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module Rabl
class Engine
include Helpers
include Partials
include Helpers::Escaper
# List of supported rendering formats
FORMATS = [:json, :xml, :plist, :bson, :msgpack]
# Constructs a new ejs engine based on given vars, handler and declarations
# Rabl::Engine.new("...source...", { :format => "xml", :root => true, :view_path => "/path/to/views" })
def initialize(source, options = {})
@_source = source
@_settings = {}
@_options = options
@_view_path = options[:view_path]
@_context_scope = options[:scope]
@_cache_read_on_render = true
end
def source=(source)
@_source = source
end
# Renders the representation based on source, object, context_scope and locals
# Rabl::Engine.new("...source...", { :format => "xml" }).apply(context_scope, { :foo => "bar", :object => @user })
def apply(context_scope, locals, &block)
set_instance_variables!(context_scope, locals)
reset_settings!
reset_options!
eval_source(locals, &block)
instance_exec(root_object, &block) if block_given?
self
end
# Renders the representation based on a previous apply
# Rabl::Engine.new("...source...", { :format => "xml" }).apply(context_scope, { :foo => "bar", :object => @user }).render
def render(context_scope = nil, locals = nil, &block)
apply(context_scope, locals, &block) if context_scope || locals || block
cache_results do
send("to_#{@_options[:format]}")
end
end
def cache_key
return unless defined?(@_cache_key)
@_full_cache_key ||= begin
cache_key = Array(@_cache_key) + [@_options[:root_name], @_options[:format]]
if digestor_available? && respond_to?(:lookup_context) && lookup_context
template = @_options[:template] || @virtual_path
digest = \
if Gem::Version.new(Rails.version) >= Gem::Version.new('4.1')
Digestor.digest(:name => template, :finder => lookup_context)
else
Digestor.digest(template, :rabl, lookup_context)
end
cache_key << digest
end
cache_key
end
end
# Returns a hash representation of the data object
# to_hash(:root => true, :child_root => true)
def to_hash(options = {})
options = @_options.merge(options)
data = root_object
options[:root_name] = determine_object_root(data, root_name, options[:root])
result = \
if is_object?(data) || !data # object @user
Builder.new(data, @_settings, options).to_hash
elsif is_collection?(data) # collection @users
MultiBuilder.new(data, @_settings, options).to_a
end
result = escape_output(result) if Rabl.configuration.escape_all_output
result
end
def to_dumpable(options = {})
options = {
:child_root => Rabl.configuration.include_child_root
}.merge(options)
result = to_hash(options)
result = { collection_root_name => result } if collection_root_name
result
end
# Returns a json representation of the data object
# to_json(:root => true)
def to_json(options = {})
options = { :root => Rabl.configuration.include_json_root }.merge(options)
result = to_dumpable(options)
format_json(result)
end
# Returns a msgpack representation of the data object
# to_msgpack(:root => true)
def to_msgpack(options = {})
options = { :root => Rabl.configuration.include_msgpack_root }.merge(options)
result = to_dumpable(options)
Rabl.configuration.msgpack_engine.pack(result)
end
alias_method :to_mpac, :to_msgpack
# Returns a plist representation of the data object
# to_plist(:root => true)
def to_plist(options = {})
options = { :root => Rabl.configuration.include_plist_root }.merge(options)
result = to_dumpable(options)
Rabl.configuration.plist_engine.dump(result)
end
# Returns an xml representation of the data object
# to_xml(:root => true)
def to_xml(options = {})
options = {
:root => (include_root = Rabl.configuration.include_xml_root),
:child_root => include_root && Rabl.configuration.include_child_root
}.merge(options)
xml_options = Rabl.configuration.default_xml_options.merge(:root => collection_root_name || root_name)
result = to_hash(options)
result.to_xml(xml_options)
end
# Returns a bson representation of the data object
# to_bson(:root => true)
def to_bson(options = {})
options = { :root => Rabl.configuration.include_bson_root }.merge(options)
result = to_dumpable(options)
if !collection_root_name && is_collection?(root_object) && root_object.is_a?(Array)
result = { root_name => result }
end
Rabl.configuration.bson_engine.serialize(result).to_s
end
# Sets the object to be used as the data source for this template
# object(@user)
# object @user => :person
# object @users
def object(template_data)
current_data = (@_locals[:object].nil? || template_data == false) ? template_data : @_locals[:object]
@_data_object = data_object(current_data)
@_root_name_data = template_data.is_a?(Hash) && !current_data.is_a?(Hash) ? template_data : current_data
@_root_name_data = @_root_name_data.values.first if @_root_name_data.is_a?(Hash)
# If we turn this around, `@_root_name_date ==` may trigger data to be loaded unnecessarily.
if false == @_root_name_data
@_object_root_name = false
@_collection_name = false
end
end
# Returns the current object that is the topic of this template
# Can be the collection or the object depending on topic assigned
# root_object => @user
def root_object
return @_data_object if defined?(@_data_object)
data = @_locals[:object].nil? ? default_object : @_locals[:object]
@_data_object = data_object(data)
end
def root_name
return @_data_name if defined?(@_data_name)
@_data_name = @_options[:object_root_name] || begin
data = defined?(@_root_name_data) ? @_root_name_data : (@_locals[:object].nil? ? root_object : @_locals[:object])
data_name(data)
end
end
# Sets the object as a collection casted to a simple array
# collection @users
# collection @users => :people
# collection @users, :root => :person
# collection @users, :object_root => :person
def collection(data, options = {})
@_collection_name = options[:root] if options[:root]
@_collection_name ||= data.values.first if data.is_a?(Hash)
@_object_root_name = options[:object_root] if options.has_key?(:object_root)
object(data_object(data) || [])
end
# Sets the cache key to be used by ActiveSupport::Cache.expand_cache_key
# cache @user # calls @user.cache_key
# cache ['rabl', @user] # calls @user.cache_key and prefixes with rabl/
# cache 'user' # explicit key of 'user'
# cache # uses the current item within a collection
# cache 'user', expires_in: 1.hour
# options is passed through to the cache store
def cache(key = nil, options = {})
key ||= root_object # if called but missing, use object
@_cache_key = key
@_cache_options = options
end
# Indicates an attribute or method should be included in the json output
# attribute :foo, :as => "bar"
# attribute :foo => :bar, :bar => :baz
# attribute :foo => :bar, :bar => :baz, :if => lambda { |r| r.foo }
def attribute(*args)
if args.first.is_a?(Hash) # :foo => :bar, :bar => :baz
attr_aliases = args.first.except(:if, :unless)
conditions = args.first.slice(:if, :unless)
attr_aliases.each do |key, as|
attribute(key, conditions.merge(:as => as))
end
else # array of attributes i.e :foo, :bar, :baz
options = args.extract_options!
args.each do |name|
@_settings[:attributes] << { :name => name, :options => options }
end
end
end
alias_method :attributes, :attribute
# Creates an arbitrary node that is included in the json output.
# node(:foo) { "bar" }
# node(:foo, :if => lambda { ... }) { "bar" }
def node(name = nil, options = {}, &block)
@_settings[:node] << { :name => name, :options => options, :block => block }
end
alias_method :code, :node
# Creates a child node that is included in json output
# child(@user) { attribute :full_name }
def child(data, options = {}, &block)
@_settings[:child] << { :data => data, :options => options, :block => block }
end
# Glues data from a child node to the json_output
# glue(@user) { attribute :full_name => :user_full_name }
def glue(data, options = {}, &block)
@_settings[:glue] << { :data => data, :options => options, :block => block }
end
# Extends an existing rabl template with additional attributes in the block
# extends("users/show", :object => @user) { attribute :full_name }
def extends(file, options = {}, &block)
options = { :view_path => options[:view_path] || view_path }.merge(options)
@_settings[:extends] << { :file => file, :options => options, :block => block }
end
# Includes a helper module with a RABL template
# helper ExampleHelper
def helper(*klasses)
klasses.each { |klass| self.class.__send__(:include, klass) }
end
alias_method :helpers, :helper
# Returns a hash representing the partial
# partial("users/show", :object => @user)
# options must have :object
# options can have :view_path, :child_root, :root
def partial(file, options = {}, &block)
engine = partial_as_engine(file, options, &block)
engine = engine.render if engine.is_a?(Engine)
engine
end
# Disables reading (but not writing) from the cache when rendering.
def cache_read_on_render=(read)
@_cache_read_on_render = read
end
def cache_read_on_render?
@_cache_read_on_render
end
protected
# Returns a guess at the default object for this template
# default_object => @user
def default_object
return unless context_scope.respond_to?(:controller)
controller_name = context_scope.controller.controller_name
stripped_name = controller_name.split(%r{::|\/}).last
ivar_object = instance_variable_get("@#{stripped_name}")
ivar_object if is_object?(ivar_object)
end
# Returns a guess at the format in this context_scope
# request_format => "xml"
def request_format
format = request_params[:format]
if format.nil? && context_scope.respond_to?(:request)
request = context_scope.request
format = request.format.to_sym.to_s if request.respond_to?(:format)
end
format = "json" unless format && respond_to?("to_#{format}")
format
end
# Returns the request parameters if available in the context_scope
# request_params => { :foo => "bar" }
def request_params
(context_scope.params if context_scope.respond_to?(:params)) || {}
end
# Returns data as json embraced with callback when detected
# format_json({ :foo => "bar" }) => "test({ foo : 'bar' })"
# format_json("{ foo : "bar" }") => "test({ foo : 'bar' })"
def format_json(json_output)
unless json_output.is_a?(String)
json_engine = Rabl.configuration.json_engine
json_output = if json_engine.respond_to?(:dump)
json_engine.dump(json_output)
else
json_engine.encode(json_output)
end
end
use_callback = Rabl.configuration.enable_json_callbacks && request_params[:callback].present?
json_output = "#{request_params[:callback]}(#{json_output})" if use_callback
json_output
end
# Augments respond to supporting context_scope methods
def respond_to?(name, include_private = false)
context_scope.respond_to?(name, include_private) || super
end
# Supports calling helpers defined for the template context_scope using method_missing hook
def method_missing(name, *args, &block)
context_scope.respond_to?(name, true) ? context_scope.__send__(name, *args, &block) : super
end
def copy_instance_variables_from(object, exclude = []) #:nodoc:
vars = object.instance_variables.map(&:to_s) - exclude.map(&:to_s)
vars.each { |name| instance_variable_set(name, object.instance_variable_get(name)) }
end
def reset_settings!
@_settings[:attributes] = []
@_settings[:node] = []
@_settings[:child] = []
@_settings[:glue] = []
@_settings[:extends] = []
end
# Resets the options parsed from a rabl template.
def reset_options!
@_options[:root_name] = nil
@_options[:read_multi] = false
@_options[:scope] = context_scope
end
# Caches the results of the block based on object cache_key
# cache_results { compile_hash(options) }
def cache_results(&block)
return yield unless template_cache_configured? && defined?(@_cache_key)
if cache_read_on_render?
fetch_result_from_cache(cache_key, @_cache_options, &block)
else
write_result_to_cache(cache_key, @_cache_options, &block)
end
end
def digestor_available?
defined?(Rails) && Rails.version =~ /^[45]/
end
def set_instance_variables!(context_scope, locals)
@_context_scope = context_scope
@_locals = locals || {}
copy_instance_variables_from(context_scope, [:@assigns, :@helpers])
@_options[:format] ||= request_format
set_locals(@_locals)
end
def set_locals(locals)
locals.merge!(locals.delete(:locals) || {})
locals.each { |key, value| instance_variable_set(:"@#{key}", value) }
end
def eval_source(locals, &block)
# Note: locals and block may be used by the eval'ed source
return unless @_source.present?
if @_options[:source_location]
instance_eval(@_source, @_options[:source_location])
else
instance_eval(@_source)
end
end
end
end
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