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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:
#
# <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)
#
# == 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 %>
#
# == 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") # => <em>emphasized</em>
# xml.em { xml.b("emp & bold") } # => <em><b>emph &amp; bold</b></em>
# xml.a("A Link", "href"=>"http://onestepback.org") # => <a href="http://onestepback.org">A Link</a>
# xm.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.
class Base
include ERB::Util
attr_reader :first_render
attr_accessor :base_path, :assigns, :template_extension
attr_accessor :controller
attr_reader :logger, :params, :request, :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
# 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 local_assigns should be able to use string keys.
# Defaults to +true+. String keys are deprecated and will be removed
# shortly.
@@local_assigns_support_string_keys = true
cattr_accessor :local_assigns_support_string_keys
@@template_handlers = {}
module CompiledTemplates #:nodoc:
# holds compiled template code
end
include CompiledTemplates
# maps inline templates to their method names
@@method_names = {}
# map method names to their compile time
@@compile_time = {}
# map method names to the names passed in local assigns so far
@@template_args = {}
# count the number of inline templates
@@inline_template_count = 0
class ObjectWrapper < Struct.new(:value) #:nodoc:
end
def self.load_helpers(helper_dir)#:nodoc:
Dir.foreach(helper_dir) do |helper_file|
next unless helper_file =~ /^([a-z][a-z_]*_helper).rb$/
require File.join(helper_dir, $1)
helper_module_name = $1.camelize
class_eval("include ActionView::Helpers::#{helper_module_name}") if Helpers.const_defined?(helper_module_name)
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] = 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 <tt>template_path</tt>. If <tt>use_full_path</tt> is set to true,
# it's relative to the template_root, 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 = {})
@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 <tt>template_path</tt> (relative to the template_root).
# The hash in <tt>local_assigns</tt> 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], ActionView::Base::ObjectWrapper.new(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 <tt>template_extension</tt>.
# The hash in <tt>local_assigns</tt> 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 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(extension, template = nil, file_path = nil, local_assigns = {})
# compile the given template, if necessary
if compile_template?(template, file_path, local_assigns)
template ||= read_template_file(file_path, extension)
compile_template(extension, template, file_path, local_assigns)
end
# Get the method name for this template and run it
method_name = @@method_names[file_path || template]
evaluate_assigns
local_assigns = local_assigns.symbolize_keys if @@local_assigns_support_string_keys
send(method_name, local_assigns) 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 template_exists?(template_path, :rhtml)
'rhtml'
elsif template_exists?(template_path, :rxml)
'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_path = full_template_path(template_path, extension)
@@method_names.has_key?(file_path) || FileTest.exists?(file_path)
end
# This method reads a template file.
def read_template_file(template_path, extension)
File.read(template_path)
end
def evaluate_assigns
unless @assigns_added
assign_variables_from_controller
@assigns_added = true
end
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
# Return true if the given template was compiled for a superset of the keys in local_assigns
def supports_local_assigns?(render_symbol, local_assigns)
local_assigns.empty? ||
((args = @@template_args[render_symbol]) && local_assigns.all? { |k,_| args.has_key?(k) })
end
# Check whether compilation is necessary.
# Compile if the inline template or file has not been compiled yet.
# Or if local_assigns has a new key, which isn't supported by the compiled code yet.
# Or if the file has changed on disk and checking file mods hasn't been disabled.
def compile_template?(template, file_name, local_assigns)
method_key = file_name || template
render_symbol = @@method_names[method_key]
if @@compile_time[render_symbol] && supports_local_assigns?(render_symbol, local_assigns)
if file_name && !@@cache_template_loading
@@compile_time[render_symbol] < File.mtime(file_name)
end
else
true
end
end
# Create source code for given template
def create_template_source(extension, template, render_symbol, locals)
if extension && (extension.to_sym == :rxml)
body = "xml = Builder::XmlMarkup.new(:indent => 2)\n" +
"@controller.headers['Content-Type'] ||= 'text/xml'\n" +
template
else
body = ERB.new(template, nil, @@erb_trim_mode).src
end
@@template_args[render_symbol] ||= {}
locals_keys = @@template_args[render_symbol].keys | locals
@@template_args[render_symbol] = locals_keys.inject({}) { |h, k| h[k] = true; h }
locals_code = ""
locals_keys.each do |key|
locals_code << "#{key} = local_assigns[:#{key}] if local_assigns.has_key?(:#{key})\n"
end
"def #{render_symbol}(local_assigns)\n#{locals_code}#{body}\nend"
end
def assign_method_name(extension, template, file_name)
method_name = '_run_'
if extension && (extension.to_sym == :rxml)
method_name << 'xml_'
else
method_name << 'html_'
end
if file_name
file_path = File.expand_path(file_name)
base_path = File.expand_path(@base_path)
i = file_path.index(base_path)
l = base_path.length
method_name_file_part = i ? file_path[i+l+1,file_path.length-l-1] : file_path.clone
method_name_file_part.sub!(/\.r(ht|x)ml$/,'')
method_name_file_part.tr!('/:-', '_')
method_name_file_part.gsub!(/[^a-zA-Z0-9_]/){|s| s[0].to_s}
method_name += method_name_file_part
else
@@inline_template_count += 1
method_name << @@inline_template_count.to_s
end
@@method_names[file_name || template] = method_name.intern
end
def compile_template(extension, template, file_name, local_assigns)
method_key = file_name || template
render_symbol = @@method_names[method_key] || assign_method_name(extension, template, file_name)
render_source = create_template_source(extension, template, render_symbol, local_assigns.keys)
line_offset = @@template_args[render_symbol].size
line_offset += 2 if extension && (extension.to_sym == :rxml)
begin
unless file_name.blank?
CompiledTemplates.module_eval(render_source, file_name, -line_offset)
else
CompiledTemplates.module_eval(render_source, 'compiled-template', -line_offset)
end
rescue Object => e
if logger
logger.debug "ERROR: compiling #{render_symbol} RAISED #{e}"
logger.debug "Function body: #{render_source}"
logger.debug "Backtrace: #{e.backtrace.join("\n")}"
end
raise TemplateError.new(@base_path, method_key, @assigns, template, e)
end
@@compile_time[render_symbol] = Time.now
# logger.debug "Compiled template #{method_key}\n ==> #{render_symbol}" if logger
end
end
end
require 'action_view/template_error'
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