require 'erb' module ActionView #:nodoc: class ActionViewError < StandardError #:nodoc: end # Action View templates can be written in two ways. If the template file has a +.rhtml+ extension then it uses a mixture of ERb # (included in Ruby) and HTML. If the template file has a +.rxml+ extension then Jim Weirich's Builder::XmlMarkup library is used. # # = ERb # # You trigger ERb by using embeddings such as <% %> and <%= %>. The difference is whether you want output or not. 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) # # == 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 in 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 %> # # == 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 +.rxml+ extension. # # Here are some basic examples: # # xml.em("emphasized") # => emphasized # xml.em { xml.b("emp & bold") } # => emph & bold # xml.a("A Link", "href"=>"http://onestepback.org") # => A Link # xm.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. class Base include ERB::Util attr_reader :first_render attr_accessor :base_path, :assigns, :template_extension attr_accessor :controller attr_reader :logger, :params, :response, :session, :headers, :flash # Specify trim mode for the ERB compiler. Defaults to '-'. # See ERB documentation for suitable values. @@erb_trim_mode = '-' cattr_accessor :erb_trim_mode @@cache_template_loading = false # Unused at the moment cattr_accessor :cache_template_loading @@template_handlers = {} @@compiled_templates = CompiledTemplates.new include @@compiled_templates def self.load_helpers(helper_dir)#:nodoc: Dir.foreach(helper_dir) do |helper_file| next unless helper_file =~ /_helper.rb$/ require helper_dir + helper_file helper_module_name = helper_file.capitalize.gsub(/_([a-z])/) { |m| $1.capitalize }[0..-4] class_eval("include ActionView::Helpers::#{helper_module_name}") if Helpers.const_defined?(helper_module_name) end end def self.register_template_handler(extension, klass) @@template_handlers[extension] = klass end def initialize(base_path = nil, assigns_for_first_render = {}, controller = nil)#:nodoc: @base_path, @assigns = base_path, assigns_for_first_render @assigns_added = nil @controller = controller @logger = controller && controller.logger end # Renders the template present at template_path. If use_full_path is set to true, # it's relative to the template_root, 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 = {}) @first_render = template_path if @first_render.nil? if use_full_path template_extension = pick_template_extension(template_path) template_file_name = full_template_path(template_path, template_extension) else template_file_name = template_path template_extension = template_path.split('.').last end template_source = nil # Don't read the source until we know that it is required begin render_template(template_extension, template_source, template_file_name, local_assigns) rescue Exception => e if TemplateError === e e.sub_template_of(template_file_name) raise e else raise TemplateError.new(@base_path, template_file_name, @assigns, template_source, e) end end end # Renders the template present at template_path (relative to the template_root). # The hash in local_assigns is made available as local variables. def render(options = {}, old_local_assigns = {}) if options.is_a?(String) render_file(options, true, old_local_assigns) elsif options.is_a?(Hash) options[:locals] ||= {} options[:use_full_path] = options[:use_full_path].nil? ? true : options[:use_full_path] if 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], options[:object], options[:locals]) elsif options[:inline] render_template(options[:type] || :rhtml, options[:inline], nil, options[:locals] || {}) end end end # Renders the +template+ which is given as a string as either rhtml or rxml depending on template_extension. # The hash in local_assigns is made available as local variables. def render_template(template_extension, template, file_path = nil, local_assigns = {}) if handler = @@template_handlers[template_extension] template ||= read_template_file(file_path, template_extension) # Make sure that a lazyily-read template is loaded. delegate_render(handler, template, local_assigns) else compile_and_render_template(template_extension, template, file_path, local_assigns) end end # Render the privded 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 but template is nil, the template # will only be read if it has to be compiled. # def compile_and_render_template(extension, template = nil, file_path = nil, local_assigns = {}) file_path = File.expand_path(file_path) if file_path identifier = file_path || template # either might be nil. Prefer to use the file_path as a key names, params = split_locals(local_assigns) compile = ! @@compiled_templates.compiled?(identifier, names) # Compile the template if it hasn't been done if ! compile && file_path # If the file path is given, recompile if the mtime is new. compiled_at = @@compiled_templates.mtime(identifier, names) compile = compiled_at.nil? || (mtime = File.mtime(file_path)).nil? || compiled_at < mtime end if compile template ||= read_template_file(file_path, extension) compile_template(extension, file_path || 'inline-template', identifier, template, names) end # Get the selector for this template and names, then call the method. selector = @@compiled_templates.selector(identifier, names) evaluate_assigns send(selector, *params) do |*name| instance_variable_get "@content_for_#{name.first || 'layout'}" end end def pick_template_extension(template_path)#:nodoc: if match = delegate_template_exists?(template_path) match.first elsif erb_template_exists?(template_path) 'rhtml' elsif builder_template_exists?(template_path) 'rxml' else raise ActionViewError, "No rhtml, rxml, or delegate template found for #{template_path}" end end def delegate_template_exists?(template_path)#:nodoc: @@template_handlers.find { |k,| template_exists?(template_path, k) } end def erb_template_exists?(template_path)#:nodoc: template_exists?(template_path, 'rhtml') end def builder_template_exists?(template_path)#:nodoc: template_exists?(template_path, 'rxml') end def file_exists?(template_path)#:nodoc: erb_template_exists?(template_path) || builder_template_exists?(template_path) || delegate_template_exists?(template_path) end # Returns true is the file may be rendered implicitly. def file_public?(template_path)#:nodoc: template_path.split('/').last[0,1] != '_' end private def full_template_path(template_path, extension) "#{@base_path}/#{template_path}.#{extension}" end def template_exists?(template_path, extension) File.file?(full_template_path(template_path, extension)) end # This method reads a template file. No, it doesn't check mtimes, look to check if the template # has been compiled, or check your date of birth. It reads the template file. Crazy, I know. def read_template_file(template_path, extension) File.read(template_path) end # Split the provided hash of local assigns into two arrays, one of the names, and another of the value # The arrays are guarenteed to be in matching order, and also ordered the same for different hashes. def split_locals(assigns) names, values = [], [] assigns.to_a.sort_by {|pair| pair.first.to_s}.each do |name, value| names << name values << value end return [names, values] end def evaluate_assigns unless @assigns_added assign_variables_from_controller @assigns_added = true end end # Compile the template to a method using a CompiledTemplates instance. def compile_template(extension, file_path, identifier, template, local_names = []) line_no = 0 case extension && extension.to_sym when :rxml # Initialize the xml variable to the builder instance. source_code = \ "xml = Builder::XmlMarkup.new(:indent => 2) @controller.headers['Content-Type'] ||= 'text/xml'\n" + template line_no = -2 # offset extra line. else # Assume rhtml source_code = ERB.new(template, nil, @@erb_trim_mode).src end @@compiled_templates.compile_source(identifier, local_names, source_code, line_no, file_path) end def delegate_render(handler, template, local_assigns) handler.new(self).render(template, local_assigns) end def assign_variables_from_controller @assigns.each { |key, value| instance_variable_set("@#{key}", value) } end end end require 'action_view/template_error'