Class: Rack::Brotli::Deflater

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/brotli/deflater.rb

Overview

This middleware enables compression of http responses with the ‘br` encoding, when support is detected and allowed.

Defined Under Namespace

Classes: BrotliStream

Instance Method Summary collapse

Constructor Details

#initialize(app, options = {}) ⇒ Deflater

Creates Rack::Brotli middleware.

app

rack app instance

options

hash of deflater options, i.e. ‘if’ - a lambda enabling / disabling deflation based on returned boolean value

e.g use Rack::Brotli, :if => lambda { |env, status, headers, body| body.map(&:bytesize).reduce(0, :+) > 512 }

‘include’ - a list of content types that should be compressed ‘deflater’ - Brotli compression options Hash (see brotli.org/encode.html#a4d4 and github.com/miyucy/brotli/blob/ea0e058031177e5cc42e361f7d2702a951048a31/ext/brotli/brotli.c#L119-L180)

- 'mode'
- 'quality'
- 'lgwin'
- 'lgblock'



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# File 'lib/rack/brotli/deflater.rb', line 25

def initialize(app, options = {})
  @app = app

  @condition = options[:if]
  @compressible_types = options[:include]
  @deflater_options = { quality: 5 }.merge(options.fetch(:deflater, {}))
  @sync = options.fetch(:sync, true)
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/rack/brotli/deflater.rb', line 34

def call(env)
  status, headers, body = response = @app.call(env)

  unless should_deflate?(env, status, headers, body)
    return response
  end

  request = Rack::Request.new(env)

  encoding = Rack::Utils.select_best_encoding(%w(br identity), request.accept_encoding)

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

  case encoding
  when "br"
    headers['content-encoding'] = "br"
    headers.delete(Rack::CONTENT_LENGTH)
    response[2] = BrotliStream.new(body, @sync, @deflater_options)
    response
  when "identity"
    response
  else
    # Only possible encoding values here are 'br', 'identity', and nil
    message = "An acceptable encoding for the requested resource #{request.fullpath} could not be found."
    bp = Rack::BodyProxy.new([message]) { body.close if body.respond_to?(:close) }
    [406, { Rack::CONTENT_TYPE => "text/plain", Rack::CONTENT_LENGTH => message.length.to_s }, bp]
  end
end