Class: Yacl::Loader::YamlFile

Inherits:
Yacl::Loader show all
Defined in:
lib/yacl/loader/yaml_file.rb

Overview

YamlFile loads a Properites instance from a single yaml file.

Examples:

yd = YamlFile.new( :filename => "./config/database.yml" )
props = yd.properties
props.adapter #=> 'postgres'

You may also create a YamlFile and have it use the propety from a Properites instance to indicate the directory to load from.

other_props.config.file # => ./config/database.yml

yd = YamFile.new( :properties => other_props, :parameter => 'config.file' )

props = yd.properties
props.adapter # => postgre

Defined Under Namespace

Classes: Error

Instance Attribute Summary

Attributes inherited from Yacl::Loader

#options

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Yacl::Loader

extract_path, mapify_key, #reference_properties

Constructor Details

#initialize(opts = {}) ⇒ YamlFile

Returns a new instance of YamlFile.



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# File 'lib/yacl/loader/yaml_file.rb', line 24

def initialize( opts = {} )
  super
  @path      = YamlFile.extract_path( options )
  @scope     = options.fetch( :scope, nil )
  @parameter = YamlFile.mapify_key( options[:parameter] )

  if (not @path) and (reference_properties and @parameter) then
    @path = Pathname.new( reference_properties.get( *@parameter ) )
  end


  YamlFile.validate_file( @path )
end

Class Method Details

.load_properties(filename, scope) ⇒ Object

Internal: load a Properties from the given filename.

filename - The name of the yaml file to load scope - scope the loaded Properties by the given scope

Returns a Properties instance.

Raises:



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# File 'lib/yacl/loader/yaml_file.rb', line 77

def load_properties( filename, scope )
  loaded = ::YAML.load_file( filename )
  raise Error, "#{filename} does not contain a top level hash" unless loaded.kind_of?( Hash )

  p = Yacl::Properties.new( loaded )
  return scoped( p, scope, filename )
end

.scoped(p, scope, filename) ⇒ Object

Internal: scope the given Properties that are loaded from the given filename.

p - The Properties to scope by scope scope - The scope to apply to p filename - The filename from which Properties was loaded

Raises Error if the scope does not exist

Returns a new Properties instance.

Raises:



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# File 'lib/yacl/loader/yaml_file.rb', line 95

def scoped( p, scope, filename )
  return p unless scope
  raise Error, "#{filename} does not contain a top level scope of '#{scope}'. Options are #{p.scopes.join(", ")}" unless p.has_scope?( scope )
  return p.scoped_by( scope )
end

.validate_and_load_properties(filename, scope = nil) ⇒ Object

Internal: load a Properties from the given filename.

filename - The name of the yaml file to load scope - scope the loaded Properties by the given scope

Returns a Properties instance.



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# File 'lib/yacl/loader/yaml_file.rb', line 49

def validate_and_load_properties( filename, scope = nil )
  validate_file( filename )
  YamlFile.load_properties( filename, scope )
end

.validate_file(path) ⇒ Object

Internal: Validate that the give Pathname is a valid, readable file

path - the Patname we are going to check

Validates:

1) that path has a value 1) that the path exists 2) that the path is readable

Raises an error if either of the above failes

Raises:



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# File 'lib/yacl/loader/yaml_file.rb', line 65

def validate_file( path )
  raise Error, "No path specified" unless path
  raise Error, "#{path} does not exist" unless path.exist?
  raise Error, "#{path} is not readable" unless path.readable?
end

Instance Method Details

#properties ⇒ Object 



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# File 'lib/yacl/loader/yaml_file.rb', line 38

def properties
  YamlFile.validate_and_load_properties( @path, @scope )
end