Class: Ram::Compressor

Inherits:
Object
  • Object
show all
Defined in:
lib/ram/compressor.rb

Overview

Uses the YUI Compressor or Closure Compiler to compress JavaScript. Always uses YUI to compress CSS (Which means that Java must be installed.) Also knows how to create a concatenated JST file. If “embed_assets” is turned on, creates “mhtml” and “datauri” versions of all stylesheets, with all enabled assets inlined into the css.

Constant Summary collapse

EMBED_MIME_TYPES =

Mapping from extension to mime-type of all embeddable assets.

{
  '.png'  => 'image/png',
  '.jpg'  => 'image/jpeg',
  '.jpeg' => 'image/jpeg',
  '.gif'  => 'image/gif',
  '.tif'  => 'image/tiff',
  '.tiff' => 'image/tiff',
  '.ttf'  => 'font/truetype',
  '.otf'  => 'font/opentype',
  '.woff' => 'font/woff'
}
EMBED_EXTS =

Font extensions for which we allow embedding:

EMBED_MIME_TYPES.keys
EMBED_FONTS = 
['.ttf', '.otf', '.woff']
MAX_IMAGE_SIZE =

(32k - padding) maximum length for data-uri assets (an IE8 limitation).

32700
EMBED_DETECTOR =

CSS asset-embedding regexes for URL rewriting.

/url\(['"]?([^\s)]+\.[a-z]+)(\?\d+)?['"]?\)/
EMBEDDABLE = 
/[\A\/]embed\//
EMBED_REPLACER = 
/url\(__EMBED__(.+?)(\?\d+)?\)/
MHTML_START =

MHTML file constants.

"/*\r\nContent-Type: multipart/related; boundary=\"MHTML_MARK\"\r\n\r\n"
MHTML_SEPARATOR = 
"--MHTML_MARK\r\n"
MHTML_END = 
"\r\n--MHTML_MARK--\r\n*/\r\n"
JST_START =

JST file constants.

"(function(){"
JST_END = 
"})();"
COMPRESSORS = 
{
  :yui      => YUI::JavaScriptCompressor,
  :closure  => Ram.compressors.include?(:closure)  ? Closure::Compiler : nil,
  :uglifier => Ram.compressors.include?(:uglifier) ? Ram::Uglifier  : nil
}
DEFAULT_OPTIONS = 
{
  :yui      => {:munge => true},
  :closure  => {},
  :uglifier => {:copyright => false}
}

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Compressor

The css compressor is always the YUI Compressor. JS compression can be provided with YUI Compressor, Google Closure Compiler or UglifyJS.



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# File 'lib/ram/compressor.rb', line 58

def initialize
  Ram.check_java_version
  @css_compressor = YUI::CssCompressor.new(Ram.css_compressor_options || {})
  flavor          = Ram.javascript_compressor || Ram::DEFAULT_COMPRESSOR
  @options        = DEFAULT_OPTIONS[flavor].merge(Ram.compressor_options || {})
  @js_compressor  = COMPRESSORS[flavor].new(@options)
end

Instance Method Details

#compile_jst(paths) ⇒ Object

Compiles a single JST file by writing out a javascript that adds template properties to a top-level template namespace object. Adds a JST-compilation function to the top of the package, unless you’ve specified your own preferred function, or turned it off. JST templates are named with the basename of their file.



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# File 'lib/ram/compressor.rb', line 97

def compile_jst(paths)
  namespace   = Ram.template_namespace
  paths       = paths.grep(Ram.template_extension_matcher).sort
  base_path   = find_base_path(paths)
  compiled    = paths.map do |path|
    contents  = read_binary_file(path)
    contents  = contents.gsub(/\r?\n/, "\\n").gsub("'", '\\\\\'')
    name      = template_name(path, base_path)
    "#{namespace}['#{name}'] = #{Ram.template_function}('#{contents}');"
  end
  compiler = Ram.include_jst_script ? read_binary_file(DEFAULT_JST_SCRIPT) : '';
  setup_namespace = "#{namespace} = #{namespace} || {};"
  [JST_START, setup_namespace, compiler, compiled, JST_END].flatten.join("\n")
end

#compress_css(paths, variant = nil, asset_url = nil) ⇒ Object

Concatenate and compress a list of CSS stylesheets. When compressing a :datauri or :mhtml variant, post-processes the result to embed referenced assets.



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# File 'lib/ram/compressor.rb', line 80

def compress_css(paths, variant=nil, asset_url=nil)
  @asset_contents = {}
  css = concatenate_and_tag_assets(paths, variant)
  css = @css_compressor.compress(css) if Ram.compress_assets
  case variant
  when nil      then return css
  when :datauri then return with_data_uris(css)
  when :mhtml   then return with_mhtml(css, asset_url)
  else raise PackageNotFound, "\"#{variant}\" is not a valid stylesheet variant"
  end
end

#compress_js(paths) ⇒ Object

Concatenate together a list of JavaScript paths, and pass them through the YUI Compressor (with munging enabled). JST can optionally be included.



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# File 'lib/ram/compressor.rb', line 68

def compress_js(paths)
  if (jst_paths = paths.grep(Ram.template_extension_matcher)).empty?
    js = concatenate(paths)
  else
    js = concatenate(paths - jst_paths) + compile_jst(jst_paths)
  end
  Ram.compress_assets ? @js_compressor.compress(js) : js
end