Delivering proper PNG 404 images for thumbnails and large images

app/controllers/packages_controller.rb

@@ -92,11 +92,39 @@ class PackagesController < ApplicationController
       return
     end
 
-    # Send the thumbnail
+    # Send the thumbnail (uses X-Sendfile or similar if possible)
-    # TODO: Make sure it uses X-Sendfile correctly in production
     send_file @screenshot.image.path(:thumb), type: "image/png", disposition: 'inline'
   end
 
+  # Returns a large screenshot image if posssible.
+  # If the package is not found it returns a dummy image along with status 404.
+  # If the package is found but has no screenshots then it also returns a
+  # dummy image along with status 404.
+  def screenshot
+    @package = Package.find_by(name: params[:name])
+    unless @package
+      screenshot404
+      return
+    end
+
+    # Called as /thumbnail-with-version/:name/:version
+    if params[:version]
+      @screenshot = @package.best_screenshot_for_version(params[:version])
+    # Called as /thumbnail/:name
+    else
+      @screenshot = @package.screenshots.first
+    end
+
+    # Return a 404 if the package has no screenshots or the image was not found
+    unless @screenshot and @screenshot.image.path
+      screenshot404
+      return
+    end
+
+    # Send the thumbnail (uses X-Sendfile or similar if possible)
+    send_file @screenshot.image.path(:large), type: "image/png", disposition: 'inline'
+  end
+
   # Receives a form with a simple text field 'description' so that users can update
   # the description of their screenshot.
   def update_screenshot_description
@@ -120,9 +148,15 @@ class PackagesController < ApplicationController
   private
 
   # Send a dummy thumbnail reading "No screenshot available. Sorry."
-  # TODO: Make sure it uses X-Sendfile correctly in production
   def thumbnail404
-    send_file Rails.root.join('public/images/dummy/no-screenshots-available.png'),
+    send_file Rails.root.join('public/images/dummy/thumbnail404.png'),
+      type: "image/png",
+      disposition: 'inline',
+      status: 404
+  end
+
+  def screenshot404
+    send_file Rails.root.join('public/images/dummy/screenshot404.png'),
       type: "image/png",
       disposition: 'inline',
       status: 404

config/routes.rb

@@ -28,6 +28,8 @@ Debshots::Application.routes.draw do
   get 'about' => 'welcome#about'
   get 'thumbnail/:name' => 'packages#thumbnail', as: :thumbnail_image, name: /[^\/]+/
   get 'thumbnail-with-version/:name/:version' => 'packages#thumbnail', name: /[^\/]+/, version: /\S+/
+  get 'screenshot/:name' => 'packages#screenshot', as: :screenshot_image, name: /[^\/]+/
+  get 'screenshot-with-version/:name/:version' => 'packages#screenshot', name: /[^\/]+/, version: /\S+/
 
   # Legacy URLs
   get 'with_screenshots', to: redirect('/packages?show=with')