Module: ActionView::Helpers::AssetTagHelper

Extended by:
ActiveSupport::Concern
Includes:
AssetUrlHelper, TagHelper
Included in:
ActionView::Helpers
Defined in:
lib/action_view/helpers/asset_tag_helper.rb

Overview

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="/assets/rails.png" />
stylesheet_link_tag("application")
# => <link href="/assets/application.css?body=1" media="screen" rel="stylesheet" />

Constant Summary

Constants included from TagHelper

TagHelper::BOOLEAN_ATTRIBUTES, TagHelper::PRE_CONTENT_STRINGS

Constants included from AssetUrlHelper

ActionView::Helpers::AssetUrlHelper::ASSET_EXTENSIONS, ActionView::Helpers::AssetUrlHelper::ASSET_PUBLIC_DIRECTORIES, ActionView::Helpers::AssetUrlHelper::URI_REGEXP

Instance Method Summary collapse

Methods included from TagHelper

#cdata_section, #content_tag, #escape_once, #tag

Methods included from CaptureHelper

#capture, #content_for, #content_for?, #flush_output_buffer, #provide, #with_output_buffer

Methods included from AssetUrlHelper

#asset_path, #asset_url, #audio_path, #audio_url, #compute_asset_extname, #compute_asset_host, #compute_asset_path, #font_path, #font_url, #image_path, #image_url, #javascript_path, #javascript_url, #stylesheet_path, #stylesheet_url, #video_path, #video_url

Instance Method Details

#audio_tag(*sources) ⇒ Object

Returns an HTML audio tag for the source. The source can be full path or file that exists in your public audios directory.

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" />
audio_tag("sound.wav", "sound.mid")
# => <audio><source src="/audios/sound.wav" /><source src="/audios/sound.mid" /></audio>

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 298

def audio_tag(*sources)
  multiple_sources_tag('audio', sources)
end

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
# => <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" />

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 128

def auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})
  if !(type == :rss || type == :atom) && tag_options[:type].blank?
    message = "You have passed type other than :rss or :atom to auto_discovery_link_tag and haven't supplied " +
              "the :type option key. This behavior is deprecated and will be remove in Rails 4.1. You should pass " +
              ":type option explicitly if you want to use other types, for example: " +
              "auto_discovery_link_tag(:xml, '/feed.xml', :type => 'application/xml')"
    ActiveSupport::Deprecation.warn message
  end

  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

Returns a link loading a favicon file. You may specify a different file in the first argument. The helper accepts an additional options hash where you can override “rel” and “type”.

Options

  • :rel - Specify the relation of this link, defaults to 'shortcut icon'

  • :type - Override the auto-generated mime type, defaults to 'image/vnd.microsoft.icon'

Examples

favicon_link_tag '/myicon.ico'
# => <link href="/assets/favicon.ico" rel="shortcut icon" type="image/vnd.microsoft.icon" />

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'
# => <link href="/assets/mb-icon.png" rel="apple-touch-icon" type="image/png" />

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 166

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

#image_alt(src) ⇒ Object

Returns a string suitable for an html image tag alt attribute. The src argument is meant to be an image file path. The method removes the basename of the file path and the digest, if any. It also removes hyphens and underscores from file names and replaces them with spaces, returning a space-separated, titleized string.

Examples

image_tag('rails.png')
# => <img alt="Rails" src="/assets/rails.png" />

image_tag('hyphenated-file-name.png')
# => <img alt="Hyphenated file name" src="/assets/hyphenated-file-name.png" />

image_tag('underscored_file_name.png')
# => <img alt="Underscored file name" src="/assets/underscored_file_name.png" />

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 236

def image_alt(src)
  File.basename(src, '.*').sub(/-[[:xdigit:]]{32}\z/, '').tr('-_', ' ').capitalize
end

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

Returns an HTML image tag for the source. The source can be a full path or a file.

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 “WidthxHeight” or “Number”, so “30x45” becomes width=“30” and height=“45”, and “50” becomes width=“50” and height=“50”. :size will be ignored if the value is not in the correct format.

Examples

image_tag("icon")
# => <img alt="Icon" src="/assets/icon" />
image_tag("icon.png")
# => <img alt="Icon" src="/assets/icon.png" />
image_tag("icon.png", size: "16x10", alt: "Edit Entry")
# => <img src="/assets/icon.png" width="16" height="10" alt="Edit Entry" />
image_tag("/icons/icon.gif", size: "16")
# => <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" />

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 202

def image_tag(source, options={})
  options = options.symbolize_keys

  src = options[:src] = path_to_image(source)

  unless src =~ /^(?:cid|data):/ || src.blank?
    options[:alt] = options.fetch(:alt){ image_alt(src) }
  end

  if size = options.delete(:size)
    options[:width], options[:height] = size.split("x") if size =~ %r{\A\d+x\d+\z}
    options[:width] = options[:height] = size if size =~ %r{\A\d+\z}
  end

  tag("img", options)
end

#javascript_include_tag(*sources) ⇒ Object

Returns an HTML script tag for each of the sources provided.

Sources may be paths to JavaScript files. Relative paths are assumed to be relative to assets/javascripts, full paths are assumed to be relative to the document root. Relative paths are idiomatic, use absolute paths only when needed.

When passing paths, the “.js” extension is optional.

You can modify the HTML attributes of the script tag by passing a hash as the last argument.

When the Asset Pipeline is enabled, you can pass the name of your manifest as source, and include other JavaScript or CoffeeScript files inside the manifest.

javascript_include_tag "xmlhr"
# => <script src="/assets/xmlhr.js?1284139606"></script>

javascript_include_tag "xmlhr.js"
# => <script src="/assets/xmlhr.js?1284139606"></script>

javascript_include_tag "common.javascript", "/elsewhere/cools"
# => <script src="/assets/common.javascript?1284139606"></script>
#    <script src="/elsewhere/cools.js?1423139606"></script>

javascript_include_tag "http://www.example.com/xmlhr"
# => <script src="http://www.example.com/xmlhr"></script>

javascript_include_tag "http://www.example.com/xmlhr.js"
# => <script src="http://www.example.com/xmlhr.js"></script>

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 52

def javascript_include_tag(*sources)
  options = sources.extract_options!.stringify_keys
  path_options = options.extract!('protocol').symbolize_keys

  sources.uniq.map { |source|
    tag_options = {
      "src" => path_to_javascript(source, path_options)
    }.merge!(options)
    (:script, "", tag_options)
  }.join("\n").html_safe
end

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. For historical reasons, the 'media' attribute will always be present and defaults to “screen”, so you must explicitly set it to “all” for the stylesheet(s) to apply to all media types.

stylesheet_link_tag "style"
# => <link href="/assets/style.css" media="screen" rel="stylesheet" />

stylesheet_link_tag "style.css"
# => <link href="/assets/style.css" media="screen" rel="stylesheet" />

stylesheet_link_tag "http://www.example.com/style.css"
# => <link href="http://www.example.com/style.css" media="screen" rel="stylesheet" />

stylesheet_link_tag "style", media: "all"
# => <link href="/assets/style.css" media="all" rel="stylesheet" />

stylesheet_link_tag "style", media: "print"
# => <link href="/assets/style.css" media="print" rel="stylesheet" />

stylesheet_link_tag "random.styles", "/css/stylish"
# => <link href="/assets/random.styles" media="screen" rel="stylesheet" />
#    <link href="/css/stylish.css" media="screen" rel="stylesheet" />

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 89

def stylesheet_link_tag(*sources)
  options = sources.extract_options!.stringify_keys
  path_options = options.extract!('protocol').symbolize_keys

  sources.uniq.map { |source|
    tag_options = {
      "rel" => "stylesheet",
      "media" => "screen",
      "href" => path_to_stylesheet(source, path_options)
    }.merge!(options)
    tag(:link, tag_options)
  }.join("\n").html_safe
end

#video_tag(*sources) ⇒ Object

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:

  • :poster - Set an image (like a screenshot) to be shown before the video loads. The path is calculated like the src of image_tag.

  • :size - Supplied as “WidthxHeight”, so “30x45” becomes width=“30” and height=“45”. :size 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="/assets/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="/videos/trailer.ogg" /><source src="/videos/trailer.flv" /></video>
video_tag(["trailer.ogg", "trailer.flv"])
# => <video><source src="/videos/trailer.ogg" /><source src="/videos/trailer.flv" /></video>
video_tag(["trailer.ogg", "trailer.flv"], size: "160x120")
# => <video height="120" width="160"><source src="/videos/trailer.ogg" /><source src="/videos/trailer.flv" /></video>

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# File 'lib/action_view/helpers/asset_tag_helper.rb', line 276

def video_tag(*sources)
  multiple_sources_tag('video', sources) do |options|
    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
  end
end