middleman/middleman-core/lib/middleman-core/configuration.rb
2013-05-23 14:55:26 -07:00

236 lines
7 KiB
Ruby

module Middleman
module Configuration
# Access to a global configuration manager for the whole Middleman project,
# plus backwards compatibility mechanisms for older Middleman projects.
module Global
def self.included(app)
app.send :extend, ClassMethods
end
module ClassMethods
# Global configuration for the whole Middleman project.
# @return [ConfigurationManager]
def config
@_config ||= ConfigurationManager.new
end
# Set attributes (global variables)
#
# @deprecated Prefer accessing settings through "config".
#
# @param [Symbol] key Name of the attribue
# @param default Attribute value
# @return [void]
def set(key, default=nil, &block)
config.define_setting(key, default)
@inst.set(key, default, &block) if @inst
end
# Access global settings as methods, to preserve compatibility with
# old Middleman.
#
# @deprecated Prefer accessing settings through "config".
def method_missing(method, *args)
if config.defines_setting? method
config[method]
else
super
end
end
# Needed so that method_missing makes sense
def respond_to?(method, include_private = false)
super || config.defines_setting?(method)
end
end
def config
self.class.config
end
# Backwards compatibilty with old Sinatra template interface
#
# @deprecated Prefer accessing settings through "config".
#
# @return [ConfigurationManager]
alias :settings :config
# Set attributes (global variables)
#
# @deprecated Prefer accessing settings through "config".
#
# @param [Symbol] key Name of the attribue
# @param value Attribute value
# @return [void]
def set(key, value=nil, &block)
value = block if block_given?
config[key] = value
end
# Access global settings as methods, to preserve compatibility with
# old Middleman.
#
# @deprecated Prefer accessing settings through "config".
def method_missing(method, *args)
if config.defines_setting? method
config[method]
else
super
end
end
# Needed so that method_missing makes sense
def respond_to?(method, include_private = false)
super || config.defines_setting?(method)
end
end
# A class that manages a collection of documented settings.
# Can be used by extensions as well as the main Middleman
# application. Extensions should probably finalize their instance
# after defining all the settings they want to expose.
class ConfigurationManager
def initialize
# A hash from setting key to ConfigSetting instance.
@settings = {}
@finalized = false
end
# Get all settings, sorted by key, as ConfigSetting objects.
# @return [Array<ConfigSetting>]
def all_settings
@settings.values.sort_by(&:key)
end
# Get a full ConfigSetting object for the setting with the give key.
# @return [ConfigSetting]
def setting(key)
@settings[key]
end
# Get the value of a setting by key. Returns nil if there is no such setting.
# @return [Object]
def [](key)
setting = @settings[key]
setting ? setting.value : nil
end
# Set the value of a setting by key. Creates the setting if it doesn't exist.
# @param [Symbol] key
# @param [Object] val
def []=(key, val)
setting = @settings[key] || define_setting(key)
setting.value = val
end
# Allow configuration settings to be read and written via methods
def method_missing(method, *args)
if defines_setting?(method) && args.size == 0
self[method]
elsif method.to_s =~ /^(\w+)=$/ && args.size == 1
self[$1.to_sym] = args[0]
else
super
end
end
# Needed so that method_missing makes sense
def respond_to?(method, include_private = false)
super || defines_setting?(method) || (method =~ /^(\w+)=$/ && defines_setting?($1))
end
# Does this configuration manager know about the setting identified by key?
# @param [Symbol] key
# @return [Boolean]
def defines_setting?(key)
@settings.has_key?(key)
end
# Define a new setting, with optional default and user-friendly description.
# Once the configuration manager is finalized, no new settings may be defined.
#
# @param [Symbol] key
# @param [Object] default
# @param [String] description
# @return [ConfigSetting]
def define_setting(key, default=nil, description=nil)
raise "Setting #{key} doesn't exist" if @finalized
raise "Setting #{key} already defined" if @settings.has_key?(key)
raise "Setting key must be a Symbol" unless key.is_a? Symbol
@settings[key] = ConfigSetting.new(key, default, description)
end
# Switch the configuration manager is finalized, it switches to read-only
# mode and no new settings may be defined.
def finalize!
@finalized = true
self
end
# Deep duplicate of the configuration manager
def dup
ConfigurationManager.new.tap {|c| c.load_settings(self.all_settings) }
end
# Load in a list of settings
def load_settings(other_settings)
other_settings.each do |setting|
new_setting = define_setting(setting.key, setting.default, setting.description)
new_setting.value = setting.value if setting.value_set?
end
end
def to_h
hash = {}
@settings.each do |key, setting|
hash[key] = setting.value
end
hash
end
def to_s
to_h.inspect
end
end
# An individual configuration setting, with an optional default and description.
# Also models whether or not a value has been set.
class ConfigSetting
# The name of this setting
attr_accessor :key
# The default value for this setting
attr_accessor :default
# A human-friendly description of the setting
attr_accessor :description
def initialize(key, default, description)
@value_set = false
self.key = key
self.default = default
self.description = description
end
# The user-supplied value for this setting, overriding the default
def value=(value)
@value = value
@value_set = true
end
# The effective value of the setting, which may be the default
# if the user has not set a value themselves. Note that even if the
# user sets the value to nil it will override the default.
def value
value_set? ? @value : default
end
# Whether or not there has been a value set beyond the default
def value_set?
@value_set
end
end
end
end