how to handle ActiveRecord::RecordNotFound in rails controller?

Question

I have an app with user and events. Each user has several events. When a user wants to see a specific event he will get to this action:

def show
  begin
    @use         


        

Answer 1

Put return after redirect

begin
 @userEvents = current_user.event
 @event = @userEvents.find(params[:id])
rescue ActiveRecord::RecordNotFound  
 redirect_to :controller => "main", :action => "index"
 return
end

Answer 2

In application controller, please write:

    rescue_from (ActiveRecord::RecordNotFound) { |exception| handle_exception(exception, 404) }

   protected

    def handle_exception(ex, status)
        render_error(ex, status)
        logger.error ex   
    end

    def render_error(ex, status)
        @status_code = status
        respond_to do |format|
          format.html { render :template => "error", :status => status }
          format.all { render :nothing => true, :status => status }
       end
    end

Create a page error.html.erb

<div class="page-header">
  <h1>
    <%= t "errors.#{@status_code}.heading" %>
    <small><%= t "errors.#{@status_code}.subheading" %></small>
  </h1>
</div>
<p><%= t "errors.#{@status_code}.description" %></p>
<% if defined? root_path %>
  <%= link_to t(:return_to_home), root_path %>
<% end %>

and in en.yml

en:
  errors:
    "404":
      description: "The page you are looking for does not exist!"
      heading: "Record not found"
      subheading: ""

Answer 3

Calling redirect_to doesn't return from your action method which is why moving on to the respond_to block causes the DoubleRenderError. One way to fix that is with:

redirect_to :controller => "main", :action => "index" and return

However, a better solution might be to either rescue from this exception declaratively or just let it propagate to the client. The former look like this:

class YourController < ActionController::Base

  rescue_from ActiveRecord::RecordNotFound, with: :dude_wheres_my_record

  def show
    # your original code without the begin and rescue
  end

  def dude_where_my_record
    # special handling here
  end
end

If you just let the exception fester the user will see the public/404.html page in production mode.