Module ActionView::Helpers::AssetTagHelper
In: vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb

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

Methods

Constants

JAVASCRIPT_DEFAULT_SOURCES = ['prototype', 'effects', 'dragdrop', 'controls'] unless const_defined?(:JAVASCRIPT_DEFAULT_SOURCES)

Public Class methods

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.

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 84
84:       def self.register_javascript_include_default(*sources)
85:         @@javascript_default_sources.concat(sources)
86:       end

Public Instance methods

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" />

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 21
21:       def auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})
22:         tag(
23:           "link", 
24:           "rel"   => tag_options[:rel] || "alternate",
25:           "type"  => tag_options[:type] || "application/#{type}+xml",
26:           "title" => tag_options[:title] || type.to_s.upcase,
27:           "href"  => url_options.is_a?(Hash) ? url_for(url_options.merge(:only_path => false)) : url_options
28:         )
29:       end

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"

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 124
124:       def image_path(source)
125:         compute_public_path(source, 'images', 'png')
126:       end

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"

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 137
137:       def image_tag(source, options = {})
138:         options.symbolize_keys!
139:                 
140:         options[:src] = image_path(source)
141:         options[:alt] ||= File.basename(options[:src], '.*').split('.').first.capitalize
142:         
143:         if options[:size]
144:           options[:width], options[:height] = options[:size].split("x")
145:           options.delete :size
146:         end
147: 
148:         tag("img", options)
149:       end

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.

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 60
60:       def javascript_include_tag(*sources)
61:         options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }
62: 
63:         if sources.include?(:defaults) 
64:           sources = sources[0..(sources.index(:defaults))] + 
65:             @@javascript_default_sources.dup + 
66:             sources[(sources.index(:defaults) + 1)..sources.length]
67: 
68:           sources.delete(:defaults) 
69:           sources << "application" if defined?(RAILS_ROOT) && File.exists?("#{RAILS_ROOT}/public/javascripts/application.js") 
70:         end
71: 
72:         sources.collect { |source|
73:           source = javascript_path(source)        
74:           content_tag("script", "", { "type" => "text/javascript", "src" => source }.merge(options))
75:         }.join("\n")
76:       end

Returns path to a javascript asset. Example:

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

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 34
34:       def javascript_path(source)
35:         compute_public_path(source, 'javascripts', 'js')        
36:       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" />

[Source]

     # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 110
110:       def stylesheet_link_tag(*sources)
111:         options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }
112:         sources.collect { |source|
113:           source = stylesheet_path(source)
114:           tag("link", { "rel" => "Stylesheet", "type" => "text/css", "media" => "screen", "href" => source }.merge(options))
115:         }.join("\n")
116:       end

Returns path to a stylesheet asset. Example:

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

[Source]

    # File vendor/rails/actionpack/lib/action_view/helpers/asset_tag_helper.rb, line 95
95:       def stylesheet_path(source)
96:         compute_public_path(source, 'stylesheets', 'css')
97:       end

[Validate]