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.

Instance Method Summary collapse

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" />



21
22
23
24
25
26
27
28
29
 
# 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”



102
103
104
 
# File 'lib/action_view/helpers/asset_tag_helper.rb', line 102

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”



115
116
117
118
119
120
121
122
123
124
125
126
127
 
# File 'lib/action_view/helpers/asset_tag_helper.rb', line 115

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/scriptaculous.js"></script>
  <script type="text/javascript" src="/javascripts/application.js"></script> *see beloe

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.



56
57
58
59
60
61
62
63
64
65
66
67
68
 
# File 'lib/action_view/helpers/asset_tag_helper.rb', line 56

def javascript_include_tag(*sources)
  options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }
  if sources.first == :defaults
    sources = ['prototype', 'scriptaculous']
    if defined?(RAILS_ROOT) and File.exists?("#{RAILS_ROOT}/public/javascripts/application.js")
      sources << 'application' 
    end
  end
  sources.collect { |source|
    source = javascript_path(source)        
    content_tag("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



34
35
36
 
# File 'lib/action_view/helpers/asset_tag_helper.rb', line 34

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

#stylesheet_link_tag(*sources) ⇒ Object

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" />



88
89
90
91
92
93
94
 
# File 'lib/action_view/helpers/asset_tag_helper.rb', line 88

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



73
74
75
 
# File 'lib/action_view/helpers/asset_tag_helper.rb', line 73

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