How to build postman request for Rails POST method

Question

No matter how I format the raw portion of this request, I cannot avoid the parsing error below.

I have a Rails API with a create method that passes the spec, to illustrate that the controller message is sound:

describe "POST power_up" do

    let!(:client) { FactoryGirl.create :client, name: "joe", auth_token: "asdfasdfasdfasdfasdfasdf" }

    it "should create and save a new Power Up" do

      expect { post :create, format: :json, power_up: FactoryGirl.attributes_for(:power_up) }.to change(V1::PowerUp, :count).by(1)
    end

  end

I'm using Postman to try to POST to it. No matter what I try I'm getting the error:

Started POST "/v1/power_ups.json" for 127.0.0.1 at 2014-08-30 18:05:29 -0400
Error occurred while parsing request parameters.
Contents:

{
  'name': 'foo',
  'description': 'bar'
}


ActionDispatch::ParamsParser::ParseError (795: unexpected token at '{
  'name': 'foo',
  'description': 'bar'
}

Postman request setup:

I've also tried:

{
  'power_up': {
    'name': 'foo',
    'description': 'bar'
   }
}

Code from create method and strong parameters declaration in power_ups_controller.rb :

def create
    @power_up = PowerUp.new(power_up_params)

  if @power_up.save!
    redirect_to @power_up
  end
end

private

  def power_up_params
    params.require(:power_up).permit(:name, :description)
  end

Answer 1

Sorry bit too late to answer this but might help someone else.

All you need to do is - in your request header (in postman or whatever client) add

Content-Type = 'application/json'

Alternatively, you can also try it with curl (source):

curl -X POST -H "Content-Type: application/json" -d '{"power_up": { "name": "foo", "description": "bar" } }' 127.0.01:3000/v1/power_ups.json

Answer 2

Like @Tejas Patel said it's all about headers. But instead of setting them explicitly you can just:

1. In the request creation area switch to the body tab. Set raw radio button. In the lower text area input your body:

   { "power_up": { "name": "foo", "description": "bar" } }

2. Then in a dropdown list to the rigth choose JSON (application/json) option instead of the default Text option. That will auto-set the required headers. That's it - you can press "Send" button.

Answer 3

Single quotes (') are not actually the legal string delimiter in JSON: a string must be enclosed in double quotes ("). You can get away with it in the browser, since they are string delimiters in javascript. You can easily replicate this in an irb session

JSON.parse(%q[{'foo': 'bar'}]) #=> raises JSON::ParserError
JSON.parse(%q[{"foo": "bar"}]) #=> ok

In addition, given your spec you should be using the second form ie

{
  "power_up": {
    "name": "foo",
    "description": "bar"
   }
}