3 CGI::Ex::App - Anti-framework application framework.
9 -------- File: /cgi-bin/my_cgi --------
14 use base qw(CGI::Ex::App);
16 __PACKAGE__->navigate;
20 return \ "Hello World!";
23 Well, you should put your content in an external file...
25 -------- File: /cgi-bin/my_cgi --------
30 use base qw(CGI::Ex::App);
32 __PACKAGE__->navigate;
34 sub template_path { '/var/www/templates' }
37 -------- File: /var/www/templates/my_cgi/main.html --------
41 How about if we want to add substitutions...
43 -------- File: /cgi-bin/my_cgi --------
48 use base qw(CGI::Ex::App);
50 __PACKAGE__->navigate;
52 sub template_path { '/var/www/templates' }
58 date => sub { scalar localtime },
63 -------- File: /var/www/templates/my_cgi/main.html --------
65 [% greeting %] World! ([% date %])
68 How about a form with validation (inluding javascript validation)...
70 -------- File: /cgi-bin/my_cgi --------
75 use base qw(CGI::Ex::App);
77 __PACKAGE__->navigate;
79 sub template_path { '/var/www/templates' }
81 sub main_hash_swap { {date => sub { scalar localtime }} }
89 sub main_hash_validation {
94 compare1_error => 'Please enter a value less than 101',
96 compare2_error => 'Please enter a value greater than 0',
103 my $form = $self->form;
105 $self->add_to_form({was_correct => ($form->{'guess'} == 23)});
107 return 0; # indicate to show the page without trying to move along
111 -------- File: /var/www/templates/my_cgi/main.html --------
113 <h2>Hello World! ([% date %])</h2>
116 <b>Correct!</b> - The number was [% guess %].<br>
118 <b>Incorrect</b> - The number was not [% guess %].<br>
121 <form name="[% form_name %]" method="post">
123 Enter a number between 1 and 100: <input type="text" name="guess"><br>
124 <span id="guess_error" style="color:red">[% guess_error %]</span><br>
126 <input type="submit">
132 There are infinite possibilities. There is a longer "SYNOPSIS" after
133 the process flow discussion and more examples near the end of this
134 document. It is interesting to note that there have been no databases
135 so far. It is very, very difficult to find a single database
136 abstraction that fits every model. CGI::Ex::App is Controller/Viewer
137 that is somewhat Model agnostic and doesn't come with any default
138 database abstraction.
142 Fill in the blanks and get a ready made web application.
144 This module is somewhat similar in spirit to CGI::Application,
145 CGI::Path, and CGI::Builder and any other "CGI framework." As with
146 the others, CGI::Ex::App tries to do as much of the mundane things, in
147 a simple manner, without getting in the developer's way. However,
148 there are various design patterns for CGI applications that
149 CGI::Ex::App handles for you that the other frameworks require you to
150 bring in extra support. The entire CGI::Ex suite has been taylored to
151 work seamlessly together. Your mileage in building applications may
154 If you build applications that submit user information, validate it,
155 re-display it, fill in forms, or separate logic into separate modules,
156 then this module may be for you. If all you need is a dispatch
157 engine, then this still may be for you. If all you want is to look at
158 user passed information, then this may still be for you. If you like
159 writing bare metal code, this could still be for you. If you don't want
160 to write any code, this module will help - but you still need to
161 provide your key actions and html.
163 One of the great benefits of CGI::Ex::App vs. Catalyst or Rails style
164 frameworks is that the model of CGI::Ex::App can be much more abstract.
165 And models often are abstract.
167 =head1 DEFAULT PROCESS FLOW
169 The following pseudo-code describes the process flow
170 of the CGI::Ex::App framework. Several portions of the flow
171 are encapsulated in hooks which may be completely overridden to give
172 different flow. All of the default actions are shown. It may look
173 like a lot to follow, but if the process is broken down into the
174 discrete operations of step iteration, data validation, and template
175 printing the flow feels more natural.
179 The process starts off by calling ->navigate.
187 # dying errors will run the ->handle_error method
194 The nav_loop method will run as follows:
197 ->path (get the array of path steps)
198 # ->path_info_map_base (method - map ENV PATH_INFO to form)
199 # look in ->form for ->step_key
200 # make sure step is in ->valid_steps (if defined)
203 # navigation stops if true
205 foreach step of path {
207 ->require_auth (hook)
208 # exits nav_loop if true
211 # check ->allow_morph (hook)
212 # check ->allow_nested_morph
213 # ->morph_package (hook - get the package to bless into)
214 # ->fixup_after_morph if morph_package exists
215 # if no package is found, process continues in current file
217 ->path_info_map (hook - map PATH_INFO to form)
222 # only called if run_step returned false (page not printed)
223 ->next_step (hook) # find next step and add to path
224 ->set_ready_validate(0) (hook)
227 # only called if morph worked
228 # ->fixup_before_unmorph if blessed to current package
230 # exit loop if ->run_step returned true (page printed)
232 } end of foreach step
235 # navigation stops if true
238 ->insert_path (puts the default step into the path)
239 ->nav_loop (called again recursively)
243 =head2 run_step (hook)
245 For each step of the path the following methods will be run
246 during the run_step hook.
250 # skips this step if true and exit nav_loop
253 # skips this step if true and stays in nav_loop
255 ->prepare (hook - defaults to true)
257 ->info_complete (hook - ran if prepare was true)
258 ->ready_validate (hook)
259 ->validate_when_data (hook)
260 # returns false from info_complete if ! ready_validate
261 ->validate (hook - uses CGI::Ex::Validate to validate form info)
262 ->hash_validation (hook)
264 ->vob_path (defaults to template_path)
269 # returns true if validate is true or if nothing to validate
271 ->finalize (hook - defaults to true - ran if prepare and info_complete were true)
273 if ! ->prepare || ! ->info_complete || ! ->finalize {
281 # merge form, base, common, and fill into merged fill
282 # merge form, base, common, swap, and errors into merged swap
283 ->print (hook - passed current step, merged swap hash, and merged fill)
284 ->file_print (hook - uses base_dir_rel, name_module, name_step, ext_print)
285 ->swap_template (hook - processes the file with CGI::Ex::Template)
286 ->template_args (hook - passed to CGI::Ex::Template->new)
287 ->fill_template (hook - fills the any forms with CGI::Ex::Fill)
288 ->fill_args (hook - passed to CGI::Ex::Fill::fill)
289 ->print_out (hook - print headers and the content to STDOUT)
291 ->post_print (hook - used for anything after the print process)
293 # return true to exit from nav_loop
297 # exits nav_loop if true
301 It is important to learn the function and placement of each of the
302 hooks in the process flow in order to make the most of CGI::Ex::App.
303 It is enough to begin by learning a few common hooks - such as
304 hash_validation, hash_swap, and finalize, and then learn about other
305 hooks as needs arise. Sometimes, it is enough to simply override the
306 run_step hook and take care of processing the entire step yourself.
308 Because of the hook based system, and because CGI::Ex::App uses
309 sensible defaults, it is very easy to override a little or a lot which
310 ends up giving the developer a lot of flexibility.
312 Additionally, it should be possible to use CGI::Ex::App with the other
313 frameworks such as CGI::Application or CGI::Prototype. For these you
314 could simple let each "runmode" call the run_step hook of CGI::Ex::App
315 and you will instantly get all of the common process flow for free.
317 =head1 MAPPING URI TO STEP
319 The default out of the box configuration will map URIs to steps as follows:
321 # Assuming /cgi-bin/my_app is the program being run
326 WHY: No other information is passed. The path method is
327 called which eventually calls ->default_step which
330 URI: /cgi-bin/my_app?foo=bar
333 WHY: Same as previous example except that QUERY_STRING
334 information was passed and placed in form.
336 URI: /cgi-bin/my_app?step=my_step
338 FORM: {step => "my_step"}
339 WHY: The path method is called which looks in $self->form
340 for the key ->step_key (which defaults to "step").
342 URI: /cgi-bin/my_app?step=my_step&foo=bar
344 FORM: {foo => "bar", step => "my_step"}
345 WHY: Same as before but another parameter was passed.
347 URI: /cgi-bin/my_app/my_step
349 FORM: {step => "my_step"}
350 WHY: The path method is called which called path_info_map_base
351 which matched $ENV{'PATH_INFO'} using the default regex
352 of qr{^/(\w+)$} and place the result in
353 $self->form->{$self->step_key}. Path then looks in
354 $self->form->{$self->step_key} for the initial step. See
355 the path_info_map_base method for more information.
357 URI: /cgi-bin/my_app/my_step?foo=bar
359 FORM: {foo => "bar", step => "my_step"}
360 WHY: Same as before but other parameters were passed.
362 URI: /cgi-bin/my_app/my_step?step=other_step
364 FORM: {step => "other_step"}
365 WHY: The same procedure took place, but when the PATH_INFO
366 string was matched, the form key "step" already existed
367 and was not replaced by the value from PATH_INFO.
369 The remaining examples in this section are based on the assumption
370 that the following method is installed in your script.
372 sub my_step_path_info_map {
374 [qr{^/\w+/(\w+)/(\d+)$}, 'foo', 'id'],
375 [qr{^/\w+/(\w+)$}, 'foo'],
376 [qr{^/\w+/(.+)$}, 'anything_else'],
380 URI: /cgi-bin/my_app/my_step/bar
383 WHY: The step was matched as in previous examples using
384 path_info_map_base. However, the form key "foo"
385 was set to "bar" because the second regex returned
386 by the path_info_map hook matched the PATH_INFO string
387 and the corresponding matched value was placed into
388 the form using the keys specified following the regex.
390 URI: /cgi-bin/my_app/my_step/bar/1234
392 FORM: {foo => "bar", id => "1234"}
393 WHY: Same as the previous example, except that the first
394 regex matched the string. The first regex had two
395 match groups and two form keys specified. Note that
396 it is important to order your match regexes in the
397 order that will match the most data. The third regex
398 would also match this PATH_INFO.
400 URI: /cgi-bin/my_app/my_step/some/other/type/of/data
402 FORM: {anything_else => 'some/other/type/of/data'}
403 WHY: Same as the previous example, except that the third
406 URI: /cgi-bin/my_app/my_step/bar?bling=blang
408 FORM: {foo => "bar", bling => "blang"}
409 WHY: Same as the first sample, but additional QUERY_STRING
410 information was passed.
412 URI: /cgi-bin/my_app/my_step/one%20two?bar=three%20four
414 FORM: {anything_else => "one two", bar => "three four"}
415 WHY: The third path_info_map regex matched. Note that the
416 %20 in bar was unescaped by CGI::param, but the %20
417 in anything_else was unescaped by Apache. If you are
418 not using Apache, this behavior may vary. CGI::Ex::App
419 doesn't decode parameters mapped from PATH_INFO.
421 See the path method for more information about finding the initial step
424 The form method calls CGI::Ex::form which uses CGI::param to retrieve
425 GET and POST parameters. See the form method for more information on
426 how GET and POST parameters are parsed.
428 See the path_info_map_base method, and path_info_map hook for more information
429 on how the path_info maps function.
431 Using the following code is very useful for determing what hooks have
434 use CGI::Ex::Dump qw(debug);
438 debug $self->dump_history, $self->form;
441 =head1 ADDING DATA VALIDATION TO A STEP
443 CGI::Ex::App uses CGI::Ex::Validate for its data validation. See CGI::Ex::Validate
444 for more information about the many ways you can validate your data.
446 The default hash_validation hook returns an empty hashref. This means that passed
447 in data is all valid and the script will automatically call the step's finalize method.
449 The following shows how to add some contrived validation to a step called "my_step".
451 sub my_step_hash_validation {
455 match => 'm/^(\w+)$/',
456 match_error => 'The $field field may only contain word characters',
464 validate_if => 'password',
465 equals => 'password',
469 enum => [qw(animal vegetable mineral)],
474 The step will continue to display the html form until all of the fields pass
477 See the hash_validation hook and validate hook for more information about how
480 =head1 ADDING JAVASCRIPT DATA VALIDATION TO A STEP
482 You must first provide a hash_validation hook as explained in the previous section.
484 Once you have a hash_validation hook, you would place the following tags
485 into your HTML template.
487 <form name="[% form_name %]" method="post">
492 The "form_name" swap-in places a name on the form that the javascript returned by
493 the js_validation swap-in will be able to find and check for validity.
495 See the hash_validation, js_validation, and form_name hooks for more information.
497 Also, CGI::Ex::validate.js allows for inline errors in addition to or in replacement
498 of an alert message. To use inline errors, you must provide an element in your
499 HTML document where this inline message can be placed. The common way to do it is as
502 <input type="text" name="username"><br>
503 <span class="error" id="username_error">[% username_error %]</span>
505 The span around the error allows for the error css class and it provides a location
506 that the Javascript validation can populate with errors. The [% username_error %] provides
507 a location for errors generated on the server side to be swapped in. If there was no error
508 the [% username_error %] tag would default to "".
510 =head1 ADDING ADDITIONAL TEMPLATE VARIABLES
512 All variables returned by the hash_base, hash_common, hash_form, hash_swap, and
513 hash_errors hooks are available for swapping in templates.
515 The following shows how to add variables using the hash_swap hook on the step "main".
520 choices => [qw(one two three)],
521 "warn" => sub { warn @_ },
525 You could also return the fields from the hash_common hook and they
526 would be available in both the template swapping as well as form
529 See the hash_base, hash_common, hash_form, hash_swap, hash_errors,
530 swap_template, and template_args hooks for more information.
532 The default template engine used is CGI::Ex::Template which is now a subclass
533 of Template::Alloy. The default interface used is TT which is the
534 Template::Toolkit interface. Template::Alloy allows for using TT documents,
535 HTML::Template documents, HTML::Template::Expr documents, Text::Tmpl documents,
536 or Velocity (VTL) documents. See the L<Template::Alloy> documentation
537 for more information.
539 =head1 ADDING ADDITIONAL FORM FILL VARIABLES
541 All variables returned by the hash_base, hash_common, hash_form, and hash_fill hooks
542 are available for filling html fields in on templates.
544 The following shows how to add variables using the hash_fill hook on the step "main".
549 choices => [qw(one two three)],
553 You could also return the fields from the hash_common hook and they would be available
554 in both the form filling as well as in the template swapping.
556 See the hash_base, hash_common, hash_form, hash_swap, hash_errors, fill_template, and
557 fill_args hooks for more information.
559 The default form filler is CGI::Ex::Fill which is similar to HTML::FillInForm but
560 has several benefits. See the CGI::Ex::Fill module for the available options.
562 =head1 FINDING TEMPLATES AND VALIDATION FILES
564 CGI::Ex::App tries to help your applications use a good template directory layout, but allows
565 for you to override everything.
567 External template files are used for storing your html templates and
568 for storing your validation files (if you use externally stored
571 The default file_print hook will look for content on your file system,
572 but it can also be completely overridden to return a reference to a
573 scalar containing the contents of your file (beginning with version 2.14
574 string references can be cached which makes templates passed this way
575 "first class" citizens). Actually it can return
576 anything that Template::Alloy (Template::Toolkit compatible) will
577 treat as input. This templated html is displayed to the user during
578 any step that enters the "print" phase.
580 Similarly the default file_val hook will look for a validation file on
581 the file system, but it too can return a reference to a scalar
582 containing the contents of a validation file. It may actually return
583 anything that the CGI::Ex::Validate get_validation method is able to
584 understand. This validation is used by the default "info_complete"
585 method for verifying if the submitted information passes its specific
586 checks. A more common way of inlining validation is to return a
587 validation hash from a hash_validation hook override.
589 If the default file_print and file_val hooks are used, the following methods
590 are employed for finding templates and validation files on your filesystem (they
591 are also documented more in the HOOKS AND METHODS section.
597 Absolute path or arrayref of paths to the base templates directory. Defaults to
598 base_dir_abs which defaults to ['.'].
602 Relative path inside of the template_path directory where content can be found. Default "".
606 Directory inside of base_dir_rel where files for the current CGI (module) will be
607 stored. Default value is $ENV{SCRIPT_NAME} with path and extension removed.
611 Used with ext_print and ext_val for creating the filename that will be looked for
612 inside of the name_module directory. Default value is the current step.
614 =item ext_print and ext_val
616 Filename extensions added to name_step to create the filename looked for
617 inside of the name_module directory. Default is "html" for ext_print and "val"
622 It may be easier to understand the usage of each of these methods by showing
623 a contrived example. The following is a hypothetical layout for your templates:
625 /home/user/templates/
626 /home/user/templates/chunks/
627 /home/user/templates/wrappers/
628 /home/user/templates/content/
629 /home/user/templates/content/my_app/
630 /home/user/templates/content/my_app/main.html
631 /home/user/templates/content/my_app/step1.html
632 /home/user/templates/content/my_app/step1.val
633 /home/user/templates/content/another_cgi/main.html
635 In this example we would most likely set values as follows:
637 template_path /home/user/templates
641 The name_module method defaults to the name of the running program, but
642 with the path and extension removed. So if we were running
643 /cgi-bin/my_app.pl, /cgi-bin/my_app, or /anypath/my_app, then
644 name_module would default to "my_app" and we wouldn't have to
645 hard code the value. Often it is wise to set the value anyway so
646 that we can change the name of the cgi script without effecting
647 where template content should be stored.
649 Continuing with the example and assuming that name of the step that
650 the user has requested is "step1" then the following values would be
653 template_path /home/user/templates
660 file_print content/my_app/step1.html
661 file_val /home/user/templates/content/my_app/step1.val
663 The call to the template engine would look something like
666 my $t = $self->template_obj({
667 INCLUDE_PATH => $self->template_path, # defaults to base_dir_abs
670 $t->process($self->file_print($step), \%vars);
672 The template engine would then look for the relative file
673 inside of the absolute paths (from template_path).
675 The call to the validation engine would pass the absolute
676 filename that is returned by file_val.
678 The name_module and name_step methods can return filenames with
679 additional directories included. The previous example could
680 also have been setup using the following values:
682 template_path /home/user/templates
684 name_module content/my_app
686 In this case the same values would be returned for the file_print and file_val hooks
687 as were returned in the previous setup.
689 =head1 SYNOPSIS (A LONG "SYNOPSIS")
691 This example script would most likely be in the form of a cgi, accessible via
692 the path http://yourhost.com/cgi-bin/my_app (or however you do CGIs on
693 your system. About the best way to get started is to paste the following
694 code into a cgi script (such as cgi-bin/my_app) and try it out. A detailed
695 walk-through follows in the next section. There is also a longer recipe
696 database example at the end of this document that covers other topics including
697 making your module a mod_perl handler.
699 ### File: /var/www/cgi-bin/my_app (depending upon Apache configuration)
700 ### --------------------------------------------
704 use base qw(CGI::Ex::App);
705 use CGI::Ex::Dump qw(debug);
707 __PACKAGE__->navigate;
709 # my $obj = __PACKAGE__->new;
714 ###------------------------------------------###
718 debug shift->dump_history;
721 sub main_hash_validation {
723 'general no_alert' => 1,
724 'general no_confirm' => 1,
725 'group order' => [qw(username password password2)],
731 match_error => 'You may only use letters and numbers.',
738 equals => 'password',
743 sub main_file_print {
744 # reference to string means ref to content
745 # non-reference means filename
746 return \ "<h1>Main Step</h1>
747 <form method=post name=[% form_name %]>
748 <input type=hidden name=step>
751 <td><b>Username:</b></td>
752 <td><input type=text name=username><span style='color:red' id=username_error>[% username_error %]</span></td>
754 <td><b>Password:</b></td>
755 <td><input type=text name=password><span style='color:red' id=password_error>[% password_error %]</span></td>
757 <td><b>Verify Password:</b></td>
758 <td><input type=text name=password2><span style='color:red' id=password2_error>[% password2_error %]</span></td>
760 <tr><td colspan=2 align=right><input type=submit></td></tr>
770 if ($self->form->{'username'} eq 'bar') {
771 $self->add_errors(username => 'A trivial check to say the username cannot be "bar"');
775 debug $self->form, "Do something useful with form here in the finalize hook.";
778 $self->add_to_swap({success_msg => "We did something"});
779 $self->append_path('success');
780 $self->set_ready_validate(0);
784 sub success_file_print {
785 \ "<div style=background:lightblue>
786 <h1>Success Step - [% success_msg %]</h1>
787 Username: <b>[% username %]</b><br>
788 Password: <b>[% password %]</b><br>
795 Note: This example would be considerably shorter if the html file
796 (file_print) and the validation file (file_val) had been placed in
797 separate files. Though CGI::Ex::App will work "out of the box" as
798 shown it is more probable that any platform using it will customize
799 the various hooks to their own tastes (for example, switching print to
800 use a templating system other than Template::Alloy).
802 =head1 SYNOPSIS STEP BY STEP
804 This section goes step by step over the previous example.
806 Well - we start out with the customary CGI introduction.
811 use base qw(CGI::Ex::App);
812 use CGI::Ex::Dump qw(debug);
814 Note: the "use base" is not normally used in the "main" portion of a script.
815 It does allow us to just do __PACKAGE__->navigate.
817 Now we need to invoke the process:
819 __PACKAGE__->navigate;
821 # my $obj = __PACKAGE__->new;
825 Note: the "exit" isn't necessary - but it is kind of nice to infer
826 that process flow doesn't go beyond the ->navigate call.
828 The navigate routine is now going to try and "run" through a series of
829 steps. Navigate will call the ->path method which should return an
830 arrayref containing the valid steps. By default, if path method has
831 not been overridden, the path method will default first to the step
832 found in form key named ->step_name, then it will fall to the contents
833 of $ENV{'PATH_INFO'}. If navigation runs out of steps to run it will
834 run the step found in ->default_step which defaults to 'main'. So the
835 URI '/cgi-bin/my_app' would run the step 'main' first by default. The
836 URI '/cgi-bin/my_app?step=foo' would run the step 'foo' first. The
837 URI '/cgi-bin/my_app/bar' would run the step 'bar' first.
839 CGI::Ex::App allows for running steps in a preset path or each step may
840 choose the next step that should follow. The navigate
841 method will go through one step of the path at a time and see if it is
842 completed (various methods determine the definition of "completed").
843 This preset type of path can also be automated using the CGI::Path
844 module. Rather than using a preset path, CGI::Ex::App also has
845 methods that allow for dynamic changing of the path, so that each step
846 can determine which step to do next (see the jump, append_path,
847 insert_path, and replace_path methods).
849 During development it would be nice to see what happened during the
850 course of our navigation. This is stored in the arrayref contained in
851 ->history. There is a method that is called after all of the navigation
852 has taken place called "post_navigate". This chunk will display history after we
853 have printed the content.
856 debug shift->dump_history;
857 } # show what happened
859 Ok. Finally we are looking at the methods used by each step of the path. The
860 hook mechanism of CGI::Ex::App will look first for a method ${step}_${hook_name}
861 called before falling back to the method named $hook_name. Internally in the
862 code there is a call that looks like $self->run_hook('hash_validation', $step). In
863 this case the step is main. The dispatch mechanism finds our method at the following
866 sub main_hash_validation { ... }
868 The process flow will see if the data is ready to validate. Once it is ready
869 (usually when the user presses the submit button) the data will be validated. The
870 hash_validation hook is intended to describe the data and will be tested
871 using CGI::Ex::Validate. See the CGI::Ex::Validate perldoc for more
872 information about the many types of validation available.
874 sub main_file_print { ... }
876 The navigation process will see if user submitted information (the form)
877 is ready for validation. If not, or if validation fails, the step needs to
878 be printed. Eventually the file_print hook is called. This hook should
879 return either the filename of the template to be printed, or a reference
880 to the actual template content. In this example we return a reference
881 to the content to be printed (this is useful for prototyping applications
882 and is also fine in real world use - but generally production applications
883 use external html templates).
885 A few things to note about the template:
887 First, we add a hidden form field called step. This will be filled in
888 automatically at a later point with the current step we are on.
890 We provide locations to swap in inline errors.
892 <span style="color:red" id="username_error">[% username_error %]</span>
894 As part of the error html we name each span with the name of the error. This
895 will allow for us to have Javascript update the error spots when the javascript
898 At the very end we add the TT variable [% js_validation %]. This swap in is
899 provided by the default hash_base hook and will provide for form data to be
900 validated using javascript.
902 Once the process flow has deemed that the data is validated, it then calls
903 the finalize hook. Finalize is where the bulk of operations should go.
904 We'll look at it more in depth.
908 my $form = $self->form;
910 At this point, all of the validated data is in the $form hashref.
912 if ($form->{'username'} eq 'bar') {
913 $self->add_errors(username => 'A trivial check to say the username cannot be "bar"');
917 It is most likely that though the data is of the correct type and formatting,
918 it still isn't completely correct. This previous section shows a hard coded
919 test to see if the username was 'bar'. If it was then an appropriate error will
920 be set, the routine returns 0 and the run_step process knows that it needs to
921 redisplay the form page for this step. The username_error will be shown inline.
922 The program could do more complex things such as checking to see if the username
923 was already taken in a database.
925 debug $form, "Do something useful with form here in the finalize hook.";
927 This debug $form piece is simply a place holder. It is here that the program would
928 do something useful such as add the information to a database.
931 $self->add_to_swap({success_msg => "We did something"});
933 Now that we have finished finalize, we add a message that will be passed to the template
936 $self->append_path('success');
937 $self->set_ready_validate(0);
939 The program now needs to move on to the next step. In this case we want to
940 follow with a page that informs us we succeeded. So, we append a step named "success".
941 We also call set_ready_validate(0) to inform the navigation control that the
942 form is no longer ready to validate - which will cause the success page to
943 print without trying to validate the data. It is normally a good idea
944 to set this as leaving the engine in a "ready to validate" state can result
945 in an recursive loop (that will be caught).
950 We then return 1 which tells the engine that we completed this step successfully
951 and it needs to move on to the next step.
953 Finally we run the "success" step because we told it to. That step isn't
954 ready to validate so it prints out the template page.
956 For more of a real world example, it would be good to read the sample recipe db
957 application included at the end of this document.
959 =head1 AVAILABLE METHODS / HOOKS
961 CGI::Ex::App's dispatch system works on the principles of hooks (which
962 are essentially glorified method lookups). When the run_hook method
963 is called, CGI::Ex::App will look for a corresponding method call for
964 that hook for the current step name. It is perhaps easier to show than
967 If we are calling the "print" hook for the step "edit" we would call
970 $self->run_hook('print', 'edit', $template, \%swap, \%fill);
972 This would first look for a method named "edit_print". If it is unable to
973 find a method by that name, it will look for a method named "print". If it
974 is unable to find this method - it will die.
976 If allow_morph is set to true, the same methods are searched for but it becomes
977 possible to move some of those methods into an external package.
979 See the discussions under the methods named "find_hook" and "run_hook" for more details.
981 The following is the alphabetical list of methods and hooks.
985 =item allow_morph (hook)
987 Should return true if this step is allowed to "morph" the current App
988 object into another package. Default is false. It is passed a single
989 argument of the current step. For more granularity, if true value is
990 a hash, the step being morphed to must be in the hash.
992 To enable morphing for all steps, add the following:
994 sub allow_morph { 1 }
996 To enable morph on specific steps, do either of the following:
1008 my ($self, $step) = @_;
1009 return $step =~ /^(edit|delete)$/;
1012 See the morph "hook" for more information.
1014 =item allow_nested_morph (method)
1016 Similar to the allow_morph hook, but allows for one more level of morphing.
1017 This is useful in cases where the base class was morphed early on, or
1018 if a step needs to call a sub-step but morph first.
1020 See the allow_morph and the morph method for more information.
1022 Should return a boolean value or hash of allowed steps - just as the
1023 allow_morph method does.
1025 =item append_path (method)
1027 Arguments are the steps to append. Can be called any time. Adds more
1028 steps to the end of the current path.
1030 =item auth_args (method)
1032 Should return a hashref that will be passed to the auth_obj method
1033 which should return a CGI::Ex::Auth compatible object.
1034 It is augmented with arguments that integrate it into CGI::Ex::App.
1036 See the get_valid_auth method and the CGI::Ex::Auth documentation.
1040 login_header => '<h1>My login header</h1>',
1041 login_footer => '[% TRY %][% INCLUDE login/login_footer.htm %][% CATCH %]<!-- [% error %] -->[% END %]',
1042 secure_hash_keys => [qw(aaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbb ccccccccccccccccccccccc 2222222222222)],
1043 # use_blowfish => 'my_blowfish_key',
1047 =item auth_data (method)
1049 Contains authentication data stored during the get_valid_auth method.
1050 The data is normally blessed into the CGI::Ex::Auth::Data package which
1051 evaluates to false if there was an error and true if the authentication
1052 was successful - so this data can be defined but false.
1054 See the get_valid_auth method.
1056 =item auth_obj (method)
1058 Passed auth_args. Should return a CGI::Ex::Auth compatible object. Default
1059 is to call CGI::Ex::Auth->new with the passed args.
1061 =item base_dir_abs (method)
1063 Used as the absolute base directory to find template, validation and conf files.
1064 It may return a single value or an arrayref of values, or a coderef that
1065 returns an arrayref or coderef of values. You may pass base_dir_abs
1066 as a parameter in the arguments passed to the "new" method.
1068 Default value is ['.'].
1070 For example, to pass multiple paths, you would use something
1071 similar to the following:
1074 return ['/my/path/one', '/some/other/path'];
1077 The base_dir_abs value is used by template_path along with the
1078 base_dir_rel, name_module, name_step, ext_print and ext_values for
1079 determining the values returned by the default file_print and file_val
1080 hooks. See those methods for further discussion.
1082 See the section on FINDING TEMPLATES for further discussion.
1084 The base_dir_abs method is also used as the default value for conf_path and vob_path.
1086 =item base_dir_rel (method)
1088 Added as a relative base directory to content under the base_dir_abs directory.
1090 Default value is "".
1092 The template_path method is used as top level where template includes may
1093 pull from, while the base_dir_rel is directory relative to the template_path
1094 where the content files will be stored.
1096 A value for base_dir_rel may passed as a parameter in the arguments passed
1099 See the template_path and base_dir_abs methods for more discussion.
1101 See the section on FINDING TEMPLATES for further discussion.
1103 =item cleanup_user (method)
1105 Used as a hook during get_valid_auth. Allows for cleaning
1106 up the username. See the get_valid_auth method.
1109 my ($self, $user) = @_;
1113 =item clear_app (method)
1115 If the same CGI::Ex::App based object is used to run multiple
1116 navigate sessions, the clear_app method should be called which
1117 will attempt to clear as much session information as it can.
1118 The following items will be cleared:
1128 _morph_lineage_start_index
1137 Used by default in init_from_conf if load_conf returns true.
1138 Will try to read the file returned by the conf_file method
1139 using the object returned by conf_obj using that object's read
1140 method. If conf_validation returns a non-empty hashref, the
1141 conf hash will be validated using $self->vob->validate (see the
1144 This method may be used for other purposes as well (including when
1145 load_conf is false)..
1147 Caches results in $self->{'conf'}.
1149 If the conf_file can't be found, the method will die unless
1150 conf_die_on_fail returns 0 (defaults to true).
1156 Defaults to $self->{'conf_args'} which defaults to {}. Will have
1157 paths => $self->conf_path added before passing to CGI::Ex::Conf->new.
1159 =item conf_file (method)
1161 Used by conf for finding the configuration file to load. Defaults
1162 to $self->{'conf_file'} which defaults $self->name_module with the extention
1163 returned by $self->ext_conf added on. For example, if name_module
1164 returns "my_app" and ext_conf returns "ini" the value returned will
1167 The value returned can absolute. If the value will be searched for
1168 in the paths passed to conf_obj.
1170 The ext_conf may be any of those extentions understood by CGI::Ex::Conf.
1174 Used by the conf method to load the file returned by conf_file. Defaults
1175 to conf_obj which defaults to loading args from conf_args, adding in paths
1176 returned by conf_path, and calling CGI::Ex::Conf->new.
1178 Any object that provides a read method that returns a hashref can be used.
1182 Defaults to $self->{'conf_path'} which defaults to base_dir_abs. Should be
1183 a path or an arrayref of paths to look the configuration file returned by
1184 conf_file when that file is not absolute.
1186 =item conf_validation
1188 Used by default conf method.
1189 Defaults to an empty hashref. If non-empty hashref is passed, the
1190 hashref returned by conf_obj->read will be validated using the hashref
1191 returned by conf_validation.
1193 =item current_step (method)
1195 Returns the current step that the nav_loop is functioning on.
1197 =item default_step (method)
1199 Step to show if the path runs out of steps. Default value is the
1200 'default_step' property which defaults to 'main'.
1202 If nav_loop runs of the end of the path (runs out of steps), this
1203 method is called, the step is added to the path, and nav_loop calls
1206 =item destroy (method)
1208 Called at the end of navigate after all other actions have run. Can
1209 be used for undoing things done in the ->init method called during
1212 =item dump_history (method)
1214 Show simplified trace information of which steps were called, the
1215 order they were called in, the time they took to run, and a brief list
1216 of the output (to see the full response returned by each hook, pass a
1217 true value as the only argument to dump_history -
1218 $self->dump_history(1)). Indentation is also applied to show which
1219 hooks called other hooks.
1222 The first line shows the amount of time elapsed for the entire
1223 navigate execution. Subsequent lines contain:
1225 Step - the name of the current step.
1226 Hook - the name of the hook being called.
1227 Found - the name of the method that was found.
1228 Time - the total elapsed seconds that method took to run.
1229 Output - the response of the hook - shown in shortened form.
1231 Note - to get full output responses - pass a true value to
1232 dump_history - or just call ->history. Times displayed are to 5
1233 decimal places - this accuracy can only be provided if the Time::HiRes
1234 module is installed on your system (it will only be used if installed).
1236 It is usually best to print this history during the post_navigate
1237 method as in the following:
1239 use CGI::Ex::Dump qw(debug);
1240 sub post_navigate { debug shift->dump_history }
1242 The following is a sample output of dump_history called from the
1243 sample recipe application at the end of this document. The step
1246 debug: admin/Recipe.pm line 14
1247 shift->dump_history = [
1249 "view - require_auth - require_auth - 0.00001 - 0",
1250 "view - run_step - run_step - 0.00488 - 1",
1251 " view - pre_step - pre_step - 0.00003 - 0",
1252 " view - skip - view_skip - 0.00004 - 0",
1253 " view - prepare - prepare - 0.00003 - 1",
1254 " view - info_complete - info_complete - 0.00010 - 0",
1255 " view - ready_validate - ready_validate - 0.00004 - 0",
1256 " view - prepared_print - prepared_print - 0.00441 - 1",
1257 " view - hash_base - hash_base - 0.00009 - HASH(0x84ea6ac)",
1258 " view - hash_common - view_hash_common - 0.00148 - HASH(0x8310a20)",
1259 " view - hash_form - hash_form - 0.00004 - HASH(0x84eaa78)",
1260 " view - hash_fill - hash_fill - 0.00003 - {}",
1261 " view - hash_swap - hash_swap - 0.00003 - {}",
1262 " view - hash_errors - hash_errors - 0.00003 - {}",
1263 " view - print - print - 0.00236 - 1",
1264 " view - file_print - file_print - 0.00024 - recipe/view.html",
1265 " view - name_module - name_module - 0.00007 - recipe",
1266 " view - name_step - name_step - 0.00004 - view",
1267 " view - swap_template - swap_template - 0.00161 - <html> ...",
1268 " view - template_args - template_args - 0.00008 - HASH(0x865abf8)",
1269 " view - fill_template - fill_template - 0.00018 - 1",
1270 " view - fill_args - fill_args - 0.00003 - {}",
1271 " view - print_out - print_out - 0.00015 - 1",
1272 " view - post_print - post_print - 0.00003 - 0"
1275 =item error_step (method)
1277 Defaults to "__error". The name of a step to run should a dying error
1278 be caught by the default handle_error method. See the handle_error method.
1280 =item exit_nav_loop (method)
1282 This method should not normally used but there is no problem with
1283 using it on a regular basis. Essentially it is a "goto" that allows
1284 for a long jump to the end of all nav_loops (even if they are
1285 recursively nested). This effectively short circuits all remaining
1286 hooks for the current and remaining steps. It is used to allow the
1287 ->jump functionality. If the application has morphed, it will be
1288 unmorphed before returning. Also - the post_navigate method will
1293 Used by the default conf_file method. Defaults to $self->{'ext_conf'} which
1294 defaults to 'pl' meaning that the read configuration file should return a
1297 =item ext_print (method)
1299 Added as suffix to "name_step" during the default file_print hook.
1301 Default value is 'html'.
1303 For example, if name_step returns "foo" and ext_print returns "html"
1304 then the file "foo.html" will be searched for.
1306 See the section on FINDING TEMPLATES for further discussion.
1308 =item ext_val (method)
1310 Added as suffix to "name_step" during the default file_val hook.
1312 Default value is 'val'.
1314 For example, if name_step returns "foo" and ext_val returns "val"
1315 then the file "foo.val" will be searched for.
1317 See the section on FINDING TEMPLATES for further discussion.
1319 =item fill_args (hook)
1321 Returns a hashref of args that will be passed to the CGI::Ex::Fill::fill.
1322 It is augmented with the template to swap and the fill hash. This
1323 could be useful if you needed to only swap a particular form on the template
1324 page. Arguments are passed directly to the fill function.
1326 sub fill_args { {target => 'my_form'} }
1328 =item fill_template (hook)
1330 Arguments are a template and a hashref. Takes the template that was
1331 prepared using swap_template, and swaps html form fields using the
1332 passed hashref. Overriding this method can control the fill behavior.
1334 Calls the fill_args hook prior to calling CGI::Ex::Fill::fill
1336 =item file_print (hook)
1338 Returns a filename of the content to be used in the default print
1339 hook. Adds method base_dir_rel to hook name_module, and name_step and
1340 adds on the default file extension found in $self->ext_print which
1341 defaults to the property $self->{ext_print} which will default to
1342 ".html". Should return a filename relative to template_path that can be
1343 swapped using Template::Alloy, or should be a scalar reference to
1344 the template content that can be swapped. This will be used by the
1347 sub template_path { '/var/www/templates' }
1348 sub base_dir_rel { 'content' }
1349 sub name_module { 'recipe' }
1350 sub ext_print { 'html' } # default
1352 # ->file_print('this_step')
1353 # would return 'content/recipe/this_step.html'
1354 # the template engine would look in '/var/www/templates'
1355 # for a file by that name
1357 It may also return a reference to a string containing the html template.
1358 This is useful for prototyping applications and/or keeping all of
1359 the data for the application in a single location.
1361 =item file_val (hook)
1363 Returns a filename containing the validation. Performs the same as
1364 file_print, but uses ext_val to get the extension, and it adds
1365 vob_path (which defaults to template_path which defaults to
1366 base_dir_abs) onto the returned value (file_print is relative to
1367 template_path, while file_val is fully qualified with vob_path). If
1368 vob_path returns an arrayref of paths, then each path is checked for
1369 the existence of the file.
1371 The file should be readable by CGI::Ex::Validate::get_validation.
1373 This hook is only necessary if the hash_validation hook has not been
1376 This method an also return a hashref containing the validation - but
1377 then you may have wanted to override the hash_validation hook.
1379 =item finalize (hook)
1381 Defaults to true. Used to do whatever needs to be done with the data once
1382 prepare has returned true and info_complete has returned true. On failure
1383 the print operations are ran. On success navigation moves on to the next
1386 This is normally were there core logic of a script will occur (such as
1387 adding to a database, or updating a record). At this point, the data
1388 should be validated. It is possible to do additional validation
1389 and return errors using code such as the following.
1391 if (! $user_is_unique) {
1392 $self->add_errors(username => 'The username was already used');
1396 =item find_hook (method)
1398 Called by run_hook. Arguments are a hook name, a step name. It
1399 should return an arrayref containing the code_ref to run, and the
1400 name of the method looked for. It uses ->can to find the appropriate
1403 my $code = $self->hook('finalize', 'main');
1404 ### will look first for $self->main_finalize;
1405 ### will then look for $self->finalize;
1407 This system is used to allow for multiple steps to be in the same
1408 file and still allow for moving some steps out to external sub classed
1409 packages (if desired).
1411 If the application has successfully morphed via the morph method and
1412 allow_morph then it is not necessary to add the step name to the
1413 beginning of the method name as the morphed packages method will
1414 override the base package (it is still OK to use the full method name
1415 "${step}_hookname").
1417 See the run_hook method and the morph method for more details.
1419 =item first_step (method)
1421 Returns the first step of the path. Note that first_step may not be the same
1422 thing as default_step if the path was overridden.
1424 =item forbidden_step (method)
1426 Defaults to "__forbidden". The name of a step to run should the current
1427 step name be invalid, or if a step found by the default path method
1428 is invalid. See the path method.
1432 Returns a hashref of the items passed to the CGI. Returns
1433 $self->{form} which defaults to CGI::Ex::get_form.
1435 =item form_name (hook)
1437 Return the name of the form to attach the js validation to. Used by
1440 =item get_pass_by_user (method)
1442 This method is passed a username and the authentication object. It
1443 should return the password for the given user. See the get_pass_by_user
1444 method of CGI::Ex::Auth for more information. Installed as a hook
1445 to the authentication object during the get_valid_auth method.
1447 =item get_valid_auth (method)
1449 If require_auth hook returns true on any given step then get_valid_auth will be called.
1451 It will call auth_args to get some default args to pass to
1452 CGI::Ex::Auth->new. It augments the args with sensible defaults that
1453 App already provides (such as form, cookies, and template facilities).
1454 It also installs hooks for the get_pass_by_user, cleanup_user, and verify_user
1455 hooks of CGI::Ex::Auth.
1457 It stores the $auth->last_auth_data in $self->auth_data for later use. For
1458 example, to get the authenticated user:
1460 sub require_auth { 1 }
1463 my ($self, $user) = @_;
1467 sub get_pass_by_user {
1468 my ($self, $user) = @_;
1469 my $pass = $self->some_method_to_get_the_pass($user);
1475 login_header => '<h1>My login header</h1>',
1476 login_footer => '[% TRY %][% INCLUDE login/login_footer.htm %][% CATCH %]<!-- [% error %] -->[% END %]',
1480 sub main_hash_swap {
1482 my $user = $self->auth_data->{'user'};
1483 return {user => $user};
1486 Successful authentication is cached for the duration of the
1487 nav_loop so multiple steps will run the full authentication routine
1490 Full customization of the login process and the login template can
1491 be done via the auth_args hash. See the auth_args method and
1492 CGI::Ex::Auth perldoc for more information.
1494 =item handle_error (method)
1496 If anything dies during execution, handle_error will be called with
1497 the error that had happened. Default action is to try running the
1498 step returned by the error_step method.
1500 =item hash_base (hook)
1502 A hash of base items to be merged with hash_form - such as pulldown
1503 menus, javascript validation, etc. It will now also be merged with
1504 hash_fill, so it can contain default fillins as well. It can be
1505 populated by passing a hash to ->add_to_base. By default a sub
1506 similar to the following is what is used for hash_common. Note the
1507 use of values that are code refs - so that the js_validation and
1508 form_name hooks are only called if requested:
1511 my ($self, $step) = @_;
1512 return $self->{hash_base} ||= {
1513 script_name => $ENV{SCRIPT_NAME},
1514 js_validation => sub { $self->run_hook('js_validation', $step) },
1515 form_name => sub { $self->run_hook('form_name', $step) },
1519 =item hash_common (hook)
1521 Almost identical in function and purpose to hash_base. It is
1522 intended that hash_base be used for common items used in various
1523 scripts inheriting from a common CGI::Ex::App type parent. Hash_common
1524 is more intended for step level populating of both swap and fill.
1526 =item hash_errors (hook)
1528 Called in preparation for print after failed prepare, info_complete,
1529 or finalize. Should contain a hash of any errors that occurred. Will
1530 be merged into hash_form before the pass to print. Each error that
1531 occurred will be passed to method format_error before being added to
1532 the hash. If an error has occurred, the default validate will
1533 automatically add {has_errors =>1}. To the error hash at the time of
1534 validation. has_errors will also be added during the merge in case the
1535 default validate was not used. Can be populated by passing a hash to
1536 ->add_to_errors or ->add_errors.
1538 =item hash_fill (hook)
1540 Called in preparation for print after failed prepare, info_complete,
1541 or finalize. Should contain a hash of any items needed to be filled
1542 into the html form during print. Items from hash_form, hash_base, and
1543 hash_common will be layered together. Can be populated by passing a
1544 hash to ->add_to_fill.
1546 By default - forms are sticky and data from previous requests will try
1547 and populate the form. You can use the fill_template hook to disable
1548 templating on a single page or on all pages.
1550 This method can be used to pre-populate the form as well (such as on an
1551 edit step). If a form fails validation, hash_fill will also be called
1552 and will only want the submitted form fields to be sticky. You can
1553 use the ready_validate hook to prevent pre-population in these cases as
1556 sub edit_hash_fill {
1559 return {} if $self->run_hook('ready_validate', $step);
1563 ### get previous values from the database
1568 =item hash_form (hook)
1570 Called in preparation for print after failed prepare, info_complete,
1571 or finalize. Defaults to ->form. Can be populated by passing a hash
1574 =item hash_swap (hook)
1576 Called in preparation for print after failed prepare, info_complete,
1577 or finalize. Should contain a hash of any items needed to be swapped
1578 into the html during print. Will be merged with hash_base,
1579 hash_common, hash_form, and hash_errors. Can be populated by passing
1580 a hash to ->add_to_swap.
1582 The hash will be passed as the second argument to swap_template.
1584 =item hash_validation (hook)
1586 Returns a hash of the validation information to check form against.
1587 By default, will look for a filename using the hook file_val and will
1588 pass it to CGI::Ex::Validate::get_validation. If no file_val is
1589 returned or if the get_validation fails, an empty hash will be returned.
1590 Validation is implemented by ->vob which loads a CGI::Ex::Validate object.
1592 =item history (method)
1594 Returns an arrayref which contains trace history of which hooks of
1595 which steps were ran. Useful for seeing what happened. In general -
1596 each line of the history will show the current step, the hook
1597 requested, and which hook was actually called.
1599 The dump_history method shows a short condensed version of this
1600 history which makes it easier to see what path was followed.
1602 In general, the arrayref is free for anything to push onto which will
1603 help in tracking other occurrences in the program as well.
1605 =item info_complete (hook)
1607 Calls the ready_validate hook to see if data is ready to validate. If
1608 so it calls the validate hook to validate the data. Should make
1609 sure the data is ready and valid. Will not be run unless
1610 prepare returns true (default).
1614 Called by the default new method. Allows for any object
1615 initilizations that may need to take place. Default action does
1618 =item init_from_conf (method)
1620 Called by the default new method. If load_conf is true, then the
1621 conf method will be called and the keys returned will be added to
1624 This method is called after the init method. If you need to further
1625 fix up values added during init_from_conf, you can use the pre_navigate
1628 =item insert_path (method)
1630 Arguments are the steps to insert. Can be called any time. Inserts
1631 the new steps at the current path location.
1633 =item is_authed (method)
1635 Returns true if the object has successful authentication data. It
1636 returns false if the object has not been authenticated.
1638 =item js_uri_path (method)
1640 Return the URI path where the CGI/Ex/yaml_load.js and
1641 CGI/Ex/validate.js files can be found. This will default to
1642 "$ENV{SCRIPT_NAME}/js" if the path method has not been overridden,
1643 otherwise it will default to "$ENV{SCRIPT_NAME}?step=js&js=" (the
1644 latter is more friendly with overridden paths). A default handler for
1645 the "js" step has been provided in "js_run_step" (this handler will
1646 nicely print out the javascript found in the js files which are
1647 included with this distribution. js_run_step will work properly with the
1648 default "path" handler.
1650 =item js_validation (hook)
1652 Requires JSON or YAML. Will return Javascript that is capable of
1653 validating the form. This is done using the capabilities of
1654 CGI::Ex::Validate. This will call the hook hash_validation which will
1655 then be encoded either json or into yaml and placed in a javascript
1656 string. It will also call the hook form_name to determine which html
1657 form to attach the validation to. The method js_uri_path is called to
1658 determine the path to the appropriate validate.js files. If the
1659 method ext_val is htm, then js_validation will return an empty string
1660 as it assumes the htm file will take care of the validation itself.
1661 In order to make use of js_validation, it must be added to the
1662 variables returned by either the hash_base, hash_common, hash_swap or
1663 hash_form hook (see examples of hash_base used in this doc).
1665 By default it will try and use JSON first and then fail to YAML and
1666 then will fail to returning an html comment that does nothing.
1670 This method should not normally be used but is fine to use it on a
1671 regular basis. It provides for moving to the next step at any point
1672 during the nav_loop. It effectively short circuits the remaining
1673 hooks for the current step. It does increment the recursion counter
1674 (which has a limit of ->recurse_limit - default 15). It is normally
1675 better to allow the other hooks in the loop to carry on their normal
1676 functions and avoid jumping. (Essentially, this hook behaves like a
1677 goto method to bypass everything else and continue at a different
1678 location in the path - there are times when it is necessary or useful
1681 Jump takes a single argument which is the location in the path to jump
1682 to. This argument may be either a step name, the special strings
1683 "FIRST, LAST, CURRENT, PREVIOUS, OR NEXT" or the number of steps to
1684 jump forward (or backward) in the path. The default value, 1,
1685 indicates that CGI::Ex::App should jump to the next step (the default
1686 action for jump). A value of 0 would repeat the current step (watch
1687 out for recursion). A value of -1 would jump to the previous step.
1688 The special value of "LAST" will jump to the last step. The special
1689 value of "FIRST" will jump back to the first step. In each of these
1690 cases, the path array returned by ->path is modified to allow for the
1691 jumping (the path is modified so that the path history is not destroyed
1692 - if we were on step 3 and jumped to one, that path would contain
1693 1, 2, 3, *1, 2, 3, 4, etc and we would be at the *).
1695 ### goto previous step
1696 $self->jump($self->previous_step);
1697 $self->jump('PREVIOUS');
1701 $self->jump($self->next_step);
1702 $self->jump('NEXT');
1706 ### goto current step (repeat)
1707 $self->jump($self->current_step);
1708 $self->jump('CURRENT');
1712 $self->jump($self->last_step);
1713 $self->jump('LAST');
1716 $self->jump($self->first_step);
1717 $self->jump('FIRST');
1719 =item last_step (method)
1721 Returns the last step of the path. Can be used to jump to the last step.
1723 =item load_conf (method)
1725 Defaults to ->{load_conf} which defaults to false. If true, will
1726 allow keys returned by the conf method to be added to $self during
1727 the init_from_conf method.
1729 Enabling this method allows for out-of-the-box file based configuration.
1731 =item morph (method)
1733 Allows for temporarily "becoming" another object type for the
1734 execution of the current step. This allows for separating some steps
1735 out into their own packages.
1737 Morph will only run if the method allow_morph returns true.
1738 Additionally if the allow_morph returns a hash ref, morph will only
1739 run if the step being morphed to is in the hash. Morph also passes
1740 the step name to allow_morph.
1742 The morph call occurs at the beginning of the step loop. A
1743 corresponding unmorph call occurs before the loop is exited. An
1744 object can morph several levels deep if allow_nested_morph returns
1745 true. For example, an object running as Foo::Bar that is looping on
1746 the step "my_step" that has allow_morph = 1, will do the following:
1748 Call the morph_package hook (which would default to returning
1749 Foo::Bar::MyStep in this case)
1751 Translate this to a package filename (Foo/Bar/MyStep.pm) and try
1752 and require it, if the file can be required, the object is blessed
1755 Call the fixup_after_morph method.
1757 Continue on with the run_step for the current step.
1759 At any exit point of the loop, the unmorph call is made which
1760 re-blesses the object into the original package.
1762 Samples of allowing morph:
1764 sub allow_morph { 1 }
1766 sub allow_morph { {edit => 1} }
1768 sub allow_morph { my ($self, $step) = @_; return $step eq 'edit' }
1770 It is possible to call morph earlier on in the program. An example of
1771 a useful early use of morph would be as in the following code:
1773 sub allow_morph { 1 }
1777 if ($ENV{'PATH_INFO'} && $ENV{'PATH_INFO'} =~ s|^/(\w+)||) {
1779 $self->morph($step);
1780 $ENV{'PATH_INFO'} = "/$step";
1781 $self->stash->{'base_morphed'} = 1;
1788 $self->unmorph if $self->stash->{'base_morphed'};
1791 If this code was in a module Base.pm and the cgi running was cgi/base
1796 and you created a sub module that inherited Base.pm called
1797 Base/Ball.pm -- you could then access it using cgi/base/ball. You
1798 would be able to pass it steps using either cgi/base/ball/step_name or
1799 cgi/base/ball?step=step_name - Or Base/Ball.pm could implement its
1800 own path. It should be noted that if you do an early morph, it is
1801 suggested to provide a call to unmorph. And if you want to let your
1802 early morphed object morph again - you will need to provide
1804 sub allow_nested_morph { 1 }
1806 With allow_nested_morph enabled you could create the file
1807 Base/Ball/StepName.pm which inherits Base/Ball.pm. The Base.pm, with
1808 the custom init and default path method, would automatically morph us
1809 first into a Base::Ball object (during init) and then into a
1810 Base::Ball::StepName object (during the navigation loop).
1812 Since it is complicated to explain - it may be a bit complicated to
1813 those who will try to follow your code later. CGI::Ex::App provides
1814 many ways to do things, but use the best one for your situation.
1816 =item morph_package (hook)
1818 Used by morph. Return the package name to morph into during a morph
1819 call. Defaults to using the current object type as a base. For
1820 example, if the current object running is a Foo::Bar object and the
1821 step running is my_step, then morph_package will return
1824 Because of the way that run_hook works, it is possible that several
1825 steps could be located in the same external file and overriding morph_package
1826 could allow for this to happen.
1828 See the morph method.
1830 =item name_module (hook)
1832 Return the name (relative path) that should be pre-pended to name_step
1833 during the default file_print and file_val lookups. Defaults to
1834 the value in $self->{name_module} which in turn defaults to the name
1835 of the current script.
1837 cgi-bin/my_app.pl => my_app
1838 cgi/my_app => my_app
1840 This method is provided so that each cgi or mod_perl application can
1841 have its own directory for storing html for its steps.
1843 See the file_print method for more information.
1845 See the section on FINDING TEMPLATES for further discussion.
1847 =item name_step (hook)
1849 Return the step (appended to name_module) that should used when
1850 looking up the file in file_print and file_val lookups. Defaults to
1853 See the section on FINDING TEMPLATES for further discussion.
1855 =item nav_loop (method)
1857 This is the main loop runner. It figures out the current path
1858 and runs all of the appropriate hooks for each step of the path. If
1859 nav_loop runs out of steps to run (which happens if no path is set, or if
1860 all other steps run successfully), it will insert the ->default_step into
1861 the path and run nav_loop again (recursively). This way a step is always
1862 assured to run. There is a method ->recurse_limit (default 15) that
1863 will catch logic errors (such as inadvertently running the same
1864 step over and over and over because there is either no hash_validation,
1865 or the data is valid but the set_ready_validate(0) method was not called).
1867 =item navigate (method)
1869 Takes a class name or a CGI::Ex::App object as arguments. If a class
1870 name is given it will call the "new" method to instantiate an object
1871 by that class (passing any extra arguments to the new method). All
1872 returns from navigate will return the object.
1874 The method navigate is essentially a safe wrapper around the ->nav_loop
1875 method. It will catch any dies and pass them to ->handle_error.
1877 This starts the process flow for the path and its steps.
1879 =item navigate_authenticated (method)
1881 Same as the method navigate but calls ->require_auth(1) before
1882 running. It will only work if the navigate_authenticated method
1883 has not been overwritten. See the require_auth method.
1885 =item new (class method)
1887 Object creator. Takes a hashref of arguments that will become the
1888 initial properties of the object. Calls the init method once the
1889 object has been blessed to allow for any other initilizations.
1891 my $app = MyApp->new({name_module => 'my_app'});
1893 =item next_step (hook and method)
1895 Returns the next step in the path. If there is no next step, it
1896 returns the default_step.
1898 It can be used as a method to return the next step in the path
1899 to pass to a method such as ->jump.
1901 It is also used as a hook by the refine_path hook. If there is no
1902 more steps, it will call the next_step hook to try and find a step to
1907 Return an arrayref (modifiable) of the steps in the path. For each
1908 step the run_step hook and all of its remaining hooks will be run.
1910 Hook methods are looked up and ran using the method "run_hook" which
1911 uses the method "find_hook" to lookup the hook. A history of ran
1912 hooks is stored in the array ref returned by $self->history.
1914 If path has not been defined, the method will look first in the form
1915 for a key by the name found in ->step_key. It will then look in
1916 $ENV{'PATH_INFO'}. It will use this step to create a path with that
1917 one step as its contents. If a step is passed in via either of these
1918 ways, the method will call valid_steps to make sure that the step
1919 is valid (by default valid_steps returns undef - which means that
1920 any step is valid). Any step beginning with _ can not be passed in
1921 and are intended for use on private paths. If a non-valid step is
1922 found, then path will be set to contain a single step of ->forbidden_step.
1924 For the best functionality, the arrayref returned should be the same
1925 reference returned for every call to path - this ensures that other
1926 methods can add to the path (and will most likely break if the
1927 arrayref is not the same).
1929 If navigation runs out of steps to run, the default step found in
1930 default_step will be run. This is what allows for us to default
1931 to the "main" step for many applications.
1933 =item path_info_map (hook)
1935 Used to map path_info parts to form variables. Similar to the
1936 path_info_map_base method. See the path_info_map_base method
1937 for a discussion of how to use this hook.
1939 =item path_info_map_base (method)
1941 Called during the default path method. It is used to custom map portions
1942 of $ENV{'PATH_INFO'} to form values. If should return an arrayref of
1943 arrayrefs where each child arrayref contains a regex qr with match parens
1944 as the first element of the array. Subsequent elements of the array are
1945 the key names to store the corresponding matched value from the regex under.
1946 The outer arrayref is iterated until it one of child arrayrefs matches
1947 against $ENV{'PATH_INFO'}. The matched values are only added to the form if
1948 there is not already a defined value for that key in the form.
1950 The default value returned by this method looks something like the following:
1952 sub path_info_map_base {
1953 return [[qr{^/(\w+)}, $self->step_key]];
1956 This example would map the following PATH_INFO string as follows:
1960 # $self->form->{'step'} now equals "my_step"
1962 The following is another example:
1964 sub path_info_map_base {
1966 [qr{^/([^/]+)/(\w+)}, 'username', $self->step_key],
1967 [qr{^/(\w+)}, $self->step_key],
1971 # the PATH_INFO /my_step
1973 # $self->form->{'step'} now equals "my_step"
1975 # but with the PATH_INFO /my_user/my_step
1976 # $self->form->{'step'} now equals "my_step"
1977 # and $self->form->{'username'} equals "my_user"
1979 In most cases there is not a need to override the path_info_map_base
1980 method, but rather override the path_info_map hook for a particular step.
1981 When the step is being run, just before the run_step hook is called, the
1982 path_info_map hook is called. The path_info_map hook is similar to
1983 the path_info_map_base method, but is used to allow step level manipulation
1984 of form based on elements in the $ENV{'PATH_INFO'}.
1986 sub my_step_path_info_map {
1987 return [[qr{^/my_step/(\w+)$}, 'username']];
1990 # the PATH_INFO /my_step/my_user
1992 # $self->form->{'step'} equal to "my_step" because of default path_info_map_base
1993 # and $self->form->{'username'} equals "my_user" because of my_step_path_info_map
1995 The section on mapping URIs to steps has additional examples.
1997 =item post_loop (method)
1999 Ran after all of the steps in the loop have been processed (if
2000 prepare, info_complete, and finalize were true for each of the steps).
2001 If it returns a true value the navigation loop will be aborted. If it
2002 does not return true, navigation continues by then inserting the step
2003 $self->default_step and running $self->nav_loop again (recurses) to
2004 fall back to the default step.
2006 =item post_navigate (method)
2008 Called from within navigate. Called after the nav_loop has finished
2009 running but within the eval block to catch errors. Will only run if
2010 there were no errors which died during the nav_loop process.
2012 It can be disabled from running by setting the _no_post_navigate
2015 If per-step authentication is enabled and authentication fails,
2016 the post_navigate method will still be called (the post_navigate
2017 method can check the ->is_authed method to change behavior). If
2018 application level authentication is enabled and authentication
2019 fails, none of the pre_navigate, nav_loop, or post_navigate methods
2022 =item post_print (hook)
2024 A hook which occurs after the printing has taken place. Is only run
2025 if the information was not complete. Useful for cases such as
2026 printing rows of a database query after displaying a query form.
2028 =item post_step (hook)
2030 Ran at the end of the step's loop if prepare, info_complete, and
2031 finalize all returned true. Allows for cleanup. If a true value is
2032 returned, execution of navigate is returned and no more steps are
2035 =item pre_loop (method)
2037 Called right before the navigation loop is started (at the beginning
2038 of nav_loop). At this point the path is set (but could be modified).
2039 The only argument is a reference to the path array. If it returns a
2040 true value - the navigation routine is aborted.
2042 =item pre_navigate (method)
2044 Called at the very beginning of the navigate method, but within the
2045 eval block to catch errors. Called before the nav_loop method is
2046 started. If a true value is returned then navigation is skipped (the
2047 nav_loop is never started).
2049 =item pre_step (hook)
2051 Ran at the beginning of the loop before prepare, info_compelete, and
2052 finalize are called. If it returns true, execution of nav_loop is
2053 returned and no more steps are processed..
2055 =item prepare (hook)
2057 Defaults to true. A hook before checking if the info_complete is true.
2058 Intended to be used to cleanup the form data.
2060 =item prepared_print (hook)
2062 Called when any of prepare, info_complete, or finalize fail. Prepares
2063 a form hash and a fill hash to pass to print. The form hash is primarily
2064 intended for use by the templating system. The fill hash is intended
2065 to be used to fill in any html forms.
2067 =item previous_step (method)
2069 List the step previous to this one. Will return '' if there is no previous step.
2073 Take the information generated by prepared_print, format it using
2074 swap_template, fill it using fill_template and print it out using
2075 print_out. Default incarnation uses CGI::Ex::Template (a subclass of
2076 Template::Alloy) which is compatible with Template::Toolkit to do the
2077 swapping. Arguments are: step name (used to call the file_print
2078 hook), swap hashref (passed to call swap_template), and fill hashref
2079 (passed to fill_template).
2081 During the print call, the file_print hook is called which should
2082 return a filename or a scalar reference to the template content is
2084 =item print_out (hook)
2086 Called with the finished document. Should print out the appropriate headers.
2087 The default method calls $self->cgix->print_content_type and then
2090 The print_content_type is passed $self->mimetype (which defaults to
2091 $self->{'mimetype'} which defaults to 'text/html') and $self->charset
2092 (which defaults to $self->{'charset'} which defaults to '').
2094 =item ready_validate (hook)
2096 Should return true if enough information is present to run validate.
2097 Default is to look if $ENV{'REQUEST_METHOD'} is 'POST'. A common
2098 usage is to pass a common flag in the form such as 'processing' => 1
2099 and check for its presence - such as the following:
2101 sub ready_validate { shift->form->{'processing'} }
2103 Changing the behavior of ready_validate can help in making wizard type
2106 You can also use the validate_when_data hook to change the behavior of
2107 ready_validate. If valiate_when_data returns true, then
2108 ready_validate will look for keys in the form matching keys that are
2109 in hash_validation - if they exist ready_validate will be true. If
2110 there are no hash_validation keys, ready_validate uses its default
2113 =item refine_path (hook)
2115 Called at the end of nav_loop. Passed a single value indicating
2116 if there are currently more steps in the path.
2118 The default implementation returns if there are still more steps
2119 in the path. Otherwise, it calls the next_step hook and appends
2120 it to the path with the append_path method, and then calls
2121 the set_ready_validate hook and passes it 0.
2123 This allows you to simply put
2125 sub edit_next_step { '_edit_success' }
2127 In your code and it will automatically do the right thing and
2128 go to the _edit_success step.
2130 =item recurse_limit (method)
2132 Default 15. Maximum number of times to allow nav_loop to call itself.
2133 The recurse level will increase every time that ->jump is called, or if
2134 the end of the nav_loop is reached and the process tries to add the
2135 default_step and run it again.
2137 If ->jump is used often - the recurse_limit will be reached more
2138 quickly. It is safe to raise this as high as is necessary - so long
2139 as it is intentional.
2141 Often the limit is reached if a step did not have a validation hash,
2142 or if the set_ready_validate(0) method was not called once the data
2143 had been successfully validated and acted upon.
2145 =item replace_path (method)
2147 Arguments are the steps used to replace. Can be called any time.
2148 Replaces the remaining steps (if any) of the current path.
2150 =item require_auth (hook)
2152 Defaults to self->{require_auth} which defaults to undef.
2153 If called as a method and passed a single value of 1, 0, or undef it will
2154 set the value of $self->{require_auth} to that value. If set to a true
2155 value then any subsequent step will require authentication (unless its
2156 hook has been overwritten).
2158 Any of the following ways can be used to require authentication on
2165 sub require_auth { 1 }
2169 __PACKAGE__->navigate_authenticated; # instead of __PACKAGE__->navigate;
2173 __PACKAGE__->new({require_auth => 1}->navigate;
2177 sub init { shift->require_auth(1) }
2181 Because it is called as a hook, the current step is passed as the
2182 first argument. If the hook returns false, no authentication will be
2183 required on this step. If the hook returns a true, non-hashref value,
2184 authentication will be required via the get_valid_auth method. If the
2185 method returns a hashref of stepnames to require authentication on,
2186 the step will require authentication via the get_valid_auth method if
2187 the current step is in the hashref. If authentication is required and
2188 succeeds, the step will proceed. If authentication is required and
2189 fails at the step level the current step will be aborted,
2190 authentication will be asked for (the post_navigate method will still
2193 For example you could add authentication to the add, edit, and delete
2194 steps in any of the following ways:
2200 sub require_auth { {add => 1, edit => 1, delete => 1} }
2204 sub add_require_auth { 1 }
2205 sub edit_require_auth { 1 }
2206 sub delete_require_auth { 1 }
2211 my ($self, $step) = @_;
2212 return 1 if $step && $step =~ /^(add|edit|delete)$/;
2218 If however you wanted to require authentication on all but one or two methods
2219 (such as requiring authentication on all but a forgot_password step) you could do
2220 either of the following:
2227 my ($self, $step) = @_;
2228 return 0 if $step && $step eq 'forgot_password';
2229 return 1; # require auth on all other steps
2234 sub require_auth { 1 } # turn it on for all steps
2236 sub forgot_password_require_auth { 0 } # turn it off
2240 See the get_valid_auth method for what occurs should authentication be required.
2242 There is one key difference from the 2.14 version of App. In 2.14 and
2243 previous versions, the pre_navigate and post_navigate methods would
2244 not be called if require_auth returned a true non-hashref value. In
2245 version 2.15 and later, the 2.15 pre_navigate and post_navigate
2246 methods are always called - even if authentication fails. Also in 2.15
2247 and later, the method is called as a hook meaning the step is passed in.
2249 =item run_hook (method)
2251 Arguments are a hook name and the step to find the hook for. Calls
2252 the find_hook method to get a code ref which it then calls and returns
2253 the result passing any extra arguments to run_hook as arguments to the
2256 Each call to run_hook is logged in the arrayref returned by the
2257 history method. This information is summarized in the dump_history
2258 method and is useful for tracing the flow of the program.
2260 The run_hook method is part of the core of CGI::Ex::App. It allows
2261 for an intermediate layer in normal method calls. Because of
2262 run_hook, it is possible to logically override methods on a step by
2263 step basis, or override a method for all of the steps, or even to
2264 break code out into separate modules.
2266 =item run_step (hook)
2268 Runs all of the hooks specific to each step, beginning with pre_step
2269 and ending with post_step (for a full listing of steps, see the
2270 section on process flow). Called after ->morph($step) has been run.
2271 If this hook returns true, the nav_loop is exited (meaning the
2272 run_step hook displayed a printed page). If it returns false, the
2273 nav_loop continues on to run the next step.
2275 This hook performs the same base functionality as a method defined in
2276 CGI::Applications ->run_modes. The default run_step method provides
2277 much more granular control over the flow of the CGI.
2279 =item set_path (method)
2281 Arguments are the steps to set. Should be called before navigation
2282 begins. This will set the path arrayref to the passed steps.
2284 This method is not normally used.
2286 =item set_ready_validate (hook and method)
2288 Sets that the validation is ready (or not) to validate. Should set the value
2289 checked by the hook ready_validate. Has no affect if validate_when_data
2292 The following would complement the "processing" flag example given in
2293 ready_validate description:
2295 sub set_ready_validate {
2297 my ($step, $is_ready) = (@_ == 2) ? @_ : (undef, shift);
2299 $self->form->{'processing'} = 1;
2301 delete $self->form->{'processing'};
2306 Note that for this example the form key "processing" was deleted. This
2307 is so that the call to fill in any html forms won't swap in a value of
2308 zero for form elements named "processing."
2310 Also note that this method may be called as a hook as in
2312 $self->run_hook('set_ready_validate', $step, 0)
2314 $self->set_ready_validate($step, 0);
2316 Or it can take a single argument and should set the ready status
2317 regardless of the step as in:
2319 $self->set_ready_validate(0);
2323 Ran at the beginning of the loop before prepare, info_complete, and
2324 finalize are called. If it returns true, nav_loop moves on to the
2325 next step (the current step is skipped).
2327 =item stash (method)
2329 Returns a hashref that can store arbitrary user space data without
2330 worrying about overwriting the internals of the application.
2332 =item step_key (method)
2334 Should return the keyname that will be used by the default "path"
2335 method to look for in the form. Default value is 'step'.
2337 =item swap_template (hook)
2339 Takes the template and hash of variables prepared in print, and
2340 processes them through the current template engine (default engine is
2341 CGI::Ex::Template a subclass of Template::Alloy).
2343 Arguments are the template and the swap hashref. The template can be
2344 either a scalar reference to the actual content, or the filename of
2345 the content. If the filename is specified - it should be relative to
2346 template_path (which will be used to initialize INCLUDE_PATH by
2349 The default method will create a template object by calling the
2350 template_args hook and passing the returned hashref to the
2351 template_obj method. The default template_obj method returns a
2352 CGI::Ex::Template object, but could easily be swapped to use a
2353 Template::Toolkit based object. If a non-Template::Toolkit compatible
2354 object is to be used, then the swap_template hook can be overridden to
2355 use another templating engine.
2357 For example to use the HTML::Template engine you could override the swap_template
2363 my ($self, $step, $file, $swap) = @_;
2365 my $type = UNIVERSAL::isa($file, 'SCALAR') ? 'scalarref'
2366 : UNIVERSAL::isa($file, 'ARRAY') ? 'arrayref'
2367 : ref($file) ? 'filehandle'
2370 my $t = HTML::Template->new(source => $file,
2372 path => $self->template_path,
2373 die_on_bad_params => 0,
2381 As of version 2.13 of CGI::Ex::Template you could also simply do the
2382 following to parse the templates using HTML::Template::Expr syntax.
2385 return {SYNTAX => 'hte'};
2388 For a listing of the available syntaxes, see the current L<Template::Alloy> documentation.
2390 =item template_args (hook)
2392 Returns a hashref of args that will be passed to the "new" method of CGI::Ex::Template.
2393 The method is normally called from the swap_template hook. The swap_template hook
2394 will add a value for INCLUDE_PATH which is set equal to template_path, if the INCLUDE_PATH
2395 value is not already set.
2397 The returned hashref can contain any arguments that CGI::Ex::Template (a subclass of Template::Alloy)
2403 WRAPPER => 'wrappers/main_wrapper.html',
2407 See the L<Template::Alloy> documentation for a listing of all possible configuration arguments.
2409 =item template_obj (method)
2411 Called from swap_template. It is passed the result of template_args
2412 that have had a default INCLUDE_PATH added via template_path. The default
2413 implementation uses CGI::Ex::Template (a subclass of Template::Alloy)
2414 but can easily be changed to use Template::Toolkit by using code
2415 similar to the following:
2420 my ($self, $args) = @_;
2421 return Template->new($args);
2424 =item template_path (method)
2426 Defaults to $self->{'template_path'} which defaults to base_dir_abs. Used by
2427 the template_obj method.
2429 =item unmorph (method)
2431 Allows for returning an object back to its previous blessed state if
2432 the "morph" method was successful in morphing the App object. This
2433 only happens if the object was previously morphed into another object
2434 type. Before the object is re-blessed the method fixup_before_unmorph
2437 See allow_morph and morph.
2439 =item valid_steps (method)
2441 Called by the default path method. Should return a hashref of path
2442 steps that are allowed. If the current step is not found in the hash
2443 (or is not the default_step or js_step) the path method will return a
2444 single step of ->forbidden_step and run its hooks. If no hash or undef is
2445 returned, all paths are allowed (default). A key "forbidden_step"
2446 containing the step that was not valid will be placed in the stash.
2447 Often the valid_steps method does not need to be defined as arbitrary
2448 method calls are not possible with CGI::Ex::App.
2450 Any steps that begin with _ are also "not" valid for passing in via the form
2451 or path info. See the path method.
2453 Also, the pre_step, skip, prepare, and info_complete hooks allow for validating
2454 the data before running finalize.
2456 =item validate (hook)
2458 Passed the form from $self->form. Runs validation on the information
2459 contained in the passed form. Uses CGI::Ex::Validate for the default
2460 validation. Calls the hook hash_validation to load validation hashref
2461 (an empty hash means to pass validation). Should return true if the
2462 form passed validation and false otherwise. Errors are stored as a
2463 hash in $self->{hash_errors} via method add_errors and can be checked
2464 for at a later time with method has_errors (if the default validate
2467 There are many ways and types to validate the data. Please see the
2468 L<CGI::Ex::Validate> module.
2470 Upon success, it will look through all of the items which were
2471 validated, if any of them contain the keys append_path, insert_path,
2472 or replace_path, that method will be called with the value as
2473 arguments. This allows for the validation to apply redirection to the
2474 path. A validation item of:
2476 {field => 'foo', required => 1, append_path => ['bar', 'baz']}
2478 would append 'bar' and 'baz' to the path should all validation succeed.
2480 =item validate_when_data (hook)
2482 Defaults to "validate_when_data" property which defaults to false. Called
2483 during the ready_validate hook. If returns true, ready_validate will look
2484 for keys in the form matching keys that are in hash_validation - if they exist
2485 ready_validate will be true. If there are no hash_validation keys, ready_validate
2486 uses its default behavior.
2488 =item verify_user (method)
2490 Installed as a hook to CGI::Ex::App during get_valid_auth. Should return
2491 true if the user is ok. Default is to always return true. This can be
2492 used to abort early before the get_pass_by_user hook is called.
2495 my ($self, $user) = @_;
2496 return 0 if $user eq 'paul'; # don't let paul in
2497 return 1; # let anybody else in
2502 =head1 HOW DO I SET COOKIES, REDIRECT, ETC
2504 Often in your program you will want to set cookies or bounce to a differnt URL.
2505 This can be done using either the builtin CGI::Ex object or the built in
2506 CGI object. It is suggested that you only use the CGI::Ex methods as it will
2507 automatically send headers and method calls under cgi, mod_perl1, or mod_perl2.
2508 The following shows how to do basic items using the CGI::Ex object returned by
2513 =item printing content-type headers
2515 ### CGI::Ex::App prints headers for you,
2516 ### but if you are printing custom types, you can send your own
2517 $self->cgix->print_content_type;
2519 # $self->cgix->print_content_type('text/html');
2521 =item setting a cookie
2523 $self->cgix->set_cookie({
2525 -value => 'Some Value',
2530 =item redirecting to another URL
2532 $self->cgix->location_bounce("http://somewhereelse.com");
2533 $self->exit_nav_loop; # normally should do this to long jump out of navigation
2535 =item making a QUERY_STRING
2537 my $data = {foo => "bar", one => "two or three"};
2538 my $query = $self->cgix->make_form($data);
2539 # $query now equals "foo=bar&one=two%20or%20three"
2541 =item getting form parameters
2543 my $form = $self->form;
2545 In this example $form would now contain a hashref of all POST and GET parameters
2546 passed to the server. The form method calls $self->cgix->get_form
2547 which in turn uses CGI->param to parse values. Fields with multiple passed
2548 values will be in the form of an arrayref.
2550 =item getting cookies
2552 my $cookies = $self->cookies;
2554 In this example $cookies would be a hashref of all passed in cookies. The
2555 cookies method calls $self->cgix->get_cookies which in turn uses CGI->cookie
2560 See the CGI::Ex and CGI documentation for more information.
2562 =head1 COMPARISON TO OTHER APPLICATION MODULES
2564 The concepts used in CGI::Ex::App are not novel or unique. However, they
2565 are all commonly used and very useful. All application builders were
2566 built because somebody observed that there are common design patterns
2567 in CGI building. CGI::Ex::App differs in that it has found more common design
2568 patterns of CGI's than other application builders and tries to get in the way
2571 CGI::Ex::App is intended to be sub classed, and sub sub classed, and each step
2572 can choose to be sub classed or not. CGI::Ex::App tries to remain simple
2573 while still providing "more than one way to do it." It also tries to avoid
2574 making any sub classes have to call ->SUPER:: (although that is fine too).
2576 And if what you are doing on a particular is far too complicated or custom for
2577 what CGI::Ex::App provides, CGI::Ex::App makes it trivial to override all behavior.
2579 There are certainly other modules for building CGI applications. The
2580 following is a short list of other modules and how CGI::Ex::App is
2585 =item C<CGI::Application>
2587 Seemingly the most well know of application builders.
2588 CGI::Ex::App is different in that it:
2590 * Uses Template::Toolkit compatible CGI::Ex::Template (a
2591 subclass of Template::Alloy) by default.
2592 CGI::Ex::App can easily use another toolkit by simply
2593 overriding the ->swap_template method.
2594 CGI::Application uses HTML::Template.
2595 * Offers integrated data validation.
2596 CGI::Application has had custom plugins created that
2597 add some of this functionality. CGI::Ex::App has the benefit
2598 that validation is automatically available in javascript as well.
2599 * Allows the user to print at any time (so long as proper headers
2600 are sent. CGI::Application requires data to be pipelined.
2601 * Offers hooks into the various phases of each step ("mode" in
2602 CGI::Application lingo). CGI::Application provides only ->runmode
2603 which is only a dispatch.
2604 * Support for easily jumping around in navigation steps.
2605 * Support for storing some steps in another package.
2606 * Integrated authentication
2607 * Integrated form filling
2608 * Integrated PATH_INFO mapping
2610 CGI::Ex::App and CGI::Application are similar in that they take care
2611 of handling headers and they allow for calling other "runmodes" from
2612 within any given runmode. CGI::Ex::App's ->run_step is essentially
2613 equivalent to a method call defined in CGI::Application's ->run_modes.
2614 The ->run method of CGI::Application starts the application in the same
2615 manner as CGI::Ex::App's ->navigate call. Many of the hooks around
2616 CGI::Ex::App's ->run_step call are similar in nature to those provided by
2619 =item C<CGI::Prototype>
2621 There are actually many similarities. One of the nicest things about
2622 CGI::Prototype is that it is extremely short (very very short). The
2623 ->activate starts the application in the same manner as CGI::Ex::App's
2624 ->navigate call. Both use Template::Toolkit as the default template
2625 system (CGI::Ex::App uses CGI::Ex::Template which is TT compatible).
2626 CGI::Ex::App is differrent in that it:
2628 * Offers more hooks into the various phases of each step.
2629 * Support for easily jumping around in navigation steps.
2630 * Support for storing only some steps in another package.
2631 * Integrated data validation
2632 * Integrated authentication
2633 * Integrated form filling
2634 * Integrated PATH_INFO mapping
2639 =head1 SIMPLE EXTENDED EXAMPLE
2641 The following example shows the creation of a basic recipe
2642 database. It requires the use of DBD::SQLite, but that is all.
2643 Once you have configured the db_file and template_path methods
2644 of the "recipe" file, you will have a working script that
2645 does CRUD for the recipe table. The observant reader may ask - why
2646 not use Catalyst or Ruby on Rails? The observant programmer will
2647 reply that making a framework do something simple is easy, but making
2648 it do something complex is complex and any framework that tries to
2649 do the those complex things for you is too complex. CGI::Ex::App
2650 lets you write the complex logic but gives you the ability to
2651 not worry about the boring details such as template engines,
2652 or sticky forms, or cgi parameters, or data validation. Once
2653 you are setup and are running, you are only left with providing
2654 the core logic of the application.
2656 ### File: /var/www/cgi-bin/recipe (depending upon Apache configuration)
2657 ### --------------------------------------------
2660 use lib qw(/var/www/lib);
2665 ### File: /var/www/lib/Recipe.pm
2666 ### --------------------------------------------
2670 use base qw(CGI::Ex::App);
2671 use CGI::Ex::Dump qw(debug);
2676 ###------------------------------------------###
2679 # show what happened
2680 debug shift->dump_history;
2683 sub template_path { '/var/www/templates' }
2685 sub base_dir_rel { 'content' }
2687 sub db_file { '/var/www/recipe.sqlite' }
2691 if (! $self->{'dbh'}) {
2692 my $file = $self->db_file;
2693 my $exists = -e $file;
2694 $self->{'dbh'} = DBI->connect("dbi:SQLite:dbname=$file", '', '',
2696 $self->create_tables if ! $exists;
2698 return $self->{'dbh'};
2704 $self->dbh->do("CREATE TABLE recipe (
2705 id INTEGER PRIMARY KEY AUTOINCREMENT,
2706 title VARCHAR(50) NOT NULL,
2707 ingredients VARCHAR(255) NOT NULL,
2708 directions VARCHAR(255) NOT NULL,
2709 date_added VARCHAR(20) NOT NULL
2713 ###----------------------------------------------------------------###
2715 sub main_info_complete { 0 }
2717 sub main_hash_swap {
2720 my $s = "SELECT id, title, date_added
2722 ORDER BY date_added";
2723 my $data = $self->dbh->selectall_arrayref($s);
2724 my @data = map {my %h; @h{qw(id title date_added)} = @$_; \%h} @$data;
2731 ###----------------------------------------------------------------###
2733 sub add_name_step { 'edit' }
2735 sub add_hash_validation {
2737 'group order' => [qw(title ingredients directions)],
2755 my $form = $self->form;
2757 my $s = "SELECT COUNT(*) FROM recipe WHERE title = ?";
2758 my ($count) = $self->dbh->selectrow_array($s, {}, $form->{'title'});
2760 $self->add_errors(title => 'A recipe by this title already exists');
2764 $s = "INSERT INTO recipe (title, ingredients, directions, date_added)
2765 VALUES (?, ?, ?, ?)";
2766 $self->dbh->do($s, {}, $form->{'title'},
2767 $form->{'ingredients'},
2768 $form->{'directions'},
2771 $self->add_to_form(success => "Recipe added to the database");
2776 ###----------------------------------------------------------------###
2778 sub edit_skip { shift->form->{'id'} ? 0 : 1 }
2780 sub edit_hash_common {
2782 return {} if $self->ready_validate;
2784 my $sth = $self->dbh->prepare("SELECT * FROM recipe WHERE id = ?");
2785 $sth->execute($self->form->{'id'});
2786 my $hash = $sth->fetchrow_hashref;
2791 sub edit_hash_validation { shift->add_hash_validation(@_) }
2795 my $form = $self->form;
2797 my $s = "SELECT COUNT(*) FROM recipe WHERE title = ? AND id != ?";
2798 my ($count) = $self->dbh->selectrow_array($s, {}, $form->{'title'}, $form->{'id'});
2800 $self->add_errors(title => 'A recipe by this title already exists');
2804 $s = "UPDATE recipe SET title = ?, ingredients = ?, directions = ? WHERE id = ?";
2805 $self->dbh->do($s, {}, $form->{'title'},
2806 $form->{'ingredients'},
2807 $form->{'directions'},
2810 $self->add_to_form(success => "Recipe updated in the database");
2815 ###----------------------------------------------------------------###
2817 sub view_skip { shift->edit_skip(@_) }
2819 sub view_hash_common { shift->edit_hash_common(@_) }
2821 ###----------------------------------------------------------------###
2823 sub delete_skip { shift->edit_skip(@_) }
2825 sub delete_info_complete { 1 }
2827 sub delete_finalize {
2829 $self->dbh->do("DELETE FROM recipe WHERE id = ?", {}, $self->form->{'id'});
2831 $self->add_to_form(success => "Recipe deleted from the database");
2841 File: /var/www/templates/content/recipe/main.html
2842 ### --------------------------------------------
2845 <title>Recipe DB</title>
2849 [% IF success %]<span style="color:darkgreen"><h2>[% success %]</h2></span>[% END %]
2851 <table style="border:1px solid blue">
2852 <tr><th>#</th><th>Title</th><th>Date Added</th></tr>
2854 [% FOR row IN recipies %]
2856 <td>[% loop.count %].</td>
2857 <td><a href="[% script_name %]/view?id=[% row.id %]">[% row.title %]</a>
2858 (<a href="[% script_name %]/edit?id=[% row.id %]">Edit</a>)
2860 <td>[% row.date_added %]</td>
2864 <tr><td colspan=2 align=right><a href="[% script_name %]/add">Add new recipe</a></td></tr>
2870 File: /var/www/templates/content/recipe/edit.html
2871 ### --------------------------------------------
2874 <title>[% step == 'add' ? "Add" : "Edit" %] Recipe</title>
2876 <h1>[% step == 'add' ? "Add" : "Edit" %] Recipe</h1>
2878 <form method=post name=[% form_name %]>
2879 <input type=hidden name=step>
2883 [% IF step != 'add' ~%]
2885 <td><b>Id:</b></td><td>[% id %]</td></tr>
2886 <input type=hidden name=id>
2889 <td><b>Date Added:</b></td><td>[% date_added %]</td></tr>
2894 <td valign=top><b>Title:</b></td>
2895 <td><input type=text name=title>
2896 <span style='color:red' id=title_error>[% title_error %]</span></td>
2899 <td valign=top><b>Ingredients:</b></td>
2900 <td><textarea name=ingredients rows=10 cols=40 wrap=physical></textarea>
2901 <span style='color:red' id=ingredients_error>[% ingredients_error %]</span></td>
2904 <td valign=top><b>Directions:</b></td>
2905 <td><textarea name=directions rows=10 cols=40 wrap=virtual></textarea>
2906 <span style='color:red' id=directions_error>[% directions_error %]</span></td>
2909 <td colspan=2 align=right>
2910 <input type=submit value="[% step == 'add' ? 'Add' : 'Update' %]"></td>
2915 (<a href="[% script_name %]">Main Menu</a>)
2916 [% IF step != 'add' ~%]
2917 (<a href="[% script_name %]/delete?id=[% id %]">Delete this recipe</a>)
2925 File: /var/www/templates/content/recipe/view.html
2926 ### --------------------------------------------
2929 <title>[% title %] - Recipe DB</title>
2931 <h1>[% title %]</h1>
2932 <h3>Date Added: [% date_added %]</h3>
2934 <h2>Ingredients</h2>
2941 (<a href="[% script_name %]">Main Menu</a>)
2942 (<a href="[% script_name %]/edit?id=[% id %]">Edit this recipe</a>)
2946 ### --------------------------------------------
2950 The dbh method returns an SQLite dbh handle and auto creates the
2951 schema. You will normally want to use MySQL or Oracle, or Postgres
2952 and you will want your schema to NOT be auto-created.
2954 This sample uses hand rolled SQL. Class::DBI or a similar module
2955 might make this example shorter. However, more complex cases that
2956 need to involve two or three or four tables would probably be better
2957 off using the hand crafted SQL.
2959 This sample uses SQL. You could write the application to use whatever
2960 storage you want - or even to do nothing with the submitted data.
2962 We had to write our own HTML (Catalyst and Ruby on Rails do this for
2963 you). For most development work - the HTML should be in a static
2964 location so that it can be worked on by designers. It is nice that
2965 the other frameworks give you stub html - but that is all it is. It
2966 is worth about as much as copying and pasting the above examples. All
2967 worthwhile HTML will go through a non-automated design/finalization
2970 The add step used the same template as the edit step. We did
2971 this using the add_name_step hook which returned "edit". The template
2972 contains IF conditions to show different information if we were in
2973 add mode or edit mode.
2975 We reused code, validation, and templates. Code and data reuse is a
2978 The edit_hash_common returns an empty hashref if the form was ready to
2979 validate. When hash_common is called and the form is ready to
2980 validate, that means the form failed validation and is now printing
2981 out the page. To let us fall back and use the "sticky" form fields
2982 that were just submitted, we need to not provide values in the
2985 We use hash_common. Values from hash_common are used for both
2986 template swapping and filling. We could have used hash_swap and
2987 hash_fill independently.
2989 The hook main_info_complete is hard coded to 0. This basically says
2990 that we will never try and validate or finalize the main step - which
2991 is most often the case.
2993 =head1 SEPARATING STEPS INTO SEPARATE FILES
2995 It may be useful sometimes to separate some or all of the steps of an
2996 application into separate files. This is the way that CGI::Prototype
2997 works. This is useful in cases were some steps and their hooks are
2998 overly large - or are seldom used.
3000 The following modifications can be made to the previous "recipe db"
3001 example that would move the "delete" step into its own file. Similar
3002 actions can be taken to break other steps into their own file as well.
3005 ### File: /var/www/lib/Recipe.pm
3006 ### Same as before but add the following line:
3007 ### --------------------------------------------
3009 sub allow_morph { 1 }
3012 ### File: /var/www/lib/Recipe/Delete.pm
3013 ### Remove the delete_* subs from lib/Recipe.pm
3014 ### --------------------------------------------
3015 package Recipe::Delete;
3018 use base qw(Recipe);
3020 sub skip { shift->edit_skip(@_) }
3022 sub info_complete { 1 }
3026 $self->dbh->do("DELETE FROM recipe WHERE id = ?", {}, $self->form->{'id'});
3028 $self->add_to_form(success => "Recipe deleted from the database");
3035 The hooks that are called (skip, info_complete, and finalize) do not
3036 have to be prefixed with the step name because they are now in their
3037 own individual package space. However, they could still be named
3038 delete_skip, delete_info_complete, and delete_finalize and the
3039 run_hook method will find them (this would allow several steps with
3040 the same "morph_package" to still be stored in the same external
3043 The method allow_morph is passed the step that we are attempting to
3044 morph to. If allow_morph returns true every time, then it will try
3045 and require the extra packages every time that step is ran. You could
3046 limit the morphing process to run only on certain steps by using code
3047 similar to the following:
3049 sub allow_morph { return {delete => 1} }
3054 my ($self, $step) = @_;
3055 return ($step eq 'delete') ? 1 : 0;
3058 The CGI::Ex::App temporarily blesses the object into the
3059 "morph_package" for the duration of the step and re-blesses it into the
3060 original package upon exit. See the morph method and allow_morph for more
3063 =head1 RUNNING UNDER MOD_PERL
3065 The previous samples are essentially suitable for running under flat CGI,
3066 Fast CGI, or mod_perl Registry or mod_perl PerlRun type environments. It
3067 is very easy to move the previous example to be a true mod_perl handler.
3069 To convert the previous recipe example, simply add the following:
3071 ### File: /var/www/lib/Recipe.pm
3072 ### Same as before but add the following lines:
3073 ### --------------------------------------------
3081 ### File: apache2.conf - or whatever your apache conf file is.
3082 ### --------------------------------------------
3084 SetHandler perl-script
3090 Both the /cgi-bin/recipe version and the /recipe version can co-exist.
3091 One of them will be a normal cgi and the other will correctly use
3092 mod_perl hooks for headers.
3094 Setting the location to /recipe means that the $ENV{SCRIPT_NAME} will
3095 also be set to /recipe. This means that name_module method will
3096 resolve to "recipe". If a different URI location is desired such as
3097 "/my_cool_recipe" but the program is to use the same template content
3098 (in the /var/www/templates/content/recipe directory), then we would
3099 need to explicitly set the "name_module" parameter. It could be done
3100 in either of the following ways:
3102 ### File: /var/www/lib/Recipe.pm
3103 ### Same as before but add the following line:
3104 ### --------------------------------------------
3106 sub name_module { 'recipe' }
3112 $self->{'name_module'} = 'recipe';
3115 In most use cases it isn't necessary to set name_module, but it also
3116 doesn't hurt and in all cases it is more descriptive to anybody who is
3117 going to maintain the code later.
3119 =head1 ADDING AUTHENTICATION TO THE ENTIRE APPLICATION
3121 Having authentication is sometimes a good thing. To force
3122 the entire application to be authenticated (require a valid username
3123 and password before doing anything) you could do the following.
3125 ### File: /var/www/lib/Recipe.pm
3126 ### Same as before but add
3127 ### --------------------------------------------
3129 sub get_pass_by_user {
3132 my $pass = $self->lookup_and_cache_the_pass($user);
3137 ### File: /var/www/cgi-bin/recipe (depending upon Apache configuration)
3138 ### Change the line with ->navigate; to
3139 ### --------------------------------------------
3141 Recipe->navigate_authenticated;
3145 ### File: /var/www/lib/Recipe.pm
3146 ### Same as before but add
3147 ### --------------------------------------------
3149 sub require_auth { 1 }
3153 ### File: /var/www/lib/Recipe.pm
3154 ### Same as before but add
3155 ### --------------------------------------------
3157 sub init { shift->require_auth(1) }
3159 See the require_auth, get_valid_auth, and auth_args methods for more information.
3160 Also see the L<CGI::Ex::Auth> perldoc.
3162 =head1 ADDING AUTHENTICATION TO INDIVIDUAL STEPS
3164 Sometimes you may only want to have certain steps require
3165 authentication. For example, in the previous recipe example we
3166 might want to let the main and view steps be accessible to anybody,
3167 but require authentication for the add, edit, and delete steps.
3169 To do this, we would do the following to the original example (the
3170 navigation must start with ->navigate. Starting with ->navigate_authenticated
3171 will cause all steps to require validation):
3173 ### File: /var/www/lib/Recipe.pm
3174 ### Same as before but add
3175 ### --------------------------------------------
3177 sub get_pass_by_user {
3180 my $pass = $self->lookup_and_cache_the_pass($user);
3184 sub require_auth { {add => 1, edit => 1, delete => 1} }
3186 We could also enable authentication by using individual hooks as in:
3188 sub add_require_auth { 1 }
3189 sub edit_require_auth { 1 }
3190 sub delete_require_auth { 1 }
3192 Or we could require authentication on everything - but let a few steps in:
3194 sub require_auth { 1 } # turn authentication on for all
3195 sub main_require_auth { 0 } # turn it off for main and view
3196 sub view_require_auth { 0 }
3198 That's it. The add, edit, and delete steps will now require authentication.
3199 See the require_auth, get_valid_auth, and auth_args methods for more information.
3200 Also see the L<CGI::Ex::Auth> perldoc.
3204 The following corporation and individuals contributed in some part to
3205 the original versions.
3207 Bizhosting.com - giving a problem that fit basic design patterns.
3209 Earl Cahill - pushing the idea of more generic frameworks.
3211 Adam Erickson - design feedback, bugfixing, feature suggestions.
3213 James Lance - design feedback, bugfixing, feature suggestions.
3215 Krassimir Berov - feedback and some warnings issues with POD examples.
3219 This module may be distributed under the same terms as Perl itself.
3223 Paul Seamons <perl at seamons dot com>