class Sprockets::Context
`Context` provides helper methods to all `Tilt` processors. They are typically accessed by ERB templates. You can mix in custom helpers by injecting them into `Environment#context_class`. Do not mix them into `Context` directly.
environment.context_class.class_eval do include MyHelper def asset_url; end end <%= asset_url "foo.png" %>
The `Context` also collects dependencies declared by assets. See `DirectiveProcessor` for an example of this.
Attributes
Public Class Methods
# File lib/sprockets/context.rb, line 29 def initialize(environment, logical_path, pathname) @environment = environment @logical_path = logical_path @pathname = pathname @__LINE__ = nil @_required_paths = [] @_stubbed_assets = Set.new @_dependency_paths = Set.new @_dependency_assets = Set.new([pathname.to_s]) end
Public Instance Methods
Returns a Base64-encoded `data:` URI with the contents of the asset at the specified path, and marks that path as a dependency of the current file.
Use `asset_data_uri` from ERB with CSS or JavaScript assets:
#logo { background: url(<%= asset_data_uri 'logo.png' %>) } $('<img>').attr('src', '<%= asset_data_uri 'avatar.jpg' %>')
# File lib/sprockets/context.rb, line 213 def asset_data_uri(path) depend_on_asset(path) asset = environment.find_asset(path) base64 = Base64.encode64(asset.to_s).gsub(/\s+/, "") "data:#{asset.content_type};base64,#{Rack::Utils.escape(base64)}" end
Tests if target path is able to be safely required into the current concatenation.
# File lib/sprockets/context.rb, line 158 def asset_requirable?(path) pathname = resolve(path) content_type = environment.content_type_of(pathname) stat = environment.stat(path) return false unless stat && stat.file? self.content_type.nil? || self.content_type == content_type end
Returns content type of file
'application/javascript' 'text/css'
# File lib/sprockets/context.rb, line 64 def content_type environment.content_type_of(pathname) end
`depend_on` allows you to state a dependency on a file without including it.
This is used for caching purposes. Any changes made to the dependency file with invalidate the cache of the source file.
# File lib/sprockets/context.rb, line 114 def depend_on(path) @_dependency_paths << resolve(path).to_s nil end
`depend_on_asset` allows you to state an asset dependency without including it.
This is used for caching purposes. Any changes that would invalidate the dependency asset will invalidate the source file. Unlike `depend_on`, this will include recursively include the target asset's dependencies.
# File lib/sprockets/context.rb, line 126 def depend_on_asset(path) filename = resolve(path).to_s @_dependency_assets << filename nil end
Reads `path` and runs processors on the file.
This allows you to capture the result of an asset and include it directly in another.
<%= evaluate "bar.js" %>
# File lib/sprockets/context.rb, line 173 def evaluate(path, options = {}) pathname = resolve(path) attributes = environment.attributes_for(pathname) processors = options[:processors] || attributes.processors if options[:data] result = options[:data] else if environment.respond_to?(:default_external_encoding) mime_type = environment.mime_types(pathname.extname) encoding = environment.encoding_for_mime_type(mime_type) result = Sprockets::Utils.read_unicode(pathname, encoding) else result = Sprockets::Utils.read_unicode(pathname) end end processors.each do |processor| begin template = processor.new(pathname.to_s) { result } result = template.render(self, {}) rescue Exception => e annotate_exception! e raise end end result end
Returns logical path without any file extensions.
'app/javascripts/application.js' # => 'application'
# File lib/sprockets/context.rb, line 55 def logical_path @logical_path[/^([^.]+)/, 0] end
`require_asset` declares `path` as a dependency of the file. The dependency will be inserted before the file and will only be included once.
If ERB processing is enabled, you can use it to dynamically require assets.
<%= require_asset "#{framework}.js" %>
# File lib/sprockets/context.rb, line 141 def require_asset(path) pathname = resolve(path, :content_type => :self) depend_on_asset(pathname) @_required_paths << pathname.to_s nil end
Given a logical path, `resolve` will find and return the fully expanded path. Relative paths will also be resolved. An optional `:content_type` restriction can be supplied to restrict the search.
resolve("foo.js") # => "/path/to/app/javascripts/foo.js" resolve("./bar.js") # => "/path/to/app/javascripts/bar.js"
# File lib/sprockets/context.rb, line 79 def resolve(path, options = {}, &block) pathname = Pathname.new(path) attributes = environment.attributes_for(pathname) if pathname.absolute? pathname elsif content_type = options[:content_type] content_type = self.content_type if content_type == :self if attributes.format_extension if content_type != attributes.content_type raise ContentTypeMismatch, "#{path} is " + "'#{attributes.content_type}', not '#{content_type}'" end end resolve(path) do |candidate| if self.content_type == environment.content_type_of(candidate) return candidate end end raise FileNotFound, "couldn't find file '#{path}'" else environment.resolve(path, :base_path => self.pathname.dirname, &block) end end
Returns the environment path that contains the file.
If `app/javascripts` and `app/stylesheets` are in your path, and current file is `app/javascripts/foo/bar.js`, `root_path` would return `app/javascripts`.
# File lib/sprockets/context.rb, line 46 def root_path environment.paths.detect { |path| pathname.to_s[path] } end
`stub_asset` blacklists `path` from being included in the bundle. `path` must be an asset which may or may not already be included in the bundle.
# File lib/sprockets/context.rb, line 151 def stub_asset(path) @_stubbed_assets << resolve(path, :content_type => :self).to_s nil end
Private Instance Methods
Annotates exception backtrace with the original template that the exception was raised in.
# File lib/sprockets/context.rb, line 223 def annotate_exception!(exception) location = pathname.to_s location << ":#{@__LINE__}" if @__LINE__ exception.extend(Sprockets::EngineError) exception.sprockets_annotation = " (in #{location})" end
# File lib/sprockets/context.rb, line 231 def logger environment.logger end