module ActionView #:nodoc:
class ActionViewError < StandardError #:nodoc:
end
class MissingTemplate < ActionViewError #:nodoc:
end
# Action View templates can be written in three ways. If the template file has a .erb (or .rhtml) extension then it uses a mixture of ERb
# (included in Ruby) and HTML. If the template file has a .builder (or .rxml) extension then Jim Weirich's Builder::XmlMarkup library is used.
# If the template file has a .rjs extension then it will use ActionView::Helpers::PrototypeHelper::JavaScriptGenerator.
#
# = ERb
#
# You trigger ERb by using embeddings such as <% %>, <% -%>, and <%= %>. The <%= %> tag set is used when you want output. Consider the
# following loop for names:
#
# Names of all the people
# <% for person in @people %>
# Name: <%= person.name %>
# <% end %>
#
# The loop is setup in regular embedding tags <% %> and the name is written using the output embedding tag <%= %>. Note that this
# is not just a usage suggestion. Regular output functions like print or puts won't work with ERb templates. So this would be wrong:
#
# Hi, Mr. <% puts "Frodo" %>
#
# If you absolutely must write from within a function, you can use the TextHelper#concat.
#
# <%- and -%> suppress leading and trailing whitespace, including the trailing newline, and can be used interchangeably with <% and %>.
#
# == Using sub templates
#
# Using sub templates allows you to sidestep tedious replication and extract common display structures in shared templates. The
# classic example is the use of a header and footer (even though the Action Pack-way would be to use Layouts):
#
# <%= render "shared/header" %>
# Something really specific and terrific
# <%= render "shared/footer" %>
#
# As you see, we use the output embeddings for the render methods. The render call itself will just return a string holding the
# result of the rendering. The output embedding writes it to the current template.
#
# But you don't have to restrict yourself to static includes. Templates can share variables amongst themselves by using instance
# variables defined using the regular embedding tags. Like this:
#
# <% @page_title = "A Wonderful Hello" %>
# <%= render "shared/header" %>
#
# Now the header can pick up on the @page_title variable and use it for outputting a title tag:
#
#
<%= @page_title %>
#
# == Passing local variables to sub templates
#
# You can pass local variables to sub templates by using a hash with the variable names as keys and the objects as values:
#
# <%= render "shared/header", { :headline => "Welcome", :person => person } %>
#
# These can now be accessed in shared/header with:
#
# Headline: <%= headline %>
# First name: <%= person.first_name %>
#
# If you need to find out whether a certain local variable has been assigned a value in a particular render call,
# you need to use the following pattern:
#
# <% if local_assigns.has_key? :headline %>
# Headline: <%= headline %>
# <% end %>
#
# Testing using defined? headline will not work. This is an implementation restriction.
#
# == Template caching
#
# By default, Rails will compile each template to a method in order to render it. When you alter a template, Rails will
# check the file's modification time and recompile it.
#
# == Builder
#
# Builder templates are a more programmatic alternative to ERb. They are especially useful for generating XML content. An XmlMarkup object
# named +xml+ is automatically made available to templates with a .builder extension.
#
# Here are some basic examples:
#
# xml.em("emphasized") # => emphasized
# xml.em { xml.b("emph & bold") } # => emph & bold
# xml.a("A Link", "href"=>"http://onestepback.org") # => A Link
# xml.target("name"=>"compile", "option"=>"fast") # =>
# # NOTE: order of attributes is not specified.
#
# Any method with a block will be treated as an XML markup tag with nested markup in the block. For example, the following:
#
# xml.div {
# xml.h1(@person.name)
# xml.p(@person.bio)
# }
#
# would produce something like:
#
#
#
David Heinemeier Hansson
#
A product of Danish Design during the Winter of '79...
#
#
# A full-length RSS example actually used on Basecamp:
#
# xml.rss("version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/") do
# xml.channel do
# xml.title(@feed_title)
# xml.link(@url)
# xml.description "Basecamp: Recent items"
# xml.language "en-us"
# xml.ttl "40"
#
# for item in @recent_items
# xml.item do
# xml.title(item_title(item))
# xml.description(item_description(item)) if item_description(item)
# xml.pubDate(item_pubDate(item))
# xml.guid(@person.firm.account.url + @recent_items.url(item))
# xml.link(@person.firm.account.url + @recent_items.url(item))
#
# xml.tag!("dc:creator", item.author_name) if item_has_creator?(item)
# end
# end
# end
# end
#
# More builder documentation can be found at http://builder.rubyforge.org.
#
# == JavaScriptGenerator
#
# JavaScriptGenerator templates end in .rjs. Unlike conventional templates which are used to
# render the results of an action, these templates generate instructions on how to modify an already rendered page. This makes it easy to
# modify multiple elements on your page in one declarative Ajax response. Actions with these templates are called in the background with Ajax
# and make updates to the page where the request originated from.
#
# An instance of the JavaScriptGenerator object named +page+ is automatically made available to your template, which is implicitly wrapped in an ActionView::Helpers::PrototypeHelper#update_page block.
#
# When an .rjs action is called with +link_to_remote+, the generated JavaScript is automatically evaluated. Example:
#
# link_to_remote :url => {:action => 'delete'}
#
# The subsequently rendered delete.rjs might look like:
#
# page.replace_html 'sidebar', :partial => 'sidebar'
# page.remove "person-#{@person.id}"
# page.visual_effect :highlight, 'user-list'
#
# This refreshes the sidebar, removes a person element and highlights the user list.
#
# See the ActionView::Helpers::PrototypeHelper::GeneratorMethods documentation for more details.
class Base
include ERB::Util
attr_reader :finder
attr_accessor :base_path, :assigns, :template_extension, :first_render
attr_accessor :controller
attr_writer :template_format
attr_accessor :current_render_extension
attr_accessor :output_buffer
# Specify trim mode for the ERB compiler. Defaults to '-'.
# See ERb documentation for suitable values.
@@erb_trim_mode = '-'
cattr_accessor :erb_trim_mode
# Specify whether file modification times should be checked to see if a template needs recompilation
@@cache_template_loading = false
cattr_accessor :cache_template_loading
def self.cache_template_extensions=(*args)
ActiveSupport::Deprecation.warn("config.action_view.cache_template_extensions option has been deprecated and has no affect. " <<
"Please remove it from your config files.", caller)
end
# Specify whether RJS responses should be wrapped in a try/catch block
# that alert()s the caught exception (and then re-raises it).
@@debug_rjs = false
cattr_accessor :debug_rjs
attr_internal :request
delegate :request_forgery_protection_token, :template, :params, :session, :cookies, :response, :headers,
:flash, :logger, :action_name, :controller_name, :to => :controller
module CompiledTemplates #:nodoc:
# holds compiled template code
end
include CompiledTemplates
# Maps inline templates to their method names
cattr_accessor :method_names
@@method_names = {}
# Map method names to the names passed in local assigns so far
@@template_args = {}
# Cache public asset paths
cattr_reader :computed_public_paths
@@computed_public_paths = {}
class ObjectWrapper < Struct.new(:value) #:nodoc:
end
def self.helper_modules #:nodoc:
helpers = []
Dir.entries(File.expand_path("#{File.dirname(__FILE__)}/helpers")).sort.each do |file|
next unless file =~ /^([a-z][a-z_]*_helper).rb$/
require "action_view/helpers/#{$1}"
helper_module_name = $1.camelize
if Helpers.const_defined?(helper_module_name)
helpers << Helpers.const_get(helper_module_name)
end
end
return helpers
end
def initialize(view_paths = [], assigns_for_first_render = {}, controller = nil)#:nodoc:
@assigns = assigns_for_first_render
@assigns_added = nil
@controller = controller
@finder = TemplateFinder.new(self, view_paths)
end
# Renders the template present at template_path. If use_full_path is set to true,
# it's relative to the view_paths array, otherwise it's absolute. The hash in local_assigns
# is made available as local variables.
def render_file(template_path, use_full_path = true, local_assigns = {}) #:nodoc:
if defined?(ActionMailer) && defined?(ActionMailer::Base) && controller.is_a?(ActionMailer::Base) && !template_path.include?("/")
raise ActionViewError, <<-END_ERROR
Due to changes in ActionMailer, you need to provide the mailer_name along with the template name.
render "user_mailer/signup"
render :file => "user_mailer/signup"
If you are rendering a subtemplate, you must now use controller-like partial syntax:
render :partial => 'signup' # no mailer_name necessary
END_ERROR
end
Template.new(self, template_path, use_full_path, local_assigns).render_template
end
# Renders the template present at template_path (relative to the view_paths array).
# The hash in local_assigns is made available as local variables.
def render(options = {}, local_assigns = {}, &block) #:nodoc:
if options.is_a?(String)
render_file(options, true, local_assigns)
elsif options == :update
update_page(&block)
elsif options.is_a?(Hash)
use_full_path = options[:use_full_path]
options = options.reverse_merge(:locals => {}, :use_full_path => true)
if partial_layout = options.delete(:layout)
if block_given?
wrap_content_for_layout capture(&block) do
concat(render(options.merge(:partial => partial_layout)))
end
else
wrap_content_for_layout render(options) do
render(options.merge(:partial => partial_layout))
end
end
elsif options[:file]
render_file(options[:file], use_full_path || false, options[:locals])
elsif options[:partial] && options[:collection]
render_partial_collection(options[:partial], options[:collection], options[:spacer_template], options[:locals])
elsif options[:partial]
render_partial(options[:partial], ActionView::Base::ObjectWrapper.new(options[:object]), options[:locals])
elsif options[:inline]
template = InlineTemplate.new(self, options[:inline], options[:locals], options[:type])
render_template(template)
end
end
end
def render_template(template) #:nodoc:
template.render_template
end
# Returns true is the file may be rendered implicitly.
def file_public?(template_path)#:nodoc:
template_path.split('/').last[0,1] != '_'
end
# Returns a symbolized version of the :format parameter of the request,
# or :html by default.
#
# EXCEPTION: If the :format parameter is not set, the Accept header will be examined for
# whether it contains the JavaScript mime type as its first priority. If that's the case,
# it will be used. This ensures that Ajax applications can use the same URL to support both
# JavaScript and non-JavaScript users.
def template_format
return @template_format if @template_format
if controller && controller.respond_to?(:request)
parameter_format = controller.request.parameters[:format]
accept_format = controller.request.accepts.first
case
when parameter_format.blank? && accept_format != :js
@template_format = :html
when parameter_format.blank? && accept_format == :js
@template_format = :js
else
@template_format = parameter_format.to_sym
end
else
@template_format = :html
end
end
private
def wrap_content_for_layout(content)
original_content_for_layout, @content_for_layout = @content_for_layout, content
yield
ensure
@content_for_layout = original_content_for_layout
end
# Evaluate the local assigns and pushes them to the view.
def evaluate_assigns
unless @assigns_added
assign_variables_from_controller
@assigns_added = true
end
end
# Assigns instance variables from the controller to the view.
def assign_variables_from_controller
@assigns.each { |key, value| instance_variable_set("@#{key}", value) }
end
def execute(template)
send(template.method, template.locals) do |*names|
instance_variable_get "@content_for_#{names.first || 'layout'}"
end
end
end
end