Rails - pass variable to different page on redirect

Question

appreciate if you can help. I added pg_search to my project and need to redirect user back if there is no search results at all. Here is my search controller.

/app/controllers/results_controller.rb

class ResultsController < FrontendController
  def index
    @search_results = PgSearch.multisearch(params[:query])
    if @search_results.empty?
      redirect_to :back(@search_results)
    end
  end
end

And here is my layout where i'm trying to catch search result:

/app/views/layouts/application.html.slim
...
    .search-result class="#{'visible' unless @search_results?}
      ' 0 results
...

and all I get is

/app/views/layouts/application.html.slim:165: syntax error, unexpected ')' ...isible' unless@search_results?))).to_s)); _temple_html_attri... ... ^ 
/app/views/layouts/application.html.slim:168: syntax error, unexpected keyword_do_cond, expecting ')' ...method: :get, role: 'search' do; ... ^ 
/app/views/layouts/application.html.slim:171: syntax error, unexpected keyword_end, expecting ')' ; end; @output_buffer.safe_concat(... ^ /app/views/layouts/application.html.slim:194: syntax error, unexpected keyword_ensure, expecting ')' 
/app/views/layouts/application.html.slim:196: syntax error, unexpected keyword_end, expecting ')'

I several different approaches from Stackoverflow, but nothing helped. What am I doing wrong? Rails 4.2.5.1, Ruby 2.2.3

Answer 1

Don't redirect back. Instead render a view that tells the user that there is no search results. Otherwise you get an endless loop when you hit the back button.

class ResultsController < FrontendController
  def index
    @search_results = PgSearch.multisearch(params[:query])
  end
end

---

# app/views/results/index.html
<% if @search_results.any? do %>
  <% @search_results.each do |r| %>

  <% end %>
<% else %>
  No results.
  <%= render 'some_kind_of_form' %>
<% end >

Why the syntax error?

In redirect_to :back :back is a literal symbol. You can't call literals in Ruby:

irb(main):001:0> :foo("bar")
SyntaxError: (irb):1: syntax error, unexpected '(', expecting end-of-input
:foo("bar")

If you want to augment the the url use url_for(:back) which is the same as request.referrer.

# see https://ruby-doc.org/stdlib-2.1.2/libdoc/uri/rdoc/URI/HTTP.html
uri = URI(url_for(:back))
uri.query = { foo: 'bar' }.to_query
redirect_to uri

If you want to get the route object you can do:

Rails.application.routes.recognize_path(url_for(:back), method: :get)