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 | |
d0e0cfb8 |
15 | our $VERSION = "0.04"; |
37160715 |
16 | |
9e447f9d |
17 | BEGIN { |
4207ce8d |
18 | __PACKAGE__->mk_accessors( |
19 | qw/ |
20 | _sessionid |
21 | _session |
22 | _session_expires |
23 | _session_data_sig |
24 | _session_delete_reason |
25 | _flash |
26 | _flash_stale_keys |
27 | / |
28 | ); |
9e447f9d |
29 | } |
30 | |
31 | sub setup { |
9a9252c2 |
32 | my $c = shift; |
33 | |
34 | $c->NEXT::setup(@_); |
35 | |
36 | $c->check_session_plugin_requirements; |
37 | $c->setup_session; |
38 | |
39 | return $c; |
9e447f9d |
40 | } |
41 | |
42 | sub check_session_plugin_requirements { |
9a9252c2 |
43 | my $c = shift; |
9e447f9d |
44 | |
9a9252c2 |
45 | unless ( $c->isa("Catalyst::Plugin::Session::State") |
46 | && $c->isa("Catalyst::Plugin::Session::Store") ) |
47 | { |
48 | my $err = |
49 | ( "The Session plugin requires both Session::State " |
50 | . "and Session::Store plugins to be used as well." ); |
9e447f9d |
51 | |
9a9252c2 |
52 | $c->log->fatal($err); |
53 | Catalyst::Exception->throw($err); |
54 | } |
9e447f9d |
55 | } |
56 | |
57 | sub setup_session { |
9a9252c2 |
58 | my $c = shift; |
9e447f9d |
59 | |
9a9252c2 |
60 | my $cfg = ( $c->config->{session} ||= {} ); |
9e447f9d |
61 | |
9a9252c2 |
62 | %$cfg = ( |
63 | expires => 7200, |
64 | verify_address => 1, |
65 | %$cfg, |
66 | ); |
9e447f9d |
67 | |
9a9252c2 |
68 | $c->NEXT::setup_session(); |
9e447f9d |
69 | } |
70 | |
19c130c2 |
71 | sub prepare_action { |
72 | my $c = shift; |
73 | |
4207ce8d |
74 | if ( $c->config->{session}{flash_to_stash} |
75 | and $c->_sessionid |
76 | and my $flash_data = $c->flash ) |
77 | { |
19c130c2 |
78 | @{ $c->stash }{ keys %$flash_data } = values %$flash_data; |
79 | } |
80 | |
81 | $c->NEXT::prepare_action(@_); |
82 | } |
83 | |
9e447f9d |
84 | sub finalize { |
9a9252c2 |
85 | my $c = shift; |
9e447f9d |
86 | |
9b0fa2a6 |
87 | $c->_save_session; |
88 | $c->_save_flash; |
89 | |
90 | $c->NEXT::finalize(@_); |
91 | } |
92 | |
93 | sub _save_session { |
94 | my $c = shift; |
4207ce8d |
95 | |
ea972e9a |
96 | if ( my $sid = $c->_sessionid ) { |
97 | if ( my $session_data = $c->_session ) { |
9e447f9d |
98 | |
ea972e9a |
99 | # all sessions are extended at the end of the request |
100 | my $now = time; |
7a02371f |
101 | |
102 | # the ref is a workaround for FastMmap: |
103 | # FastMmap can't store values which aren't refs |
104 | # this yields errors and other great suckage |
105 | $c->store_session_data( "expires:$sid" => |
106 | ( { expires => $c->config->{session}{expires} + $now } ) ); |
d44bc687 |
107 | |
108 | no warnings 'uninitialized'; |
4207ce8d |
109 | if ( Object::Signature::signature($session_data) ne |
110 | $c->_session_data_sig ) |
111 | { |
d44bc687 |
112 | $session_data->{__updated} = $now; |
113 | $c->store_session_data( "session:$sid" => $session_data ); |
114 | } |
ea972e9a |
115 | } |
9a9252c2 |
116 | } |
9b0fa2a6 |
117 | } |
9a9252c2 |
118 | |
9b0fa2a6 |
119 | sub _save_flash { |
120 | my $c = shift; |
121 | |
ea972e9a |
122 | if ( my $sid = $c->_sessionid ) { |
4207ce8d |
123 | my $flash_data = $c->_flash || {}; |
124 | |
125 | delete @{$flash_data}{ @{ $c->_flash_stale_keys || [] } }; |
126 | |
127 | if (%$flash_data) { # damn 'my' declarations |
128 | $c->store_session_data( "flash:$sid", $flash_data ); |
129 | } |
130 | else { |
131 | $c->delete_session_data("flash:$sid"); |
ea972e9a |
132 | } |
9b0fa2a6 |
133 | } |
9e447f9d |
134 | } |
135 | |
b7acf64e |
136 | sub _load_session { |
137 | my $c = shift; |
138 | |
29d15411 |
139 | if ( my $sid = $c->_sessionid ) { |
4207ce8d |
140 | no warnings 'uninitialized'; # ne __address |
141 | |
7a02371f |
142 | # see above for explanation of the workaround for FastMmap problem |
143 | my $session_expires = |
144 | ( $c->get_session_data("expires:$sid") || { expires => 0 } ) |
145 | ->{expires}; |
0974ac06 |
146 | |
4207ce8d |
147 | if ( $session_expires < time ) { |
3f182468 |
148 | |
149 | # session expired |
150 | $c->log->debug("Deleting session $sid (expired)") if $c->debug; |
151 | $c->delete_session("session expired"); |
4207ce8d |
152 | return; |
3f182468 |
153 | } |
4207ce8d |
154 | |
155 | my $session_data = $c->get_session_data("session:$sid"); |
156 | $c->_session($session_data); |
157 | |
158 | if ( $c->config->{session}{verify_address} |
0974ac06 |
159 | && $session_data->{__address} ne $c->request->address ) |
3f182468 |
160 | { |
161 | $c->log->warn( |
162 | "Deleting session $sid due to address mismatch (" |
0974ac06 |
163 | . $session_data->{__address} . " != " |
3f182468 |
164 | . $c->request->address . ")", |
165 | ); |
166 | $c->delete_session("address mismatch"); |
4207ce8d |
167 | return; |
3f182468 |
168 | } |
4207ce8d |
169 | |
170 | $c->log->debug(qq/Restored session "$sid"/) if $c->debug; |
171 | $c->_session_data_sig( Object::Signature::signature($session_data) ); |
172 | $c->_expire_session_keys; |
b7acf64e |
173 | |
29d15411 |
174 | return $session_data; |
9a9252c2 |
175 | } |
29d15411 |
176 | |
4207ce8d |
177 | return; |
b7acf64e |
178 | } |
9a9252c2 |
179 | |
9b0fa2a6 |
180 | sub _load_flash { |
181 | my $c = shift; |
182 | |
183 | if ( my $sid = $c->_sessionid ) { |
4207ce8d |
184 | if ( my $flash_data = $c->_flash |
185 | || $c->_flash( $c->get_session_data("flash:$sid") ) ) |
186 | { |
187 | $c->_flash_stale_keys( [ keys %$flash_data ] ); |
9b0fa2a6 |
188 | return $flash_data; |
189 | } |
190 | } |
191 | |
192 | return undef; |
193 | } |
194 | |
d44bc687 |
195 | sub _expire_session_keys { |
b7acf64e |
196 | my ( $c, $data ) = @_; |
197 | |
198 | my $now = time; |
199 | |
4207ce8d |
200 | my $expiry = ( $data || $c->_session || {} )->{__expire_keys} || {}; |
201 | foreach my $key ( grep { $expiry->{$_} < $now } keys %$expiry ) { |
b7acf64e |
202 | delete $c->_session->{$key}; |
203 | delete $expiry->{$key}; |
204 | } |
9e447f9d |
205 | } |
206 | |
207 | sub delete_session { |
9a9252c2 |
208 | my ( $c, $msg ) = @_; |
9e447f9d |
209 | |
9a9252c2 |
210 | # delete the session data |
29d15411 |
211 | my $sid = $c->_sessionid || return; |
4207ce8d |
212 | $c->delete_session_data("${_}:${sid}") for qw/session expires flash/; |
9e447f9d |
213 | |
9a9252c2 |
214 | # reset the values in the context object |
0974ac06 |
215 | $c->_session(undef); |
216 | $c->_sessionid(undef); |
29d15411 |
217 | $c->_session_delete_reason($msg); |
218 | } |
219 | |
220 | sub session_delete_reason { |
221 | my $c = shift; |
222 | |
4207ce8d |
223 | $c->_load_session |
224 | if ( $c->_sessionid && !$c->_session ); # must verify session data |
29d15411 |
225 | |
4207ce8d |
226 | $c->_session_delete_reason(@_); |
9e447f9d |
227 | } |
228 | |
0974ac06 |
229 | sub sessionid { |
4207ce8d |
230 | my $c = shift; |
231 | |
232 | if (@_) { |
233 | if ( $c->validate_session_id( my $sid = shift ) ) { |
234 | $c->_sessionid($sid); |
29d15411 |
235 | return unless defined wantarray; |
4207ce8d |
236 | } |
237 | else { |
238 | my $err = "Tried to set invalid session ID '$sid'"; |
239 | $c->log->error($err); |
240 | Catalyst::Exception->throw($err); |
241 | } |
242 | } |
243 | |
244 | $c->_load_session |
245 | if ( $c->_sessionid && !$c->_session ); # must verify session data |
246 | |
247 | return $c->_sessionid; |
0974ac06 |
248 | } |
249 | |
250 | sub validate_session_id { |
4207ce8d |
251 | my ( $c, $sid ) = @_; |
0974ac06 |
252 | |
4207ce8d |
253 | $sid and $sid =~ /^[a-f\d]+$/i; |
0974ac06 |
254 | } |
255 | |
9e447f9d |
256 | sub session { |
9a9252c2 |
257 | my $c = shift; |
9e447f9d |
258 | |
29d15411 |
259 | $c->_session || $c->_load_session || do { |
78476ce0 |
260 | $c->create_session_id; |
9e447f9d |
261 | |
29d15411 |
262 | $c->initialize_session_data; |
4207ce8d |
263 | }; |
9e447f9d |
264 | } |
265 | |
873f7011 |
266 | sub flash { |
267 | my $c = shift; |
78476ce0 |
268 | $c->_flash || $c->_load_flash || do { |
269 | $c->create_session_id; |
270 | $c->_flash( {} ); |
4207ce8d |
271 | } |
873f7011 |
272 | } |
273 | |
b7acf64e |
274 | sub session_expire_key { |
275 | my ( $c, %keys ) = @_; |
276 | |
277 | my $now = time; |
4207ce8d |
278 | @{ $c->session->{__expire_keys} }{ keys %keys } = |
279 | map { $now + $_ } values %keys; |
b7acf64e |
280 | } |
281 | |
9e447f9d |
282 | sub initialize_session_data { |
9a9252c2 |
283 | my $c = shift; |
9e447f9d |
284 | |
9a9252c2 |
285 | my $now = time; |
9e447f9d |
286 | |
4207ce8d |
287 | return $c->_session( |
288 | { |
289 | __created => $now, |
290 | __updated => $now, |
291 | |
292 | ( |
293 | $c->config->{session}{verify_address} |
294 | ? ( __address => $c->request->address ) |
295 | : () |
296 | ), |
297 | } |
298 | ); |
9e447f9d |
299 | } |
300 | |
9e447f9d |
301 | sub generate_session_id { |
302 | my $c = shift; |
303 | |
304 | my $digest = $c->_find_digest(); |
305 | $digest->add( $c->session_hash_seed() ); |
306 | return $digest->hexdigest; |
307 | } |
308 | |
78476ce0 |
309 | sub create_session_id { |
310 | my $c = shift; |
311 | |
312 | if ( !$c->_sessionid ) { |
313 | my $sid = $c->generate_session_id; |
314 | |
315 | $c->log->debug(qq/Created session "$sid"/) if $c->debug; |
316 | |
317 | $c->sessionid($sid); |
318 | } |
319 | } |
320 | |
9e447f9d |
321 | my $counter; |
9a9252c2 |
322 | |
9e447f9d |
323 | sub session_hash_seed { |
9a9252c2 |
324 | my $c = shift; |
325 | |
326 | return join( "", ++$counter, time, rand, $$, {}, overload::StrVal($c), ); |
9e447f9d |
327 | } |
328 | |
329 | my $usable; |
9a9252c2 |
330 | |
9e447f9d |
331 | sub _find_digest () { |
9a9252c2 |
332 | unless ($usable) { |
d44bc687 |
333 | foreach my $alg (qw/SHA-1 SHA-256 MD5/) { |
4207ce8d |
334 | if ( eval { Digest->new($alg) } ) { |
5faaa4b0 |
335 | $usable = $alg; |
336 | last; |
337 | } |
7d139eeb |
338 | } |
4207ce8d |
339 | Catalyst::Exception->throw( |
9a9252c2 |
340 | "Could not find a suitable Digest module. Please install " |
4207ce8d |
341 | . "Digest::SHA1, Digest::SHA, or Digest::MD5" ) |
342 | unless $usable; |
9a9252c2 |
343 | } |
9e447f9d |
344 | |
345 | return Digest->new($usable); |
346 | } |
347 | |
99b2191e |
348 | sub dump_these { |
349 | my $c = shift; |
350 | |
351 | ( |
352 | $c->NEXT::dump_these(), |
353 | |
354 | $c->sessionid |
355 | ? ( [ "Session ID" => $c->sessionid ], [ Session => $c->session ], ) |
356 | : () |
357 | ); |
358 | } |
359 | |
9e447f9d |
360 | __PACKAGE__; |
361 | |
362 | __END__ |
363 | |
364 | =pod |
365 | |
366 | =head1 NAME |
367 | |
368 | Catalyst::Plugin::Session - Generic Session plugin - ties together server side |
fb1a4ac3 |
369 | storage and client side state required to maintain session data. |
9e447f9d |
370 | |
371 | =head1 SYNOPSIS |
372 | |
8f0b4c16 |
373 | # To get sessions to "just work", all you need to do is use these plugins: |
374 | |
375 | use Catalyst qw/ |
376 | Session |
377 | Session::Store::FastMmap |
378 | Session::State::Cookie |
379 | /; |
380 | |
381 | # you can replace Store::FastMmap with Store::File - both have sensible |
382 | # default configurations (see their docs for details) |
383 | |
384 | # more complicated backends are available for other scenarios (DBI storage, |
385 | # etc) |
386 | |
387 | |
388 | # after you've loaded the plugins you can save session data |
389 | # For example, if you are writing a shopping cart, it could be implemented |
390 | # like this: |
9e447f9d |
391 | |
229a5b53 |
392 | sub add_item : Local { |
393 | my ( $self, $c ) = @_; |
394 | |
395 | my $item_id = $c->req->param("item"); |
396 | |
8f0b4c16 |
397 | # $c->session is a hash ref, a bit like $c->stash |
398 | # the difference is that it' preserved across requests |
229a5b53 |
399 | |
400 | push @{ $c->session->{items} }, $item_id; |
401 | |
402 | $c->forward("MyView"); |
403 | } |
404 | |
405 | sub display_items : Local { |
406 | my ( $self, $c ) = @_; |
407 | |
408 | # values in $c->session are restored |
409 | $c->stash->{items_to_display} = |
8f0b4c16 |
410 | [ map { MyModel->retrieve($_) } @{ $c->session->{items} } ]; |
229a5b53 |
411 | |
412 | $c->forward("MyView"); |
413 | } |
414 | |
9e447f9d |
415 | =head1 DESCRIPTION |
416 | |
417 | The Session plugin is the base of two related parts of functionality required |
418 | for session management in web applications. |
419 | |
420 | The first part, the State, is getting the browser to repeat back a session key, |
421 | so that the web application can identify the client and logically string |
422 | several requests together into a session. |
423 | |
424 | The second part, the Store, deals with the actual storage of information about |
425 | the client. This data is stored so that the it may be revived for every request |
426 | made by the same client. |
427 | |
428 | This plugin links the two pieces together. |
429 | |
8f0b4c16 |
430 | =head1 RECCOMENDED BACKENDS |
431 | |
432 | =over 4 |
433 | |
434 | =item Session::State::Cookie |
435 | |
436 | The only really sane way to do state is using cookies. |
437 | |
438 | =item Session::Store::File |
439 | |
440 | A portable backend, based on Cache::File. |
441 | |
442 | =item Session::Store::FastMmap |
443 | |
444 | A fast and flexible backend, based on Cache::FastMmap. |
445 | |
446 | =back |
447 | |
9e447f9d |
448 | =head1 METHODS |
449 | |
450 | =over 4 |
451 | |
452 | =item sessionid |
453 | |
454 | An accessor for the session ID value. |
455 | |
456 | =item session |
457 | |
458 | Returns a hash reference that might contain unserialized values from previous |
459 | requests in the same session, and whose modified value will be saved for future |
460 | requests. |
461 | |
462 | This method will automatically create a new session and session ID if none |
463 | exists. |
464 | |
07e714d2 |
465 | =item flash |
466 | |
467 | This is like Ruby on Rails' flash data structure. Think of it as a stash that |
468 | lasts a single redirect, not only a forward. |
469 | |
470 | sub moose : Local { |
471 | my ( $self, $c ) = @_; |
472 | |
473 | $c->flash->{beans} = 10; |
474 | $c->response->redirect( $c->uri_for("foo") ); |
475 | } |
476 | |
477 | sub foo : Local { |
478 | my ( $self, $c ) = @_; |
479 | |
480 | my $value = $c->flash->{beans}; |
481 | |
482 | # ... |
483 | |
484 | $c->response->redirect( $c->uri_for("bar") ); |
485 | } |
486 | |
487 | sub bar : Local { |
488 | my ( $self, $c ) = @_; |
489 | |
490 | if ( exists $c->flash->{beans} ) { # false |
491 | |
492 | } |
493 | } |
494 | |
9e447f9d |
495 | =item session_delete_reason |
496 | |
497 | This accessor contains a string with the reason a session was deleted. Possible |
498 | values include: |
499 | |
500 | =over 4 |
501 | |
502 | =item * |
503 | |
504 | C<address mismatch> |
505 | |
506 | =item * |
507 | |
508 | C<session expired> |
509 | |
510 | =back |
511 | |
b7acf64e |
512 | =item session_expire_key $key, $ttl |
513 | |
514 | Mark a key to expire at a certain time (only useful when shorter than the |
515 | expiry time for the whole session). |
516 | |
517 | For example: |
518 | |
519 | __PACKAGE__->config->{session}{expires} = 1000000000000; # forever |
520 | |
521 | # later |
522 | |
523 | $c->session_expire_key( __user => 3600 ); |
524 | |
525 | Will make the session data survive, but the user will still be logged out after |
526 | an hour. |
527 | |
528 | Note that these values are not auto extended. |
529 | |
8f0b4c16 |
530 | =back |
531 | |
10c72079 |
532 | =head1 INTERNAL METHODS |
8f0b4c16 |
533 | |
534 | =over 4 |
535 | |
9e447f9d |
536 | =item setup |
537 | |
538 | This method is extended to also make calls to |
539 | C<check_session_plugin_requirements> and C<setup_session>. |
540 | |
541 | =item check_session_plugin_requirements |
542 | |
543 | This method ensures that a State and a Store plugin are also in use by the |
544 | application. |
545 | |
546 | =item setup_session |
547 | |
548 | This method populates C<< $c->config->{session} >> with the default values |
549 | listed in L</CONFIGURATION>. |
550 | |
551 | =item prepare_action |
552 | |
68fd02ae |
553 | This methoid is extended. |
554 | |
555 | It's only effect is if the (off by default) C<flash_to_stash> configuration |
556 | parameter is on - then it will copy the contents of the flash to the stash at |
557 | prepare time. |
9e447f9d |
558 | |
559 | =item finalize |
560 | |
561 | This method is extended and will extend the expiry time, as well as persist the |
562 | session data if a session exists. |
563 | |
564 | =item delete_session REASON |
565 | |
566 | This method is used to invalidate a session. It takes an optional parameter |
567 | which will be saved in C<session_delete_reason> if provided. |
568 | |
569 | =item initialize_session_data |
570 | |
571 | This method will initialize the internal structure of the session, and is |
572 | called by the C<session> method if appropriate. |
573 | |
68fd02ae |
574 | =item create_session_id |
575 | |
576 | Creates a new session id using C<generate_session_id> if there is no session ID |
577 | yet. |
578 | |
229a5b53 |
579 | =item generate_session_id |
580 | |
581 | This method will return a string that can be used as a session ID. It is |
582 | supposed to be a reasonably random string with enough bits to prevent |
583 | collision. It basically takes C<session_hash_seed> and hashes it using SHA-1, |
584 | MD5 or SHA-256, depending on the availibility of these modules. |
585 | |
586 | =item session_hash_seed |
587 | |
588 | This method is actually rather internal to generate_session_id, but should be |
589 | overridable in case you want to provide more random data. |
590 | |
591 | Currently it returns a concatenated string which contains: |
592 | |
0974ac06 |
593 | =item validate_session_id SID |
594 | |
595 | Make sure a session ID is of the right format. |
596 | |
597 | This currently ensures that the session ID string is any amount of case |
598 | insensitive hexadecimal characters. |
599 | |
229a5b53 |
600 | =over 4 |
601 | |
602 | =item * |
603 | |
604 | A counter |
605 | |
606 | =item * |
607 | |
608 | The current time |
609 | |
610 | =item * |
611 | |
612 | One value from C<rand>. |
613 | |
614 | =item * |
615 | |
616 | The stringified value of a newly allocated hash reference |
617 | |
618 | =item * |
619 | |
620 | The stringified value of the Catalyst context object |
621 | |
622 | =back |
623 | |
624 | In the hopes that those combined values are entropic enough for most uses. If |
625 | this is not the case you can replace C<session_hash_seed> with e.g. |
626 | |
627 | sub session_hash_seed { |
628 | open my $fh, "<", "/dev/random"; |
629 | read $fh, my $bytes, 20; |
630 | close $fh; |
631 | return $bytes; |
632 | } |
633 | |
634 | Or even more directly, replace C<generate_session_id>: |
635 | |
636 | sub generate_session_id { |
637 | open my $fh, "<", "/dev/random"; |
638 | read $fh, my $bytes, 20; |
639 | close $fh; |
640 | return unpack("H*", $bytes); |
641 | } |
642 | |
643 | Also have a look at L<Crypt::Random> and the various openssl bindings - these |
644 | modules provide APIs for cryptographically secure random data. |
645 | |
99b2191e |
646 | =item dump_these |
647 | |
648 | See L<Catalyst/dump_these> - ammends the session data structure to the list of |
649 | dumped objects if session ID is defined. |
650 | |
9e447f9d |
651 | =back |
652 | |
a92c8aeb |
653 | =head1 USING SESSIONS DURING PREPARE |
654 | |
655 | The earliest point in time at which you may use the session data is after |
656 | L<Catalyst::Plugin::Session>'s C<prepare_action> has finished. |
657 | |
658 | State plugins must set $c->session ID before C<prepare_action>, and during |
659 | C<prepare_action> L<Catalyst::Plugin::Session> will actually load the data from |
660 | the store. |
661 | |
662 | sub prepare_action { |
663 | my $c = shift; |
664 | |
665 | # don't touch $c->session yet! |
b1cd7d77 |
666 | |
a92c8aeb |
667 | $c->NEXT::prepare_action( @_ ); |
668 | |
669 | $c->session; # this is OK |
670 | $c->sessionid; # this is also OK |
671 | } |
672 | |
9e447f9d |
673 | =head1 CONFIGURATION |
674 | |
229a5b53 |
675 | $c->config->{session} = { |
676 | expires => 1234, |
677 | }; |
9e447f9d |
678 | |
679 | All configuation parameters are provided in a hash reference under the |
680 | C<session> key in the configuration hash. |
681 | |
682 | =over 4 |
683 | |
684 | =item expires |
685 | |
686 | The time-to-live of each session, expressed in seconds. Defaults to 7200 (two |
687 | hours). |
688 | |
689 | =item verify_address |
690 | |
8c7e922c |
691 | When true, C<<$c->request->address>> will be checked at prepare time. If it is |
692 | not the same as the address that initiated the session, the session is deleted. |
9e447f9d |
693 | |
68fd02ae |
694 | =item flash_to_stash |
695 | |
696 | This option makes it easier to have actions behave the same whether they were |
697 | forwarded to or redirected to. On prepare time it copies the contents of |
698 | C<flash> (if any) to the stash. |
699 | |
9e447f9d |
700 | =back |
701 | |
702 | =head1 SPECIAL KEYS |
703 | |
704 | The hash reference returned by C<< $c->session >> contains several keys which |
705 | are automatically set: |
706 | |
707 | =over 4 |
708 | |
709 | =item __expires |
710 | |
d44bc687 |
711 | This key no longer exists. This data is now saved elsewhere. |
9e447f9d |
712 | |
713 | =item __updated |
714 | |
d44bc687 |
715 | The last time a session was saved to the store. |
9e447f9d |
716 | |
717 | =item __created |
718 | |
719 | The time when the session was first created. |
720 | |
721 | =item __address |
722 | |
723 | The value of C<< $c->request->address >> at the time the session was created. |
8c7e922c |
724 | This value is only populated if C<verify_address> is true in the configuration. |
9e447f9d |
725 | |
726 | =back |
727 | |
c80e9f04 |
728 | =head1 CAVEATS |
729 | |
a552e4b5 |
730 | =head2 Round the Robin Proxies |
731 | |
c80e9f04 |
732 | C<verify_address> could make your site inaccessible to users who are behind |
733 | load balanced proxies. Some ISPs may give a different IP to each request by the |
734 | same client due to this type of proxying. If addresses are verified these |
735 | users' sessions cannot persist. |
736 | |
737 | To let these users access your site you can either disable address verification |
738 | as a whole, or provide a checkbox in the login dialog that tells the server |
739 | that it's OK for the address of the client to change. When the server sees that |
740 | this box is checked it should delete the C<__address> sepcial key from the |
741 | session hash when the hash is first created. |
742 | |
a552e4b5 |
743 | =head2 Race Conditions |
744 | |
745 | In this day and age where cleaning detergents and dutch football (not the |
746 | american kind) teams roam the plains in great numbers, requests may happen |
747 | simultaneously. This means that there is some risk of session data being |
748 | overwritten, like this: |
749 | |
750 | =over 4 |
751 | |
752 | =item 1. |
753 | |
754 | request a starts, request b starts, with the same session id |
755 | |
756 | =item 2. |
757 | |
758 | session data is loaded in request a |
759 | |
760 | =item 3. |
761 | |
762 | session data is loaded in request b |
763 | |
764 | =item 4. |
765 | |
766 | session data is changed in request a |
767 | |
768 | =item 5. |
769 | |
770 | request a finishes, session data is updated and written to store |
771 | |
772 | =item 6. |
773 | |
774 | request b finishes, session data is updated and written to store, overwriting |
775 | changes by request a |
776 | |
777 | =back |
778 | |
779 | If this is a concern in your application, a soon to be developed locking |
780 | solution is the only safe way to go. This will have a bigger overhead. |
781 | |
782 | For applications where any given user is only making one request at a time this |
783 | plugin should be safe enough. |
784 | |
d45028d6 |
785 | =head1 AUTHORS |
786 | |
baa9db9c |
787 | =over 4 |
788 | |
789 | =item Andy Grundman |
790 | |
791 | =item Christian Hansen |
792 | |
793 | =item Yuval Kogman, C<nothingmuch@woobling.org> (current maintainer) |
794 | |
795 | =item Sebastian Riedel |
796 | |
797 | =back |
798 | |
799 | And countless other contributers from #catalyst. Thanks guys! |
d45028d6 |
800 | |
cc40ae4b |
801 | =head1 COPYRIGHT & LICENSE |
d45028d6 |
802 | |
803 | Copyright (c) 2005 the aforementioned authors. All rights |
804 | reserved. This program is free software; you can redistribute |
805 | it and/or modify it under the same terms as Perl itself. |
806 | |
9e447f9d |
807 | =cut |
808 | |
809 | |