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