<\/embed><\/object>View is the Part of the MVC architecture which renders or parses the generated html and javascript code to the Browser. Compared to Model and Controller files(.rb) which are Classes and have only Ruby code in them, View files(.rhtml or .rjs) have html and\/or javascript code and have Ruby code embedded in them between <% …some ruby code…%><\/p>\n
The author shows and explains a simple Recipe list which has Recipes with add\/edit\/delete and search functionalities. He goes through the Controller code which will in-turn parse to View to render html to browser. Name of the Controller file and Controller class are related and is generated by Rails. In this example, the controller’s class name is RecipeController and the controller file name is recipe_controller.rb , which is as follows<\/p>\n
[sourcecode language=’ruby’]
def add_recipe
def delete_the_recipe
def edit_recipe
def save_recipe
end
View Part 2<\/h2>\n <\/embed><\/object><\/p>\nSummary:<\/p>\n
From the previous Video, we look at list.rhtml. It is called by ‘list’ method\/function in RecipeController class. The beauty of Rails is that you dont have to specify the name of the View file, its convention is to have the Controller class name itself. In this case it is list.rhtml whose content is as follows<\/p>\n
[sourcecode language=’html’]
Recipe List <\/title><br \/>\n<\/head><br \/>\n<body><\/p>\n<p style=\"color: green\"><%= flash[:notice] %> <\/p>\n<p><%= render(:partial => ‘the_list”)%><\/p>\n<p><\/body><br \/>\n<\/html><br \/>\n[\/sourcecode]<\/p>\n<p>In the above snippet of code, the major part is normal html. The Ruby code is put between <% …some code … %> if its not printing anything on the browser . If you are outputting or printing something, we use <%= ..some code.. %>.<\/p>\n<p>The line <%= render(:partial => “the_list”) %> renders another view, in this case its a partial view. The partial views can only be called from main views and hence can be used repeatedly at many places. The partial view file is named _the_list.rhtml . There is an underscore before the file name to distinguish it as a partial view. The contents of ‘_the_list.rhtml’ file is as follows<\/p>\n<p>[sourcecode language=’html’]<\/p>\n<table border=\"0\"><% for a_recipe in @all_recipes%> <!-- @all_recipes was the instance variable from RecipeController. It is taken in a loop where each iteration variable is 'a_recipe' --><\/p>\n<tbody>\n<tr>\n<td><%=link_to \"View Recipe\", :action=> ‘view’, :id=> a_recipe %><\/td>\n<td><%=a_recipe.title %><\/td>\n<td><%=a_recipe.description %><\/td>\n<td><%=link_to \"Edit\", :action=> ‘edit_recipe’, :id=> a_recipe %><\/td>\n<td><%=link_to \"Delete\", :action=> ‘delete_the_recipe’, :id=> a_recipe %><\/td>\n<\/tr>\n<p><% end%> <!-- for loop end --><\/p>\n<\/tbody>\n<\/table>\n<hr \/>\n<p><%= render(:partial => “search_form”)%><br \/>\n<%= link_to \"Add New Recipe\", :action => ‘show_add_recipe’ %><br \/>\n[\/sourcecode]<\/p>\n<p>In the above snippet of code,<\/p>\n<ul>\n<li> @all_recipes which is parsed from RecipeController is taken on a Loop.<\/li>\n<li> On every iteration, variable ‘a_recipe’ is rendered in a new table-row.<\/li>\n<li> To print the title of a recipe, we use a_recipe.title and similarly for description, we use a_recipe.description.<\/li>\n<li> In <%= link_to ‘View Recipe”, action=> ‘view’, :id=> a_recipe %> , link_to is a Ruby function which builds an anchor or link with text “View Recipe” and clicking on it will trigger ‘view’ function in RecipeController and parses ‘id’ as an argument.<\/li>\n<li> <%= render(:partial => “search_form”) %> will render “_the_search_form.rhtml” file<\/li>\n<\/ul>\n<hr style=\"display: block;\" \/>\n<h2>Controller<\/h2>\n<p><object classid=\"clsid:d27cdb6e-ae6d-11cf-96b8-444553540000\" width=\"425\" height=\"344\" codebase=\"http:\/\/download.macromedia.com\/pub\/shockwave\/cabs\/flash\/swflash.cab#version=6,0,40,0\"><param name=\"src\" value=\"http:\/\/www.youtube.com\/v\/92eyuiXq194&hl=en\" \/><embed type=\"application\/x-shockwave-flash\" width=\"425\" height=\"344\" src=\"http:\/\/www.youtube.com\/v\/92eyuiXq194&hl=en\"><\/embed><\/object><\/p>\n<p>Summary:<\/p>\n<p>Controller can be thought of a co-ordinator between a model and a view. A controller is usually called by a URL from the web-browser. Say there is a URL request of http:\/\/0.0.0.0:3000\/recipe\/list , it directly goes to controller recipe, whose filename is recipe_controller.rb and whose class name is RecipeController. All these would seem a bit confusing at first, but once you are familiar with the conventions, it would be a cake walk in future. The next part of the url after the controller name is ‘list’, which is the function name inside ‘recipe’ controller.<\/p>\n<p>Lets explore ‘recipe_controller.rb’ file<\/p>\n<p>[sourcecode language=’ruby’]<br \/>\nclass RecipeController < ApplicationController # Subclass of ApplicationController, Class is i\n\ndef list #function or method. An important convention is that it parses a view file by the same name. i.e list.rhtml and is not explicitly mentioned\n@all_recipes = Recipe.find(:all) #It finds all the recipes and stores in instance variable 'all_recipes'\nend\n\ndef view\n@a_recipe = Recipe.find(params[:id]) #it finds a recipe with a given id\n@all_recipes = Recipe.find(:all) #It finds all the recipes\nend\n\ndef show_add_recipe\nend\n\ndef search\ntitle = \"%\" + @params[:title] + \"%\"\n@all_recipes = Recipe.find(:all, :condtions=>[“title like ?”, title])<br \/>\nend<\/p>\n<p>def add_recipe<br \/>\n@a_recipe = Recipe.new(params[:new_recipe])<br \/>\n@a_recipe.save<br \/>\nredirect_to :action => ‘list’<br \/>\nend<\/p>\n<p>def delete_the_recipe<br \/>\nRecipe.find(params[:id]).destroy<br \/>\nredirect_to :action => ‘list’<br \/>\nend<\/p>\n<p>def edit_recipe<br \/>\n@recipe_to_edit = Recipe.find(params[:id])<br \/>\nend<\/p>\n<p>def save_recipe<br \/>\n@recipe_to_update = Recipe.find(@params[:a_recipe_id])<br \/>\n@recipe_to_update.update_attributes(@params[:recipe_to_edit])<br \/>\nredirect_to :action => ‘list’<br \/>\nend<\/p>\n<p>end<br \/>\n[\/sourcecode]<\/p>\n<p>In the following snippet of code, RecipeController class is made a sub-class of ApplicationController, meaning it derives all the properties of ApplicationController (Inheritance property of OOP). The class should always be terminated by ‘end’<br \/>\n[sourcecode language=’ruby’]<br \/>\nclass RecipeController < ApplicationController\n.....\n.....\nend\n[\/sourcecode]\n\nIn the following snippet of code, 'list' is a function\/method. It is defined by keyword 'def' followed by its name. It is terminated by 'end'. Whatever is in between them is executed upon calling the function. In this case, there is a ActiveRecord Model named 'Recipe'. Recipe.find(:all) will interact with recipe corresponding table in database and get all the rows. The relational data from database is converted into Object by ActiveRecord and it is assigned to instance variable @all_recipes in the form of an array. Once this is done, the function will then call the view file with the same name as its, and parse the instance variables. In this case, it would be 'list.rhtml' as we had covered in the previous video summary.\n[sourcecode language='ruby']\ndef list\n@all_recipes = Recipe.find(:all)\nend\n[\/sourcecode]\n\nSince a Controller is the co-ordinator for Views and Models, if we have less code in View and more in Controller, it would become easy to maintain and update the code.\n\n\n\n<hr style=\"display: block;\" \/>Disclaimer: The Screencasts are not recorded by me. I have just embedded them from Youtube. The original Videos area a part of <a href=\"http:\/\/www.vtc.com\/products\/ruby-on-rails-tutorials.htm\" target=\"_blank\">Virtual Training Company<\/a>, who give Online Training and the author for Ruby on Rails Series is Mr. Al Anderson. If you are benefited from these, you may register there by paying certain amount or order a CD from them.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In this post, the following Concepts are explained Web Applications and Rails What Rails can Do Where Rails Came From Rails Philosophies More Rails Philosophies MVC Model View Part 1 View Part 2 Controller Web Applications and Rails Summary: Basic … <a href=\"https:\/\/www.ar-cad.com\/smallguru\/2008\/06\/rails-video-tutorial-2\/\">Continue reading <span class=\"meta-nav\">→<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","footnotes":""},"categories":[7],"tags":[28,30],"class_list":["post-14","post","type-post","status-publish","format-standard","hentry","category-tutorials","tag-video-tutorials","tag-web20"],"_links":{"self":[{"href":"https:\/\/www.ar-cad.com\/smallguru\/wp-json\/wp\/v2\/posts\/14","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ar-cad.com\/smallguru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ar-cad.com\/smallguru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ar-cad.com\/smallguru\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ar-cad.com\/smallguru\/wp-json\/wp\/v2\/comments?post=14"}],"version-history":[{"count":0,"href":"https:\/\/www.ar-cad.com\/smallguru\/wp-json\/wp\/v2\/posts\/14\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.ar-cad.com\/smallguru\/wp-json\/wp\/v2\/media?parent=14"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ar-cad.com\/smallguru\/wp-json\/wp\/v2\/categories?post=14"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ar-cad.com\/smallguru\/wp-json\/wp\/v2\/tags?post=14"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}