Dancer::Serializer::Mutable(3) Serialize and deserialize content using the appropriate HTTP header


version 1.3202


# in config.yml
serializer: Mutable
# in the app
put '/something' => sub {
# deserialized from request
my $name = param( 'name' );

# will be serialized to the most
# fitting format
return { message => "user $name added" };


This serializer will try find the best (de)serializer for a given request. For this, it will pick the first content type found from the following list and use its related serializer.
  • The content_type from the request headers
  • the content_type parameter from the URL
  • the accept from the request headers
  • The default is application/json

The content-type/serializer mapping that "Dancer::Serializer::Mutable" uses is

    serializer               | content types
    Dancer::Serializer::YAML | text/x-yaml, text/html
    Dancer::Serializer::XML  | text/xml
    Dancer::Serializer::JSON | text/x-json, application/json


template_or_serialize( $template, $data, $options )

For instances where you want to render a template for normal browser requests, and return serialized content for AJAX calls.

If the requested content-type is text/html, "template_or_serialize" returns the rendered template, else it returns $data unmodified (which will then be serialized as usual).

"template_or_serialize" is not exported by default.

    use Dancer::Serializer::Mutable qw/ template_or_serialize /;
    get '/greetings' => sub {
        return template_or_serialize 'greetings' => {
            title => $title,
            name  => $name,


The following methods are used internally by "Dancer" and are not made accessible via the DSL.


Serialize a data structure. The format it is serialized to is determined automatically as described above. It can be one of YAML, XML, JSON, defaulting to JSON if there's no clear preference from the request.


Deserialize the provided serialized data to a data structure. The type of serialization format depends on the request's content-type. For now, it can be one of YAML, XML, JSON.


Returns the content-type that was used during the last "serialize" / "deserialize" call. WARNING : you must call "serialize" / "deserialize" before calling "content_type". Otherwise the return value will be "undef".


Dancer Core Developers


This software is copyright (c) 2010 by Alexis Sukrieh.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.