require 'cgi' require 'action_view/helpers/url_helper' require 'action_view/helpers/tag_helper' module ActionView 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. # # === 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 assets server by # setting ActionController::Base.asset_host in your config/environment.rb. For example, # let's say your asset host is assets.example.com. # # ActionController::Base.asset_host = "assets.example.com" # image_tag("rails.png") # => Rails # stylesheet_link_tag("application") # => # # This is useful since browsers typically open at most two connections to a single host, # which means your assets often wait in single file for their turn to load. You can # alleviate this by using a %d wildcard in asset_host (for example, "assets%d.example.com") # to automatically distribute asset requests among four hosts (e.g., "assets0.example.com" through "assets3.example.com") # so browsers will open eight connections rather than two. # # image_tag("rails.png") # => Rails # stylesheet_link_tag("application") # => # # To do this, you can either setup 4 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 # that takes a single source argument. This is useful if you are unable to setup 4 actual hosts or have # fewer/more than 4 hosts. The example proc below generates http://assets1.example.com and # http://assets2.example.com randomly. # # ActionController::Base.asset_host = Proc.new { |source| "http://assets#{rand(2) + 1}.example.com" } # image_tag("rails.png") # => Rails # stylesheet_link_tag("application") # => # # The proc takes a source parameter (which is the path of the source asset) and an optional # request parameter (which is an entire instance of an ActionController::AbstractRequest # subclass). This can be used to generate a particular asset host depending on the asset path and the particular # request. # # 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") # => Rails # stylesheet_link_tag("application") # => # # The optional request parameter to the proc is useful in particular 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. This is useful for avoiding mixed media warnings when serving # non-HTTP assets from HTTPS web pages when you don't have an SSL certificate for each of the asset hosts. # # ActionController::Base.asset_host = Proc.new { |source, request| # if request.ssl? # "#{request.protocol}#{request.host_with_port}" # else # "#{request.protocol}assets.example.com" # end # } # # === Using asset timestamps # # By default, Rails will append all asset paths with that asset's timestamp. 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 drift out of sync, you'll see different timestamps at random and the cache won't # work. Which means that 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 (and that the assets are not being # requested over and over). module AssetTagHelper ASSETS_DIR = defined?(Rails.public_path) ? Rails.public_path : "public" JAVASCRIPTS_DIR = "#{ASSETS_DIR}/javascripts" STYLESHEETS_DIR = "#{ASSETS_DIR}/stylesheets" # 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. # 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.js # 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 JAVASCRIPT_DEFAULT_SOURCES = ['prototype', 'effects', 'dragdrop', 'controls'] unless const_defined?(:JAVASCRIPT_DEFAULT_SOURCES) @@javascript_expansions = { :defaults => JAVASCRIPT_DEFAULT_SOURCES.dup } @@stylesheet_expansions = {} # 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. # # == 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 ActionController::Base.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 ActionController::Base.perform_caching is false => # # # ... # # # # # javascript_include_tag :all, :cache => true # when ActionController::Base.perform_caching is true => # # # javascript_include_tag "prototype", "cart", "checkout", :cache => "shop" # when ActionController::Base.perform_caching is false => # # # # # javascript_include_tag "prototype", "cart", "checkout", :cache => "shop" # when ActionController::Base.perform_caching is true => # def javascript_include_tag(*sources) options = sources.extract_options!.stringify_keys cache = options.delete("cache") if ActionController::Base.perform_caching && cache joined_javascript_name = (cache == true ? "all" : cache) + ".js" joined_javascript_path = File.join(JAVASCRIPTS_DIR, joined_javascript_name) write_asset_file_contents(joined_javascript_path, compute_javascript_paths(sources)) javascript_src_tag(joined_javascript_name, options) else expand_javascript_sources(sources).collect { |source| javascript_src_tag(source, options) }.join("\n") end end # 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 # 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 # Register one or more additional JavaScript files to be included when # javascript_include_tag :defaults is called. This method is # typically intended to be called from plugin initialization to register additional # .js files that the plugin installed in public/javascripts. def self.register_javascript_include_default(*sources) @@javascript_expansions[:defaults].concat(sources) end def self.reset_javascript_include_default #:nodoc: @@javascript_expansions[:defaults] = JAVASCRIPT_DEFAULT_SOURCES.dup end # Computes the path to a stylesheet asset in the public stylesheets directory. # If the +source+ filename has no extension, .css will be appended. # 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.css # stylesheet_path "http://www.railsapplication.com/css/style.js" # => 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 stylesheet directory using :all as the source: # # stylesheet_link_tag :all # => # # # # # == 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 ActionController::Base.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 ActionController::Base.perform_caching is false => # # # # # stylesheet_link_tag :all, :cache => true # when ActionController::Base.perform_caching is true => # # # stylesheet_link_tag "shop", "cart", "checkout", :cache => "payment" # when ActionController::Base.perform_caching is false => # # # # # stylesheet_link_tag "shop", "cart", "checkout", :cache => "payment" # when ActionController::Base.perform_caching is true => # def stylesheet_link_tag(*sources) options = sources.extract_options!.stringify_keys cache = options.delete("cache") if ActionController::Base.perform_caching && cache joined_stylesheet_name = (cache == true ? "all" : cache) + ".css" joined_stylesheet_path = File.join(STYLESHEETS_DIR, joined_stylesheet_name) write_asset_file_contents(joined_stylesheet_path, compute_stylesheet_paths(sources)) stylesheet_tag(joined_stylesheet_name, options) else expand_stylesheet_sources(sources).collect { |source| stylesheet_tag(source, options) }.join("\n") end 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. # # ==== Examples # 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 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 # 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") # => # Icon # image_tag("icon.png") # => # Icon # image_tag("icon.png", :size => "16x10", :alt => "Edit Entry") # => # Edit Entry # image_tag("/icons/icon.gif", :size => "16x16") # => # Icon # image_tag("/icons/icon.gif", :height => '32', :width => '32') # => # Icon # image_tag("/icons/icon.gif", :class => "menu_icon") # => # Icon # image_tag("mouse.png", :mouseover => "/images/mouse_over.png") # => # Mouse # image_tag("mouse.png", :mouseover => image_path("mouse_over.png")) # => # Mouse def image_tag(source, options = {}) options.symbolize_keys! options[:src] = path_to_image(source) options[:alt] ||= File.basename(options[:src], '.*').split('.').first.to_s.capitalize 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='#{image_path(mouseover)}'" options[:onmouseout] = "this.src='#{image_path(options[:src])}'" end tag("img", options) end private def file_exist?(path) @@file_exist_cache ||= {} if !(@@file_exist_cache[path] ||= File.exist?(path)) @@file_exist_cache[path] = true false else true end 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) has_request = @controller.respond_to?(:request) cache_key = if has_request [ @controller.request.protocol, ActionController::Base.asset_host.to_s, @controller.request.relative_url_root, dir, source, ext, include_host ].join else [ ActionController::Base.asset_host.to_s, dir, source, ext, include_host ].join end ActionView::Base.computed_public_paths[cache_key] ||= begin source += ".#{ext}" if ext && File.extname(source).blank? || File.exist?(File.join(ASSETS_DIR, dir, "#{source}.#{ext}")) if source =~ %r{^[-a-z]+://} source else source = "/#{dir}/#{source}" unless source[0] == ?/ if has_request unless source =~ %r{^#{@controller.request.relative_url_root}/} source = "#{@controller.request.relative_url_root}#{source}" end end source = rewrite_asset_path(source) if include_host host = compute_asset_host(source) if has_request && !host.blank? && host !~ %r{^[-a-z]+://} host = "#{@controller.request.protocol}#{host}" end "#{host}#{source}" else source end end end 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. def compute_asset_host(source) if host = ActionController::Base.asset_host if host.is_a?(Proc) case host.arity when 2 host.call(source, @controller.request) else host.call(source) end else (host =~ /%d/) ? host % (source.hash % 4) : host end end end # 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 path = File.join(ASSETS_DIR, source) if File.exist?(path) File.mtime(path).to_i.to_s else '' 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) 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(sources) expand_javascript_sources(sources).collect { |source| compute_public_path(source, 'javascripts', 'js', false) } end def compute_stylesheet_paths(sources) expand_stylesheet_sources(sources).collect { |source| compute_public_path(source, 'stylesheets', 'css', false) } end def expand_javascript_sources(sources) if sources.include?(:all) all_javascript_files = Dir[File.join(JAVASCRIPTS_DIR, '*.js')].collect { |file| File.basename(file).gsub(/\.\w+$/, '') }.sort @@all_javascript_sources ||= ((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(JAVASCRIPTS_DIR, "application.js")) expanded_sources end end def expand_stylesheet_sources(sources) if sources.first == :all @@all_stylesheet_sources ||= Dir[File.join(STYLESHEETS_DIR, '*.css')].collect { |file| File.basename(file).gsub(/\.\w+$/, '') }.sort 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 join_asset_file_contents(paths) paths.collect { |path| File.read(File.join(ASSETS_DIR, path.split("?").first)) }.join("\n\n") end def write_asset_file_contents(joined_asset_path, asset_paths) unless file_exist?(joined_asset_path) FileUtils.mkdir_p(File.dirname(joined_asset_path)) File.open(joined_asset_path, "w+") { |cache| cache.write(join_asset_file_contents(asset_paths)) } end end end end end