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Class: Sprockets::UnloadedAsset

Relationships & Source Files
Inherits: Object
Defined in: lib/sprockets/unloaded_asset.rb

Overview

Internal: Used to parse and store the URI to an unloaded asset Generates keys used to store and retrieve items from cache

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(uri, env) ⇒ UnloadedAsset

Internal: Initialize object for generating cache keys

uri - A String containing complete URI to a file including scheme

and full path such as
"file:///Path/app/assets/js/app.js?type=application/javascript"

env - The current “environment” that assets are being loaded into.

We need it so we know where the {root} (directory where Sprockets
is being invoked). We also need it for the {file_digest} method,
since, for some strange reason, memoization is provided by
overriding methods such as {stat} in the {PathUtils} module.

Returns UnloadedAsset.

[ GitHub ] 

  


# File 'lib/sprockets/unloaded_asset.rb', line 22



def initialize(uri, env)
  @uri               = uri.to_s
  @env               = env
  @compressed_path   = URITar.new(uri, env).compressed_path
  @params            = nil # lazy loaded
  @filename          = nil # lazy loaded
end


  







Instance Attribute Details



  

    #compressed_path   (readonly)
  

  [ GitHub ]


  

  


# File 'lib/sprockets/unloaded_asset.rb', line 29



attr_reader :compressed_path, :uri


  








  

    #uri   (readonly)
  

  [ GitHub ]


  

  


# File 'lib/sprockets/unloaded_asset.rb', line 29



attr_reader :compressed_path, :uri


  







Instance Method Details



  

    #asset_key  
  



  

    

Internal: Key of asset



Used to retrieve an asset from the cache based on “compressed” path to asset. A “compressed” path can either be relative to the root of the project or an absolute path.



Returns a String.


  



  [ GitHub ]


  

  


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



def asset_key
  "asset-uri:#{compressed_path}"
end


  








  

    #dependency_history_key  
  



  

    

Public: Dependency History key



Used to retrieve an array of “histories” each of which contains a set of stored dependencies for a given asset path and filename digest.



A dependency can refer to either an asset e.g. index.js may rely on jquery.js (so jquery.js is a dependency), or other factors that may affect compilation, such as the VERSION of ::Sprockets (i.e. the environment) and what “processors” are used.



For example a history array with one Set of dependencies may look like:



[[“environment-version”, “environment-paths”, “processors:type=text/css&file_type=text/css”,



"file-digest:///Full/path/app/assets/stylesheets/application.css",
"processors:type=text/css&file_type=text/css&pipeline=self",
"file-digest:///Full/path/app/assets/stylesheets"]]



This method of asset lookup is used to ensure that none of the dependencies have been modified since last lookup. If one of them has, the key will be different and a new entry must be stored.



URI dependencies are later converted to “compressed” paths



Returns a String.


  



  [ GitHub ]


  

  


# File 'lib/sprockets/unloaded_asset.rb', line 104



def dependency_history_key
  "asset-uri-cache-dependencies:#{compressed_path}:#{ @env.file_digest(filename) }"
end


  








  

    #digest_key(digest)  
  



  

    

Internal: Digest key



Used to retrieve a string containing the “compressed” path to an asset based on a digest. The digest is generated from dependencies stored via information stored in the #dependency_history_key after each of the “dependencies” is “resolved”. For example “environment-version” may be resolved to “environment-1.0-3.2.0” for version “3.2.0” of ::Sprockets



Returns a String.


  



  [ GitHub ]


  

  


# File 'lib/sprockets/unloaded_asset.rb', line 117



def digest_key(digest)
  "asset-uri-digest:#{compressed_path}:#{digest}"
end


  








  

    #file_digest_key(stat)  
  



  

    

Internal: File digest key



The digest for a given file won’t change if the path and the stat time hasn’t changed We can save time by not re-computing this information and storing it in the cache



Returns a String.


  



  [ GitHub ]


  

  


# File 'lib/sprockets/unloaded_asset.rb', line 127



def file_digest_key(stat)
  "file_digest:#{compressed_path}:#{stat}"
end


  








  

    #filename  
  



  

    

Internal: Full file path without schema



This returns a string containing the full path to the asset without the schema. Information is loaded lazily since we want UnloadedAsset.new(dep, self).relative_path to be fast. Calling this method the first time allocates an array and a hash.



Example



If the URI is file:///Full/path/app/assets/javascripts/application.js“ then the filename would be ”/Full/path/app/assets/javascripts/application.js“



Returns a String.


  



  [ GitHub ]


  

  


# File 'lib/sprockets/unloaded_asset.rb', line 43



def filename
  unless @filename
    load_file_params
  end
  @filename
end


  








  

    #load_file_params   (private)
  



  

    

Internal: Parses uri into filename and params hash



Returns Array with filename and params hash


  



  [ GitHub ]


  

  


# File 'lib/sprockets/unloaded_asset.rb', line 135



def load_file_params
  @filename, @params = URIUtils.parse_asset_uri(uri)
end


  








  

    #params  
  



  

    

Internal: Hash of param values



This information is generated and used internally by ::Sprockets. Known keys include :type which stores the asset’s mime-type, :id which is a fully resolved digest for the asset (includes dependency digest as opposed to a digest of only file contents) and :pipeline. Hash may be empty.



Example



If the URI is file:///Full/path/app/assets/javascripts/application.js“type=application/javascript Then the params would be {type: "application/javascript"}



Returns a Hash.


  



  [ GitHub ]


  

  


# File 'lib/sprockets/unloaded_asset.rb', line 63



def params
  unless @params
    load_file_params
  end
  @params
end