什么是处理NoMethodError关联的好方法？
例如，假设我点击了一个类似 的 URL http://mysite.com/orders/ID_THAT_DOESNT_EXISTS/payments，我会收到一个异常抱怨，该异常#payments是在nil.
理想情况下，我会收到一条 Flash 消息，轻轻地通知用户具有所述 ID 的订单不存在。
更好的是，我很想将这一点推广到所有其他模型中。
这是一个示例OrdersController：
module Spree
module Admin
class OrdersController < Spree::Admin::BaseController
require 'spree/core/gateway_error'
before_filter :initialize_txn_partials
before_filter :initialize_order_events
before_filter :load_order, :only => [:show, :edit, :update, :fire, :resend, :history, :user]
respond_to :html
def index
params[:q] ||= {}
params[:q][:completed_at_not_null] ||= '1' if Spree::Config[:show_only_complete_orders_by_default]
@show_only_completed = params[:q][:completed_at_not_null].present?
params[:q][:s] ||= @show_only_completed ? 'completed_at desc' : 'created_at desc'
if !params[:q][:created_at_gt].blank?
params[:q][:created_at_gt] = Time.zone.parse(params[:q][:created_at_gt]).beginning_of_day rescue ""
end
if !params[:q][:created_at_lt].blank?
params[:q][:created_at_lt] = Time.zone.parse(params[:q][:created_at_lt]).end_of_day rescue ""
end
if @show_only_completed
params[:q][:completed_at_gt] = params[:q].delete(:created_at_gt)
params[:q][:completed_at_lt] = params[:q].delete(:created_at_lt)
end
@search = Order.ransack(params[:q])
@orders = @search.result.includes([:user, :shipments, :payments]).page(params[:page]).per(Spree::Config[:orders_per_page])
respond_with(@orders)
end
def show
respond_with(@order)
end
def new
@order = Order.create
respond_with(@order)
end
def edit
respond_with(@order)
end
def update
return_path = nil
if @order.update_attributes(params[:order]) && @order.line_items.present?
@order.update!
unless @order.complete?
# Jump to next step if order is not complete.
return_path = admin_order_customer_path(@order)
else
# Otherwise, go back to first page since all necessary information has been filled out.
return_path = admin_order_path(@order)
end
else
@order.errors.add(:line_items, t('errors.messages.blank')) if @order.line_items.empty?
end
respond_with(@order) do |format|
format.html do
if return_path
redirect_to return_path
else
render :action => :edit
end
end
end
end
def fire
# TODO - possible security check here but right now any admin can before any transition (and the state machine
# itself will make sure transitions are not applied in the wrong state)
event = params[:e]
if @order.send("#{event}")
flash.notice = t(:order_updated)
else
flash[:error] = t(:cannot_perform_operation)
end
rescue Spree::Core::GatewayError => ge
flash[:error] = "#{ge.message}"
ensure
respond_with(@order) { |format| format.html { redirect_to :back } }
end
def resend
OrderMailer.confirm_email(@order, true).deliver
flash.notice = t(:order_email_resent)
respond_with(@order) { |format| format.html { redirect_to :back } }
end
private
def load_order
@order ||= Order.find_by_number(params[:id], :include => :adjustments) if params[:id]
@order
end
# Allows extensions to add new forms of payment to provide their own display of transactions
def initialize_txn_partials
@txn_partials = []
end
# Used for extensions which need to provide their own custom event links on the order details view.
def initialize_order_events
@order_events = %w{cancel resume}
end
end
end
end