Module: ActionView::Helpers::AssetTagHelper

Defined in:
lib/action_view/helpers/asset_tag_helper.rb

Overview

Provides methods for linking a HTML page together with other assets, such as javascripts, stylesheets, and feeds.

Constant Summary collapse

JAVASCRIPT_DEFAULT_SOURCES =
['prototype', 'effects', 'dragdrop', 'controls']
@@javascript_default_sources =
JAVASCRIPT_DEFAULT_SOURCES.dup

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.register_javascript_include_default(*sources) ⇒ Object

Register one or more additional JavaScript files to be included when

javascript_include_tag :defaults

is called. This method is intended to be called only from plugin initialization to register extra .js files the plugin installed in public/javascripts.


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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 84

def self.register_javascript_include_default(*sources)
  @@javascript_default_sources.concat(sources)
end

.reset_javascript_include_defaultObject

:nodoc:


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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 88

def self.reset_javascript_include_default #:nodoc:
  @@javascript_default_sources = JAVASCRIPT_DEFAULT_SOURCES.dup
end

Instance Method Details

Returns a link tag that browsers and news readers can use to auto-detect a RSS or ATOM feed for this page. The type can either be :rss (default) or :atom and the options follow the url_for style of declaring a link target.

Examples:

auto_discovery_link_tag # =>
  <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.curenthost.com/controller/action" />
auto_discovery_link_tag(:atom) # =>
  <link rel="alternate" type="application/atom+xml" title="ATOM" href="http://www.curenthost.com/controller/action" />
auto_discovery_link_tag(:rss, {:action => "feed"}) # =>
  <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.curenthost.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.curenthost.com/controller/feed" />

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 21

def auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})
  tag(
    "link", 
    "rel"   => tag_options[:rel] || "alternate",
    "type"  => tag_options[:type] || "application/#{type}+xml",
    "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

#image_path(source) ⇒ Object

Returns path to an image asset. Example:

The src can be supplied as a…

  • full path, like “/my_images/image.gif”

  • file name, like “rss.gif”, that gets expanded to “/images/rss.gif”

  • file name without extension, like “logo”, that gets expanded to “/images/logo.png”


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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 124

def image_path(source)
  compute_public_path(source, 'images', 'png')
end

#image_tag(source, options = {}) ⇒ Object

Returns an image tag converting the options into html options on the tag, but with these special cases:

  • :alt - If no alt text is given, the file name part of the src is used (capitalized and without the extension)

  • :size - Supplied as “XxY”, so “30x45” becomes width=“30” and height=“45”

The src can be supplied as a…

  • full path, like “/my_images/image.gif”

  • file name, like “rss.gif”, that gets expanded to “/images/rss.gif”

  • file name without extension, like “logo”, that gets expanded to “/images/logo.png”


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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 137

def image_tag(source, options = {})
  options.symbolize_keys!
          
  options[:src] = image_path(source)
  options[:alt] ||= File.basename(options[:src], '.*').split('.').first.capitalize
  
  if options[:size]
    options[:width], options[:height] = options[:size].split("x")
    options.delete :size
  end

  tag("img", options)
end

#javascript_include_tag(*sources) ⇒ Object

Returns a script include tag per source given as argument. Examples:

javascript_include_tag "xmlhr" # =>
  <script type="text/javascript" src="/javascripts/xmlhr.js"></script>

javascript_include_tag "common.javascript", "/elsewhere/cools" # =>
  <script type="text/javascript" src="/javascripts/common.javascript"></script>
  <script type="text/javascript" src="/elsewhere/cools.js"></script>

javascript_include_tag :defaults # =>
  <script type="text/javascript" src="/javascripts/prototype.js"></script>
  <script type="text/javascript" src="/javascripts/effects.js"></script>
  ...
  <script type="text/javascript" src="/javascripts/application.js"></script> *see below

If there's an application.js file in your public/javascripts directory, javascript_include_tag :defaults will automatically include it. This file facilitates the inclusion of small snippets of JavaScript code, along the lines of controllers/application.rb and helpers/application_helper.rb.


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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 60

def javascript_include_tag(*sources)
  options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }

  if sources.include?(:defaults) 
    sources = sources[0..(sources.index(:defaults))] + 
      @@javascript_default_sources.dup + 
      sources[(sources.index(:defaults) + 1)..sources.length]

    sources.delete(:defaults) 
    sources << "application" if defined?(RAILS_ROOT) && File.exists?("#{RAILS_ROOT}/public/javascripts/application.js") 
  end

  sources.collect { |source|
    source = javascript_path(source)        
    ("script", "", { "type" => "text/javascript", "src" => source }.merge(options))
  }.join("\n")
end

#javascript_path(source) ⇒ Object

Returns path to a javascript asset. Example:

javascript_path "xmlhr" # => /javascripts/xmlhr.js

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 34

def javascript_path(source)
  compute_public_path(source, 'javascripts', 'js')        
end

Returns a css link tag per source given as argument. Examples:

stylesheet_link_tag "style" # =>
  <link href="/stylesheets/style.css" media="screen" rel="Stylesheet" type="text/css" />

stylesheet_link_tag "style", :media => "all" # =>
  <link href="/stylesheets/style.css" media="all" rel="Stylesheet" type="text/css" />

stylesheet_link_tag "random.styles", "/css/stylish" # =>
  <link href="/stylesheets/random.styles" media="screen" rel="Stylesheet" type="text/css" />
  <link href="/css/stylish.css" media="screen" rel="Stylesheet" type="text/css" />

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 110

def stylesheet_link_tag(*sources)
  options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }
  sources.collect { |source|
    source = stylesheet_path(source)
    tag("link", { "rel" => "Stylesheet", "type" => "text/css", "media" => "screen", "href" => source }.merge(options))
  }.join("\n")
end

#stylesheet_path(source) ⇒ Object

Returns path to a stylesheet asset. Example:

stylesheet_path "style" # => /stylesheets/style.css

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 95

def stylesheet_path(source)
  compute_public_path(source, 'stylesheets', 'css')
end