Passing boolean parameter to rails controller?

Question

I have a post object with a boolean called :published. The the definition for index in the controller looks like this:

def index
  @posts = Post.all

  respond_to do |format|
    format.html # index.html.erb
    format.json { render json: @posts }
  end
end

And this links to that page:

<%= link_to 'All posts', posts_path %>

Let's say instead I want the option of showing only posts where post.published? is true.

Should I have a separate method in the controller to handle the case where only :published posts would be shown?
Can I alter the index method to handle a parameter being passed to it?
What would the link_to look like?

Christian Fazzini · Accepted Answer · 2012-08-27 21:19:28Z

3

In theory, for filtering results by keywords / categories, it is fine to display the logic in the same controller via a param. I would have it as:

<%= link_to 'All posts', posts_path(:published => true) %>

Then in your controller / index action:

def index
  @posts = Post.all
  @posts = @posts.where(:published => true) if params[:published].present?
  ...

To refactor your code, I would scope the method in the model, with something like:

scope :published, where(:published => true)

Then in your controller you can just have:

@posts = @posts.published if params[:published].present?

For more information on chaining / model scopes: http://guides.rubyonrails.org/active_record_querying.html#scopes

edited Aug 27, 2012 at 21:19

answered Aug 27, 2012 at 20:05

Christian Fazzini

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6 Comments

Kevin K Over a year ago

Thank you for the response. It doesn't give me an error, but it still lists all the posts, not just the published ones.

Christian Fazzini Over a year ago

You might want to do some debugging on your end. Is the code executing if a param is passed? Are there any @posts where published is true? In Rails console, run Post.where(:published => true). Does that return anything?

Kevin K Over a year ago

Post.where(:published => true) works in console. There are some posts where published is true. I'm not sure how to test if the code is executing. I think that the param may not be getting passed.

Kevin K Over a year ago

changed to the link to: <%= link_to 'Published Posts', posts_path(:published => :true) %> and that seemed to pass the paramater

Christian Fazzini Over a year ago

Made the necessary edits on my post. Glad its now working for you

|

Scott McMillin · Accepted Answer · 2012-08-27 20:47:38Z

2

To keep it really simple (no scopes), just do the following

def index
  @posts = if params[:published].present?
    Post.where(:published => true)
  else
    Post.all
  end
...

And then to add the link with params do

%= link_to 'Published Posts', posts_path(:published => true) %>

answered Aug 27, 2012 at 20:47

Scott McMillin

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1 Comment

Rob Volk Over a year ago

Thing is if you do it this way, you need to specify a value for the parameter, otherwise Rails discards it. And this is pretty confusing: link_to 'Published Posts', posts_path(:published => false) => will still include published posts

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