Configurable

This is just a simple module which provides an object with a nice API for configuring it.

The best explanation is with an example. Here we configure the ImageProcessor class.

First declare which attributes we want to be configurable.

class ImageProcessor

  extend Configurable
  
  configurable_attr :processing_lib         # defaults to nil
  configurable_attr :default_format, 'png'  # defaults to 'png'

  # ...other stuff...

end

Then we can configure them as we need

ImageProcessor.configure do |c|
  c.processing_lib = 'imagemagick'
end

Note that we can NOT configure the ImageProcessor by just saying ImageProcessor.processing_lib = 'imagemagick', the only way is via the configure method.

We can see what the configuration is at any time like so:

ImageProcessor.configuration   # {:processing_lib => 'imagemagick', :default_format => 'png'}

Why not just use attr_accessors?

It's more of a conceptual win really. By limiting the configuration of these attributes to the configure method, the user knows that they are dealing with the configuration of the object. Also we are able to view the configuration with ImageProcessor.configuration because we've kept them separate from other accessor methods.

Why not just use a ImageProcessor.config hash?

Because after configuring an object, the rest of the code shouldn't care whether an attribute had to be configured or not (whereas it would using ImageProcessor.config[:processing_lib]). This way we can decide later that an attribute should actually be configurable, and this is transparent to the rest of the code.

Install

Usual way for github gems.

Copyright

Copyright (c) 2009 Mark Evans. See LICENSE for details.