class Praxis::MediaType
An Internet Media Type as defined in RFC 1590, as used in HTTP (see RFC 2616). As used in the Praxis
framework, media types also define the structure and content of entities of that type: the attributes that exist, their names and types.
An object with a media type can be represented on the wire using different structured-syntax encodings; for example, a controller might respond with an actual Widget object, but a Content-Type header specifying 'application/vnd.acme.widget+json'; Praxis
uses the information contained in the media-type definition of Widget to transform the object into an equivalent JSON representation. If the content type ends with '+xml' instead, and the XML handler is registered with the framework, Praxis
will respond with an XML representation of the widget. The use of media types allows your application's models to be decoupled from its HTTP interface specification.
A media type definition consists of:
- a MIME type identifier - attributes, each of which has a name and a data type - named links to other resources - named views, which expose interesting subsets of attributes
@example Declare a widget type that's used by my supply-chain management app
class MyApp::MediaTypes::Widget < Praxis::MediaType description 'Represents a widget' identifier 'application/vnd.acme.widget' attributes do attribute :id, Integer description: 'Database ID' attribute :href, Attributor::Href, description: 'Canonical resource refernece' attribute :color, String, example: 'red' attribute :material, String, description: 'Construction medium of the widget', values: ['copper', 'steel', 'aluminum'] attribute :factory, MyApp::MediaTypes::Factory, description: 'The factory in which this widget was produced' end links do link :factory, description: 'Link to the factory in which this widget was produced' end # If widgets can be linked-to by other resources, they should have a link view view :link do attribute :href end # All resources should have a default view view :default do attribute :id attribute :color attribute :material end end
Public Class Methods
# File lib/praxis/media_type.rb, line 71 def self._finalize! super # Only define our special links accessor if it was setup using the special DSL # (we might have an app defining an attribute called `links` on its own, in which # case we leave it be) if @attribute && self.attributes.key?(:links) && self.attributes[:links].type < Praxis::Links module_eval <<-RUBY, __FILE__, __LINE__ + 1 def links self.class::Links.new(@object) end RUBY end end
# File lib/praxis/media_type.rb, line 67 def self.attributes(opts={}, &block) super(opts.merge(dsl_compiler: MediaType::DSLCompiler), &block) end