diff options
Diffstat (limited to 'guides/source/getting_started.md')
| -rw-r--r-- | guides/source/getting_started.md | 87 |
1 files changed, 54 insertions, 33 deletions
diff --git a/guides/source/getting_started.md b/guides/source/getting_started.md index 26360e815b..9b2fa315a1 100644 --- a/guides/source/getting_started.md +++ b/guides/source/getting_started.md @@ -138,7 +138,7 @@ application. Most of the work in this tutorial will happen in the `app/` folder, |config/|Configure your application's runtime rules, routes, database, and more. This is covered in more detail in [Configuring Rails Applications](configuring.html)| |config.ru|Rack configuration for Rack based servers used to start the application.| |db/|Contains your current database schema, as well as the database migrations.| -|Gemfile<br />Gemfile.lock|These files allow you to specify what gem dependencies are needed for your Rails application. These files are used by the Bundler gem. For more information about Bundler, see [the Bundler website](http://gembundler.com) | +|Gemfile<br>Gemfile.lock|These files allow you to specify what gem dependencies are needed for your Rails application. These files are used by the Bundler gem. For more information about Bundler, see [the Bundler website](http://gembundler.com) | |lib/|Extended modules for your application.| |log/|Application log files.| |public/|The only folder seen to the world as-is. Contains the static files and compiled assets.| @@ -264,11 +264,14 @@ Blog::Application.routes.draw do end ``` -If you run `rake routes`, you'll see that all the routes for the -standard RESTful actions. +If you run `rake routes`, you'll see that it has defined routes for all the +standard RESTful actions. The meaning of the prefix column (and other columns) +will be seen later, but for now notice that Rails has inferred the +singular form `post` and makes meaningful use of the distinction. ```bash $ rake routes + Prefix Verb URI Pattern Controller#Action posts GET /posts(.:format) posts#index POST /posts(.:format) posts#create new_post GET /posts/new(.:format) posts#new @@ -394,9 +397,27 @@ Edit the `form_for` line inside `app/views/posts/new.html.erb` to look like this <%= form_for :post, url: posts_path do |f| %> ``` -In this example, the `posts_path` helper is passed to the `:url` option. What Rails will do with this is that it will point the form to the `create` action of the current controller, the `PostsController`, and will send a `POST` request to that route. - -By using the `post` method rather than the `get` method, Rails will define a route that will only respond to POST methods. The POST method is the typical method used by forms all over the web. +In this example, the `posts_path` helper is passed to the `:url` option. +To see what Rails will do with this, we look back at the output of +`rake routes`: +```bash +$ rake routes + Prefix Verb URI Pattern Controller#Action + posts GET /posts(.:format) posts#index + POST /posts(.:format) posts#create + new_post GET /posts/new(.:format) posts#new +edit_post GET /posts/:id/edit(.:format) posts#edit + post GET /posts/:id(.:format) posts#show + PATCH /posts/:id(.:format) posts#update + PUT /posts/:id(.:format) posts#update + DELETE /posts/:id(.:format) posts#destroy + root / welcome#index +``` +The `posts_path` helper tells Rails to point the form +to the URI Pattern associated with the `posts` prefix; and +the form will (by default) send a `POST` request +to that route. This is associated with the +`create` action of the current controller, the `PostsController`. With the form and its associated route defined, you will be able to fill in the form and then click the submit button to begin the process of creating a new post, so go ahead and do that. When you submit the form, you should see a familiar error: @@ -531,27 +552,19 @@ and change the `create` action to look like this: ```ruby def create - @post = Post.new(post_params) + @post = Post.new(params[:post]) @post.save redirect_to @post end - -private - def post_params - params.require(:post).permit(:title, :text) - end ``` Here's what's going on: every Rails model can be initialized with its respective attributes, which are automatically mapped to the respective -database columns. In the first line we do just that (remember that -`post_params` contains the attributes we're interested in). Then, -`@post.save` is responsible for saving the model in the database. -Finally, we redirect the user to the `show` action, -which we'll define later. - -TIP: Note that `def post_params` is private. This new approach prevents an attacker from setting the model's attributes by manipulating the hash passed to the model. For more information, refer to [this blog post about Strong Parameters](http://weblog.rubyonrails.org/2012/3/21/strong-parameters/). +database columns. In the first line we do just that +(remember that `params[:post]` contains the attributes we're interested in). +Then, `@post.save` is responsible for saving the model in the database. +Finally, we redirect the user to the `show` action, which we'll define later. TIP: As we'll see later, `@post.save` returns a boolean indicating whether the model was saved or not. @@ -631,6 +644,11 @@ Visit <http://localhost:3000/posts/new> and give it a try!  +TIP: Note that `def post_params` is private. This new approach prevents an attacker from +setting the model's attributes by manipulating the hash passed to the model. +For more information, refer to +[this blog post about Strong Parameters](http://weblog.rubyonrails.org/2012/3/21/strong-parameters/). + ### Listing all posts We still need a way to list all our posts, so let's do that. @@ -726,7 +744,7 @@ TIP: In development mode (which is what you're working in by default), Rails reloads your application with every browser request, so there's no need to stop and restart the web server when a change is made. -### Allowing the update of fields +### Adding Some Validation The model file, `app/models/post.rb` is about as simple as it can get: @@ -741,8 +759,6 @@ your Rails models for free, including basic database CRUD (Create, Read, Update, Destroy) operations, data validation, as well as sophisticated search support and the ability to relate multiple models to one another. -### Adding Some Validation - Rails includes methods to help you validate the data that you send to models. Open the `app/models/post.rb` file and edit it: @@ -1021,9 +1037,14 @@ content: ``` Everything except for the `form_for` declaration remained the same. -How `form_for` can figure out the right `action` and `method` attributes -when building the form will be explained in just a moment. For now, let's update the -`app/views/posts/new.html.erb` view to use this new partial, rewriting it +The reason we can use this shorter, simpler `form_for` declaration +to stand in for either of the other forms is that `@post` is a *resource* +corresponding to a full set of RESTful routes, and Rails is able to infer +which URI and method to use. +For more information about this use of `form_for`, see +[Resource-oriented style](//api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-form_for-label-Resource-oriented+style). + +Now, let's update the `app/views/posts/new.html.erb` view to use this new partial, rewriting it completely: ```html+erb @@ -1294,11 +1315,11 @@ So first, we'll wire up the Post show template <h2>Add a comment:</h2> <%= form_for([@post, @post.comments.build]) do |f| %> <p> - <%= f.label :commenter %><br /> + <%= f.label :commenter %><br> <%= f.text_field :commenter %> </p> <p> - <%= f.label :body %><br /> + <%= f.label :body %><br> <%= f.text_area :body %> </p> <p> @@ -1374,11 +1395,11 @@ template. This is where we want the comment to show, so let's add that to the <h2>Add a comment:</h2> <%= form_for([@post, @post.comments.build]) do |f| %> <p> - <%= f.label :commenter %><br /> + <%= f.label :commenter %><br> <%= f.text_field :commenter %> </p> <p> - <%= f.label :body %><br /> + <%= f.label :body %><br> <%= f.text_area :body %> </p> <p> @@ -1440,11 +1461,11 @@ following: <h2>Add a comment:</h2> <%= form_for([@post, @post.comments.build]) do |f| %> <p> - <%= f.label :commenter %><br /> + <%= f.label :commenter %><br> <%= f.text_field :commenter %> </p> <p> - <%= f.label :body %><br /> + <%= f.label :body %><br> <%= f.text_area :body %> </p> <p> @@ -1470,11 +1491,11 @@ create a file `app/views/comments/_form.html.erb` containing: ```html+erb <%= form_for([@post, @post.comments.build]) do |f| %> <p> - <%= f.label :commenter %><br /> + <%= f.label :commenter %><br> <%= f.text_field :commenter %> </p> <p> - <%= f.label :body %><br /> + <%= f.label :body %><br> <%= f.text_area :body %> </p> <p> |