=item 9
-L<Appendicies|Catalyst::Manual::Tutorial::Appendicies>
+L<Appendices|Catalyst::Manual::Tutorial::Appendices>
=back
This part of the tutorial builds on the fairly primitive application
created in Part 2 to add basic support for Create, Read, Update, and
Delete (CRUD) of C<Book> objects. Note that the 'list' function in Part
-2 already implements the Read portion of Crud (although Read normally
+2 already implements the Read portion of CRUD (although Read normally
refers to reading a single object; you could implement full read
functionality using the techniques introduced below). This section will
focus on the Create and Delete aspects of CRUD. More advanced
pulled from the Catalyst Subversion repository in one step with the
following command:
- svn checkout http://dev.catalyst.perl.org/repos/Catalyst/trunk/examples/Tutorial@###
- IMPORTANT: Does not work yet. Will be completed for final version.
-
+ svn co http://dev.catalyst.perl.org/repos/Catalyst/tags/examples/Tutorial/5.7X/BasicCRUD MyApp
=head1 FORMLESS SUBMISSION
=head2 url_create
- Create a book with the supplied title, rating and author
+ Create a book with the supplied title, rating, and author
=cut
sub url_create : Local {
- # In addition to self & context, get the title, rating & author_id args
- # from the URL. Note that Catalyst automatically puts extra information
- # after the "/<controller_name>/<action_name/" into @_
+ # In addition to self & context, get the title, rating, &
+ # author_id args from the URL. Note that Catalyst automatically
+ # puts extra information after the "/<controller_name>/<action_name/"
+ # into @_
my ($self, $c, $title, $rating, $author_id) = @_;
# Call create() on the book model object. Pass the table
# columns/field values we want to set as hash values
my $book = $c->model('MyAppDB::Book')->create({
- title => $title,
- rating => $rating
+ title => $title,
+ rating => $rating
});
# Add a record to the join table for this book, mapping to
[% # optional, but prevents "massive indenting" of deeply nested objects -%]
[% USE Dumper(Indent=1) -%]
- [% # Set the page title -%]
+ [% # Set the page title. META can 'go back' and set values in templates -%]
+ [% # that have been processed 'before' this template (here it's for -%]
+ [% # root/lib/site/html and root/lib/site/header). Note that META on -%]
+ [% # simple strings (e.g., no variable interpolation). -%]
[% META title = 'Book Created' %]
- [% # Output information about the record that was added. Note use -%]
- [% # of 'first' to only list the first author (if > 1 author). -%]
- <p>Added book '[% book.title %]' by '[% book.authors.first.last_name %]'
+ [% # Output information about the record that was added. First title. -%]
+ <p>Added book '[% book.title %]'
+
+ [% # Output the last name of the first author. This is complicated by an -%]
+ [% # issue in TT 2.15 where blessed hash objects are not handled right. -%]
+ [% # First, fetch 'book.authors' from the DB once. -%]
+ [% authors = book.authors %]
+ [% # Now use IF statements to test if 'authors.first' is "working". If so, -%]
+ [% # we use it. Otherwise we use a hack that seems to keep TT 2.15 happy. -%]
+ by '[% authors.first.last_name IF authors.first;
+ authors.list.first.value.last_name IF ! authors.first %]'
+
+ [% # Output the rating for the book that was added -%]
with a rating of [% book.rating %].</p>
[% # Provide a link back to the list page -%]
[% # 'uri_for()' builds a full URI; e.g., 'http://localhost:3000/books/list' -%]
<p><a href="[% Catalyst.uri_for('/books/list') %]">Return to list</a></p>
- [% # Try out the TT Dumper -%]
+ [% # Try out the TT Dumper (for development only!) -%]
<pre>
Dump of the 'book' variable:
[% Dumper.dump(book) %]
</pre>
-The TT C<USE> directive allows access to a variety of plugin modules (we
-are talking TT plugins here, not Catalyst plugins) to add extra
-functionality to the base TT capabilities. Here, the plugin allows
-L<Data::Dumper|Data::Dumper> "pretty printing" of objects and variables.
-Other than that, the rest of the code should be familiar from the
-examples in Part 2.
+The TT C<USE> directive allows access to a variety of plugin modules (TT
+plugins, that is, not Catalyst plugins) to add extra functionality to
+the base TT capabilities. Here, the plugin allows L<Data::Dumper>
+"pretty printing" of objects and variables. Other than that, the rest
+of the code should be familiar from the examples in Part 2.
B<IMPORTANT NOTE> As mentioned earlier, the C<MyApp::View::TT.pm> view
class created by TTSite redefines the name used to access the Catalyst
context object in TT templates from the usual C<c> to C<Catalyst>.
-
=head2 Try the C<url_create> Feature
If the application is still running from before, use C<Ctrl-C> to kill
-it. Then restart the server:
+it. Then restart the server:
$ script/myapp_server.pl
B<TIP>: You can use C<script/myapp_server.pl -r> to have the development
server auto-detect changed files and reload itself (if your browser acts
odd, you should also try throwing in a C<-k>). If you make changes to
-just the TT templates, you do not need to reload the development server
+the TT templates only, you do not need to reload the development server
(only changes to "compiled code" such as Controller and Model C<.pm>
files require a reload).
C</books/list> page).
-
=head1 MANUALLY BUILDING A CREATE FORM
Although the C<url_create> action in the previous step does begin to
$c->stash->{template} = 'books/form_create.tt2';
}
-This action merely invokes a view containing a book creation form.
-
+This action simply invokes a view containing a book creation form.
=head2 Add a Template for the Form
Open C<root/src/books/form_create.tt2> in your editor and enter:
- [% META title = 'Book Create' -%]
+ [% META title = 'Manual Form Book Create' -%]
<form method="post" action="[% Catalyst.uri_for('form_create_do') %]">
<table>
Note that we have specified the target of the form data as
C<form_create_do>, the method created in the section that follows.
-
=head2 Add Method to Process Form Values and Update Database
Edit C<lib/MyApp/Controller/Books.pm> and add the following method to
-save the form information to the databse:
+save the form information to the database:
=head2 form_create_do
# Store new model object in stash
$c->stash->{book} = $book;
- # Avoid Data::Dumper issue mention earlier
+ # Avoid Data::Dumper issue mentioned earlier
# You can probably omit this
$Data::Dumper::Useperl = 1;
=head2 Test Out The Form
-If the application is still running from before, use C<Ctrl-C> to kill it. Then restart the server:
+If the application is still running from before, use C<Ctrl-C> to kill
+it. Then restart the server:
$ script/myapp_server.pl
"Return to list" to view the full list of books.
B<Note:> Having the user enter the primary key ID for the author is
-obviously a bit crude; we will address this concern with a drop-down
-list in Part 8.
-
-
+obviously crude; we will address this concern with a drop-down list in
+Part 8.
=head1 A SIMPLE DELETE FEATURE
<td>[% book.title %]</td>
<td>[% book.rating %]</td>
<td>
- [% # Print author count in parens. 'book.authors' uses the 'many_to_many' -%]
- [% # relationship to retrieve all of the authors of a book. 'size' is a -%]
- [% # TT VMethod to get the number of elements in a list. -%]
- ([% book.authors.size %])
- [% # Use an alternate form of a FOREACH loop to display authors. -%]
- [% # _ below is the TT string concatenation operator. -%]
- [% author.last_name _' ' FOREACH author = book.authors %]
- [% # Note: if many_to_many relationship not used in Authors.pm, you could -%]
- [% # have used the following to 'walk' through the 'join table objects' -%]
- [% # bk_author.author.last_name _' ' FOREACH bk_author = book.book_authors %]
+ [% # First initialize a TT variable to hold a list. Then use a TT FOREACH -%]
+ [% # loop in 'side effect notation' to load just the last names of the -%]
+ [% # authors into the list. Note that the 'push' TT vmethod does not -%]
+ [% # a value, so nothing will be printed here. But, if you have something -%]
+ [% # in TT that does return a method and you don't want it printed, you -%]
+ [% # can: 1) assign it to a bogus value, or 2) use the CALL keyword to -%]
+ [% # call it and discard the return value. -%]
+ [% tt_authors = [ ];
+ tt_authors.push(author.last_name) FOREACH author = book.authors %]
+ [% # Now use a TT 'virtual method' to display the author count -%]
+ ([% tt_authors.size %])
+ [% # Use another TT vmethod to join & print the names & comma separators -%]
+ [% tt_authors.join(', ') %]
</td>
<td>
[% # Add a link to delete a book %]
right side of the table with a C<Delete> "button" (for simplicity, links
will be used instead of full HTML buttons).
-
=head2 Add a Delete Action to the Controller
Open C<lib/MyApp/Controller/Books.pm> in your editor and add the
following method:
- =head2 Delete
+ =head2 delete
Delete a book
Kennedy Clark, C<hkclark@gmail.com>
-Please report any errors, issues or suggestions to the author.
+Please report any errors, issues or suggestions to the author. The
+most recent version of the Catalyst Tutorial can be found at
+L<http://dev.catalyst.perl.org/repos/Catalyst/trunk/Catalyst-Runtime/lib/Catalyst/Manual/Tutorial/>.
Copyright 2006, Kennedy Clark, under Creative Commons License
(L<http://creativecommons.org/licenses/by-nc-sa/2.5/>).
-Version: .94
-
projects / catagits/Catalyst-Runtime.git / blobdiff