X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=catagits%2FCatalyst-Manual.git;a=blobdiff_plain;f=lib%2FCatalyst%2FManual%2FTutorial%2FBasicCRUD.pod;h=9d6f6b51120e8ff221335265b2b90e24c5a65096;hp=8c524c7407d7b25a54dcdf048e749058bcc76a39;hb=fe01b24f85098a731125f36fc4de26a654ac7efc;hpb=5e6026272f809951ac22fae43b73d2c1dc79c7fc diff --git a/lib/Catalyst/Manual/Tutorial/BasicCRUD.pod b/lib/Catalyst/Manual/Tutorial/BasicCRUD.pod index 8c524c7..9d6f6b5 100644 --- a/lib/Catalyst/Manual/Tutorial/BasicCRUD.pod +++ b/lib/Catalyst/Manual/Tutorial/BasicCRUD.pod @@ -1,11 +1,11 @@ =head1 NAME -Catalyst::Manual::Tutorial::BasicCRUD - Catalyst Tutorial - Part 3: Basic CRUD +Catalyst::Manual::Tutorial::BasicCRUD - Catalyst Tutorial - Part 4: Basic CRUD =head1 OVERVIEW -This is B for the Catalyst tutorial. +This is B for the Catalyst tutorial. L @@ -21,57 +21,69 @@ L =item 3 -B +L =item 4 -L +B =item 5 -L +L =item 6 -L +L =item 7 -L +L =item 8 -L +L =item 9 +L + +=item 10 + L =back - =head1 DESCRIPTION This part of the tutorial builds on the fairly primitive application -created in Part 2 to add basic support for Create, Read, Update, and +created in Part 3 to add basic support for Create, Read, Update, and Delete (CRUD) of C objects. Note that the 'list' function in Part 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 capabilities, including full Update functionality, will be addressed in -Part 8. +Part 9. + +Although this part of the tutorial will show you how to build CRUD +functionality yourself, another option is to use a "CRUD builder" type +of tool to automate the process. You get less control, but it's quick +and easy. For example, see +L, +L, and +L. You can checkout the source code for this example from the catalyst subversion repository as per the instructions in -L +L. + =head1 FORMLESS SUBMISSION -Our initial attempt at object creation will utilize the "URL arguments" -feature of Catalyst (we will employ the more common form-based -submission in the sections that follow). +Our initial attempt at object creation will utilize the "URL +arguments" feature of Catalyst (we will employ the more common form- +based submission in the sections that follow). =head2 Include a Create Action in the Books Controller @@ -93,7 +105,7 @@ Edit C and enter the following method: # 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({ + my $book = $c->model('DB::Books')->create({ title => $title, rating => $rating }); @@ -160,7 +172,7 @@ Edit C and then enter: [% # Provide a link back to the list page -%] [% # 'uri_for()' builds a full URI; e.g., 'http://localhost:3000/books/list' -%] -

Return to list

+

Return to list

[% # Try out the TT Dumper (for development only!) -%] 
@@ -168,22 +180,20 @@ Edit C and then enter:
     [% Dumper.dump(book) %]
-The TT C 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 -"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 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 "pretty printing" of objects and +variables. Other than that, the rest of the code should be familiar +from the examples in Part 3. -B As mentioned earlier, the C view -class created by TTSite redefines the name used to access the Catalyst -context object in TT templates from the usual C to C. =head2 Try the C Feature If the application is still running from before, use C to kill it. Then restart the server: - $ script/myapp_server.pl + $ DBIC_TRACE=1 script/myapp_server.pl Note that new path for C appears in the startup debug output. @@ -202,7 +212,7 @@ Next, use your browser to enter the following URL: Your browser should display " Added book 'TCPIP_Illustrated_Vol-2' by 'Stevens' with a rating of 5." along with a dump of the new book model object. You should also see the following DBIC debug messages displayed -in the development server log messages: +in the development server log messages if you have DBIC_TRACE set: INSERT INTO books (rating, title) VALUES (?, ?): `5', `TCPIP_Illustrated_Vol-2' INSERT INTO book_authors (author_id, book_id) VALUES (?, ?): `4', `6' @@ -214,9 +224,9 @@ The C statements are obviously adding the book and linking it to the existing record for Richard Stevens. The C Rating: @@ -274,6 +285,7 @@ Open C in your editor and enter: Note that we have specified the target of the form data as C, the method created in the section that follows. + =head2 Add a Method to Process Form Values and Update Database Edit C and add the following method to @@ -294,7 +306,7 @@ save the form information to the database: my $author_id = $c->request->params->{author_id} || '1'; # Create the book - my $book = $c->model('MyAppDB::Book')->create({ + my $book = $c->model('DB::Books')->create({ title => $title, rating => $rating, }); @@ -322,13 +334,13 @@ it. Then restart the server: Point your browser to L and enter "TCP/IP Illustrated, Vol 3" for the title, a rating of 5, and an -author ID of 4. You should then be forwarded to the same +author ID of 4. You should then see the output of the same C template seen in earlier examples. Finally, click "Return to list" to view the full list of books. B Having the user enter the primary key ID for the author is obviously crude; we will address this concern with a drop-down list in -Part 8. +Part 9. =head1 A SIMPLE DELETE FEATURE @@ -376,22 +388,31 @@ and 2) the four lines for the Delete link near the bottom). [% # Add a link to delete a book %] - Delete + Delete [% END -%] -The additional code is obviously designed to add a new column to the -right side of the table with a C "button" (for simplicity, links -will be used instead of full HTML buttons). +The additional code is obviously designed to add a new column to the +right side of the table with a C "button" (for simplicity, +links will be used instead of full HTML buttons). + +B You should use more than just a simple link with your +applications. Consider using some sort of of confirmation page +(typically with unique actions in your controller for both the +confirmation and the actual delete operation). Also, you should try +to use an HTTP POST operation (versus the GET used here) for +operations that change the state of your application (e.g., the +database). + =head2 Add a Delete Action to the Controller Open C in your editor and add the following method: - =head2 delete + =head2 delete Delete a book @@ -402,7 +423,7 @@ following method: my ($self, $c, $id) = @_; # Search for the book and then delete it - $c->model('MyAppDB::Book')->search({id => $id})->delete_all; + $c->model('DB::Books')->search({id => $id})->delete_all; # Set a status message to be displayed at the top of the view $c->stash->{status_msg} = "Book deleted."; @@ -444,7 +465,7 @@ along with a list of the eight remaining books. =head2 Fixing a Dangerous URL -Note the URL in your browser once you have performed the deletetion in the +Note the URL in your browser once you have performed the deletion in the prior step -- it is still referencing the delete action: http://localhost:3000/books/delete/6 @@ -456,7 +477,7 @@ could clearly be extremely dangerous. We can improve the logic by converting to a redirect. Unlike C<$c-Eforward('list'))> or C<$c-Edetach('list'))> that perform a server-side alteration in the flow of processing, a redirect is a -client-side mechanism that causes the brower to issue an entirely +client-side mechanism that causes the browser to issue an entirely new request. As a result, the URL in the browser is updated to match the destination of the redirection URL. @@ -475,7 +496,7 @@ C method to match: my ($self, $c, $id) = @_; # Search for the book and then delete it - $c->model('MyAppDB::Book')->search({id => $id})->delete_all; + $c->model('DB::Books')->search({id => $id})->delete_all; # Set a status message to be displayed at the top of the view $c->stash->{status_msg} = "Book deleted."; @@ -488,18 +509,20 @@ C method to match: =head2 Try the Delete and Redirect Logic Restart the development server and point your browser to -L. Delete the first copy of -"TCPIP_Illustrated_Vol-2", but notice that I. Because the stash is reset on every -request (and a redirect involves a second request), the -C is cleared before it can be displayed. +L and delete the first copy of +"TCPIP_Illustrated_Vol-2". The URL in your browser should return to +the L URL, so that is an +improvement, but notice that I. Because the stash is reset on every request (and a +redirect involves a second request), the C is cleared +before it can be displayed. =head2 Using C to Pass Query Parameters There are several ways to pass information across a redirect. In general, the best option is to use the C technique that we -will see in Part 4 of the tutorial; however, here we will pass the +will see in Part 5 of the tutorial; however, here we will pass the information via query parameters on the redirect itself. Open C and update the existing C method to match the following: @@ -515,7 +538,7 @@ C method to match the following: my ($self, $c, $id) = @_; # Search for the book and then delete it - $c->model('MyAppDB::Book')->search({id => $id})->delete_all; + $c->model('DB::Books')->search({id => $id})->delete_all; # Redirect the user back to the list page with status msg as an arg $c->response->redirect($c->uri_for('/books/list', @@ -524,18 +547,23 @@ C method to match the following: This modification simply leverages the ability of C to include an arbitrary number of name/value pairs in a hash reference. Next, we -need to update C to handle C as a +need to update C to handle C as a query parameter: - - + ...
- [% status_msg || Catalyst.request.params.status_msg %] - [% error_msg %] - [% content %] -
- - + [%# Status and error messages %] + [% status_msg || c.request.params.status_msg %] + [% error_msg %] + [%# This is where TT will stick all of your template's contents. -%] + [% content %] + + ... + +Although the sample above only shows the C div, leave the +rest of the file intact -- the only change we made to the C +was to add "C<|| c.request.params.status_msg>" to the +Cspan class="message"E> line. =head2 Try the Delete and Redirect With Query Param Logic @@ -561,8 +589,8 @@ Kennedy Clark, C Please report any errors, issues or suggestions to the author. The most recent version of the Catalyst Tutorial can be found at -L. +L. -Copyright 2006, Kennedy Clark, under Creative Commons License -(L). +Copyright 2006-2008, Kennedy Clark, under Creative Commons License +(L).