Rails plugin: treat your Adobe Flash swf files like any other asset (images, javascripts, etc...) and embed them using SWFObject 2.2
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With the swf_fu plugin, rails treats your swf files like any other asset (images, javascripts, etc…).

swf_fu (pronounced “swif-fu”, bonus joke for french speakers) uses SWFObject 2.2 to embed swf objects in HTML and supports all its options. SWFObject 2 is such a nice library that Adobe now uses it as the official way to embed swf! SWFObject's project can be found at code.google.com/p/swfobject

swf_fu has been tested with rails v2.0 up to v3.0b and has decent test coverage so rake test:plugins should reveal any incompatibility. Comments and pull requests welcome: github.com/marcandre/swf_fu


Assuming you have git installed (check with git version), it is easy to install from your applications directory:

rails plugin install git://github.com/marcandre/swf_fu.git   # rails 3

script/plugin install git://github.com/marcandre/swf_fu.git  # rails 2 (starting at 2.0.2)

For older versions of rails or without git, you can always download swf_fu from github and then install it manually:

rails plugin install ~/Download/swf_fu    # rails 3

script/plugin install ~/Downloads/swf_fu  # rails 2.x


Embedding in HTML

To embed a swf file, use swf_tag:

<%= swf_tag "i_like_flashing" %>

Exactly like images and javascripts, swf_tag will use swf_path to determine the path of the swf file; it will assume it is in /public/swfs/ unless specified otherwise and it will add the “.swf” extension automatically.

You can specify alternate content either with the options :alt => "Get Flash!" or you can use swf_tag as a block:

<% swf_tag "i_like_flashing" do %>
  Get Flash
<% end %>


  • :id - the DOM id of the flash object element that is used to contain the Flash object; defaults to the name of the swf in source

  • :width, :height - the width & height of the Flash object. Defaults to “100%”. These could also specified using :size

  • :size - the size of the Flash object, in the form “400x300”.

  • :mode - Either :dynamic (default) or :static. Refer to SWFObject's doc

  • :flashvars - a Hash of variables that are passed to the swf. Can also be a string like "foo=bar&hello=world". Defaults to {:id => the DOM id}

  • :parameters - a Hash of configuration parameters for the swf. See Adobe's doc

  • :html_options - a Hash of extra html options for the object tag.

  • :alt - HTML text that is displayed when the Flash player is not available. Defaults to a “Get Flash” image pointing to Adobe Flash's installation page. This can also be specified as a block (see embedding section). In Rails 3, this text is assumed to be HTML, so there is no need to call html_safe on it.

  • :flash_version - the version of the Flash player that is required (e.g. “7” (default) or “8.1.0”)

  • :auto_install - a swf file that will upgrade flash player if needed (defaults to “expressInstall” which was installed by swf_fu)

  • :javascript_class - specify a javascript class (e.g. “MyFlash”) for your flash object. If it exists, the initialize method will be called.

  • :initialize - arguments to pass to the initialization method of your javascript class.

  • :div_id - the DOM id of the containing div itself. Defaults to "#{option[:id]}_div"

  • :switch_off_auto_hide_show - switch off SWFObject's default hide/show behavior. SWFObject temporarily hides your SWF or alternative content until the library has decided which content to display. Defaults to nil.

You can override these default options with a global setting:

ActionView::Base.swf_default_options = {:mode => :static}   # All swf_tag will use the static mode by default

Any of these options can be a Proc, in which case it will be called each time swf_tag is called.

For example, the following will generate unique IDs:

my_swf_counter = 0
ActionView::Base.swf_default_options[:id] = Proc.new{"swf_unique_id_#{my_swf_counter+=1}"}


swf_fu will add 'swfobject' to the list of default javascript files. If you don't include the default javascripts, a simple javascript_include "swfobject" is needed.


swf_tag implements and relies on swf_path which behaves in a similar fashion to image_path, javascript_path, etc…:

swf_path("example")                            => "/swfs/example.swf"
swf_path("example.swf")                        => "/swfs/example.swf"
swf_path("fonts/optima")                       => "/swfs/fonts/optima.swf"
swf_path("/fonts/optima")                      => "/fonts/optima.swf"
swf_path("http://www.example.com/game.swf")    => "http://www.example.com/game.swf"

It takes into account the global setting asset_host, like any other asset:

ActionController::Base.asset_host = "http://assets.example.com"
image_path("logo.jpg")                         => "http://assets.example.com/images/logo.jpg"
swf_path("fonts/optima")                       => "http://assets.example.com/swfs/fonts/optima.swf""

Copyright © 2010 Marc-André Lafortune, released under the BSD license