Handles 404 with a custom page using the app template

To have a nicer response to visitors of 404s, versus the static one, so user 
can still use the nav/search and continue to other pages on the site.

app/controllers/application_controller.rb

@@ -7,6 +7,8 @@ class ApplicationController < ActionController::Base
 
   before_action :sentry_user_context, if: :current_user
 
+  rescue_from ActiveRecord::RecordNotFound, :with => :error_not_found
+
   def require_login
     if current_user.nil?
       redirect_to signin_url(goto: request.path), flash: { error: "You must first sign in to access this page" }
@@ -24,6 +26,13 @@ def require_superadmin
 
   around_action :user_time_zone, if: :current_user
 
+  def error_not_found
+    respond_to do |format|
+      format.html { render "/application/errors/404", :status => :not_found }
+      format.all { head :not_found }
+    end
+  end
+
 private
 
   def user_time_zone(&block)

app/controllers/labs_controller.rb

@@ -11,6 +11,8 @@ class LabsController < ApplicationController
 
   # authorize_actions_for Lab, actions: { map: :read, manage_admins: :update}
 
+  rescue_from ActiveRecord::RecordNotFound, :with => :record_not_found
+
   def embed
     @labs = Lab.with_approved_state
     # render :embed, layout: false
@@ -75,11 +77,7 @@ def create
   end
 
   def show
-    begin
-      @lab = with_approved_or_pending_state(params[:id])
-    rescue ActiveRecord::RecordNotFound
-      return redirect_to root_path, notice: 'Lab not found'
-    end
+    @lab = with_approved_or_pending_state(params[:id])
     # @people = [@lab.creator]
     @employees = @lab.employees.includes(:user).active.order('employees.id ASC')
     @machines = @lab.machines.includes(:brand, :tags)
@@ -135,6 +133,13 @@ def allow_iframe
     #  From http://jerodsanto.net/2013/12/rails-4-let-specific-actions-be-embedded-as-iframes/
   end
 
+  def record_not_found
+    respond_to do |format|
+      format.html { render "404", :status => :not_found }
+      format.all { head :not_found }
+    end
+  end
+
   def lab_params
     params.require(:lab).permit(
       :activity_status,

app/views/application/errors/404.html.haml

@@ -0,0 +1,7 @@
+.jumbotron.text-center
+  = title "Page Not Found - 404 error", class: "text-danger"
+
+  %br
+
+  %p Sorry, the page you were looking for could not be found.
+

app/views/labs/404.html.haml

@@ -0,0 +1,11 @@
+.jumbotron.text-center
+  = title "Lab Not Found - 404 error", class: "text-danger"
+
+  %br
+
+  %p Unable to find any Lab matching the URL provided. Try searching or browse through the list of labs.
+
+  %br
+
+  = link_to t("views.header.labs"), labs_path, class: "btn btn-primary btn-lg"
+

config/routes.rb

@@ -162,6 +162,8 @@
 
     root to: 'static#alt'
 
+    match '*unmatched', to: 'application#error_not_found', via: :all
+
   end
 
   constraints(ApiSubdomain) do