mankind · August 17, 2011 12:07 · May 27, 2011
diff --git a/ImageUploader b/ImageUploader
@@ -0,0 +1,74 @@
+require 'carrierwave/processing/mini_magick'
+
+class ImageUploader < CarrierWave::Uploader::Base
+  include CarrierWave::MiniMagick
+
+  IMAGE_EXTENSIONS = %w(jpg jpeg gif png)
+  DOCUMENT_EXTENSIONS = %w(exe pdf doc docm xls)
+
+  def store_dir
+    "files/#{model.id}"
+  end
+
+  def cache_dir
+    "#{::Rails.root.to_s}/tmp/uploads" 
+  end
+
+  def extension_white_list
+    IMAGE_EXTENSIONS + DOCUMENT_EXTENSIONS
+  end
+
+  def default_url
+    "/images/fallback/" + [version_name, "default.png"].compact.join('_')
+  end
+
+  # create a new "process_extensions" method.  It is like "process", except
+  # it takes an array of extensions as the first parameter, and registers
+  # a trampoline method which checks the extension before invocation
+  def self.process_extensions(*args)
+    extensions = args.shift
+    args.each do |arg|
+      if arg.is_a?(Hash)
+        arg.each do |method, args|
+          processors.push([:process_trampoline, [extensions, method, args]])
+        end
+      else
+        processors.push([:process_trampoline, [extensions, arg, []]])
+      end
+    end
+  end
+
+  # our trampoline method which only performs processing if the extension matches
+  def process_trampoline(extensions, method, args)
+    extension = File.extname(original_filename).downcase
+    extension = extension[1..-1] if extension[0,1] == '.'
+    self.send(method, *args) if extensions.include?(extension)
+  end
+
+  # version actually defines a class method with the given block
+  # therefore this code does not run in the context of an object instance  
+  # and we cannot access uploader instance fields from this block
+  version :top do
+    process_extensions ImageUploader::IMAGE_EXTENSIONS, :resize_to_fit => [910,1800]
+  end
+
+  version :logo do
+    process_extensions ImageUploader::IMAGE_EXTENSIONS, :resize_to_fit => [210,100]
+  end
+
+  version :gallery do
+    process_extensions ImageUploader::IMAGE_EXTENSIONS, :resize_to_fill => [152,114]
+  end
+
+  version :side do
+    process_extensions ImageUploader::IMAGE_EXTENSIONS, :resize_to_fit => [455,1800]
+  end
+
+  version :preview do
+    process_extensions ImageUploader::IMAGE_EXTENSIONS, :resize_to_fit => [120, 1800]
+  end
+
+  version :thumb do
+    process_extensions ImageUploader::IMAGE_EXTENSIONS, :resize_to_fill => [35, 35]
+  end
+end