display error messages in some case raise exception

venshop_app/app/assets/stylesheets/custom.css.scss

@@ -469,3 +469,7 @@ footer {
 .block-search-result {
   padding-top: 10px;
 }
+
+#block-message-visible {
+  margin-top: 10px;
+}

venshop_app/app/controllers/cards_controller.rb

@@ -51,12 +51,14 @@ class CardsController < ApplicationController
         # if add a product to card
         # first time add to card
         if @card_infos.empty?
+          if Product.exists?(params[:product_id])
             product = Product.find(params[:product_id])
             card_items = Array.new
             card_items.push({ product_id: params[:product_id], quantity: 1 })
             customer_info = Hash.new
             @card_infos = { card_items: card_items, customer_info: customer_info }
             session[:SHOPPING_CARD_SESSION_NAME] = @card_infos
+          end
           redirect_to cards_path
         else
           card_items = @card_infos[:card_items]

venshop_app/app/controllers/product_categories_controller.rb

@@ -2,14 +2,14 @@ class ProductCategoriesController < ApplicationController
   add_breadcrumb "Products", :products_path
 
   def show
+    if ProductCategory.exists?(params[:id])
     	term = ProductCategory.find(params[:id])
-  	if term.nil?
-  		@items = Array.new
-  		@title = ''
-  	else
   		@items = Product.get_products_by_category(product_category_id: params[:id], page: params[:page], limit: 24)
   		@title = term.name
       add_breadcrumb term.name, product_category_path(term)
+    else
+      flash[:error] = "Invalid product category!"
+      redirect_to products_path
     end
   end
 end

venshop_app/app/controllers/products_controller.rb

@@ -7,6 +7,7 @@ class ProductsController < ApplicationController
   end
 
   def show
+    begin
       @product = Product.find(params[:id])
       if !@product.status
         user = current_user
@@ -20,6 +21,10 @@ class ProductsController < ApplicationController
         add_breadcrumb @product.name, product_path(@product)
       end
       @other_products = Product.get_other_products(@product.id, product_category_id: @product.product_category_id, limit: 20)
+    rescue
+      flash[:error] = "Invalid product!"
+      redirect_to products_path
+    end
   end
 
   def new

venshop_app/app/controllers/users_controller.rb

@@ -13,7 +13,12 @@ class UsersController < ApplicationController
   end
 
   def show
+    if User.exists?(params[:id])
       @user = User.find(params[:id])
+    else
+      flash[:error] = "Invalid user!"
+      redirect_to root_path
+    end
   end
 
   def create

venshop_app/app/views/default_pages/home.html.erb

@@ -3,6 +3,7 @@
           <h2 class="sprite-2">
             Recommended Items<span class="sprite-2"></span>
           </h2>
+          <div id="block-message-visible" class="hidden"></div>
           <%= render 'shared/grid', items: @recommed_items %>
           <div class="clearfix"></div>
         </div>

venshop_app/app/views/products/index.html.erb

@@ -3,6 +3,7 @@
   <h2 class="sprite-2">
     Products<span class="sprite-2"></span>
   </h2>
+  <div id="block-message-visible" class="hidden"></div>
   <%= render 'shared/grid', items: @products %>
 
   <%= will_paginate @products, renderer: BootstrapPagination::Rails %>

venshop_app/app/views/products/show.html.erb

@@ -2,6 +2,7 @@
 <div class="body-box">
   <h2 class="sprite-2"><%= @product.name %><span class="sprite-2"></span></h2>
   <div class="text-justify product-detail">
+    <div id="block-message-visible" class="hidden"></div>
     <% if !@product.status %>
     <div class="alert alert-danger">
       <p class="text-center">This product is only visible to you.</p>