class Protocol::HTTP::ContentEncoding

Encode a response according the the request’s acceptable encodings.

def call(request)

@returns [Response] The response.
@parameter request [Request] The request.

Encode the response body according to the request's acceptable encodings. 
def call(request)
	response = super
	
	# Early exit if the response has already specified a content-encoding.
	return response if response.headers["content-encoding"]
	
	# This is a very tricky issue, so we avoid it entirely.
	# https://lists.w3.org/Archives/Public/ietf-http-wg/2014JanMar/1179.html
	return response if response.partial?
	
	body = response.body
	
	# If there is no response body, there is nothing to encode:
	return response if body.nil? or body.empty?
	
	# Ensure that caches are aware we are varying the response based on the accept-encoding request header:
	response.headers.add("vary", "accept-encoding")
	
	if accept_encoding = request.headers["accept-encoding"]
		if content_type = response.headers["content-type"] and @content_types =~ content_type
			accept_encoding.each do |name|
				if wrapper = @wrappers[name]
					response.headers["content-encoding"] = name
					
					body = wrapper.call(body)
					
					break
				end
			end
			
			response.body = body
		end
	end
	
	return response
end

def initialize(delegate, content_types = DEFAULT_CONTENT_TYPES, wrappers = DEFAULT_WRAPPERS)

@parameter wrappers [Hash] The encoding wrappers to use.
@parameter content_types [Regexp] The content types to apply encoding to.
@parameter delegate [Middleware] The next middleware in the chain.

Initialize the content encoding middleware. 
def initialize(delegate, content_types = DEFAULT_CONTENT_TYPES, wrappers = DEFAULT_WRAPPERS)
	super(delegate)
	
	@content_types = content_types
	@wrappers = wrappers
end