Check template file exists?

[fangyuan]

Hi, I have a problem that how to detect template file whether exists before render it.
In my Dancer app route service, like this:

get '/help/:subject' => { my $subject = param 'subject'; template sprintf('help/%s.tt', $subject); # will get 500 if cannot found template }

So, it could check template file exists before render it and avoid error 500. But I didnot find answer in template manual.
Any ideas? Thanks.

[lejeunerenard]

@fangyuan you can get the file path using Dancer's config sub to get the path to the views directory ( via config->{views} ) and concatenate the subject file name to that. With that file path you can check if the file exists using the build in -f perl file test function.

So all together your route would look like this:

get '/help/:subject' => {
  my $subject = param 'subject';
  my $tmpl = sprintf('help/%s.tt', $subject);
  if ( -f config->{ 'views' }.'/'.$tmpl ) {
    template $tmpl;
  } else {
    # Do something else instead of a 500
  }
}

[fangyuan]

@lejeunerenard, thanks for the suggestion, it is one both simple and quick solution.

There is another method, check template render result. If Dancer::Response returned, catch the error.

 my $response = template 'help/' . $subject;
 if (ref $response) { # Dancer::Response error
       if ($response->status == 500) {

       }
       #.....
       # normal output
       $response->status(200);
       return $response;
 }
 else { # normal output
        $response;
  }

[toddr]

Closing as answered query.