Undefined method for object defined in controller Rails - ruby-on-rails

Question

I have a view with a form and a table that displays some data from the database. Whenever I try to access the object from my controller in my view I get undefined method domain for "https://www.lookagain.co.uk/":String. But if do <%#savedHTML = ScrapedPage.all%> everything works fine. I know the I should not do that in the view as it defeats to purpose of MVC but I don't seem to fin a fix.
View:
<%= stylesheet_link_tag "masterstyles.css" %>
<% #url = 'default' %>
<%= form_for #url, :url => {:controller => "page_scraper", :action => "scrape"} do |f| %>
<%= f.text_field (:url) %>
<%= f.submit "Scrape" %>
<% end %>
<%#domain ='default'%>
<%#date ='default'%>
<%= form_for #domain, :url => {:controller => "page_scraper", :action => "compare"} do |f| %>
<%=select_tag 'domain', options_for_select(#savedHTML.collect{ |u| [u.domain, u.domain] })%>
<%=select_tag 'date', options_for_select(#savedHTML.collect{ |u| [u.created_at, u.created_at] })%>
<%= f.submit "compare" %>
<% end %>
<div class="subjects index">
<h2>FGH Page Scraper</h2>
<table class="listing" summary="Links list">
<tr class="header">
<th>ID</th>
<th>link</th>
<th>Created at</th>
<th>Updated at</th>
</tr>
<% #savedHTML.each do |page| %>
<tr>
<td><%= page.id %></td>
<td><%= page.domain %></td>
<td class="center"><%= page.created_at %></td>
<td class="center"><%= page.updated_at %></td>
<td class="actions">
<%= link_to("Delete", {:controller => 'page_scraper', :action => 'delete', :id => page.id}, :class => 'action delete') %>
</td>
</tr>
<% end %>
</table>
</div>
Controller:
class PageScraperController < ApplicationController
require 'nokogiri'
require 'open-uri'
require 'diffy'
require 'htmlentities'
def scrape
#url = watched_link_params[:url].to_s
puts "LOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOG#{#url}"
#page = Nokogiri::HTML(open(#url))
coder = HTMLEntities.new
#encodedHTML = coder.encode(#page)
create
end
def index
#savedHTML = ScrapedPage.distinct.pluck(:domain)
end
def show
#savedHTML = ScrapedPage.distinct.pluck(:domain)
end
def new
#savedHTML = ScrapedPage.new
end
def create
#savedHTML = ScrapedPage.create(domain: #url, html: #encodedHTML, css: '', javascript: '')
if #savedHTML.save
puts "ADDED TO THE DATABASE"
redirect_to(root_path)
else
puts "FAILED TO ADD TO THE DATABASE"
end
end
def edit
end
def upadate
end
def delete
#savedHTML = ScrapedPage.find(params[:id])
end
def destroy
#savedHTML = ScrapedPage.find(params[:id])
#savedHTML.destroy
redirect_to(root_path)
end
def compare
#domain = params[:domain].to_s
puts #domain
redirect_to(root_path)
#timestamp
end
def watched_link_params
params.require(:default).permit(:url)
end
def compare_params
params.require(:domain).permit(:domain)
end
end

Answer 1

The problem is that in your controller you are saving only string-values to #savedHTML variable (pluck will give you only an array of attributes from given objects). Therefore you cant ask "some_string".domain because String class doesn't have a domain method.
If you have a domain method on ScrapedPage object then in your controller action (index or show - whatever you are dealing with) you should replace
#savedHTML = ScrapedPage.distinct.pluck(:domain)
with
#savedHTML = ScrapedPage.select(:domain).distinct
The latter will give you unique ScrapedPage objects based on domain value. Look here for further info and examples.
NB! also a tip for refactoring:
Use strong parameters under private section. Also, if you have the same query in your controller twice in different actions then it is better to make it in before_action like this:
class PageScraperController < ApplicationController
before_action :set_saved_html, only: %i[index show]
def index
end
def show
end
private
def watched_link_params
params.require(:default).permit(:url)
end
def compare_params
params.require(:domain).permit(:domain)
end
def set_saved_html
#savedHTML = ScrapedPage.select(:domain).distinct
end
end