module ActionView
# There's also a convenience method for rendering sub templates within the current controller that depends on a
# single object (we call this kind of sub templates for partials). It relies on the fact that partials should
# follow the naming convention of being prefixed with an underscore -- as to separate them from regular
# templates that could be rendered on their own.
#
# In a template for Advertiser#account:
#
# <%= render :partial => "account" %>
#
# This would render "advertiser/_account.erb" and pass the instance variable @account in as a local variable
# +account+ to the template for display.
#
# In another template for Advertiser#buy, we could have:
#
# <%= render :partial => "account", :locals => { :account => @buyer } %>
#
# <% for ad in @advertisements %>
# <%= render :partial => "ad", :locals => { :ad => ad } %>
# <% end %>
#
# This would first render "advertiser/_account.erb" with @buyer passed in as the local variable +account+, then
# render "advertiser/_ad.erb" and pass the local variable +ad+ to the template for display.
#
# == Rendering a collection of partials
#
# The example of partial use describes a familiar pattern where a template needs to iterate over an array and
# render a sub template for each of the elements. This pattern has been implemented as a single method that
# accepts an array and renders a partial by the same name as the elements contained within. So the three-lined
# example in "Using partials" can be rewritten with a single line:
#
# <%= render :partial => "ad", :collection => @advertisements %>
#
# This will render "advertiser/_ad.erb" and pass the local variable +ad+ to the template for display. An
# iteration counter will automatically be made available to the template with a name of the form
# +partial_name_counter+. In the case of the example above, the template would be fed +ad_counter+.
#
# NOTE: Due to backwards compatibility concerns, the collection can't be one of hashes. Normally you'd also
# just keep domain objects, like Active Records, in there.
#
# == Rendering shared partials
#
# Two controllers can share a set of partials and render them like this:
#
# <%= render :partial => "advertisement/ad", :locals => { :ad => @advertisement } %>
#
# This will render the partial "advertisement/_ad.erb" regardless of which controller this is being called from.
#
# == Rendering objects with the RecordIdentifier
#
# Instead of explicitly naming the location of a partial, you can also let the RecordIdentifier do the work if
# you're following its conventions for RecordIdentifier#partial_path. Examples:
#
# # @account is an Account instance, so it uses the RecordIdentifier to replace
# # <%= render :partial => "accounts/account", :locals => { :account => @buyer } %>
# <%= render :partial => @account %>
#
# # @posts is an array of Post instances, so it uses the RecordIdentifier to replace
# # <%= render :partial => "posts/post", :collection => @posts %>
# <%= render :partial => @posts %>
#
# == Rendering the default case
#
# If you're not going to be using any of the options like collections or layouts, you can also use the short-hand
# defaults of render to render partials. Examples:
#
# # Instead of <%= render :partial => "account" %>
# <%= render "account" %>
#
# # Instead of <%= render :partial => "account", :locals => { :account => @buyer } %>
# <%= render "account", :account => @buyer %>
#
# # @account is an Account instance, so it uses the RecordIdentifier to replace
# # <%= render :partial => "accounts/account", :locals => { :account => @account } %>
# <%= render(@account) %>
#
# # @posts is an array of Post instances, so it uses the RecordIdentifier to replace
# # <%= render :partial => "posts/post", :collection => @posts %>
# <%= render(@posts) %>
#
# == Rendering partials with layouts
#
# Partials can have their own layouts applied to them. These layouts are different than the ones that are
# specified globally for the entire action, but they work in a similar fashion. Imagine a list with two types
# of users:
#
# <%# app/views/users/index.html.erb &>
# Here's the administrator:
# <%= render :partial => "user", :layout => "administrator", :locals => { :user => administrator } %>
#
# Here's the editor:
# <%= render :partial => "user", :layout => "editor", :locals => { :user => editor } %>
#
# <%# app/views/users/_user.html.erb &>
# Name: <%= user.name %>
#
# <%# app/views/users/_administrator.html.erb &>
# <div id="administrator">
# Budget: $<%= user.budget %>
# <%= yield %>
# </div>
#
# <%# app/views/users/_editor.html.erb &>
# <div id="editor">
# Deadline: <%= user.deadline %>
# <%= yield %>
# </div>
#
# ...this will return:
#
# Here's the administrator:
# <div id="administrator">
# Budget: $<%= user.budget %>
# Name: <%= user.name %>
# </div>
#
# Here's the editor:
# <div id="editor">
# Deadline: <%= user.deadline %>
# Name: <%= user.name %>
# </div>
#
# You can also apply a layout to a block within any template:
#
# <%# app/views/users/_chief.html.erb &>
# <% render(:layout => "administrator", :locals => { :user => chief }) do %>
# Title: <%= chief.title %>
# <% end %>
#
# ...this will return:
#
# <div id="administrator">
# Budget: $<%= user.budget %>
# Title: <%= chief.name %>
# </div>
#
# As you can see, the <tt>:locals</tt> hash is shared between both the partial and its layout.
#
# If you pass arguments to "yield" then this will be passed to the block. One way to use this is to pass
# an array to layout and treat it as an enumerable.
#
# <%# app/views/users/_user.html.erb &>
# <div class="user">
# Budget: $<%= user.budget %>
# <%= yield user %>
# </div>
#
# <%# app/views/users/index.html.erb &>
# <% render :layout => @users do |user| %>
# Title: <%= user.title %>
# <% end %>
#
# This will render the layout for each user and yield to the block, passing the user, each time.
#
# You can also yield multiple times in one layout and use block arguments to differentiate the sections.
#
# <%# app/views/users/_user.html.erb &>
# <div class="user">
# <%= yield user, :header %>
# Budget: $<%= user.budget %>
# <%= yield user, :footer %>
# </div>
#
# <%# app/views/users/index.html.erb &>
# <% render :layout => @users do |user, section| %>
# <%- case section when :header -%>
# Title: <%= user.title %>
# <%- when :footer -%>
# Deadline: <%= user.deadline %>
# <%- end -%>
# <% end %>
module Partials
extend ActiveSupport::Memoizable
extend ActiveSupport::Concern
included do
attr_accessor :_partial
end
def _render_partial_from_controller(*args)
@assigns_added = false
_render_partial(*args)
end
def _render_partial(options = {}) #:nodoc:
options[:locals] ||= {}
case path = partial = options[:partial]
when *_array_like_objects
return _render_partial_collection(partial, options)
else
if partial.is_a?(ActionView::Helpers::FormBuilder)
path = partial.class.to_s.demodulize.underscore.sub(/_builder$/, '')
options[:locals].merge!(path.to_sym => partial)
elsif !partial.is_a?(String)
options[:object] = object = partial
path = ActionController::RecordIdentifier.partial_path(object, controller_path)
end
_, _, prefix, object = parts = partial_parts(path, options)
parts[1] = {:formats => parts[1]}
template = find_by_parts(*parts)
_render_partial_object(template, options, (object unless object == true))
end
end
private
def partial_parts(name, options)
segments = name.split("/")
parts = segments.pop.split(".")
case parts.size
when 1
parts
when 2, 3
extension = parts.delete_at(1).to_sym
if formats.include?(extension)
self.formats.replace [extension]
end
parts.pop if parts.size == 2
end
path = parts.join(".")
prefix = segments[0..-1].join("/")
prefix = prefix.blank? ? controller_path : prefix
parts = [path, formats, prefix]
parts.push options[:object] || true
end
def _render_partial_with_block(layout, block, options)
@_proc_for_layout = block
concat(_render_partial(options.merge(:partial => layout)))
ensure
@_proc_for_layout = nil
end
def _render_partial_with_layout(layout, options)
if layout
prefix = controller && !layout.include?("/") ? controller.controller_path : nil
layout = find_by_parts(layout, {:formats => formats}, prefix, true)
end
content = _render_partial(options)
return _render_content_with_layout(content, layout, options[:locals])
end
def _array_like_objects
array_like = [Array]
if defined?(ActiveRecord)
array_like.push(ActiveRecord::Associations::AssociationCollection, ActiveRecord::NamedScope::Scope)
end
array_like
end
def _render_partial_object(template, options, object = nil)
if options.key?(:collection)
_render_partial_collection(options.delete(:collection), options, template)
else
locals = (options[:locals] ||= {})
object ||= locals[:object] || locals[template.variable_name]
_set_locals(object, locals, template, options)
options[:_template] = template
_render_template(template, locals)
end
end
def _set_locals(object, locals, template, options)
locals[:object] = locals[template.variable_name] = object
locals[options[:as]] = object if options[:as]
end
def _render_partial_collection(collection, options = {}, passed_template = nil) #:nodoc:
return nil if collection.blank?
spacer = options[:spacer_template] ? _render_partial(:partial => options[:spacer_template]) : ''
locals = (options[:locals] ||= {})
index, @_partial_path = 0, nil
collection.map do |object|
options[:_template] = template = passed_template || begin
_partial_path =
ActionController::RecordIdentifier.partial_path(object, controller_path)
template = _pick_partial_template(_partial_path)
end
_set_locals(object, locals, template, options)
locals[template.counter_name] = index
index += 1
_render_template(template, locals)
end.join(spacer)
end
def _pick_partial_template(partial_path) #:nodoc:
prefix = controller_path unless partial_path.include?('/')
find_by_parts(partial_path, {:formats => formats}, prefix, true)
end
memoize :_pick_partial_template
end
end
