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
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 # returns false from info_complete if ! ready_validate
260 ->validate (hook - uses CGI::Ex::Validate to validate form info)
261 ->hash_validation (hook)
263 ->vob_path (defaults to template_path)
268 # returns true if validate is true or if nothing to validate
270 ->finalize (hook - defaults to true - ran if prepare and info_complete were true)
272 if ! ->prepare || ! ->info_complete || ! ->finalize {
280 # merge form, base, common, and fill into merged fill
281 # merge form, base, common, swap, and errors into merged swap
282 ->print (hook - passed current step, merged swap hash, and merged fill)
283 ->file_print (hook - uses base_dir_rel, name_module, name_step, ext_print)
284 ->swap_template (hook - processes the file with CGI::Ex::Template)
285 ->template_args (hook - passed to CGI::Ex::Template->new)
286 ->fill_template (hook - fills the any forms with CGI::Ex::Fill)
287 ->fill_args (hook - passed to CGI::Ex::Fill::fill)
288 ->print_out (hook - print headers and the content to STDOUT)
290 ->post_print (hook - used for anything after the print process)
292 # return true to exit from nav_loop
296 # exits nav_loop if true
300 It is important to learn the function and placement of each of the
301 hooks in the process flow in order to make the most of CGI::Ex::App.
302 It is enough to begin by learning a few common hooks - such as
303 hash_validation, hash_swap, and finalize, and then learn about other
304 hooks as needs arise. Sometimes, it is enough to simply override the
305 run_step hook and take care of processing the entire step yourself.
307 Because of the hook based system, and because CGI::Ex::App uses
308 sensible defaults, it is very easy to override a little or a lot which
309 ends up giving the developer a lot of flexibility.
311 Additionally, it should be possible to use CGI::Ex::App with the other
312 frameworks such as CGI::Application or CGI::Prototype. For these you
313 could simple let each "runmode" call the run_step hook of CGI::Ex::App
314 and you will instantly get all of the common process flow for free.
316 =head1 MAPPING URI TO STEP
318 The default out of the box configuration will map URIs to steps as follows:
320 # Assuming /cgi-bin/my_app is the program being run
325 WHY: No other information is passed. The path method is
326 called which eventually calls ->default_step which
329 URI: /cgi-bin/my_app?foo=bar
332 WHY: Same as previous example except that QUERY_STRING
333 information was passed and placed in form.
335 URI: /cgi-bin/my_app?step=my_step
337 FORM: {step => "my_step"}
338 WHY: The path method is called which looks in $self->form
339 for the key ->step_key (which defaults to "step").
341 URI: /cgi-bin/my_app?step=my_step&foo=bar
343 FORM: {foo => "bar", step => "my_step"}
344 WHY: Same as before but another parameter was passed.
346 URI: /cgi-bin/my_app/my_step
348 FORM: {step => "my_step"}
349 WHY: The path method is called which called path_info_map_base
350 which matched $ENV{'PATH_INFO'} using the default regex
351 of qr{^/(\w+)$} and place the result in
352 $self->form->{$self->step_key}. Path then looks in
353 $self->form->{$self->step_key} for the initial step. See
354 the path_info_map_base method for more information.
356 URI: /cgi-bin/my_app/my_step?foo=bar
358 FORM: {foo => "bar", step => "my_step"}
359 WHY: Same as before but other parameters were passed.
361 URI: /cgi-bin/my_app/my_step?step=other_step
363 FORM: {step => "other_step"}
364 WHY: The same procedure took place, but when the PATH_INFO
365 string was matched, the form key "step" already existed
366 and was not replaced by the value from PATH_INFO.
368 The remaining examples in this section are based on the assumption
369 that the following method is installed in your script.
371 sub my_step_path_info_map {
373 [qr{^/\w+/(\w+)/(\d+)$}, 'foo', 'id'],
374 [qr{^/\w+/(\w+)$}, 'foo'],
375 [qr{^/\w+/(.+)$}, 'anything_else'],
379 URI: /cgi-bin/my_app/my_step/bar
382 WHY: The step was matched as in previous examples using
383 path_info_map_base. However, the form key "foo"
384 was set to "bar" because the second regex returned
385 by the path_info_map hook matched the PATH_INFO string
386 and the corresponding matched value was placed into
387 the form using the keys specified following the regex.
389 URI: /cgi-bin/my_app/my_step/bar/1234
391 FORM: {foo => "bar", id => "1234"}
392 WHY: Same as the previous example, except that the first
393 regex matched the string. The first regex had two
394 match groups and two form keys specified. Note that
395 it is important to order your match regexes in the
396 order that will match the most data. The third regex
397 would also match this PATH_INFO.
399 URI: /cgi-bin/my_app/my_step/some/other/type/of/data
401 FORM: {anything_else => 'some/other/type/of/data'}
402 WHY: Same as the previous example, except that the third
405 URI: /cgi-bin/my_app/my_step/bar?bling=blang
407 FORM: {foo => "bar", bling => "blang"}
408 WHY: Same as the first sample, but additional QUERY_STRING
409 information was passed.
411 URI: /cgi-bin/my_app/my_step/one%20two?bar=three%20four
413 FORM: {anything_else => "one two", bar => "three four"}
414 WHY: The third path_info_map regex matched. Note that the
415 %20 in bar was unescaped by CGI::param, but the %20
416 in anything_else was unescaped by Apache. If you are
417 not using Apache, this behavior may vary. CGI::Ex::App
418 doesn't decode parameters mapped from PATH_INFO.
420 See the path method for more information about finding the initial step
423 The form method calls CGI::Ex::form which uses CGI::param to retrieve
424 GET and POST parameters. See the form method for more information on
425 how GET and POST parameters are parsed.
427 See the path_info_map_base method, and path_info_map hook for more information
428 on how the path_info maps function.
430 Using the following code is very useful for determing what hooks have
433 use CGI::Ex::Dump qw(debug);
437 debug $self->dump_history, $self->form;
440 =head1 ADDING DATA VALIDATION TO A STEP
442 CGI::Ex::App uses CGI::Ex::Validate for its data validation. See CGI::Ex::Validate
443 for more information about the many ways you can validate your data.
445 The default hash_validation hook returns an empty hashref. This means that passed
446 in data is all valid and the script will automatically call the step's finalize method.
448 The following shows how to add some contrived validation to a step called "my_step".
450 sub my_step_hash_validation {
454 match => 'm/^(\w+)$/',
455 match_error => 'The $field field may only contain word characters',
463 validate_if => 'password',
464 equals => 'password',
468 enum => [qw(animal vegetable mineral)],
473 The step will continue to display the html form until all of the fields pass
476 See the hash_validation hook and validate hook for more information about how
479 =head1 ADDING JAVASCRIPT DATA VALIDATION TO A STEP
481 You must first provide a hash_validation hook as explained in the previous section.
483 Once you have a hash_validation hook, you would place the following tags
484 into your HTML template.
486 <form name="[% form_name %]" method="post">
491 The "form_name" swap-in places a name on the form that the javascript returned by
492 the js_validation swap-in will be able to find and check for validity.
494 See the hash_validation, js_validation, and form_name hooks for more information.
496 Also, CGI::Ex::validate.js allows for inline errors in addition to or in replacement
497 of an alert message. To use inline errors, you must provide an element in your
498 HTML document where this inline message can be placed. The common way to do it is as
501 <input type="text" name="username"><br>
502 <span class="error" id="username_error">[% username_error %]</span>
504 The span around the error allows for the error css class and it provides a location
505 that the Javascript validation can populate with errors. The [% username_error %] provides
506 a location for errors generated on the server side to be swapped in. If there was no error
507 the [% username_error %] tag would default to "".
509 =head1 ADDING ADDITIONAL TEMPLATE VARIABLES
511 All variables returned by the hash_base, hash_common, hash_form, hash_swap, and
512 hash_errors hooks are available for swapping in templates.
514 The following shows how to add variables using the hash_swap hook on the step "main".
519 choices => [qw(one two three)],
520 "warn" => sub { warn @_ },
524 You could also return the fields from the hash_common hook and they
525 would be available in both the template swapping as well as form
528 See the hash_base, hash_common, hash_form, hash_swap, hash_errors,
529 swap_template, and template_args hooks for more information.
531 The default template engine used is CGI::Ex::Template which is now a subclass
532 of Template::Alloy. The default interface used is TT which is the
533 Template::Toolkit interface. Template::Alloy allows for using TT documents,
534 HTML::Template documents, HTML::Template::Expr documents, Text::Tmpl documents,
535 or Velocity (VTL) documents. See the L<Template::Alloy> documentation
536 for more information.
538 =head1 ADDING ADDITIONAL FORM FILL VARIABLES
540 All variables returned by the hash_base, hash_common, hash_form, and hash_fill hooks
541 are available for filling html fields in on templates.
543 The following shows how to add variables using the hash_fill hook on the step "main".
548 choices => [qw(one two three)],
552 You could also return the fields from the hash_common hook and they would be available
553 in both the form filling as well as in the template swapping.
555 See the hash_base, hash_common, hash_form, hash_swap, hash_errors, fill_template, and
556 fill_args hooks for more information.
558 The default form filler is CGI::Ex::Fill which is similar to HTML::FillInForm but
559 has several benefits. See the CGI::Ex::Fill module for the available options.
561 =head1 FINDING TEMPLATES AND VALIDATION FILES
563 CGI::Ex::App tries to help your applications use a good template directory layout, but allows
564 for you to override everything.
566 External template files are used for storing your html templates and
567 for storing your validation files (if you use externally stored
570 The default file_print hook will look for content on your file system,
571 but it can also be completely overridden to return a reference to a
572 scalar containing the contents of your file (beginning with version 2.14
573 string references can be cached which makes templates passed this way
574 "first class" citizens). Actually it can return
575 anything that Template::Alloy (Template::Toolkit compatible) will
576 treat as input. This templated html is displayed to the user during
577 any step that enters the "print" phase.
579 Similarly the default file_val hook will look for a validation file on
580 the file system, but it too can return a reference to a scalar
581 containing the contents of a validation file. It may actually return
582 anything that the CGI::Ex::Validate get_validation method is able to
583 understand. This validation is used by the default "info_complete"
584 method for verifying if the submitted information passes its specific
585 checks. A more common way of inlining validation is to return a
586 validation hash from a hash_validation hook override.
588 If the default file_print and file_val hooks are used, the following methods
589 are employed for finding templates and validation files on your filesystem (they
590 are also documented more in the HOOKS AND METHODS section.
596 Absolute path or arrayref of paths to the base templates directory. Defaults to
597 base_dir_abs which defaults to ['.'].
601 Relative path inside of the template_path directory where content can be found. Default "".
605 Directory inside of base_dir_rel where files for the current CGI (module) will be
606 stored. Default value is $ENV{SCRIPT_NAME} with path and extension removed.
610 Used with ext_print and ext_val for creating the filename that will be looked for
611 inside of the name_module directory. Default value is the current step.
613 =item ext_print and ext_val
615 Filename extensions added to name_step to create the filename looked for
616 inside of the name_module directory. Default is "html" for ext_print and "val"
621 It may be easier to understand the usage of each of these methods by showing
622 a contrived example. The following is a hypothetical layout for your templates:
624 /home/user/templates/
625 /home/user/templates/chunks/
626 /home/user/templates/wrappers/
627 /home/user/templates/content/
628 /home/user/templates/content/my_app/
629 /home/user/templates/content/my_app/main.html
630 /home/user/templates/content/my_app/step1.html
631 /home/user/templates/content/my_app/step1.val
632 /home/user/templates/content/another_cgi/main.html
634 In this example we would most likely set values as follows:
636 template_path /home/user/templates
640 The name_module method defaults to the name of the running program, but
641 with the path and extension removed. So if we were running
642 /cgi-bin/my_app.pl, /cgi-bin/my_app, or /anypath/my_app, then
643 name_module would default to "my_app" and we wouldn't have to
644 hard code the value. Often it is wise to set the value anyway so
645 that we can change the name of the cgi script without effecting
646 where template content should be stored.
648 Continuing with the example and assuming that name of the step that
649 the user has requested is "step1" then the following values would be
652 template_path /home/user/templates
659 file_print content/my_app/step1.html
660 file_val /home/user/templates/content/my_app/step1.val
662 The call to the template engine would look something like
665 my $t = $self->template_obj({
666 INCLUDE_PATH => $self->template_path, # defaults to base_dir_abs
669 $t->process($self->file_print($step), \%vars);
671 The template engine would then look for the relative file
672 inside of the absolute paths (from template_path).
674 The call to the validation engine would pass the absolute
675 filename that is returned by file_val.
677 The name_module and name_step methods can return filenames with
678 additional directories included. The previous example could
679 also have been setup using the following values:
681 template_path /home/user/templates
683 name_module content/my_app
685 In this case the same values would be returned for the file_print and file_val hooks
686 as were returned in the previous setup.
688 =head1 SYNOPSIS (A LONG "SYNOPSIS")
690 This example script would most likely be in the form of a cgi, accessible via
691 the path http://yourhost.com/cgi-bin/my_app (or however you do CGIs on
692 your system. About the best way to get started is to paste the following
693 code into a cgi script (such as cgi-bin/my_app) and try it out. A detailed
694 walk-through follows in the next section. There is also a longer recipe
695 database example at the end of this document that covers other topics including
696 making your module a mod_perl handler.
698 ### File: /var/www/cgi-bin/my_app (depending upon Apache configuration)
699 ### --------------------------------------------
703 use base qw(CGI::Ex::App);
704 use CGI::Ex::Dump qw(debug);
706 __PACKAGE__->navigate;
708 # my $obj = __PACKAGE__->new;
713 ###------------------------------------------###
717 debug shift->dump_history;
720 sub main_hash_validation {
722 'general no_alert' => 1,
723 'general no_confirm' => 1,
724 'group order' => [qw(username password password2)],
730 match_error => 'You may only use letters and numbers.',
737 equals => 'password',
742 sub main_file_print {
743 # reference to string means ref to content
744 # non-reference means filename
745 return \ "<h1>Main Step</h1>
746 <form method=post name=[% form_name %]>
747 <input type=hidden name=step>
750 <td><b>Username:</b></td>
751 <td><input type=text name=username><span style='color:red' id=username_error>[% username_error %]</span></td>
753 <td><b>Password:</b></td>
754 <td><input type=text name=password><span style='color:red' id=password_error>[% password_error %]</span></td>
756 <td><b>Verify Password:</b></td>
757 <td><input type=text name=password2><span style='color:red' id=password2_error>[% password2_error %]</span></td>
759 <tr><td colspan=2 align=right><input type=submit></td></tr>
769 if ($self->form->{'username'} eq 'bar') {
770 $self->add_errors(username => 'A trivial check to say the username cannot be "bar"');
774 debug $self->form, "Do something useful with form here in the finalize hook.";
777 $self->add_to_swap({success_msg => "We did something"});
778 $self->append_path('success');
779 $self->set_ready_validate(0);
783 sub success_file_print {
784 \ "<div style=background:lightblue>
785 <h1>Success Step - [% success_msg %]</h1>
786 Username: <b>[% username %]</b><br>
787 Password: <b>[% password %]</b><br>
794 Note: This example would be considerably shorter if the html file
795 (file_print) and the validation file (file_val) had been placed in
796 separate files. Though CGI::Ex::App will work "out of the box" as
797 shown it is more probable that any platform using it will customize
798 the various hooks to their own tastes (for example, switching print to
799 use a templating system other than Template::Alloy).
801 =head1 SYNOPSIS STEP BY STEP
803 This section goes step by step over the previous example.
805 Well - we start out with the customary CGI introduction.
810 use base qw(CGI::Ex::App);
811 use CGI::Ex::Dump qw(debug);
813 Note: the "use base" is not normally used in the "main" portion of a script.
814 It does allow us to just do __PACKAGE__->navigate.
816 Now we need to invoke the process:
818 __PACKAGE__->navigate;
820 # my $obj = __PACKAGE__->new;
824 Note: the "exit" isn't necessary - but it is kind of nice to infer
825 that process flow doesn't go beyond the ->navigate call.
827 The navigate routine is now going to try and "run" through a series of
828 steps. Navigate will call the ->path method which should return an
829 arrayref containing the valid steps. By default, if path method has
830 not been overridden, the path method will default first to the step
831 found in form key named ->step_name, then it will fall to the contents
832 of $ENV{'PATH_INFO'}. If navigation runs out of steps to run it will
833 run the step found in ->default_step which defaults to 'main'. So the
834 URI '/cgi-bin/my_app' would run the step 'main' first by default. The
835 URI '/cgi-bin/my_app?step=foo' would run the step 'foo' first. The
836 URI '/cgi-bin/my_app/bar' would run the step 'bar' first.
838 CGI::Ex::App allows for running steps in a preset path or each step may
839 choose the next step that should follow. The navigate
840 method will go through one step of the path at a time and see if it is
841 completed (various methods determine the definition of "completed").
842 This preset type of path can also be automated using the CGI::Path
843 module. Rather than using a preset path, CGI::Ex::App also has
844 methods that allow for dynamic changing of the path, so that each step
845 can determine which step to do next (see the jump, append_path,
846 insert_path, and replace_path methods).
848 During development it would be nice to see what happened during the
849 course of our navigation. This is stored in the arrayref contained in
850 ->history. There is a method that is called after all of the navigation
851 has taken place called "post_navigate". This chunk will display history after we
852 have printed the content.
855 debug shift->dump_history;
856 } # show what happened
858 Ok. Finally we are looking at the methods used by each step of the path. The
859 hook mechanism of CGI::Ex::App will look first for a method ${step}_${hook_name}
860 called before falling back to the method named $hook_name. Internally in the
861 code there is a call that looks like $self->run_hook('hash_validation', $step). In
862 this case the step is main. The dispatch mechanism finds our method at the following
865 sub main_hash_validation { ... }
867 The process flow will see if the data is ready to validate. Once it is ready
868 (usually when the user presses the submit button) the data will be validated. The
869 hash_validation hook is intended to describe the data and will be tested
870 using CGI::Ex::Validate. See the CGI::Ex::Validate perldoc for more
871 information about the many types of validation available.
873 sub main_file_print { ... }
875 The navigation process will see if user submitted information (the form)
876 is ready for validation. If not, or if validation fails, the step needs to
877 be printed. Eventually the file_print hook is called. This hook should
878 return either the filename of the template to be printed, or a reference
879 to the actual template content. In this example we return a reference
880 to the content to be printed (this is useful for prototyping applications
881 and is also fine in real world use - but generally production applications
882 use external html templates).
884 A few things to note about the template:
886 First, we add a hidden form field called step. This will be filled in
887 automatically at a later point with the current step we are on.
889 We provide locations to swap in inline errors.
891 <span style="color:red" id="username_error">[% username_error %]</span>
893 As part of the error html we name each span with the name of the error. This
894 will allow for us to have Javascript update the error spots when the javascript
897 At the very end we add the TT variable [% js_validation %]. This swap in is
898 provided by the default hash_base hook and will provide for form data to be
899 validated using javascript.
901 Once the process flow has deemed that the data is validated, it then calls
902 the finalize hook. Finalize is where the bulk of operations should go.
903 We'll look at it more in depth.
907 my $form = $self->form;
909 At this point, all of the validated data is in the $form hashref.
911 if ($form->{'username'} eq 'bar') {
912 $self->add_errors(username => 'A trivial check to say the username cannot be "bar"');
916 It is most likely that though the data is of the correct type and formatting,
917 it still isn't completely correct. This previous section shows a hard coded
918 test to see if the username was 'bar'. If it was then an appropriate error will
919 be set, the routine returns 0 and the run_step process knows that it needs to
920 redisplay the form page for this step. The username_error will be shown inline.
921 The program could do more complex things such as checking to see if the username
922 was already taken in a database.
924 debug $form, "Do something useful with form here in the finalize hook.";
926 This debug $form piece is simply a place holder. It is here that the program would
927 do something useful such as add the information to a database.
930 $self->add_to_swap({success_msg => "We did something"});
932 Now that we have finished finalize, we add a message that will be passed to the template
935 $self->append_path('success');
936 $self->set_ready_validate(0);
938 The program now needs to move on to the next step. In this case we want to
939 follow with a page that informs us we succeeded. So, we append a step named "success".
940 We also call set_ready_validate(0) to inform the navigation control that the
941 form is no longer ready to validate - which will cause the success page to
942 print without trying to validate the data. It is normally a good idea
943 to set this as leaving the engine in a "ready to validate" state can result
944 in an recursive loop (that will be caught).
949 We then return 1 which tells the engine that we completed this step successfully
950 and it needs to move on to the next step.
952 Finally we run the "success" step because we told it to. That step isn't
953 ready to validate so it prints out the template page.
955 For more of a real world example, it would be good to read the sample recipe db
956 application included at the end of this document.
958 =head1 AVAILABLE METHODS / HOOKS
960 CGI::Ex::App's dispatch system works on the principles of hooks (which
961 are essentially glorified method lookups). When the run_hook method
962 is called, CGI::Ex::App will look for a corresponding method call for
963 that hook for the current step name. It is perhaps easier to show than
966 If we are calling the "print" hook for the step "edit" we would call
969 $self->run_hook('print', 'edit', $template, \%swap, \%fill);
971 This would first look for a method named "edit_print". If it is unable to
972 find a method by that name, it will look for a method named "print". If it
973 is unable to find this method - it will die.
975 If allow_morph is set to true, the same methods are searched for but it becomes
976 possible to move some of those methods into an external package.
978 See the discussions under the methods named "find_hook" and "run_hook" for more details.
980 The following is the alphabetical list of methods and hooks.
984 =item allow_morph (method)
986 Should return true if this step is allowed to "morph" the current App
987 object into another package. Default is false. It is passed a single
988 argument of the current step. For more granularity, if true value is
989 a hash, the step being morphed to must be in the hash.
991 To enable morphing for all steps, add the following:
993 sub allow_morph { 1 }
995 To enable morph on specific steps, do either of the following:
1007 my ($self, $step) = @_;
1008 return $step =~ /^(edit|delete)$/;
1011 See the morph "hook" for more information.
1013 =item allow_nested_morph (method)
1015 Similar to the allow_morph hook, but allows for one more level of morphing.
1016 This is useful in cases where the base class was morphed early on, or
1017 if a step needs to call a sub-step but morph first.
1019 See the allow_morph and the morph method for more information.
1021 Should return a boolean value or hash of allowed steps - just as the
1022 allow_morph method does.
1024 =item append_path (method)
1026 Arguments are the steps to append. Can be called any time. Adds more
1027 steps to the end of the current path.
1029 =item auth_args (method)
1031 Should return a hashref that will be passed to the new method of CGI::Ex::Auth.
1032 It is augmented with arguments that integrate it into CGI::Ex::App.
1034 See the get_valid_auth method and the CGI::Ex::Auth documentation.
1038 login_header => '<h1>My login header</h1>',
1039 login_footer => '[% TRY %][% INCLUDE login/login_footer.htm %][% CATCH %]<!-- [% error %] -->[% END %]',
1040 secure_hash_keys => [qw(aaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbb ccccccccccccccccccccccc 2222222222222)],
1041 # use_blowfish => 'my_blowfish_key',
1045 =item auth_data (method)
1047 Contains authentication data stored during the get_valid_auth method.
1048 The data is normally blessed into the CGI::Ex::Auth::Data package which
1049 evaluates to false if there was an error and true if the authentication
1050 was successful - so this data can be defined but false.
1052 See the get_valid_auth method.
1054 =item base_dir_abs (method)
1056 Used as the absolute base directory to find template, validation and conf files.
1057 It may return a single value or an arrayref of values, or a coderef that
1058 returns an arrayref or coderef of values. You may pass base_dir_abs
1059 as a parameter in the arguments passed to the "new" method.
1061 Default value is ['.'].
1063 For example, to pass multiple paths, you would use something
1064 similar to the following:
1067 return ['/my/path/one', '/some/other/path'];
1070 The base_dir_abs value is used by template_path along with the
1071 base_dir_rel, name_module, name_step, ext_print and ext_values for
1072 determining the values returned by the default file_print and file_val
1073 hooks. See those methods for further discussion.
1075 See the section on FINDING TEMPLATES for further discussion.
1077 The base_dir_abs method is also used as the default value for conf_path and vob_path.
1079 =item base_dir_rel (method)
1081 Added as a relative base directory to content under the base_dir_abs directory.
1083 Default value is "".
1085 The template_path method is used as top level where template includes may
1086 pull from, while the base_dir_rel is directory relative to the template_path
1087 where the content files will be stored.
1089 A value for base_dir_rel may passed as a parameter in the arguments passed
1092 See the template_path and base_dir_abs methods for more discussion.
1094 See the section on FINDING TEMPLATES for further discussion.
1096 =item cleanup_user (method)
1098 Used as a hook during get_valid_auth. Allows for cleaning
1099 up the username. See the get_valid_auth method.
1102 my ($self, $user) = @_;
1106 =item clear_app (method)
1108 If the same CGI::Ex::App based object is used to run multiple
1109 navigate sessions, the clear_app method should be called which
1110 will attempt to clear as much session information as it can.
1111 The following items will be cleared:
1121 _morph_lineage_start_index
1130 Used by default in init_from_conf if load_conf returns true.
1131 Will try to read the file returned by the conf_file method
1132 using the object returned by conf_obj using that object's read
1133 method. If conf_validation returns a non-empty hashref, the
1134 conf hash will be validated using $self->vob->validate (see the
1137 This method may be used for other purposes as well (including when
1138 load_conf is false)..
1140 Caches results in $self->{'conf'}.
1142 =item conf_file (method)
1144 Used by conf for finding the configuration file to load. Defaults
1145 to $self->{'conf_file'} which defaults $self->name_module with the extention
1146 returned by $self->conf_ext added on. For example, if name_module
1147 returns "my_app" and conf_ext returns "ini" the value returned will
1150 The value returned can absolute. If the value will be searched for
1151 in the paths passed to conf_obj.
1153 The conf_ext may be any of those extentions understood by CGI::Ex::Conf.
1157 Used by the default conf_file method. Defaults to $self->{'conf_ext'} which
1158 defaults to 'pl' meaning that the read configuration file should return a
1163 Used by the conf method to load the file returned by conf_file. Defaults
1164 to conf_obj which defaults to loading args from conf_args, adding in paths
1165 returned by conf_path, and calling CGI::Ex::Conf->new.
1167 Any object that provides a read method that returns a hashref can be used.
1171 Defaults to $self->{'conf_path'} which defaults to base_dir_abs. Should be
1172 a path or an arrayref of paths to look the configuration file returned by
1173 conf_file when that file is not absolute.
1179 Defaults to $self->{'conf_args'} which defaults to {}. Will have
1180 paths => $self->conf_path added before passing to CGI::Ex::Conf->new.
1182 =item conf_validation
1184 Used by default conf method.
1185 Defaults to an empty hashref. If non-empty hashref is passed, the
1186 hashref returned by conf_obj->read will be validated using the hashref
1187 returned by conf_validation.
1189 =item current_step (method)
1191 Returns the current step that the nav_loop is functioning on.
1193 =item default_step (method)
1195 Step to show if the path runs out of steps. Default value is the
1196 'default_step' property which defaults to 'main'.
1198 If nav_loop runs of the end of the path (runs out of steps), this
1199 method is called, the step is added to the path, and nav_loop calls
1202 =item destroy (method)
1204 Called at the end of navigate after all other actions have run. Can
1205 be used for undoing things done in the ->init method called during
1208 =item dump_history (method)
1210 Show simplified trace information of which steps were called, the
1211 order they were called in, the time they took to run, and a brief list
1212 of the output (to see the full response returned by each hook, pass a
1213 true value as the only argument to dump_history -
1214 $self->dump_history(1)). Indentation is also applied to show which
1215 hooks called other hooks.
1218 The first line shows the amount of time elapsed for the entire
1219 navigate execution. Subsequent lines contain:
1221 Step - the name of the current step.
1222 Hook - the name of the hook being called.
1223 Found - the name of the method that was found.
1224 Time - the total elapsed seconds that method took to run.
1225 Output - the response of the hook - shown in shortened form.
1227 Note - to get full output responses - pass a true value to
1228 dump_history - or just call ->history. Times displayed are to 5
1229 decimal places - this accuracy can only be provided if the Time::HiRes
1230 module is installed on your system (it will only be used if installed).
1232 It is usually best to print this history during the post_navigate
1233 method as in the following:
1235 use CGI::Ex::Dump qw(debug);
1236 sub post_navigate { debug shift->dump_history }
1238 The following is a sample output of dump_history called from the
1239 sample recipe application at the end of this document. The step
1242 debug: admin/Recipe.pm line 14
1243 shift->dump_history = [
1245 "view - require_auth - require_auth - 0.00001 - 0",
1246 "view - run_step - run_step - 0.00488 - 1",
1247 " view - pre_step - pre_step - 0.00003 - 0",
1248 " view - skip - view_skip - 0.00004 - 0",
1249 " view - prepare - prepare - 0.00003 - 1",
1250 " view - info_complete - info_complete - 0.00010 - 0",
1251 " view - ready_validate - ready_validate - 0.00004 - 0",
1252 " view - prepared_print - prepared_print - 0.00441 - 1",
1253 " view - hash_base - hash_base - 0.00009 - HASH(0x84ea6ac)",
1254 " view - hash_common - view_hash_common - 0.00148 - HASH(0x8310a20)",
1255 " view - hash_form - hash_form - 0.00004 - HASH(0x84eaa78)",
1256 " view - hash_fill - hash_fill - 0.00003 - {}",
1257 " view - hash_swap - hash_swap - 0.00003 - {}",
1258 " view - hash_errors - hash_errors - 0.00003 - {}",
1259 " view - print - print - 0.00236 - 1",
1260 " view - file_print - file_print - 0.00024 - recipe/view.html",
1261 " view - name_module - name_module - 0.00007 - recipe",
1262 " view - name_step - name_step - 0.00004 - view",
1263 " view - swap_template - swap_template - 0.00161 - <html> ...",
1264 " view - template_args - template_args - 0.00008 - HASH(0x865abf8)",
1265 " view - fill_template - fill_template - 0.00018 - 1",
1266 " view - fill_args - fill_args - 0.00003 - {}",
1267 " view - print_out - print_out - 0.00015 - 1",
1268 " view - post_print - post_print - 0.00003 - 0"
1271 =item error_step (method)
1273 Defaults to "__error". The name of a step to run should a dying error
1274 be caught by the default handle_error method. See the handle_error method.
1276 =item exit_nav_loop (method)
1278 This method should not normally used but there is no problem with
1279 using it on a regular basis. Essentially it is a "goto" that allows
1280 for a long jump to the end of all nav_loops (even if they are
1281 recursively nested). This effectively short circuits all remaining
1282 hooks for the current and remaining steps. It is used to allow the
1283 ->jump functionality. If the application has morphed, it will be
1284 unmorphed before returning. Also - the post_navigate method will
1287 =item ext_print (method)
1289 Added as suffix to "name_step" during the default file_print hook.
1291 Default value is 'html'.
1293 For example, if name_step returns "foo" and ext_print returns "html"
1294 then the file "foo.html" will be searched for.
1296 See the section on FINDING TEMPLATES for further discussion.
1298 =item ext_val (method)
1300 Added as suffix to "name_step" during the default file_val hook.
1302 Default value is 'val'.
1304 For example, if name_step returns "foo" and ext_val returns "val"
1305 then the file "foo.val" will be searched for.
1307 See the section on FINDING TEMPLATES for further discussion.
1309 =item fill_args (hook)
1311 Returns a hashref of args that will be passed to the CGI::Ex::Fill::fill.
1312 It is augmented with the template to swap and the fill hash. This
1313 could be useful if you needed to only swap a particular form on the template
1314 page. Arguments are passed directly to the fill function.
1316 sub fill_args { {target => 'my_form'} }
1318 =item fill_template (hook)
1320 Arguments are a template and a hashref. Takes the template that was
1321 prepared using swap_template, and swaps html form fields using the
1322 passed hashref. Overriding this method can control the fill behavior.
1324 Calls the fill_args hook prior to calling CGI::Ex::Fill::fill
1326 =item file_print (hook)
1328 Returns a filename of the content to be used in the default print
1329 hook. Adds method base_dir_rel to hook name_module, and name_step and
1330 adds on the default file extension found in $self->ext_print which
1331 defaults to the property $self->{ext_print} which will default to
1332 ".html". Should return a filename relative to template_path that can be
1333 swapped using Template::Alloy, or should be a scalar reference to
1334 the template content that can be swapped. This will be used by the
1337 sub template_path { '/var/www/templates' }
1338 sub base_dir_rel { 'content' }
1339 sub name_module { 'recipe' }
1340 sub ext_print { 'html' } # default
1342 # ->file_print('this_step')
1343 # would return 'content/recipe/this_step.html'
1344 # the template engine would look in '/var/www/templates'
1345 # for a file by that name
1347 It may also return a reference to a string containing the html template.
1348 This is useful for prototyping applications and/or keeping all of
1349 the data for the application in a single location.
1351 =item file_val (hook)
1353 Returns a filename containing the validation. Performs the same as
1354 file_print, but uses ext_val to get the extension, and it adds
1355 vob_path (which defaults to template_path which defaults to
1356 base_dir_abs) onto the returned value (file_print is relative to
1357 template_path, while file_val is fully qualified with vob_path). If
1358 vob_path returns an arrayref of paths, then each path is checked for
1359 the existence of the file.
1361 The file should be readable by CGI::Ex::Validate::get_validation.
1363 This hook is only necessary if the hash_validation hook has not been
1366 This method an also return a hashref containing the validation - but
1367 then you may have wanted to override the hash_validation hook.
1369 =item finalize (hook)
1371 Defaults to true. Used to do whatever needs to be done with the data once
1372 prepare has returned true and info_complete has returned true. On failure
1373 the print operations are ran. On success navigation moves on to the next
1376 This is normally were there core logic of a script will occur (such as
1377 adding to a database, or updating a record). At this point, the data
1378 should be validated. It is possible to do additional validation
1379 and return errors using code such as the following.
1381 if (! $user_is_unique) {
1382 $self->add_errors(username => 'The username was already used');
1386 =item find_hook (method)
1388 Called by run_hook. Arguments are a hook name, a step name. It
1389 should return an arrayref containing the code_ref to run, and the
1390 name of the method looked for. It uses ->can to find the appropriate
1393 my $code = $self->hook('finalize', 'main');
1394 ### will look first for $self->main_finalize;
1395 ### will then look for $self->finalize;
1397 This system is used to allow for multiple steps to be in the same
1398 file and still allow for moving some steps out to external sub classed
1399 packages (if desired).
1401 If the application has successfully morphed via the morph method and
1402 allow_morph then it is not necessary to add the step name to the
1403 beginning of the method name as the morphed packages method will
1404 override the base package (it is still OK to use the full method name
1405 "${step}_hookname").
1407 See the run_hook method and the morph method for more details.
1409 =item first_step (method)
1411 Returns the first step of the path. Note that first_step may not be the same
1412 thing as default_step if the path was overridden.
1414 =item forbidden_step (method)
1416 Defaults to "__forbidden". The name of a step to run should the current
1417 step name be invalid, or if a step found by the default path method
1418 is invalid. See the path method.
1422 Returns a hashref of the items passed to the CGI. Returns
1423 $self->{form} which defaults to CGI::Ex::get_form.
1425 =item form_name (hook)
1427 Return the name of the form to attach the js validation to. Used by
1430 =item get_pass_by_user (method)
1432 This method is passed a username and the authentication object. It
1433 should return the password for the given user. See the get_pass_by_user
1434 method of CGI::Ex::Auth for more information. Installed as a hook
1435 to the authentication object during the get_valid_auth method.
1437 =item get_valid_auth (method)
1439 If require_auth hook returns true on any given step then get_valid_auth will be called.
1441 It will call auth_args to get some default args to pass to
1442 CGI::Ex::Auth->new. It augments the args with sensible defaults that
1443 App already provides (such as form, cookies, and template facilities).
1444 It also installs hooks for the get_pass_by_user, cleanup_user, and verify_user
1445 hooks of CGI::Ex::Auth.
1447 It stores the $auth->last_auth_data in $self->auth_data for later use. For
1448 example, to get the authenticated user:
1450 sub require_auth { 1 }
1453 my ($self, $user) = @_;
1457 sub get_pass_by_user {
1458 my ($self, $user) = @_;
1459 my $pass = $self->some_method_to_get_the_pass($user);
1465 login_header => '<h1>My login header</h1>',
1466 login_footer => '[% TRY %][% INCLUDE login/login_footer.htm %][% CATCH %]<!-- [% error %] -->[% END %]',
1470 sub main_hash_swap {
1472 my $user = $self->auth_data->{'user'};
1473 return {user => $user};
1476 Successful authentication is cached for the duration of the
1477 nav_loop so multiple steps will run the full authentication routine
1480 Full customization of the login process and the login template can
1481 be done via the auth_args hash. See the auth_args method and
1482 CGI::Ex::Auth perldoc for more information.
1484 =item handle_error (method)
1486 If anything dies during execution, handle_error will be called with
1487 the error that had happened. Default action is to try running the
1488 step returned by the error_step method.
1490 =item hash_base (hook)
1492 A hash of base items to be merged with hash_form - such as pulldown
1493 menus, javascript validation, etc. It will now also be merged with
1494 hash_fill, so it can contain default fillins as well. It can be
1495 populated by passing a hash to ->add_to_base. By default a sub
1496 similar to the following is what is used for hash_common. Note the
1497 use of values that are code refs - so that the js_validation and
1498 form_name hooks are only called if requested:
1501 my ($self, $step) = @_;
1502 return $self->{hash_base} ||= {
1503 script_name => $ENV{SCRIPT_NAME},
1504 js_validation => sub { $self->run_hook('js_validation', $step) },
1505 form_name => sub { $self->run_hook('form_name', $step) },
1509 =item hash_common (hook)
1511 Almost identical in function and purpose to hash_base. It is
1512 intended that hash_base be used for common items used in various
1513 scripts inheriting from a common CGI::Ex::App type parent. Hash_common
1514 is more intended for step level populating of both swap and fill.
1516 =item hash_errors (hook)
1518 Called in preparation for print after failed prepare, info_complete,
1519 or finalize. Should contain a hash of any errors that occurred. Will
1520 be merged into hash_form before the pass to print. Each error that
1521 occurred will be passed to method format_error before being added to
1522 the hash. If an error has occurred, the default validate will
1523 automatically add {has_errors =>1}. To the error hash at the time of
1524 validation. has_errors will also be added during the merge in case the
1525 default validate was not used. Can be populated by passing a hash to
1526 ->add_to_errors or ->add_errors.
1528 =item hash_fill (hook)
1530 Called in preparation for print after failed prepare, info_complete,
1531 or finalize. Should contain a hash of any items needed to be filled
1532 into the html form during print. Items from hash_form, hash_base, and
1533 hash_common will be layered together. Can be populated by passing a
1534 hash to ->add_to_fill.
1536 By default - forms are sticky and data from previous requests will try
1537 and populate the form. You can use the fill_template hook to disable
1538 templating on a single page or on all pages.
1540 This method can be used to pre-populate the form as well (such as on an
1541 edit step). If a form fails validation, hash_fill will also be called
1542 and will only want the submitted form fields to be sticky. You can
1543 use the ready_validate hook to prevent pre-population in these cases as
1546 sub edit_hash_fill {
1549 return {} if $self->run_hook('ready_validate', $step);
1553 ### get previous values from the database
1558 =item hash_form (hook)
1560 Called in preparation for print after failed prepare, info_complete,
1561 or finalize. Defaults to ->form. Can be populated by passing a hash
1564 =item hash_swap (hook)
1566 Called in preparation for print after failed prepare, info_complete,
1567 or finalize. Should contain a hash of any items needed to be swapped
1568 into the html during print. Will be merged with hash_base,
1569 hash_common, hash_form, and hash_errors. Can be populated by passing
1570 a hash to ->add_to_swap.
1572 The hash will be passed as the second argument to swap_template.
1574 =item hash_validation (hook)
1576 Returns a hash of the validation information to check form against.
1577 By default, will look for a filename using the hook file_val and will
1578 pass it to CGI::Ex::Validate::get_validation. If no file_val is
1579 returned or if the get_validation fails, an empty hash will be returned.
1580 Validation is implemented by ->vob which loads a CGI::Ex::Validate object.
1582 =item history (method)
1584 Returns an arrayref which contains trace history of which hooks of
1585 which steps were ran. Useful for seeing what happened. In general -
1586 each line of the history will show the current step, the hook
1587 requested, and which hook was actually called.
1589 The dump_history method shows a short condensed version of this
1590 history which makes it easier to see what path was followed.
1592 In general, the arrayref is free for anything to push onto which will
1593 help in tracking other occurrences in the program as well.
1595 =item info_complete (hook)
1597 Calls the ready_validate hook to see if data is ready to validate. If
1598 so it calls the validate hook to validate the data. Should make
1599 sure the data is ready and valid. Will not be run unless
1600 prepare returns true (default).
1604 Called by the default new method. Allows for any object
1605 initilizations that may need to take place. Default action does
1608 =item init_from_conf (method)
1610 Called by the default new method. If load_conf is true, then the
1611 conf method will be called and the keys returned will be added to
1614 This method is called after the init method. If you need to further
1615 fix up values added during init_from_conf, you can use the pre_navigate
1618 =item insert_path (method)
1620 Arguments are the steps to insert. Can be called any time. Inserts
1621 the new steps at the current path location.
1623 =item is_authed (method)
1625 Returns true if the object has successful authentication data. It
1626 returns false if the object has not been authenticated.
1628 =item js_uri_path (method)
1630 Return the URI path where the CGI/Ex/yaml_load.js and
1631 CGI/Ex/validate.js files can be found. This will default to
1632 "$ENV{SCRIPT_NAME}/js" if the path method has not been overridden,
1633 otherwise it will default to "$ENV{SCRIPT_NAME}?step=js&js=" (the
1634 latter is more friendly with overridden paths). A default handler for
1635 the "js" step has been provided in "js_run_step" (this handler will
1636 nicely print out the javascript found in the js files which are
1637 included with this distribution. js_run_step will work properly with the
1638 default "path" handler.
1640 =item js_validation (hook)
1642 Requires JSON or YAML. Will return Javascript that is capable of
1643 validating the form. This is done using the capabilities of
1644 CGI::Ex::Validate. This will call the hook hash_validation which will
1645 then be encoded either json or into yaml and placed in a javascript
1646 string. It will also call the hook form_name to determine which html
1647 form to attach the validation to. The method js_uri_path is called to
1648 determine the path to the appropriate validate.js files. If the
1649 method ext_val is htm, then js_validation will return an empty string
1650 as it assumes the htm file will take care of the validation itself.
1651 In order to make use of js_validation, it must be added to the
1652 variables returned by either the hash_base, hash_common, hash_swap or
1653 hash_form hook (see examples of hash_base used in this doc).
1655 By default it will try and use JSON first and then fail to YAML and
1656 then will fail to returning an html comment that does nothing.
1660 This method should not normally be used but is fine to use it on a
1661 regular basis. It provides for moving to the next step at any point
1662 during the nav_loop. It effectively short circuits the remaining
1663 hooks for the current step. It does increment the recursion counter
1664 (which has a limit of ->recurse_limit - default 15). It is normally
1665 better to allow the other hooks in the loop to carry on their normal
1666 functions and avoid jumping. (Essentially, this hook behaves like a
1667 goto method to bypass everything else and continue at a different
1668 location in the path - there are times when it is necessary or useful
1671 Jump takes a single argument which is the location in the path to jump
1672 to. This argument may be either a step name, the special strings
1673 "FIRST, LAST, CURRENT, PREVIOUS, OR NEXT" or the number of steps to
1674 jump forward (or backward) in the path. The default value, 1,
1675 indicates that CGI::Ex::App should jump to the next step (the default
1676 action for jump). A value of 0 would repeat the current step (watch
1677 out for recursion). A value of -1 would jump to the previous step.
1678 The special value of "LAST" will jump to the last step. The special
1679 value of "FIRST" will jump back to the first step. In each of these
1680 cases, the path array returned by ->path is modified to allow for the
1681 jumping (the path is modified so that the path history is not destroyed
1682 - if we were on step 3 and jumped to one, that path would contain
1683 1, 2, 3, *1, 2, 3, 4, etc and we would be at the *).
1685 ### goto previous step
1686 $self->jump($self->previous_step);
1687 $self->jump('PREVIOUS');
1691 $self->jump($self->next_step);
1692 $self->jump('NEXT');
1696 ### goto current step (repeat)
1697 $self->jump($self->current_step);
1698 $self->jump('CURRENT');
1702 $self->jump($self->last_step);
1703 $self->jump('LAST');
1706 $self->jump($self->first_step);
1707 $self->jump('FIRST');
1709 =item last_step (method)
1711 Returns the last step of the path. Can be used to jump to the last step.
1713 =item load_conf (method)
1715 Defaults to ->{load_conf} which defaults to false. If true, will
1716 allow keys returned by the conf method to be added to $self during
1717 the init_from_conf method.
1719 Enabling this method allows for out-of-the-box file based configuration.
1721 =item morph (method)
1723 Allows for temporarily "becoming" another object type for the
1724 execution of the current step. This allows for separating some steps
1725 out into their own packages.
1727 Morph will only run if the method allow_morph returns true.
1728 Additionally if the allow_morph returns a hash ref, morph will only
1729 run if the step being morphed to is in the hash. Morph also passes
1730 the step name to allow_morph.
1732 The morph call occurs at the beginning of the step loop. A
1733 corresponding unmorph call occurs before the loop is exited. An
1734 object can morph several levels deep if allow_nested_morph returns
1735 true. For example, an object running as Foo::Bar that is looping on
1736 the step "my_step" that has allow_morph = 1, will do the following:
1738 Call the morph_package hook (which would default to returning
1739 Foo::Bar::MyStep in this case)
1741 Translate this to a package filename (Foo/Bar/MyStep.pm) and try
1742 and require it, if the file can be required, the object is blessed
1745 Call the fixup_after_morph method.
1747 Continue on with the run_step for the current step.
1749 At any exit point of the loop, the unmorph call is made which
1750 re-blesses the object into the original package.
1752 Samples of allowing morph:
1754 sub allow_morph { 1 }
1756 sub allow_morph { {edit => 1} }
1758 sub allow_morph { my ($self, $step) = @_; return $step eq 'edit' }
1760 It is possible to call morph earlier on in the program. An example of
1761 a useful early use of morph would be as in the following code:
1763 sub allow_morph { 1 }
1767 if ($ENV{'PATH_INFO'} && $ENV{'PATH_INFO'} =~ s|^/(\w+)||) {
1769 $self->morph($step);
1770 $ENV{'PATH_INFO'} = "/$step";
1771 $self->stash->{'base_morphed'} = 1;
1778 $self->unmorph if $self->stash->{'base_morphed'};
1781 If this code was in a module Base.pm and the cgi running was cgi/base
1786 and you created a sub module that inherited Base.pm called
1787 Base/Ball.pm -- you could then access it using cgi/base/ball. You
1788 would be able to pass it steps using either cgi/base/ball/step_name or
1789 cgi/base/ball?step=step_name - Or Base/Ball.pm could implement its
1790 own path. It should be noted that if you do an early morph, it is
1791 suggested to provide a call to unmorph. And if you want to let your
1792 early morphed object morph again - you will need to provide
1794 sub allow_nested_morph { 1 }
1796 With allow_nested_morph enabled you could create the file
1797 Base/Ball/StepName.pm which inherits Base/Ball.pm. The Base.pm, with
1798 the custom init and default path method, would automatically morph us
1799 first into a Base::Ball object (during init) and then into a
1800 Base::Ball::StepName object (during the navigation loop).
1802 Since it is complicated to explain - it may be a bit complicated to
1803 those who will try to follow your code later. CGI::Ex::App provides
1804 many ways to do things, but use the best one for your situation.
1806 =item morph_package (hook)
1808 Used by morph. Return the package name to morph into during a morph
1809 call. Defaults to using the current object type as a base. For
1810 example, if the current object running is a Foo::Bar object and the
1811 step running is my_step, then morph_package will return
1814 Because of the way that run_hook works, it is possible that several
1815 steps could be located in the same external file and overriding morph_package
1816 could allow for this to happen.
1818 See the morph method.
1820 =item name_module (hook)
1822 Return the name (relative path) that should be pre-pended to name_step
1823 during the default file_print and file_val lookups. Defaults to
1824 the value in $self->{name_module} which in turn defaults to the name
1825 of the current script.
1827 cgi-bin/my_app.pl => my_app
1828 cgi/my_app => my_app
1830 This method is provided so that each cgi or mod_perl application can
1831 have its own directory for storing html for its steps.
1833 See the file_print method for more information.
1835 See the section on FINDING TEMPLATES for further discussion.
1837 =item name_step (hook)
1839 Return the step (appended to name_module) that should used when
1840 looking up the file in file_print and file_val lookups. Defaults to
1843 See the section on FINDING TEMPLATES for further discussion.
1845 =item nav_loop (method)
1847 This is the main loop runner. It figures out the current path
1848 and runs all of the appropriate hooks for each step of the path. If
1849 nav_loop runs out of steps to run (which happens if no path is set, or if
1850 all other steps run successfully), it will insert the ->default_step into
1851 the path and run nav_loop again (recursively). This way a step is always
1852 assured to run. There is a method ->recurse_limit (default 15) that
1853 will catch logic errors (such as inadvertently running the same
1854 step over and over and over because there is either no hash_validation,
1855 or the data is valid but the set_ready_validate(0) method was not called).
1857 =item navigate (method)
1859 Takes a class name or a CGI::Ex::App object as arguments. If a class
1860 name is given it will call the "new" method to instantiate an object
1861 by that class (passing any extra arguments to the new method). All
1862 returns from navigate will return the object.
1864 The method navigate is essentially a safe wrapper around the ->nav_loop
1865 method. It will catch any dies and pass them to ->handle_error.
1867 This starts the process flow for the path and its steps.
1869 =item navigate_authenticated (method)
1871 Same as the method navigate but calls ->require_auth(1) before
1872 running. It will only work if the navigate_authenticated method
1873 has not been overwritten. See the require_auth method.
1875 =item new (class method)
1877 Object creator. Takes a hashref of arguments that will become the
1878 initial properties of the object. Calls the init method once the
1879 object has been blessed to allow for any other initilizations.
1881 my $app = MyApp->new({name_module => 'my_app'});
1883 =item next_step (hook and method)
1885 Returns the next step in the path. If there is no next step, it
1886 returns the default_step.
1888 It can be used as a method to return the next step in the path
1889 to pass to a method such as ->jump.
1891 It is also used as a hook by the refine_path hook. If there is no
1892 more steps, it will call the next_step hook to try and find a step to
1897 Return an arrayref (modifiable) of the steps in the path. For each
1898 step the run_step hook and all of its remaining hooks will be run.
1900 Hook methods are looked up and ran using the method "run_hook" which
1901 uses the method "find_hook" to lookup the hook. A history of ran
1902 hooks is stored in the array ref returned by $self->history.
1904 If path has not been defined, the method will look first in the form
1905 for a key by the name found in ->step_key. It will then look in
1906 $ENV{'PATH_INFO'}. It will use this step to create a path with that
1907 one step as its contents. If a step is passed in via either of these
1908 ways, the method will call valid_steps to make sure that the step
1909 is valid (by default valid_steps returns undef - which means that
1910 any step is valid). Any step beginning with _ can not be passed in
1911 and are intended for use on private paths. If a non-valid step is
1912 found, then path will be set to contain a single step of ->forbidden_step.
1914 For the best functionality, the arrayref returned should be the same
1915 reference returned for every call to path - this ensures that other
1916 methods can add to the path (and will most likely break if the
1917 arrayref is not the same).
1919 If navigation runs out of steps to run, the default step found in
1920 default_step will be run. This is what allows for us to default
1921 to the "main" step for many applications.
1923 =item path_info_map (hook)
1925 Used to map path_info parts to form variables. Similar to the
1926 path_info_map_base method. See the path_info_map_base method
1927 for a discussion of how to use this hook.
1929 =item path_info_map_base (method)
1931 Called during the default path method. It is used to custom map portions
1932 of $ENV{'PATH_INFO'} to form values. If should return an arrayref of
1933 arrayrefs where each child arrayref contains a regex qr with match parens
1934 as the first element of the array. Subsequent elements of the array are
1935 the key names to store the corresponding matched value from the regex under.
1936 The outer arrayref is iterated until it one of child arrayrefs matches
1937 against $ENV{'PATH_INFO'}. The matched values are only added to the form if
1938 there is not already a defined value for that key in the form.
1940 The default value returned by this method looks something like the following:
1942 sub path_info_map_base {
1943 return [[qr{^/(\w+)}, $self->step_key]];
1946 This example would map the following PATH_INFO string as follows:
1950 # $self->form->{'step'} now equals "my_step"
1952 The following is another example:
1954 sub path_info_map_base {
1956 [qr{^/([^/]+)/(\w+)}, 'username', $self->step_key],
1957 [qr{^/(\w+)}, $self->step_key],
1961 # the PATH_INFO /my_step
1963 # $self->form->{'step'} now equals "my_step"
1965 # but with the PATH_INFO /my_user/my_step
1966 # $self->form->{'step'} now equals "my_step"
1967 # and $self->form->{'username'} equals "my_user"
1969 In most cases there is not a need to override the path_info_map_base
1970 method, but rather override the path_info_map hook for a particular step.
1971 When the step is being run, just before the run_step hook is called, the
1972 path_info_map hook is called. The path_info_map hook is similar to
1973 the path_info_map_base method, but is used to allow step level manipulation
1974 of form based on elements in the $ENV{'PATH_INFO'}.
1976 sub my_step_path_info_map {
1977 return [[qr{^/my_step/(\w+)$}, 'username']];
1980 # the PATH_INFO /my_step/my_user
1982 # $self->form->{'step'} equal to "my_step" because of default path_info_map_base
1983 # and $self->form->{'username'} equals "my_user" because of my_step_path_info_map
1985 The section on mapping URIs to steps has additional examples.
1987 =item post_loop (method)
1989 Ran after all of the steps in the loop have been processed (if
1990 prepare, info_complete, and finalize were true for each of the steps).
1991 If it returns a true value the navigation loop will be aborted. If it
1992 does not return true, navigation continues by then inserting the step
1993 $self->default_step and running $self->nav_loop again (recurses) to
1994 fall back to the default step.
1996 =item post_navigate (method)
1998 Called from within navigate. Called after the nav_loop has finished
1999 running but within the eval block to catch errors. Will only run if
2000 there were no errors which died during the nav_loop process.
2002 It can be disabled from running by setting the _no_post_navigate
2005 If per-step authentication is enabled and authentication fails,
2006 the post_navigate method will still be called (the post_navigate
2007 method can check the ->is_authed method to change behavior). If
2008 application level authentication is enabled and authentication
2009 fails, none of the pre_navigate, nav_loop, or post_navigate methods
2012 =item post_print (hook)
2014 A hook which occurs after the printing has taken place. Is only run
2015 if the information was not complete. Useful for cases such as
2016 printing rows of a database query after displaying a query form.
2018 =item post_step (hook)
2020 Ran at the end of the step's loop if prepare, info_complete, and
2021 finalize all returned true. Allows for cleanup. If a true value is
2022 returned, execution of navigate is returned and no more steps are
2025 =item pre_loop (method)
2027 Called right before the navigation loop is started (at the beginning
2028 of nav_loop). At this point the path is set (but could be modified).
2029 The only argument is a reference to the path array. If it returns a
2030 true value - the navigation routine is aborted.
2032 =item pre_navigate (method)
2034 Called at the very beginning of the navigate method, but within the
2035 eval block to catch errors. Called before the nav_loop method is
2036 started. If a true value is returned then navigation is skipped (the
2037 nav_loop is never started).
2039 =item pre_step (hook)
2041 Ran at the beginning of the loop before prepare, info_compelete, and
2042 finalize are called. If it returns true, execution of nav_loop is
2043 returned and no more steps are processed..
2045 =item prepare (hook)
2047 Defaults to true. A hook before checking if the info_complete is true.
2048 Intended to be used to cleanup the form data.
2050 =item prepared_print (hook)
2052 Called when any of prepare, info_complete, or finalize fail. Prepares
2053 a form hash and a fill hash to pass to print. The form hash is primarily
2054 intended for use by the templating system. The fill hash is intended
2055 to be used to fill in any html forms.
2057 =item previous_step (method)
2059 List the step previous to this one. Will return '' if there is no previous step.
2063 Take the information generated by prepared_print, format it using
2064 swap_template, fill it using fill_template and print it out using
2065 print_out. Default incarnation uses CGI::Ex::Template (a subclass of
2066 Template::Alloy) which is compatible with Template::Toolkit to do the
2067 swapping. Arguments are: step name (used to call the file_print
2068 hook), swap hashref (passed to call swap_template), and fill hashref
2069 (passed to fill_template).
2071 During the print call, the file_print hook is called which should
2072 return a filename or a scalar reference to the template content is
2074 =item print_out (hook)
2076 Called with the finished document. Should print out the appropriate headers.
2077 The default method calls $self->cgix->print_content_type and then
2080 The print_content_type is passed $self->mimetype (which defaults to
2081 $self->{'mimetype'} which defaults to 'text/html') and $self->charset
2082 (which defaults to $self->{'charset'} which defaults to '').
2084 =item ready_validate (hook)
2086 Should return true if enough information is present to run validate.
2087 Default is to look if $ENV{'REQUEST_METHOD'} is 'POST'. A common
2088 usage is to pass a common flag in the form such as 'processing' => 1
2089 and check for its presence - such as the following:
2091 sub ready_validate { shift->form->{'processing'} }
2093 Changing the behavior of ready_validate can help in making wizard type
2096 =item refine_path (hook)
2098 Called at the end of nav_loop. Passed a single value indicating
2099 if there are currently more steps in the path.
2101 The default implementation returns if there are still more steps
2102 in the path. Otherwise, it calls the next_step hook and appends
2103 it to the path with the append_path method, and then calls
2104 the set_ready_validate hook and passes it 0.
2106 This allows you to simply put
2108 sub edit_next_step { '_edit_success' }
2110 In your code and it will automatically do the right thing and
2111 go to the _edit_success step.
2113 =item recurse_limit (method)
2115 Default 15. Maximum number of times to allow nav_loop to call itself.
2116 The recurse level will increase every time that ->jump is called, or if
2117 the end of the nav_loop is reached and the process tries to add the
2118 default_step and run it again.
2120 If ->jump is used often - the recurse_limit will be reached more
2121 quickly. It is safe to raise this as high as is necessary - so long
2122 as it is intentional.
2124 Often the limit is reached if a step did not have a validation hash,
2125 or if the set_ready_validate(0) method was not called once the data
2126 had been successfully validated and acted upon.
2128 =item replace_path (method)
2130 Arguments are the steps used to replace. Can be called any time.
2131 Replaces the remaining steps (if any) of the current path.
2133 =item require_auth (hook)
2135 Defaults to self->{require_auth} which defaults to undef.
2136 If called as a method and passed a single value of 1, 0, or undef it will
2137 set the value of $self->{require_auth} to that value. If set to a true
2138 value then any subsequent step will require authentication (unless its
2139 hook has been overwritten).
2141 Any of the following ways can be used to require authentication on
2148 sub require_auth { 1 }
2152 __PACKAGE__->navigate_authenticated; # instead of __PACKAGE__->navigate;
2156 __PACKAGE__->new({require_auth => 1}->navigate;
2160 sub init { shift->require_auth(1) }
2164 Because it is called as a hook, the current step is passed as the
2165 first argument. If the hook returns false, no authentication will be
2166 required on this step. If the hook returns a true, non-hashref value,
2167 authentication will be required via the get_valid_auth method. If the
2168 method returns a hashref of stepnames to require authentication on,
2169 the step will require authentication via the get_valid_auth method if
2170 the current step is in the hashref. If authentication is required and
2171 succeeds, the step will proceed. If authentication is required and
2172 fails at the step level the current step will be aborted,
2173 authentication will be asked for (the post_navigate method will still
2176 For example you could add authentication to the add, edit, and delete
2177 steps in any of the following ways:
2183 sub require_auth { {add => 1, edit => 1, delete => 1} }
2187 sub add_require_auth { 1 }
2188 sub edit_require_auth { 1 }
2189 sub delete_require_auth { 1 }
2194 my ($self, $step) = @_;
2195 return 1 if $step && $step =~ /^(add|edit|delete)$/;
2201 If however you wanted to require authentication on all but one or two methods
2202 (such as requiring authentication on all but a forgot_password step) you could do
2203 either of the following:
2210 my ($self, $step) = @_;
2211 return 0 if $step && $step eq 'forgot_password';
2212 return 1; # require auth on all other steps
2217 sub require_auth { 1 } # turn it on for all steps
2219 sub forgot_password_require_auth { 0 } # turn it off
2223 See the get_valid_auth method for what occurs should authentication be required.
2225 There is one key difference from the 2.14 version of App. In 2.14 and
2226 previous versions, the pre_navigate and post_navigate methods would
2227 not be called if require_auth returned a true non-hashref value. In
2228 version 2.15 and later, the 2.15 pre_navigate and post_navigate
2229 methods are always called - even if authentication fails. Also in 2.15
2230 and later, the method is called as a hook meaning the step is passed in.
2232 =item run_hook (method)
2234 Arguments are a hook name and the step to find the hook for. Calls
2235 the find_hook method to get a code ref which it then calls and returns
2236 the result passing any extra arguments to run_hook as arguments to the
2239 Each call to run_hook is logged in the arrayref returned by the
2240 history method. This information is summarized in the dump_history
2241 method and is useful for tracing the flow of the program.
2243 The run_hook method is part of the core of CGI::Ex::App. It allows
2244 for an intermediate layer in normal method calls. Because of
2245 run_hook, it is possible to logically override methods on a step by
2246 step basis, or override a method for all of the steps, or even to
2247 break code out into separate modules.
2249 =item run_step (hook)
2251 Runs all of the hooks specific to each step, beginning with pre_step
2252 and ending with post_step (for a full listing of steps, see the
2253 section on process flow). Called after ->morph($step) has been run.
2254 If this hook returns true, the nav_loop is exited (meaning the
2255 run_step hook displayed a printed page). If it returns false, the
2256 nav_loop continues on to run the next step.
2258 This hook performs the same base functionality as a method defined in
2259 CGI::Applications ->run_modes. The default run_step method provides
2260 much more granular control over the flow of the CGI.
2262 =item set_path (method)
2264 Arguments are the steps to set. Should be called before navigation
2265 begins. This will set the path arrayref to the passed steps.
2267 This method is not normally used.
2269 =item set_ready_validate (hook and method)
2271 Sets that the validation is ready (or not) to validate. Should set the value
2272 checked by the hook ready_validate. The following would complement the
2273 processing flag above:
2275 sub set_ready_validate {
2277 my ($step, $is_ready) = (@_ == 2) ? @_ : (undef, shift);
2279 $self->form->{'processing'} = 1;
2281 delete $self->form->{'processing'};
2286 Note that for this example the form key "processing" was deleted. This
2287 is so that the call to fill in any html forms won't swap in a value of
2288 zero for form elements named "processing."
2290 Also note that this method may be called as a hook as in
2292 $self->run_hook('set_ready_validate', $step, 0)
2294 $self->set_ready_validate($step, 0);
2296 Or it can take a single argument and should set the ready status
2297 regardless of the step as in:
2299 $self->set_ready_validate(0);
2303 Ran at the beginning of the loop before prepare, info_complete, and
2304 finalize are called. If it returns true, nav_loop moves on to the
2305 next step (the current step is skipped).
2307 =item stash (method)
2309 Returns a hashref that can store arbitrary user space data without
2310 worrying about overwriting the internals of the application.
2312 =item step_key (method)
2314 Should return the keyname that will be used by the default "path"
2315 method to look for in the form. Default value is 'step'.
2317 =item swap_template (hook)
2319 Takes the template and hash of variables prepared in print, and
2320 processes them through the current template engine (default engine is
2321 CGI::Ex::Template a subclass of Template::Alloy).
2323 Arguments are the template and the swap hashref. The template can be
2324 either a scalar reference to the actual content, or the filename of
2325 the content. If the filename is specified - it should be relative to
2326 template_path (which will be used to initialize INCLUDE_PATH by
2329 The default method will create a template object by calling the
2330 template_args hook and passing the returned hashref to the
2331 template_obj method. The default template_obj method returns a
2332 CGI::Ex::Template object, but could easily be swapped to use a
2333 Template::Toolkit based object. If a non-Template::Toolkit compatible
2334 object is to be used, then the swap_template hook can be overridden to
2335 use another templating engine.
2337 For example to use the HTML::Template engine you could override the swap_template
2343 my ($self, $step, $file, $swap) = @_;
2345 my $type = UNIVERSAL::isa($file, 'SCALAR') ? 'scalarref'
2346 : UNIVERSAL::isa($file, 'ARRAY') ? 'arrayref'
2347 : ref($file) ? 'filehandle'
2350 my $t = HTML::Template->new(source => $file,
2352 path => $self->template_path,
2353 die_on_bad_params => 0,
2361 As of version 2.13 of CGI::Ex::Template you could also simply do the
2362 following to parse the templates using HTML::Template::Expr syntax.
2365 return {SYNTAX => 'hte'};
2368 For a listing of the available syntaxes, see the current L<Template::Alloy> documentation.
2370 =item template_args (hook)
2372 Returns a hashref of args that will be passed to the "new" method of CGI::Ex::Template.
2373 The method is normally called from the swap_template hook. The swap_template hook
2374 will add a value for INCLUDE_PATH which is set equal to template_path, if the INCLUDE_PATH
2375 value is not already set.
2377 The returned hashref can contain any arguments that CGI::Ex::Template (a subclass of Template::Alloy)
2383 WRAPPER => 'wrappers/main_wrapper.html',
2387 See the L<Template::Alloy> documentation for a listing of all possible configuration arguments.
2389 =item template_obj (method)
2391 Called from swap_template. It is passed the result of template_args
2392 that have had a default INCLUDE_PATH added via template_path. The default
2393 implementation uses CGI::Ex::Template (a subclass of Template::Alloy)
2394 but can easily be changed to use Template::Toolkit by using code
2395 similar to the following:
2400 my ($self, $args) = @_;
2401 return Template->new($args);
2404 =item template_path (method)
2406 Defaults to $self->{'template_path'} which defaults to base_dir_abs. Used by
2407 the template_obj method.
2409 =item unmorph (method)
2411 Allows for returning an object back to its previous blessed state if
2412 the "morph" method was successful in morphing the App object. This
2413 only happens if the object was previously morphed into another object
2414 type. Before the object is re-blessed the method fixup_before_unmorph
2417 See allow_morph and morph.
2419 =item valid_steps (method)
2421 Called by the default path method. Should return a hashref of path
2422 steps that are allowed. If the current step is not found in the hash
2423 (or is not the default_step or js_step) the path method will return a
2424 single step of ->forbidden_step and run its hooks. If no hash or undef is
2425 returned, all paths are allowed (default). A key "forbidden_step"
2426 containing the step that was not valid will be placed in the stash.
2427 Often the valid_steps method does not need to be defined as arbitrary
2428 method calls are not possible with CGI::Ex::App.
2430 Any steps that begin with _ are also "not" valid for passing in via the form
2431 or path info. See the path method.
2433 Also, the pre_step, skip, prepare, and info_complete hooks allow for validating
2434 the data before running finalize.
2436 =item validate (hook)
2438 Passed the form from $self->form. Runs validation on the information
2439 contained in the passed form. Uses CGI::Ex::Validate for the default
2440 validation. Calls the hook hash_validation to load validation hashref
2441 (an empty hash means to pass validation). Should return true if the
2442 form passed validation and false otherwise. Errors are stored as a
2443 hash in $self->{hash_errors} via method add_errors and can be checked
2444 for at a later time with method has_errors (if the default validate
2447 There are many ways and types to validate the data. Please see the
2448 L<CGI::Ex::Validate> module.
2450 Upon success, it will look through all of the items which were
2451 validated, if any of them contain the keys append_path, insert_path,
2452 or replace_path, that method will be called with the value as
2453 arguments. This allows for the validation to apply redirection to the
2454 path. A validation item of:
2456 {field => 'foo', required => 1, append_path => ['bar', 'baz']}
2458 would append 'bar' and 'baz' to the path should all validation succeed.
2460 =item verify_user (method)
2462 Installed as a hook to CGI::Ex::App during get_valid_auth. Should return
2463 true if the user is ok. Default is to always return true. This can be
2464 used to abort early before the get_pass_by_user hook is called.
2467 my ($self, $user) = @_;
2468 return 0 if $user eq 'paul'; # don't let paul in
2469 return 1; # let anybody else in
2474 =head1 HOW DO I SET COOKIES, REDIRECT, ETC
2476 Often in your program you will want to set cookies or bounce to a differnt URL.
2477 This can be done using either the builtin CGI::Ex object or the built in
2478 CGI object. It is suggested that you only use the CGI::Ex methods as it will
2479 automatically send headers and method calls under cgi, mod_perl1, or mod_perl2.
2480 The following shows how to do basic items using the CGI::Ex object returned by
2485 =item printing content-type headers
2487 ### CGI::Ex::App prints headers for you,
2488 ### but if you are printing custom types, you can send your own
2489 $self->cgix->print_content_type;
2491 # $self->cgix->print_content_type('text/html');
2493 =item setting a cookie
2495 $self->cgix->set_cookie({
2497 -value => 'Some Value',
2502 =item redirecting to another URL
2504 $self->cgix->location_bounce("http://somewhereelse.com");
2505 $self->exit_nav_loop; # normally should do this to long jump out of navigation
2507 =item making a QUERY_STRING
2509 my $data = {foo => "bar", one => "two or three"};
2510 my $query = $self->cgix->make_form($data);
2511 # $query now equals "foo=bar&one=two%20or%20three"
2513 =item getting form parameters
2515 my $form = $self->form;
2517 In this example $form would now contain a hashref of all POST and GET parameters
2518 passed to the server. The form method calls $self->cgix->get_form
2519 which in turn uses CGI->param to parse values. Fields with multiple passed
2520 values will be in the form of an arrayref.
2522 =item getting cookies
2524 my $cookies = $self->cookies;
2526 In this example $cookies would be a hashref of all passed in cookies. The
2527 cookies method calls $self->cgix->get_cookies which in turn uses CGI->cookie
2532 See the CGI::Ex and CGI documentation for more information.
2534 =head1 COMPARISON TO OTHER APPLICATION MODULES
2536 The concepts used in CGI::Ex::App are not novel or unique. However, they
2537 are all commonly used and very useful. All application builders were
2538 built because somebody observed that there are common design patterns
2539 in CGI building. CGI::Ex::App differs in that it has found more common design
2540 patterns of CGI's than other application builders and tries to get in the way
2543 CGI::Ex::App is intended to be sub classed, and sub sub classed, and each step
2544 can choose to be sub classed or not. CGI::Ex::App tries to remain simple
2545 while still providing "more than one way to do it." It also tries to avoid
2546 making any sub classes have to call ->SUPER:: (although that is fine too).
2548 And if what you are doing on a particular is far too complicated or custom for
2549 what CGI::Ex::App provides, CGI::Ex::App makes it trivial to override all behavior.
2551 There are certainly other modules for building CGI applications. The
2552 following is a short list of other modules and how CGI::Ex::App is
2557 =item C<CGI::Application>
2559 Seemingly the most well know of application builders.
2560 CGI::Ex::App is different in that it:
2562 * Uses Template::Toolkit compatible CGI::Ex::Template (a
2563 subclass of Template::Alloy) by default.
2564 CGI::Ex::App can easily use another toolkit by simply
2565 overriding the ->swap_template method.
2566 CGI::Application uses HTML::Template.
2567 * Offers integrated data validation.
2568 CGI::Application has had custom plugins created that
2569 add some of this functionality. CGI::Ex::App has the benefit
2570 that validation is automatically available in javascript as well.
2571 * Allows the user to print at any time (so long as proper headers
2572 are sent. CGI::Application requires data to be pipelined.
2573 * Offers hooks into the various phases of each step ("mode" in
2574 CGI::Application lingo). CGI::Application provides only ->runmode
2575 which is only a dispatch.
2576 * Support for easily jumping around in navigation steps.
2577 * Support for storing some steps in another package.
2578 * Integrated authentication
2579 * Integrated form filling
2580 * Integrated PATH_INFO mapping
2582 CGI::Ex::App and CGI::Application are similar in that they take care
2583 of handling headers and they allow for calling other "runmodes" from
2584 within any given runmode. CGI::Ex::App's ->run_step is essentially
2585 equivalent to a method call defined in CGI::Application's ->run_modes.
2586 The ->run method of CGI::Application starts the application in the same
2587 manner as CGI::Ex::App's ->navigate call. Many of the hooks around
2588 CGI::Ex::App's ->run_step call are similar in nature to those provided by
2591 =item C<CGI::Prototype>
2593 There are actually many similarities. One of the nicest things about
2594 CGI::Prototype is that it is extremely short (very very short). The
2595 ->activate starts the application in the same manner as CGI::Ex::App's
2596 ->navigate call. Both use Template::Toolkit as the default template
2597 system (CGI::Ex::App uses CGI::Ex::Template which is TT compatible).
2598 CGI::Ex::App is differrent in that it:
2600 * Offers more hooks into the various phases of each step.
2601 * Support for easily jumping around in navigation steps.
2602 * Support for storing only some steps in another package.
2603 * Integrated data validation
2604 * Integrated authentication
2605 * Integrated form filling
2606 * Integrated PATH_INFO mapping
2611 =head1 SIMPLE EXTENDED EXAMPLE
2613 The following example shows the creation of a basic recipe
2614 database. It requires the use of DBD::SQLite, but that is all.
2615 Once you have configured the db_file and template_path methods
2616 of the "recipe" file, you will have a working script that
2617 does CRUD for the recipe table. The observant reader may ask - why
2618 not use Catalyst or Ruby on Rails? The observant programmer will
2619 reply that making a framework do something simple is easy, but making
2620 it do something complex is complex and any framework that tries to
2621 do the those complex things for you is too complex. CGI::Ex::App
2622 lets you write the complex logic but gives you the ability to
2623 not worry about the boring details such as template engines,
2624 or sticky forms, or cgi parameters, or data validation. Once
2625 you are setup and are running, you are only left with providing
2626 the core logic of the application.
2628 ### File: /var/www/cgi-bin/recipe (depending upon Apache configuration)
2629 ### --------------------------------------------
2632 use lib qw(/var/www/lib);
2637 ### File: /var/www/lib/Recipe.pm
2638 ### --------------------------------------------
2642 use base qw(CGI::Ex::App);
2643 use CGI::Ex::Dump qw(debug);
2648 ###------------------------------------------###
2651 # show what happened
2652 debug shift->dump_history;
2655 sub template_path { '/var/www/templates' }
2657 sub base_dir_rel { 'content' }
2659 sub db_file { '/var/www/recipe.sqlite' }
2663 if (! $self->{'dbh'}) {
2664 my $file = $self->db_file;
2665 my $exists = -e $file;
2666 $self->{'dbh'} = DBI->connect("dbi:SQLite:dbname=$file", '', '',
2668 $self->create_tables if ! $exists;
2670 return $self->{'dbh'};
2676 $self->dbh->do("CREATE TABLE recipe (
2677 id INTEGER PRIMARY KEY AUTOINCREMENT,
2678 title VARCHAR(50) NOT NULL,
2679 ingredients VARCHAR(255) NOT NULL,
2680 directions VARCHAR(255) NOT NULL,
2681 date_added VARCHAR(20) NOT NULL
2685 ###----------------------------------------------------------------###
2687 sub main_info_complete { 0 }
2689 sub main_hash_swap {
2692 my $s = "SELECT id, title, date_added
2694 ORDER BY date_added";
2695 my $data = $self->dbh->selectall_arrayref($s);
2696 my @data = map {my %h; @h{qw(id title date_added)} = @$_; \%h} @$data;
2703 ###----------------------------------------------------------------###
2705 sub add_name_step { 'edit' }
2707 sub add_hash_validation {
2709 'group order' => [qw(title ingredients directions)],
2727 my $form = $self->form;
2729 my $s = "SELECT COUNT(*) FROM recipe WHERE title = ?";
2730 my ($count) = $self->dbh->selectrow_array($s, {}, $form->{'title'});
2732 $self->add_errors(title => 'A recipe by this title already exists');
2736 $s = "INSERT INTO recipe (title, ingredients, directions, date_added)
2737 VALUES (?, ?, ?, ?)";
2738 $self->dbh->do($s, {}, $form->{'title'},
2739 $form->{'ingredients'},
2740 $form->{'directions'},
2743 $self->add_to_form(success => "Recipe added to the database");
2748 ###----------------------------------------------------------------###
2750 sub edit_skip { shift->form->{'id'} ? 0 : 1 }
2752 sub edit_hash_common {
2754 return {} if $self->ready_validate;
2756 my $sth = $self->dbh->prepare("SELECT * FROM recipe WHERE id = ?");
2757 $sth->execute($self->form->{'id'});
2758 my $hash = $sth->fetchrow_hashref;
2763 sub edit_hash_validation { shift->add_hash_validation(@_) }
2767 my $form = $self->form;
2769 my $s = "SELECT COUNT(*) FROM recipe WHERE title = ? AND id != ?";
2770 my ($count) = $self->dbh->selectrow_array($s, {}, $form->{'title'}, $form->{'id'});
2772 $self->add_errors(title => 'A recipe by this title already exists');
2776 $s = "UPDATE recipe SET title = ?, ingredients = ?, directions = ? WHERE id = ?";
2777 $self->dbh->do($s, {}, $form->{'title'},
2778 $form->{'ingredients'},
2779 $form->{'directions'},
2782 $self->add_to_form(success => "Recipe updated in the database");
2787 ###----------------------------------------------------------------###
2789 sub view_skip { shift->edit_skip(@_) }
2791 sub view_hash_common { shift->edit_hash_common(@_) }
2793 ###----------------------------------------------------------------###
2795 sub delete_skip { shift->edit_skip(@_) }
2797 sub delete_info_complete { 1 }
2799 sub delete_finalize {
2801 $self->dbh->do("DELETE FROM recipe WHERE id = ?", {}, $self->form->{'id'});
2803 $self->add_to_form(success => "Recipe deleted from the database");
2813 File: /var/www/templates/content/recipe/main.html
2814 ### --------------------------------------------
2817 <title>Recipe DB</title>
2821 [% IF success %]<span style="color:darkgreen"><h2>[% success %]</h2></span>[% END %]
2823 <table style="border:1px solid blue">
2824 <tr><th>#</th><th>Title</th><th>Date Added</th></tr>
2826 [% FOR row IN recipies %]
2828 <td>[% loop.count %].</td>
2829 <td><a href="[% script_name %]/view?id=[% row.id %]">[% row.title %]</a>
2830 (<a href="[% script_name %]/edit?id=[% row.id %]">Edit</a>)
2832 <td>[% row.date_added %]</td>
2836 <tr><td colspan=2 align=right><a href="[% script_name %]/add">Add new recipe</a></td></tr>
2842 File: /var/www/templates/content/recipe/edit.html
2843 ### --------------------------------------------
2846 <title>[% step == 'add' ? "Add" : "Edit" %] Recipe</title>
2848 <h1>[% step == 'add' ? "Add" : "Edit" %] Recipe</h1>
2850 <form method=post name=[% form_name %]>
2851 <input type=hidden name=step>
2855 [% IF step != 'add' ~%]
2857 <td><b>Id:</b></td><td>[% id %]</td></tr>
2858 <input type=hidden name=id>
2861 <td><b>Date Added:</b></td><td>[% date_added %]</td></tr>
2866 <td valign=top><b>Title:</b></td>
2867 <td><input type=text name=title>
2868 <span style='color:red' id=title_error>[% title_error %]</span></td>
2871 <td valign=top><b>Ingredients:</b></td>
2872 <td><textarea name=ingredients rows=10 cols=40 wrap=physical></textarea>
2873 <span style='color:red' id=ingredients_error>[% ingredients_error %]</span></td>
2876 <td valign=top><b>Directions:</b></td>
2877 <td><textarea name=directions rows=10 cols=40 wrap=virtual></textarea>
2878 <span style='color:red' id=directions_error>[% directions_error %]</span></td>
2881 <td colspan=2 align=right>
2882 <input type=submit value="[% step == 'add' ? 'Add' : 'Update' %]"></td>
2887 (<a href="[% script_name %]">Main Menu</a>)
2888 [% IF step != 'add' ~%]
2889 (<a href="[% script_name %]/delete?id=[% id %]">Delete this recipe</a>)
2897 File: /var/www/templates/content/recipe/view.html
2898 ### --------------------------------------------
2901 <title>[% title %] - Recipe DB</title>
2903 <h1>[% title %]</h1>
2904 <h3>Date Added: [% date_added %]</h3>
2906 <h2>Ingredients</h2>
2913 (<a href="[% script_name %]">Main Menu</a>)
2914 (<a href="[% script_name %]/edit?id=[% id %]">Edit this recipe</a>)
2918 ### --------------------------------------------
2922 The dbh method returns an SQLite dbh handle and auto creates the
2923 schema. You will normally want to use MySQL or Oracle, or Postgres
2924 and you will want your schema to NOT be auto-created.
2926 This sample uses hand rolled SQL. Class::DBI or a similar module
2927 might make this example shorter. However, more complex cases that
2928 need to involve two or three or four tables would probably be better
2929 off using the hand crafted SQL.
2931 This sample uses SQL. You could write the application to use whatever
2932 storage you want - or even to do nothing with the submitted data.
2934 We had to write our own HTML (Catalyst and Ruby on Rails do this for
2935 you). For most development work - the HTML should be in a static
2936 location so that it can be worked on by designers. It is nice that
2937 the other frameworks give you stub html - but that is all it is. It
2938 is worth about as much as copying and pasting the above examples. All
2939 worthwhile HTML will go through a non-automated design/finalization
2942 The add step used the same template as the edit step. We did
2943 this using the add_name_step hook which returned "edit". The template
2944 contains IF conditions to show different information if we were in
2945 add mode or edit mode.
2947 We reused code, validation, and templates. Code and data reuse is a
2950 The edit_hash_common returns an empty hashref if the form was ready to
2951 validate. When hash_common is called and the form is ready to
2952 validate, that means the form failed validation and is now printing
2953 out the page. To let us fall back and use the "sticky" form fields
2954 that were just submitted, we need to not provide values in the
2957 We use hash_common. Values from hash_common are used for both
2958 template swapping and filling. We could have used hash_swap and
2959 hash_fill independently.
2961 The hook main_info_complete is hard coded to 0. This basically says
2962 that we will never try and validate or finalize the main step - which
2963 is most often the case.
2965 =head1 SEPARATING STEPS INTO SEPARATE FILES
2967 It may be useful sometimes to separate some or all of the steps of an
2968 application into separate files. This is the way that CGI::Prototype
2969 works. This is useful in cases were some steps and their hooks are
2970 overly large - or are seldom used.
2972 The following modifications can be made to the previous "recipe db"
2973 example that would move the "delete" step into its own file. Similar
2974 actions can be taken to break other steps into their own file as well.
2977 ### File: /var/www/lib/Recipe.pm
2978 ### Same as before but add the following line:
2979 ### --------------------------------------------
2981 sub allow_morph { 1 }
2984 ### File: /var/www/lib/Recipe/Delete.pm
2985 ### Remove the delete_* subs from lib/Recipe.pm
2986 ### --------------------------------------------
2987 package Recipe::Delete;
2990 use base qw(Recipe);
2992 sub skip { shift->edit_skip(@_) }
2994 sub info_complete { 1 }
2998 $self->dbh->do("DELETE FROM recipe WHERE id = ?", {}, $self->form->{'id'});
3000 $self->add_to_form(success => "Recipe deleted from the database");
3007 The hooks that are called (skip, info_complete, and finalize) do not
3008 have to be prefixed with the step name because they are now in their
3009 own individual package space. However, they could still be named
3010 delete_skip, delete_info_complete, and delete_finalize and the
3011 run_hook method will find them (this would allow several steps with
3012 the same "morph_package" to still be stored in the same external
3015 The method allow_morph is passed the step that we are attempting to
3016 morph to. If allow_morph returns true every time, then it will try
3017 and require the extra packages every time that step is ran. You could
3018 limit the morphing process to run only on certain steps by using code
3019 similar to the following:
3021 sub allow_morph { return {delete => 1} }
3026 my ($self, $step) = @_;
3027 return ($step eq 'delete') ? 1 : 0;
3030 The CGI::Ex::App temporarily blesses the object into the
3031 "morph_package" for the duration of the step and re-blesses it into the
3032 original package upon exit. See the morph method and allow_morph for more
3035 =head1 RUNNING UNDER MOD_PERL
3037 The previous samples are essentially suitable for running under flat CGI,
3038 Fast CGI, or mod_perl Registry or mod_perl PerlRun type environments. It
3039 is very easy to move the previous example to be a true mod_perl handler.
3041 To convert the previous recipe example, simply add the following:
3043 ### File: /var/www/lib/Recipe.pm
3044 ### Same as before but add the following lines:
3045 ### --------------------------------------------
3053 ### File: apache2.conf - or whatever your apache conf file is.
3054 ### --------------------------------------------
3056 SetHandler perl-script
3062 Both the /cgi-bin/recipe version and the /recipe version can co-exist.
3063 One of them will be a normal cgi and the other will correctly use
3064 mod_perl hooks for headers.
3066 Setting the location to /recipe means that the $ENV{SCRIPT_NAME} will
3067 also be set to /recipe. This means that name_module method will
3068 resolve to "recipe". If a different URI location is desired such as
3069 "/my_cool_recipe" but the program is to use the same template content
3070 (in the /var/www/templates/content/recipe directory), then we would
3071 need to explicitly set the "name_module" parameter. It could be done
3072 in either of the following ways:
3074 ### File: /var/www/lib/Recipe.pm
3075 ### Same as before but add the following line:
3076 ### --------------------------------------------
3078 sub name_module { 'recipe' }
3084 $self->{'name_module'} = 'recipe';
3087 In most use cases it isn't necessary to set name_module, but it also
3088 doesn't hurt and in all cases it is more descriptive to anybody who is
3089 going to maintain the code later.
3091 =head1 ADDING AUTHENTICATION TO THE ENTIRE APPLICATION
3093 Having authentication is sometimes a good thing. To force
3094 the entire application to be authenticated (require a valid username
3095 and password before doing anything) you could do the following.
3097 ### File: /var/www/lib/Recipe.pm
3098 ### Same as before but add
3099 ### --------------------------------------------
3101 sub get_pass_by_user {
3104 my $pass = $self->lookup_and_cache_the_pass($user);
3109 ### File: /var/www/cgi-bin/recipe (depending upon Apache configuration)
3110 ### Change the line with ->navigate; to
3111 ### --------------------------------------------
3113 Recipe->navigate_authenticated;
3117 ### File: /var/www/lib/Recipe.pm
3118 ### Same as before but add
3119 ### --------------------------------------------
3121 sub require_auth { 1 }
3125 ### File: /var/www/lib/Recipe.pm
3126 ### Same as before but add
3127 ### --------------------------------------------
3129 sub init { shift->require_auth(1) }
3131 See the require_auth, get_valid_auth, and auth_args methods for more information.
3132 Also see the L<CGI::Ex::Auth> perldoc.
3134 =head1 ADDING AUTHENTICATION TO INDIVIDUAL STEPS
3136 Sometimes you may only want to have certain steps require
3137 authentication. For example, in the previous recipe example we
3138 might want to let the main and view steps be accessible to anybody,
3139 but require authentication for the add, edit, and delete steps.
3141 To do this, we would do the following to the original example (the
3142 navigation must start with ->navigate. Starting with ->navigate_authenticated
3143 will cause all steps to require validation):
3145 ### File: /var/www/lib/Recipe.pm
3146 ### Same as before but add
3147 ### --------------------------------------------
3149 sub get_pass_by_user {
3152 my $pass = $self->lookup_and_cache_the_pass($user);
3156 sub require_auth { {add => 1, edit => 1, delete => 1} }
3158 We could also enable authentication by using individual hooks as in:
3160 sub add_require_auth { 1 }
3161 sub edit_require_auth { 1 }
3162 sub delete_require_auth { 1 }
3164 Or we could require authentication on everything - but let a few steps in:
3166 sub require_auth { 1 } # turn authentication on for all
3167 sub main_require_auth { 0 } # turn it off for main and view
3168 sub view_require_auth { 0 }
3170 That's it. The add, edit, and delete steps will now require authentication.
3171 See the require_auth, get_valid_auth, and auth_args methods for more information.
3172 Also see the L<CGI::Ex::Auth> perldoc.
3176 The following corporation and individuals contributed in some part to
3177 the original versions.
3179 Bizhosting.com - giving a problem that fit basic design patterns.
3181 Earl Cahill - pushing the idea of more generic frameworks.
3183 Adam Erickson - design feedback, bugfixing, feature suggestions.
3185 James Lance - design feedback, bugfixing, feature suggestions.
3187 Krassimir Berov - feedback and some warnings issues with POD examples.
3191 This module may be distributed under the same terms as Perl itself.
3195 Paul Seamons <perl at seamons dot com>