Header links

controller.rb

class Catalogs < Controller
  
  set :model, Catalog
  set :fields, [:title, :description]
  
  namespace '/' do
    
    get do
      catalogs = model.paginate(page, page_size)
      
      etag catalogs.etag
      last_modified catalogs.last_modified
      
      link url('/'), rel: 'self', title: 'Catalog Index'
      pagination_links(catalogs)
      
      yajl :'catalogs/index', locals: {catalogs: catalogs}
    end
    
    post do
      catalog.set_fields params, settings.fields
      catalog.save
      
      headers 'Location' => url(catalog.id)
      
      204
    end
    
    namespace ':id' do
      
      before do
        catalog or not_found
        
        etag catalog.etag
        last_modified catalog.last_modified
      end
      
      get do
        link url(catalog.id), rel: 'self', title: catalog.title
        link url('/'), rel: 'collection', title: 'Return to Index'
        
        yajl :'catalogs/show'
      end
      
      put do
        catalog.update_fields params, settings.fields, missing: :skip
        
        headers 'Location' => url(catalog.id)
        
        204
      end
      
      delete do
        catalog.destroy
        
        204
      end
      
      def catalog
        @catalog ||= model[id]
      end
    end
    
    def catalog
      @catalog ||= model.new
    end
    
    error Sequel::ValidationFailed do
      [
        400, 
        yajl(:error, locals: {title: 'validation error', message: catalog.errors.full_messages})
      ]
    end
  end
end