Move trace pictures/icons into their own controllers

app/controllers/traces/icons_controller.rb

@@ -0,0 +1,29 @@
+module Traces
+  class IconsController < ApplicationController
+    before_action :authorize_web
+    before_action :check_database_readable
+
+    authorize_resource :trace
+
+    def show
+      trace = Trace.find(params[:trace_id])
+
+      if trace.visible? && trace.inserted?
+        if trace.public? || (current_user && current_user == trace.user)
+          if trace.icon.attached?
+            redirect_to rails_blob_path(trace.icon, :disposition => "inline")
+          else
+            expires_in 7.days, :private => !trace.public?, :public => trace.public?
+            send_file(trace.icon_picture_name, :filename => "#{trace.id}_icon.gif", :type => "image/gif", :disposition => "inline")
+          end
+        else
+          head :forbidden
+        end
+      else
+        head :not_found
+      end
+    rescue ActiveRecord::RecordNotFound
+      head :not_found
+    end
+  end
+end