Ruby / Roda - Web Framework / Plugins / :json

Introduction

The :json plugin allows match blocks to return arrays or hashes, and have those arrays or hashes be converted to JSON which is used as the response body.

It also sets the response content type to application/json.

So you can take code like:

r.root do
  response['Content-Type'] = 'application/json'
  [1, 2, 3].to_json
end

r.is 'foo' do
  response['Content-Type'] = 'application/json'
  {'a'=>'b'}.to_json
end

and DRY it up:

plugin :json

r.root do
  [1, 2, 3]
end

r.is "foo" do
  { 'a' => 'b'}
end

By default, only arrays and hashes are handled, but you can specifically set the allowed classes to JSON by adding using the :classes option when loading the plugin:

plugin :json, classes: [Array, Hash, Sequel::Model]

By default objects are serialised with #.to_json, but you can pass in a custom serialiser, which can be any object that responds to #.call(object).

plugin :json, serializer: proc { |o| o.to_json(root: true) }

If you need the request information during serialisation, such as HTTP headers or query parameters, you can pass in the :include_request option, which will pass in the request object as the second argument when calling the serializer.

plugin :json, include_request: true, serializer: proc { |o, request| ... }

ClassMethods

`#.json_result_classes`

The classes that should be automatically converted to JSON