update

class TasksController < ApplicationController
	# GET /tasks
	# GET /tasks.xml
  def index
    @tasks = Task.all

    respond_to do |format|
      tasks = @tasks.map {|task| json_for_task(task) }
      format.json { render :json => { :content => tasks } }
      format.html
      format.xml  { render :xml => @tasks }
    end
  end

	# GET /tasks/1
	# GET /tasks/1.xml
  def show
    @task = Task.find(params[:id])

    respond_to do |format|
      format.html # show.html.erb
      format.xml  { render :xml => @task }
      format.json do
        render :json => {
          :content => json_for_task(@task),
          :location => task_path(@task)
        }
      end
    end
  end

	# GET /tasks/new
	# GET /tasks/new.xml
	def new
		@task = Task.new

		respond_to do |format|
			format.html # new.html.erb
			format.xml	{ render :xml => @task }
		end
	end

	# GET /tasks/1/edit
	def edit
		@task = Task.find(params[:id])
	end

	# POST /tasks
	# POST /tasks.xml
  def create
    @task = Task.new(params[:task])

    respond_to do |format|
      if @task.save
        flash[:notice] = 'Task was successfully created.'
        format.json do
          render :json => { :content => json_for_task(@task) }, :status => :created,
                            :location => task_path(@task)
        end
        format.html { redirect_to(@task) }
        format.xml  { render :xml => @task, :status => :created, :location => @task }
      else
        format.html { render :action => "new" }
        format.xml  { render :xml => @task.errors, :status => :unprocessable_entity }
      end
    end
  end

	# PUT /tasks/1
	# PUT /tasks/1.xml
  def update
      @task = Task.find(params[:id])

      respond_to do |format|
        params[:task].delete(:guid)
        if @task.update_attributes(params[:task])
          flash[:notice] = 'Task was successfully updated.'
          format.json do
            render :json => { :content => json_for_task(@task) }, :location => task_path(@task)
          end
          format.html { redirect_to(@task) }
          format.xml  { head :ok }
        else
          format.html { render :action => "edit" }
          format.xml  { render :xml => @task.errors, :status => :unprocessable_entity }
        end
      end
    end

	# DELETE /tasks/1
	# DELETE /tasks/1.xml
  def destroy
    @task = Task.find(params[:id])
    @task.destroy

    respond_to do |format|
      format.json { head :ok }
      format.html { redirect_to(tasks_url) }
      format.xml  { head :ok }
    end
  end
	
	protected
		def json_for_task(task)
			{ :guid => task_path(task),
				:description => task.description,
				:isDone => task.isDone
			}
		end
end

Processing TasksController#update (for 127.0.0.1 at 2010-05-02 16:27:57) [PUT]
Parameters: {"isDone"=>false, "id"=>"10", "description"=>"jkjkj"}
Task Load (0.2ms) SELECT * FROM "tasks" WHERE ("tasks"."id" = 10)

NoMethodError (You have a nil object when you didn't expect it!
You might have expected an instance of ActiveRecord::Base.
The error occurred while evaluating nil.delete):
app/controllers/tasks_controller.rb:75:in update' app/controllers/tasks_controller.rb:74:inupdate'

Rendered rescues/_trace (73.4ms)
Rendered rescues/_request_and_response (0.3ms)
Rendering rescues/layout (internal_server_error)