4.8 Creating Controllers ( Action Controller )

We had created a model. Now we will create a controller and 
afetr we will create the view.

The syntax to create a controller, according to the Rails rules 
to capitalize and use the singular form for the related 
model, for Hydrocarbon model is:

C:\ruby\organics\> ruby script/generate controller Hydrocarbon
C:\ruby\organics\> ruby script/generate controller Group

That creates the file:  
C:\ruby\organics\app\controllers\hydrocarbon_controller.rb
Now, we will set some definitions inside that file, as follows:


class HydrocarbonController < ApplicationController
	def list
	@hydrocarbons = Hydrocarbon.find(:all)
	end

	def display
	@hydrocarbon = Hydrocarbon.find(params[:id])
	end

	def display_groups
	@group = Group.find(params[:id])
	end
	
	def new
	@hydrocarbon = Hydrocarbon.new
	@groups = Group.find(:all)
	end

	def create
	@hydrocarbon = Hydrocarbon.new(params[:hydrocarbon])
	if @hydrocarbon.save
	redirect_to :action => 'list'
	else
	@groups = Group.find(:all)
	render :action => 'new'
	end
	end

	def edit
	@hydrocarbon = Hydrocarbon.find(params[:id])
	@groups = Group.find(:all)
	end

	def update
	@hydrocarbon = Hydrocarbon.find(params[:id])
	if @hydrocarbon.update_attributes(params[:hydrocarbon])
	redirect_to :action => 'display', :id => @hydrocarbon
	else
	@groups = Group.find(:all)
	render :action => 'edit'
	end
	end

	def remove
	Hydrocarbon.find(params[:id]).destroy
	redirect_to :action => 'list'
	end
	end