# Configurability 1.0.0 **URL:** \ **Category:** Ruby\ **Created:** [July 13, 2010, 1:20am UTC](https://www.ruby-forum.com/t/configurability-1-0-0/191459 "2010-07-13T01:20:28Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![mgreenly](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/85f322/32.png) [@mgreenly](https://www.ruby-forum.com/u/mgreenly)\ **Post date:** [July 13, 2010, 1:20am UTC](https://www.ruby-forum.com/t/configurability-1-0-0/191459/1 "2010-07-13T01:20:28Z")
Version 1.0.0 of configurability has been released. Configurability is a mixin that allows you to add configurability to one or more objects or classes. You can assign them each a subsection of the configuration, and then later, when the configuration is loaded, the configuration is split up and sent to the objects that will use it. ## Usage To add configurability to a class, just require the library and extend the class: ``` class User extend Configurability end ``` Or, add it to a instance: ``` user = User.new user.extend( Configurability ) ``` Later, when you’ve loaded the configuration, can can call ``` Configurability.configure_objects( config ) ``` and the `config` will be spliced up and sent to all the objects that have been extended with it. `Configurability` expects the configuration to be broken up into a number of sections, each of which is accessible via either a method with the _section name_ or the index operator (`#[]`) that takes the _section name_ as a `Symbol` or a `String`: ``` config.section_name config[:section_name] config['section_name'] ``` The section name is based on an object’s _config key_, which is the name of the object that is being extended with all non-word characters converted into underscores (`_`) by default. It will also have any leading Ruby-style namespaces stripped, e.g., ``` MyClass -> :myclass Acme::User -> :user "J. Random Hacker" -> :j_random_hacker ``` If the object responds to the `#name` method, then the return value of that method is used to derive the name. If it doesn’t have a `#name` method, the name of its `Class` will be used instead. If its class is anonymous, then the object’s config key will be `:anonymous`. When the configuration is loaded, an instance variable called `@config` is set to the appropriate section of the config object for each object that has been extended with Configurability. ## Customization The default behavior above is just provided as a reasonable default; it is expected that you’ll want to customize at least one or two things about how configuration is handled in your objects. ### Setting a Custom Config Key The first thing you might want to do is change the config section that corresponds to your object. You can do that by declaring a different config key, either using a declarative method: ``` class OutputFormatter extend Configurability config_key :format end ``` or by overriding the `#config_key` method and returning the desired value as a Symbol: ``` class User extend Configurability def self::config_key return :employees end end ``` ### Changing How an Object Is Configured You can also change what happens when an object is configured by implementing a `#configure` method that takes the config section as an argument: ``` class WebServer extend Configurability def self::configure( configsection ) @default_bind_addr = configsection[:host] @default_port = configsection[:port] end end ``` If you still want the `config` variable to be set, just `super` from your implementation; don’t if you don’t want it to be set. ## Installation Via gems: $ sudo gem install configurability or from source: $ wget [http://deveiate.org/code/configurability-1.0.0.tar.gz](http://deveiate.org/code/configurability-1.0.0.tar.gz) $ tar -xzvf configurability-1.0.0.tar.gz $ cd configurability-1.0.0 $ sudo rake install ## Changes This is the first release. ## Development You can submit bug reports, suggestions, and read more about future plans at the project page: > [http://bitbucket.org/ged/configurability](http://bitbucket.org/ged/configurability) or clone it with Mercurial from the same address. ## License Copyright (c) 2010, Michael G. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. - Neither the name of the author/s, nor the names of the project’s contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ---
**Author:** ![mgreenly](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/85f322/32.png) [@mgreenly](https://www.ruby-forum.com/u/mgreenly)\ **Post date:** [July 14, 2010, 5:24am UTC](https://www.ruby-forum.com/t/configurability-1-0-0/191459/2 "2010-07-14T05:24:49Z")
On Monday, July 12, 2010 06:20:15 pm Michael G. wrote: > It will also have any leading > Ruby-style namespaces stripped, e.g., > > ``` > Acme::User -> :user > > ``` What’s the rationale for stripping namespaces? It looks like hashes are supported, so the above could be configured with something like: Configurability.configure\_objects({ :user =\> {:foo =\> ‘bar’}, … }) It seems to me that I’d want something more like this: Configurability.configure\_objects({ :acme =\> { :user =\> {:foo =\> ‘bar’} }, … }) Especially since the whole point of namespacing things is to avoid naming conflicts, so I could conceivably have: Configurability.configure\_objects({ :acme =\> { :user = {:foo =\> ‘bar’}, :anvil =\> { :user =\> ‘Wile E. Coyote’ } }, :examplecorp =\> { :user =\> {:something =\> ‘else’} } }) It looks like I could still do something like that by overriding the config key, but that would flatten it to: Configurability.configure\_objects({ :acme\_user =\> {:foo =\> ‘bar’}, :acme\_anvil =\> {:user =\> ‘Wile E. Coyote’}, :examplecorp\_user =\> {:something =\> ‘else’} })