Rolling with Rails 2.0 - The First Full Tutorial - Part 1
/ 12.Dec.2007 at 01:15pm
for brazilians: click here.
I am very happy to see that my Rails 2.0 Screencast was very well received. More than 1,500 unique visitors watched it. The idea was to showcase Rails 2.0 very fast, showing what is possible to do in less than 30 min.
Now, I will break that video down into its main pieces and create the very first full featured step-by-step tutorial around Rails 2.0.
Like any other tutorial, it doesn’t cover 100% of Rails 2.0, just some of its main features packed in a cohesive application. I recommend checking out Peepcode’s Rails2 PDF and Ryan Bates Railscasts.com for more details.
This is a 2 part tutorial, for Part 2, click here. And for the full source codes of this tutorial, get it here.
Let’s get started!
Recognizing the Environment
This tutorial is geared towards those who already have some knowledge of Rails 1.2. Please refer to the many great Rails tutorials around 1.2 available in the Internet world-wide.
The first think you have to do is update your gems:
sudo gem install rails --include-dependencies
You may probably need to update RubyGems as well:
sudo gem update --system
First things first. Let’s create a new Rails application:
rails blog
This will create our usual Rails folder structure. The first thing to notice is the environment: we now have this main structure:
- config/environment.rb
- config/initializers/inflections.rb
- config/initializers/mime_types.rb
Everything that inside the config/initializers folder is loaded at the same time the original environment.rb is, and that’s because when you’re using several different plugins and gems in your project, the environment.rb file tends to become cluttered and difficult to maintain. Now we have an easy way to modularize our configuration.
Database
The second thing that we have to do is configure our databases. This is done the same way as before at config/database.yml:
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development: adapter: mysql encoding: utf8 database: blog_development username: root password: root socket: /opt/local/var/run/mysql5/mysqld.sock test: adapter: mysql encoding: utf8 database: blog_test username: root password: root socket: /opt/local/var/run/mysql5/mysqld.sock production: adapter: mysql encoding: utf8 database: blog_production username: root password: root socket: /opt/local/var/run/mysql5/mysqld.sock |
Notice that now you have a ‘encoding’ options that’s set to UTF8 by default. The Rails app itself loads up with KCODE = true by default as well, meaning that it silently starts with Unicode support already, which is great. But that ‘encoding’ configuration has a new usage as well: everytime Rails connects to the database it will tell it to use this ‘encoding’ setting. Like issuing a ‘SET NAMES UTF8’.
One trick that we can do to DRY up our database.yml is this:
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defaults: &defaults
adapter: mysql
encoding: utf8
username: root
password: root
socket: /opt/local/var/run/mysql5/mysqld.sock
development:
database: blog_development
<<: *defaults
test:
database: blog_test
<<: *defaults
production:
database: blog_production
<<: *defaults
|
Much better. We have new Rake tasks as well. And some of them are related to the database:
| db:charset | Retrieves the charset for the current environment’s database |
| db:collation | Retrieves the collation for the current environment’s database |
| db:create | Create the database defined in config/database.yml for the current RAILS_ENV |
| db:create:all | Create all the local databases defined in config/database.yml |
| db:drop | Drops the database for the current RAILS_ENV |
| db:drop:all | Drops all the local databases defined in config/database.yml |
| db:reset | Drops and recreates the database from db/schema.rb for the current environment. |
| db:rollback | Rolls the schema back to the previous version. Specify the number of steps with STEP=n |
| db:version | Retrieves the current schema version number |
We have a far better database administration support. In the older Rails now we would log into our databases admin consoles and create the database manually. Now, we can do simply:
rake db:create:all
If we want to start from scratch, we can do db:drop:all. And in the middle of development we can do db:rollback to undo the latest migration file.
Sexyness
With database set and ready to go, we can create our first Resource. Remember now that Rails 2.0 is RESTful by default (for brazilians: I am writing a separated RESTful Tutorial as well).
./script/generate scaffold Post title:string body:text
The only difference here is that the ‘scaffold’ behaves like the ‘scaffold_resource’ we had before, and the old non-RESTful scaffold is gone. You also don’t have the ActionController class method ‘scaffold’ that dynamically populated your empty controller with default actions. So, everything scaffold we do is RESTful now.
It will create the usual suspects: Controller, Helper, Model, Migration, Unit Test, Functional Test.
The main difference is in the Migration file:
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# db/migrate/001_create_posts.rb class CreatePosts < ActiveRecord::Migration def self.up create_table :posts do |t| t.string :title t.text :body t.timestamps end end def self.down drop_table :posts end end |
This is called Sexy Migrations, first devised by “Err the Blog” as a plugin and it found its way into the Core. The best way to understand the different is to take a look at what this migration would look like in Rails 1.2:
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class CreatePosts < ActiveRecord::Migration def self.up create_table :posts do |t| t.column :title, :string t.column :body, :text t.column :created_at, :datetime t.column :updated_at, :datetime end end def self.down drop_table :posts end end |
It gets rid of the ‘t.column’ repetition and now uses the format ‘t.column_type’ and the automatic datetime columns are concentrated in a single ‘t.timestamps’ statement. It doesn’t chance any behavior, just makes the code ‘sexier’.
Now, we run the migration like before:
rake db:migrate
In the old days, if I wanted to rollback a migration change I had to do:
rake db:migrate VERSION=xxx
Where ‘xxx’ is the version where we wanted to go back to. Now we can simply issue:
rake db:rollback
Much nicer and more elegant, that’s for sure. All set, we can now start our server as before and take a look at the generated pages:
./script/server
It will load either Mongrel, Webrick or Lightpd at port 3000. We have the same root page as before, showing up the index.html page. One tidbit that I didn’t show at the screencast is this:
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# config/routes.rb ActionController::Routing::Routes.draw do |map| map.root :controller => 'posts' map.resources :posts end |
There is a new ‘map.root’ statement which have the same effect as “map.connect ’’, :controller => ‘posts’. Just a small nicety that doesn’t do anything big but tries to make the routes file feel more polished. Once you set that, don’t forget to delete the public/index.html file. Not the root URL will always be pointed to the Posts controller.
As you can see, everything feels the same as before. All the scaffold templates are the same. You can browse around, create new rows and so on.
Nested Routes
So, let’s create a companion Comment resource for the Post. That should complete our Blog’s resources:
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./script/generate scaffold Comment post:references body:text rake db:migrate |
Same thing here: scaffold the resource, configure the column names and datatypes in the command line and the migration file will be already set. Notice another small addition: the keyword ‘references’. As my friend Arthur reminded me, this makes migrations even sexier. To compare, this is the old way of doing the same thing:
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./script/generate scaffold Comment post_id:integer body:text |
Foreign keys are just implementation details that don’t matter. Take a look at the new migration file for this:
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def self.up create_table :comments do |t| t.references :post t.text :body t.timestamps end end |
Take a look here for details on this new ‘references’ keyword. So, running db:migrate creates the table in the database. Then, we configure the ActiveRecord models so they relate to each other like this:
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# app/models/post.rb class Post < ActiveRecord::Base has_many :comments end # app/models/comment.rb class Comment < ActiveRecord::Base belongs_to :post end |
Ok, nothing new here, we already know how to work with ActiveRecord associations. But we are also working with RESTful resources. In the new Rails way, we would like to have URLs like these:
http://localhost:3000/posts/1/comments
http://localhost:3000/posts/1/comments/new
http://localhost:3000/posts/1/comments/3
Meaning: ‘grab the comments from this particular post’ The scaffold generator only made it ready to do URLs like these:
http://localhost:3000/posts/1
http://localhost:3000/comments/new
http://localhost:3000/comments/3
That’s because in the config/routes.rb we have:
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# config/routes.rb ActionController::Routing::Routes.draw do |map| map.resources :comments map.root :controller => 'posts' map.resources :posts end |
Let’s tweak it a bit. Just like in the models, we can create what’s called a Nested Route:
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# config/routes.rb ActionController::Routing::Routes.draw do |map| map.root :controller => 'posts' map.resources :posts, :has_many => :comments end |
Just like that! Now we can do the nested URLs as showed above. The first thing to understand is that when I type in this URL:
http://localhost:3000/posts/1/comments
Rails will parse it like this:
- Load the CommentsController
- Set params[:post_id] = 1
- In this case, call the ‘index’ action
We have to make the CommentsController prepared to be nested. So that’s what we are going to change:
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class CommentsController < ApplicationController before_filter :load_post ... def load_post @post = Post.find(params[:post_id]) end end |
This makes the @post already set for all the actions within the Comments controller. Now we have to make these changes:
| Before | After |
| Comment.find | @post.comments.find |
| Comment.new | @post.comments.build |
| redirect_to(@comment) | redirect_to([@post, @comment]) |
| redirect_to(comments_url) | redirect_to(post_comments_url(@post)) |
That should make the Comments controller ready. Now let’s change the 4 views at app/views/comments. If you open up either new.html.erb or edit.html.erb you will notice the following new feature:
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# new edit.html.erb and new.html.erb form_for(@comment) do |f| ... end |
That’s the new way of doing this old statement in Rails 1.2:
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# old new.rhtml form_for(:comment, :url => comments_url) do |f| ... end |
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# old edit.rhtml form_for(:comment, :url => comment_url(@comment), :html => { :method => :put }) do |f| ... end |
Notice how the same form_for statement suits both ‘new’ and ‘edit’ situations. That’s because Rails can infer what to do based on the Class name of the @comment model instance. But now, for the Nested Route, comments is dependent on the Post, so that’s what we have to do:
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# new edit.html.erb and new.html.erb form_for([@post, @comment]) do |f| ... end |
Rails will try to be smart enough to understand that this array represents a Nested Route, will check routes.rb and figure out and this is the post_comment_url(@post, @comment) named route.
Let’s explain named routes first. When we set a Resource Route in the routes.rb. We gain these named routes:
| route | HTTP verb | Controller Action |
| comments | GET | index |
| comments | POST | create |
| comment(:id) | GET | show |
| comment(:id) | PUT | update |
| comment(:id) | DELETE | destroy |
| new_comment | GET | new |
| edit_comment(:id) | GET | edit |
“7 Actions to Rule them all …” :-)
You can suffix them with both ‘path’ or ‘url’. The difference being:
| comments_url | http://localhost:3000/comments |
| comments_path | /comments |
Finally, you can prefix them with ‘formatted’, giving you:
| formatted_comments_url(:atom) | http://localhost:3000/comments.atom |
| formatted_comment_path(@comment, :atom) | /comments/1.atom |
Now, as Comments is nested within Post, we are obligated to add the prefix ‘post’. In Rails 1.2 this prefix was optional, it was able to tell the difference by the number or parameters passed to the named route helper, but this could lead to many ambiguities so it is now mandatory to have the prefix, like this:
| route | HTTP verb | URL |
| post_comments(@post) | GET | /posts/:post_id/comments |
| post_comments(@post) | POST | /posts/:post_id/comments |
| post_comment(@post, :id) | GET | /posts/:post_id/comments/:id |
| post_comment(@post, :id) | PUT | /posts/:post_id/comments/:id |
| post_comment(@post, :id) | DELETE | /posts/:post_id/comments/:id |
| new_post_comment(@post) | GET | /posts/:post_id/comments/new |
| edit_post_comment(@post, :id) | GET | /posts/:post_id/comments/edit |
So, to summarize, we have to make the Comments views to behave like they are nested within a Post. So we have to change the named routes within from the default scaffold generated code to the nested form:
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<!-- app/views/comments/_comment.html.erb --> <% form_for([@post, @comment]) do |f| %> <p> <b>Body</b><br /> <%= f.text_area :body %> </p> <p> <%= f.submit button_name %> </p> <% end %> |
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<!-- app/views/comments/edit.html.erb --> <h1>Editing comment</h1> <%= error_messages_for :comment %> <%= render :partial => @comment, :locals => { :button_name => "Update"} %> <%= link_to 'Show', [@post, @comment] %> | <%= link_to 'Back', post_comments_path(@post) %> |
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<!-- app/views/comments/new.html.erb --> <h1>New comment</h1> <%= error_messages_for :comment %> <%= render :partial => @comment, :locals => { :button_name => "Create"} %> <%= link_to 'Back', post_comments_path(@post) %> |
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<!-- app/views/comments/show.html.erb --> <p> <b>Body:</b> <%=h @comment.body %> </p> <%= link_to 'Edit', [:edit, @post, @comment] %> | <%= link_to 'Back', post_comments_path(@post) %> |
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<!-- app/views/comments/index.html.erb --> <h1>Listing comments</h1> <table> <tr> <th>Post</th> <th>Body</th> </tr> <% for comment in @comments %> <tr> <td><%=h comment.post_id %></td> <td><%=h comment.body %></td> <td><%= link_to 'Show', [@post, comment] %></td> <td><%= link_to 'Edit', [:edit, @post, comment] %></td> <td><%= link_to 'Destroy', [@post, comment], :confirm => 'Are you sure?', :method => :delete %></td> </tr> <% end %> </table> <br /> <%= link_to 'New comment', new_post_comment_path(@post) %> |
Some remarks:
- Notice that I created a partial to DRY up the new and edit forms. But pay attention that instead of :partial => ‘comment’, I did :partial => @comment. Then again it can infer the name of partial from the class name. If we passed a collection it would do the equivalent of the old ’:partial, :collection’ statement.
- I can use both post_comment_path(@post, @comment), or simply [@post, @comment]
- Pay close attention to not forget any named route behind.
Finally, it would be good to link the comments list to the post view. So let’s do it:
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<!-- app/views/posts/show.html.erb --> <%= link_to 'Comments', post_comments_path(@post) %> <%= link_to 'Edit', edit_post_path(@post) %> | <%= link_to 'Back', posts_path %> |
So, I just added a link there. Let’s see how it looks like:
Completing the Views
Ok, looks good, but that’s not how a Blog should behave! The Post’s show view should already have the Comments listing and New Comment Form as well! So let’s make some small adaptations. There’s nothing new here, just traditional Rails. Let’s start at the view:
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<!-- app/views/posts/show.html.erb --> <p> <b>Title:</b> <%=h @post.title %> </p> <p> <b>Body:</b> <%=h @post.body %> </p> <!-- #1 --> <% unless @post.comments.empty? %> <h3>Comments</h3> <% @post.comments.each do |comment| %> <p><%= h comment.body %></p> <% end %> <% end %> <!-- #2 --> <h3>New Comment</h3> <%= render :partial => @comment = Comment.new, :locals => { :button_name => 'Create'}%> <%= link_to 'Comments', post_comments_path(@post) %> <%= link_to 'Edit', edit_post_path(@post) %> | <%= link_to 'Back', posts_path %> |
More remarks
- There is nothing new in the iterator, just listing all comments
- Again, we pass in the @comment variable to the partial statement
One final adjustment: whenever we create a new post, we would like to return to the same Posts’ show view, so we change the CommentsController to behave like this:
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# app/controllers/comments_controller.rb # old redirect: redirect_to([@post, @comment]) # new redirect: redirect_to(@post) |
Namespaced Routes
Ok, now we have a bare bone mini-blog that kind of mimics the classic blog from the ‘15 minute’ screencast David did in 2005. Now let’s go one step further: Posts should not be publicly available to anyone to edit, we need an Administration section in our website. Let’s create a new controller for that:
./script/generate controller Admin::Posts
Rails 2.0 now supports namespaces. This will create a sub-directory called app/controllers/admin.
What we want to do is:
- Create a new routes
- Copy all actions from the old Posts controller to the new Admin::Posts
- Copy the old posts views to app/views/admin* Leave the old Posts controller with only the ‘index’ and ‘show’ actions, this means deleting the new and edit views as well
- Adapt the actions and views we just copied so it understands it is within the admin controller
First things first, let’s edit config/routes.rb again:
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map.namespace :admin do |admin| admin.resources :posts end |
In practice this means that we now have names routes for Posts with the prefix ‘admin’. This will disambiguate the old posts routes from the newest admin posts routes, like this:
| posts_path | /posts |
| post_path(@post) | /posts/:post_id |
| admin_posts_path | /admin/posts |
| admin_post_path(@post) | /admin/posts/:post_id |
Now let’s copy the actions from the old Post controller and adapt the routes to fit the new namespace:
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# app/controllers/admin/posts_controller.rb ... def create # old: format.html { redirect_to(@post) } # new: format.html { redirect_to([:admin, @post]) } end def update # old: format.html { redirect_to(@post) } # new: format.html { redirect_to([:admin, @post]) } end def destroy # old: format.html { redirect_to(posts_url) } # new: format.html { redirect_to(admin_posts_url) } end ... |
Don’t forget to delete all the methods from the app/controllers/posts_controller.rb, leaving just the ‘index’ and ‘show’ methods.
Now, let’s copy the views (assuming your shell is already in the project’s root folder):
cp app/views/posts/*.erb app/views/admin/posts
rm app/views/posts/new.html.erb
rm app/views/posts/edit.html.erb
Now, let’s edit the views from app/views/admin/posts:
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<!-- app/views/admin/posts/edit.html.erb --> <h1>Editing post</h1> <%= error_messages_for :post %> <% form_for([:admin, @post]) do |f| %> ... <% end %> <%= link_to 'Show', [:admin, @post] %> | <%= link_to 'Back', admin_posts_path %> |
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<!-- app/views/admin/posts/new.html.erb --> <h1>New post</h1> <%= error_messages_for :post %> <% form_for([:admin, @post]) do |f| %> ... <% end %> <%= link_to 'Back', admin_posts_path %> |
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<!-- app/views/admin/posts/show.html.erb --> <p> <b>Title:</b> <%=h @post.title %> </p> <p> <b>Body:</b> <%=h @post.body %> </p> <%= link_to 'Edit', edit_admin_post_path(@post) %> | <%= link_to 'Back', admin_posts_path %> |
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<!-- app/views/admin/posts/index.html.erb --> ... <% for post in @posts %> <tr> <td><%=h post.title %></td> <td><%=h post.body %></td> <td><%= link_to 'Show', [:admin, post] %></td> <td><%= link_to 'Edit', edit_admin_post_path(post) %></td> <td><%= link_to 'Destroy', [:admin, post], :confirm => 'Are you sure?', :method => :delete %></td> </tr> <% end %> </table> <br /> <%= link_to 'New post', new_admin_post_path %> |
Almost done: if you test http://localhost:3000/admin/posts it should work properly now. But, it will look ugly, and that’s because we don’t have a global app layout. When we did the first scaffolds, Rails generated specific layouts for Post and Comment alone. So let’s delete them and create one that’s generic:
cp app/views/layouts/posts.html.erb \
app/views/layouts/application.html.erb
rm app/views/layouts/posts.html.erb
rm app/views/layouts/comments.html.erb
Then let’s just change the title of it:
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<!-- app/views/layouts/application.html.erb --> ... <title>My Great Blog</title> ... |
It only remain the old ‘index’ and ‘show’ pages from the previous Posts controllers. They still have links to the methods we deleted, so let’s rip them off from those links:
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<!-- app/views/posts/index.html.erb --> <h1>My Great Blog</h1> <table> <tr> <th>Title</th> <th>Body</th> </tr> <% for post in @posts %> <tr> <td><%=h post.title %></td> <td><%=h post.body %></td> <td><%= link_to 'Show', post %></td> </tr> <% end %> </table> |
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<!-- app/views/posts/show.html.erb --> <p> <b>Title:</b> <%=h @post.title %> </p> <p> <b>Body:</b> <%=h @post.body %> </p> <% unless @post.comments.empty? %> <h3>Comments</h3> <% @post.comments.each do |comment| %> <p><%= h comment.body %></p> <% end %> <% end %> <h3>New Comment</h3> <%= render :partial => @comment = Comment.new, :locals => { :button_name => 'Create'}%> <%= link_to 'Back', posts_path %> |
We can test everything from the browser, go in http://localhost:3000/admin/posts and see that everything is working properly now. But, we still have one thing missing: an administration section should not be publicly available. Right now you can just jump in and edit everything. We need authentication.
HTTP Basic Authentication
There are several ways of implementing authentication and authorization. One plugin that’s widely used for this is restful_authentication.
But, we don’t want to make anything fancy here. And for that Rails 2.0 gives us a great way of authenticating. The idea is: let’s use what HTTP already gives us: HTTP Basic Authentication. The drawback being: you will definitely want to use SSL when going into production. But, of course, you would do it anyway. HTML Form authentication is not protected without SSL either.
So, let’s edit our Admin::Posts controller to add authentication:
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# app/controllers/admin/posts.rb class Admin::PostsController < ApplicationController before_filter :authenticate ... def authenticate authenticate_or_request_with_http_basic do |name, pass| #User.authenticate(name, pass) name == 'akita' && pass == 'akita' end end end |
You already know what ‘before_filter’ does: it runs the configured method before any action in the controller. If you set it in the ApplicationController class, then it runs before any action from any other controller. But we only want to protect Admin::Posts here.
Then, we implement this method and the secret sauce is the ‘authenticate_or_request_with_http_basic’ method that let’s us configure a block. It gives us the username and password that the user typed in the browser. We would usually have a User model of some kind to authenticate this data, but for our very very simple example I am hard coding the checking, but you get the idea.
119 Comments
Nice tutorial, Akita! :)
In Rails 2.0 you can use:
./script/generate scaffold Comment post:references body:text
I think it’s even more more sexy!
In Rails 1.2 you’d write:
create_table :taggings do |t|
t.integer :tag_id, :tagger_id, :taggable_id
t.string :tagger_type
t.string :taggable_type, :default => ‘Photo’
end
Now, in Rails 2.0 you can write:
create_table :taggings do |t|
t.references :tag
t.references :tagger, :polymorphic => true
t.references :taggable, :polymorphic => { :default => ‘Photo’ }
end
And t.belongs_to is an alias for t.references
More about that in: http://dev.rubyonrails.org/changeset/7973
arthurgeek / 12.Dec.2007 at 03:43pm
Amazing Akita, always writing good materials ;-)
Cheers,
paulo cassiano / 12.Dec.2007 at 05:42pm
Akita. O que é prioritário atualmente pra você? Lutar pela disseminação do Rails para Brasileiros?
eraldo / 12.Dec.2007 at 07:08pm
Thanks so much for the video and these great tutorials. I just started a new project last night and your tutorials have helped me solve some problems, and do things better.
Keep up the great work!
jim / 12.Dec.2007 at 09:25pm
Eraldo, minha prioridade é: trabalhar com o que gosto e me divertir no caminho. Tudo que vier junto com isso é lucro ;-)
akitaonrails / 12.Dec.2007 at 11:08pm
Arthur, hey, great tip. I updated the post to add this information.
BTW, I also updated Part 2 because I forgot to mention Cookie Session Store.
akitaonrails / 13.Dec.2007 at 08:46am
Rapaz,
Formatado assim tinha ficado mais fácil de eu gerar o PDF.
Vou gerar novamente depois usando as formatações do teu blog. Acho que fica mais bacana. Mandei pra ti no teu e-mail agora pouco.
Abraço!
davis / 13.Dec.2007 at 02:47pm
Fabio,
Thanks for helping get us up to speed with the great tutorials. We look forward to even more.
Rob
robert dempsey / 13.Dec.2007 at 04:38pm
When I try to go here
http://localhost:3000/posts/1/comments
I get
undefined method `comments’ for #<post:0x272e370>
What am I doing wrong?
Sorry, I’m a noob to rails
rob / 13.Dec.2007 at 05:59pm
Great article! Just a note for those using has_one associations:
Say you have ‘idea’ and ‘idea_response’ resources and each Idea will have at most one IdeaResponse. Instead of using ’@idea_response = @idea.build(params[:idea_response])’, you need to use ’@idea_response = @idea.build_idea_response(params[:idea_response])’. Notice that the function call to ‘build’ needs to be dynamically named to the nested resource (‘build’ becomes ‘build_idea_response’). I spent the whole day figuring this one out, and I hope it helps someone out there.
matt darby / 13.Dec.2007 at 07:20pm
A minor typo:
redirect_to(@comment) should be changed to read: redirect_to(@post, @comment) not redirect_to(post, @comment)
btw how do you get your ruby code nicely formatted for insertion into a blog?
~j / 14.Dec.2007 at 03:25pm
Thank you for the tutorial. Please post more.
ole / 14.Dec.2007 at 03:46pm
Hi,
Thanks for the nice and very useful tutorial. I am new to rails and couldn’t follow everything at once. If possible, can you please share the code.
thanks, Kris
kris / 15.Dec.2007 at 06:52am
Thanks for the great writeup! Rails 2.0 is looking pretty spiffy. Now if only I had the time to fully update my old 1.2 app. . .
-dath
dath / 17.Dec.2007 at 02:43am
Fábio, muito bom material, mas eu peço por favor, quando fizer a versão em português, use outro exemplo que não seja um blog, pois o Rails tá com cara de blog designer e esses termos “tag” “tagger” “taggable” parecem tudo a mesma coisa.. :)
paulo larini / 18.Dec.2007 at 08:22am
One extra gotcha I found was if you are running rails 2.0.2 it will default on a Mac to SqlLite3, to enable MySQL you need to use rails -d mysql blog rather than rails blog
david johnson / 18.Dec.2007 at 03:16pm
One extra thing, if you change the generate for comment to references, then you need to use post_id rather than post in the comments views otherwise you get a cryptic number rather than the post id
david johnson / 18.Dec.2007 at 04:26pm
I find that using that DRY database.yml I can’t actually generate the DB?
max russell / 20.Dec.2007 at 02:52pm
Thank you, for this great tutorial. It covers some neat changes and introduces REST really cool!
johannes / 20.Dec.2007 at 03:34pm
Thank you very much for this excellent introduction to Rails 2.0. I’m using this as a drop-in replacement for the not-yet-updated AWDWR. :-)
andreas / 21.Dec.2007 at 10:46am
Could you post the full, completed html.erb files?
max russell / 21.Dec.2007 at 11:27am
Please fix tutorial. Rob’s comment dated 13 Dec 17:59 has not been addressed as the same problem occurs for me.
Thanks and great post!
maxrcul / 28.Dec.2007 at 04:11am
rob and maxrcul, sorry for the delay, but it seems that you didn’t place this line in your app/models/post.rb file:
has_many :comments
akitaonrails / 28.Dec.2007 at 01:29pm
great stuff
wonderful to see a tutorial like this so soon after rails 2.0 came out.
the only slight wee bit of criticism would be the admin post controller part. I had to read it a few times to understand that you really do mean to copy ALL of the existing controller over, and then simply change the redirect links to the code you have written out. if you are in the mood to tweek, perhaps you can just cut and paste the controller in? either way, great stuff.
superbnerb / 30.Dec.2007 at 08:08pm
thank you so much akita for the time and efforts you put into the tuts!!!
bastien / 31.Dec.2007 at 06:52am
Hi there. Thank you so much for such a detailed tutorial. I would never have begun with Rails 2.0 this soon without it. I have “agile web dev” but the tutorials in it are now mostly broken.
Thanks to the others who left comments and corrected some typos and issues that had me scratching my head for some time!
You’ve done rally well showing how to have an admin section and basic authentication. Is someone able to tell me how to make a logout link for the admin section?
Many thanks, keep up the good work. Gabriel.
gabriel / 01.Jan.2008 at 11:16am
Nice tutorial
satish chauhan / 01.Jan.2008 at 11:54am
thank you for this great tutorial on Rails 2!
fernando correia / 01.Jan.2008 at 01:48pm
Hi Akita. Greetings from South Africa. Great tutorial. Your screencast was quite fast so I had to view it several times just to keep up. I have used your example to create my own project but I need to take it a step further. To use your post/comments example I would like to add an additional layer for example add a response to a specific comment(has_many => responses) so that you are able to create a response from the post/comments/show view. How would this affect the actions/nested routes in the responses controller – does it have to make reference to the comments controller only or should it also make reference to the posts controller? How would the additional method look in the responses controller i.e. load_response, @comments = Comments.find(params[:comments_id]) or should it be looking for the posts as well? Thanks in anticipation
archie / 01.Jan.2008 at 05:27pm
Your tutorial helps alot. I’m just starting Rails and almost every books in town uses rails 1.2. Its kinda difficult for me to test and develop an application using newer rails (2.0.2) when the available references uses 1.2. Thanks again Akita.
techtitan / 02.Jan.2008 at 08:29am
awesome!!
I’ve been googling for 2 days for nested routing at Rails2.0.
So far your article is the best I’ve ever seen about Rails2.0. THANKS!
jai-gouk / 04.Jan.2008 at 01:24am
OMG! I am still learning Rails myself, but this was the most fun I have learning anything. I did get those few hiccups when I did, but it felt good for me to figure out those for myself. Thanks for the great intro!
lockheartmac / 04.Jan.2008 at 04:33am
thanx for writing a nice tutorial on rails 2.0. willing to see more on this and also on Rspec.
hemantsonker / 04.Jan.2008 at 11:17am
thank you for this was a fantastic demo! i’ve begun writing a blog based on your code and it’s coming along.
one thing that’s really lacking in rails tutorials everywhere is persistence. i’d love to see you take this little blog application and run with it – with the ultimate goal of developing blog software that features user submitted comments, comment moderation, captcha, user authentication with rest, tags, and possibly cookied themes.
that would just about make my year, and here it is just starting! :)
cheers and thanks
seaofclouds / 05.Jan.2008 at 08:48am
First of all – thanks for this excellent tutorial. That would be a great start for a whole book I’d immediately purchase! Just one thing: it would be great to have a “print view”. Unfortunatly one can’t print your tutorial fine at the moment – neither with Firefox, nor with Internet Explorer.
martin / 05.Jan.2008 at 09:55pm
Hi,
Thanks for the great tutorial. Just got started on a new RESTful project and this one really helped out. Im trying to make my comments controller inside a subdirectory “module/comment_controller.rb”
In this case how can I modify routes.rb so that i can get /user/:id/comments as normal?
I cant seem to find any detailed tutorials on building apps with sub controllers.. maybe that can be your next one :)
ali / 07.Jan.2008 at 10:25am
thankx! good job!
bayer / 08.Jan.2008 at 10:32am
ótimo trabalho fábio, foi vc que fez o video tutorial do www.rubyonrails.com sobre blog, muito om os dois um complemta o outro. parabens
Um abraço.
pinhux / 09.Jan.2008 at 02:27am
redirect_to(post, @comment) There is one error. undefined `post’.
post must change to @post.
nome?name? medivh. / 09.Jan.2008 at 05:37am
Como fazer com algo do tipo: script/generate scaffold Model ‘admin/model’?
Obrigado
ratulo / 09.Jan.2008 at 10:25pm
Very good! Beginners need it _.
medivh / 11.Jan.2008 at 07:16am
I am getting a Segmentation Fault from Ruby when I attempt the “rake db:create:all” command.
Using rake 0.8.1, ActiveSupport 2.0.2, Ruby 1.8.6p111 on Windows Vista. Also mysql 5.1.22-rc.
Not really sure where to do from here. Anyone else having this issue?
jason collins / 11.Jan.2008 at 07:08pm
Great tutorial, thanks!
scarf*oo / 13.Jan.2008 at 11:33am
Why is it that the Rails community makes such a big deal about test driven development and yet every single tutorial (book or web) completely ignores testing or at best deals with it is an after-thought?
edward / 14.Jan.2008 at 06:42am
Great tutorial! I also was searching for a tutorial that covers 2.0. I’m just starting to learn Ruby and Rails and all tutorials and books are not up-to-date yet.
Great tutorial!
matthijs / 16.Jan.2008 at 07:49am
Great Tutorial, one quick correction however, near the start where you go through changing the CommentsController, the following says Before After redirect_to(@comment) redirect_to(post, @comment)
It doesn’t work for me unless i do
Before After redirect_to(@comment) redirect_to(@post, @comment)
tom / 16.Jan.2008 at 11:59am
o tutorial e bom d+. vc conhece si ja tem algum ebook pra rails 2.x?. saudades desde argent.
lcostantino / 17.Jan.2008 at 08:16pm
Thanks for putting this together. Unfortunately, I’m a complete newcomer to ruby and rails. I followed the steps but they didn’t actually work for me. This appears to be great for someone who is already familiar with rails. The other 2 tutorials appear to be based on a pre 2.0 rails, and I have yet to actually get anything to come up other than the welcome page (I keep getting Unknown action or no method#index errors).
brad / 19.Jan.2008 at 01:02am
Bah Akita, mais uma vez dando um show de conhecimento e humanidade, compartilhando um pouco do seu conhecimento com a comunidade… Parabéns e obrigado pelo ótimo trabalho… E a segunda edição do livro??? Valew!
jardel / 19.Jan.2008 at 04:07am
thanks a lot for this great tutorial and many greetins from germany, düsseldorf !
chriss / 19.Jan.2008 at 09:01pm
I was just too frustrating for a complete novice to use the Agile book with 2.0. My plan is to learn 1.2 and then come back here when the terminology makes sense. Thanks for the work!
b
brian / 20.Jan.2008 at 10:30pm
Any chance of changing the layout of your page? I ask because the content of the blog occupies only about 1/3 of the screen, and that means that readers are forced to scroll in all of your examples. As a result, it is difficult to benefit from your well-expressed ideas.
dan / 28.Jan.2008 at 05:23pm
Hey Dan, there’s always room for improvement. If you know any good and unobtrusive Mephisto theme, please let me know.
akitaonrails / 28.Jan.2008 at 08:03pm
Fabio, I love the stuff you’ve been putting out. You turned me on to resource_controller this weekend, which prompted me to write an article which will appear on infoq this week. A second for formatting options on this page. I’d love to print this article, but it really looks ugly on print, all the good stuff is squeezed to the left. Any chance of a print style sheet? I know “beggars can’t be choosers.”
rick denatale / 29.Jan.2008 at 05:38pm
Hi Rick, I know you :-) I am most flattered by having you reading my stuff. I am glad you liked and you’re right: my blog is lacking a print version. You’re not the first to ask me this and I have to confess that it is stalled in my todo list. I’ve been very overwhelmed lately but I am surely making a print version as soon as possible, specially after yet another request. Thanks.
akitaonrails / 29.Jan.2008 at 06:06pm
hi Akita, for a lightweight mephisto theme, try micro.
seaofclouds / 30.Jan.2008 at 07:41am
This needs to be the first tutorial listed on the rails documentation page.
os / 31.Jan.2008 at 04:16am
At the tutorial point:
the redirect_to(@post, @comment) call already redirect to the post page!!!! the effect is the same of redirect_to(@post) ... how is this possible?
nobrin / 31.Jan.2008 at 08:31pm
Hey, I solved the mistery myself!!
errata: CHANGE redirect_to(@post, @comment) TO redirect_to([@post, @comment])
because redirect_to(@post, @comment) acts as redirect_to(@post)
bye!
nobrin / 31.Jan.2008 at 08:39pm
@nobrin, thanks you’re right, I just fixed this typo.
akitaonrails / 31.Jan.2008 at 09:15pm
Everything in the Tutorial work by me.
Now I want to make some additional actions (like ‘download’). And I define them in the controller.
I want to use the new action. So I add this line to my view(index.html.erb): ”<%= link_to ‘Download’, [:download, @project, document] %>
But when I call the view I receive the Error: “NoMethodError in Documents#index”
When I call the action directly via url I receive following error: ” ActiveRecord::RecordNotFound in DocumentsController#show” “Couldn’t find Document with ID=download AND (documents.project_id = 1)”
The routes.rb looks like: ” map.namespace :admin do |admin| admin.resources :people end
map.resources :documents
map.root :controller => ‘projects’ map.resources :projects, :has_many => :documents”
I hope you can help me.
Thanks.
robin / 01.Feb.2008 at 09:43am
The big fat “map.resources :documents” is comment in my routes.rb.
robin / 01.Feb.2008 at 09:45am
@robin: I think you misunderstood it. What you want is:
Right?
This means named URLs as:
Or route shortcuts as:
If you do:
It means that you want to call the custom action names ‘download’ in the projects controller, something as:
and
Get it?
akitaonrails / 01.Feb.2008 at 11:48am
Thanks for your quick answer.
robin / 01.Feb.2008 at 02:41pm
hey, thanks for the great tutorial…
dreamhost promo / 04.Feb.2008 at 01:40am
Great tutorial! I’ve gone through it and it’s helped me immensely. But I am having one problem I can’t get past.
It seems the child records in the has_many/belongs_to do not get the parent’s id in their foreign key fields. So, using the example from the tutorial, the Comment records do not refer back to any Post. If I modify the database directly, everything else works fine. It seems it is just the initial creation of the child record that is the problem.
Any advice would be greatly appreciated as I’ve searched quite a lot and seem to be stuck at this problem. Thank you!
matt / 05.Feb.2008 at 01:24am
Hi Fabio, Thanx for this great tut! This was my liftoff in Rails development (finally). I’m coming from PHP and I’m glad to erase that language from my life :-)
Rails rocks, and you too!
wout / 05.Feb.2008 at 05:48pm
Thankyou for excellent tutorial. I wonder if you did anything with the tests when doing this. In particular I’m having difficult moving the functional test to the admin section. Any chance of a tutorial update to deal with that?
andrew premdas / 08.Feb.2008 at 10:18am
I wanted to answer my own question from above, in case it may be any help to others.
I had missed the step in the controller changing from
Comment.new
to
@post.comments.build
I was using the PDF version of the tutorial, and this step wasn’t as obvious.
matt / 09.Feb.2008 at 01:21pm
If i wanted to have a link to a url like this:
localhost:3000/documents/?update=true
how would i format my link_to?
i tried <%= link_to ‘Refresh List’, documents_path, :update => ‘true’ %>
but it didnt work
mike / 15.Feb.2008 at 02:02pm
I got it to work with
<%= link_to ‘Refresh List’, {:action => ‘index’, :update => ‘True’} %>
but i wanted to do it using the named routes… is that possible
mike / 15.Feb.2008 at 02:19pm
Sorry for question from newbie. If it is not one thing, its another. Good Ruby 2.0 tutorial – as far as I got! Like style better than other books/tutorials so I am sticking with this one. Problem: When running rake db:migrate, got SQL error: “Access denied for user ‘root’@’localhost’ (using password: YES)” I installed InstantRails (WindowsXP), and think it may be using sqllite. How do I tell? How do I fix or change? —Thanks
nwgadgetguy / 16.Feb.2008 at 04:08am
Sorry about the last post – I didn’t realize the example put in a password. Changed it to my password, then got following error: “Unknown database ‘blog_development’ ” I though we set this up in the ‘database.yml’ file. ???
nwgadgetguy / 16.Feb.2008 at 04:15am
Back again. Found the problem. Needed to run ‘mysql’ and create the database from the shell (using ‘create database blog_development;’ etc.) Not mentioned above. Don’t know if it’s necessary, but I include ‘grant all on blog_development.* to ‘ODBC’@’localhost’;
nwgadgetguy / 16.Feb.2008 at 04:32am
Hi all, very good tutorial. Sorry if it’s a silly question, but I’m new in RoR, so I have a question. In the post view with the comments, is it possible to show error messages from the comment model ?
darwiin / 17.Feb.2008 at 02:38pm
Darwiin,
I’m a bit of a Rails newbie myself but I believe you just need to include:
<%= error_messages_for :comment %>
Somewhere in your views/posts/show.html.erb
pete / 17.Feb.2008 at 03:36pm
@Pete
Thanks for your answer. I’ve already tried this but it doesn’t seems to work.
darwiin / 17.Feb.2008 at 04:49pm
Hmm, I’ve just tried it and the best I’ve managed so far is to include ‘error_messages_for’ in the file that defines the comment form partial. This will show you any errors, but not inline on the post page, you get redirected to comments/new.
I have a feeling this can be overcome by altering the format.html { render :action => ‘new’ } line in the comments controller’s create method, but I’m not sure how!
pete / 17.Feb.2008 at 09:18pm
Hello,
I used the dynamic scaffolding to set up the application. Afterwards I changed to static. Is there a possibility to redo the “generate scaffold” after modifying the database e.g. inserting columns?
Thanks a lot!
heiko / 18.Feb.2008 at 06:47pm
yeah, is there something else in the routes.rb or something where we have to add something to make the partial work so that the edit.html.erb and new.html.erb link to the _comment.html.erb that we created?
leif / 19.Feb.2008 at 05:15am
Okay, I figured it out, I had some simple syntax problems.
<%= f.submit :button_name %>
instead of
<%= f.submit button_name %>
and <% render instead of <%= render
leif / 19.Feb.2008 at 07:27pm
Okay, I’ve made it as far as the admin, copied the views into views/admin/posts. The new.html.erb and edit.html.erb do not work for me. It hangs up on this line (line #5):
<% form_for([:admin, @post]) do |f| %>
and I get this error:
RuntimeError in Admin/posts#new
Showing admin/posts/new.html.erb where line #5 raised:
Called id for nil, which would mistakenly be 4—if you really wanted the id of nil, use object_id
what’s going on here??? I have double checked, triple checked, quadruple checked, etc, etc, etc and my code matches perfectly with the tutorial.
leif / 19.Feb.2008 at 11:58pm
That’s really strange. I just checked in my installation and it works fine. Can you double check with my source code ?
akitaonrails / 20.Feb.2008 at 04:55pm
Yeah, I was missing the ‘new’ and ‘edit’ actions in my controller from when I moved it under admin.
leif / 21.Feb.2008 at 06:47pm
Just got through the tutorial. Great work. Only had to start over once! I can see that this is really powerful stuff.
jon hanshew / 21.Feb.2008 at 07:50pm
great tutorial but when i try to open: http://localhost:3000/posts/1/comments
I get this: Couldn’t find Comment without an ID
Request Parameters shows: {“post_id”=>”1”}
fabian / 23.Feb.2008 at 10:56am
I posted a little tut, How to Do has_one Nesting in Rails 2.0 showing one way to handle nested routes with has_one associations.
Great tutorial, Fabio, you’re a life saver.
Ron
ron phillips / 27.Feb.2008 at 01:03pm
Gracias por el Tutorial Akita, muy bien explicado. Tu trabajo es de gran utilidad.
ruben / 28.Feb.2008 at 04:28am
Thanks for your nice post, it help me a lot about rail2, any way how can i set id to the from_for, i have searched a lot of place but i failed, can u help me?
<% form_for([:admin, @post]) do |f| %> ... <% end %>
mamun / 02.Mar.2008 at 03:27am
How would I use a path prefix to my restful routes?
ex.
Instead of “http://mysite.com/articles/1… Have “http://mysite.com/blog/articles/1…
Do i make a separate controller? script/generate controller Blog::Articles ?
Or is it something simple that I’m completely overlooking?
Great Tutorials!
rome / 02.Mar.2008 at 07:39pm
This tutorial is that thing which I was looking for. I must admit that rails 2.x changed many basic things, names conventions, so I think that your tut is the first that drives as through this version. Thanks a lot. Much more tuts like this.
regards kotosha
kotosha / 03.Mar.2008 at 05:15pm
NameError in Comments#index
I get this error when trying to access “http://localhost:3000/posts/1/comments” i have checked the post/comment.rb and they seem to be set up correctly.
jyeckel / 05.Mar.2008 at 02:42pm
@jYeCkeL : It seems you have some syntax error. Try to check it out again.
kotosha / 06.Mar.2008 at 06:47pm
@AkitaOnRails:
I have one question. Suppose I’d like to divide my posts into categories. I know that I have to generate another controller Categories but how to connect this f.e. with changes in routes.rb, relations with files. I would be grateful for any ideas, hints, suggestions.
kotosha / 06.Mar.2008 at 06:56pm
@anybody who can help
What if I want to view all comments for all posts on a single page? Obviously you wouldn’t want to do this in the blog example, but for my own purposes I need to display all child nodes on a page.
Thanks!
ryantuosto / 07.Mar.2008 at 12:35am
@RyanTuosto
I think you would do something like
Post.find(:all).each do |post| post.comments.each do |comment|justin / 08.Mar.2008 at 05:35pm
Oops… bad formatting.
Post.find(:all).each do |post|
post.comments.each do |comment|
//print the comment… <%= comment.body %>
end
end
justin / 08.Mar.2008 at 05:37pm
Actually if you just want all comments just go directly: Comment.find(:all)
akitaonrails / 08.Mar.2008 at 08:55pm
Is there a reason to not doing the DRY in the new and edit form of the post. (with the render :partial)
I was trying to do that in the admin interface and it gives me an error saying that posts/_post does not exists, which is true because the one that exists is admin/posts/_post, is there a way to tell the render :partial @posts to use the namespace? I have tried with <%= render :partial => @post … %> and with: <%= render :partial => [:admin, @post]... %> both dont work
luis sarti / 09.Mar.2008 at 02:33am
Hey, the way to fix the problem I found in the admin interface with render :partial is to put the string “post” instead of the variable @post.
So in my final new.html.erb and edit.html.erb , both have the <%= render :partial => “post”, :local => {...} %>
woohoo!!!
luis sarti / 09.Mar.2008 at 04:03pm
thanks for the great tutorial… found it really helpful.
techguide / 10.Mar.2008 at 03:49am
First, Thanks for this tutorial. Nevertheless, I’m a novice in RoR and I don’t understand where this error occurs.
undefined method `comment_url’ for #<commentscontroller:0xb73b9824>
niko / 10.Mar.2008 at 02:15pm
Thank you very much for this tutorial!!! I didn’t used rails for quite a while, and when i tryied the same steps as in pre 2.0 i recieved error after error. With your tutorial i finally get everything to work as it used to.
kubi / 11.Mar.2008 at 05:35pm
Great work!! thanks very much. Just one suggestion : it could be nice to provide one source archive with rails freezed. ;)
kabnot / 11.Mar.2008 at 05:35pm
@Niko:
It occurs in one of your views. Search for “post_comment_url(@post, @comment)” in this tutorial. You probably missed changing something that he changed in the tutorial.
justin / 12.Mar.2008 at 05:12pm
@AkitaOnRails:
Con