AppConfig

AppConfig is a library to manage your (web) application dynamic settings with flexible access and configuration strategy.

Primary datasource for AppConfig is an ActiveRecord model.

Installation

via rubygems:

gem install app-config

via github:

git clone git://github.com/sosedoff/app-config.git
cd app-config
gem build
gem install app-config-x.y.z.gem

Supported platforms

Ruby 1.8.7
Ruby EE 1.8.7
Ruby 1.9.2

Data Formats

You can use following formats:

String
Boolean
Array
Hash

String format is a default format. Everything is a string by default.

Boolean format is just a flag, values 'true', 'on', 'yes', 'y', '1' are equal to True. Everything else is False.

Array format is a multiline text which is transformed into array. Each evelemnt will be trimmed. Empty strings are ignored.

Hash format is special key-value string, "foo: bar, user: username", which is transformed into Hash instance. Only format "keyname: value, keyname2: value2" is supported. No nested hashes allowed.

Usage

AppConfig is designed to work with ActiveRecord model. Only ActiveRecord >= 3.0.0 is supported.

By default model "Setting" will be used as a data source.

Setup

In order to use AppConfig you should have a source table, similar to this:

class CreateSettings < ActiveRecord::Migration
  def self.up
    create_table :settings do |t|
      t.string   :keyname,       :null => false, :limit => 64
      t.text     :value,         :null => false
      t.string   :value_format,  :limit => 64,   :default => "string"
      t.string   :name,          :limit => 64
      t.string   :description,   :limit => 512
      t.timestamps
    end
  end

  def self.down
    drop_table :settings
  end
end

Required columns are:

keyname
value
value_format

Columns :name and :description are optional and used only for informative purpose (ex: show name and description in admin panel).

There is no need in indexes since the data is being loaded only once on application start.

Simple model with validations should look like this:

class Setting < ActiveRecord::Base
  validates_presence_of   :keyname, :value
  validates_uniqueness_of :keyname
end

Configuration

Default configuration method is:

AppConfig.configure

If your settings model has a different schema, you can redefine columns:

AppConfig.configure(
  :model  => Setting,           # model class name as source
  :key    => 'KEYNAME_FIELD',   # field that contains name
  :format => 'FORMAT_FIELD',    # field that contains key format
  :value  => 'VALUE_FIELD',     # field that contains value data
)

Load all settings somewhere in your application. In Rails it should be initializer file.

AppConfig.load

Configuration in Rails 3: (you can put this into environment/ENV or application.rb) Make sure your application does not have any critical parts depending on AppConfig at startup.

config.after_initialize do
  AppConfig.configure(:model => Setting)
  AppConfig.load if Setting.table_exists?
end

AppConfig gives you 3 ways to access variables:

AppConfig.my_setting      # method-like
AppConfig[:my_setting]    # hash-like by symbol key
AppConfig['my_setting']   # hash-like by string key

You can define settings items manually. NOTE: THESE KEYS WILL BE REMOVED ON RELOAD/LOAD.

AppConfig.set_key('KEYNAME', 'VALUE', 'FORMAT')

Everytime you change your settings on the fly, use reload:

AppConfig.reload

Cleanup everything:

AppConfig.flush