Module: Async::HTTP::Cache::Body

Defined in:
lib/async/http/cache/body.rb

Overview

Provides utilities for wrapping HTTP response bodies with caching capabilities.

Constant Summary collapse

TRAILER = 
"trailer"
ETAG = 
"etag"

Class Method Summary collapse

Class Method Details

.wrap(response, &block) ⇒ Object

Wrap a response body with caching functionality, including ETag generation and completion handling.



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# File 'lib/async/http/cache/body.rb', line 27

def self.wrap(response, &block)
	if body = response.body
		if body.empty?
			# A body that is empty? at the outset, is immutable. This generally only applies to HEAD requests.
			yield response, body
		else
			# Insert a rewindable body so that we can cache the response body:
			rewindable = ::Protocol::HTTP::Body::Rewindable.wrap(response)
			
			unless response.headers.include?(ETAG)
				# Add the etag header to the trailers:
				response.headers.add(TRAILER, ETAG)
				
				# Compute a digest and add it to the response headers:
				::Protocol::HTTP::Body::Digestable.wrap(response) do |wrapper|
					response.headers.add(ETAG, wrapper.etag)
				end
			end
			
			# Wrap the response with the callback:
			::Protocol::HTTP::Body::Completable.wrap(response) do |error|
				if error
					Console::Event::Failure.for(error).emit(self)
				else
					yield response, rewindable.buffered
				end
			end
		end
	else
		yield response, nil
	end
	
	return response
end