Class: Configit::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/configit/base.rb

Overview

The base class the custom configuration classes should derive from.

Example

class FooConfig < Configit::Base
  attribute :name, "The name of the user", :required => true
  attribute :port, :required => true, :type => :integer, :default => 80
  attribute :log_level, :type => :symbol, :default => :debug
end

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.attribute(name, desc = nil, options = {}) ⇒ Object

Defines a new attribute on the config.

The first argument should be the name of the attribute.

If the next argument is a string it will be interpreted as the description of the argument.

The last argument should be a valid options hash.

Valid options

:required

Determines if the option is required or not. Should be either true or false

:type

The type of the attribute. Should be one of :integer, :string :symbol, :float

Raises:



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# File 'lib/configit/base.rb', line 131

def attribute(name, desc=nil, options={})
  raise AttributeAlreadyDefined, name if schema.has_key? name
  
  if options == {} && Hash === desc
    options = desc
    desc = nil
  end

  attr = AttributeDefinition.new(name, desc, options)
  schema[name] = attr


  @attribute_module ||= begin
    m = Module.new 
    include m
    m
  end

  @attribute_module.class_eval do
    define_method name do
      value = attributes[name] || attr.default
      if value != nil
        @@converters[attr.type].call(value)
      else
        value
      end
    end

    define_method "#{name}=" do |value| 
      attributes[name] = value
      value
    end
  end

  return attr
end

.evaluate_erb=(value) ⇒ Object

Raises:



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# File 'lib/configit/base.rb', line 72

def evaluate_erb=(value)
  raise ArgumentError unless value == true || value == false
  @evaluate_erb = value
end

.load_from_file(filename) ⇒ Object

Load the config from a file.

Raises:



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# File 'lib/configit/base.rb', line 91

def load_from_file(filename)
  raise ArgumentError, "File #{filename} does not exist"  unless File.exists?(filename)
  raise ArgumentError, "File #{filename} is not readable" unless File.readable?(filename)

  return load_from_string(IO.read(filename))
end

.load_from_file!(filename) ⇒ Object

Same as load_from_file except it will raise an ArgumentError if the config is not valid.



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# File 'lib/configit/base.rb', line 108

def load_from_file!(filename)
  config = load_from_file(filename)
  config.ensure_valid!
  config
end

.load_from_string(string) ⇒ Object

Loads the config from a YAML string.

Unrecognized attributes are placed into the errors list.



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# File 'lib/configit/base.rb', line 80

def load_from_string(string)
  config = self.new
  string = ERB.new(string).result unless @evaluate_erb == false
  (YAML.load(string) || {}).each do |key,value|
    key = key.to_sym
    config.attributes[key] = value
  end
  return config
end

.load_from_string!(string) ⇒ Object

Same as load_from_string except it will raise an ArgumentError if the config is not valid



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# File 'lib/configit/base.rb', line 100

def load_from_string!(string)
  config = load_from_string(string)
  config.ensure_valid!
  config
end

.schema ⇒ Object

Returns a hash of Configit::AttributeDefinition’s keyed by attribute name.



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# File 'lib/configit/base.rb', line 68

def schema
  @schema ||= {}
end

Instance Method Details

#attributes ⇒ Object

Returns the attributes defined for this class.



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# File 'lib/configit/base.rb', line 24

def attributes
  @attributes ||= {}
end

#clear_errors ⇒ Object 



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# File 'lib/configit/base.rb', line 32

def clear_errors
  @errors = []
end

#ensure_valid! ⇒ Object 



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# File 'lib/configit/base.rb', line 36

def ensure_valid!
  if !valid?
    message = "#{self.class.name} config invalid. #{self.errors.first}"
    raise ArgumentError, message
  end
  true
end

#errors ⇒ Object 



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# File 'lib/configit/base.rb', line 28

def errors
  @errors ||= []
end

#schema ⇒ Object 



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# File 'lib/configit/base.rb', line 62

def schema
  self.class.schema
end

#valid? ⇒ Boolean

Returns true if there are no errors, false otherwise

Returns:

  • (Boolean) 


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# File 'lib/configit/base.rb', line 45

def valid?
  clear_errors

  unknown_attributes = attributes.keys - schema.keys
  unknown_attributes.each do |key|
    errors << "#{key} is not a valid attribute name"
  end

  schema.values.each do |attribute|
    if error = attribute.validate(attributes[attribute.name])
      errors << error
    end
  end
  
  errors.empty?
end