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rails--rails/actionpack/lib/action_view/base.rb
2009-05-13 12:00:15 -07:00

296 lines
11 KiB
Ruby

require 'active_support/core_ext/module/attr_internal'
require 'active_support/core_ext/module/delegation'
module ActionView #:nodoc:
class ActionViewError < StandardError #:nodoc:
end
class MissingTemplate < ActionViewError #:nodoc:
attr_reader :path, :action_name
def initialize(paths, path, template_format = nil)
@path = path
@action_name = path.split("/").last.split(".")[0...-1].join(".")
full_template_path = path.include?('.') ? path : "#{path}.erb"
display_paths = paths.compact.join(":")
template_type = (path =~ /layouts/i) ? 'layout' : 'template'
super("Missing #{template_type} #{full_template_path} in view path #{display_paths}")
end
end
# Action View templates can be written in three ways. If the template file has a <tt>.erb</tt> (or <tt>.rhtml</tt>) extension then it uses a mixture of ERb
# (included in Ruby) and HTML. If the template file has a <tt>.builder</tt> (or <tt>.rxml</tt>) extension then Jim Weirich's Builder::XmlMarkup library is used.
# If the template file has a <tt>.rjs</tt> 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:
#
# <b>Names of all the people</b>
# <% for person in @people %>
# Name: <%= person.name %><br/>
# <% 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 <tt>@page_title</tt> variable and use it for outputting a title tag:
#
# <title><%= @page_title %></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 <tt>shared/header</tt> 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 <tt>defined? headline</tt> 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 <tt>.builder</tt> extension.
#
# Here are some basic examples:
#
# xml.em("emphasized") # => <em>emphasized</em>
# xml.em { xml.b("emph & bold") } # => <em><b>emph &amp; bold</b></em>
# xml.a("A Link", "href"=>"http://onestepback.org") # => <a href="http://onestepback.org">A Link</a>
# xml.target("name"=>"compile", "option"=>"fast") # => <target option="fast" name="compile"\>
# # 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:
#
# <div>
# <h1>David Heinemeier Hansson</h1>
# <p>A product of Danish Design during the Winter of '79...</p>
# </div>
#
# 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 <tt>.rjs</tt>. 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 <tt>.rjs</tt> action is called with +link_to_remote+, the generated JavaScript is automatically evaluated. Example:
#
# link_to_remote :url => {:action => 'delete'}
#
# The subsequently rendered <tt>delete.rjs</tt> 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 Helpers, Rendering, Partials, ::ERB::Util
extend ActiveSupport::Memoizable
attr_accessor :base_path, :assigns, :template_extension, :formats
attr_accessor :controller
attr_accessor :output_buffer
class << self
delegate :erb_trim_mode=, :to => 'ActionView::TemplateHandlers::ERB'
delegate :logger, :to => 'ActionController::Base'
end
@@debug_rjs = false
##
# :singleton-method:
# Specify whether RJS responses should be wrapped in a try/catch block
# that alert()s the caught exception (and then re-raises it).
cattr_accessor :debug_rjs
# Specify whether templates should be cached. Otherwise the file we be read everytime it is accessed.
# Automatically reloading templates are not thread safe and should only be used in development mode.
@@cache_template_loading = nil
cattr_accessor :cache_template_loading
def self.cache_template_loading?
ActionController::Base.allow_concurrency || (cache_template_loading.nil? ? !ActiveSupport::Dependencies.load? : cache_template_loading)
end
attr_internal :request, :layout
delegate :controller_path, :to => :controller, :allow_nil => true
delegate :request_forgery_protection_token, :template, :params, :session, :cookies, :response, :headers,
:flash, :action_name, :controller_name, :to => :controller
delegate :logger, :to => :controller, :allow_nil => true
delegate :find_by_parts, :to => :view_paths
module CompiledTemplates #:nodoc:
# holds compiled template code
end
include CompiledTemplates
def self.process_view_paths(value)
ActionView::PathSet.new(Array(value))
end
attr_reader :helpers
class ProxyModule < Module
def initialize(receiver)
@receiver = receiver
end
def include(*args)
super(*args)
@receiver.extend(*args)
end
end
def initialize(view_paths = [], assigns_for_first_render = {}, controller = nil, formats = nil)#:nodoc:
@formats = formats || [:html]
@assigns = assigns_for_first_render
@assigns_added = nil
@controller = controller
@helpers = ProxyModule.new(self)
self.view_paths = view_paths
@_first_render = nil
@_current_render = nil
end
attr_reader :view_paths
def view_paths=(paths)
@view_paths = self.class.process_view_paths(paths)
end
# Access the current template being rendered.
# Returns a ActionView::Template object.
def template
@_current_render
end
def template=(template) #:nodoc:
@_first_render ||= template
@_current_render = template
end
def with_template(current_template)
last_template, self.template = template, current_template
yield
ensure
self.template = last_template
end
def punctuate_body!(part)
flush_output_buffer
response.body_parts << part
nil
end
private
# Evaluates the local assigns and controller ivars, pushes them to the view.
def _evaluate_assigns_and_ivars #:nodoc:
unless @assigns_added
@assigns.each { |key, value| instance_variable_set("@#{key}", value) }
_copy_ivars_from_controller
@assigns_added = true
end
end
def _copy_ivars_from_controller #:nodoc:
if @controller
variables = @controller.instance_variable_names
variables -= @controller.protected_instance_variables if @controller.respond_to?(:protected_instance_variables)
variables.each { |name| instance_variable_set(name, @controller.instance_variable_get(name)) }
end
end
def _set_controller_content_type(content_type) #:nodoc:
if controller.respond_to?(:response)
controller.response.content_type ||= content_type
end
end
end
end