Passing an argument on request.referrer

Question

I'm building a site where a link to fill a new form can be clicked from an Event show page

<%= link_to 'Be a Contestant', new_form_path(:event_id => @event.id)%>

This creates a link like

http://localhost:3000/forms/new?event_id=2

Now if the form is filled with an error, when submitted, it returns an error

Couldn't find Event with 'id'=""

So I decided to use the request.referrer to redirect back to the previous page but it doesn't list the errors as use this method

def create
  @form = Form.new(form_params)

  respond_to do |format|
    if @form.save
      format.html { redirect_to @form, notice: 'Form was successfully created.' }
      format.json { render :show, status: :created, location: @form }
    else
      format.html { redirect_to request.referrer }
      format.json { render json: @form.errors, status: :unprocessable_entity }
    end
  end
end

I also tried this but to no avail.

def create
  @form = Form.new(form_params)

  respond_to do |format|
    if @form.save
      format.html { redirect_to @form, notice: 'Form was successfully created.' }
      format.json { render :show, status: :created, location: @form }
    else
      format.html { redirect_to new_form_path(:event_id => request.referrer.params[:event_id]) }
      format.json { render json: @form.errors, status: :unprocessable_entity }
    end
  end
end

Answer 1

What you probably really need to do is to add a hidden field event_id to the form because I'm betting that event_id doesn't get propagated from the #new to the #create action.

See here for more information on hidden_field_tag

Answer 2

You usually just render the edit view when there was an error in create :

def create
  @form = Form.new(form_params)

  respond_to do |format|
    if @form.save
      format.html { redirect_to @form, notice: 'Form was successfully created.' }
      format.json { render :show, status: :created, location: @form }
    else
      format.html { render :edit, alert: 'Error creating ...' }
      format.json { render json: @form.errors, status: :unprocessable_entity }
    end
  end
end