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module ActionView #:nodoc:
class ActionViewError < StandardError #: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:
#
# <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 @page_title 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 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 <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 +.builder+ 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 +.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_reader :logger, :response, :headers
attr_internal :cookies, :flash, :headers, :params, :request, :response, :session
attr_writer :template_format
attr_accessor :current_render_extension
# 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
# Specify whether file extension lookup should be cached, and whether template base path lookup should be cached.
# Should be +false+ for development environments. Defaults to +true+.
@@cache_template_extensions = true
cattr_accessor :cache_template_extensions
# 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
@@erb_variable = '_erbout'
cattr_accessor :erb_variable
delegate :request_forgery_protection_token, :to => :controller
@@template_handlers = HashWithIndifferentAccess.new
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 = {}
@@template_handlers = {}
@@default_template_handlers = nil
class ObjectWrapper < Struct.new(:value) #:nodoc:
end
def self.load_helpers #:nodoc:
Dir.entries("#{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)
include Helpers.const_get(helper_module_name)
end
end
end
# Register a class that knows how to handle template files with the given
# extension. This can be used to implement new template types.
# The constructor for the class must take the ActiveView::Base instance
# as a parameter, and the class must implement a #render method that
# takes the contents of the template to render as well as the Hash of
# local assigns available to the template. The #render method ought to
# return the rendered template as a string.
def self.register_template_handler(extension, klass)
@@template_handlers[extension.to_sym] = klass
TemplateFinder.update_extension_cache_for(extension.to_s)
end
def self.template_handler_extensions
@@template_handlers.keys.map(&:to_s).sort
end
def self.register_default_template_handler(extension, klass)
register_template_handler(extension, klass)
@@default_template_handlers = klass
end
def self.handler_class_for_extension(extension)
(extension && @@template_handlers[extension.to_sym]) || @@default_template_handlers
end
register_default_template_handler :erb, TemplateHandlers::ERB
register_template_handler :rjs, TemplateHandlers::RJS
register_template_handler :builder, TemplateHandlers::Builder
# TODO: Depreciate old template extensions
register_template_handler :rhtml, TemplateHandlers::ERB
register_template_handler :rxml, TemplateHandlers::Builder
def initialize(view_paths = [], assigns_for_first_render = {}, controller = nil)#:nodoc:
@assigns = assigns_for_first_render
@assigns_added = nil
@controller = controller
@logger = controller && controller.logger
@finder = TemplateFinder.new(self, view_paths)
end
# Renders the template present at <tt>template_path</tt>. If <tt>use_full_path</tt> is set to true,
# it's relative to the view_paths array, otherwise it's absolute. The hash in <tt>local_assigns</tt>
# 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 = Template.new(self, template_path, use_full_path, local_assigns)
begin
render_template(template)
rescue Exception => e
if TemplateError === e
e.sub_template_of(template.filename)
raise e
else
raise TemplateError.new(template, @assigns, e)
end
end
end
# Renders the template present at <tt>template_path</tt> (relative to the view_paths array).
# The hash in <tt>local_assigns</tt> is made available as local variables.
def render(options = {}, old_local_assigns = {}, &block) #:nodoc:
if options.is_a?(String)
render_file(options, true, old_local_assigns)
elsif options == :update
update_page(&block)
elsif options.is_a?(Hash)
options = options.reverse_merge(:locals => {}, :use_full_path => true)
if options[:layout]
path, partial_name = partial_pieces(options.delete(:layout))
if block_given?
wrap_content_for_layout capture(&block) do
concat(render(options.merge(:partial => "#{path}/#{partial_name}")), block.binding)
end
else
wrap_content_for_layout render(options) do
render(options.merge(:partial => "#{path}/#{partial_name}"))
end
end
elsif options[:file]
render_file(options[:file], options[:use_full_path], 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 = Template.new(self, options[:inline], false, options[:locals], true, options[:type])
render_template(template)
end
end
end
# Renders the +template+ which is given as a string as either erb or builder depending on <tt>template_extension</tt>.
# The hash in <tt>local_assigns</tt> is made available as local variables.
def render_template(template) #:nodoc:
handler = template.handler
@current_render_extension = template.extension
if handler.compilable?
compile_and_render_template(handler, template)
else
handler.render(template.source, template.locals)
end
end
# Returns true is the file may be rendered implicitly.
def file_public?(template_path)#:nodoc:
template_path.split('/').last[0,1] != '_'
end
# 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
returning(yield) { @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
# Render the provided template with the given local assigns. If the template has not been rendered with the provided
# local assigns yet, or if the template has been updated on disk, then the template will be compiled to a method.
#
# Either, but not both, of template and file_path may be nil. If file_path is given, the template
# will only be read if it has to be compiled.
#
def compile_and_render_template(handler, template) #:nodoc:
# compile the given template, if necessary
handler.compile_template(template)
# Get the method name for this template and run it
method_name = @@method_names[template.method_key]
evaluate_assigns
send(method_name, template.locals) do |*name|
instance_variable_get "@content_for_#{name.first || 'layout'}"
end
end
end
end
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