Rails XML builder not rendering

问题

I’m having an issue rendering XML in the response body of a request in a Rails 4 application. In the example below the response body is blank. I’ve put a debugger in the template so I know it runs through it but doesn’t render anything out.

I created a simple rails app to demonstrate the issue I’m having using builder to return xml. Can anyone point me to the (probably stupid simple) problem with this example?

Here are the controller, template, and test:

controllers/bars_controller.rb

require 'builder'

class BarsController < ApplicationController
  before_action :set_bar, only: [:show]

  # GET /bars/1
  # GET /bars/1.json
  def show
    @xml = Builder::XmlMarkup.new
    render template: 'bars/show.xml.builder', formats: [:xml]
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_bar
      @bar = Bar.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def bar_params
      params.require(:bar).permit(:foo, :bar)
    end
 end

/views/bars/show.xml.builder

@xml.instruct!
@xml.bar do
  @xml.foo(@bar.foo)
  @xml.bar(@bar.bar)
end

/test/controllers/bars_controller_test.rb

 require 'test_helper'

 class BarsControllerTest < ActionController::TestCase
  setup do
    @bar = bars(:one)
  end

  test "should show bar" do
    get :show, id: @bar
    assert_response :success
    assert_match "<bar>", response.body
  end
 end

debugging session

     1: @xml.instruct!
     2: binding.pry
  => 3: @xml.bar do
     4:   @xml.foo(@bar.foo)
     5:   @xml.bar(@bar.bar)
     6: end

     [2] pry(#<#<Class:0x007fc669e9f610>>)> @xml.bar do
     [2] pry(#<#<Class:0x007fc669e9f610>>)*   @xml.foo(@bar.foo)  
     [2] pry(#<#<Class:0x007fc669e9f610>>)*   @xml.bar(@bar.bar)  
     [2] pry(#<#<Class:0x007fc669e9f610>>)* end  
      => "<?xml version=\"1.0\" encoding=\"UTF-8\"?><bar><foo>MyString</foo><bar>MyString</bar></bar>"

回答1:

It looks like creating the instance of the Builder::XmlMarkup.new is your problem. Remove the explicit creation of the builder so your controller looks like this:

def show
  # You can also simplify by removing "bars/"
  render 'bars/show.xml.builder', formats: [:xml]
end

And your view should look like this:

xml.instruct!
xml.bar do
  xml.foo(@bar.foo)
  xml.bar(@bar.bar)
end

来源：https://stackoverflow.com/questions/30078753/rails-xml-builder-not-rendering

标签

ruby-on-rails

xml

builder