Expire pages that want file, when file is successfully uploaded

Reported by Andrew Stacey

app/controllers/file_controller.rb

@@ -18,6 +18,9 @@ class FileController < ApplicationController
       new_file = @web.wiki_files.create(params['file'])
       if new_file.valid?
         flash[:info] = "File '#{@file_name}' successfully uploaded"
+        WikiReference.pages_that_want_file(@web, @file_name).each do |page|
+          RevisionSweeper.expire_page(page)
+        end
         redirect_to(params['referring_page'])
       else
         # pass the file with errors back into the form

app/controllers/revision_sweeper.rb

@@ -25,6 +25,10 @@ class RevisionSweeper < ActionController::Caching::Sweeper
     end
   end
   
+  def self.expire_page(page)
+    new.expire_caches(page)
+  end
+
   private
   
   def expire_caches(page)

app/models/wiki_reference.rb

@@ -51,6 +51,15 @@ class WikiReference < ActiveRecord::Base
     names = connection.select_all(sanitize_sql([query, file_name])).map { |row| row['name'] }
   end
   
+  def self.pages_that_want_file(web, file_name)
+    query = 'SELECT name FROM pages JOIN wiki_references ' +
+      'ON pages.id = wiki_references.page_id ' +
+      'WHERE wiki_references.referenced_name = ? ' +
+      "AND wiki_references.link_type in ('#{WANTED_FILE}') " +
+      "AND pages.web_id = '#{web.id}'"
+    names = connection.select_all(sanitize_sql([query, file_name])).map { |row| row['name'] }
+  end
+
   def self.pages_that_include(web, page_name)
     query = 'SELECT name FROM pages JOIN wiki_references ' +
       'ON pages.id = wiki_references.page_id ' +