Commit | Line | Data |
9e447f9d |
1 | #!/usr/bin/perl |
2 | |
3 | package Catalyst::Plugin::Session; |
4 | use base qw/Class::Accessor::Fast/; |
5 | |
6 | use strict; |
7 | use warnings; |
8 | |
9 | use NEXT; |
10 | use Catalyst::Exception (); |
9a9252c2 |
11 | use Digest (); |
12 | use overload (); |
d44bc687 |
13 | use Object::Signature (); |
9e447f9d |
14 | |
b1cd7d77 |
15 | our $VERSION = "0.02"; |
37160715 |
16 | |
9e447f9d |
17 | BEGIN { |
d44bc687 |
18 | __PACKAGE__->mk_accessors(qw/ |
19 | _sessionid |
20 | _session |
21 | _session_expires |
22 | _session_data_sig |
23 | _session_delete_reason |
24 | _flash |
25 | _flash_stale_keys |
26 | /); |
9e447f9d |
27 | } |
28 | |
29 | sub setup { |
9a9252c2 |
30 | my $c = shift; |
31 | |
32 | $c->NEXT::setup(@_); |
33 | |
34 | $c->check_session_plugin_requirements; |
35 | $c->setup_session; |
36 | |
37 | return $c; |
9e447f9d |
38 | } |
39 | |
40 | sub check_session_plugin_requirements { |
9a9252c2 |
41 | my $c = shift; |
9e447f9d |
42 | |
9a9252c2 |
43 | unless ( $c->isa("Catalyst::Plugin::Session::State") |
44 | && $c->isa("Catalyst::Plugin::Session::Store") ) |
45 | { |
46 | my $err = |
47 | ( "The Session plugin requires both Session::State " |
48 | . "and Session::Store plugins to be used as well." ); |
9e447f9d |
49 | |
9a9252c2 |
50 | $c->log->fatal($err); |
51 | Catalyst::Exception->throw($err); |
52 | } |
9e447f9d |
53 | } |
54 | |
55 | sub setup_session { |
9a9252c2 |
56 | my $c = shift; |
9e447f9d |
57 | |
9a9252c2 |
58 | my $cfg = ( $c->config->{session} ||= {} ); |
9e447f9d |
59 | |
9a9252c2 |
60 | %$cfg = ( |
61 | expires => 7200, |
62 | verify_address => 1, |
63 | %$cfg, |
64 | ); |
9e447f9d |
65 | |
9a9252c2 |
66 | $c->NEXT::setup_session(); |
9e447f9d |
67 | } |
68 | |
19c130c2 |
69 | sub prepare_action { |
70 | my $c = shift; |
71 | |
72 | if ( $c->config->{session}{flash_to_stash} and $c->_sessionid and my $flash_data = $c->flash ) { |
73 | @{ $c->stash }{ keys %$flash_data } = values %$flash_data; |
74 | } |
75 | |
76 | $c->NEXT::prepare_action(@_); |
77 | } |
78 | |
9e447f9d |
79 | sub finalize { |
9a9252c2 |
80 | my $c = shift; |
9e447f9d |
81 | |
9b0fa2a6 |
82 | $c->_save_session; |
83 | $c->_save_flash; |
84 | |
85 | $c->NEXT::finalize(@_); |
86 | } |
87 | |
88 | sub _save_session { |
89 | my $c = shift; |
90 | |
ea972e9a |
91 | if ( my $sid = $c->_sessionid ) { |
92 | if ( my $session_data = $c->_session ) { |
9e447f9d |
93 | |
ea972e9a |
94 | # all sessions are extended at the end of the request |
95 | my $now = time; |
d44bc687 |
96 | $c->store_session_data( "expires:$sid" => ( $c->config->{session}{expires} + $now ) ); |
9b0fa2a6 |
97 | |
d44bc687 |
98 | my $new_sig = Object::Signature::signature( $session_data ); |
99 | |
100 | no warnings 'uninitialized'; |
101 | if ( $new_sig ne $c->_session_data_sig ) { |
102 | $session_data->{__updated} = $now; |
103 | $c->store_session_data( "session:$sid" => $session_data ); |
104 | } |
ea972e9a |
105 | } |
9a9252c2 |
106 | } |
9b0fa2a6 |
107 | } |
9a9252c2 |
108 | |
9b0fa2a6 |
109 | sub _save_flash { |
110 | my $c = shift; |
111 | |
ea972e9a |
112 | if ( my $sid = $c->_sessionid ) { |
113 | if ( my $flash_data = $c->_flash ) { |
114 | if ( %$flash_data ) { # damn 'my' declarations |
115 | delete @{ $flash_data }{ @{ $c->_flash_stale_keys || [] } }; |
116 | $c->store_session_data( "flash:$sid", $flash_data ); |
117 | } |
118 | } else { |
119 | $c->delete_session_data( "flash:$sid" ); |
120 | } |
9b0fa2a6 |
121 | } |
9e447f9d |
122 | } |
123 | |
b7acf64e |
124 | sub _load_session { |
125 | my $c = shift; |
126 | |
29d15411 |
127 | if ( my $sid = $c->_sessionid ) { |
0974ac06 |
128 | no warnings 'uninitialized'; # ne __address |
d44bc687 |
129 | |
d5ecbf7e |
130 | my ( $session_data, $session_expires ) = map { $c->get_session_data( "${_}:${sid}" ) } qw/session expires/; |
d44bc687 |
131 | $c->_session( $session_data ); |
0974ac06 |
132 | |
d44bc687 |
133 | if ( !$session_data or $session_expires < time ) { |
3f182468 |
134 | |
135 | # session expired |
136 | $c->log->debug("Deleting session $sid (expired)") if $c->debug; |
137 | $c->delete_session("session expired"); |
138 | } |
29543a62 |
139 | elsif ($c->config->{session}{verify_address} |
0974ac06 |
140 | && $session_data->{__address} ne $c->request->address ) |
3f182468 |
141 | { |
142 | $c->log->warn( |
143 | "Deleting session $sid due to address mismatch (" |
0974ac06 |
144 | . $session_data->{__address} . " != " |
3f182468 |
145 | . $c->request->address . ")", |
146 | ); |
147 | $c->delete_session("address mismatch"); |
148 | } |
29543a62 |
149 | else { |
150 | $c->log->debug(qq/Restored session "$sid"/) if $c->debug; |
d44bc687 |
151 | $c->_session_data_sig( Object::Signature::signature( $session_data ) ); |
152 | $c->_expire_session_keys; |
29543a62 |
153 | } |
b7acf64e |
154 | |
29d15411 |
155 | return $session_data; |
9a9252c2 |
156 | } |
29d15411 |
157 | |
158 | return undef; |
b7acf64e |
159 | } |
9a9252c2 |
160 | |
9b0fa2a6 |
161 | sub _load_flash { |
162 | my $c = shift; |
163 | |
164 | if ( my $sid = $c->_sessionid ) { |
ea972e9a |
165 | if ( my $flash_data = $c->_flash || $c->_flash( $c->get_session_data( "flash:$sid" ) ) ) { |
9b0fa2a6 |
166 | $c->_flash_stale_keys([ keys %$flash_data ]); |
167 | return $flash_data; |
168 | } |
169 | } |
170 | |
171 | return undef; |
172 | } |
173 | |
d44bc687 |
174 | sub _expire_session_keys { |
b7acf64e |
175 | my ( $c, $data ) = @_; |
176 | |
177 | my $now = time; |
178 | |
179 | my $expiry = ($data || $c->_session || {})->{__expire_keys} || {}; |
180 | foreach my $key (grep { $expiry->{$_} < $now } keys %$expiry ) { |
181 | delete $c->_session->{$key}; |
182 | delete $expiry->{$key}; |
183 | } |
9e447f9d |
184 | } |
185 | |
186 | sub delete_session { |
9a9252c2 |
187 | my ( $c, $msg ) = @_; |
9e447f9d |
188 | |
9a9252c2 |
189 | # delete the session data |
29d15411 |
190 | my $sid = $c->_sessionid || return; |
9b0fa2a6 |
191 | $c->delete_session_data( "session:$sid" ); |
9e447f9d |
192 | |
9a9252c2 |
193 | # reset the values in the context object |
0974ac06 |
194 | $c->_session(undef); |
195 | $c->_sessionid(undef); |
29d15411 |
196 | $c->_session_delete_reason($msg); |
197 | } |
198 | |
199 | sub session_delete_reason { |
200 | my $c = shift; |
201 | |
202 | $c->_load_session if ( $c->_sessionid && !$c->_session ); # must verify session data |
203 | |
204 | $c->_session_delete_reason( @_ ); |
9e447f9d |
205 | } |
206 | |
0974ac06 |
207 | sub sessionid { |
208 | my $c = shift; |
29d15411 |
209 | |
0974ac06 |
210 | if ( @_ ) { |
211 | if ( $c->validate_session_id( my $sid = shift ) ) { |
29d15411 |
212 | $c->_sessionid( $sid ); |
213 | return unless defined wantarray; |
0974ac06 |
214 | } else { |
215 | my $err = "Tried to set invalid session ID '$sid'"; |
216 | $c->log->error( $err ); |
217 | Catalyst::Exception->throw( $err ); |
218 | } |
219 | } |
29d15411 |
220 | |
221 | $c->_load_session if ( $c->_sessionid && !$c->_session ); # must verify session data |
0974ac06 |
222 | |
223 | return $c->_sessionid; |
224 | } |
225 | |
226 | sub validate_session_id { |
227 | my ( $c, $sid ) = @_; |
228 | |
ea972e9a |
229 | $sid and $sid =~ /^[a-f\d]+$/i; |
0974ac06 |
230 | } |
231 | |
9e447f9d |
232 | sub session { |
9a9252c2 |
233 | my $c = shift; |
9e447f9d |
234 | |
29d15411 |
235 | $c->_session || $c->_load_session || do { |
78476ce0 |
236 | $c->create_session_id; |
9e447f9d |
237 | |
29d15411 |
238 | $c->initialize_session_data; |
0974ac06 |
239 | }; |
9e447f9d |
240 | } |
241 | |
873f7011 |
242 | sub flash { |
243 | my $c = shift; |
78476ce0 |
244 | $c->_flash || $c->_load_flash || do { |
245 | $c->create_session_id; |
246 | $c->_flash( {} ); |
247 | } |
873f7011 |
248 | } |
249 | |
b7acf64e |
250 | sub session_expire_key { |
251 | my ( $c, %keys ) = @_; |
252 | |
253 | my $now = time; |
254 | @{ $c->session->{__expire_keys} }{keys %keys} = map { $now + $_ } values %keys; |
255 | } |
256 | |
9e447f9d |
257 | sub initialize_session_data { |
9a9252c2 |
258 | my $c = shift; |
9e447f9d |
259 | |
9a9252c2 |
260 | my $now = time; |
9e447f9d |
261 | |
0974ac06 |
262 | return $c->_session({ |
9a9252c2 |
263 | __created => $now, |
264 | __updated => $now, |
9e447f9d |
265 | |
9a9252c2 |
266 | ( |
267 | $c->config->{session}{verify_address} |
268 | ? ( __address => $c->request->address ) |
269 | : () |
270 | ), |
0974ac06 |
271 | }); |
9e447f9d |
272 | } |
273 | |
9e447f9d |
274 | sub generate_session_id { |
275 | my $c = shift; |
276 | |
277 | my $digest = $c->_find_digest(); |
278 | $digest->add( $c->session_hash_seed() ); |
279 | return $digest->hexdigest; |
280 | } |
281 | |
78476ce0 |
282 | sub create_session_id { |
283 | my $c = shift; |
284 | |
285 | if ( !$c->_sessionid ) { |
286 | my $sid = $c->generate_session_id; |
287 | |
288 | $c->log->debug(qq/Created session "$sid"/) if $c->debug; |
289 | |
290 | $c->sessionid($sid); |
291 | } |
292 | } |
293 | |
9e447f9d |
294 | my $counter; |
9a9252c2 |
295 | |
9e447f9d |
296 | sub session_hash_seed { |
9a9252c2 |
297 | my $c = shift; |
298 | |
299 | return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), ); |
9e447f9d |
300 | } |
301 | |
302 | my $usable; |
9a9252c2 |
303 | |
9e447f9d |
304 | sub _find_digest () { |
9a9252c2 |
305 | unless ($usable) { |
d44bc687 |
306 | foreach my $alg (qw/SHA-1 SHA-256 MD5/) { |
7d139eeb |
307 | eval { |
5faaa4b0 |
308 | Digest->new($alg); |
29543a62 |
309 | }; |
5faaa4b0 |
310 | unless ($@) { |
311 | $usable = $alg; |
312 | last; |
313 | } |
7d139eeb |
314 | } |
315 | $usable |
9a9252c2 |
316 | or Catalyst::Exception->throw( |
317 | "Could not find a suitable Digest module. Please install " |
318 | . "Digest::SHA1, Digest::SHA, or Digest::MD5" ); |
319 | } |
9e447f9d |
320 | |
321 | return Digest->new($usable); |
322 | } |
323 | |
99b2191e |
324 | sub dump_these { |
325 | my $c = shift; |
326 | |
327 | ( |
328 | $c->NEXT::dump_these(), |
329 | |
330 | $c->sessionid |
331 | ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], ) |
332 | : () |
333 | ); |
334 | } |
335 | |
9e447f9d |
336 | __PACKAGE__; |
337 | |
338 | __END__ |
339 | |
340 | =pod |
341 | |
342 | =head1 NAME |
343 | |
344 | Catalyst::Plugin::Session - Generic Session plugin - ties together server side |
fb1a4ac3 |
345 | storage and client side state required to maintain session data. |
9e447f9d |
346 | |
347 | =head1 SYNOPSIS |
348 | |
8f0b4c16 |
349 | # To get sessions to "just work", all you need to do is use these plugins: |
350 | |
351 | use Catalyst qw/ |
352 | Session |
353 | Session::Store::FastMmap |
354 | Session::State::Cookie |
355 | /; |
356 | |
357 | # you can replace Store::FastMmap with Store::File - both have sensible |
358 | # default configurations (see their docs for details) |
359 | |
360 | # more complicated backends are available for other scenarios (DBI storage, |
361 | # etc) |
362 | |
363 | |
364 | # after you've loaded the plugins you can save session data |
365 | # For example, if you are writing a shopping cart, it could be implemented |
366 | # like this: |
9e447f9d |
367 | |
229a5b53 |
368 | sub add_item : Local { |
369 | my ( $self, $c ) = @_; |
370 | |
371 | my $item_id = $c->req->param("item"); |
372 | |
8f0b4c16 |
373 | # $c->session is a hash ref, a bit like $c->stash |
374 | # the difference is that it' preserved across requests |
229a5b53 |
375 | |
376 | push @{ $c->session->{items} }, $item_id; |
377 | |
378 | $c->forward("MyView"); |
379 | } |
380 | |
381 | sub display_items : Local { |
382 | my ( $self, $c ) = @_; |
383 | |
384 | # values in $c->session are restored |
385 | $c->stash->{items_to_display} = |
8f0b4c16 |
386 | [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ]; |
229a5b53 |
387 | |
388 | $c->forward("MyView"); |
389 | } |
390 | |
9e447f9d |
391 | =head1 DESCRIPTION |
392 | |
393 | The Session plugin is the base of two related parts of functionality required |
394 | for session management in web applications. |
395 | |
396 | The first part, the State, is getting the browser to repeat back a session key, |
397 | so that the web application can identify the client and logically string |
398 | several requests together into a session. |
399 | |
400 | The second part, the Store, deals with the actual storage of information about |
401 | the client. This data is stored so that the it may be revived for every request |
402 | made by the same client. |
403 | |
404 | This plugin links the two pieces together. |
405 | |
8f0b4c16 |
406 | =head1 RECCOMENDED BACKENDS |
407 | |
408 | =over 4 |
409 | |
410 | =item Session::State::Cookie |
411 | |
412 | The only really sane way to do state is using cookies. |
413 | |
414 | =item Session::Store::File |
415 | |
416 | A portable backend, based on Cache::File. |
417 | |
418 | =item Session::Store::FastMmap |
419 | |
420 | A fast and flexible backend, based on Cache::FastMmap. |
421 | |
422 | =back |
423 | |
9e447f9d |
424 | =head1 METHODS |
425 | |
426 | =over 4 |
427 | |
428 | =item sessionid |
429 | |
430 | An accessor for the session ID value. |
431 | |
432 | =item session |
433 | |
434 | Returns a hash reference that might contain unserialized values from previous |
435 | requests in the same session, and whose modified value will be saved for future |
436 | requests. |
437 | |
438 | This method will automatically create a new session and session ID if none |
439 | exists. |
440 | |
07e714d2 |
441 | =item flash |
442 | |
443 | This is like Ruby on Rails' flash data structure. Think of it as a stash that |
444 | lasts a single redirect, not only a forward. |
445 | |
446 | sub moose : Local { |
447 | my ( $self, $c ) = @_; |
448 | |
449 | $c->flash->{beans} = 10; |
450 | $c->response->redirect( $c->uri_for("foo") ); |
451 | } |
452 | |
453 | sub foo : Local { |
454 | my ( $self, $c ) = @_; |
455 | |
456 | my $value = $c->flash->{beans}; |
457 | |
458 | # ... |
459 | |
460 | $c->response->redirect( $c->uri_for("bar") ); |
461 | } |
462 | |
463 | sub bar : Local { |
464 | my ( $self, $c ) = @_; |
465 | |
466 | if ( exists $c->flash->{beans} ) { # false |
467 | |
468 | } |
469 | } |
470 | |
9e447f9d |
471 | =item session_delete_reason |
472 | |
473 | This accessor contains a string with the reason a session was deleted. Possible |
474 | values include: |
475 | |
476 | =over 4 |
477 | |
478 | =item * |
479 | |
480 | C<address mismatch> |
481 | |
482 | =item * |
483 | |
484 | C<session expired> |
485 | |
486 | =back |
487 | |
b7acf64e |
488 | =item session_expire_key $key, $ttl |
489 | |
490 | Mark a key to expire at a certain time (only useful when shorter than the |
491 | expiry time for the whole session). |
492 | |
493 | For example: |
494 | |
495 | __PACKAGE__->config->{session}{expires} = 1000000000000; # forever |
496 | |
497 | # later |
498 | |
499 | $c->session_expire_key( __user => 3600 ); |
500 | |
501 | Will make the session data survive, but the user will still be logged out after |
502 | an hour. |
503 | |
504 | Note that these values are not auto extended. |
505 | |
8f0b4c16 |
506 | =back |
507 | |
508 | =item INTERNAL METHODS |
509 | |
510 | =over 4 |
511 | |
9e447f9d |
512 | =item setup |
513 | |
514 | This method is extended to also make calls to |
515 | C<check_session_plugin_requirements> and C<setup_session>. |
516 | |
517 | =item check_session_plugin_requirements |
518 | |
519 | This method ensures that a State and a Store plugin are also in use by the |
520 | application. |
521 | |
522 | =item setup_session |
523 | |
524 | This method populates C<< $c->config->{session} >> with the default values |
525 | listed in L</CONFIGURATION>. |
526 | |
527 | =item prepare_action |
528 | |
68fd02ae |
529 | This methoid is extended. |
530 | |
531 | It's only effect is if the (off by default) C<flash_to_stash> configuration |
532 | parameter is on - then it will copy the contents of the flash to the stash at |
533 | prepare time. |
9e447f9d |
534 | |
535 | =item finalize |
536 | |
537 | This method is extended and will extend the expiry time, as well as persist the |
538 | session data if a session exists. |
539 | |
540 | =item delete_session REASON |
541 | |
542 | This method is used to invalidate a session. It takes an optional parameter |
543 | which will be saved in C<session_delete_reason> if provided. |
544 | |
545 | =item initialize_session_data |
546 | |
547 | This method will initialize the internal structure of the session, and is |
548 | called by the C<session> method if appropriate. |
549 | |
68fd02ae |
550 | =item create_session_id |
551 | |
552 | Creates a new session id using C<generate_session_id> if there is no session ID |
553 | yet. |
554 | |
229a5b53 |
555 | =item generate_session_id |
556 | |
557 | This method will return a string that can be used as a session ID. It is |
558 | supposed to be a reasonably random string with enough bits to prevent |
559 | collision. It basically takes C<session_hash_seed> and hashes it using SHA-1, |
560 | MD5 or SHA-256, depending on the availibility of these modules. |
561 | |
562 | =item session_hash_seed |
563 | |
564 | This method is actually rather internal to generate_session_id, but should be |
565 | overridable in case you want to provide more random data. |
566 | |
567 | Currently it returns a concatenated string which contains: |
568 | |
0974ac06 |
569 | =item validate_session_id SID |
570 | |
571 | Make sure a session ID is of the right format. |
572 | |
573 | This currently ensures that the session ID string is any amount of case |
574 | insensitive hexadecimal characters. |
575 | |
229a5b53 |
576 | =over 4 |
577 | |
578 | =item * |
579 | |
580 | A counter |
581 | |
582 | =item * |
583 | |
584 | The current time |
585 | |
586 | =item * |
587 | |
588 | One value from C<rand>. |
589 | |
590 | =item * |
591 | |
592 | The stringified value of a newly allocated hash reference |
593 | |
594 | =item * |
595 | |
596 | The stringified value of the Catalyst context object |
597 | |
598 | =back |
599 | |
600 | In the hopes that those combined values are entropic enough for most uses. If |
601 | this is not the case you can replace C<session_hash_seed> with e.g. |
602 | |
603 | sub session_hash_seed { |
604 | open my $fh, "<", "/dev/random"; |
605 | read $fh, my $bytes, 20; |
606 | close $fh; |
607 | return $bytes; |
608 | } |
609 | |
610 | Or even more directly, replace C<generate_session_id>: |
611 | |
612 | sub generate_session_id { |
613 | open my $fh, "<", "/dev/random"; |
614 | read $fh, my $bytes, 20; |
615 | close $fh; |
616 | return unpack("H*", $bytes); |
617 | } |
618 | |
619 | Also have a look at L<Crypt::Random> and the various openssl bindings - these |
620 | modules provide APIs for cryptographically secure random data. |
621 | |
99b2191e |
622 | =item dump_these |
623 | |
624 | See L<Catalyst/dump_these> - ammends the session data structure to the list of |
625 | dumped objects if session ID is defined. |
626 | |
9e447f9d |
627 | =back |
628 | |
a92c8aeb |
629 | =head1 USING SESSIONS DURING PREPARE |
630 | |
631 | The earliest point in time at which you may use the session data is after |
632 | L<Catalyst::Plugin::Session>'s C<prepare_action> has finished. |
633 | |
634 | State plugins must set $c->session ID before C<prepare_action>, and during |
635 | C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from |
636 | the store. |
637 | |
638 | sub prepare_action { |
639 | my $c = shift; |
640 | |
641 | # don't touch $c->session yet! |
b1cd7d77 |
642 | |
a92c8aeb |
643 | $c->NEXT::prepare_action( @_ ); |
644 | |
645 | $c->session; # this is OK |
646 | $c->sessionid; # this is also OK |
647 | } |
648 | |
9e447f9d |
649 | =head1 CONFIGURATION |
650 | |
229a5b53 |
651 | $c->config->{session} = { |
652 | expires => 1234, |
653 | }; |
9e447f9d |
654 | |
655 | All configuation parameters are provided in a hash reference under the |
656 | C<session> key in the configuration hash. |
657 | |
658 | =over 4 |
659 | |
660 | =item expires |
661 | |
662 | The time-to-live of each session, expressed in seconds. Defaults to 7200 (two |
663 | hours). |
664 | |
665 | =item verify_address |
666 | |
8c7e922c |
667 | When true, C<<$c->request->address>> will be checked at prepare time. If it is |
668 | not the same as the address that initiated the session, the session is deleted. |
9e447f9d |
669 | |
68fd02ae |
670 | =item flash_to_stash |
671 | |
672 | This option makes it easier to have actions behave the same whether they were |
673 | forwarded to or redirected to. On prepare time it copies the contents of |
674 | C<flash> (if any) to the stash. |
675 | |
9e447f9d |
676 | =back |
677 | |
678 | =head1 SPECIAL KEYS |
679 | |
680 | The hash reference returned by C<< $c->session >> contains several keys which |
681 | are automatically set: |
682 | |
683 | =over 4 |
684 | |
685 | =item __expires |
686 | |
d44bc687 |
687 | This key no longer exists. This data is now saved elsewhere. |
9e447f9d |
688 | |
689 | =item __updated |
690 | |
d44bc687 |
691 | The last time a session was saved to the store. |
9e447f9d |
692 | |
693 | =item __created |
694 | |
695 | The time when the session was first created. |
696 | |
697 | =item __address |
698 | |
699 | The value of C<< $c->request->address >> at the time the session was created. |
8c7e922c |
700 | This value is only populated if C<verify_address> is true in the configuration. |
9e447f9d |
701 | |
702 | =back |
703 | |
c80e9f04 |
704 | =head1 CAVEATS |
705 | |
a552e4b5 |
706 | =head2 Round the Robin Proxies |
707 | |
c80e9f04 |
708 | C<verify_address> could make your site inaccessible to users who are behind |
709 | load balanced proxies. Some ISPs may give a different IP to each request by the |
710 | same client due to this type of proxying. If addresses are verified these |
711 | users' sessions cannot persist. |
712 | |
713 | To let these users access your site you can either disable address verification |
714 | as a whole, or provide a checkbox in the login dialog that tells the server |
715 | that it's OK for the address of the client to change. When the server sees that |
716 | this box is checked it should delete the C<__address> sepcial key from the |
717 | session hash when the hash is first created. |
718 | |
a552e4b5 |
719 | =head2 Race Conditions |
720 | |
721 | In this day and age where cleaning detergents and dutch football (not the |
722 | american kind) teams roam the plains in great numbers, requests may happen |
723 | simultaneously. This means that there is some risk of session data being |
724 | overwritten, like this: |
725 | |
726 | =over 4 |
727 | |
728 | =item 1. |
729 | |
730 | request a starts, request b starts, with the same session id |
731 | |
732 | =item 2. |
733 | |
734 | session data is loaded in request a |
735 | |
736 | =item 3. |
737 | |
738 | session data is loaded in request b |
739 | |
740 | =item 4. |
741 | |
742 | session data is changed in request a |
743 | |
744 | =item 5. |
745 | |
746 | request a finishes, session data is updated and written to store |
747 | |
748 | =item 6. |
749 | |
750 | request b finishes, session data is updated and written to store, overwriting |
751 | changes by request a |
752 | |
753 | =back |
754 | |
755 | If this is a concern in your application, a soon to be developed locking |
756 | solution is the only safe way to go. This will have a bigger overhead. |
757 | |
758 | For applications where any given user is only making one request at a time this |
759 | plugin should be safe enough. |
760 | |
d45028d6 |
761 | =head1 AUTHORS |
762 | |
baa9db9c |
763 | =over 4 |
764 | |
765 | =item Andy Grundman |
766 | |
767 | =item Christian Hansen |
768 | |
769 | =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer) |
770 | |
771 | =item Sebastian Riedel |
772 | |
773 | =back |
774 | |
775 | And countless other contributers from #catalyst. Thanks guys! |
d45028d6 |
776 | |
cc40ae4b |
777 | =head1 COPYRIGHT & LICENSE |
d45028d6 |
778 | |
779 | Copyright (c) 2005 the aforementioned authors. All rights |
780 | reserved. This program is free software; you can redistribute |
781 | it and/or modify it under the same terms as Perl itself. |
782 | |
9e447f9d |
783 | =cut |
784 | |
785 | |