Adding automatic datestamping to generated sprite background image urls. This allows cache expiration on every release

Author: merbjedi

README.md

@@ -79,7 +79,8 @@ Configuration of `sprite` is done via `config/sprite.yml`. It allows you to set
   - `default_format:` defines the default file image format of the generated files. (defaults to `png`)
   - `default_spacing:` defines the default pixel spacing between sprites (defaults to 0)
   - `class_separator:` used to generated the class name by separating the image name and sprite name (defaults to `-`)
-
+  - `add_datestamps`: whether or not to add datestamps to the generated background image urls. this will allow proper cache versioning (defaults to `true`)
+  
 * `images:` section provides an array of configurations which define which image files are built, and where they get their sprites from. each image setup provides the following config options:
   - `name:` name of image (required)
   - `sources:` defines a list of source image filenames to build the target image from (required). They are parsed by <code>Dir.glob</code>

VERSION

@@ -1 +1 @@
-0.1.6
+0.1.7

lib/sprite/builder.rb

@@ -30,6 +30,9 @@ def initialize(config = nil, images = nil)
       @images = images || []
       set_image_defaults
       expand_image_paths
+
+      # initialize datestamp
+      @datestamp_query = "?#{Time.now.to_i}" if @config["add_datestamps"]
 
       # initialize sprite files
       @sprite_files = {}
@@ -86,7 +89,7 @@ def write_image(image)
 
       # write sprite image file to disk
       dest_image.write(path)
-      @sprite_files["#{name}.#{format}"] = results
+      @sprite_files["#{name}.#{format}#{@datestamp_query}"] = results
     end
 
     def write_styles
@@ -111,6 +114,10 @@ def set_config_defaults
       @config['class_separator']    ||= '-'
       @config["sprites_class"]      ||= 'sprites'
       @config["default_spacing"]    ||= 0
+      
+      unless @config.has_key?("add_datestamps")
+        @config["add_datestamps"] = true
+      end
     end
 
     # if no image configs are detected, set some intelligent defaults