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

29 Feb 2012

      Fixed here : https://github.com/sukria/Dancer/pull/752

needs approval, inclusion and release in new stable.

In the meantime, you can apply on your Dancer installation and see if it
properly fixes your issue

thanks
dams

On 28 February 2012 09:26, damien krotkine <dkrotkine@gmail.com> wrote:
...
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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