require 'hanami/view/rendering/registry'
require 'hanami/view/rendering/scope'
require 'hanami/view/rendering/null_local'
module Hanami
module View
# Rendering methods
#
# @since 0.1.0
#
# @see Hanami::View::Rendering::InstanceMethods
module Rendering
# @since 0.1.0
# @api private
def self.extended(base)
base.class_eval do
include InstanceMethods
end
end
module InstanceMethods
# Initialize a view
#
# @param template [Hanami::View::Template] the template to render
# @param locals [Hash] a set of objects available during the rendering
# process.
#
# @since 0.1.0
#
# @see Hanami::View::Template
#
# @example
# require 'hanami/view'
#
# class IndexView
# include Hanami::View
# end
#
# template = Hanami::View::Template.new('index.html.erb')
# view = IndexView.new(template, {article: article})
def initialize(template, **locals)
@template = template
@locals = locals
@scope = Scope.new(self, @locals)
end
# Render the template by bounding the local scope.
# If it uses a layout, it renders the template first and then the
# control passes to the layout.
#
# Override this method for custom rendering policies.
# For instance, when a serializer is used and there isn't the need of
# a template.
#
# @return [String] the output of the rendering process
#
# @raise [Hanami::View::MissingTemplateError] if the template is nil
#
# @since 0.1.0
#
# @see Hanami::View::Layout
#
# @example with template
# require 'hanami/view'
#
# class IndexView
# include Hanami::View
# end
#
# template = Hanami::View::Template.new('index.html.erb')
# view = IndexView.new(template, {article: article})
#
# view.render # => Introducing Hanami::view
...
#
# @example with template and layout
# require 'hanami/view'
#
# class ApplicationLayout
# include Hanami::View::Layout
# end
#
# class IndexView
# include Hanami::View
# layout :application
# end
#
# template = Hanami::View::Template.new('index.html.erb')
# view = IndexView.new(template, {article: article})
#
# view.render # => ... Introducing Hanami::view
...
#
# @example with custom rendering
# require 'hanami/view'
#
# class IndexView
# include Hanami::View
#
# def render
# ArticleSerializer.new(article).render
# end
# end
#
# view = IndexView.new(nil, {article: article})
#
# view.render # => {title: ...}
def render
layout.render
end
# It tries to invoke a method for the view or a local for the given key.
# If the lookup fails, it returns a null object.
#
# @return [Object,Hanami::View::Rendering::NullLocal] the returning value
#
# @since 0.7.0
#
# @example
# <% if local(:plan).overdue? %>
# Your plan is overdue.
# <% end %>
def local(key)
if respond_to?(key)
__send__(key)
else
locals.fetch(key) { NullLocal.new(key) }
end
end
protected
# The output of the template rendering process.
#
# @return [String] the rendering output
#
# @raise [Hanami::View::MissingTemplateError] if the template is nil
#
# @api private
# @since 0.1.0
def rendered
template.render @scope
end
# The layout.
#
# @return [Class, Hanami::View::Rendering::NullLayout]
#
# @see Hanami::View::Layout
# @see Hanami::View.layout
# @see Hanami::View::Dsl#layout
#
# @api private
# @since 0.1.0
def layout
@layout ||= self.class.layout.new(@scope, rendered)
end
# The template.
#
# @return [Hanami::View::Template] the template
#
# @raise [Hanami::View::MissingTemplateError] if the template is nil
#
# @api private
# @since 0.1.0
def template
@template or raise MissingTemplateError.new(self.class.template, @scope.format)
end
# A set of objects available during the rendering process.
#
# @return [Hash]
#
# @see Hanami::View#initialize
#
# @api private
# @since 0.1.0
def locals
@locals
end
# Delegates missing methods to the scope.
#
# @see Hanami::View::Rendering::Scope
#
# @api private
# @since 0.1.0
#
# @example
# require 'hanami/view'
#
# class IndexView
# include Hanami::View
# end
#
# template = Hanami::View::Template.new('index.html.erb')
# view = IndexView.new(template, {article: article})
#
# view.article # => #
def method_missing(m)
@scope.__send__ m
end
end
# Render the given context and locals with the appropriate template.
# If there are registered subclasses, it choose the right class, according
# to the requested format.
#
# @param context [Hash] the context for the rendering process
# @option context [Symbol] :format the requested format
#
# @return [String] the output of the rendering process
#
# @raise [Hanami::View::MissingTemplateError] if it can't find a template
# for the given context
#
# @raise [Hanami::View::MissingFormatError] if the given context doesn't
# have the :format key
#
# @since 0.1.0
#
# @see Hanami::View#initialize
# @see Hanami::View#render
#
# @example
# require 'hanami/view'
#
# article = OpenStruct.new(title: 'Hello')
#
# module Articles
# class Show
# include Hanami::View
#
# def title
# @title ||= article.title.upcase
# end
# end
#
# class JsonShow < Show
# format :json
#
# def title
# super.downcase
# end
# end
# end
#
# Hanami::View.root = '/path/to/templates'
# Hanami::View.load!
#
# Articles::Show.render(format: :html, article: article)
# # => renders `articles/show.html.erb`
#
# Articles::Show.render(format: :json, article: article)
# # => renders `articles/show.json.erb`
#
# Articles::Show.render(format: :xml, article: article)
# # => raises Hanami::View::MissingTemplateError
def render(context)
registry.resolve(context).render
end
protected
# Loading mechanism hook.
#
# @api private
# @since 0.1.0
#
# @see Hanami::View.load!
def load!
super
load_registry!
end
private
# The registry that holds all the registered subclasses.
#
# @api private
# @since 0.1.0
#
# @see Hanami::View::Rendering::Registry
def registry
@registry ||= Registry.new(self)
end
# @api private
def load_registry!
@registry = nil
registry.freeze
end
end
end
end