rabl-rails/lib/rabl-fast-json/compiler.rb
2012-04-08 23:26:18 +02:00

168 lines
4.2 KiB
Ruby

module RablFastJson
#
# Class that will compile RABL source code into a hash
# representing data structure
#
class Compiler
include Helpers
def initialize
@glue_count = 0
end
#
# Compile from source code and return the CompiledTemplate
# created.
#
def compile_source(source)
@template = CompiledTemplate.new
instance_eval(source)
@template
end
#
# Same as compile_source but from a block
#
def compile_block(&block)
@template = {}
instance_eval(&block)
@template
end
#
# Sets the object to be used as the data for the template
# Example:
# object :@user
# object :@user, :root => :author
#
def object(data, options = {})
data, name = extract_data_and_name(data)
@template.data = data
@template.root_name = options[:root] || name
end
#
# Sets a collection to be used as data for the template
# Example:
# collection :@users
# collection :@users, :root => :morons
#
def collection(data, options = {})
object(data)
@template.root_name = options[:root] if root_given?(options)
end
#
# Includes the attribute or method in the output
# Example:
# attributes :id, :name
# attribute :email => :super_secret
#
def attribute(*args)
if args.first.is_a?(Hash)
args.first.each_pair { |k, v| @template[v] = k }
else
options = args.extract_options!
args.each { |name|
key = options[:as] || name
@template[key] = name
}
end
end
alias_method :attributes, :attribute
#
# Creates a child node to be included in the output.
# name_or data can be an object or collection or a method to call on the data. It
# accepts :root and :partial options.
# Notes that partial and blocks are not compatible
# Example:
# child(:@posts, :root => :posts) { attribute :id }
# child(:posts, :partial => 'posts/base')
#
def child(name_or_data, options = {}, &block)
data, name = extract_data_and_name(name_or_data)
name = options[:root] if root_given?(options)
if partial_given?(options)
template = Library.instance.get(options[:partial])
@template[name] = template.merge!(:_data => data)
else
_compile_sub_template(name, data, &block)
end
end
#
# Glues data from a child node to the output
# Example:
# glue(:@user) { attribute :name }
#
def glue(data, &block)
return unless block_given?
name = :"_glue#{@glue_count}"
@glue_count += 1
_compile_sub_template(name, data, &block)
end
#
# Creates an arbitrary node in the json output.
# It accepts :if option to create conditionnal nodes. The current data will
# be passed to the block so it is advised to use it instead of ivars.
# Example:
# node(:name) { |user| user.first_name + user.last_name }
# node(:role, if: ->(u) { !u.admin? }) { |u| u.role }
#
def node(name, options = {}, &block)
condition = options[:if]
if condition.present?
if condition.is_a?(Proc)
@template[name] = [condition, block]
else
@template[name] = block if condition
end
else
@template[name] = block
end
end
alias_method :code, :node
#
# Extends an existing rabl template
# Example:
# extends 'users/base'
#
def extends(path)
t = Library.instance.get(path)
@template.merge!(t.source)
end
protected
#
# Extract data root_name and root name
# Example:
# :@users -> [:@users, nil]
# :@users => :authors -> [:@users, :authors]
#
def extract_data_and_name(name_or_data)
case name_or_data
when Symbol
if name_or_data.to_s.start_with?('@')
[name_or_data, nil]
else
[name_or_data, name_or_data]
end
when Hash
name_or_data.first
else
name_or_data
end
end
def _compile_sub_template(name, data, &block) #:nodoc:
compiler = Compiler.new
template = compiler.compile_block(&block)
@template[name] = template.merge!(:_data => data)
end
end
end