Rails 5 does not render JSON for create

Question

I have an API-only Rails 5 app.

My customers_controller_test fails with

ActionView::MissingTemplate: Missing template api/v1/customers/show, application/show with {:locale=>[:en], :formats=>[:html], :variants=>[], :handlers=>[:raw, :erb, :html, :builder, :ruby, :jbuilder]

I can't understand why.

The controller looks like this (Scaffold)

  # POST /customers
  # POST /customers.json
  def create
    @customer = Customer.new(customer_params)

    if @customer.save
      render :show, status: :created, location: api_v1_customer_url(@customer)
    else
      render json: @customer.errors, status: :unprocessable_entity
    end
  end

  # PATCH/PUT /customers/1
  # PATCH/PUT /customers/1.json
  def update
    if @customer.update(customer_params)
      render :show, status: :ok, location: api_v1_customer_url(@customer)
    else
      render json: @customer.errors, status: :unprocessable_entity
    end
  end

So why does POST return HTML when PUT correctly returns JSON?

The test passes fine with this change:

  # POST /customers
  # POST /customers.json
  def create
    @customer = Customer.new(customer_params)

    if @customer.save
      render json: 'show', status: :created, location: api_v1_customer_url(@customer)
    else
      render json: @customer.errors, status: :unprocessable_entity
    end
  end

Is anyone able to explain that?

Answer 1

Your code is trying to render a template

def create
  customer = Customer.new(customer_params)
  respond_to do |format|
    format.json do
      if customer.save
        render json: customer, status: :created, , location: api_v1_customer_url(@customer
      else
        render json: customer.errors, status: :unprocessable_entity
      end
    end
  end
end

Answer 2

The cause of the error is on this line:

render :show, status: :created, location: api_v1_customer_url(@customer)

calling render(:show) will tell rails to look for the "show" template and render it. Rails is looking for that template and can't find it, so it raises an error.

Antarr's answer provides a good solution. For your situation I would simplify it to the following, since I doubt you're supporting more than one response format for your API.

def create
  customer = Customer.new(customer_params)
  if customer.save
    render json: customer, status: :created
  else
    render json: customer.errors, status: :unprocessable_entity
  end
end

Note I also took out the location parameter because I'm not sure what it's supposed to do