Rails 4 example of strong_parameters. This is the new way of doing controllers and whitelisting parameters.

strong_parameters_example.rb

class HeadlinesController < ApplicationController
  before_action :set_headline, only: [:show, :edit, :update, :destroy]

  # GET /headlines
  # GET /headlines.json
  def index
    @headlines = Headline.all

    respond_to do |format|
      format.html # index.html.erb
      format.json { render json: @headlines }
    end
  end

  # GET /headlines/1
  # GET /headlines/1.json
  def show
    respond_to do |format|
      format.html # show.html.erb
      format.json { render json: @headline }
    end
  end

  # GET /headlines/new
  # GET /headlines/new.json
  def new
    @headline = Headline.new

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @headline }
    end
  end

  # GET /headlines/1/edit
  def edit
  end

  # POST /headlines
  # POST /headlines.json
  def create
    @headline = Headline.new(headline_params)

    respond_to do |format|
      if @headline.save
        format.html { redirect_to @headline, notice: 'Headline was successfully created.' }
        format.json { render json: @headline, status: :created, location: @headline }
      else
        format.html { render action: "new" }
        format.json { render json: @headline.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /headlines/1
  # PATCH/PUT /headlines/1.json
  def update
    respond_to do |format|
      if @headline.update_attributes(headline_params)
        format.html { redirect_to @headline, notice: 'Headline was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: "edit" }
        format.json { render json: @headline.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /headlines/1
  # DELETE /headlines/1.json
  def destroy
    @headline.destroy

    respond_to do |format|
      format.html { redirect_to headlines_url }
      format.json { head :no_content }
    end
  end

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

    # Use this method to whitelist the permissible parameters. Example:
    #   params.require(:person).permit(:name, :age)
    #
    # Also, you can specialize this method with per-user checking of permissible
    # attributes.
    def headline_params
      params.require(:headline).permit(:title, :body, :published_date, :available)
    end
end