class Sprockets::Manifest - sprockets-2.11.3 Documentation

# class Sprockets::Manifest

The Manifest logs the contents of assets compiled to a single directory. It records basic attributes about the asset for fast lookup without having to compile. A pointer from each logical path indicates with fingerprinted asset is the current one.

The JSON is part of the public API and should be considered stable. This should make it easy to read from other programming languages and processes that don't have sprockets loaded. See `#assets` and `#files` for more infomation about the structure.

### Attributes

dir[R]
environment[R]
path[R]

### Public Class Methods

new(*args) click to toggle source

Create new Manifest associated with an `environment`. `path` is a full path to the manifest json file. The file may or may not already exist. The dirname of the `path` will be used to write compiled assets to. Otherwise, if the path is a directory, the filename will default a random “manifest-123.json” file in that directory.

    Manifest.new(environment, "./public/assets/manifest.json")

    # File lib/sprockets/manifest.rb, line 27
    def initialize(*args)
      if args.first.is_a?(Base) || args.first.nil?
        @environment = args.shift
      end

      @dir, @path = args[0], args[1]

      # Expand paths
      @dir  = File.expand_path(@dir) if @dir
      @path = File.expand_path(@path) if @path

      # If path is given as the second arg
      if @dir && File.extname(@dir) != ""
        @dir, @path = nil, @dir
      end

      # Default dir to the directory of the path
      @dir ||= File.dirname(@path) if @path

      # If directory is given w/o path, pick a random manifest.json location
      if @dir && @path.nil?
        # Find the first manifest.json in the directory
        paths = Dir[File.join(@dir, "manifest*.json")]
        if paths.any?
          @path = paths.first
        else
          @path = File.join(@dir, "manifest-#{SecureRandom.hex(16)}.json")
        end
      end

      unless @dir && @path
        raise ArgumentError, "manifest requires output path"
      end

      data = nil

      begin
        if File.exist?(@path)
          data = json_decode(File.read(@path))
        end
      rescue MultiJson::DecodeError => e
        logger.error "#{@path} is invalid: #{e.class} #{e.message}"
      end

      @data = data.is_a?(Hash) ? data : {}
    end

### Public Instance Methods

assets() click to toggle source

Returns internal assets mapping. Keys are logical paths which map to the latest fingerprinted filename.

    Logical path (String): Fingerprint path (String)

    { "application.js" => "application-2e8e9a7c6b0aafa0c9bdeec90ea30213.js",
      "jquery.js"      => "jquery-ae0908555a245f8266f77df5a8edca2e.js" }

    # File lib/sprockets/manifest.rb, line 82
    def assets
      @data['assets'] ||= {}
    end

clean(keep = 2) click to toggle source

Cleanup old assets in the compile directory. By default it will keep the latest version plus 2 backups.

    # File lib/sprockets/manifest.rb, line 171
    def clean(keep = 2)
      self.assets.keys.each do |logical_path|
        # Get assets sorted by ctime, newest first
        assets = backups_for(logical_path)

        # Keep the last N backups
        assets = assets[keep..-1] || []

        # Remove old assets
        assets.each { |path, _| remove(path) }
      end
    end

clobber() click to toggle source

Wipe directive

    # File lib/sprockets/manifest.rb, line 185
    def clobber
      FileUtils.rm_r(@dir) if File.exist?(@dir)
      logger.info "Removed #{@dir}"
      nil
    end

compile(*args) click to toggle source

Compile and write asset to directory. The asset is written to a fingerprinted filename like `application-2e8e9a7c6b0aafa0c9bdeec90ea30213.js`. An entry is also inserted into the manifest file.

    compile("application.js")

    # File lib/sprockets/manifest.rb, line 110
    def compile(*args)
      unless environment
        raise Error, "manifest requires environment for compilation"
      end

      paths = environment.each_logical_path(*args).to_a +
        args.flatten.select { |fn| Pathname.new(fn).absolute? if fn.is_a?(String)}

      paths.each do |path|
        if asset = find_asset(path)
          files[asset.digest_path] = {
            'logical_path' => asset.logical_path,
            'mtime'        => asset.mtime.iso8601,
            'size'         => asset.bytesize,
            'digest'       => asset.digest
          }
          assets[asset.logical_path] = asset.digest_path

          target = File.join(dir, asset.digest_path)

          if File.exist?(target)
            logger.debug "Skipping #{target}, already exists"
          else
            logger.info "Writing #{target}"
            asset.write_to target
            asset.write_to "#{target}.gz" if asset.is_a?(BundledAsset)
          end

        end
      end
      save
      paths
    end

files() click to toggle source

Returns internal file directory listing. Keys are filenames which map to an attributes array.

     Fingerprint path (String):
       logical_path: Logical path (String)
       mtime: ISO8601 mtime (String)
       digest: Base64 hex digest (String)

    { "application-2e8e9a7c6b0aafa0c9bdeec90ea30213.js" =>
        { 'logical_path' => "application.js",
          'mtime' => "2011-12-13T21:47:08-06:00",
          'digest' => "2e8e9a7c6b0aafa0c9bdeec90ea30213" } }

    # File lib/sprockets/manifest.rb, line 99
    def files
      @data['files'] ||= {}
    end

remove(filename) click to toggle source

Removes file from directory and from manifest. `filename` must be the name with any directory path.

    manifest.remove("application-2e8e9a7c6b0aafa0c9bdeec90ea30213.js")

    # File lib/sprockets/manifest.rb, line 149
    def remove(filename)
      path = File.join(dir, filename)
      gzip = "#{path}.gz"
      logical_path = files[filename]['logical_path']

      if assets[logical_path] == filename
        assets.delete(logical_path)
      end

      files.delete(filename)
      FileUtils.rm(path) if File.exist?(path)
      FileUtils.rm(gzip) if File.exist?(gzip)

      save

      logger.info "Removed #{filename}"

      nil
    end

### Protected Instance Methods

backups_for(logical_path) click to toggle source

Finds all the backup assets for a logical path. The latest version is always excluded. The return array is sorted by the assets mtime in descending order (Newest to oldest).

    # File lib/sprockets/manifest.rb, line 195
    def backups_for(logical_path)
      files.select { |filename, attrs|
        # Matching logical paths
        attrs['logical_path'] == logical_path &&
          # Excluding whatever asset is the current
          assets[logical_path] != filename
      }.sort_by { |filename, attrs|
        # Sort by timestamp
        Time.parse(attrs['mtime'])
      }.reverse
    end

find_asset(logical_path) click to toggle source

Basic wrapper around Sprockets::Environment#find_asset. Logs compile time.

    # File lib/sprockets/manifest.rb, line 208
    def find_asset(logical_path)
      asset = nil
      ms = benchmark do
        asset = environment.find_asset(logical_path)
      end
      logger.debug "Compiled #{logical_path}  (#{ms}ms)"
      asset
    end

save() click to toggle source

Persist manfiest back to FS

    # File lib/sprockets/manifest.rb, line 218
    def save
      FileUtils.mkdir_p dir
      File.open(path, 'w') do |f|
        f.write json_encode(@data)
      end
    end

### Private Instance Methods

benchmark() { || ... } click to toggle source

    # File lib/sprockets/manifest.rb, line 255
    def benchmark
      start_time = Time.now.to_f
      yield
      ((Time.now.to_f - start_time) * 1000).to_i
    end

json_decode(obj) click to toggle source

    # File lib/sprockets/manifest.rb, line 228
    def json_decode(obj)
      MultiJson.load(obj)
    end

json_encode(obj) click to toggle source

    # File lib/sprockets/manifest.rb, line 232
    def json_encode(obj)
      MultiJson.dump(obj)
    end

logger() click to toggle source

    # File lib/sprockets/manifest.rb, line 245
    def logger
      if environment
        environment.logger
      else
        logger = Logger.new($stderr)
        logger.level = Logger::FATAL
        logger
      end
    end