RailsGirls

This project is the starting point for my RailGirls workshop on Helpers, Concerns, and Decorators.

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Create a helper

Currently, the posts and comments have very ugly looking meta information. It looks something like this now:

On Sat, 25 Oct 2014 19:55:42 +0000, by [email protected]

We need to spruce that up a bit. For that we are going to use jQuery.timeago. Head over to their website and add the javascript file to your project.

After we're done it should look like this:

By [email protected], 2 days ago.

Add the javascript

Download the file and put it in vendor/assets/javascripts/jquery.timeago.js. Then add the following line to your app/assets/javascripts/application.js

//= require 'jquery.timeago'

Implement the helper

Check out the docs to see how we should format our HTML to enable it for jQuery.timeago. It should be something like this:

<abbr class="timeago" title="2014-10-25T09:24:17Z">October 25, 2014</abbr>

We want to have a helper method called timeago that we can call like so:

timeago(@post.created_at)

# or

timeago(@comment.created_at)

That helper method should take care of the entire HTML markup for us.

Enable the javascript

In order to enable the jQuery.timeago on these HTML snippets, we need to call it on every page. Do do so, we will use a tiny CoffeeScript snippet.

# app/assets/javascripts/timeago.js.coffee
$ ->
  $("abbr.timeago").timeago()

That's it!

Create a Decorator

As you can see in app/views/posts/show.html.erb and app/views/posts/index.html.erb, we have to call .html_safe on the content of a blog post, in order to have all the HTML markup rendered, rather than the HTML being rendered as text. We are bound to forget that at some point, so we should decorate it, to make sure that all decorated posts have their content rendered as html_safe.

Start with removing the .html_safe calls from the following files:

app/views/comments/_comment.html.erb
app/views/posts/_post.html.erb
app/views/posts/show.html.erb

Add the Draper gem

We are going to use Draper to help us with the decoration process. Add this to your Gemfile:

gem 'draper'

And run bundle install

Then create the decorator:

class PostDecorator < Draper::Decorator
  delegate_all

  def content
    object.content.html_safe
  end
end

Now, find the instances of @post and @posts in the PostsController and make sure they are decorated. Consult the README of Draper to get you started on usage of the decorator gem.

Bonus Note that we have removed html_safe from the comments view as well! Now go and make a decorator for your Comments too!

Create a concern

When you open up the Post model, you will see it has a number of methods that deal with publishing posts. Now, imagine we want to add these methods to Comment as well. We could just copy over the methods to the model file, but we could also extract this out into a concern, so we do not need to copy this, and we can just include it in both the Post and the Comment models!

Create the concern

# app/models/concerns/shared/publishable.rb

module Shared::Publishable
  extend ActiveSupport::Concern

  included do
    # Move the methods from the Post model here!
  end
end

Now include it in the Post model

# app/models/post.rb

class Post < ActiveRecord::Base
  include Shared::Publishable

  # ...
end

And in the Comment model as well

# app/models/comment.rb

class Comment < ActiveRecord::Base
  include Shared::Publishable

  # ...
end

Now boot up a Rails console and check on some comments' published status, e.g.:

$ spring rails console
$> Comment.last.published?

That should work for both Comment and Post models!