns, and the C<$NODE> variable contains the
140	the noderef of the local node. The value is initialised by a call	149	noderef of the local node. The value is initialised by a call to
141	to C<become_public> or C<become_slave>, after which all local port	150	C<initialise_node>.
142	identifiers become invalid.
143		151
144	=item $noderef = node_of $port	152	=item $noderef = node_of $port
145		153
146	Extracts and returns the noderef from a portid or a noderef.	154	Extracts and returns the noderef from a port ID or a noderef.
147		155
148	=item initialise_node $noderef, $seednode, $seednode...	156	=item initialise_node $noderef, $seednode, $seednode...
149		157
150	=item initialise_node "slave/", $master, $master...	158	=item initialise_node "slave/", $master, $master...
151		159
…		…
154	it should know the noderefs of some other nodes in the network.	162	it should know the noderefs of some other nodes in the network.
155		163
156	This function initialises a node - it must be called exactly once (or	164	This function initialises a node - it must be called exactly once (or
157	never) before calling other AnyEvent::MP functions.	165	never) before calling other AnyEvent::MP functions.
158		166
159	All arguments are noderefs, which can be either resolved or unresolved.	167	All arguments (optionally except for the first) are noderefs, which can be
		168	either resolved or unresolved.
		169
		170	The first argument will be looked up in the configuration database first
		171	(if it is C<undef> then the current nodename will be used instead) to find
		172	the relevant configuration profile (see L<aemp>). If none is found then
		173	the default configuration is used. The configuration supplies additional
		174	seed/master nodes and can override the actual noderef.
160		175
161	There are two types of networked nodes, public nodes and slave nodes:	176	There are two types of networked nodes, public nodes and slave nodes:
162		177
163	=over 4	178	=over 4
164		179
165	=item public nodes	180	=item public nodes
166		181
167	For public nodes, C<$noderef> must either be a (possibly unresolved)	182	For public nodes, C<$noderef> (supplied either directly to
168	noderef, in which case it will be resolved, or C<undef> (or missing), in	183	C<initialise_node> or indirectly via a profile or the nodename) must be a
169	which case the noderef will be guessed.	184	noderef (possibly unresolved, in which case it will be resolved).
170		185
171	Afterwards, the node will bind itself on all endpoints and try to connect	186	After resolving, the node will bind itself on all endpoints and try to
172	to all additional C<$seednodes> that are specified. Seednodes are optional	187	connect to all additional C<$seednodes> that are specified. Seednodes are
173	and can be used to quickly bootstrap the node into an existing network.	188	optional and can be used to quickly bootstrap the node into an existing
		189	network.
174		190
175	=item slave nodes	191	=item slave nodes
176		192
177	When the C<$noderef> is the special string C<slave/>, then the node will	193	When the C<$noderef> (either as given or overriden by the config file)
		194	is the special string C<slave/>, then the node will become a slave
178	become a slave node. Slave nodes cannot be contacted from outside and will	195	node. Slave nodes cannot be contacted from outside and will route most of
179	route most of their traffic to the master node that they attach to.	196	their traffic to the master node that they attach to.
180		197
181	At least one additional noderef is required: The node will try to connect	198	At least one additional noderef is required (either by specifying it
182	to all of them and will become a slave attached to the first node it can	199	directly or because it is part of the configuration profile): The node
183	successfully connect to.	200	will try to connect to all of them and will become a slave attached to the
		201	first node it can successfully connect to.
184		202
185	=back	203	=back
186		204
187	This function will block until all nodes have been resolved and, for slave	205	This function will block until all nodes have been resolved and, for slave
188	nodes, until it has successfully established a connection to a master	206	nodes, until it has successfully established a connection to a master
189	server.	207	server.
190		208
191	Example: become a public node listening on the default node.	209	Example: become a public node listening on the guessed noderef, or the one
		210	specified via C<aemp> for the current node. This should be the most common
		211	form of invocation for "daemon"-type nodes.
192		212
193	initialise_node;	213	initialise_node;
		214
		215	Example: become a slave node to any of the the seednodes specified via
		216	C<aemp>. This form is often used for commandline clients.
		217
		218	initialise_node "slave/";
		219
		220	Example: become a slave node to any of the specified master servers. This
		221	form is also often used for commandline clients.
		222
		223	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
194		224
195	Example: become a public node, and try to contact some well-known master	225	Example: become a public node, and try to contact some well-known master
196	servers to become part of the network.	226	servers to become part of the network.
197		227
198	initialise_node undef, "master1", "master2";	228	initialise_node undef, "master1", "master2";
…		…
201		231
202	initialise_node 4041;	232	initialise_node 4041;
203		233
204	Example: become a public node, only visible on localhost port 4044.	234	Example: become a public node, only visible on localhost port 4044.
205		235
206	initialise_node "locahost:4044";	236	initialise_node "localhost:4044";
207
208	Example: become a slave node to any of the specified master servers.
209
210	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
211		237
212	=item $cv = resolve_node $noderef	238	=item $cv = resolve_node $noderef
213		239
214	Takes an unresolved node reference that may contain hostnames and	240	Takes an unresolved node reference that may contain hostnames and
215	abbreviated IDs, resolves all of them and returns a resolved node	241	abbreviated IDs, resolves all of them and returns a resolved node
…		…
252	=item snd $port, type => @data	278	=item snd $port, type => @data
253		279
254	=item snd $port, @msg	280	=item snd $port, @msg
255		281
256	Send the given message to the given port ID, which can identify either	282	Send the given message to the given port ID, which can identify either
257	a local or a remote port, and can be either a string or soemthignt hat	283	a local or a remote port, and must be a port ID.
258	stringifies a sa port ID (such as a port object :).
259		284
260	While the message can be about anything, it is highly recommended to use a	285	While the message can be about anything, it is highly recommended to use a
261	string as first element (a portid, or some word that indicates a request	286	string as first element (a port ID, or some word that indicates a request
262	type etc.).	287	type etc.).
263		288
264	The message data effectively becomes read-only after a call to this	289	The message data effectively becomes read-only after a call to this
265	function: modifying any argument is not allowed and can cause many	290	function: modifying any argument is not allowed and can cause many
266	problems.	291	problems.
…		…
271	that Storable can serialise and deserialise is allowed, and for the local	296	that Storable can serialise and deserialise is allowed, and for the local
272	node, anything can be passed.	297	node, anything can be passed.
273		298
274	=item $local_port = port	299	=item $local_port = port
275		300
276	Create a new local port object that can be used either as a pattern	301	Create a new local port object and returns its port ID. Initially it has
277	matching port ("full port") or a single-callback port ("miniport"),	302	no callbacks set and will throw an error when it receives messages.
278	depending on how C<rcv> callbacks are bound to the object.
279		303
280	=item $port = port { my @msg = @_; $finished }	304	=item $local_port = port { my @msg = @_ }
281		305
282	Creates a "miniport", that is, a very lightweight port without any pattern	306	Creates a new local port, and returns its ID. Semantically the same as
283	matching behind it, and returns its ID. Semantically the same as creating
284	a port and calling C<rcv $port, $callback> on it.	307	creating a port and calling C<rcv $port, $callback> on it.
285		308
286	The block will be called for every message received on the port. When the	309	The block will be called for every message received on the port, with the
287	callback returns a true value its job is considered "done" and the port	310	global variable C<$SELF> set to the port ID. Runtime errors will cause the
288	will be destroyed. Otherwise it will stay alive.	311	port to be C<kil>ed. The message will be passed as-is, no extra argument
		312	(i.e. no port ID) will be passed to the callback.
289		313
290	The message will be passed as-is, no extra argument (i.e. no port id) will	314	If you want to stop/destroy the port, simply C<kil> it:
291	be passed to the callback.
292		315
293	If you need the local port id in the callback, this works nicely:	316	my $port = port {
294		317	my @msg = @_;
295	my $port; $port = port {	318	...
296	snd $otherport, reply => $port;	319	kil $SELF;
297	};	320	};
298		321
299	=cut	322	=cut
300		323
301	sub rcv($@);	324	sub rcv($@);
		325
		326	sub _kilme {
		327	die "received message on port without callback";
		328	}
302		329
303	sub port(;&) {	330	sub port(;&) {
304	my $id = "$UNIQ." . $ID++;	331	my $id = "$UNIQ." . $ID++;
305	my $port = "$NODE#$id";	332	my $port = "$NODE#$id";
306		333
307	if (@_) {	334	rcv $port, shift \|\| \&_kilme;
308	rcv $port, shift;
309	} else {
310	$PORT{$id} = sub { }; # nop
311	}
312		335
313	$port	336	$port
314	}	337	}
315		338
316	=item reg $port, $name
317
318	=item reg $name
319
320	Registers the given port (or C<$SELF><<< if missing) under the name
321	C<$name>. If the name already exists it is replaced.
322
323	A port can only be registered under one well known name.
324
325	A port automatically becomes unregistered when it is killed.
326
327	=cut
328
329	sub reg(@) {
330	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
331
332	$REG{$_[0]} = $port;
333	}
334
335	=item rcv $port, $callback->(@msg)	339	=item rcv $local_port, $callback->(@msg)
336		340
337	Replaces the callback on the specified miniport (after converting it to	341	Replaces the default callback on the specified port. There is no way to
338	one if required).	342	remove the default callback: use C<sub { }> to disable it, or better
339		343	C<kil> the port when it is no longer needed.
340	=item rcv $port, tagstring => $callback->(@msg), ...
341
342	=item rcv $port, $smartmatch => $callback->(@msg), ...
343
344	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
345
346	Register callbacks to be called on matching messages on the given full
347	port (after converting it to one if required) and return the port.
348
349	The callback has to return a true value when its work is done, after
350	which is will be removed, or a false value in which case it will stay
351	registered.
352		344
353	The global C<$SELF> (exported by this module) contains C<$port> while	345	The global C<$SELF> (exported by this module) contains C<$port> while
354	executing the callback.	346	executing the callback. Runtime errors during callback execution will
		347	result in the port being C<kil>ed.
355		348
356	Runtime errors during callback execution will result in the port being	349	The default callback received all messages not matched by a more specific
357	C<kil>ed.	350	C<tag> match.
358		351
359	If the match is an array reference, then it will be matched against the	352	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
360	first elements of the message, otherwise only the first element is being
361	matched.
362		353
363	Any element in the match that is specified as C<_any_> (a function	354	Register callbacks to be called on messages starting with the given tag on
364	exported by this module) matches any single element of the message.	355	the given port (and return the port), or unregister it (when C<$callback>
		356	is C<$undef>).
365		357
366	While not required, it is highly recommended that the first matching	358	The original message will be passed to the callback, after the first
367	element is a string identifying the message. The one-string-only match is	359	element (the tag) has been removed. The callback will use the same
368	also the most efficient match (by far).	360	environment as the default callback (see above).
369		361
370	Example: create a port and bind receivers on it in one go.	362	Example: create a port and bind receivers on it in one go.
371		363
372	my $port = rcv port,	364	my $port = rcv port,
373	msg1 => sub { ...; 0 },	365	msg1 => sub { ... },
374	msg2 => sub { ...; 0 },	366	msg2 => sub { ... },
375	;	367	;
376		368
377	Example: create a port, bind receivers and send it in a message elsewhere	369	Example: create a port, bind receivers and send it in a message elsewhere
378	in one go:	370	in one go:
379		371
380	snd $otherport, reply =>	372	snd $otherport, reply =>
381	rcv port,	373	rcv port,
382	msg1 => sub { ...; 0 },	374	msg1 => sub { ... },
383	...	375	...
384	;	376	;
385		377
386	=cut	378	=cut
387		379
…		…
390	my ($noderef, $portid) = split /#/, $port, 2;	382	my ($noderef, $portid) = split /#/, $port, 2;
391		383
392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	384	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
393	or Carp::croak "$port: rcv can only be called on local ports, caught";	385	or Carp::croak "$port: rcv can only be called on local ports, caught";
394		386
395	if (@_ == 1) {	387	while (@_) {
		388	if (ref $_[0]) {
		389	if (my $self = $PORT_DATA{$portid}) {
		390	"AnyEvent::MP::Port" eq ref $self
		391	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		392
		393	$self->[2] = shift;
		394	} else {
396	my $cb = shift;	395	my $cb = shift;
397	delete $PORT_DATA{$portid};
398	$PORT{$portid} = sub {	396	$PORT{$portid} = sub {
399	local $SELF = $port;	397	local $SELF = $port;
400	eval {	398	eval { &$cb }; _self_die if $@;
401	&$cb	399	};
402	and kil $port;
403	};	400	}
404	_self_die if $@;	401	} elsif (defined $_[0]) {
405	};
406	} else {
407	my $self = $PORT_DATA{$portid} \|\|= do {	402	my $self = $PORT_DATA{$portid} \|\|= do {
408	my $self = bless {	403	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
409	id => $port,
410	}, "AnyEvent::MP::Port";
411		404
412	$PORT{$portid} = sub {	405	$PORT{$portid} = sub {
413	local $SELF = $port;	406	local $SELF = $port;
414		407
415	eval {
416	for (@{ $self->{rc0}{$_[0]} }) {	408	if (my $cb = $self->[1]{$_[0]}) {
417	$_ && &{$_->[0]}	409	shift;
418	&& undef $_;	410	eval { &$cb }; _self_die if $@;
419	}	411	} else {
420
421	for (@{ $self->{rcv}{$_[0]} }) {
422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
423	&& &{$_->[0]}	412	&{ $self->[0] };
424	&& undef $_;
425	}
426
427	for (@{ $self->{any} }) {
428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
429	&& &{$_->[0]}
430	&& undef $_;
431	}	413	}
432	};	414	};
433	_self_die if $@;	415
		416	$self
434	};	417	};
435		418
436	$self
437	};
438
439	"AnyEvent::MP::Port" eq ref $self	419	"AnyEvent::MP::Port" eq ref $self
440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	420	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
441		421
442	while (@_) {
443	my ($match, $cb) = splice @_, 0, 2;	422	my ($tag, $cb) = splice @_, 0, 2;
444		423
445	if (!ref $match) {	424	if (defined $cb) {
446	push @{ $self->{rc0}{$match} }, [$cb];	425	$self->[1]{$tag} = $cb;
447	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
448	my ($type, @match) = @$match;
449	@match
450	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
452	} else {	426	} else {
453	push @{ $self->{any} }, [$cb, $match];	427	delete $self->[1]{$tag};
454	}	428	}
455	}	429	}
456	}	430	}
457		431
458	$port	432	$port
…		…
762	convenience functionality.	736	convenience functionality.
763		737
764	This means that AEMP requires a less tightly controlled environment at the	738	This means that AEMP requires a less tightly controlled environment at the
765	cost of longer node references and a slightly higher management overhead.	739	cost of longer node references and a slightly higher management overhead.
766		740
		741	=item Erlang has a "remote ports are like local ports" philosophy, AEMP
		742	uses "local ports are like remote ports".
		743
		744	The failure modes for local ports are quite different (runtime errors
		745	only) then for remote ports - when a local port dies, you I<know> it dies,
		746	when a connection to another node dies, you know nothing about the other
		747	port.
		748
		749	Erlang pretends remote ports are as reliable as local ports, even when
		750	they are not.
		751
		752	AEMP encourages a "treat remote ports differently" philosophy, with local
		753	ports being the special case/exception, where transport errors cannot
		754	occur.
		755
767	=item * Erlang uses processes and a mailbox, AEMP does not queue.	756	=item * Erlang uses processes and a mailbox, AEMP does not queue.
768		757
769	Erlang uses processes that selctively receive messages, and therefore	758	Erlang uses processes that selectively receive messages, and therefore
770	needs a queue. AEMP is event based, queuing messages would serve no useful	759	needs a queue. AEMP is event based, queuing messages would serve no
771	purpose.	760	useful purpose. For the same reason the pattern-matching abilities of
		761	AnyEvent::MP are more limited, as there is little need to be able to
		762	filter messages without dequeing them.
772		763
773	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	764	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
774		765
775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	766	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
776		767
777	Sending messages in Erlang is synchronous and blocks the process. AEMP	768	Sending messages in Erlang is synchronous and blocks the process (and
778	sends are immediate, connection establishment is handled in the	769	so does not need a queue that can overflow). AEMP sends are immediate,
779	background.	770	connection establishment is handled in the background.
780		771
781	=item * Erlang can silently lose messages, AEMP cannot.	772	=item * Erlang suffers from silent message loss, AEMP does not.
782		773
783	Erlang makes few guarantees on messages delivery - messages can get lost	774	Erlang makes few guarantees on messages delivery - messages can get lost
784	without any of the processes realising it (i.e. you send messages a, b,	775	without any of the processes realising it (i.e. you send messages a, b,
785	and c, and the other side only receives messages a and c).	776	and c, and the other side only receives messages a and c).
786		777
…		…
798	eventually be killed - it cannot happen that a node detects a port as dead	789	eventually be killed - it cannot happen that a node detects a port as dead
799	and then later sends messages to it, finding it is still alive.	790	and then later sends messages to it, finding it is still alive.
800		791
801	=item * Erlang can send messages to the wrong port, AEMP does not.	792	=item * Erlang can send messages to the wrong port, AEMP does not.
802		793
803	In Erlang it is quite possible that a node that restarts reuses a process	794	In Erlang it is quite likely that a node that restarts reuses a process ID
804	ID known to other nodes for a completely different process, causing	795	known to other nodes for a completely different process, causing messages
805	messages destined for that process to end up in an unrelated process.	796	destined for that process to end up in an unrelated process.
806		797
807	AEMP never reuses port IDs, so old messages or old port IDs floating	798	AEMP never reuses port IDs, so old messages or old port IDs floating
808	around in the network will not be sent to an unrelated port.	799	around in the network will not be sent to an unrelated port.
809		800
810	=item * Erlang uses unprotected connections, AEMP uses secure	801	=item * Erlang uses unprotected connections, AEMP uses secure
…		…
846	This also saves round-trips and avoids sending messages to the wrong port	837	This also saves round-trips and avoids sending messages to the wrong port
847	(hard to do in Erlang).	838	(hard to do in Erlang).
848		839
849	=back	840	=back
850		841
		842	=head1 RATIONALE
		843
		844	=over 4
		845
		846	=item Why strings for ports and noderefs, why not objects?
		847
		848	We considered "objects", but found that the actual number of methods
		849	thatc an be called are very low. Since port IDs and noderefs travel over
		850	the network frequently, the serialising/deserialising would add lots of
		851	overhead, as well as having to keep a proxy object.
		852
		853	Strings can easily be printed, easily serialised etc. and need no special
		854	procedures to be "valid".
		855
		856	And a a miniport consists of a single closure stored in a global hash - it
		857	can't become much cheaper.
		858
		859	=item Why favour JSON, why not real serialising format such as Storable?
		860
		861	In fact, any AnyEvent::MP node will happily accept Storable as framing
		862	format, but currently there is no way to make a node use Storable by
		863	default.
		864
		865	The default framing protocol is JSON because a) JSON::XS is many times
		866	faster for small messages and b) most importantly, after years of
		867	experience we found that object serialisation is causing more problems
		868	than it gains: Just like function calls, objects simply do not travel
		869	easily over the network, mostly because they will always be a copy, so you
		870	always have to re-think your design.
		871
		872	Keeping your messages simple, concentrating on data structures rather than
		873	objects, will keep your messages clean, tidy and efficient.
		874
		875	=back
		876
851	=head1 SEE ALSO	877	=head1 SEE ALSO
852		878
853	L<AnyEvent>.	879	L<AnyEvent>.
854		880
855	=head1 AUTHOR	881	=head1 AUTHOR

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs. Revision 1.52 by root, Fri Aug 14 15:13:20 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs.
Revision 1.52 by root, Fri Aug 14 15:13:20 2009 UTC