require 'thread'
require 'cgi'
require 'action_view/helpers/url_helper'
require 'action_view/helpers/tag_helper'
require 'active_support/core_ext/file'
require 'active_support/core_ext/object/blank'
module ActionView
# = Action View Asset Tag Helpers
module Helpers #:nodoc:
# This module provides methods for generating HTML that links views to assets such
# as images, javascripts, stylesheets, and feeds. These methods do not verify
# the assets exist before linking to them:
#
# image_tag("rails.png")
# # =>
# stylesheet_link_tag("application")
# # =>
#
# === Using asset hosts
#
# By default, Rails links to these assets on the current host in the public
# folder, but you can direct Rails to link to assets from a dedicated asset
# server by setting ActionController::Base.asset_host in the application
# configuration, typically in config/environments/production.rb.
# For example, you'd define assets.example.com to be your asset
# host this way:
#
# ActionController::Base.asset_host = "assets.example.com"
#
# Helpers take that into account:
#
# image_tag("rails.png")
# # =>
# stylesheet_link_tag("application")
# # =>
#
# Browsers typically open at most two simultaneous connections to a single
# host, which means your assets often have to wait for other assets to finish
# downloading. You can alleviate this by using a %d wildcard in the
# +asset_host+. For example, "assets%d.example.com". If that wildcard is
# present Rails distributes asset requests among the corresponding four hosts
# "assets0.example.com", ..., "assets3.example.com". With this trick browsers
# will open eight simultaneous connections rather than two.
#
# image_tag("rails.png")
# # =>
# stylesheet_link_tag("application")
# # =>
#
# To do this, you can either setup four actual hosts, or you can use wildcard
# DNS to CNAME the wildcard to a single asset host. You can read more about
# setting up your DNS CNAME records from your ISP.
#
# Note: This is purely a browser performance optimization and is not meant
# for server load balancing. See http://www.die.net/musings/page_load_time/
# for background.
#
# Alternatively, you can exert more control over the asset host by setting
# +asset_host+ to a proc like this:
#
# ActionController::Base.asset_host = Proc.new { |source|
# "http://assets#{source.hash % 2 + 1}.example.com"
# }
# image_tag("rails.png")
# # =>
# stylesheet_link_tag("application")
# # =>
#
# The example above generates "http://assets1.example.com" and
# "http://assets2.example.com". This option is useful for example if
# you need fewer/more than four hosts, custom host names, etc.
#
# As you see the proc takes a +source+ parameter. That's a string with the
# absolute path of the asset with any extensions and timestamps in place,
# for example "/images/rails.png?1230601161".
#
# ActionController::Base.asset_host = Proc.new { |source|
# if source.starts_with?('/images')
# "http://images.example.com"
# else
# "http://assets.example.com"
# end
# }
# image_tag("rails.png")
# # =>
# stylesheet_link_tag("application")
# # =>
#
# Alternatively you may ask for a second parameter +request+. That one is
# particularly useful for serving assets from an SSL-protected page. The
# example proc below disables asset hosting for HTTPS connections, while
# still sending assets for plain HTTP requests from asset hosts. If you don't
# have SSL certificates for each of the asset hosts this technique allows you
# to avoid warnings in the client about mixed media.
#
# ActionController::Base.asset_host = Proc.new { |source, request|
# if request.ssl?
# "#{request.protocol}#{request.host_with_port}"
# else
# "#{request.protocol}assets.example.com"
# end
# }
#
# You can also implement a custom asset host object that responds to +call+
# and takes either one or two parameters just like the proc.
#
# config.action_controller.asset_host = AssetHostingWithMinimumSsl.new(
# "http://asset%d.example.com", "https://asset1.example.com"
# )
#
# === Customizing the asset path
#
# By default, Rails appends asset's timestamps to all asset paths. This allows
# you to set a cache-expiration date for the asset far into the future, but
# still be able to instantly invalidate it by simply updating the file (and
# hence updating the timestamp, which then updates the URL as the timestamp
# is part of that, which in turn busts the cache).
#
# It's the responsibility of the web server you use to set the far-future
# expiration date on cache assets that you need to take advantage of this
# feature. Here's an example for Apache:
#
# # Asset Expiration
# ExpiresActive On
#
# ExpiresDefault "access plus 1 year"
#
#
# Also note that in order for this to work, all your application servers must
# return the same timestamps. This means that they must have their clocks
# synchronized. If one of them drifts out of sync, you'll see different
# timestamps at random and the cache won't work. In that case the browser
# will request the same assets over and over again even thought they didn't
# change. You can use something like Live HTTP Headers for Firefox to verify
# that the cache is indeed working.
#
# This strategy works well enough for most server setups and requires the
# least configuration, but if you deploy several application servers at
# different times - say to handle a temporary spike in load - then the
# asset time stamps will be out of sync. In a setup like this you may want
# to set the way that asset paths are generated yourself.
#
# Altering the asset paths that Rails generates can be done in two ways.
# The easiest is to define the RAILS_ASSET_ID environment variable. The
# contents of this variable will always be used in preference to
# calculated timestamps. A more complex but flexible way is to set
# ActionController::Base.config.asset_path to a proc
# that takes the unmodified asset path and returns the path needed for
# your asset caching to work. Typically you'd do something like this in
# config/environments/production.rb:
#
# # Normally you'd calculate RELEASE_NUMBER at startup.
# RELEASE_NUMBER = 12345
# config.action_controller.asset_path_template = proc { |asset_path|
# "/release-#{RELEASE_NUMBER}#{asset_path}"
# }
#
# This example would cause the following behaviour on all servers no
# matter when they were deployed:
#
# image_tag("rails.png")
# # =>
# stylesheet_link_tag("application")
# # =>
#
# Changing the asset_path does require that your web servers have
# knowledge of the asset template paths that you rewrite to so it's not
# suitable for out-of-the-box use. To use the example given above you
# could use something like this in your Apache VirtualHost configuration:
#
#
# # Some browsers still send conditional-GET requests if there's a
# # Last-Modified header or an ETag header even if they haven't
# # reached the expiry date sent in the Expires header.
# Header unset Last-Modified
# Header unset ETag
# FileETag None
#
# # Assets requested using a cache-busting filename should be served
# # only once and then cached for a really long time. The HTTP/1.1
# # spec frowns on hugely-long expiration times though and suggests
# # that assets which never expire be served with an expiration date
# # 1 year from access.
# ExpiresActive On
# ExpiresDefault "access plus 1 year"
#
#
# # We use cached-busting location names with the far-future expires
# # headers to ensure that if a file does change it can force a new
# # request. The actual asset filenames are still the same though so we
# # need to rewrite the location from the cache-busting location to the
# # real asset location so that we can serve it.
# RewriteEngine On
# RewriteRule ^/release-\d+/(images|javascripts|stylesheets)/(.*)$ /$1/$2 [L]
module AssetTagHelper
# Returns a link tag that browsers and news readers can use to auto-detect
# an RSS or ATOM feed. The +type+ can either be :rss (default) or
# :atom. Control the link options in url_for format using the
# +url_options+. You can modify the LINK tag itself in +tag_options+.
#
# ==== Options
# * :rel - Specify the relation of this link, defaults to "alternate"
# * :type - Override the auto-generated mime type
# * :title - Specify the title of the link, defaults to the +type+
#
# ==== Examples
# auto_discovery_link_tag # =>
#
# auto_discovery_link_tag(:atom) # =>
#
# auto_discovery_link_tag(:rss, {:action => "feed"}) # =>
#
# auto_discovery_link_tag(:rss, {:action => "feed"}, {:title => "My RSS"}) # =>
#
# auto_discovery_link_tag(:rss, {:controller => "news", :action => "feed"}) # =>
#
# auto_discovery_link_tag(:rss, "http://www.example.com/feed.rss", {:title => "Example RSS"}) # =>
#
def auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})
tag(
"link",
"rel" => tag_options[:rel] || "alternate",
"type" => tag_options[:type] || Mime::Type.lookup_by_extension(type.to_s).to_s,
"title" => tag_options[:title] || type.to_s.upcase,
"href" => url_options.is_a?(Hash) ? url_for(url_options.merge(:only_path => false)) : url_options
)
end
# Computes the path to a javascript asset in the public javascripts directory.
# If the +source+ filename has no extension, .js will be appended (except for explicit URIs)
# Full paths from the document root will be passed through.
# Used internally by javascript_include_tag to build the script path.
#
# ==== Examples
# javascript_path "xmlhr" # => /javascripts/xmlhr.js
# javascript_path "dir/xmlhr.js" # => /javascripts/dir/xmlhr.js
# javascript_path "/dir/xmlhr" # => /dir/xmlhr.js
# javascript_path "http://www.railsapplication.com/js/xmlhr" # => http://www.railsapplication.com/js/xmlhr
# javascript_path "http://www.railsapplication.com/js/xmlhr.js" # => http://www.railsapplication.com/js/xmlhr.js
def javascript_path(source)
compute_public_path(source, 'javascripts', 'js')
end
alias_method :path_to_javascript, :javascript_path # aliased to avoid conflicts with a javascript_path named route
# Returns an html script tag for each of the +sources+ provided. You
# can pass in the filename (.js extension is optional) of javascript files
# that exist in your public/javascripts directory for inclusion into the
# current page or you can pass the full path relative to your document
# root. To include the Prototype and Scriptaculous javascript libraries in
# your application, pass :defaults as the source. When using
# :defaults, if an application.js file exists in your public
# javascripts directory, it will be included as well. You can modify the
# html attributes of the script tag by passing a hash as the last argument.
#
# ==== Examples
# javascript_include_tag "xmlhr" # =>
#
#
# javascript_include_tag "xmlhr.js" # =>
#
#
# javascript_include_tag "common.javascript", "/elsewhere/cools" # =>
#
#
#
# javascript_include_tag "http://www.railsapplication.com/xmlhr" # =>
#
#
# javascript_include_tag "http://www.railsapplication.com/xmlhr.js" # =>
#
#
# javascript_include_tag :defaults # =>
#
#
# ...
#
#
# * = The application.js file is only referenced if it exists
#
# Though it's not really recommended practice, if you need to extend the default JavaScript set for any reason
# (e.g., you're going to be using a certain .js file in every action), then take a look at the register_javascript_include_default method.
#
# You can also include all javascripts in the javascripts directory using :all as the source:
#
# javascript_include_tag :all # =>
#
#
# ...
#
#
#
#
# Note that the default javascript files will be included first. So Prototype and Scriptaculous are available to
# all subsequently included files.
#
# If you want Rails to search in all the subdirectories under javascripts, you should explicitly set :recursive:
#
# javascript_include_tag :all, :recursive => true
#
# == Caching multiple javascripts into one
#
# You can also cache multiple javascripts into one file, which requires less HTTP connections to download and can better be
# compressed by gzip (leading to faster transfers). Caching will only happen if config.perform_caching
# is set to true (which is the case by default for the Rails production environment, but not for the development
# environment).
#
# ==== Examples
# javascript_include_tag :all, :cache => true # when config.perform_caching is false =>
#
#
# ...
#
#
#
#
# javascript_include_tag :all, :cache => true # when config.perform_caching is true =>
#
#
# javascript_include_tag "prototype", "cart", "checkout", :cache => "shop" # when config.perform_caching is false =>
#
#
#
#
# javascript_include_tag "prototype", "cart", "checkout", :cache => "shop" # when config.perform_caching is true =>
#
#
# The :recursive option is also available for caching:
#
# javascript_include_tag :all, :cache => true, :recursive => true
def javascript_include_tag(*sources)
options = sources.extract_options!.stringify_keys
concat = options.delete("concat")
cache = concat || options.delete("cache")
recursive = options.delete("recursive")
if concat || (config.perform_caching && cache)
joined_javascript_name = (cache == true ? "all" : cache) + ".js"
joined_javascript_path = File.join(joined_javascript_name[/^#{File::SEPARATOR}/] ? config.assets_dir : config.javascripts_dir, joined_javascript_name)
unless config.perform_caching && File.exists?(joined_javascript_path)
write_asset_file_contents(joined_javascript_path, compute_javascript_paths(sources, recursive))
end
javascript_src_tag(joined_javascript_name, options)
else
sources = expand_javascript_sources(sources, recursive)
ensure_javascript_sources!(sources) if cache
sources.collect { |source| javascript_src_tag(source, options) }.join("\n").html_safe
end
end
@@javascript_expansions = { }
# Register one or more javascript files to be included when symbol
# is passed to javascript_include_tag. This method is typically intended
# to be called from plugin initialization to register javascript files
# that the plugin installed in public/javascripts.
#
# ActionView::Helpers::AssetTagHelper.register_javascript_expansion :monkey => ["head", "body", "tail"]
#
# javascript_include_tag :monkey # =>
#
#
#
def self.register_javascript_expansion(expansions)
@@javascript_expansions.merge!(expansions)
end
def self.reset_javascript_expansions #:nodoc:
@@javascript_expansions = {}
end
@@stylesheet_expansions = {}
# Register one or more stylesheet files to be included when symbol
# is passed to stylesheet_link_tag. This method is typically intended
# to be called from plugin initialization to register stylesheet files
# that the plugin installed in public/stylesheets.
#
# ActionView::Helpers::AssetTagHelper.register_stylesheet_expansion :monkey => ["head", "body", "tail"]
#
# stylesheet_link_tag :monkey # =>
#
#
#
def self.register_stylesheet_expansion(expansions)
@@stylesheet_expansions.merge!(expansions)
end
# Computes the path to a stylesheet asset in the public stylesheets directory.
# If the +source+ filename has no extension, .css will be appended (except for explicit URIs).
# Full paths from the document root will be passed through.
# Used internally by +stylesheet_link_tag+ to build the stylesheet path.
#
# ==== Examples
# stylesheet_path "style" # => /stylesheets/style.css
# stylesheet_path "dir/style.css" # => /stylesheets/dir/style.css
# stylesheet_path "/dir/style.css" # => /dir/style.css
# stylesheet_path "http://www.railsapplication.com/css/style" # => http://www.railsapplication.com/css/style
# stylesheet_path "http://www.railsapplication.com/css/style.css" # => http://www.railsapplication.com/css/style.css
def stylesheet_path(source)
compute_public_path(source, 'stylesheets', 'css')
end
alias_method :path_to_stylesheet, :stylesheet_path # aliased to avoid conflicts with a stylesheet_path named route
# Returns a stylesheet link tag for the sources specified as arguments. If
# you don't specify an extension, .css will be appended automatically.
# You can modify the link attributes by passing a hash as the last argument.
#
# ==== Examples
# stylesheet_link_tag "style" # =>
#
#
# stylesheet_link_tag "style.css" # =>
#
#
# stylesheet_link_tag "http://www.railsapplication.com/style.css" # =>
#
#
# stylesheet_link_tag "style", :media => "all" # =>
#
#
# stylesheet_link_tag "style", :media => "print" # =>
#
#
# stylesheet_link_tag "random.styles", "/css/stylish" # =>
#
#
#
# You can also include all styles in the stylesheets directory using :all as the source:
#
# stylesheet_link_tag :all # =>
#
#
#
#
# If you want Rails to search in all the subdirectories under stylesheets, you should explicitly set :recursive:
#
# stylesheet_link_tag :all, :recursive => true
#
# == Caching multiple stylesheets into one
#
# You can also cache multiple stylesheets into one file, which requires less HTTP connections and can better be
# compressed by gzip (leading to faster transfers). Caching will only happen if config.perform_caching
# is set to true (which is the case by default for the Rails production environment, but not for the development
# environment). Examples:
#
# ==== Examples
# stylesheet_link_tag :all, :cache => true # when config.perform_caching is false =>
#
#
#
#
# stylesheet_link_tag :all, :cache => true # when config.perform_caching is true =>
#
#
# stylesheet_link_tag "shop", "cart", "checkout", :cache => "payment" # when config.perform_caching is false =>
#
#
#
#
# stylesheet_link_tag "shop", "cart", "checkout", :cache => "payment" # when config.perform_caching is true =>
#
#
# The :recursive option is also available for caching:
#
# stylesheet_link_tag :all, :cache => true, :recursive => true
#
# To force concatenation (even in development mode) set :concat to true. This is useful if
# you have too many stylesheets for IE to load.
#
# stylesheet_link_tag :all, :concat => true
#
def stylesheet_link_tag(*sources)
options = sources.extract_options!.stringify_keys
concat = options.delete("concat")
cache = concat || options.delete("cache")
recursive = options.delete("recursive")
if concat || (config.perform_caching && cache)
joined_stylesheet_name = (cache == true ? "all" : cache) + ".css"
joined_stylesheet_path = File.join(joined_stylesheet_name[/^#{File::SEPARATOR}/] ? config.assets_dir : config.stylesheets_dir, joined_stylesheet_name)
unless config.perform_caching && File.exists?(joined_stylesheet_path)
write_asset_file_contents(joined_stylesheet_path, compute_stylesheet_paths(sources, recursive))
end
stylesheet_tag(joined_stylesheet_name, options)
else
sources = expand_stylesheet_sources(sources, recursive)
ensure_stylesheet_sources!(sources) if cache
sources.collect { |source| stylesheet_tag(source, options) }.join("\n").html_safe
end
end
# Web browsers cache favicons. If you just throw a favicon.ico into the document
# root of your application and it changes later, clients that have it in their cache
# won't see the update. Using this helper prevents that because it appends an asset ID:
#
# <%= favicon_link_tag %>
#
# generates
#
#
#
# You may specify a different file in the first argument:
#
# <%= favicon_link_tag 'favicon.ico' %>
#
# That's passed to +path_to_image+ as is, so it gives
#
#
#
# The helper accepts an additional options hash where you can override "rel" and "type".
#
# For example, Mobile Safari looks for a different LINK tag, pointing to an image that
# will be used if you add the page to the home screen of an iPod Touch, iPhone, or iPad.
# The following call would generate such a tag:
#
# <%= favicon_link_tag 'mb-icon.png', :rel => 'apple-touch-icon', :type => 'image/png' %>
#
def favicon_link_tag(source='/favicon.ico', options={})
tag('link', {
:rel => 'shortcut icon',
:type => 'image/vnd.microsoft.icon',
:href => path_to_image(source)
}.merge(options.symbolize_keys))
end
# Computes the path to an image asset in the public images directory.
# Full paths from the document root will be passed through.
# Used internally by +image_tag+ to build the image path:
#
# image_path("edit") # => "/images/edit"
# image_path("edit.png") # => "/images/edit.png"
# image_path("icons/edit.png") # => "/images/icons/edit.png"
# image_path("/icons/edit.png") # => "/icons/edit.png"
# image_path("http://www.railsapplication.com/img/edit.png") # => "http://www.railsapplication.com/img/edit.png"
#
# If you have images as application resources this method may conflict with their named routes.
# The alias +path_to_image+ is provided to avoid that. Rails uses the alias internally, and
# plugin authors are encouraged to do so.
def image_path(source)
compute_public_path(source, 'images')
end
alias_method :path_to_image, :image_path # aliased to avoid conflicts with an image_path named route
# Computes the path to a video asset in the public videos directory.
# Full paths from the document root will be passed through.
# Used internally by +video_tag+ to build the video path.
#
# ==== Examples
# video_path("hd") # => /videos/hd
# video_path("hd.avi") # => /videos/hd.avi
# video_path("trailers/hd.avi") # => /videos/trailers/hd.avi
# video_path("/trailers/hd.avi") # => /trailers/hd.avi
# video_path("http://www.railsapplication.com/vid/hd.avi") # => http://www.railsapplication.com/vid/hd.avi
def video_path(source)
compute_public_path(source, 'videos')
end
alias_method :path_to_video, :video_path # aliased to avoid conflicts with a video_path named route
# Computes the path to an audio asset in the public audios directory.
# Full paths from the document root will be passed through.
# Used internally by +audio_tag+ to build the audio path.
#
# ==== Examples
# audio_path("horse") # => /audios/horse
# audio_path("horse.wav") # => /audios/horse.avi
# audio_path("sounds/horse.wav") # => /audios/sounds/horse.avi
# audio_path("/sounds/horse.wav") # => /sounds/horse.avi
# audio_path("http://www.railsapplication.com/sounds/horse.wav") # => http://www.railsapplication.com/sounds/horse.wav
def audio_path(source)
compute_public_path(source, 'audios')
end
alias_method :path_to_audio, :audio_path # aliased to avoid conflicts with an audio_path named route
# Returns an html image tag for the +source+. The +source+ can be a full
# path or a file that exists in your public images directory.
#
# ==== Options
# You can add HTML attributes using the +options+. The +options+ supports
# three additional keys for convenience and conformance:
#
# * :alt - If no alt text is given, the file name part of the
# +source+ is used (capitalized and without the extension)
# * :size - Supplied as "{Width}x{Height}", so "30x45" becomes
# width="30" and height="45". :size will be ignored if the
# value is not in the correct format.
# * :mouseover - Set an alternate image to be used when the onmouseover
# event is fired, and sets the original image to be replaced onmouseout.
# This can be used to implement an easy image toggle that fires on onmouseover.
#
# ==== Examples
# image_tag("icon") # =>
#
# image_tag("icon.png") # =>
#
# image_tag("icon.png", :size => "16x10", :alt => "Edit Entry") # =>
#
# image_tag("/icons/icon.gif", :size => "16x16") # =>
#
# image_tag("/icons/icon.gif", :height => '32', :width => '32') # =>
#
# image_tag("/icons/icon.gif", :class => "menu_icon") # =>
#
# image_tag("mouse.png", :mouseover => "/images/mouse_over.png") # =>
#
# image_tag("mouse.png", :mouseover => image_path("mouse_over.png")) # =>
#
def image_tag(source, options = {})
options.symbolize_keys!
src = options[:src] = path_to_image(source)
unless src =~ /^cid:/
options[:alt] = options.fetch(:alt){ File.basename(src, '.*').capitalize }
end
if size = options.delete(:size)
options[:width], options[:height] = size.split("x") if size =~ %r{^\d+x\d+$}
end
if mouseover = options.delete(:mouseover)
options[:onmouseover] = "this.src='#{path_to_image(mouseover)}'"
options[:onmouseout] = "this.src='#{src}'"
end
tag("img", options)
end
# Returns an html video tag for the +sources+. If +sources+ is a string,
# a single video tag will be returned. If +sources+ is an array, a video
# tag with nested source tags for each source will be returned. The
# +sources+ can be full paths or files that exists in your public videos
# directory.
#
# ==== Options
# You can add HTML attributes using the +options+. The +options+ supports
# two additional keys for convenience and conformance:
#
# * :poster - Set an image (like a screenshot) to be shown
# before the video loads. The path is calculated like the +src+ of +image_tag+.
# * :size - Supplied as "{Width}x{Height}", so "30x45" becomes
# width="30" and height="45". :size will be ignored if the
# value is not in the correct format.
#
# ==== Examples
# video_tag("trailer") # =>
#
# video_tag("trailer.ogg") # =>
#
# video_tag("trailer.ogg", :controls => true, :autobuffer => true) # =>
#
# video_tag("trailer.m4v", :size => "16x10", :poster => "screenshot.png") # =>
#
# video_tag("/trailers/hd.avi", :size => "16x16") # =>
#
# video_tag("/trailers/hd.avi", :height => '32', :width => '32') # =>
#
# video_tag(["trailer.ogg", "trailer.flv"]) # =>
#
# video_tag(["trailer.ogg", "trailer.flv"] :size => "160x120") # =>
#
def video_tag(sources, options = {})
options.symbolize_keys!
options[:poster] = path_to_image(options[:poster]) if options[:poster]
if size = options.delete(:size)
options[:width], options[:height] = size.split("x") if size =~ %r{^\d+x\d+$}
end
if sources.is_a?(Array)
content_tag("video", options) do
sources.map { |source| tag("source", :src => source) }.join.html_safe
end
else
options[:src] = path_to_video(sources)
tag("video", options)
end
end
# Returns an html audio tag for the +source+.
# The +source+ can be full path or file that exists in
# your public audios directory.
#
# ==== Examples
# audio_tag("sound") # =>
#
# audio_tag("sound.wav") # =>
#
# audio_tag("sound.wav", :autoplay => true, :controls => true) # =>
#
def audio_tag(source, options = {})
options.symbolize_keys!
options[:src] = path_to_audio(source)
tag("audio", options)
end
def self.cache_asset_timestamps
@@cache_asset_timestamps
end
# You can enable or disable the asset tag timestamps cache.
# With the cache enabled, the asset tag helper methods will make fewer
# expensive file system calls. However this prevents you from modifying
# any asset files while the server is running.
#
# ActionView::Helpers::AssetTagHelper.cache_asset_timestamps = false
def self.cache_asset_timestamps=(value)
@@cache_asset_timestamps = value
end
@@cache_asset_timestamps = true
private
def rewrite_extension?(source, dir, ext)
source_ext = File.extname(source)[1..-1]
ext && (source_ext.blank? || (ext != source_ext && File.exist?(File.join(config.assets_dir, dir, "#{source}.#{ext}"))))
end
def rewrite_host_and_protocol(source, has_request)
host = compute_asset_host(source)
if has_request && host.present? && !is_uri?(host)
host = "#{controller.request.protocol}#{host}"
end
"#{host}#{source}"
end
# Add the the extension +ext+ if not present. Return full URLs otherwise untouched.
# Prefix with /dir/ if lacking a leading +/+. Account for relative URL
# roots. Rewrite the asset path for cache-busting asset ids. Include
# asset host, if configured, with the correct request protocol.
def compute_public_path(source, dir, ext = nil, include_host = true)
return source if is_uri?(source)
source += ".#{ext}" if rewrite_extension?(source, dir, ext)
source = "/#{dir}/#{source}" unless source[0] == ?/
source = rewrite_asset_path(source, config.asset_path)
has_request = controller.respond_to?(:request)
if has_request && include_host && source !~ %r{^#{controller.config.relative_url_root}/}
source = "#{controller.config.relative_url_root}#{source}"
end
source = rewrite_host_and_protocol(source, has_request) if include_host
source
end
def is_uri?(path)
path =~ %r{^[-a-z]+://|^cid:}
end
# Pick an asset host for this source. Returns +nil+ if no host is set,
# the host if no wildcard is set, the host interpolated with the
# numbers 0-3 if it contains %d (the number is the source hash mod 4),
# or the value returned from invoking the proc if it's a proc or the value from
# invoking call if it's an object responding to call.
def compute_asset_host(source)
if host = config.asset_host
if host.is_a?(Proc) || host.respond_to?(:call)
case host.is_a?(Proc) ? host.arity : host.method(:call).arity
when 2
request = controller.respond_to?(:request) && controller.request
host.call(source, request)
else
host.call(source)
end
else
(host =~ /%d/) ? host % (source.hash % 4) : host
end
end
end
@@asset_timestamps_cache = {}
@@asset_timestamps_cache_guard = Mutex.new
# Use the RAILS_ASSET_ID environment variable or the source's
# modification time as its cache-busting asset id.
def rails_asset_id(source)
if asset_id = ENV["RAILS_ASSET_ID"]
asset_id
else
if @@cache_asset_timestamps && (asset_id = @@asset_timestamps_cache[source])
asset_id
else
path = File.join(config.assets_dir, source)
asset_id = File.exist?(path) ? File.mtime(path).to_i.to_s : ''
if @@cache_asset_timestamps
@@asset_timestamps_cache_guard.synchronize do
@@asset_timestamps_cache[source] = asset_id
end
end
asset_id
end
end
end
# Break out the asset path rewrite in case plugins wish to put the asset id
# someplace other than the query string.
def rewrite_asset_path(source, path = nil)
if path && path.respond_to?(:call)
return path.call(source)
elsif path && path.is_a?(String)
return path % [source]
end
asset_id = rails_asset_id(source)
if asset_id.blank?
source
else
source + "?#{asset_id}"
end
end
def javascript_src_tag(source, options)
content_tag("script", "", { "type" => Mime::JS, "src" => path_to_javascript(source) }.merge(options))
end
def stylesheet_tag(source, options)
tag("link", { "rel" => "stylesheet", "type" => Mime::CSS, "media" => "screen", "href" => html_escape(path_to_stylesheet(source)) }.merge(options), false, false)
end
def compute_javascript_paths(*args)
expand_javascript_sources(*args).collect { |source| compute_public_path(source, 'javascripts', 'js', false) }
end
def compute_stylesheet_paths(*args)
expand_stylesheet_sources(*args).collect { |source| compute_public_path(source, 'stylesheets', 'css', false) }
end
def expand_javascript_sources(sources, recursive = false)
if sources.include?(:all)
all_javascript_files = collect_asset_files(config.javascripts_dir, ('**' if recursive), '*.js')
((determine_source(:defaults, @@javascript_expansions).dup & all_javascript_files) + all_javascript_files).uniq
else
expanded_sources = sources.collect do |source|
determine_source(source, @@javascript_expansions)
end.flatten
expanded_sources << "application" if sources.include?(:defaults) && File.exist?(File.join(config.javascripts_dir, "application.js"))
expanded_sources
end
end
def expand_stylesheet_sources(sources, recursive)
if sources.first == :all
collect_asset_files(config.stylesheets_dir, ('**' if recursive), '*.css')
else
sources.collect do |source|
determine_source(source, @@stylesheet_expansions)
end.flatten
end
end
def determine_source(source, collection)
case source
when Symbol
collection[source] || raise(ArgumentError, "No expansion found for #{source.inspect}")
else
source
end
end
def ensure_stylesheet_sources!(sources)
sources.each do |source|
asset_file_path!(path_to_stylesheet(source))
end
return sources
end
def ensure_javascript_sources!(sources)
sources.each do |source|
asset_file_path!(path_to_javascript(source))
end
return sources
end
def join_asset_file_contents(paths)
paths.collect { |path| File.read(asset_file_path!(path)) }.join("\n\n")
end
def write_asset_file_contents(joined_asset_path, asset_paths)
FileUtils.mkdir_p(File.dirname(joined_asset_path))
File.atomic_write(joined_asset_path) { |cache| cache.write(join_asset_file_contents(asset_paths)) }
# Set mtime to the latest of the combined files to allow for
# consistent ETag without a shared filesystem.
mt = asset_paths.map { |p| File.mtime(asset_file_path(p)) }.max
File.utime(mt, mt, joined_asset_path)
end
def asset_file_path(path)
File.join(config.assets_dir, path.split('?').first)
end
def asset_file_path!(path)
unless is_uri?(path)
absolute_path = asset_file_path(path)
raise(Errno::ENOENT, "Asset file not found at '#{absolute_path}'" ) unless File.exist?(absolute_path)
return absolute_path
end
end
def collect_asset_files(*path)
dir = path.first
Dir[File.join(*path.compact)].collect do |file|
file[-(file.size - dir.size - 1)..-1].sub(/\.\w+$/, '')
end.sort
end
end
end
end
# stylesheet_link_tag("application")
# # =>
#
# === Using asset hosts
#
# By default, Rails links to these assets on the current host in the public
# folder, but you can direct Rails to link to assets from a dedicated asset
# server by setting ActionController::Base.asset_host in the application
# configuration, typically in config/environments/production.rb.
# For example, you'd define assets.example.com to be your asset
# host this way:
#
# ActionController::Base.asset_host = "assets.example.com"
#
# Helpers take that into account:
#
# image_tag("rails.png")
# # => 
# stylesheet_link_tag("application")
# # =>
#
# Browsers typically open at most two simultaneous connections to a single
# host, which means your assets often have to wait for other assets to finish
# downloading. You can alleviate this by using a %d wildcard in the
# +asset_host+. For example, "assets%d.example.com". If that wildcard is
# present Rails distributes asset requests among the corresponding four hosts
# "assets0.example.com", ..., "assets3.example.com". With this trick browsers
# will open eight simultaneous connections rather than two.
#
# image_tag("rails.png")
# # => 
# stylesheet_link_tag("application")
# # =>
#
# To do this, you can either setup four actual hosts, or you can use wildcard
# DNS to CNAME the wildcard to a single asset host. You can read more about
# setting up your DNS CNAME records from your ISP.
#
# Note: This is purely a browser performance optimization and is not meant
# for server load balancing. See http://www.die.net/musings/page_load_time/
# for background.
#
# Alternatively, you can exert more control over the asset host by setting
# +asset_host+ to a proc like this:
#
# ActionController::Base.asset_host = Proc.new { |source|
# "http://assets#{source.hash % 2 + 1}.example.com"
# }
# image_tag("rails.png")
# # => 
# stylesheet_link_tag("application")
# # =>
#
# The example above generates "http://assets1.example.com" and
# "http://assets2.example.com". This option is useful for example if
# you need fewer/more than four hosts, custom host names, etc.
#
# As you see the proc takes a +source+ parameter. That's a string with the
# absolute path of the asset with any extensions and timestamps in place,
# for example "/images/rails.png?1230601161".
#
# ActionController::Base.asset_host = Proc.new { |source|
# if source.starts_with?('/images')
# "http://images.example.com"
# else
# "http://assets.example.com"
# end
# }
# image_tag("rails.png")
# # => 
# stylesheet_link_tag("application")
# # =>
#
# Alternatively you may ask for a second parameter +request+. That one is
# particularly useful for serving assets from an SSL-protected page. The
# example proc below disables asset hosting for HTTPS connections, while
# still sending assets for plain HTTP requests from asset hosts. If you don't
# have SSL certificates for each of the asset hosts this technique allows you
# to avoid warnings in the client about mixed media.
#
# ActionController::Base.asset_host = Proc.new { |source, request|
# if request.ssl?
# "#{request.protocol}#{request.host_with_port}"
# else
# "#{request.protocol}assets.example.com"
# end
# }
#
# You can also implement a custom asset host object that responds to +call+
# and takes either one or two parameters just like the proc.
#
# config.action_controller.asset_host = AssetHostingWithMinimumSsl.new(
# "http://asset%d.example.com", "https://asset1.example.com"
# )
#
# === Customizing the asset path
#
# By default, Rails appends asset's timestamps to all asset paths. This allows
# you to set a cache-expiration date for the asset far into the future, but
# still be able to instantly invalidate it by simply updating the file (and
# hence updating the timestamp, which then updates the URL as the timestamp
# is part of that, which in turn busts the cache).
#
# It's the responsibility of the web server you use to set the far-future
# expiration date on cache assets that you need to take advantage of this
# feature. Here's an example for Apache:
#
# # Asset Expiration
# ExpiresActive On
# 
# stylesheet_link_tag("application")
# # =>
#
# Changing the asset_path does require that your web servers have
# knowledge of the asset template paths that you rewrite to so it's not
# suitable for out-of-the-box use. To use the example given above you
# could use something like this in your Apache VirtualHost configuration:
#
# 
# image_tag("icon.png") # =>
# 
# image_tag("icon.png", :size => "16x10", :alt => "Edit Entry") # =>
# 
# image_tag("/icons/icon.gif", :height => '32', :width => '32') # =>
# 
# image_tag("mouse.png", :mouseover => image_path("mouse_over.png")) # =>
#