How to reload my index page - ruby-on-rails

Question

I have this filter in my tutos index:
= simple_form_for :query, url: tutos_path, method: :get, wrapper: :inline_form, html: {class: 'form-inline'} do |f|
= f.input :keyword, placeholder: "Keyword"
= f.input :category, collection: (Category.all.map {|c| c.name}) , prompt: "Select a category"
= f.input :user, collection: (User.order('nickname ASC').all.map {|u| u.nickname}), prompt: "Select a user"
= f.button :submit, "Find", class:"btn btn-warning"
= link_to t("search_form.best"), best_voted_path, class: "btn btn-default"
= link_to t("search_form.all"), tutos_path, class: "btn btn-default"
-if user_signed_in?
= link_to t("search_form.create"), new_tuto_path, class:"btn btn-success"
After filtering I can't get back to my tutos_path through my link_to:
I have this error:
NoMethodError at /en/tutos
undefined method `[]' for nil:NilClass
in my controller I have:
def index
#tutos = Tuto.all
filter_tutos
end
def filter_tutos
#tutos = Tuto.search(params[:query][:keyword]).includes(:user, :category) if params[:query][:keyword].present?
#tutos = Tuto.joins(:user).where('users.nickname LIKE ?', params[:query][:user]) if params[:query][:user].present?
#tutos = Tuto.joins(:category).where('categories.name LIKE ?', params[:query][:category]) if params[:query][:category].present?
end

Answer 1

The error is coming from your params[:query][:keyword].present? and the other ones alike, because it's evaluated as params, then params[:query]. If one of these evaluates to nil, and then trying to run nil[:query], hence [] isn't defined on NilClass, it returns an error.
You'll need to check for nil in the function:
def filter_tutos
return if params[:query].nil? # Don't bother, if the query is nil
#tutos = Tuto.search(params[:query][:keyword]).includes(:user, :category) if params[:query][:keyword].present?
#tutos = Tuto.joins(:user).where('users.nickname LIKE ?', params[:query][:user]) if params[:query][:user].present?
#tutos = Tuto.joins(:category).where('categories.name LIKE ?', params[:query][:category]) if params[:query][:category].present?
end
As far as I remember, params is always set in the Controller. If this is not the case, you'll need to adapt your nil-checks for that as well.
To make it fit your own answer, and have a fallback method, you could do like so, to check if
def index
filter_tutos if params[:query].present?
#tutos ||= Tuto.all
end
To make sure that #tutos are set. It'll be set to Tuto.all if it's nil from the method filter_tutos.

Answer 2

I finally found out...
in my controller:
def index
if params[:query].present?
filter_tutos
else
#tutos = Tuto.all
end
end
in my view instead of my = link_to t("search_form.all"), tutos_path, class: "btn btn-default"
I did:
= link_to t("search_form.all"), {controller: 'tutos', action: 'index'}, class: "btn btn-success"