1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Ruby on Rails 2.2 Release Notes</title>
<!--[if lt IE 8]>
<script src="http://ie7-js.googlecode.com/svn/version/2.0(beta3)/IE8.js" type="text/javascript"></script>
<![endif]-->
<link href="stylesheets/base.css" media="screen" rel="Stylesheet" type="text/css" />
<link href="stylesheets/forms.css" media="screen" rel="Stylesheet" type="text/css" />
<link href="stylesheets/more.css" media="screen" rel="Stylesheet" type="text/css" />
<style type="text/css">
div#container {
max-width: 900px;
padding-bottom: 3em;
}
div#content {
margin-left: 200px;
}
div#container.notoc {
max-width: 600px;
}
.notoc div#content {
margin-left: 0;
}
pre {
line-height: 1.4em;
}
#content p tt {
background: #eeeeee;
border: solid 1px #cccccc;
padding: 3px;
}
dt {
font-weight: bold;
}
#content dt tt {
font-size: 10pt;
}
dd {
margin-left: 3em;
}
#content dt tt, #content pre tt {
background: none;
padding: 0;
border: 0;
}
#content .olist ol {
margin-left: 2em;
}
#header {
position: relative;
max-width: 840px;
margin-left: auto;
margin-right: auto;
}
#header.notoc {
max-width: 580px;
}
#logo {
position: absolute;
left: 10px;
top: 10px;
width: 110px;
height: 140px;
}
div#header h1#site_title {
background: url('images/ruby_on_rails_by_mike_rundle2.gif') top left no-repeat;
position: absolute;
width: 392px;
height: 55px;
left: 145px;
top: 20px;
margin: 0;
padding: 0;
}
#site_title span {
display: none;
}
#site_title_tagline {
display: none;
}
ul#navMain {
position: absolute;
margin: 0;
padding: 0;
top: 97px;
left: 145px;
}
.left-floaty, .right-floaty {
padding: 15px;
}
.admonitionblock,
.tableblock {
margin-left: 1em;
margin-right: 1em;
margin-top: 0.25em;
margin-bottom: 1em;
}
.admonitionblock .icon {
padding-right: 8px;
}
.admonitionblock .content {
border: solid 1px #ffda78;
background: #fffebd;
padding: 10px;
padding-top: 8px;
padding-bottom: 8px;
}
.admonitionblock .title {
font-size: 140%;
margin-bottom: 0.5em;
}
.tableblock table {
border: solid 1px #aaaaff;
background: #f0f0ff;
}
.tableblock th {
background: #e0e0e0;
}
.tableblock th,
.tableblock td {
padding: 3px;
padding-left: 5px;
padding-right: 5px;
}
.sidebarblock {
margin-top: 0.25em;
margin: 1em;
border: solid 1px #ccccbb;
padding: 8px;
background: #ffffe0;
}
.sidebarblock .sidebar-title {
font-size: 140%;
font-weight: 600;
margin-bottom: 0.3em;
}
.sidebarblock .sidebar-content > .para:last-child > p {
margin-bottom: 0;
}
.sidebarblock .sidebar-title a {
text-decoration: none;
}
.sidebarblock .sidebar-title a:hover {
text-decoration: underline;
}
</style>
</head>
<body>
<div id="header" >
<div id="logo">
<a href="index.html" title="Ruby on Rails"><img src="images/rails_logo_remix.gif" alt="Rails" height="140" width="110" /></a>
</div>
<h1 id="site_title"><span>Ruby on Rails</span></h1>
<h2 id="site_title_tagline">Sustainable productivity for web-application development</h2>
<ul id="navMain">
<li class="first-child"><a href="http://www.rubyonrails.org/" title="Ruby on Rails" class="ruby_on_rails">Ruby on Rails</a></li>
<li><a class="manuals" href="index.html" title="Manuals Index">Guides Index</a></li>
</ul>
</div>
<div id="container">
<div id="sidebar">
<h2>Chapters</h2>
<ol>
<li>
<a href="#_infrastructure">Infrastructure</a>
<ul>
<li><a href="#_internationalization">Internationalization</a></li>
<li><a href="#_compatibility_with_ruby_1_9_and_jruby">Compatibility with Ruby 1.9 and JRuby</a></li>
</ul>
</li>
<li>
<a href="#_documentation">Documentation</a>
</li>
<li>
<a href="#_better_integration_with_http_out_of_the_box_etag_support">Better integration with HTTP : Out of the box ETag support</a>
</li>
<li>
<a href="#_thread_safety">Thread Safety</a>
</li>
<li>
<a href="#_active_record">Active Record</a>
<ul>
<li><a href="#_transactional_migrations">Transactional Migrations</a></li>
<li><a href="#_connection_pooling">Connection Pooling</a></li>
<li><a href="#_hashes_for_join_table_conditions">Hashes for Join Table Conditions</a></li>
<li><a href="#_new_dynamic_finders">New Dynamic Finders</a></li>
<li><a href="#_associations_respect_private_protected_scope">Associations Respect Private/Protected Scope</a></li>
<li><a href="#_other_activerecord_changes">Other ActiveRecord Changes</a></li>
</ul>
</li>
<li>
<a href="#_action_controller">Action Controller</a>
<ul>
<li><a href="#_shallow_route_nesting">Shallow Route Nesting</a></li>
<li><a href="#_method_arrays_for_member_or_collection_routes">Method Arrays for Member or Collection Routes</a></li>
<li><a href="#_resources_with_specific_actions">Resources With Specific Actions</a></li>
<li><a href="#_other_action_controller_changes">Other Action Controller Changes</a></li>
</ul>
</li>
<li>
<a href="#_action_view">Action View</a>
</li>
<li>
<a href="#_action_mailer">Action Mailer</a>
</li>
<li>
<a href="#_active_support">Active Support</a>
<ul>
<li><a href="#_memoization">Memoization</a></li>
<li><a href="#_tt_each_with_object_tt"><tt>each_with_object</tt></a></li>
<li><a href="#_delegates_with_prefixes">Delegates With Prefixes</a></li>
<li><a href="#_other_active_support_changes">Other Active Support Changes</a></li>
</ul>
</li>
<li>
<a href="#_railties">Railties</a>
<ul>
<li><a href="#_tt_config_gems_tt"><tt>config.gems</tt></a></li>
<li><a href="#_other_railties_changes">Other Railties Changes</a></li>
</ul>
</li>
<li>
<a href="#_deprecated">Deprecated</a>
</li>
<li>
<a href="#_credits">Credits</a>
</li>
</ol>
</div>
<div id="content">
<h1>Ruby on Rails 2.2 Release Notes</h1>
<div id="preamble">
<div class="sectionbody">
<div class="para"><p>Rails 2.2 delivers a number of new and improved features. This list covers the major upgrades, but doesn't include every little bug fix and change. If you want to see everything, check out the <a href="http://github.com/rails/rails/commits/master">list of commits</a> in the main Rails repository on GitHub.</p></div>
<div class="para"><p>Along with Rails, 2.2 marks the launch of the <a href="http://guides.rubyonrails.org/">Ruby on Rails Guides</a>, the first results of the ongoing <a href="http://hackfest.rubyonrails.org/guide">Rails Guides hackfest</a>. This site will deliver high-quality documentation of the major features of Rails.</p></div>
</div>
</div>
<h2 id="_infrastructure">1. Infrastructure</h2>
<div class="sectionbody">
<div class="para"><p>Rails 2.2 is a significant release for the infrastructure that keeps Rails humming along and connected to the rest of the world.</p></div>
<h3 id="_internationalization">1.1. Internationalization</h3>
<div class="para"><p>Rails 2.2 supplies an easy system for internationalization (or i18n, for those of you tired of typing).</p></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributors: Rails i18 Team
</p>
</li>
<li>
<p>
More information :
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://rails-i18n.org">Official Rails i18 website</a>
</p>
</li>
<li>
<p>
<a href="http://www.artweb-design.de/2008/7/18/finally-ruby-on-rails-gets-internationalized">Finally. Ruby on Rails gets internationalized</a>
</p>
</li>
<li>
<p>
<a href="http://i18n-demo.phusion.nl">Localizing Rails : Demo application</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
<h3 id="_compatibility_with_ruby_1_9_and_jruby">1.2. Compatibility with Ruby 1.9 and JRuby</h3>
<div class="para"><p>Along with thread safety, a lot of work has been done to make Rails work well with JRuby and the upcoming Ruby 1.9. With Ruby 1.9 being a moving target, running edge Rails on edge Ruby is still a hit-or-miss proposition, but Rails is ready to make the transition to Ruby 1.9 when the latter is released.</p></div>
</div>
<h2 id="_documentation">2. Documentation</h2>
<div class="sectionbody">
<div class="para"><p>The internal documentation of Rails, in the form of code comments, has been improved in numerous places. In addition, the <a href="http://guides.rubyonrails.org/">Ruby on Rails Guides</a> project is the definitive source for information on major Rails components. In its first official release, the Guides page includes:</p></div>
<div class="ilist"><ul>
<li>
<p>
<a href="http://guides.rubyonrails.org/getting_started_with_rails.html">Getting Started with Rails</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/migrations.html">Rails Database Migrations</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/association_basics.html">Active Record Associations</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/finders.html">Active Record Finders</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/layouts_and_rendering.html">Layouts and Rendering in Rails</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/form_helpers.html">Action View Form Helpers</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/routing_outside_in.html">Rails Routing from the Outside In</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/actioncontroller_basics.html">Basics of Action Controller</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/caching_with_rails.html">Rails Caching</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/testing_rails_applications.html">Testing Rails Applications</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/security.html">Securing Rails Applications</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/debugging_rails_applications.html">Debugging Rails Applications</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/benchmarking_and_profiling.html">Benchmarking and Profiling Rails Applications</a>
</p>
</li>
<li>
<p>
<a href="http://guides.rubyonrails.org/creating_plugins.html">The Basics of Creating Rails Plugins</a>
</p>
</li>
</ul></div>
<div class="para"><p>All told, the Guides provide tens of thousands of words of guidance for beginning and intermediate Rails developers.</p></div>
<div class="para"><p>If you want to generate these guides locally, inside your application:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>rake doc<span style="color: #990000">:</span>guides
</tt></pre></div></div>
<div class="para"><p>This will put the guides inside <tt>RAILS_ROOT/doc/guides</tt> and you may start surfing straight away by opening <tt>RAILS_ROOT/doc/guides/index.html</tt> in your favourite browser.</p></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributors: <a href="http://guides.rails.info/authors.html">Rails Documentation Team</a>
</p>
</li>
<li>
<p>
Major contributions from <a href="http://advogato.org/person/fxn/diary.html">Xavier Noria</a> and <a href="http://izumi.plan99.net/blog/">Hongli Lai</a>.
</p>
</li>
<li>
<p>
More information:
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://hackfest.rubyonrails.org/guide">Rails Guides hackfest</a>
</p>
</li>
<li>
<p>
<a href="http://weblog.rubyonrails.org/2008/5/2/help-improve-rails-documentation-on-git-branch">Help improve Rails documentation on Git branch</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
</div>
<h2 id="_better_integration_with_http_out_of_the_box_etag_support">3. Better integration with HTTP : Out of the box ETag support</h2>
<div class="sectionbody">
<div class="para"><p>Supporting the etag and last modified timestamp in HTTP headers means that Rails can now send back an empty response if it gets a request for a resource that hasn't been modified lately. This allows you to check whether a response needs to be sent at all.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> ArticlesController <span style="color: #990000"><</span> ApplicationController
<span style="font-weight: bold"><span style="color: #0000FF">def</span></span> show_with_respond_to_block
<span style="color: #009900">@article</span> <span style="color: #990000">=</span> Article<span style="color: #990000">.</span>find<span style="color: #990000">(</span>params<span style="color: #990000">[:</span>id<span style="color: #990000">])</span>
<span style="font-style: italic"><span style="color: #9A1900"># If the request sends headers that differs from the options provided to stale?, then</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># the request is indeed stale and the respond_to block is triggered (and the options</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># to the stale? call is set on the response).</span></span>
<span style="font-style: italic"><span style="color: #9A1900">#</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># If the request headers match, then the request is fresh and the respond_to block is</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># not triggered. Instead the default render will occur, which will check the last-modified</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># and etag headers and conclude that it only needs to send a "304 Not Modified" instead</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># of rendering the template.</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">if</span></span> stale?<span style="color: #990000">(:</span>last_modified <span style="color: #990000">=></span> <span style="color: #009900">@article</span><span style="color: #990000">.</span>published_at<span style="color: #990000">.</span>utc<span style="color: #990000">,</span> <span style="color: #990000">:</span>etag <span style="color: #990000">=></span> <span style="color: #009900">@article</span><span style="color: #990000">)</span>
respond_to <span style="font-weight: bold"><span style="color: #0000FF">do</span></span> <span style="color: #990000">|</span>wants<span style="color: #990000">|</span>
<span style="font-style: italic"><span style="color: #9A1900"># normal response processing</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">def</span></span> show_with_implied_render
<span style="color: #009900">@article</span> <span style="color: #990000">=</span> Article<span style="color: #990000">.</span>find<span style="color: #990000">(</span>params<span style="color: #990000">[:</span>id<span style="color: #990000">])</span>
<span style="font-style: italic"><span style="color: #9A1900"># Sets the response headers and checks them against the request, if the request is stale</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># (i.e. no match of either etag or last-modified), then the default render of the template happens.</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># If the request is fresh, then the default render will return a "304 Not Modified"</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># instead of rendering the template.</span></span>
fresh_when<span style="color: #990000">(:</span>last_modified <span style="color: #990000">=></span> <span style="color: #009900">@article</span><span style="color: #990000">.</span>published_at<span style="color: #990000">.</span>utc<span style="color: #990000">,</span> <span style="color: #990000">:</span>etag <span style="color: #990000">=></span> <span style="color: #009900">@article</span><span style="color: #990000">)</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
</tt></pre></div></div>
</div>
<h2 id="_thread_safety">4. Thread Safety</h2>
<div class="sectionbody">
<div class="para"><p>The work done to make Rails thread-safe is rolling out in Rails 2.2. Depending on your web server infrastructure, this means you can handle more requests with fewer copies of Rails in memory, leading to better server performance and higher utilization of multiple cores.</p></div>
<div class="para"><p>To enable multithreaded dispatching in production mode of your application, add the following line in your <tt>config/environments/production.rb</tt>:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>config<span style="color: #990000">.</span>threadsafe!
</tt></pre></div></div>
<div class="ilist"><ul>
<li>
<p>
More information :
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://m.onkey.org/2008/10/23/thread-safety-for-your-rails">Thread safety for your Rails</a>
</p>
</li>
<li>
<p>
<a href="http://weblog.rubyonrails.org/2008/8/16/josh-peek-officially-joins-the-rails-core">Thread safety project announcement</a>
</p>
</li>
<li>
<p>
<a href="http://blog.headius.com/2008/08/qa-what-thread-safe-rails-means.html">Q/A: What Thread-safe Rails Means</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
</div>
<h2 id="_active_record">5. Active Record</h2>
<div class="sectionbody">
<div class="para"><p>There are two big additions to talk about here: transactional migrations and pooled database transactions. There's also a new (and cleaner) syntax for join table conditions, as well as a number of smaller improvements.</p></div>
<h3 id="_transactional_migrations">5.1. Transactional Migrations</h3>
<div class="para"><p>Historically, multiple-step Rails migrations have been a source of trouble. If something went wrong during a migration, everything before the error changed the database and everything after the error wasn't applied. Also, the migration version was stored as having been executed, which means that it couldn't be simply rerun by <tt>rake db:migrate:redo</tt> after you fix the problem. Transactional migrations change this by wrapping migration steps in a DDL transaction, so that if any of them fail, the entire migration is undone. In Rails 2.2, transactional migrations are supported on PostgreSQL out of the box. The code is extensible to other database types in the future - and IBM has already extended it to support the DB2 adapter.</p></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: <a href="http://adam.blog.heroku.com/">Adam Wiggins</a>
</p>
</li>
<li>
<p>
More information:
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://adam.blog.heroku.com/past/2008/9/3/ddl_transactions/">DDL Transactions</a>
</p>
</li>
<li>
<p>
<a href="http://db2onrails.com/2008/11/08/a-major-milestone-for-db2-on-rails/">A major milestone for DB2 on Rails</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
<h3 id="_connection_pooling">5.2. Connection Pooling</h3>
<div class="para"><p>Connection pooling lets Rails distribute database requests across a pool of database connections that will grow to a maximum size (by default 5, but you can add a <tt>pool</tt> key to your <tt>database.yml</tt> to adjust this). This helps remove bottlenecks in applications that support many concurrent users. There's also a <tt>wait_timeout</tt> that defaults to 5 seconds before giving up. <tt>ActiveRecord::Base.connection_pool</tt> gives you direct access to the pool if you need it.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>development<span style="color: #990000">:</span>
adapter<span style="color: #990000">:</span> mysql
username<span style="color: #990000">:</span> root
database<span style="color: #990000">:</span> sample_development
pool<span style="color: #990000">:</span> <span style="color: #993399">10</span>
wait_timeout<span style="color: #990000">:</span> <span style="color: #993399">10</span>
</tt></pre></div></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: <a href="http://blog.nicksieger.com/">Nick Sieger</a>
</p>
</li>
<li>
<p>
More information:
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-connection-pools">What's New in Edge Rails: Connection Pools</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
<h3 id="_hashes_for_join_table_conditions">5.3. Hashes for Join Table Conditions</h3>
<div class="para"><p>You can now specify conditions on join tables using a hash. This is a big help if you need to query across complex joins.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Photo <span style="color: #990000"><</span> ActiveRecord<span style="color: #990000">::</span>Base
belongs_to <span style="color: #990000">:</span>product
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Product <span style="color: #990000"><</span> ActiveRecord<span style="color: #990000">::</span>Base
has_many <span style="color: #990000">:</span>photos
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-style: italic"><span style="color: #9A1900"># Get all products with copyright-free photos:</span></span>
Product<span style="color: #990000">.</span>all<span style="color: #990000">(:</span>joins <span style="color: #990000">=></span> <span style="color: #990000">:</span>photos<span style="color: #990000">,</span> <span style="color: #990000">:</span>conditions <span style="color: #990000">=></span> <span style="color: #FF0000">{</span> <span style="color: #990000">:</span>photos <span style="color: #990000">=></span> <span style="color: #FF0000">{</span> <span style="color: #990000">:</span>copyright <span style="color: #990000">=></span> <span style="font-weight: bold"><span style="color: #0000FF">false</span></span> <span style="color: #FF0000">}}</span><span style="color: #990000">)</span>
</tt></pre></div></div>
<div class="ilist"><ul>
<li>
<p>
More information:
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://ryandaigle.com/articles/2008/7/7/what-s-new-in-edge-rails-easy-join-table-conditions">What's New in Edge Rails: Easy Join Table Conditions</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
<h3 id="_new_dynamic_finders">5.4. New Dynamic Finders</h3>
<div class="para"><p>Two new sets of methods have been added to Active Record's dynamic finders family.</p></div>
<h4 id="_tt_find_last_by_lt_attribute_gt_tt">5.4.1. <tt>find_last_by_<attribute></tt></h4>
<div class="para"><p>The <tt>find_last_by_<attribute></tt> method is equivalent to <tt>Model.last(:conditions ⇒ {:attribute ⇒ value})</tt></p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-style: italic"><span style="color: #9A1900"># Get the last user who signed up from London</span></span>
User<span style="color: #990000">.</span>find_last_by_city<span style="color: #990000">(</span><span style="color: #FF0000">'London'</span><span style="color: #990000">)</span>
</tt></pre></div></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: <a href="http://www.workingwithrails.com/person/9147-emilio-tagua">Emilio Tagua</a>
</p>
</li>
</ul></div>
<h4 id="_tt_find_by_lt_attribute_gt_tt">5.4.2. <tt>find_by_<attribute>!</tt></h4>
<div class="para"><p>The new bang! version of <tt>find_by_<attribute>!</tt> is equivalent to <tt>Model.first(:conditions ⇒ {:attribute ⇒ value}) || raise ActiveRecord::RecordNotFound</tt> Instead of returning <tt>nil</tt> if it can't find a matching record, this method will raise an exception if it cannot find a match.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-style: italic"><span style="color: #9A1900"># Raise ActiveRecord::RecordNotFound exception if 'Moby' hasn't signed up yet!</span></span>
User<span style="color: #990000">.</span>find_by_name!<span style="color: #990000">(</span><span style="color: #FF0000">'Moby'</span><span style="color: #990000">)</span>
</tt></pre></div></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: <a href="http://blog.hasmanythrough.com">Josh Susser</a>
</p>
</li>
</ul></div>
<h3 id="_associations_respect_private_protected_scope">5.5. Associations Respect Private/Protected Scope</h3>
<div class="para"><p>Active Record association proxies now respect the scope of methods on the proxied object. Previously (given User has_one :account) <tt>@user.account.private_method</tt> would call the private method on the associated Account object. That fails in Rails 2.2; if you need this functionality, you should use <tt>@user.account.send(:private_method)</tt> (or make the method public instead of private or protected). Please note that if you're overriding <tt>method_missing</tt>, you should also override <tt>respond_to</tt> to match the behavior in order for associations to function normally.</p></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: Adam Milligan
</p>
</li>
<li>
<p>
More information:
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://afreshcup.com/2008/10/24/rails-22-change-private-methods-on-association-proxies-are-private/">Rails 2.2 Change: Private Methods on Association Proxies are Private</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
<h3 id="_other_activerecord_changes">5.6. Other ActiveRecord Changes</h3>
<div class="ilist"><ul>
<li>
<p>
<tt>rake db:migrate:redo</tt> now accepts an optional VERSION to target that specific migration to redo
</p>
</li>
<li>
<p>
Set <tt>config.active_record.timestamped_migrations = false</tt> to have migrations with numeric prefix instead of UTC timestamp.
</p>
</li>
<li>
<p>
Counter cache columns (for associations declared with <tt>:counter_cache ⇒ true</tt>) do not need to be initialized to zero any longer.
</p>
</li>
<li>
<p>
<tt>ActiveRecord::Base.human_name</tt> for an internationalization-aware humane translation of model names
</p>
</li>
</ul></div>
</div>
<h2 id="_action_controller">6. Action Controller</h2>
<div class="sectionbody">
<div class="para"><p>On the controller side, there are several changes that will help tidy up your routes. There are also some internal changes in the routing engine to lower memory usage on complex applications.</p></div>
<h3 id="_shallow_route_nesting">6.1. Shallow Route Nesting</h3>
<div class="para"><p>Shallow route nesting provides a solution to the well-known difficulty of using deeply-nested resources. With shallow nesting, you need only supply enough information to uniquely identify the resource that you want to work with.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>map<span style="color: #990000">.</span>resources <span style="color: #990000">:</span>publishers<span style="color: #990000">,</span> <span style="color: #990000">:</span>shallow <span style="color: #990000">=></span> <span style="font-weight: bold"><span style="color: #0000FF">true</span></span> <span style="font-weight: bold"><span style="color: #0000FF">do</span></span> <span style="color: #990000">|</span>publisher<span style="color: #990000">|</span>
publisher<span style="color: #990000">.</span>resources <span style="color: #990000">:</span>magazines <span style="font-weight: bold"><span style="color: #0000FF">do</span></span> <span style="color: #990000">|</span>magazine<span style="color: #990000">|</span>
magazine<span style="color: #990000">.</span>resources <span style="color: #990000">:</span>photos
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
</tt></pre></div></div>
<div class="para"><p>This will enable recognition of (among others) these routes:</p></div>
<div class="listingblock">
<div class="content">
<pre><tt>/publishers/1 ==> publisher_path(1)
/publishers/1/magazines ==> publisher_magazines_path(1)
/magazines/2 ==> magazine_path(2)
/magazines/2/photos ==> magazines_photos_path(2)
/photos/3 ==> photo_path(3)</tt></pre>
</div></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: <a href="http://www.unwwwired.net/">S. Brent Faulkner</a>
</p>
</li>
<li>
<p>
More information:
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://guides.rails.info/routing/routing_outside_in.html#_nested_resources">Rails Routing from the Outside In</a>
</p>
</li>
<li>
<p>
<a href="http://ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-shallow-routes">What's New in Edge Rails: Shallow Routes</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
<h3 id="_method_arrays_for_member_or_collection_routes">6.2. Method Arrays for Member or Collection Routes</h3>
<div class="para"><p>You can now supply an array of methods for new member or collection routes. This removes the annoyance of having to define a route as accepting any verb as soon as you need it to handle more than one. With Rails 2.2, this is a legitimate route declaration:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>map<span style="color: #990000">.</span>resources <span style="color: #990000">:</span>photos<span style="color: #990000">,</span> <span style="color: #990000">:</span>collection <span style="color: #990000">=></span> <span style="color: #FF0000">{</span> <span style="color: #990000">:</span>search <span style="color: #990000">=></span> <span style="color: #990000">[:</span>get<span style="color: #990000">,</span> <span style="color: #990000">:</span>post<span style="color: #990000">]</span> <span style="color: #FF0000">}</span>
</tt></pre></div></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: <a href="http://brennandunn.com/">Brennan Dunn</a>
</p>
</li>
</ul></div>
<h3 id="_resources_with_specific_actions">6.3. Resources With Specific Actions</h3>
<div class="para"><p>By default, when you use <tt>map.resources</tt> to create a route, Rails generates routes for seven default actions (index, show, create, new, edit, update, and destroy). But each of these routes takes up memory in your application, and causes Rails to generate additional routing logic. Now you can use the <tt>:only</tt> and <tt>:except</tt> options to fine-tune the routes that Rails will generate for resources. You can supply a single action, an array of actions, or the special <tt>:all</tt> or <tt>:none</tt> options. These options are inherited by nested resources.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>map<span style="color: #990000">.</span>resources <span style="color: #990000">:</span>photos<span style="color: #990000">,</span> <span style="color: #990000">:</span>only <span style="color: #990000">=></span> <span style="color: #990000">[:</span>index<span style="color: #990000">,</span> <span style="color: #990000">:</span>show<span style="color: #990000">]</span>
map<span style="color: #990000">.</span>resources <span style="color: #990000">:</span>products<span style="color: #990000">,</span> <span style="color: #990000">:</span>except <span style="color: #990000">=></span> <span style="color: #990000">:</span>destroy
</tt></pre></div></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: <a href="http://experthuman.com/">Tom Stuart</a>
</p>
</li>
</ul></div>
<h3 id="_other_action_controller_changes">6.4. Other Action Controller Changes</h3>
<div class="ilist"><ul>
<li>
<p>
You can now easily <a href="http://m.onkey.org/2008/7/20/rescue-from-dispatching">show a custom error page</a> for exceptions raised while routing a request.
</p>
</li>
<li>
<p>
The HTTP Accept header is disabled by default now. You should prefer the use of formatted URLs (such as <tt>/customers/1.xml</tt>) to indicate the format that you want. If you need the Accept headers, you can turn them back on with <tt>config.action_controller.user_accept_header = true</tt>.
</p>
</li>
<li>
<p>
Benchmarking numbers are now reported in milliseconds rather than tiny fractions of seconds
</p>
</li>
<li>
<p>
Rails now supports HTTP-only cookies (and uses them for sessions), which help mitigate some cross-site scripting risks in newer browsers.
</p>
</li>
<li>
<p>
<tt>redirect_to</tt> now fully supports URI schemes (so, for example, you can redirect to a svn+ssh: URI).
</p>
</li>
<li>
<p>
<tt>render</tt> now supports a <tt>:js</tt> option to render plain vanilla javascript with the right mime type.
</p>
</li>
<li>
<p>
Request forgery protection has been tightened up to apply to HTML-formatted content requests only.
</p>
</li>
<li>
<p>
Polymorphic URLs behave more sensibly if a passed parameter is nil. For example, calling <tt>polymorphic_path([@project, @date, @area])</tt> with a nil date will give you <tt>project_area_path</tt>.
</p>
</li>
</ul></div>
</div>
<h2 id="_action_view">7. Action View</h2>
<div class="sectionbody">
<div class="ilist"><ul>
<li>
<p>
<tt>javascript_include_tag</tt> and <tt>stylesheet_link_tag</tt> support a new <tt>:recursive</tt> option to be used along with <tt>:all</tt>, so that you can load an entire tree of files with a single line of code.
</p>
</li>
<li>
<p>
The included Prototype javascript library has been upgraded to version 1.6.0.3.
</p>
</li>
<li>
<p>
<tt>RJS#page.reload</tt> to reload the browser's current location via javascript
</p>
</li>
<li>
<p>
The <tt>atom_feed</tt> helper now takes an <tt>:instruct</tt> option to let you insert XML processing instructions.
</p>
</li>
</ul></div>
</div>
<h2 id="_action_mailer">8. Action Mailer</h2>
<div class="sectionbody">
<div class="para"><p>Action Mailer now supports mailer layouts. You can make your HTML emails as pretty as your in-browser views by supplying an appropriately-named layout - for example, the <tt>CustomerMailer</tt> class expects to use <tt>layouts/customer_mailer.html.erb</tt>.</p></div>
<div class="ilist"><ul>
<li>
<p>
More information:
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-mailer-layouts">What's New in Edge Rails: Mailer Layouts</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
<div class="para"><p>Action Mailer now offers built-in support for GMail's SMTP servers, by turning on STARTTLS automatically. This requires Ruby 1.8.7 to be installed.</p></div>
</div>
<h2 id="_active_support">9. Active Support</h2>
<div class="sectionbody">
<div class="para"><p>Active Support now offers built-in memoization for Rails applications, the <tt>each_with_object</tt> method, prefix support on delegates, and various other new utility methods.</p></div>
<h3 id="_memoization">9.1. Memoization</h3>
<div class="para"><p>Memoization is a pattern of initializing a method once and then stashing its value away for repeat use. You've probably used this pattern in your own applications:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">def</span></span> full_name
<span style="color: #009900">@full_name</span> <span style="color: #990000">||=</span> <span style="color: #FF0000">"#{first_name} #{last_name}"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
</tt></pre></div></div>
<div class="para"><p>Memoization lets you handle this task in a declarative fashion:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>extend ActiveSupport<span style="color: #990000">::</span>Memoizable
<span style="font-weight: bold"><span style="color: #0000FF">def</span></span> full_name
<span style="color: #FF0000">"#{first_name} #{last_name}"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
memoize <span style="color: #990000">:</span>full_name
</tt></pre></div></div>
<div class="para"><p>Other features of memoization include <tt>unmemoize</tt>, <tt>unmemoize_all</tt>, and <tt>memoize_all</tt> to turn memoization on or off.</p></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: <a href="http://joshpeek.com/">Josh Peek</a>
</p>
</li>
<li>
<p>
More information:
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://ryandaigle.com/articles/2008/7/16/what-s-new-in-edge-rails-memoization">What's New in Edge Rails: Easy Memoization</a>
</p>
</li>
<li>
<p>
<a href="http://www.railway.at/articles/2008/09/20/a-guide-to-memoization">Memo-what? A Guide to Memoization</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
<h3 id="_tt_each_with_object_tt">9.2. <tt>each_with_object</tt></h3>
<div class="para"><p>The <tt>each_with_object</tt> method provides an alternative to <tt>inject</tt>, using a method backported from Ruby 1.9. It iterates over a collection, passing the current element and the memo into the block.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="color: #990000">%</span>w<span style="color: #990000">(</span>foo bar<span style="color: #990000">).</span>each_with_object<span style="color: #990000">(</span><span style="color: #FF0000">{}</span><span style="color: #990000">)</span> <span style="color: #FF0000">{</span> <span style="color: #990000">|</span>str<span style="color: #990000">,</span> hsh<span style="color: #990000">|</span> hsh<span style="color: #990000">[</span>str<span style="color: #990000">]</span> <span style="color: #990000">=</span> str<span style="color: #990000">.</span>upcase <span style="color: #FF0000">}</span> <span style="font-style: italic"><span style="color: #9A1900">#=> {'foo' => 'FOO', 'bar' => 'BAR'}</span></span>
</tt></pre></div></div>
<div class="para"><p>Lead Contributor: <a href="http://therealadam.com/">Adam Keys</a></p></div>
<h3 id="_delegates_with_prefixes">9.3. Delegates With Prefixes</h3>
<div class="para"><p>If you delegate behavior from one class to another, you can now specify a prefix that will be used to identify the delegated methods. For example:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Vendor <span style="color: #990000"><</span> ActiveRecord<span style="color: #990000">::</span>Base
has_one <span style="color: #990000">:</span>account
delegate <span style="color: #990000">:</span>email<span style="color: #990000">,</span> <span style="color: #990000">:</span>password<span style="color: #990000">,</span> <span style="color: #990000">:</span>to <span style="color: #990000">=></span> <span style="color: #990000">:</span>account<span style="color: #990000">,</span> <span style="color: #990000">:</span>prefix <span style="color: #990000">=></span> <span style="font-weight: bold"><span style="color: #0000FF">true</span></span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
</tt></pre></div></div>
<div class="para"><p>This will produce delegated methods <tt>vendor#account_email</tt> and <tt>vendor#account_password</tt>. You can also specify a custom prefix:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> Vendor <span style="color: #990000"><</span> ActiveRecord<span style="color: #990000">::</span>Base
has_one <span style="color: #990000">:</span>account
delegate <span style="color: #990000">:</span>email<span style="color: #990000">,</span> <span style="color: #990000">:</span>password<span style="color: #990000">,</span> <span style="color: #990000">:</span>to <span style="color: #990000">=></span> <span style="color: #990000">:</span>account<span style="color: #990000">,</span> <span style="color: #990000">:</span>prefix <span style="color: #990000">=></span> <span style="color: #990000">:</span>owner
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
</tt></pre></div></div>
<div class="para"><p>This will produce delegated methods <tt>vendor#owner_email</tt> and <tt>vendor#owner_password</tt>.</p></div>
<div class="para"><p>Lead Contributor: <a href="http://workingwithrails.com/person/5830-daniel-schierbeck">Daniel Schierbeck</a></p></div>
<h3 id="_other_active_support_changes">9.4. Other Active Support Changes</h3>
<div class="ilist"><ul>
<li>
<p>
Extensive updates to <tt>ActiveSupport::Multibyte</tt>, including Ruby 1.9 compatibility fixes.
</p>
</li>
<li>
<p>
The addition of <tt>ActiveSupport::Rescuable</tt> allows any class to mix in the <tt>rescue_from</tt> syntax.
</p>
</li>
<li>
<p>
<tt>past?</tt>, <tt>today?</tt> and <tt>future?</tt> for <tt>Date</tt> and <tt>Time</tt> classes to facilitate date/time comparisons.
</p>
</li>
<li>
<p>
<tt>Array#second</tt> through <tt>Array#tenth</tt> as aliases for <tt>Array#[1]</tt> through <tt>Array#[9]</tt>
</p>
</li>
<li>
<p>
<tt>Enumerable#many?</tt> to encapsulate <tt>collection.size > 1</tt>
</p>
</li>
<li>
<p>
<tt>Inflector#parameterize</tt> produces a URL-ready version of its input, for use in <tt>to_param</tt>.
</p>
</li>
<li>
<p>
<tt>Time#advance</tt> recognizes fractional days and weeks, so you can do <tt>1.7.weeks.ago</tt>, <tt>1.5.hours.since</tt>, and so on.
</p>
</li>
<li>
<p>
The included TzInfo library has been upgraded to version 0.3.11.
</p>
</li>
<li>
<p>
<tt>ActiveSuport::StringInquirer</tt> gives you a pretty way to test for equality in strings: <tt>ActiveSupport::StringInquirer.new("abc").abc? ⇒ true</tt>
</p>
</li>
</ul></div>
</div>
<h2 id="_railties">10. Railties</h2>
<div class="sectionbody">
<div class="para"><p>In Railties (the core code of Rails itself) the biggest changes are in the <tt>config.gems</tt> mechanism.</p></div>
<h3 id="_tt_config_gems_tt">10.1. <tt>config.gems</tt></h3>
<div class="para"><p>To avoid deployment issues and make Rails applications more self-contained, it's possible to place copies of all of the gems that your Rails application requires in <tt>/vendor/gems</tt>. This capability first appeared in Rails 2.1, but it's much more flexible and robust in Rails 2.2, handling complicated dependencies between gems. Gem management in Rails includes these commands:</p></div>
<div class="ilist"><ul>
<li>
<p>
<tt>config.gem <em>gem_name</em></tt> in your <tt>config/environment.rb</tt> file
</p>
</li>
<li>
<p>
<tt>rake gems</tt> to list all configured gems, as well as whether they (and their dependencies) are installed or frozen
</p>
</li>
<li>
<p>
<tt>rake gems:install</tt> to install missing gems to the computer
</p>
</li>
<li>
<p>
<tt>rake gems:unpack</tt> to place a copy of the required gems into <tt>/vendor/gems</tt>
</p>
</li>
<li>
<p>
<tt>rake gems:unpack:dependencies</tt> to get copies of the required gems and their dependencies into <tt>/vendor/gems</tt>
</p>
</li>
<li>
<p>
<tt>rake gems:build</tt> to build any missing native extensions
</p>
</li>
<li>
<p>
<tt>rake gems:refresh_specs</tt> to bring vendored gems created with Rails 2.1 into alignment with the Rails 2.2 way of storing them
</p>
</li>
</ul></div>
<div class="para"><p>You can unpack or install a single gem by specifying <tt>GEM=<em>gem_name</em></tt> on the command line.</p></div>
<div class="ilist"><ul>
<li>
<p>
Lead Contributor: <a href="http://github.com/al2o3cr">Matt Jones</a>
</p>
</li>
<li>
<p>
More information:
</p>
<div class="ilist"><ul>
<li>
<p>
<a href="http://ryandaigle.com/articles/2008/4/1/what-s-new-in-edge-rails-gem-dependencies">What's New in Edge Rails: Gem Dependencies</a>
</p>
</li>
<li>
<p>
<a href="http://afreshcup.com/2008/10/25/rails-212-and-22rc1-update-your-rubygems/">Rails 2.1.2 and 2.2RC1: Update Your RubyGems</a>
</p>
</li>
</ul></div>
</li>
</ul></div>
<h3 id="_other_railties_changes">10.2. Other Railties Changes</h3>
<div class="ilist"><ul>
<li>
<p>
If you're a fan of the <a href="http://code.macournoyer.com/thin/">Thin</a> web server, you'll be happy to know that <tt>script/server</tt> now supports Thin directly.
</p>
</li>
<li>
<p>
<tt>script/plugin install <plugin> -r <revision></tt> now works with git-based as well as svn-based plugins.
</p>
</li>
<li>
<p>
<tt>script/console</tt> now supports a <tt>—debugger</tt> option
</p>
</li>
<li>
<p>
Instructions for setting up a continuous integration server to build Rails itself are included in the Rails source
</p>
</li>
<li>
<p>
<tt>rake notes:custom ANNOTATION=MYFLAG</tt> lets you list out custom annotations.
</p>
</li>
<li>
<p>
Wrapped <tt>Rails.env</tt> in <tt>StringInquirer</tt> so you can do <tt>Rails.env.development?</tt>
</p>
</li>
<li>
<p>
To eliminate deprecation warnings and properly handle gem dependencies, Rails now requires rubygems 1.3.1 or higher.
</p>
</li>
</ul></div>
</div>
<h2 id="_deprecated">11. Deprecated</h2>
<div class="sectionbody">
<div class="para"><p>A few pieces of older code are deprecated in this release:</p></div>
<div class="ilist"><ul>
<li>
<p>
<tt>Rails::SecretKeyGenerator</tt> has been replaced by <tt>ActiveSupport::SecureRandom</tt>
</p>
</li>
<li>
<p>
<tt>render_component</tt> is deprecated. There's a <a href="http://github.com/rails/render_component/tree/master">render_components plugin</a> available if you need this functionality.
</p>
</li>
<li>
<p>
Implicit local assignments when rendering partials has been deprecated.
</p>
</li>
</ul></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 2.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">def</span></span> partial_with_implicit_local_assignment
<span style="color: #009900">@customer</span> <span style="color: #990000">=</span> Customer<span style="color: #990000">.</span>new<span style="color: #990000">(</span><span style="color: #FF0000">"Marcel"</span><span style="color: #990000">)</span>
render <span style="color: #990000">:</span>partial <span style="color: #990000">=></span> <span style="color: #FF0000">"customer"</span>
<span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
</tt></pre></div></div>
<div class="para"><p>Previously the above code made available a local variable called <tt>customer</tt> inside the partial <em>customer</em>. You should explicitly pass all the variables via :locals hash now.</p></div>
<div class="ilist"><ul>
<li>
<p>
<tt>country_select</tt> has been removed. See the <a href="http://www.rubyonrails.org/deprecation/list-of-countries">deprecation page</a> for more information and a plugin replacement.
</p>
</li>
<li>
<p>
<tt>ActiveRecord::Base.allow_concurrency</tt> no longer has any effect.
</p>
</li>
<li>
<p>
<tt>ActiveRecord::Errors.default_error_messages</tt> has been deprecated in favor of <tt>I18n.translate(<em>activerecord.errors.messages</em>)</tt>
</p>
</li>
<li>
<p>
The <tt>%s</tt> and <tt>%d</tt> interpolation syntax for internationalization is deprecated.
</p>
</li>
<li>
<p>
<tt>String#chars</tt> has been deprecated in favor of <tt>String#mb_chars</tt>.
</p>
</li>
<li>
<p>
Durations of fractional months or fractional years are deprecated. Use Ruby's core <tt>Date</tt> and <tt>Time</tt> class arithmetic instead.
</p>
</li>
</ul></div>
</div>
<h2 id="_credits">12. Credits</h2>
<div class="sectionbody">
<div class="para"><p>Release notes compiled by <a href="http://afreshcup.com">Mike Gunderloy</a></p></div>
</div>
</div>
</div>
</body>
</html>
|
