Re: [Dancer-users] raising exceptions in hooks.

28 Feb 2012

      Hi,

Thanks for using exceptions :)

I'm having a look at this issue. There is indeed a "catch all" mechanism to
produce a Dancer::halt in case of any issue in hooks. I'll make it more
flexible.

On 28 February 2012 05:22, Rusty Conover <rconover@infogears.com> wrote:
...
Hi Everyone,
I'm trying to use a hook like:
register_exception('DatabaseProblem', message_pattern => "Database
problem: %s");
hook 'database_error' => sub {
 my $message = Carp::longmess($_[0]);
 my $handle = shift;
 raise DatabaseProblem => $message;
 return;
};
This is documented in Dancer::Plugin::Database.
To raise a DatabaseProblem exception in the event of a database error such
as:
my $dbh = database();
try {
  $dbh->do("insert into table_that_does_not_exist values(?)", undef,
"yes");
} catch {
  my ($exception) = @_;
  if ($exception->does('DatabaseProblem') {
      # do something
  }
};
The problem I'm getting is:
An error occured while executing the filter named database_error:
It seems we can't raise an exception in the database_error hook or any
hook really, without having it generate a 500 error because Dancer::Hook
catches all exceptions thrown in hooks and halts rendering.
Relevant excerpt from Hook.pm:
my $compiled_filter = sub {
     my @arguments = @_;
     return if Dancer::SharedData->response->halted;
my $app = Dancer::App->current();
     return unless $properties->should_run_this_app($app->name);
Dancer::Logger::core( "entering " . $hook_name . " hook" );
try { $code->(@arguments) }
     catch {
         my ($exception) = @_;
         # exception is not a workflow continuation but a genuine error
         my $err = Dancer::Error->new(
             code    => 500,
             title   => $hook_name . ' filter error',
             message => "An error occured while executing the filter named
$hook_name: $exception",
             exception => $exception,
         );
         # raise a new halt exception
         Dancer::halt( $err->render );
     };
 };
Can we change this so exceptions can be raised from hooks, or is there
another pattern I should be using to catch DBI errors?
Many thanks,
Rusty
--
InfoGears Inc.
http://www.infogears.com
http://www.gearbuyer.com
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Re: [Dancer-users] raising exceptions in hooks.

damien krotkine