How can I update Rails controller variable on page refresh? - ruby-on-rails

Question

I have a controller that manages a list of Post and I added filter in it. The posts have rating system (0-5 rating). The filter lets user input what rating they want to see, and it will display inputted rating and higher.
For example, I have 10 posts, and 7 of them has rating of 3.5 and higher. If user inputs 3.5 in the rating filter, it will only displays 7 posts with the corresponding rating.
Here is the code:
index.html.erb
...
<%= form_tag posts_path, method: :get, class: "form-inline" do %> <!-- form_tag on posts path (index), use get method since we are displaying results and not altering/ submitting new data -->
<div class="rating form-group">
<%= label_tag :rating %>
<%= number_field_tag :rating, params[:rating], step: 0.5, min: 0, max: 5, class: "form-control" %>
<%= submit_tag "Search", name: nil, class: "btn btn-primary"%>
</div>
<% end %>
...
Here is my index:
def index
#posts = Post.all
#posts = Post.where("rating >= ?", params["rating"]) if params["rating"].present?
end
My problem is, I want to give users the ease of removing the filter whenever they do page refresh. How can I remove the filter every time user refreshes the page so that it displays all 10 posts again? Right now, if I want to display all 10 posts again after making the filter, I either have to go to the field box and delete the number 3.5 I inputted earlier and resubmit the form, or I have to change the url manually from
http://localhost:3000/posts?utf8...&rating=3 to http://localhost:3000/posts; I think it would be more convenient for users to just refresh the page.
I guess I can rephrase it as, how can I change my controller from #posts = Post.where... to #posts = Post.all again when user refreshes page?

Answer 1

I don't know what you routes are, but lets assume your posts_path is posts/index and routes to the index method in the PostsController.
First, I would change your routes config so that post/index will be matched to the index method in the PostsController for both :get and :post requests:
# config/routes.rb
match 'posts/index' => 'posts#index', as: 'posts', via: [:get, :post]
Next, I would change your form to use the :post method instead of :get:
<%= form_tag posts_path, method: :post, class: "form-inline" do %>
<div class="rating form-group">
<%= label_tag :rating %>
<%= number_field_tag :rating, params[:rating],
step: 0.5, min: 0, max: 5, class: "form-control" %>
<%= submit_tag "Search", name: nil, class: "btn btn-primary"%>
</div>
<% end %>
Finally, I would change the where clause your controller to accept params[:rating] if provided, but default to 0 if params[:rating] is nil:
def index
#posts = Post.where("rating >= ?", params[:rating]||=0)
end
This is of course assuming that you do not have negatively rated posts...if you do, you can default to a sufficiently negative number (that all posts are rated higher than).
Now, when the user submits the form, the url will no longer haveparams[:rating] in the query string.
Hope this helps!

Answer 2

The issue here is your query string stays when you refresh the page.
So one way to do it is to replace the url and remove the query string. With the history APi in modern browsers, you can do this.
history.replaceState({}, 'some title', '/');
You can simply plug this into your document / head ready callback. So after your user gets the response with ratings, you change the url back to the one without query string. So when it gets refreshed, it makes request to your server without the rating query string.
But keep in mind, your user won't be able to bookmark your page based of the ratings. If you want to do that, you will need to switch your get requst to post request. Check this wiki page out for more info.
https://en.wikipedia.org/wiki/Post/Redirect/Get