Class: Sprockets::Utils::Gzip

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

Constant Summary collapse

COMPRESSABLE_MIME_TYPES =

What non-text mime types should we compress? This list comes from: www.fastly.com/blog/new-gzip-settings-and-deciding-what-compress

{
  "application/vnd.ms-fontobject" => true,
  "application/x-font-opentype" => true,
  "application/x-font-ttf" => true,
  "image/x-icon" => true,
  "image/svg+xml" => true
}

Instance Method Summary collapse

Constructor Details

#initialize(asset) ⇒ Gzip

Private: Generates a gzipped file based off of reference file.



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# File 'lib/sprockets/utils/gzip.rb', line 5

def initialize(asset)
  @content_type  = asset.content_type
  @source        = asset.source
  @charset       = asset.charset
end

Instance Method Details

#can_compress?(mime_types) ⇒ Boolean

Private: Returns whether or not an asset can be compressed.

We want to compress any file that is text based. You do not want to compress binary files as they may already be compressed and running them through a compression algorithm would make them larger.

Return Boolean.

Returns:

  • (Boolean) 


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# File 'lib/sprockets/utils/gzip.rb', line 29

def can_compress?(mime_types)
  # The "charset" of a mime type is present if the value is
  # encoded text. We can check this value to see if the asset
  # can be compressed.
  #
  # We also check against our list of non-text compressible mime types
  @charset || COMPRESSABLE_MIME_TYPES.include?(@content_type)
end

#cannot_compress?(mime_types) ⇒ Boolean

Private: Opposite of ‘can_compress?`.

Returns Boolean.

Returns:

  • (Boolean) 


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# File 'lib/sprockets/utils/gzip.rb', line 41

def cannot_compress?(mime_types)
  !can_compress?(mime_types)
end

#compress(target) ⇒ Object

Private: Generates a gzipped file based off of reference asset.

Compresses the target asset’s contents and puts it into a file with the same name plus a ‘.gz` extension in the same folder as the original. Does not modify the target asset.

Returns nothing.



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# File 'lib/sprockets/utils/gzip.rb', line 52

def compress(target)
  mtime = PathUtils.stat(target).mtime
  PathUtils.atomic_write("#{target}.gz") do |f|
    gz = Zlib::GzipWriter.new(f, Zlib::BEST_COMPRESSION)
    gz.mtime = mtime
    gz.write(@source)
    gz.close

    File.utime(mtime, mtime, f.path)
  end

  nil
end