Homeland::ImageThumb 支持 HTTP Request Headers Pragma: no-cache

Author: huacnlee

app/controllers/home_controller.rb

@@ -12,7 +12,8 @@ def uploads
     # DO NOT use this in production environment.
     format, version = params[:format].split("!")
     filename = [params[:path], format].join(".")
-    thumb = Homeland::ImageThumb.new(filename, version)
+    pragma = request.headers['Pragma'] == 'no-cache'
+    thumb = Homeland::ImageThumb.new(filename, version, pragma: pragma)
     send_file thumb.outpath, type: 'image/jpeg', disposition: 'inline'
   end
 

lib/homeland/image_thumb.rb

@@ -8,12 +8,13 @@ class ImageThumb
     attr_reader :filename
     attr_reader :version
 
-    def initialize(filename, version)
+    def initialize(filename, version, pragma: false)
       @filename = filename
       @version = version
       @outpath = Rails.root.join('tmp', 'cache', 'uploads-thumb', "#{filename}-#{version}")
 
-      generate! unless File.exists? outpath
+      notfound = !File.exists?(outpath)
+      generate! if pragma || notfound
     end
 
     private