From aae77d2839349eb5034d6a72bfc351a532f1e6d7 Mon Sep 17 00:00:00 2001 From: Ryan Bigg Date: Fri, 14 Oct 2011 18:06:23 +1100 Subject: [engines guide] complete comments resource generation --- railties/guides/source/engines.textile | 65 ++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) (limited to 'railties') diff --git a/railties/guides/source/engines.textile b/railties/guides/source/engines.textile index 616ea16b7a..12c454abd1 100644 --- a/railties/guides/source/engines.textile +++ b/railties/guides/source/engines.textile @@ -261,14 +261,79 @@ Next, there needs to be a form so that comments can be created on a post. To add Next, the partial that this line will render needs to exist. Create a new directory at +app/views/blorgh/comments+ and in it a new file called +_form.html.erb+ which has this content to create the required partial: +

New comment

<%= form_for [@post, @post.comments.build] do |f| %>

<%= f.label :text %>
<%= f.text_area :text %>

+ <%= f.submit %> <% end %> +This form, when submitted, is going to attempt to post to a route of +posts/:post_id/comments+ within the engine. This route doesn't exist at the moment, but can be created by changing the +resources :posts+ line inside +config/routes.rb+ into these lines: + + +resources :posts do + resources :comments +end + + +The route now will exist, but the controller that this route goes to does not. To create it, run this command: + + +$ rails g controller comments + + +This will generate the following things: + + +create app/controllers/blorgh/comments_controller.rb +invoke erb + exist app/views/blorgh/comments +invoke test_unit +create test/functional/blorgh/comments_controller_test.rb +invoke helper +create app/helpers/blorgh/comments_helper.rb +invoke test_unit +create test/unit/helpers/blorgh/comments_helper_test.rb +invoke assets +invoke js +create app/assets/javascripts/blorgh/comments.js +invoke css +create app/assets/stylesheets/blorgh/comments.css + + +The form will be making a +POST+ request to +/posts/:post_id/comments+, which will correspond with the +create+ action in +Blorgh::CommentsController+. This action needs to be created and can be done by putting the following lines inside the class definition in +app/controllers/blorgh/comments_controller.rb+: + + +def create + @post = Post.find(params[:post_id]) + @comment = @post.comments.build(params[:comment]) + flash[:notice] = "Comment has been created!" + redirect_to post_path +end + + +This is the final part required to get the new comment form working. Displaying the comments however, is not quite right yet. If you were to create a comment right now you would see this error: + + + Missing partial blorgh/comments/comment with {:handlers=>[:erb, :builder], :formats=>[:html], :locale=>[:en, :en]}. Searched in: + * "/Users/ryan/Sites/side_projects/blorgh/test/dummy/app/views" + * "/Users/ryan/Sites/side_projects/blorgh/app/views" + + +The engine is unable to find the partial required for rendering the comments. Rails has looked firstly in the application's (+test/dummy+) +app/views+ directory and then in the engine's +app/views+ directory. When it can't find it, it will throw this error. The engine knows to look for +blorgh/comments/comment+ because the model object it is receiving is from the +Blorgh::Comment+ class. + +This partial will be responsible for rendering just the comment text, for now. Create a new file at +app/views/blorgh/comments/_comment.html.erb+ and put this line inside it: + + +<%= comment_counter + 1 %>. <%= comment.text %> + + +The +comment_counter+ local variable is given to us by the +<%= render @post.comments %>+ call, as it will define this automatically and increment the counter as it iterates through each comment. It's used in this example to display a small number next to each comment when it's created. + +That completes the comment function of the blogging engine. Now it's time to use it within an application. h3. Hooking into application -- cgit v1.2.3