Class: Sprockets::Context

Inherits:
Object
  • Object
show all
Defined in:
lib/sprockets/context.rb

Overview

`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.instance_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.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(environment, logical_path, pathname) ⇒ Context

Returns a new instance of Context



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# File 'lib/sprockets/context.rb', line 28

def initialize(environment, logical_path, pathname)
  @environment  = environment
  @logical_path = logical_path
  @pathname     = pathname
  @__LINE__     = nil

  @_required_paths    = []
  @_dependency_paths  = Set.new([pathname.to_s])
  @_dependency_assets = Set.new
end

Instance Attribute Details

#__LINE__=(value) ⇒ Object (writeonly)

Sets the attribute __LINE__

Parameters:

  • value

    the value to set the attribute __LINE__ to.



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# File 'lib/sprockets/context.rb', line 26

def __LINE__=(value)
  @__LINE__ = value
end

#_dependency_assetsObject (readonly)

Returns the value of attribute _dependency_assets



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# File 'lib/sprockets/context.rb', line 25

def _dependency_assets
  @_dependency_assets
end

#_dependency_pathsObject (readonly)

Returns the value of attribute _dependency_paths



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# File 'lib/sprockets/context.rb', line 25

def _dependency_paths
  @_dependency_paths
end

#_required_pathsObject (readonly)

Returns the value of attribute _required_paths



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# File 'lib/sprockets/context.rb', line 25

def _required_paths
  @_required_paths
end

#environmentObject (readonly)

Returns the value of attribute environment



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# File 'lib/sprockets/context.rb', line 24

def environment
  @environment
end

#pathnameObject (readonly)

Returns the value of attribute pathname



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# File 'lib/sprockets/context.rb', line 24

def pathname
  @pathname
end

Instance Method Details

#asset_data_uri(path) ⇒ Object

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' %>) }



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# File 'lib/sprockets/context.rb', line 195

def asset_data_uri(path)
  depend_on(path)
  asset  = environment.find_asset(path)
  base64 = Base64.encode64(asset.to_s).gsub(/\s+/, "")
  "data:#{asset.content_type};base64,#{Rack::Utils.escape(base64)}"
end

#asset_requirable?(path) ⇒ Boolean

Tests if target path is able to be safely required into the current concatenation.

Returns:

  • (Boolean)


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# File 'lib/sprockets/context.rb', line 148

def asset_requirable?(path)
  pathname = resolve(path)
  content_type = environment.content_type_of(pathname)
  pathname.file? && (self.content_type.nil? || self.content_type == content_type)
end

#content_typeObject

Returns content type of file

'application/javascript'
'text/css'


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# File 'lib/sprockets/context.rb', line 62

def content_type
  environment.content_type_of(pathname)
end

#depend_on(path) ⇒ Object

`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.



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# File 'lib/sprockets/context.rb', line 112

def depend_on(path)
  @_dependency_paths << resolve(path).to_s
  nil
end

#depend_on_asset(path) ⇒ Object

`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.



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# File 'lib/sprockets/context.rb', line 124

def depend_on_asset(path)
  filename = resolve(path).to_s
  @_dependency_assets << filename
  nil
end

#evaluate(path, options = {}) ⇒ Object

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" %>


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# File 'lib/sprockets/context.rb', line 161

def evaluate(path, options = {})
  pathname   = resolve(path)
  attributes = environment.attributes_for(pathname)
  processors = options[:processors] || attributes.processors

  if options[:data]
    result = options[:data]
  else
    result = Sprockets::Utils.read_unicode(pathname)
  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

#logical_pathObject

Returns logical path without any file extensions.

'app/javascripts/application.js'
# => 'application'


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# File 'lib/sprockets/context.rb', line 53

def logical_path
  @logical_path[/^([^.]+)/, 0]
end

#require_asset(path) ⇒ Object

`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" %>


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# File 'lib/sprockets/context.rb', line 139

def require_asset(path)
  pathname = resolve(path, :content_type => :self)
  depend_on_asset(pathname)
  @_required_paths << pathname.to_s
  nil
end

#resolve(path, options = {}, &block) ⇒ Object

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"


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# File 'lib/sprockets/context.rb', line 77

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

#root_pathObject

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`.



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# File 'lib/sprockets/context.rb', line 44

def root_path
  environment.paths.detect { |path| pathname.to_s[path] }
end