SQL optimisation rolled back. It lead to access problems.

app/controllers/packages_controller.rb

@@ -288,9 +288,8 @@ class PackagesController < ApplicationController
   
   # Return packages matching the criteria given by parameters
   def query_packages
-    # Eager load the screenshots to avoid N+1 queries to check Screenshot.accessible_by later
+    packages = Package.order(visits: :desc)
-    packages = Package.includes(:screenshots).order(visits: :desc)
+
-  
     # text search
     if params[:search].present?
       logger.debug "Searching for #{params[:search]}"
@@ -300,15 +299,11 @@ class PackagesController < ApplicationController
     case params[:show]
     when 'with'
       # Enrich the result with the screenshots readable by the current user (CanCanCan)
-      packages = packages.where(screenshots: Screenshot.accessible_by(current_ability, :view))
+      packages = packages.with_screenshots
       logger.debug 'Limiting packages to those with screenshots'
     when 'without'
       packages = packages.without_screenshots
       logger.debug 'Limiting packages to those without screenshots'
-    else
-      packages = packages.where(screenshots: Screenshot.accessible_by(current_ability, :view)).or(
-        packages.without_screenshots)
-
     end
 
     return packages

app/controllers/welcome_controller.rb

@@ -1,7 +1,6 @@
 class WelcomeController < ApplicationController
   def home
-    # TODO: Only approved screenshots!
+    @newest_upload = Screenshot.where(approved: true).first
-    @newest_upload = Screenshot.newest.accessible_by(current_ability, :view).first
 
     @most_popular_package = Package.with_screenshots.order(visits: :desc).first
 

app/models/ability.rb

@@ -33,6 +33,12 @@ class Ability
     # https://github.com/CanCanCommunity/cancancan/wiki/Defining-Abilities
 
     if user.present? # Logged-in users
+      # Allow to view all public/approved screenshots
+      can :view, Screenshot, approved: true
+      # Allow to view any own uploads (even not-yet-approved)
+      can :view, Screenshot, user_id: user.id
+      can :destroy, Screenshot, user_id: user.id
+
       if user.admin_role?
         can :approve, Screenshot
         can :destroy, Screenshot
@@ -45,12 +51,6 @@ class Ability
         can :view, Screenshot
         can :destroy, Screenshot
       end
-      if user.pseudo?
-        # Allow to view all public/approved screenshots
-        can :view, Screenshot, approved: true
-        # Allow to view any own uploads (even not-yet-approved)
-        can :view, Screenshot, user_id: user.id
-      end
     else # Nobody logged in
       can :view, Screenshot, approved: true
     end

app/models/package.rb

@@ -57,7 +57,7 @@ class Package < ApplicationRecord
   end
 
 
-  # Return a query of all packages that have screenshots
+  # Return a query of all packages that do not have screenshots
   def self.without_screenshots
     # Query for all packages who's ID does not appear in a screenshot's "package_id" field
     subselect = Screenshot.select(:package_id)

app/views/packages/browse.slim

@@ -18,7 +18,8 @@
             .cell.pkgcard data-equalizer-watch=true
               a.black href=package_path(name: pkg.name)
                 .image
-                  = small_img(pkg.screenshots.first, cls: '')
+                  / This leads to an N+1 SQL query for each image. Ideas for optimization welcome.
+                  = small_img(pkg.screenshots.accessible_by(current_ability, :view).first, cls: '')
                 .text.pkgname
                   = pkg.name
                 .text
@@ -29,7 +30,8 @@
             .small-12.medium-4.cell.pkgcard
               a.black href=package_path(name: pkg.name)
                 .image
-                  = small_img(pkg.screenshots.first, cls: '')
+                  / This leads to an N+1 SQL query for each image. Ideas for optimization welcome.
+                  = small_img(pkg.screenshots.accessible_by(current_ability, :view).first, cls: '')
             .small-12.medium-8.cell
               h2
                 a href=package_path(name: pkg.name)