Class: Rack::Deflater

Inherits:
Object show all
Defined in:
lib/gems/rack-0.9.1/lib/rack/deflater.rb

Constant Summary collapse

DEFLATE_ARGS = 
[
  Zlib::DEFAULT_COMPRESSION,
  # drop the zlib header which causes both Safari and IE to choke
 -Zlib::MAX_WBITS,
  Zlib::DEF_MEM_LEVEL,
  Zlib::DEFAULT_STRATEGY
]

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ Deflater

Returns a new instance of Deflater.



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# File 'lib/gems/rack-0.9.1/lib/rack/deflater.rb', line 8

def initialize(app)
  @app = app
end

Class Method Details

.deflate(body) ⇒ Object

Loosely based on Mongrel’s Deflate handler



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# File 'lib/gems/rack-0.9.1/lib/rack/deflater.rb', line 77

def self.deflate(body)
  deflater = Zlib::Deflate.new(*DEFLATE_ARGS)

  # TODO: Add streaming
  body.each { |part| deflater << part }

  return deflater.finish
end

.gzip(body, mtime) ⇒ Object 



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# File 'lib/gems/rack-0.9.1/lib/rack/deflater.rb', line 56

def self.gzip(body, mtime)
  io = StringIO.new
  gzip = Zlib::GzipWriter.new(io)
  gzip.mtime = mtime

  # TODO: Add streaming
  body.each { |part| gzip << part }

  gzip.close
  return io.string
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/gems/rack-0.9.1/lib/rack/deflater.rb', line 12

def call(env)
  status, headers, body = @app.call(env)
  headers = Utils::HeaderHash.new(headers)

  # Skip compressing empty entity body responses and responses with
  # no-transform set.
  if Utils::STATUS_WITH_NO_ENTITY_BODY.include?(status) ||
      headers['Cache-Control'].to_s =~ /\bno-transform\b/
    return [status, headers, body]
  end

  request = Request.new(env)

  encoding = Utils.select_best_encoding(%w(gzip deflate identity),
                                        request.accept_encoding)

  # Set the Vary HTTP header.
  vary = headers["Vary"].to_s.split(",").map { |v| v.strip }
  unless vary.include?("*") || vary.include?("Accept-Encoding")
    headers["Vary"] = vary.push("Accept-Encoding").join(",")
  end

  case encoding
  when "gzip"
    mtime = if headers.key?("Last-Modified") 
              Time.httpdate(headers["Last-Modified"]) 
            else 
              Time.now
            end
    [status,
     headers.merge("Content-Encoding" => "gzip"),
     self.class.gzip(body, mtime)]
  when "deflate"
    [status,
     headers.merge("Content-Encoding" => "deflate"),
     self.class.deflate(body)]
  when "identity"
    [status, headers, body]
  when nil
    message = ["An acceptable encoding for the requested resource #{request.fullpath} could not be found."]
    [406, {"Content-Type" => "text/plain"}, message]
  end
end