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require 'action_view/helpers/asset_tag_helpers/javascript_tag_helpers'
require 'action_view/helpers/asset_tag_helpers/stylesheet_tag_helpers'
require 'action_view/helpers/asset_tag_helpers/asset_paths'
require 'action_view/helpers/tag_helper'
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")
# # => <img alt="Rails" src="/images/rails.png?1230601161" />
# stylesheet_link_tag("application")
# # => <link href="/stylesheets/application.css?1232285206" media="screen" rel="stylesheet" type="text/css" />
#
# === 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 <tt>config/environments/production.rb</tt>.
# For example, you'd define <tt>assets.example.com</tt> to be your asset
# host this way:
#
# ActionController::Base.asset_host = "assets.example.com"
#
# Helpers take that into account:
#
# image_tag("rails.png")
# # => <img alt="Rails" src="http://assets.example.com/images/rails.png?1230601161" />
# stylesheet_link_tag("application")
# # => <link href="http://assets.example.com/stylesheets/application.css?1232285206" media="screen" rel="stylesheet" type="text/css" />
#
# 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 <tt>%d</tt> 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")
# # => <img alt="Rails" src="http://assets0.example.com/images/rails.png?1230601161" />
# stylesheet_link_tag("application")
# # => <link href="http://assets2.example.com/stylesheets/application.css?1232285206" media="screen" rel="stylesheet" type="text/css" />
#
# 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#{Digest::MD5.hexdigest(source).to_i(16) % 2 + 1}.example.com"
# }
# image_tag("rails.png")
# # => <img alt="Rails" src="http://assets1.example.com/images/rails.png?1230601161" />
# stylesheet_link_tag("application")
# # => <link href="http://assets2.example.com/stylesheets/application.css?1232285206" media="screen" rel="stylesheet" type="text/css" />
#
# 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")
# # => <img alt="Rails" src="http://images.example.com/images/rails.png?1230601161" />
# stylesheet_link_tag("application")
# # => <link href="http://assets.example.com/stylesheets/application.css?1232285206" media="screen" rel="stylesheet" type="text/css" />
#
# 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
# <FilesMatch "\.(ico|gif|jpe?g|png|js|css)$">
# ExpiresDefault "access plus 1 year"
# </FilesMatch>
#
# 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
# <tt>ActionController::Base.config.asset_path</tt> 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
# <tt>config/environments/production.rb</tt>:
#
# # Normally you'd calculate RELEASE_NUMBER at startup.
# RELEASE_NUMBER = 12345
# config.action_controller.asset_path = proc { |asset_path|
# "/release-#{RELEASE_NUMBER}#{asset_path}"
# }
#
# This example would cause the following behavior on all servers no
# matter when they were deployed:
#
# image_tag("rails.png")
# # => <img alt="Rails" src="/release-12345/images/rails.png" />
# stylesheet_link_tag("application")
# # => <link href="/release-12345/stylesheets/application.css?1232285206" media="screen" rel="stylesheet" type="text/css" />
#
# 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:
#
# <LocationMatch "^/release-\d+/(images|javascripts|stylesheets)/.*$">
# # 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"
# </LocationMatch>
#
# # 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
include TagHelper
include JavascriptTagHelpers
include StylesheetTagHelpers
# Returns a link tag that browsers and news readers can use to auto-detect
# an RSS or ATOM feed. The +type+ can either be <tt>:rss</tt> (default) or
# <tt>:atom</tt>. Control the link options in url_for format using the
# +url_options+. You can modify the LINK tag itself in +tag_options+.
#
# ==== Options
# * <tt>:rel</tt> - Specify the relation of this link, defaults to "alternate"
# * <tt>:type</tt> - Override the auto-generated mime type
# * <tt>:title</tt> - Specify the title of the link, defaults to the +type+
#
# ==== Examples
# auto_discovery_link_tag # =>
# <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.currenthost.com/controller/action" />
# auto_discovery_link_tag(:atom) # =>
# <link rel="alternate" type="application/atom+xml" title="ATOM" href="http://www.currenthost.com/controller/action" />
# auto_discovery_link_tag(:rss, {:action => "feed"}) # =>
# <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.currenthost.com/controller/feed" />
# auto_discovery_link_tag(:rss, {:action => "feed"}, {:title => "My RSS"}) # =>
# <link rel="alternate" type="application/rss+xml" title="My RSS" href="http://www.currenthost.com/controller/feed" />
# auto_discovery_link_tag(:rss, {:controller => "news", :action => "feed"}) # =>
# <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.currenthost.com/news/feed" />
# auto_discovery_link_tag(:rss, "http://www.example.com/feed.rss", {:title => "Example RSS"}) # =>
# <link rel="alternate" type="application/rss+xml" title="Example RSS" href="http://www.example.com/feed" />
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
# Web browsers cache favicons. If you just throw a <tt>favicon.ico</tt> 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
#
# <link href="/favicon.ico?4649789979" rel="shortcut icon" type="image/vnd.microsoft.icon" />
#
# 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
#
# <link href="/images/favicon.ico?4649789979" rel="shortcut icon" type="image/vnd.microsoft.icon" />
#
# 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.example.com/img/edit.png") # => "http://www.example.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)
asset_paths.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.example.com/vid/hd.avi") # => http://www.example.com/vid/hd.avi
def video_path(source)
asset_paths.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.wav
# audio_path("sounds/horse.wav") # => /audios/sounds/horse.wav
# audio_path("/sounds/horse.wav") # => /sounds/horse.wav
# audio_path("http://www.example.com/sounds/horse.wav") # => http://www.example.com/sounds/horse.wav
def audio_path(source)
asset_paths.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:
#
# * <tt>:alt</tt> - If no alt text is given, the file name part of the
# +source+ is used (capitalized and without the extension)
# * <tt>:size</tt> - Supplied as "{Width}x{Height}", so "30x45" becomes
# width="30" and height="45". <tt>:size</tt> will be ignored if the
# value is not in the correct format.
# * <tt>:mouseover</tt> - 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") # =>
# <img src="/images/icon" alt="Icon" />
# image_tag("icon.png") # =>
# <img src="/images/icon.png" alt="Icon" />
# image_tag("icon.png", :size => "16x10", :alt => "Edit Entry") # =>
# <img src="/images/icon.png" width="16" height="10" alt="Edit Entry" />
# image_tag("/icons/icon.gif", :size => "16x16") # =>
# <img src="/icons/icon.gif" width="16" height="16" alt="Icon" />
# image_tag("/icons/icon.gif", :height => '32', :width => '32') # =>
# <img alt="Icon" height="32" src="/icons/icon.gif" width="32" />
# image_tag("/icons/icon.gif", :class => "menu_icon") # =>
# <img alt="Icon" class="menu_icon" src="/icons/icon.gif" />
# image_tag("mouse.png", :mouseover => "/images/mouse_over.png") # =>
# <img src="/images/mouse.png" onmouseover="this.src='/images/mouse_over.png'" onmouseout="this.src='/images/mouse.png'" alt="Mouse" />
# image_tag("mouse.png", :mouseover => image_path("mouse_over.png")) # =>
# <img src="/images/mouse.png" onmouseover="this.src='/images/mouse_over.png'" onmouseout="this.src='/images/mouse.png'" alt="Mouse" />
def image_tag(source, options = {})
options.symbolize_keys!
src = options[:src] = path_to_image(source)
unless src =~ /^(?:cid|data):/
options[:alt] = options.fetch(:alt){ image_alt(src) }
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
def image_alt(src)
File.basename(src, '.*').sub(/-[[:xdigit:]]{32}\z/, '').capitalize
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:
#
# * <tt>:poster</tt> - Set an image (like a screenshot) to be shown
# before the video loads. The path is calculated like the +src+ of +image_tag+.
# * <tt>:size</tt> - Supplied as "{Width}x{Height}", so "30x45" becomes
# width="30" and height="45". <tt>:size</tt> will be ignored if the
# value is not in the correct format.
#
# ==== Examples
# video_tag("trailer") # =>
# <video src="/videos/trailer" />
# video_tag("trailer.ogg") # =>
# <video src="/videos/trailer.ogg" />
# video_tag("trailer.ogg", :controls => true, :autobuffer => true) # =>
# <video autobuffer="autobuffer" controls="controls" src="/videos/trailer.ogg" />
# video_tag("trailer.m4v", :size => "16x10", :poster => "screenshot.png") # =>
# <video src="/videos/trailer.m4v" width="16" height="10" poster="/images/screenshot.png" />
# video_tag("/trailers/hd.avi", :size => "16x16") # =>
# <video src="/trailers/hd.avi" width="16" height="16" />
# video_tag("/trailers/hd.avi", :height => '32', :width => '32') # =>
# <video height="32" src="/trailers/hd.avi" width="32" />
# video_tag(["trailer.ogg", "trailer.flv"]) # =>
# <video><source src="trailer.ogg" /><source src="trailer.ogg" /><source src="trailer.flv" /></video>
# video_tag(["trailer.ogg", "trailer.flv"] :size => "160x120") # =>
# <video height="120" width="160"><source src="trailer.ogg" /><source src="trailer.flv" /></video>
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 src="/audios/sound" />
# audio_tag("sound.wav") # =>
# <audio src="/audios/sound.wav" />
# audio_tag("sound.wav", :autoplay => true, :controls => true) # =>
# <audio autoplay="autoplay" controls="controls" src="/audios/sound.wav" />
def audio_tag(source, options = {})
options.symbolize_keys!
options[:src] = path_to_audio(source)
tag("audio", options)
end
private
def asset_paths
@asset_paths ||= AssetTagHelper::AssetPaths.new(config, controller)
end
end
end
end
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