asset_path

This is the entry point for all assets. When using an asset pipeline gem (e.g. propshaft or sprockets-rails), the behavior is “enhanced”. You can bypass the asset pipeline by passing in skip_pipeline: true to the options.

All other asset *_path helpers delegate through this method.

With the asset pipeline

All options passed to asset_path will be passed to compute_asset_path which is implemented by asset pipeline gems.

asset_path("application.js") # => "/assets/application-60aa4fdc5cea14baf5400fba1abf4f2a46a5166bad4772b1effe341570f07de9.js"
asset_path('application.js', host: 'example.com') # => "//example.com/assets/application.js"
asset_path("application.js", host: 'example.com', protocol: 'https') # => "https://example.com/assets/application.js"

Without the asset pipeline (skip_pipeline: true)

Accepts a type option that can specify the asset’s extension. No error checking is done to verify the source passed into asset_path is valid and that the file exists on disk.

asset_path("application.js", skip_pipeline: true)                 # => "application.js"
asset_path("filedoesnotexist.png", skip_pipeline: true)           # => "filedoesnotexist.png"
asset_path("application", type: :javascript, skip_pipeline: true) # => "/javascripts/application.js"
asset_path("application", type: :stylesheet, skip_pipeline: true) # => "/stylesheets/application.css"

Options applying to all assets

Below lists scenarios that apply to asset_path whether or not you’re using the asset pipeline.

• All fully qualified URLs are returned immediately. This bypasses the asset pipeline and all other behavior described.

  asset_path("http://www.example.com/js/xmlhr.js") # => "http://www.example.com/js/xmlhr.js"
  

• All assets that begin with a forward slash are assumed to be full URLs and will not be expanded. This will bypass the asset pipeline.

  asset_path("/foo.png") # => "/foo.png"
  

• All blank strings will be returned immediately. This bypasses the asset pipeline and all other behavior described.

  asset_path("") # => ""
  

• If config.relative_url_root is specified, all assets will have that root prepended.

  Rails.application.config.relative_url_root = "bar"
  asset_path("foo.js", skip_pipeline: true) # => "bar/foo.js"
  

• A different asset host can be specified via config.action_controller.asset_host this is commonly used in conjunction with a CDN.

  Rails.application.config.action_controller.asset_host = "assets.example.com"
  asset_path("foo.js", skip_pipeline: true) # => "http://assets.example.com/foo.js"
  

• An extension name can be specified manually with extname.

  asset_path("foo", skip_pipeline: true, extname: ".js")     # => "/foo.js"
  asset_path("foo.css", skip_pipeline: true, extname: ".js") # => "/foo.css.js"