How to prevent serialisation in one route in a perl dancer app? - perl

Question

I 've got a perl dancer app (providing a rest api) which works fine with JSON (de-)serialization.
Now I'm need one additional special route, that provides a (dynamically created) csv file for download.
Here is the sample code:
#!/usr/bin/env perl
use Dancer2;
set serializer => 'JSON';
get '/normal' => sub {
{ 'I say ' => 'the json serializer works' };
};
get '/download' => sub {
content_type 'text/csv';
return generateCsv();
};
sub generateCsv {
return '
1,2,3
4,5,6
';
}
dance;
The response sent to the client has no body, only a http-header (with the correct content-type)
$> curl -I http://localhost:3000/download
HTTP/1.0 200 OK
Date: Fri, 23 Mar 2018 10:10:14 GMT
Server: Perl Dancer2 0.205002
Server: Perl Dancer2 0.205002
Content-Length: 0
Content-Type: text/csv
The dancer serializer is not happy with this:
Failed to serialize content: hash- or arrayref expected
(not a simple scalar, use allow_nonref to allow this)
at /usr/local/share/perl/5.22.1/Dancer2/Serializer/JSON.pm line 40.
in /usr/local/share/perl/5.22.1/Dancer2/Core/Response.pm
I can't find anything about the allow_nonref thing in the Dancer docs or in the source code.
Has anybody a hint for me?

Answer 1

Use send_as:
get '/download' => sub {
send_as Mutable => generateCsv();
};

Answer 2

I've found that send_file also works:
get '/download' => sub {
send_file (\&generateCsv(), content_type => 'text/csv', filename => 'articleEbayStatus.csv');
};