=head1 NAME
-Catalyst::Manual::Tutorial::Debugging - Catalyst Tutorial - Part 7: Debugging
+Catalyst::Manual::Tutorial::Debugging - Catalyst Tutorial - Chapter 7: Debugging
=head1 OVERVIEW
-This is B<Part 7 of 10> for the Catalyst tutorial.
+This is B<Chapter 7 of 10> for the Catalyst tutorial.
L<Tutorial Overview|Catalyst::Manual::Tutorial>
=head1 DESCRIPTION
-This part of the tutorial takes a brief look at the primary options
+This chapter of the tutorial takes a brief look at the primary options
available for troubleshooting Catalyst applications.
Note that when it comes to debugging and troubleshooting, there are two
[% c.log.debug("This is a test log message") %]
+As with many other logging facilities, you a method is defined for
+each of the following "logging levels" (in increasing order of
+severity/importance):
+
+ $c->log->debug
+ $c->log->info
+ $c->log->warn
+ $c->log->error
+ $c->log->fatal
+
You can also use L<Data::Dumper|Data::Dumper> in both Catalyst code
(C<use Data::Dumper; $c-E<gt>log-E<gt>debug("\$var is: ".Dumper($var));)>)
and TT templates (C<[% Dumper.dump(book) %]>.
# Retrieve all of the book records as book model objects and store in the
# stash where they can be accessed by the TT template
- $c->stash->{books} = [$c->model('DB::Books')->all];
+ $c->stash->{books} = [$c->model('DB::Book')->all];
# Set the TT template to use. You will almost always want to do this
# in your action methods.
B<NOTE:> The C<DB> here is the Perl Debugger, not the DB model.
+If you haven't done it already, enable SQL logging as before:
+
+ $ export DBIC_TRACE=1
+
To now run the Catalyst development server under the Perl debugger, simply
prepend C<perl -d> to the front of C<script/myapp_server.pl>:
$ perl -d script/myapp_server.pl
- Loading DB routines from perl5db.pl version 1.27
+ Loading DB routines from perl5db.pl version 1.3
Editor support available.
Enter h or `h h' for help, or `man perldebug' for more help.
- main::(script/myapp_server.pl:14): my $debug = 0;
+ main::(script/myapp_server.pl:16): my $debug = 0;
DB<1>
C<MyApp::Controller::list> method, the console session running the
development server will drop to the Perl debugger prompt:
- MyApp::Controller::Books::list(/home/me/MyApp/script/../lib/MyApp/Controller/Books.pm:40):
- 40: $c->stash->{books} = [$c->model('DB::Books')->all];
+ MyApp::Controller::Books::list(/home/me/MyApp/script/../lib/MyApp/Controller/Books.pm:48):
+ 48: $c->stash->{books} = [$c->model('DB::Book')->all];
DB<1>
C<single-step> into methods/subroutines):
DB<1> n
- SELECT me.id, me.authors, me.title, me.rating FROM books me:
- MyApp::Controller::Books::list(/home/me/MyApp/script/../lib/MyApp/Controller/Books.pm:44):
- 44: $c->stash->{template} = 'books/list.tt2';
+ SELECT me.id, me.title, me.rating, me.created, me.updated FROM book me:
+ MyApp::Controller::Books::list(/home/me/MyApp/script/../lib/MyApp/Controller/Books.pm:53):
+ 53: $c->stash->{template} = 'books/list.tt2';
DB<1>
Next, list the methods available on our C<Book> model:
- DB<1> m $c->model('DB::Books')
+ DB<1> m $c->model('DB::Book')
()
(0+
(bool
- MODIFY_CODE_ATTRIBUTES
- _attr_cache
- _collapse_result
- _construct_object
- _count
- _result_class_accessor
- _result_source_accessor
- all
- carp
+ __result_class_accessor
+ __source_handle_accessor
+ _add_alias
+ __bool
+ _build_unique_query
+ _calculate_score
+ _collapse_cond
<lines removed for brevity>
DB<2>
We can also play with the model directly:
- DB<2> x ($c->model('DB::Books')->all)[1]->title
- SELECT me.id, me.title, me.rating FROM books me:
+ DB<2> x ($c->model('DB::Book')->all)[1]->title
+ SELECT me.id, me.title, me.rating, me.created, me.updated FROM book me:
0 'TCP/IP Illustrated, Volume 1'
This uses the Perl debugger C<x> command to display the title of a book.
0 ARRAY(0xa8f3b7c)
0 MyApp::Model::DB::Book=HASH(0xb8e702c)
'_column_data' => HASH(0xb8e5e2c)
+ 'created' => '2009-05-08 10:19:46'
'id' => 1
'rating' => 5
'title' => 'CCSP SNRS Exam Certification Guide'
+ 'updated' => '2009-05-08 10:19:46'
'_in_storage' => 1
<lines removed for brevity>
Finally, press C<Ctrl+C> to break out of the development server.
Because we are running inside the Perl debugger, you will drop to the
-debugger prompt. Press C<q> to exit the debugger and return to your OS
+debugger prompt.
+
+ ^CCatalyst::Engine::HTTP::run(/usr/local/share/perl/5.10.0/Catalyst/Engine/HTTP.pm:260):
+ 260: while ( accept( Remote, $daemon ) ) {
+
+ DB<4>
+
+Finally, press C<q> to exit the debugger and return to your OS
shell prompt:
DB<4> q
$
For more information on using the Perl debugger, please see C<perldebug>
-and C<perldebtut>. You can also type C<h> or C<h h> at the debugger
-prompt to view the built-in help screens.
+and C<perldebtut>. For those daring souls out there, you can dive down
+even deeper into the magical depths of this fine debugger by checking
+out C<perldebguts>.
+
+You can also type C<h> or C<h h> at the debugger prompt to view the
+built-in help screens.
+
+For an excellent book covering all aspects of the Perl debugger, we highly
+recommend reading 'Pro Perl Debugging' by Richard Foley.
+Oh yeah, before you forget, be sure to remove the C<DB::single=1> line you
+added above in C<lib/MyApp/Controller/Books.pm>.
=head1 DEBUGGING MODULES FROM CPAN
mkdir -p lib/Module; cp `perldoc -l Module::Name` lib/Module/
-Note: If you are following along in Ubuntu, you will need to install
-the C<perl-doc> package to use the C<perldoc> command. Use
-C<sudo apt-get install perl-doc> to do that.
+Note: If you are following along in Debian 5 or Ubuntu, you will
+need to install the C<perl-doc> package to use the C<perldoc> command.
+Use C<sudo aptitude install perl-doc> to do that.
For example, you could make a copy of
L<Catalyst::Plugin::Authentication|Catalyst::Plugin::Authentication>
'print $Catalyst::Plugin::Authentication::VERSION;'
0.07
+and if you are using bash aliases:
+
+ alias pmver="perl -le '\$m = shift; eval qq(require \$m) \
+ or die qq(module \"\$m\" is not installed\\n); \
+ print \$m->VERSION'"
+
=item *
Check if a modules contains a given method:
enabled will conflict with several of the conventions used by this
tutorial to leave some variables undefined on purpose).
+Happy debugging.
=head1 AUTHOR
projects / catagits/Catalyst-Manual.git / blobdiff