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rails--rails/railties/lib/rails/plugin.rb
Matthew Rudy Jacobs 319106d09c Metal can now line in plugins under app/metal [#2045 state:committed]
Signed-off-by: David Heinemeier Hansson <david@loudthinking.com>
2009-02-27 14:37:11 +01:00

167 lines
4.4 KiB
Ruby

module Rails
# The Plugin class should be an object which provides the following methods:
#
# * +name+ - Used during initialisation to order the plugin (based on name and
# the contents of <tt>config.plugins</tt>).
# * +valid?+ - Returns true if this plugin can be loaded.
# * +load_paths+ - Each path within the returned array will be added to the <tt>$LOAD_PATH</tt>.
# * +load+ - Finally 'load' the plugin.
#
# These methods are expected by the Rails::Plugin::Locator and Rails::Plugin::Loader classes.
# The default implementation returns the <tt>lib</tt> directory as its <tt>load_paths</tt>,
# and evaluates <tt>init.rb</tt> when <tt>load</tt> is called.
#
# You can also inspect the about.yml data programmatically:
#
# plugin = Rails::Plugin.new(path_to_my_plugin)
# plugin.about["author"] # => "James Adam"
# plugin.about["url"] # => "http://interblah.net"
class Plugin
include Comparable
attr_reader :directory, :name
def initialize(directory)
@directory = directory
@name = File.basename(@directory) rescue nil
@loaded = false
end
def valid?
File.directory?(directory) && (has_app_directory? || has_lib_directory? || has_init_file?)
end
# Returns a list of paths this plugin wishes to make available in <tt>$LOAD_PATH</tt>.
def load_paths
report_nonexistant_or_empty_plugin! unless valid?
returning [] do |load_paths|
load_paths << lib_path if has_lib_directory?
load_paths << app_paths if has_app_directory?
end.flatten
end
# Evaluates a plugin's init.rb file.
def load(initializer)
return if loaded?
report_nonexistant_or_empty_plugin! unless valid?
evaluate_init_rb(initializer)
@loaded = true
end
def loaded?
@loaded
end
def <=>(other_plugin)
name <=> other_plugin.name
end
def about
@about ||= load_about_information
end
# Engines are plugins with an app/ directory.
def engine?
has_app_directory?
end
# Returns true if the engine ships with a routing file
def routed?
File.exist?(routing_file)
end
def view_path
File.join(directory, 'app', 'views')
end
def controller_path
File.join(directory, 'app', 'controllers')
end
def metal_path
File.join(directory, 'app', 'metal')
end
def routing_file
File.join(directory, 'config', 'routes.rb')
end
private
def load_about_information
about_yml_path = File.join(@directory, "about.yml")
parsed_yml = File.exist?(about_yml_path) ? YAML.load(File.read(about_yml_path)) : {}
parsed_yml || {}
rescue Exception
{}
end
def report_nonexistant_or_empty_plugin!
raise LoadError, "Can not find the plugin named: #{name}"
end
def app_paths
[ File.join(directory, 'app', 'models'), File.join(directory, 'app', 'helpers'), controller_path, metal_path ]
end
def lib_path
File.join(directory, 'lib')
end
def classic_init_path
File.join(directory, 'init.rb')
end
def gem_init_path
File.join(directory, 'rails', 'init.rb')
end
def init_path
File.file?(gem_init_path) ? gem_init_path : classic_init_path
end
def has_app_directory?
File.directory?(File.join(directory, 'app'))
end
def has_lib_directory?
File.directory?(lib_path)
end
def has_init_file?
File.file?(init_path)
end
def evaluate_init_rb(initializer)
if has_init_file?
silence_warnings do
# Allow plugins to reference the current configuration object
config = initializer.configuration
eval(IO.read(init_path), binding, init_path)
end
end
end
end
# This Plugin subclass represents a Gem plugin. Although RubyGems has already
# taken care of $LOAD_PATHs, it exposes its load_paths to add them
# to Dependencies.load_paths.
class GemPlugin < Plugin
# Initialize this plugin from a Gem::Specification.
def initialize(spec, gem)
directory = spec.full_gem_path
super(directory)
@name = spec.name
end
def init_path
File.join(directory, 'rails', 'init.rb')
end
end
end