Brian Cooke

NAME

Catalyst::Plugin::CDBI::Transaction - Simple transaction handling for Catalyst apps that use Class::DBI models

SYNOPSIS

    # ... in your application class:
    package MyApp;

    use Catalyst qw/CDBI::Transaction/;

    # ... in a controller class:
    package MyApp::Controller::Foo;

    sub create_in_transaction : Local  {
        my ( $self, $c ) = @_;

        $c->transaction( sub { 
            MyApp::M::CDBI::Sometable->create({
                field_1 => 'value 1',
                field_2 => 'value 2',
            }); 
        } )
            or $c->log->error("Transaction failed: " . $c->error->[-1]);
    }

DESCRIPTION

Handle Catalyst::Model::CDBI database operations inside a transaction

METHODS

$c->transaction
$c->trans
$c->atomic

Pass a coderef to $c->transaction, and it will be executed atomically (inside of a transaction):

    $c->transaction( $ref_to_anonymous_subroutine );

Returns true and commits the transaction if all the statements inside the coderef were successful. Upon failure, adds the error message to $c->error, returns false and automatically rolls back the transaction.

This method was adapted from the idiom presented in the Class::DBI documentation, under the TRANSACTIONS heading.

$c->_cdbi_models

Called internally by $c->transaction to search all laoded components and return those that have a db_Main() method and where AutoCommit is not explicitly disabled. Caches the search result for subsequent calls. Returns an arrayref containing all the found components, or undef if none found.

NOTES/CAVEATS

All loaded model components used in the coderef passed to $c->transaction must have AutoCommit set to a true value. If AutoCommit is off for a connection, $c->transaction will not trigger commits or rollbacks on that connection, and you will need to take care of the commit yourself.

This plugin is intended for running the occasional transaction on a database connection that normally runs in AutoCommit mode. If you choose to run with AutoCommit off, then you probably should handle your transactions manually rather than with Catalyst::Plugin::CDBI::Transaction.

This plugin currently only works with Class::DBI models. It has been tested with Catalyst::Model::CDBI and Catalyst::Model::CDBI::Sweet.

Be careful when running this plugin under mod_perl. If the coderef passed to $c->transaction is from a named subroutine, mod_perl won't recompile that subroutine on each request, and thus will ignore future changes to the lexical variables outside the subroutine. This is probably not what you want. In summary, always pass an anonymous subroutine to $c->transaction, like in the SYNOPSIS above. And check your error logs for the infamous "won't stay shared" message. See the mod_perl docs, specifically "Understanding Closures", for more details.

SEE ALSO

Class::DBI (especially the TRANSACTIONS section), Catalyst

AUTHOR

Brian Cooke, mrkoffee@saltedsnail.com

LICENSE

This plugin is free software. You may redistribute or modify it under the same terms as Perl itself.




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