The AssetsMixin module provides a number of helper methods to views for linking to assets and other pages, dealing with JavaScript and CSS.
Merb provides views with convenience methods for links images and other assets.
This tests whether a random query string shall be appended to a url.
Basically, you tell it your intention and if it's ok to use default config values, and it will either use your intention or the value set in Merb::Config
@example
Merb::AssetsMixin.append_random_query_string?(options[:reload]) Merb::AssetsMixin.append_random_query_string?(options[:reload], !absolute)
@param [Boolean] intention: true if a random string shall be appended @param [Boolean] allow_default: true if it's ok to use Merb::Config @return [Boolean] true if a random query string shall be appended
# File lib/merb-assets/assets_mixin.rb, line 25 def self.append_random_query_string?(intention, allow_default = true) intention.nil? && allow_default ? Merb::Config[:reload_templates] : intention end
This tests whether a timestamp query string shall be appended to a url.
@see self.append_random_query_string?
@example
Merb::AssetsMixin.append_timestamp_query_string?(options[:timestamp]) Merb::AssetsMixin.append_timestamp_query_string?(options[:timestamp], !absolute)
@param [Boolean] intention: true if a timestamp string shall be appended @param [Boolean] allow_default: true if it's ok to use Merb::Plugins.config[:asset_timestamp] @return [Boolean] true if a timestamp query string shall be appended
# File lib/merb-assets/assets_mixin.rb, line 40 def self.append_timestamp_query_string?(intention, allow_default = true) intention.nil? && allow_default ? Merb::Plugins.config[:asset_helpers][:asset_timestamp] : intention end
asset_type<Symbol>: A symbol representing the type of the asset. asset_path<String>: The path to the asset
exists?<Boolean>
This tests whether a give asset exists in the file system.
# File lib/merb-assets/assets_mixin.rb, line 98 def asset_exists?(asset_type, asset_path) File.exists?(Merb.root / asset_path(asset_type, asset_path, true)) end
Automatically generates link for CSS and JS
We want all possible matches in the FileSys up to the action name
Given: controller_name = "namespace/controller" action_name = "action"
@example If all files are present should generate link/script tags for:
namespace.(css|js) namespace/controller.(css|js) namespace/controller/action.(css|js)
@return [String] html
# File lib/merb-assets/assets_mixin.rb, line 56 def auto_link [auto_link_css, auto_link_js].join(Merb::Const::NEWLINE) end
We want all possible matches in the file system upto the action name for CSS. The reason for separating auto_link for CSS and JS is performance concerns with page loading. See Yahoo performance rules (developer.yahoo.com/performance/rules.html)
@return [String] html
# File lib/merb-assets/assets_mixin.rb, line 66 def auto_link_css auto_link_paths.map do |path| asset_exists?(:stylesheet, path) ? css_include_tag(path) : nil end.compact.join(Merb::Const::NEWLINE) end
none
html<String>
We want all possible matches in the file system upto the action name for JS. The reason for separating auto_link for CSS and JS is performance concerns with page loading. See Yahoo performance rules (developer.yahoo.com/performance/rules.html)
# File lib/merb-assets/assets_mixin.rb, line 83 def auto_link_js auto_link_paths.map do |path| asset_exists?(:javascript, path) ? js_include_tag(path) : nil end.compact.join(Merb::Const::NEWLINE) end
none
paths<Array>
This is an auxiliary method which returns an array of all possible asset paths for the current controller/action.
# File lib/merb-assets/assets_mixin.rb, line 111 def auto_link_paths paths = (controller_name / action_name).split(Merb::Const::SLASH) first = paths.shift paths.inject( [first] ) do |memo, val| memo.push [memo.last, val].join(Merb::Const::SLASH) end end
Generate IMG tag
@param [String, to_s] img The image path. @param [Hash] opts Additional options for the image tag (see below). @option opts [String] :path
Sets the path prefix for the image. Defaults to "/images/" or whatever is specified in Merb::Config. This is ignored if img is an absolute path or full URL.
@option opts [Boolean] :reload
Override the Merb::Config[:reload_templates] value. If true, a random query param will be appended to the image url
@option opts [Boolean, String] :timestamp
Override the Merb::Plugins.config[:asset_helpers][:asset_timestamp] value. If true, a timestamp query param will be appended to the image url. The value will be File.mtime(Merb.dir_for(:public) / path). If String is passed than it will be used as the timestamp.
All other options set HTML attributes on the tag.
@example
image_tag('foo.gif') # => <img src='/images/foo.gif' /> image_tag('foo.gif', :class => 'bar') # => <img src='/images/foo.gif' class='bar' /> image_tag('foo.gif', :path => '/files/') # => <img src='/files/foo.gif' /> image_tag('http://test.com/foo.gif') # => <img src="http://test.com/foo.gif"> image_tag('charts', :path => '/dynamic/') or image_tag('/dynamic/charts') # => <img src="/dynamic/charts">
@return [String]
# File lib/merb-assets/assets_mixin.rb, line 176 def image_tag(img, opts={}) return "" if img.blank? if img[0].chr == Merb::Const::SLASH opts[:src] = "#{Merb::Config[:path_prefix]}#{img}" else opts[:path] ||= if img =~ ABSOLUTE_PATH_REGEXP absolute = true '' else "#{Merb::Config[:path_prefix]}/images/" end opts[:src] ||= opts.delete(:path) + img end opts[:src] = append_query_string(opts[:src], opts.delete(:reload), opts.delete(:timestamp), !absolute) %{<img #{ opts.to_xml_attributes } />} end
name<~to_s> |
The text of the link. |
url<~to_s> |
The URL to link to. Defaults to an empty string. |
opts<Hash> |
Additional HTML options for the link. |
link_to("The Merb home page", "http://www.merbivore.com/") # => <a href="http://www.merbivore.com/">The Merb home page</a> link_to("The Ruby home page", "http://www.ruby-lang.org", {'class' => 'special', 'target' => 'blank'}) # => <a href="http://www.ruby-lang.org" class="special" target="blank">The Ruby home page</a> link_to p.title, "/blog/show/#{p.id}" # => <a href="/blog/show/13">The Entry Title</a>
# File lib/merb-assets/assets_mixin.rb, line 134 def link_to(name, url='', opts={}) opts[:href] ||= url %{<a #{ opts.to_xml_attributes }>#{name}</a>} end
The key to making a fast web application is to reduce both the amount of data transfered and the number of client-server interactions. While having many small, module Javascript or stylesheet files aids in the development process, your web application will benefit from bundling those assets in the production environment.
An asset bundle is a set of asset files which are combined into a single file. This reduces the number of requests required to render a page, and can reduce the amount of data transfer required if you're using gzip encoding.
Asset bundling is always enabled in production mode, and can be optionally enabled in all environments by setting the :bundle_assets value in config/merb.yml to true.
In the development environment, this:
js_include_tag :prototype, :lowpro, :bundle => true
will produce two <script> elements. In the production mode, however, the two files will be concatenated in the order given into a single file, all.js, in the public/javascripts directory.
To specify a different bundle name:
css_include_tag :typography, :whitespace, :bundle => :base css_include_tag :header, :footer, :bundle => "content" css_include_tag :lightbox, :images, :bundle => "lb.css"
(base.css, content.css, and lb.css will all be created in the public/stylesheets directory.)
To use a Javascript or CSS compressor, like JSMin or YUI Compressor:
Merb::Assets::JavascriptAssetBundler.add_callback do |filename| system("/usr/local/bin/yui-compress #{filename}") end Merb::Assets::StylesheetAssetBundler.add_callback do |filename| system("/usr/local/bin/css-min #{filename}") end
These blocks will be run after a bundle is created.
Combining the require_css and require_js helpers with bundling can be problematic. You may want to separate out the common assets for your application -- Javascript frameworks, common CSS, etc. -- and bundle those in a "base" bundle. Then, for each section of your site, bundle the required assets into a section-specific bundle.
N.B.: If you bundle an inconsistent set of assets with the same name, you will have inconsistent results. Be thorough and test often.
In your application layout:
js_include_tag :prototype, :lowpro, :bundle => :base
In your controller layout:
require_js :bundle => :posts
Generate CSS include tag(s).
@param [Array<*String, Hash>] stylesheets
The stylesheets to include. If the last element is a Hash, it will be used as options (see below). If ".css" is left out from the stylesheet names, it will be added to them.
@option opts <String, to_s> charset
Charset which will be used as value for charset attribute
@option opts <String, to_s> bundle
The name of the bundle the stylesheets should be combined into.
@option opts <String, to_s> media
The media attribute for the generated link element. Defaults to :all.
@option opts <String, to_s> prefix
prefix to add to include tag, overrides any set in Merb::Plugins.config[:asset_helpers][:css_prefix]
@option opts <String, to_s> suffix
suffix to add to include tag, overrides any set in Merb::Plugins.config[:asset_helpers][:css_suffix]
@option opts <Boolean> reload
Override the Merb::Config[:reload_templates] value. If true, a random query param will be appended to the css url
@option opts [Boolean, String] :timestamp
Override the Merb::Plugins.config[:asset_helper][:asset_timestamp] value. If true, a timestamp query param will be appended to the image url. The value will be File.mtime(Merb.dir_for(:public) / path). If String is passed than it will be used as the timestamp.
@example
css_include_tag 'style' # => <link href="/stylesheets/style.css" media="all" rel="Stylesheet" type="text/css" charset="utf-8" /> css_include_tag 'style.css', 'layout' # => <link href="/stylesheets/style.css" media="all" rel="Stylesheet" type="text/css" charset="utf-8" /> # <link href="/stylesheets/layout.css" media="all" rel="Stylesheet" type="text/css" charset="utf-8" /> css_include_tag :menu # => <link href="/stylesheets/menu.css" media="all" rel="Stylesheet" type="text/css" charset="utf-8" /> css_include_tag :style, :screen # => <link href="/stylesheets/style.css" media="all" rel="Stylesheet" type="text/css" charset="utf-8" /> # <link href="/stylesheets/screen.css" media="all" rel="Stylesheet" type="text/css" charset="utf-8" /> css_include_tag :style, :media => :print # => <link href="/stylesheets/style.css" media="print" rel="Stylesheet" type="text/css" charset="utf-8" /> css_include_tag :style, :charset => 'iso-8859-1' # => <link href="/stylesheets/style.css" media="print" rel="Stylesheet" type="text/css" charset="iso-8859-1" /> css_include_tag :style, :prefix => "http://static.example.com" # => <link href="http://static.example.com/stylesheets/style.css" media="print" rel="Stylesheet" type="text/css" /> css_include_tag :style, :suffix => ".#{MyApp.version}" # => <link href="/stylesheets/style.1.0.0.css" media="print" rel="Stylesheet" type="text/css" />
@return [String] The CSS include tag(s)
# File lib/merb-assets/assets_mixin.rb, line 622 def css_include_tag(*stylesheets) options = stylesheets.last.is_a?(Hash) ? stylesheets.pop : {} return nil if stylesheets.empty? css_prefix = options[:prefix] || Merb::Plugins.config[:asset_helpers][:css_prefix] css_suffix = options[:suffix] || Merb::Plugins.config[:asset_helpers][:css_suffix] if (bundle_name = options[:bundle]) && Merb::Assets.bundle? && stylesheets.size > 1 bundler = Merb::Assets::StylesheetAssetBundler.new(bundle_name, *stylesheets) bundled_asset = bundler.bundle! return css_include_tag(bundled_asset) end tags = "" reload = options.delete(:reload) timestamp = options.delete(:timestamp) for stylesheet in stylesheets href = css_prefix.to_s + asset_path(:stylesheet, stylesheet) if css_suffix ext_length = ASSET_FILE_EXTENSIONS[:stylesheet].length + 1 href.insert(-ext_length,css_suffix) end href = append_query_string(href, reload, timestamp) attrs = { :href => href, :type => "text/css", :rel => "Stylesheet", :charset => options[:charset] || "utf-8", :media => options[:media] || :all } tags << %{<link #{attrs.to_xml_attributes} />} end return tags end
A method used in the layout of an application to create +<link>+ tags for CSS stylesheets required in in templates and subtemplates using require_css.
options<Hash> |
Options to pass to css_include_tag. |
String |
The CSS tag. |
:bundle<~to_s> |
The name of the bundle the stylesheets should be combined into. |
:media<~to_s> |
The media attribute for the generated link element. Defaults to :all. |
# my_action.herb has a call to require_css 'style' # File: layout/application.html.erb include_required_css # => <link href="/stylesheets/style.css" media="all" rel="Stylesheet" type="text/css"/> # my_action.herb has a call to require_css 'style', 'ie-specific' # File: layout/application.html.erb include_required_css # => <link href="/stylesheets/style.css" media="all" rel="Stylesheet" type="text/css"/> # <link href="/stylesheets/ie-specific.css" media="all" rel="Stylesheet" type="text/css"/>
# File lib/merb-assets/assets_mixin.rb, line 475 def include_required_css(options = {}) required_css(options).map { |req_js| css_include_tag(*req_js) }.join end
A method used in the layout of an application to create +<script>+ tags to include JavaScripts required in in templates and subtemplates using require_js.
options<Hash> |
Options to pass to js_include_tag. |
:bundle<~to_s> |
The name of the bundle the scripts should be combined into. |
String |
The JavaScript tag. |
# my_action.herb has a call to require_js 'jquery' # File: layout/application.html.erb include_required_js # => <script src="/javascripts/jquery.js" type="text/javascript"></script> # my_action.herb has a call to require_js 'jquery', 'effects', 'validation' # File: layout/application.html.erb include_required_js # => <script src="/javascripts/jquery.js" type="text/javascript"></script> # <script src="/javascripts/effects.js" type="text/javascript"></script> # <script src="/javascripts/validation.js" type="text/javascript"></script>
# File lib/merb-assets/assets_mixin.rb, line 443 def include_required_js(options = {}) required_js(options).map { |req_js| js_include_tag(*req_js) }.join end
Generate JavaScript include tag(s).
@param [Array] scripts
The scripts to include. If the last element is a Hash, it will be used as options (see below). If ".js" is left out from the script names, it will be added to them.
:charset<~to_s> |
Charset which will be used as value for charset attribute |
:bundle<~to_s> |
The name of the bundle the scripts should be combined into. |
:prefix<~to_s> |
prefix to add to include tag, overrides any set in Merb::Plugins.config[:js_prefix] |
:suffix<~to_s> |
suffix to add to include tag, overrides any set in Merb::Plugins.config[:js_suffix] |
:reload<Boolean> |
Override the Merb::Config value. If true, a random query param will be appended to the js url |
@option opts [Boolean, String] :timestamp
Override the Merb::Plugins.config[:asset_helpers][:asset_timestamp] value. If true, a timestamp query param will be appended to the image url. The value will be File.mtime(Merb.dir_for(:public) / path). If String is passed than it will be used as the timestamp.
@example
js_include_tag 'jquery' # => <script src="/javascripts/jquery.js" type="text/javascript" charset="utf-8"></script> js_include_tag 'jquery', :charset => 'iso-8859-1' # => <script src="/javascripts/jquery.js" type="text/javascript" charset="iso-8859-1"></script> js_include_tag 'moofx.js', 'upload' # => <script src="/javascripts/moofx.js" type="text/javascript" charset="utf-8"></script> # <script src="/javascripts/upload.js" type="text/javascript" charset="utf-8"></script> js_include_tag :effects # => <script src="/javascripts/effects.js" type="text/javascript" charset="utf-8"></script> js_include_tag :jquery, :validation # => <script src="/javascripts/jquery.js" type="text/javascript" charset="utf-8"></script> # <script src="/javascripts/validation.js" type="text/javascript" charset="utf-8"></script> js_include_tag :application, :validation, :prefix => "http://cdn.example.com" # => <script src="http://cdn.example.com/javascripts/application.js" type="text/javascript" charset="utf-8"></script> # <script src="http://cdn.example.com/javascripts/validation.js" type="text/javascript" charset="utf-8"></script> js_include_tag :application, :validation, :suffix => ".#{MyApp.version}" # => <script src="/javascripts/application.1.0.3.js" type="text/javascript" charset="utf-8"></script> # <script src="/javascripts/validation.1.0.3.js" type="text/javascript" charset="utf-8"></script>
@return [String] The JavaScript include tag(s).
# File lib/merb-assets/assets_mixin.rb, line 530 def js_include_tag(*scripts) options = scripts.last.is_a?(Hash) ? scripts.pop : {} return nil if scripts.empty? js_prefix = options[:prefix] || Merb::Plugins.config[:asset_helpers][:js_prefix] js_suffix = options[:suffix] || Merb::Plugins.config[:asset_helpers][:js_suffix] if (bundle_name = options[:bundle]) && Merb::Assets.bundle? && scripts.size > 1 bundler = Merb::Assets::JavascriptAssetBundler.new(bundle_name, *scripts) bundled_asset = bundler.bundle! return js_include_tag(bundled_asset) end tags = "" for script in scripts src = js_prefix.to_s + asset_path(:javascript, script) if js_suffix ext_length = ASSET_FILE_EXTENSIONS[:javascript].length + 1 src.insert(-ext_length,js_suffix) end src = append_query_string(src, options.delete(:reload), options.delete(:timestamp)) attrs = { :src => src, :type => "text/javascript", :charset => options[:charset] || "utf-8" } tags << %{<script #{attrs.to_xml_attributes}></script>} end return tags end
The require_css method can be used to require any CSS file anywhere in your templates. Regardless of how many times a single stylesheet is included with require_css, Merb will only include it once in the header.
*css<~to_s> |
CSS files to include. |
<% require_css('style') %> # A subsequent call to include_required_css will render... # => <link href="/stylesheets/style.css" media="all" rel="Stylesheet" type="text/css"/> <% require_css('style', 'ie-specific') %> # A subsequent call to include_required_css will render... # => <link href="/stylesheets/style.css" media="all" rel="Stylesheet" type="text/css"/> # <link href="/stylesheets/ie-specific.css" media="all" rel="Stylesheet" type="text/css"/>
# File lib/merb-assets/assets_mixin.rb, line 403 def require_css(*css) @required_css ||= [] @required_css << css end
The require_js method can be used to require any JavaScript file anywhere in your templates. Regardless of how many times a single script is included with require_js, Merb will only include it once in the header.
*js<~to_s> |
JavaScript files to include. |
<% require_js 'jquery' %> # A subsequent call to include_required_js will render... # => <script src="/javascripts/jquery.js" type="text/javascript"></script> <% require_js 'jquery', 'effects' %> # A subsequent call to include_required_js will render... # => <script src="/javascripts/jquery.js" type="text/javascript"></script> # <script src="/javascripts/effects.js" type="text/javascript"></script>
# File lib/merb-assets/assets_mixin.rb, line 373 def require_js(*js) @required_js ||= [] @required_js << js end
All css files to include, without duplicates.
options<Hash> |
Default options to pass to css_include_tag. |
# File lib/merb-assets/assets_mixin.rb, line 412 def required_css(options = {}) extract_required_files(@required_css, options) end
All javascript files to include, without duplicates.
options<Hash> |
Default options to pass to js_include_tag. |
# File lib/merb-assets/assets_mixin.rb, line 382 def required_js(options = {}) extract_required_files(@required_js, options) end
*assets |
Creates unique paths for stylesheet files (prepends "/stylesheets" and appends ".css") |
Array |
Full unique paths to assets OR |
String |
if only a single path is requested |
uniq_css_path("my") #=> "http://assets2.my-awesome-domain.com/stylesheets/my.css" uniq_css_path(["admin/secrets","home/signup"]) #=> ["http://assets2.my-awesome-domain.com/stylesheets/admin/secrets.css", "http://assets1.my-awesome-domain.com/stylesheets/home/signup.css"]
# File lib/merb-assets/assets_mixin.rb, line 728 def uniq_css_path(*assets) paths = [] assets.flatten.each do |filename| paths.push(Merb::Assets::UniqueAssetPath.build(asset_path(:stylesheet,filename))) end paths.length > 1 ? paths : paths.first end
*assets |
As uniq_css_tag but has unique path |
Array |
Full unique paths to assets OR |
String |
if only a single path is requested |
uniq_css_tag("my") #=> <link href="http://assets2.my-awesome-domain.com/stylesheets/my.css" type="text/css" />
# File lib/merb-assets/assets_mixin.rb, line 760 def uniq_css_tag(*assets) css_include_tag(*uniq_css_path(assets)) end
*assets |
Creates unique paths for javascript files (prepends "/javascripts" and appends ".js") |
Array |
Full unique paths to assets OR |
String |
if only a single path is requested |
uniq_js_path("my") #=> "http://assets2.my-awesome-domain.com/javascripts/my.js" uniq_js_path(["admin/secrets","home/signup"]) #=> ["http://assets2.my-awesome-domain.com/javascripts/admin/secrets.js", "http://assets1.my-awesome-domain.com/javascripts/home/signup.js"]
# File lib/merb-assets/assets_mixin.rb, line 706 def uniq_js_path(*assets) paths = [] assets.flatten.each do |filename| paths.push(Merb::Assets::UniqueAssetPath.build(asset_path(:javascript,filename))) end paths.length > 1 ? paths : paths.first end
*assets |
As js_include_tag but has unique path |
Array |
Full unique paths to assets OR |
String |
if only a single path is requested |
uniq_js_tag("my") #=> <script type="text/javascript" src="http://assets2.my-awesome-domain.com/javascripts/my.js"></script>
# File lib/merb-assets/assets_mixin.rb, line 746 def uniq_js_tag(*assets) js_include_tag(*uniq_js_path(assets)) end
*assets |
The assets to include. These should be the full paths to any static served file |
Array |
Full unique paths to assets OR |
String |
if only a single path is requested |
uniq_path("/javascripts/my.js","/javascripts/my.css") #=> ["http://assets2.my-awesome-domain.com/javascripts/my.js", "http://assets1.my-awesome-domain.com/javascripts/my.css"] uniq_path(["/javascripts/my.js","/stylesheets/my.css"]) #=> ["http://assets2.my-awesome-domain.com/javascripts/my.js", "http://assets1.my-awesome-domain.com/stylesheets/my.css"] uniq_path(%w(/javascripts/my.js /stylesheets/my.css)) #=> ["http://assets2.my-awesome-domain.com/javascripts/my.js", "http://assets1.my-awesome-domain.com/stylesheets/my.css"] uniq_path('/stylesheets/somearbitrary.css') #=> "http://assets3.my-awesome-domain.com/stylesheets/somearbitrary.css" uniq_path('/images/hostsexypicture.jpg') #=>"http://assets1.my-awesome-domain.com/images/hostsexypicture.jpg"
# File lib/merb-assets/assets_mixin.rb, line 684 def uniq_path(*assets) paths = [] assets.flatten.each do |filename| paths.push(Merb::Assets::UniqueAssetPath.build(filename)) end paths.length > 1 ? paths : paths.first end
You can use require_js(:prototype) or require_css(:shinystyles) from any view or layout, and the scripts will only be included once in the head of the final page. To get this effect, the head of your layout you will need to include a call to include_required_js and include_required_css.
# File: app/views/layouts/application.html.erb <html> <head> <%= include_required_js %> <%= include_required_css %> </head> <body> <%= catch_content :layout %> </body> </html> # File: app/views/whatever/_part1.herb <% require_js 'this' -%> <% require_css 'that', 'another_one' -%> # File: app/views/whatever/_part2.herb <% require_js 'this', 'something_else' -%> <% require_css 'that' -%> # File: app/views/whatever/index.herb <%= partial(:part1) %> <%= partial(:part2) %> # Will generate the following in the final page... <html> <head> <script src="/javascripts/this.js" type="text/javascript"></script> <script src="/javascripts/something_else.js" type="text/javascript"></script> <link href="/stylesheets/that.css" media="all" rel="Stylesheet" type="text/css"/> <link href="/stylesheets/another_one.css" media="all" rel="Stylesheet" type="text/css"/> </head> . . . </html>
See each method's documentation for more information.
Generated with the Darkfish Rdoc Generator 2.